Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface

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Prato" }, { "@type": "Person", "name": "Fernando Millán" }, { "@type": "Person", "name": "Marialy Rangel" }, { "@type": "Person", "name": "Andrés Márquez" }, { "@type": "Person", "name": "Luisa Carolina González" }, { "@type": "Person", "name": "Iván Ríos" }, { "@type": "Person", "name": "César García" }, { "@type": "Person", "name": "Carlos Rondón" }, { "@type": "Person", "name": "Enju Wang" } ], "publisher": { "@type": "Organization", "name": "F1000Research", "logo": { "@type": "ImageObject", "url": "https://f1000research.com/img/AMP/F1000Research_image.png", "height": 480, "width": 60 } }, "image": { "@type": "ImageObject", "url": "https://f1000research.com/img/AMP/F1000Research_image.png", "height": 1200, "width": 150 }, "description": " Background The paper describes lead ion adsorption on variable charge oxidic calcined substrates with chemically modified surfaces. Amphoteric oxides of iron, aluminum, titanium, and manganese, change their surface electric charge after acid or alkaline treatment, letting cationic or anionic adsorption reactions from aqueous solutions. This property allows using them as adsorbing substrate for heavy metals retention in water treatment systems. Methods Substrate was prepared by extruding cylindrical strips from a saturate paste of the oxidic lithological material-OLM; dries it up and thermally treated by calcination. The study was performed by triplicated trial, on batch mode, using 2 grams samples of treated with NaOH 0.1N and non-treated substrate. Lead analysis was performed by AAS-GF. Freundlich and Langmuir models were used to fit results. Comparing differential behavior between treated and non-treated substrates showed the variable charge nature of the OLM. Results Results show L-type isotherms for the adsorption of Pb(II) ions on the activated substrate, suggesting good affinity between Pb(II) ions and OLM’s surface. Average value of adsorption capacity (K) for activated substrate (1791.73±13.06), is around four times greater than the non-activated substrate (491.54±31.97), during the adsorption reaction, 0.35 and 0.26 mmolH+ of proton are produced on the activated and non-activated substrate respectively using a 1 mM Pb(II) solution and 72.2 and 15.6 mmolH+ using a 10 mM Pb(II) solution. This acidification agrees with the theoretic model of transitional metals chemisorption on amphoteric oxides, present in lithological material used for the preparation of adsorbent substrates, confirming the information given by the L-type isotherms. Conclusions Results suggest that these variable charge oxidic adsorbent substrate show great potential as an alternative technique for water treatment at small and medium scale using granular filtration system. The easiness and low price make them suitable to apply in rural media where no treating water systems is available. " } { "@context": "http://schema.org", "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": "1", "item": { "@id": "https://f1000research.com/", "name": "Home" } }, { "@type": "ListItem", "position": "2", "item": { "@id": "https://f1000research.com/browse/articles", "name": "Browse" } }, { "@type": "ListItem", "position": "3", "item": { "@id": "https://f1000research.com/articles/12-747/v2", "name": "Adsorption of Pb (II) ions on variable charge oxidic calcined substrates..." } } ] } Home Browse Adsorption of Pb (II) ions on variable charge oxidic calcined substrates... ALL Metrics - Views Downloads Get PDF Get XML Cite How to cite this article Prato JG, Millán F, Rangel M et al. Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.12688/f1000research.132880.2 ) NOTE: If applicable, it is important to ensure the information in square brackets after the title is included in all citations of this article. Close Copy Citation Details Export Export Citation Sciwheel EndNote Ref. Manager Bibtex ProCite Sente EXPORT Select a format first Track Share ▬ ✚ Research Article Revised Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] José G. Prato https://orcid.org/0000-0001-8381-404X 1,2 , Fernando Millán 3 , Marialy Rangel 3 , [...] Andrés Márquez 3,4 , Luisa Carolina González https://orcid.org/0000-0002-4431-965X 5 , Iván Ríos 1 , César García https://orcid.org/0000-0002-7561-7473 6 , Carlos Rondón 7 , Enju Wang 8 José G. Prato https://orcid.org/0000-0001-8381-404X 1,2 , Fernando Millán 3 , [...] Marialy Rangel 3 , Andrés Márquez 3,4 , Luisa Carolina González https://orcid.org/0000-0002-4431-965X 5 , Iván Ríos 1 , César García https://orcid.org/0000-0002-7561-7473 6 , Carlos Rondón 7 , Enju Wang 8 PUBLISHED 28 Mar 2024 Author details Author details 1 Grupo de Investigación Estudios Interdisciplinarios, Ingeniería Ambiental, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, Chimborazo Province, 060103, Ecuador 2 Escuela de Ingeniería Química, Facultad de Ingeniería, Universidad de Los Andes, Mérida, 5101, Venezuela 3 Chemical Engineering School, Polytechnical Institute Santiago Mariño, IUPSM-Mérida, Mérida, 5101, Venezuela 4 Facultad de Farmacia y Bioanálisis, Universidad de Los Andes, Mérida, 5101, Venezuela 5 Grupo de Investigación “Análisis de Muestras Biológicas y Forenses”, Laboratorio Clínico, Facultad de Ciencias de la Salud, Universidad Nacional de Chimborazo, Riobamba, Chimborazo Province, 060103, Ecuador 6 Arquitectura, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, Chimborazo Province, 060103, Ecuador 7 Departamento de Química, Facultad de Ciencias, Universidad de Los Andes, Mérida, 5101, Venezuela 8 Department of Chemistry, Saint John´s University, Jamaica, NY, 11439, USA José G. Prato Roles: Conceptualization, Formal Analysis, Investigation, Methodology, Project Administration, Validation, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing Fernando Millán Roles: Conceptualization, Data Curation, Formal Analysis, Investigation, Methodology, Project Administration, Supervision, Validation, Writing – Original Draft Preparation, Writing – Review & Editing Marialy Rangel Roles: Data Curation, Formal Analysis, Investigation, Supervision, Validation Andrés Márquez Roles: Formal Analysis, Investigation, Supervision, Validation, Writing – Original Draft Preparation, Writing – Review & Editing Luisa Carolina González Roles: Conceptualization, Data Curation, Methodology, Project Administration, Supervision, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing Iván Ríos Roles: Formal Analysis, Supervision, Validation, Writing – Original Draft Preparation César García Roles: Data Curation, Formal Analysis, Investigation, Supervision, Validation Carlos Rondón Roles: Conceptualization, Formal Analysis, Funding Acquisition, Investigation, Methodology, Supervision, Validation Enju Wang Roles: Formal Analysis, Investigation, Methodology, Supervision, Validation, Writing – Original Draft Preparation OPEN PEER REVIEW DETAILS REVIEWER STATUS Abstract Background The paper describes lead ion adsorption on variable charge oxidic calcined substrates with chemically modified surfaces. Amphoteric oxides of iron, aluminum, titanium, and manganese, change their surface electric charge after acid or alkaline treatment, letting cationic or anionic adsorption reactions from aqueous solutions. This property allows using them as adsorbing substrate for heavy metals retention in water treatment systems. Methods Substrate was prepared by extruding cylindrical strips from a saturate paste of the oxidic lithological material-OLM; dries it up and thermally treated by calcination. The study was performed by triplicated trial, on batch mode, using 2 grams samples of treated with NaOH 0.1N and non-treated substrate. Lead analysis was performed by AAS-GF. Freundlich and Langmuir models were used to fit results. Comparing differential behavior between treated and non-treated substrates showed the variable charge nature of the OLM. Results Results show L -type isotherms for the adsorption of Pb(II) ions on the activated substrate, suggesting good affinity between Pb(II) ions and OLM’s surface. Average value of adsorption capacity ( K ) for activated substrate (1791.73±13.06), is around four times greater than the non-activated substrate (491.54±31.97), during the adsorption reaction, 0.35 and 0.26 mmolH+ of proton are produced on the activated and non-activated substrate respectively using a 1 m M Pb(II) solution and 72.2 and 15.6 mmolH+ using a 10 m M Pb(II) solution. This acidification agrees with the theoretic model of transitional metals chemisorption on amphoteric oxides, present in lithological material used for the preparation of adsorbent substrates, confirming the information given by the L -type isotherms. Conclusions Results suggest that these variable charge oxidic adsorbent substrate show great potential as an alternative technique for water treatment at small and medium scale using granular filtration system. The easiness and low price make them suitable to apply in rural media where no treating water systems is available. READ ALL READ LESS Keywords ionic adsorption, calcined substrate, Pb(II) ions, isotherms Corresponding Author(s) José G. Prato ( [email protected] ) Fernando Millán ( [email protected] ) Close Corresponding authors: José G. Prato, Fernando Millán Competing interests: No competing interests were disclosed. Grant information: The author(s) declared that no grants were involved in supporting this work. Copyright: © 2024 Prato JG et al . This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. How to cite: Prato JG, Millán F, Rangel M et al. Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.12688/f1000research.132880.2 ) First published: 26 Jun 2023, 12 :747 ( https://doi.org/10.12688/f1000research.132880.1 ) Latest published: 28 Mar 2024, 12 :747 ( https://doi.org/10.12688/f1000research.132880.2 ) Revised Amendments from Version 1 The revised version incorporates the corrections proposed by the three reviewers. The summary, introduction, methodology and references have been modified. Based on these suggestions, we have refined the discussion of results and incorporated conclusions, thus improving the clarity and coherence of the manuscript. These modifications have a significant impact on the precision of our research on the applications of oxidic lithological materials in the treatment of contaminated water, especially in low and middle income communities. The revised version incorporates the corrections proposed by the three reviewers. The summary, introduction, methodology and references have been modified. Based on these suggestions, we have refined the discussion of results and incorporated conclusions, thus improving the clarity and coherence of the manuscript. These modifications have a significant impact on the precision of our research on the applications of oxidic lithological materials in the treatment of contaminated water, especially in low and middle income communities. See the authors' detailed response to the review by Wei Wang See the authors' detailed response to the review by Titus Chinedu Egbosiuba See the authors' detailed response to the review by Nicolae Dinca READ REVIEWER RESPONSES Introduction “ Lithologic materials ” are all those materials belonging to the Earth crust that cannot be classified as soil. However, some of these materials behave as arid soils basically composed by refractory aluminum and iron oxides among other crystalline phases as quartz and clays, they are called “Oxidic Lithologic Material”, OLM. 1 , 2 The two most important properties of these kinds of materials are the thermal resistance and their amphoteric behavior. 2 , 3 In alkaline medium the oxides deprotonate, to create surface negative charges while in acidic medium the oxides protonate, to create surface positive charges. In the first case it favors the cationic adsorption while the second one it favors the anionic adsorption. 2 , 4 – 7 Their thermal resistance allows the preparation of an adsorbent granular medium for water treatment at low cost. As an example of the usefulness of such kind of calcined oxidic substrate could be the removing of heavy metals from water. Lead (Pb) is one of the top ten toxic substances with a great distribution in the environment, 8 , 9 it reaches water sources through various anthropogenic activities such as leaded pipe corrosion or non-treated industrial wastes, as ceramics factories industrial mining activities, oil refining, fossil fuels combustion, frosted lead paints, accumulators manufacturing, among other industrial activities, 9 , 10 leaded fuels are still used in many South America countries, with great environmental impact. 11 Lead pipes have been used for water supply network until the seventies however, old constructions still remain and new residential buildings contain plumbing devices for water services. 12 , 13 Recently lead-contaminated water in some High Schools in Brooklyn, New York has been detected at high concentrations, exceeding the Environmental Protection Agency’s (EPA’s) action level of 0.015 mg/L. 12 Depending on the local water characteristics, such as p H, hardness and temperature, the lead in the pipes and faucets can dissolve, becoming a health risk for the consumers. 13 Lead intake in human being can take place basically via ingests, food or water or breathing, dust in the air might serve as a transport media for lead to travel. 9 , 12 Lead is especially harmful for kids, it accumulates in the soft tissues and bonds, being difficult to eliminate. After accumulation, lead attacks the brain and the central nervous system, with permanents sequels. One of these consequences is the child development delay and cognitive disability. 13 The conventional methods for removing heavy metals from water and sewage have been well described in literature. There are a great variety of methods including chemical precipitation, 8 – 10 ion exchange, 8 , 9 reverse osmosis, 10 membrane processes, 14 photocatalysis, 15 microbial biotechnology, 8 , 9 coagulation, 16 – 18 flocculation, 10 filtration 17 and adsorption technology. 14 – 17 Some of them, such as precipitation, coagulation and sedimentation have disadvantages of generating sludge that requires further treatment, which increases operational costs. 14 , 16 – 18 Ion exchange, reverse osmosis, membrane processes are expensive, need technical assistance for maintenance and few supply companies can offer such kind of systems. 8 – 10 Of all these methods, adsorption technology is one of the most commonly used treatment method due to its advantages: ease to operate, regeneration potentials, lack of sludge formation, inertness to materials and relative low cost. 9 , 10 , 18 , 19 A great variety of adsorbents have been tried and studied, different types of biomass and organic adsorbents as agricultural by-products and its conversion to activated carbon, 16 – 18 , 20 biopolymers, 17 , 21 fungal biomasses have been used with 80 to 100 % percentage retention. 22 Rice straw derived biochar have been used as amendment in soils for Pb immobilization, avoiding its run off through the soil and protect the rivers. 23 The use of Nanomaterials for adsorption processes have been widely reported, their physicochemical properties as small size and large surface area, make them suitable for water treatment systems. Amorphous nanoaluminophosphates have been used for lead retention from aqueous solution with yield between 40 and 70%, 24 diverse carbon nanotubes technologies have been tried for the adsorption of various hazardous metals as As, Cd, Pb, Cr, Ni, Cu, Zn, with adsorption capacities up to 500 mg Pb(II)/g. 10 , 14 , 18 However, most of these methods, are expensive, less available or difficult application at medium and large scale. In previous studies some oxidic lithologic materials, OLM have been characterized with the purpose of preparing calcined adsorbent substrates for ionic adsorption from aqueous solution. 1 , 2 , 25 , 26 The high content of amphoteric iron and aluminium, as well as titanium and manganese oxides, with p H dependent variable charges surfaces, make them suitable for ionic adsorption. 2 , 5 , 7 As a consequence of this particular property, these OLM materials are versatile for preparing a calcined adsorbing substrate using thermal treatment of calcination. Positive or negative charges density is achieved by alkaline or acid treatment, alkaline treatment causes oxide deprotonation creating a negative charge density while acid attack causes oxide protonation, creating a positive charge density on the oxide surface. Such kind of substrate has been applied in water softening, 25 , 27 , 28 suggesting that alkaline and alkaline-earth metals participate in cationic exchange reactions. Other studies suggest that transitional metals as copper, zinc and chrome participate in chemisorption reactions. 1 , 29 , 30 These studies suggest that other transitional metals may also participate in similar kind of specific adsorption reaction. 2 , 6 Residual water treatment and organic matter removing also have been studied. 3 , 31 This study reports a 60-85% reduction in turbidity units, 95-98% reducing biological oxygen demand as well as 88-94% reducing chemical oxygen demand. After acid treatment, the calcined substrate has also been applied in anionic adsorption studies as sulphate and phosphate adsorption. 2 , 32 , 33 All these studies have confirmed that adsorption reaction is more efficient and better defined on the treated substrate than on non-treated substrate. The chemical treatment modifies the surface charge and creates a more homogenous distribution of sites suitable for adsorption. Based on the previous findings, the main objective of the present study is to apply this new kind of substrate in the study of the relative affinity between the Pb(II) ions and the oxidic calcined surface, in order to use it as a granular medium for water treatment. Methods Reagents All the reagents used in the experimental phase are analytical grade, Merck reagent: (CH 3 COO) 2 Pb, NaOH, HCl and distillate water. Oxidic lithological material A 5 kg sample of the raw OLM was collected from a natural deposit, located at the coodinates 8°28′47″ N and 71°23′47″ W. This is an arid zone, where the temperature varies fom 17 to 30 °C, along the year and maximum rainfall of 200 mm per year. The OLM have been previously characterized and the results are reported in the literature. 1 , 2 , 25 , 26 , 28 A brick-red colored sandy loam material with relative low exchange capacity and very low organic material content. Important metallic content: Al (11.75 %), Fe (7.24 %), Ti (0.37%) and Mn (0.03%) are the major metals, 1 these metals are present as refratory amphoteric oxides. Alkaline and alkaline earth content between 0.01 and 1%, with Na (0.86%) and K (1.62%) and very few Ca (0.032%) and Mg (0.31%) content. 26 Several transitoal metals as traces. Due to its thermal resistence, this OLM is used by potters for preparing bricks by thermal treatment. Preparation of the adsorbent substrate and activation of negative surface charges The OLM was crushed using a rubber hammer to avoid the destruction of the mineral structures, sieved for 5 min, using an Octagon 200CL Digital Sieve Shaker (Endecotts Ltd, England) to obtain particle-size fractions of 800 μm, then mixed with distillated water in order to obtain a homogeneous saturated paste easily moldable. 3 mm diameter cylindrical strips were extruded with the a 60 mL syringe, cut into 5 mm long pieces in order to prepare a granular medium (Average diameter: 3.52 ± 0.28 mm, average length: 5.43 ± 0.66 mm, pellet average volume: 51.29 ± 1.70 mm 3 ). The drying process takes place in two steps, for the first step, the granular substrate is air dried for 24 hours, in the second one the substrate is oven drying during another 24 hours, using an oven FELISA FE-293, Jalisco, Mexico, at 150 °C. These two drying steps assure the total elimination of water from the substrate. If there is occluded water it will explode during the calcination process, and might destroy the substrate pellets. Finally, the dried solid substrate is calcined up to 750 °C for four hours in a Thermolyne FB141OM furnace, Thermo Scientific, Waltham, USA, and then cooled down for 12 hours, until 20 °C, before opening the furnace door. The calcination process favors the oxides formation, at such a high temperature, oxygen is very reactive, reacting with the metal to form oxides. Also favor the cementation of the pellets, avoiding dispersion in the aqueous solution. Finally, during the calcination process, organic matter fraction, which is very small, is complete burned out, so only the oxidic phase participates in the adsorption reaction. However, during calcination process the specific surface might be reduced. The calcined substrate is chemically treated in alkaline media with 0.1 N NaOH solution for 12 hours in a flask at room temperature. The alcaline causes the deprotnation of the oxides, enhancing the negative charge density on the surface, allowing the cationic adsorption. The chemically treated substrate is labeled as activated substrate and the non-treated substrate is labeled as non-activated substrate. After chemical treatment, the substrate is washed out with distilled water until neutral p H, then oven dried at 120 °C for 12 hours. The calcined substrate is saturated with distilated water before adsorption, to asure the ionic mobility and reach equiilibium faster. Adsorption studies The adsorption study was performed in triplicated trial, in isothermal conditions (20 ± 2 °C) using batch equilibration procedure, treating seven samples of 2 g of activated and non-activated calcined substrate, with increasing aliquots of 5, 10, 15, 20, 25, 30 and 40 mL from the 1 m M Pb(II) solution, for 24 h. Suspensions were periodically shaken every hour. Differences between C i and C eq were assumed to be due to adsorption. Adsorption isotherms were obtained by plotting the amount of lead adsorbed ( q e ), against the Pb(II) equilibrium concentration ( C eq ) and fitted to the linear forms of the Freundlich and Langmuir equations. 2 , 9 , 18 , 25 , 34 – 37 Comparison between activated and non actvated substrate will show evidence that the oxide deprotonation reaction by the alkaline treatment on the activated substrate. Freundlich Isotherm is an empirical model which assumes an adsorption process characterized by mulitilayer adsorption on heterogeneous surfaces. The model is described by the equation 1 and the linear form by equation 2 . 2 , 9 , 34 , 35 , 38 A graph representation of log ( q e ) vs log ( C eq ) should be a straight line, with slope equal to 1/ n and intercept equal to log ( K F ): (1) q e = K F ∗ C eq 1 n (2) log q e = log K F + 1 n log C eq where q e is the amount adsorbed per adsorbent weight unit, C eq is the equilibrium concentration of adsorbate in solution after adsorption. K F is the Freundlich constant related to adsorption capacity and n is a constant related to adsorption intensity or energetic homogeneity of active sites of adsorption. n may take values near unity or greater. The lower the value of n is, the lower the energy heterogeneity in the active adsorption sites. The Langmuir model describes a reversible process with the formation of adsorbate monolayers on the adsorbent surface. The nonlinear and linear forms of the Langmuir isotherm are described in Equations (3) and (4) 9 , 10 , 18 , 25 , 37 : (3) q e = k 1 ∗ k 2 ∗ C eq 1 + k 1 ∗ C eq (4) C eq q e = 1 k 1 ∗ k 2 + C eq k 2 where k 1 is the Langmuir constant related to the affinity between adsorbate and adsorbent and k 2 is the adsorption capacity, which represents the maximum amount of adsorbate in a monolayer. A graph representation of C eq / q e vs C eq should be a straight line, with slope equal to 1/ k 2 and intercept equal to 1/( k 1 * k 2 ). k 2 and k 1 are determined by the straight line from the slope and the intercept respectively. Values of k 1 and k 2 are then introduced in equation (4) to determine the calculated value of calculated q e and then compared with experimental value. The best fit between the isotherm function and the experimental data was verified through linear regressions of the isotherm linear equation. The fitting of the isotherms was verified through the comparison of the experimental ( q e exp) and calculated ( q e calc) value obtained from the isotherm equation, by means of the linear correlation between the two values, given by the linear regression coefficient ( r ). Lead analysis Pb(II) analyses were performed by AASGF, using a Varian Graphite Furnace Atomic Absorption Spectrophotometer, Spectra AA Zeeman 220 (Palo Alto, California, USA), with a pyrolytic coated graphite tube and Zeeman background corrector. The spectrophotometer is coupled to a Varian auto sampler model EL-97113008. A Varian Uranium hollow cathode lamp was used and measured at 283.3 nm. p H and electric conductivity studies Solution p H and electric conductivity (EC) were measured by triplicate trial, using the same isothermal batch equilibration. p H was measured with a HI 211 p Hmeter (HANNA instruments, Smithfield, Rhode Island, USA), calibrated with commercial buffer solutions of p H 4 and 7. EC was measured with a Trans Instrument HC3010 Conductimeter (Petro Centre, Bukit Merah, Singapure), calibrated with standard reference. All experimental data 39 was managed with the Excel software (Microsoft, Los Angeles, USA). Results Isotherm graph Figure 1a shows by triplicated trial, the adsorption isotherms of Pb(II) ions on the activated and non-activated substrates. Lead adsorption on the activated substrate follow an L -Type isotherm model, while the adsorption on the non-activated substrate looks more like a linear model. Figure 1b shows linear fitting of adsorption data to the Freundlich model. Table 1 shows the fitted equations according to the Freundlich model, as well as parameters r , K F , and n values for activated and non-activated substrates, by triplicated trials. r values look more favorable for the activated substrate, K F value (1791.73 ± 13.06 RSD 0.72%) is about 4 times greater than the respective K F value for the non-activated substrate (491.54 ± 31.97 RSD 6.5%). Similarly, the n values suggest greater adsorption intensity on the activated substrate in relation to the non-activate substrate. Figure 1. a : Isotherms for Pb(II) ions adsorption and b : fitting to the logarithmic form of the Freundlich model for the activated and non-activated substrates. Table 1. Freundlich model parameters, r , K F , and n values for activated and non-activated substrates, by triplicated. Substrate Fitted equation r K F n Activated y = 3.2523 + 0.3446 x 0.9733 1787.72 2.9 y = 3.2568 + 0.3294 x 0.9713 1806.34 3.0 y = 3.2507 + 0.3366 x 0.9497 1781.15 3.0 Non-activated y = 2.7061 + 0.5998 x 0.9098 508.28 1.7 y = 2.6577 + 0.6434 x 0.9423 454.67 1.6 y = 2.7090 + 0.6052 x 0.9268 511.68 1.7 Figure 2 shows the correlation between calculated and experimental q e data for the activated and non-activated substrates and Table 2 shows fitted equations for the linear functions. For the activated substrate, calculated values of q e are biased from the experimental data about 15.16 ± 6.63% and 17.41 ± 18.15% for the non-activated substrate. Figure 2. Correlations between calculated and experimental values of q e (Freundlich model) for the activated and non-activated substrates. Table 2. Fitted equations for the correlation between q e calculated and q e experimental (Freundlich model). Substrate Fitted equation r Activated y = − 270.63 + 1.1222 x 0.9858 Non-activated y = 44.206 + 0.9671 x 0.9893 Figure 3 shows fitting of adsorption data according to the Langmuir model and Table 3 shows fitted equations, r , k 1 and k 2 values for the activated and non-activated substrates, by triplicated. r values are more favorable for the activated substrate than in the non-activated substrate. The k 1 value for the activated substrate is about 20 times greater than for the non-activated substrate. Figure 3. Fitting isotherms to the linear form of the Langmuir equation for the activated and non-activated substrates. Table 3. Langmuir model parameters, r , k 1 and k 2 values for activated and non-activated substrates, by triplicated. Substrate Fitted equation r k 1 k 2 Activated y = 0.0003 + 0.0002 x 0.9937 0.6667 5000 y = 0.0003 + 0.0002 x 0.9945 0.6667 5000 y = 0.0003 + 0.0002 x 0.9950 0.6667 5000 Non-activated y = 0.0034 + 0.0001 x 0.7993 0.0294 10000 y = 0.0034 + 0.0001 x 0.8638 0.0294 10000 y = 0.0032 + 0.0001 x 0.8578 0.0294 10000 Figure 4 show the correlations between calculated and experimental values of q e for the activated and non-activated substrates and Table 4 shows fitted equations for the linear functions. Calculated values of q e are even more biased from the experimental data compared with the Freundlich model. For the activated substrate the average difference is about 25.29 ± 23.67% and 27.22 ± 16.02% for the non-activated substrate. Figure 4. Correlations between calculated value of C ad vs experimental value (Langmuir model) for the activated and non-activated substrates. Table 4. Correlations between calculated and experimental value of q e (Langmuir model) for the activated and non-activated substrates. Substrate Fitted equation r Activated y = − 365.81 + 1.0936 x 0.9809 Non-activated y = − 221.28 + 1.1581 x 0.9784 p H and electric conductivity study Figure 5 shows by triplicated trial, p H variation during adsorption reaction, as a function of mmol of Pb(II) added to the activated, non-activated substrate and raw material, using a 1 m M Pb(II) ions solution. In all cases adsorption reaction take place with solution acidification. Experiments are highly reproducible, so reaction follows the same mechanism in all the replicates. Figure 5. p H variation, by triplicate, as a function of mmol of Pb(II) added to 2 g of substrate from a 1 m M Pb(II) solution, for raw material, and activated and non-activated substrate. Figure 6 shows by triplicate, the relative comparison of p H variation, for all these three cases. The acidification is higher on the activated substrates than in the non-activated substrate or in the raw material, so there are more active sites for the adsorption reaction to occur, with a higher production of protons. Figure 6. p H variation, by triplicate, as a function of mmol of Pb(II) added to 2 g of substrate from a 1 m M Pb(II) solution, for raw material, activated and non-activated substrate. Table 5 shows initial and final concentrations of H + ions during the adsorption reaction of Pb(II) ions and the net amount of mmol of H + ions produced in the whole reaction, when a 1 m M Pb(II) solution is used. Adsorption reaction on the activated substrate produces 0.35 μmol of H + ion, compared with the 0.26 μmol of H + on the non-activated substrate, while raw material produces 0.29 μmol of H + . Table 5. mmol of H + ion produced during the reaction of adsorption when a 1 m M Pb(II) solution is used. Material C i H + mmol/mL mmol 5 mL C f H + mmol/mL mmol 50 mL mmol H + produced RM 3.63 x 10 -8 1.82 x 10 -7 5.89 x 10 -6 2.95 x 10 -4 2.94 x 10 -4 NAS 3.16 x 10 -6 1.58 x 10 -5 5.24 x 10 -5 2.62 x 10 -3 2.60 x 10 -3 AS 6.76 x 10 -7 3.38 x 10 -6 6.91 x 10 -5 3.46 x 10 -3 3.45 x 10 -3 Figure 7 shows EC, variation, by triplicate, during adsorption reaction of Pb(II) ions on the activate and non-activated substrates, as well as on the raw material, using a 1 m M Pb(II) solution. EC in the solution is basically produced by ions in the solution, i.e., CH 3 COO - and Pb(II) ions, as well as H + ions produced in the adsorption reaction. As EC decreases, it suggests that Pb(II) ions are adsorbed on the substrate surface, as well as on the raw material. The adsorption reaction produces ion immobilization being unable to make a net contribution to the EC of the solution. Figure 7. EC variation, by triplicate, as a function of mmol of Pb(II) added to 2 g of substrate from a solution 0.001 M Pb(II), for crud material, activated and non-activated substrate. Figure 8 shows a comparative view of the EC of the solutions for all three cases when a 1 m M Pb(II) solution is used. Although conductivity decrease due to adsorption of Pb(II) ions, solution in contact with activated substrate present greater conductivity due to the highest production of H + ions during the adsorption reaction. These H + ions have a net contribution to the EC of the solution producing an increasing of the conductivity in the solution which is in contact with the substrates. Figure 8. EC variation, by triplicate, as a function of mmol of Pb(II) added to 2 g of substrate from a solution 1 m M Pb(II), for crud material, activated and non-activated substrate. Figure 9 shows p H variation, by triplicate trial, during adsorption reaction of Pb(II) ions on activate and non-activated substrates as well as on the raw material, when using a 10 m M of Pb(II) ions solution. In line with previous instances, the reaction induces the acidification the solution, a phenomenon concurrently escalating with the rise in Pb(II) ion concentration. Figure 9. p H variation, by triplicate, as a function of mmol of Pb(II) added to 2 g of substrate from a 10 m M Pb(II) solution, for raw material, and activated and non-activated substrate. Figure 10 shows comparative p H variations during adsorption reaction for all these three cases, when a 10 m M of Pb(II) solution is used. Acidification process is more accentuated on the activated substrate, as is expected. The experiments are highly reproducible as in the previous case ( Figure 9 ), so reaction takes place through the same mechanism in all the replicates. Figure 10. p H variation as a function of mmol of Pb(II) added to 2 g of substrate from a solution 10 m M Pb(II), for crud material, activated and non-activated substrate. Table 6 shows initial and final concentrations of H + ions during the adsorption reaction of Pb(II) ions and the net amount of mmol of H + ions produced in the whole reaction, when a 10 m M Pb(II) solution is used. Adsorption reaction on activated substrate produces 72.2 μmol of H + ion compared with 15.6 μmol of H + on non-activated substrate, which is almost five times smaller. Adsorption reaction on raw material produces 23.3 μmol of H + ion, which is 3 times smaller than in the case of adsorption reaction on the activated substrate. Moreover, this amount of H + ions is almost 200 times greater than in the former case when used a 1 m M Pb(II) solution for adsorption reaction. Table 6. mmol of H + ion produced during the reaction of adsorption when a 10 m M Pb(II) solution is used. Material C i H + mmol/mL mmol 5 mL C f H + mmol/mL mmol 50 mL mmol H + produced RM 2.95 x 10 -5 1.47 x 10 -4 4.68 x 10 -4 0.0234 0.0233 NAS 3.72 x 10 -5 1.86 x 10 -4 3.16 x 10 -4 0.0158 0.0156 AS 3.55 x 10 -5 1.77 x 10 -4 1.45 x 10 -3 0.0723 0.0722 Figures 11 and 12 shows EC, variation by triplicate, during adsorption reaction of Pb(II) ions on raw material and non-activated and activates substrates, when a 10 m M Pb(II) is used. EC in the solutions decreases, because Pb(II) ions are adsorbed on the substrate’s surfaces, however, the decreasing of EC is less pronounced in the solution in contact with the activated substrate A higher net production of protons rises the EC in the solution. Solutions in contact with the non-activated substrate and the raw material show lower EC values due to the less production of H + ion during the adsorption reaction. Figure 11. EC variation as a function of mmol of Pb(II) added to 2 g of substrate from a solution 10 m M Pb(II), for crud material, activated and non-activated substrate. Figure 12. EC variation as a function of mmol of Pb(II) added to 2 g of substrate from a 10 m M Pb(II) solution, for raw material, activated and non-activated substrate. Discussion As pointed out earlier, the amphoteric oxides of Fe, Al, Mn and Ti present on the oxidic substrate surface, which can modify surface charges according to p H value. In alkaline media, a deprotonation reaction of the oxides take place, increasing surface negative charge density, while in acid media, surface oxide protonation occur, increasing positive charge density according to equation (5) 4 , 7 , 40 : (5) H 2 O + FeO − ← OH − Fe − OH → H + Fe − OH 2 + These materials can be classified as “ Variable Charge Oxidic Lithologic Materials ”. This particular property can be applied in ionic adsorption processes and exploited in water treatment for water softening, or removing of pollutant chemical species as heavy metals. Literature suggests a mechanism for the adsorption of transitional metals, on these kinds of surfaces, through the formation of an inner sphere complex between metal ion and the oxidic surface, according to the equation (6) 4 , 25 , 41 : (6) > FeOH − 1 / 2 + MH 2 O 6 + n → > Fe − O − MH 2 O 5 + n − 3 / 2 + H 3 O + Such a kind of reaction modifies surface charge by increasing the positive charge density, with the formation of H 3 O + ion, producing solution acidification. This kind of adsorption is defined as specific adsorption or chemisorption, presenting great tendency to irreversibility. 4 , 5 Although it does not confirm information about the interaction between Pb(II) ions and calcined substrate surface, an L -type isotherm is indicative of great affinity between Pb(II) ions and calcined substrate surfaces. 36 , 37 , 41 , 42 It might suggests that adsorption reaction on the activated substrate take place through chemisorption of Pb(II) ions on the oxidic surface. At low equilibrium concentrations, the adsorbed amount increases rapidly, while at high concentrations it decreases, reaching to a saturation zone. The adsorption phenomenon is faster and more intensive on the activated substrate because more favorable sites for adsorption are available on the adsorbent substrate surface, according to reaction (5) . Therefore, the probability for the Pb(II) ion adsorption is greater on the activated substrate than on the non-activated substrate. The flat part of the isotherm ( Figure 1a , activated substrate ) suggests formation of a saturated monolayer of Pb(II) ions on the surface as is predicted by the Freundlich and Langmuir models and chemisorption should occur on a single monolayer. This type of isotherm, points to the formation of a covalent bond between Pb(II) ions and the substrate surface that is formed by amphoteric metallic oxides as iron, aluminum, titanium and manganese oxides with variable surface charges. 1 , 2 , 5 , 6 Similar type of isotherm has been reported in the literature for Cu(II) ions on OLM calcined substrates. 6 , 29 , 41 – 44 However, the Langmuir model has its own limitations when used to explain the adsorption process on non-homogeneous surfaces. This model was developed for gas adsorption on homogeneous surfaces; therefore, the model might fail when adsorption take place on irregular surfaces as on the oxidic adsorbent substrate. One of the disadvantages of the Langmuir model is to assume the formation of a monolayer on a homogeneous surface, where all the available sites for the adsorption are equivalent and the ΔH ad is independent of the degree of surface coverage. However, on a non-homogeneous or irregular surface the adsorption sites are non-equivalent and the ΔH ad varies from one place to another. Consequently, those places which led to a more stable bonding are first occupied. The interaction between adsorbed molecules might affect the affinity between the adsorbate and adsorbent, and the greater the surface coverage is, the smaller the ΔH ad is also increases the repulsion between the adsorbed molecules. It might cause the mobility of the molecules through the surface and different places can be occupied. As a result, a physisorbed layers can be formed over the chemisorbed layer. 35 , 36 , 40 – 42 On the contrary Freundlich model adapts better to non-homogeneous surfaces, consequently, the adsorption from aqueous phase on non-homogeneous or irregular surfaces like the calcined substrate surface, the Freundlich model fits better. 2 , 35 – 37 , 41 On the non-activated substrate Adsorption reaction ( Figure 1 a ), it seems to run by two different mechanisms. At lower concentrations it follows an L -type isotherm, showing much less affinity for Pb(II) ions compared to activated substrate, the smallest negative charge density on the surface is a limiting factor for the adsorption of Pb(II) ion. However, at higher concentrations, adsorption follows a linear model, suggesting a collateral mechanism for the Pb(II) ions adsorption. Most likely acetate ions, being strong base, might act as a deprotonation agent in favor of the adsorption of Pb(II) ions, according to the reaction (7) : (7) FeOH + C H 3 CO O − → Fe O − + C H 3 COOH Therefore, adsorption of Pb(II) ions take place after oxide deprotonation via acetate ion, according to a multilayer physic adsorption model. After all, acetate ions, being a strong base, might compete in the oxide deprotonation to form molecular acetic acid. However, the acetate effect doesn’t appear on the activated substrate because the oxidic surface is already deprotonate by the previous alkaline attack. As it was pointed out earlier, non-activated substrate data serves only as a reference to confirm the oxides deprotonation reaction after alkaline treatment on the activated substrate, so non-activated substrate is useless without being chemically treated in alkaline medium. The p H measurements during the adsorption reaction showed a significant acidification along the reaction, which agree with the literature 4 , 5 , 38 , 40 , 43 about transitional metals chemisorption on amphoteric surface with variable charge. This acidification process became more intense as the concentration of Pb(II) ions in the solution increases. Along with the L -type isotherm, the acidification might be interpreted in terms of a covalence between Pb(II) ions and the oxidic surface, into a specific adsorption reaction or chemisorption, according to the model presented in the equation 8 suggest by the literature. 1 , 5 , 29 , 44 (8) > M − OH − 0.5 + PbH 2 O 4 + 2 → > M − O − PbH 2 O 3 + 0.5 + H 3 O + Actually, the new negative charges formed during the alkaline reaction of oxides deprotonation are temporally neutralized by sodium ions, from NaOH solution, which finally will be replaced by Pb(II) ions in the adsorption reaction. EC measurements confirm the acidification process, the highest EC values in the solution in contact with the activated substrate might be interpreted in terms of a highest proton production during the adsorption reaction on the activated substrate. According to the results, the adsorption reaction is more favorable on the activated substrate where more adsorption active sites are available, due to the alkaline treatment, which increased and homogenize the negative charge density along the substrate surface. The small negative charge density on the non-activated substrate is a limiting factor for the adsorption to occur. Similar results have been reported for the adsorption of heavy metals (Cu, Cd, Zn, As, Ni, Mn, Hg, Cr) on biomaterials, zeolites, polymers, carbonaceous materials, and activated clay, where the increment of the p H increases the negatively charged sites because the deprotonation reaction the sorbent surface, favoring adsorption phenomena. 6 , 9 , 10 , 14 , 19 , 29 , 37 , 44 Therefore, it is expected that other transitional metals can suffer the kind of reaction on these kinds of oxidic substrates, making possible their retention from contaminated waters during a filtration process in a granular media. For activated substrate, adjustment data by Freundlich and Langmuir models fits well with experimental data; however calculated values are biased from the experimental data 15% for the Freundlich model and 25% for the Langmuir model, most probably because of the lack of homogeneity on the oxidic surface, on the contrary, substrate present a rough and irregular surface. Less homogeneity on the surface means that not all adsorbent positions are equivalent. Therefore, the condition of equivalent adsorption sites is no longer fulfilled. Actually, both models try to explain the same type of isotherm, but Freundlich is an empirical model with less straightening conditions compared to the Langmuir which was developed on valuable ideal theoretical considerations difficult to respect in the case of the calcined substrate. Adsorption isotherms are expressions that define the energy distribution in the active sites and the heterogeneity of the adsorbent surface. This is why when different types of materials and experimental conditions are used, the isotherm can vary. In general, the Langmuir and Freundlich models have been reported that can describe the adsorption process of Pb(II) using clay modified adsorbents, biomaterials, activated carbon, zeolites and multi walled carbon nanotubes. 6 , 10 , 14 , 16 Conclusion The work focused on the study of the adsorption of Pb(II) ions on the variable charge oxidic substrate, prepared from a natural oxidic lithologic material by thermal treatment and chemically treated or activated in alkaline medium, in order to create a homogenous negative surface charge density where Pb(II) ions can be adsorbed. Adsorption described by an L -type isotherm, show great affinity between Pb(II) ions and the activated surface, adjusted to the Freundlich model. The evidence points to the formation of a covalence between the oxidic surface and Pb(II) ion, with solution acidification. p H measurements during the adsorption reaction showed important acidification along the adsorption reaction according with the theoretic model of chemisorption Results suggest that this variable charge oxidic adsorbent substrate have great potential as an alternative technique for water treatment at small and medium scale using granular filtration system. Alkaline and acid treated substrates may be combined to retain cationic and anionic species sequentially. Such kind of system will allow not only water softening but removal of other pollutant as heavy metals, organic matter and important turbidity reducing. The easiness and low price make them suitable to apply in rural media without treating water systems, using a low-cost and reliable adsorption system. Ethical considerations Not applicable. Data availability Underlying data Figshare: Adsorption of Pb(II) ions on Variable Charge Oxidic Calcined Substrates with Chemically Modified Surface https://doi.org/10.6084/m9.figshare.22266772.v2 . 39 This project contains the following underlying data: • Study Adsorption Pb Freundlich model.xlsx • Study Adsorption Pb Langmuir model.xlsx • Study Adsorption Pb H+ produced.xlsx • Study pH Adsorption Pb.xlsx • Study CE Adsorption Pb.xlsx Data are available under the terms of the Creative Commons Deed License (CC0 1.0 Universal) . Acknowledgements The authors give thanks to the Universidad Nacional de Chimborazo for supporting this work through the research projects program References 1. Millán F, Prato JG, García M, et al. : Adsorción de iones Cu +2 y Zn +2 por materiales litológicos de carga variable, provenientes de suelos del estado Mérida, Venezuela. Rev. Téc. Ing. Univ. Zulia. 2013; 36 (3): 195–201. 2. Prato JG, Millán FC, González LC, et al. : Adsorption of phosphate and nitrate ions on oxidic substrates prepared with a variable-charge lithological material. Water. 2022; 14 : 2454. Publisher Full Text 3. Prato J, Millán F, González L, et al. : Evaluación de materiales litológicos oxídicos como adsorbentes para el tratamiento de efluentes y aguas residuales. Novasinergia. 2021; 4 (2): 93–110. Publisher Full Text 4. Qafoku NP, Van Ranst E, Noble A, et al. : Variable charge soils: Their mineralogy, chemistry and management. Adv. Agron. 2004; 84 : 159–215. Publisher Full Text 5. Xu RK, Qafoku NP, Van Ranst E, et al. : Adsorption properties of subtropical and tropical variable soils: Implication from climate change and biochard amendment. Adv. Agron. 2016; 135 : 1–58. Publisher Full Text 6. Gu S, Kang X, Wang L, et al. : Clay mineral adsorbents for heavy metal removal from wastewater: A review. Environ. Chem. Lett. 2019; 17 (2): 629–654. Publisher Full Text 7. Xu R, Wang Y, Tiwari D, et al. : Effect of ionic strength on adsorption of As (III) and As(V) on variable charge soils. J. Environ. Sci. 2009; 21 (7): 927–932. Publisher Full Text 8. Xie Y, Yuan X, Wu Z, et al. : Adsorption behavior and mechanism of Mg/Fe layered double hydroxide with Fe 3 O 4 -carbon spheres on the removal of Pb(II) and Cu(II). J. Colloid Interface Sci. 2019; 536 : 440–455. PubMed Abstract | Publisher Full Text 9. Kaur M, Kumari S, Sharma P: Removal of Pb(II) from aqueous solution using nanoadsorbent of Oryza sativa husk: Isotherm, kinetic and thermodynamic studies. Biotechnol. Rep. 2020; 25 : e00410. PubMed Abstract | Publisher Full Text | Free Full Text 10. Egbosiuba TC, Abdulkareem AS, Tijani JO, et al. : Taguchi optimization design of diameter-controlled synthesis of multi walled carbon nanotubes for the adsorption of Pb(II) and Ni(II) from chemical industry wastewater. Chemosphere. 2021; 266 : 128937. Publisher Full Text PubMed Abstract | 11. Ndungu K, Zurbrick CK, Stammerjohn S, et al. : Lead sources to the Amundsen Sea, West Antarctica. Envirom. Sci. Technol. 2016; 50 (12): 6233–6239. PubMed Abstract | Publisher Full Text 12. Latham S, Jennings JL: Reducing lead exposure in school water: Evidence from remediation efforts in New York city public schools. Environ. Res. 2022; 203 : 111735. PubMed Abstract | Publisher Full Text 13. Wani AL, Ara A, Usmani JA: Lead toxicity: A review. Interdiscip. Toxicol. 2015; 8 (2): 55–64. Publisher Full Text | PubMed Abstract | Free Full Text 14. Egbosiuba TC, Egwunyenga MC, Tijani JO, et al. : Activated multi-walled carbon nanotubes decorated with zero valent nickel nanoparticles for arsenic, cadmium and lead adsorption from wastewater in a batch and continuous flow modes. J. Hazard. Mater. 2022; 423 : 126993. Publisher Full Text PubMed Abstract | 15. Sagadevan S, Fatimah I, Egbosiub TC, et al. : Photocatalytic efficiency of titanium dioxide for dyes and heavy metals removal from wastewater. Bull. Chem. React. Eng. Catal. 2022; 17 (2): 430–450. Publisher Full Text 16. Alghamdi AA, Al-Odayni AB, Saeed WS, et al. : Efficient adsorption of lead(II) from aqueous phase solutions using polypyrrole-based activated carbon. Materials. 2019; 12 (12): 2020. PubMed Abstract | Publisher Full Text | Free Full Text 17. Renu, Agarwal M, Singh K: Heavy metal removal from wastewater using various adsorbents: A review. J. Water Reuse Desal. 2017; 7 (4): 387–419. Publisher Full Text 18. Raji Z, Karim A, Karam A, et al. : Adsorption of heavy metals: mechanisms, kinetics, and applications of various adsorbents in wastewater remediation—A Review. Waste. 2023; 1 (3): 775–805. Publisher Full Text 19. Egbosiuba TC, Abdulkareem AS, Kovo AS, et al. : Enhanced adsorption of As(V) and Mn(VII) from industrial wastewater using multi-walled carbon nanotubes and carboxylated multi-walled carbon nanotubes. Chemosphere. 2020; 254 : 126780. Publisher Full Text 20. Sherugar P, Padaki M, Naik NS, et al. : Biomass-derived versatile activated carbon removes both heavy metals and dye molecules from wastewater with near-unity efficiency: Mechanism and kinetics. Chemosphere. 2022; 287 : 132085. PubMed Abstract | Publisher Full Text 21. Lv QV, Hu X, Zhang X, et al. : Highly efficient removal of trace metal ions by using poly (acrylic acid) hydrogel adsorbent. Mater. Des. 2019; 181 : 107934. Publisher Full Text 22. Enamorado Horrutiner Y, Villanueva Tagle M, Hernández Díaz I, et al. : Caracterización de biomasa inactiva de Aspergillus Niger 0-5 como sorbente de Pb(II). Quím. Nova. 2011; 34 (7): 1141–1146. Publisher Full Text 23. Jiang TY, Jiang J, Xu RK, et al. : Adsorption of Pb(II) on variable charge soils amended with rice-straw derived biochar. Chemosphere. 2012; 89 (3): 249–256. PubMed Abstract | Publisher Full Text 24. Rondón W, Sifontes AB, Freire D, et al. : Remoción de plomo en soluciones acuosas empleando nanoaluminofosfatos amorfos. Rev. Ambient. Água. 2015; 10 (1): 59–70. Publisher Full Text 25. Prato JG, Millán F, Ríos A, et al. : Uso de materiales litológicos oxídicos para la dureza en aguas naturales. Inf. Tecnol. 2022; 33 (2): 145–156. Publisher Full Text 26. Millán F, Zerpa D, Prato JG, et al. : Caracterización química de tres fracciones granulométricas de materiales litológicos oxídicos. In extensu Publication. Proceedings of XXI Congreso de la Sociedad Venezolana de la Ciencia del Suelo. UNET, San Cristóbal.2015. 978-980-6300-94-1. Reference Source 27. Prato JG, González-Ramírez LC, Pérez MC, et al. : Adsorción de la dureza del agua sobre lechos de rocas volcánicas de Ecuador. Inf. Tecnol. 2021; 32 (2): 51–60. Publisher Full Text 28. Millán F, Prato JG, López MA, et al. : Estudio de la retención de iones calcio por materiales térmicamente modificados provenientes de suelos de la región de San Juan de Lagunillas, estado Mérida, Venezuela. Rev. Téc. Ing. Univ. Zulia. 2009; 32 (1): 48–54. 29. Millán F, Prato JG, González L, et al. : Cu +2 chemisorption on calcined substrates made with an oxidic refractory variable charges lithological material. Rev. Téc. Ing. Univ. Zulia. 2019; 42 (1): 10–18. Publisher Full Text 30. Márquez A, Millán F, Prato JG, La Cruz C: Adsorción de iones Cr(VI) sobre lechos adsorbente calcinados con superficie de carga variable químicamente modificada. Rev. Téc. Ing. Univ. Zulia. 2020; 43 (2): 72–81. Publisher Full Text 31. Millán F, Prato JG, Montilla T, et al. : Using of variable charge adsorption beds for filtration of residual waters. Rev. Téc. Ing. Univ. Zulia. 2018; 41 (1): 98–110. 32. Prato JG, Ruiz LB, Djabayan P, et al. : Adsorción de iones fosfatos de aguas naturales a partir de lechos calcinados de suelos lateríticos.Arboleda JR, editor. Investigación y Academia: la Visión desde la Universidad Ecuatoriana. Red Iberoamericana de Pedagogía (REDIPE); 2019; (pp. 133–151). Cap. 8. 33. Prato JG, Navas SA, Ríos AC: Adsorción de iones SO 4 2- en aguas naturales empleando lechos de arcilla amarilla.García VJ, Márquez CO, Giménez E, et al., editors. Avances en Ingeniería 2021 . Ediciones Universidad Nacional de Chimborazo (Unach); 2022; (pp. 205–222). Cap. 9. Publisher Full Text 34. Dahliyanti A, Yunitama DA, Rofiqoh IM, et al. : Synthesis and characterization of silica xerogel from corn husk waste as cationic dyes adsorbent. F1000Res. 2022; 11 (305): 305. PubMed Abstract | Publisher Full Text | Free Full Text 35. Foo KY, Hameed BH: Insights into the modeling of adsorption isotherm systems. Chem. Eng. J. 2010; 156 : 2–10. Publisher Full Text 36. Al-Ghouti MA, Da’ana DA: Guidelines for the use and interpretation of adsorption isotherm models: A review. J. Hazard. Mater. 2020; 393 : 122383. PubMed Abstract | Publisher Full Text 37. Kalam S, Abu-Khamsin SA, Kamal MS, et al. : Surfactant adsorption isotherms: A review. ACS Omega. 2021; 6 : 32342–32348. PubMed Abstract | Publisher Full Text | Free Full Text 38. Gupta A, Sharma V, Sharma K, et al. : A review of adsorbents for heavy metal decontamination: Growing approach to wastewater treatment. Materials. 2021; 14 (16): 1–45. Publisher Full Text | PubMed Abstract | Free Full Text 39. Prato J, Millán F, González Ramírez LC, et al. : Adsorption of Pb(II) ions on Variable Charge Oxidic Calcined Substrates with Chemically Modified Surface. [Data]. Figshare. 2023; 12 Publisher Full Text 40. McBride MB: Environmental chemistry of soils. Oxford: Ed. Oxford Univ; 1994. 41. Adamson A: Physical chemistry of surfaces. 5th ed.England: Wiley Interscience Publications; 1990; pp. 421–426. 42. Masel R: Principles of adsorption and reaction on solid surfaces. England: Wiley Interscience publications; 1996; pp. 235–248. 43. Jiang J, Xu RK, Li SZ: Effect of ionic strength and mechanism of Cu(II) adsorption by Goethite and γ – Al 2 O 3 . J. Chem. Eng. Data. 2010; 55 : 5547–5552. Publisher Full Text 44. Millán F, Prato JG, Zerpa D, et al. : Copper adsorption on calcined substrates from three granulometric fractions coming from two refractory variable charges lithological materials. Int. J. Recent Dev. Eng. Technol. 2017; 6 (8): 7–17. Comments on this article Comments (0) Version 2 VERSION 2 PUBLISHED 26 Jun 2023 ADD YOUR COMMENT Comment Author details Author details 1 Grupo de Investigación Estudios Interdisciplinarios, Ingeniería Ambiental, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, Chimborazo Province, 060103, Ecuador 2 Escuela de Ingeniería Química, Facultad de Ingeniería, Universidad de Los Andes, Mérida, 5101, Venezuela 3 Chemical Engineering School, Polytechnical Institute Santiago Mariño, IUPSM-Mérida, Mérida, 5101, Venezuela 4 Facultad de Farmacia y Bioanálisis, Universidad de Los Andes, Mérida, 5101, Venezuela 5 Grupo de Investigación “Análisis de Muestras Biológicas y Forenses”, Laboratorio Clínico, Facultad de Ciencias de la Salud, Universidad Nacional de Chimborazo, Riobamba, Chimborazo Province, 060103, Ecuador 6 Arquitectura, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, Chimborazo Province, 060103, Ecuador 7 Departamento de Química, Facultad de Ciencias, Universidad de Los Andes, Mérida, 5101, Venezuela 8 Department of Chemistry, Saint John´s University, Jamaica, NY, 11439, USA José G. Prato Roles: Conceptualization, Formal Analysis, Investigation, Methodology, Project Administration, Validation, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing Fernando Millán Roles: Conceptualization, Data Curation, Formal Analysis, Investigation, Methodology, Project Administration, Supervision, Validation, Writing – Original Draft Preparation, Writing – Review & Editing Marialy Rangel Roles: Data Curation, Formal Analysis, Investigation, Supervision, Validation Andrés Márquez Roles: Formal Analysis, Investigation, Supervision, Validation, Writing – Original Draft Preparation, Writing – Review & Editing Luisa Carolina González Roles: Conceptualization, Data Curation, Methodology, Project Administration, Supervision, Visualization, Writing – Original Draft Preparation, Writing – Review & Editing Iván Ríos Roles: Formal Analysis, Supervision, Validation, Writing – Original Draft Preparation César García Roles: Data Curation, Formal Analysis, Investigation, Supervision, Validation Carlos Rondón Roles: Conceptualization, Formal Analysis, Funding Acquisition, Investigation, Methodology, Supervision, Validation Enju Wang Roles: Formal Analysis, Investigation, Methodology, Supervision, Validation, Writing – Original Draft Preparation Competing interests No competing interests were disclosed. Grant information The author(s) declared that no grants were involved in supporting this work. Article Versions (2) version 2 Revised Published: 28 Mar 2024, 12:747 https://doi.org/10.12688/f1000research.132880.2 version 1 Published: 26 Jun 2023, 12:747 https://doi.org/10.12688/f1000research.132880.1 Copyright © 2024 Prato JG et al . This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Download Export To Sciwheel Bibtex EndNote ProCite Ref. Manager (RIS) Sente metrics Views Downloads F1000Research - - PubMed Central info_outline Data from PMC are received and updated monthly. - - Citations open_in_new 0 open_in_new 0 open_in_new SEE MORE DETAILS CITE how to cite this article Prato JG, Millán F, Rangel M et al. Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.12688/f1000research.132880.2 ) NOTE: If applicable, it is important to ensure the information in square brackets after the title is included in all citations of this article. COPY CITATION DETAILS track receive updates on this article Track an article to receive email alerts on any updates to this article. TRACK THIS ARTICLE Share Open Peer Review Current Reviewer Status: ? Key to Reviewer Statuses VIEW HIDE Approved The paper is scientifically sound in its current form and only minor, if any, improvements are suggested Approved with reservations A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit. Not approved Fundamental flaws in the paper seriously undermine the findings and conclusions Version 2 VERSION 2 PUBLISHED 28 Mar 2024 Revised Views 0 Cite How to cite this report: Dinca N. Reviewer Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.163125.r260344 ) The direct URL for this report is: https://f1000research.com/articles/12-747/v2#referee-response-260344 NOTE: it is important to ensure the information in square brackets after the title is included in this citation. Close Copy Citation Details Reviewer Report 02 Apr 2024 Nicolae Dinca , Department of Technical and Natural Sciences, Faculty of Food Engineering, Tourism and Environmental Protection, “Aurel Vlaicu” University, Arad, Romania Approved VIEWS 0 https://doi.org/10.5256/f1000research.163125.r260344 Thanks, the revised form includes all my requests for ... Continue reading READ ALL Thanks, the revised form includes all my requests for improving the work. I have no other comments to make. Competing Interests: No competing interests were disclosed. Reviewer Expertise: chemistry I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. Close READ LESS CITE CITE HOW TO CITE THIS REPORT Dinca N. Reviewer Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.163125.r260344 ) The direct URL for this report is: https://f1000research.com/articles/12-747/v2#referee-response-260344 NOTE: it is important to ensure the information in square brackets after the title is included in all citations of this article. COPY CITATION DETAILS Report a concern Respond or Comment COMMENT ON THIS REPORT Version 1 VERSION 1 PUBLISHED 26 Jun 2023 Views 0 Cite How to cite this report: Chinedu Egbosiuba T. Reviewer Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.145832.r196306 ) The direct URL for this report is: https://f1000research.com/articles/12-747/v1#referee-response-196306 NOTE: it is important to ensure the information in square brackets after the title is included in this citation. Close Copy Citation Details Reviewer Report 03 Nov 2023 Titus Chinedu Egbosiuba , Texas A&M University, College Station, Texas, USA Approved with Reservations VIEWS 0 https://doi.org/10.5256/f1000research.145832.r196306 F1000 Research Review The study reported “Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface ”. The authors prepared oxidic calcined and chemically modified substrates for the removal of Pb (II) ions from wastewater. ... Continue reading READ ALL F1000 Research Review The study reported “Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface ”. The authors prepared oxidic calcined and chemically modified substrates for the removal of Pb (II) ions from wastewater. I recommend the reconsideration of the manuscript for approval after the following comments are addressed: Comments The language of the manuscript must be improved by a native English editor. There are a number of grammatical errors. I suggest the addition of continuous line numbering to enhance review effectiveness. The abstract must be summarized and rewritten to briefly capture the background, aim of the study, methodology, key results, and the main conclusion. Additional quantification of the results in the abstract is recommended. In the introduction, describe the hazardous effects of the Pb(II) ions heavy metals. The suggested literatures can guide the authors. I suggest the addition of more treatment techniques such as photocatalysis, adsorption, advanced oxidation process, membrane filtration. Also, each of the mentioned techniques must be referenced. The recommended literature can guide the authors. 2 nd paragraph: “Amorphous nanoaluminophosphates have also been proved for lead removing from…” I suggest removing be changed to removal. The entire statement must also be rephrased accordingly. How was the OLM chemically characterized and where are the results? Under the preparation of adsorbent, “The lithologic material was crushing…” Crushing or crushed? Why use furnace to dry at 150 o C. Is drying done with furnace or oven? How is oxides formation favored by calcination? Reference please. Kindly remove this statement from the bracket. “(The non-treated...substrate). The suggested literatures can be used to reference the model equations. Be consistent in the use of either Pb(II) ions or Pb +2 . I suggest the removal of grid lines from the graphs. Table 1 and 3 shows the Freundlich and Langmuir isotherm parameters, not fitted equations. Merge Table 1 and 2. Evaluate the qe parameter and present in Table 1. Also merge Table 3 and 4. Under pH and electric conductivity study, “….and activates substrates” Is it activates or activated? There is no conclusion at the end of the manuscript, is that the journal format? I recommend the following references must be added to enrich the manuscript 1 - 18 . Is the work clearly and accurately presented and does it cite the current literature? Yes Is the study design appropriate and is the work technically sound? Yes Are sufficient details of methods and analysis provided to allow replication by others? Yes If applicable, is the statistical analysis and its interpretation appropriate? Yes Are all the source data underlying the results available to ensure full reproducibility? Yes Are the conclusions drawn adequately supported by the results? No References 1. Alex Mbachu C, Kamoru Babayemi A, Chinedu Egbosiuba T, Ifeanyichukwu Ike J, et al.: Green synthesis of iron oxide nanoparticles by Taguchi design of experiment method for effective adsorption of methylene blue and methyl orange from textile wastewater. Results in Engineering . 2023; 19 . Publisher Full Text 2. Kilinc B, Akagunduz D, Ozdemir M, Kul A, et al.: Hydrogen production using cocaine metabolite in microbial electrolysis cells. 3 Biotech . 2023; 13 (11): 382 PubMed Abstract | Publisher Full Text 3. Sagadevan S, Fatimah I, Egbosiuba T, Alshahateet S, et al.: Photocatalytic Efficiency of Titanium Dioxide for Dyes and Heavy Metals Removal from Wastewater. Bulletin of Chemical Reaction Engineering & Catalysis . 2022; 17 (2): 430-450 Publisher Full Text 4. Chukwu Onu D, Kamoru Babayemi A, Chinedu Egbosiuba T, Onyinye Okafor B, et al.: Isotherm, kinetics, thermodynamics, recyclability and mechanism of ultrasonic assisted adsorption of methylene blue and lead (II) ions using green synthesized nickel oxide nanoparticles. Environmental Nanotechnology, Monitoring & Management . 2023; 20 . Publisher Full Text 5. Abdulkareem A, Hamzat W, Tijani J, Egbosiuba T, et al.: Isotherm, kinetics, thermodynamics and mechanism of metal ions adsorption from electroplating wastewater using treated and functionalized carbon nanotubes. Journal of Environmental Chemical Engineering . 2023; 11 (1). Publisher Full Text 6. Egbosiuba T, Abdulkareem A, Kovo A, Afolabi E, et al.: Ultrasonic enhanced adsorption of methylene blue onto the optimized surface area of activated carbon: Adsorption isotherm, kinetics and thermodynamics. Chemical Engineering Research and Design . 2020; 153 : 315-336 Publisher Full Text 7. Aliyu S, Ambali A, Oladejo T, Mustapha S, et al.: Development of Ag-doped on multi-walled carbon nanotubes for the treatment of fish pond effluent. Regional Studies in Marine Science . 2023; 58 . Publisher Full Text 8. Egbosiuba T, Abdulkareem A: Highly efficient as-synthesized and oxidized multi-walled carbon nanotubes for copper(II) and zinc(II) ion adsorption in a batch and fixed-bed process. Journal of Materials Research and Technology . 2021; 15 : 2848-2872 Publisher Full Text 9. Uko C, Tijani J, Abdulkareem S, Mustapha S, et al.: Adsorptive properties of MgO/WO3 nanoadsorbent for selected heavy metals removal from indigenous dyeing wastewater. Process Safety and Environmental Protection . 2022; 162 : 775-794 Publisher Full Text 10. Egbosiuba TC, Abdulkareem AS, Tijani JO, Ani JI, et al.: Taguchi optimization design of diameter-controlled synthesis of multi walled carbon nanotubes for the adsorption of Pb(II) and Ni(II) from chemical industry wastewater. Chemosphere . 2021; 266 : 128937 PubMed Abstract | Publisher Full Text 11. Egbosiuba TC, Egwunyenga MC, Tijani JO, Mustapha S, et al.: Activated multi-walled carbon nanotubes decorated with zero valent nickel nanoparticles for arsenic, cadmium and lead adsorption from wastewater in a batch and continuous flow modes. J Hazard Mater . 2022; 423 (Pt B): 126993 PubMed Abstract | Publisher Full Text 12. Egbosiuba TC, Abdulkareem AS, Kovo AS, Afolabi EA, et al.: Enhanced adsorption of As(V) and Mn(VII) from industrial wastewater using multi-walled carbon nanotubes and carboxylated multi-walled carbon nanotubes. Chemosphere . 2020; 254 : 126780 PubMed Abstract | Publisher Full Text 13. Egbosiuba TC, Abdulkareem AS, Kovo AS, Afolabi EA, et al.: Adsorption of Cr(VI), Ni(II), Fe(II) and Cd(II) ions by KIAgNPs decorated MWCNTs in a batch and fixed bed process. Sci Rep . 2021; 11 (1): 75 PubMed Abstract | Publisher Full Text 14. De Gisi S, Notarnicola M: Industrial Wastewater Treatment. 2017. 23-42 Publisher Full Text 15. Tijani J, Odeh E, Mustapha S, Egbosiuba T, et al.: Photocatalytic, electrochemical, antibacterial and antioxidant behaviour of carbon-sulphur Co-doped zirconium (IV) oxide nanocomposite. Cleaner Chemical Engineering . 2022; 3 . Publisher Full Text 16. Tijani J, Abdullahi M, Bankole M, Mustapha S, et al.: Photocatalytic and toxicity evaluation of local dyeing wastewater by aluminium/boron doped WO3 nanoparticles. Journal of Water Process Engineering . 2021; 44 . Publisher Full Text 17. Pisello A, Kueppers U, Düffels K, Nomikou P, et al.: The porosity of felsic pyroclasts: laboratory validation of field-based approaches. Bull Volcanol . 2023; 85 (11): 69 PubMed Abstract | Publisher Full Text 18. Abubakar HL, Tijani JO, Abdulkareem AS, Egbosiuba TC, et al.: Effective removal of malachite green from local dyeing wastewater using zinc-tungstate based materials. Heliyon . 2023; 9 (9): e19167 PubMed Abstract | Publisher Full Text Competing Interests: No competing interests were disclosed. Reviewer Expertise: Materials synthesis for wastewater treatment, Adsorption studies, Kinetic and Isotherm models, Reusability study and the Mechanism of adsorption studies. I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. Close READ LESS CITE CITE HOW TO CITE THIS REPORT Chinedu Egbosiuba T. Reviewer Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.145832.r196306 ) The direct URL for this report is: https://f1000research.com/articles/12-747/v1#referee-response-196306 NOTE: it is important to ensure the information in square brackets after the title is included in all citations of this article. COPY CITATION DETAILS Report a concern Author Response 13 Apr 2024 JOSE PRATO MORENO , Grupo de Investigación Estudios Interdisciplinarios, Ingeniería Ambiental, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, 060103, Ecuador 13 Apr 2024 Author Response We thank to the reviewer for their comments Comment 1 : The language of the manuscript must be improved by a native English editor. There are a number of grammatical ... Continue reading We thank to the reviewer for their comments Comment 1 : The language of the manuscript must be improved by a native English editor. There are a number of grammatical errors. Response 1: The linguistic aspects of the manuscript in English have undergone a review and necessary corrections. Comment 2 : I suggest the addition of continuous line numbering to enhance review effectiveness. Response 2: The magazine format template does not include continuous numbering in the lines of the manuscript. Comment 3: The abstract must be summarized and rewritten to briefly capture the background, aim of the study, methodology, key results, and the main conclusion. Additional quantification of the results in the abstract is recommended. Response 3: The abstract has been meticulously crafted to align with the stipulated guidelines of the journal (300 words). The information has been expanded following the suggestions given. Notably, the results paragraph incorporates main quantitative data obtained in the research. Comment 4 : In the introduction, describe the hazardous effects of the Pb(II) ions heavy metals. The suggested literatures can guide the authors. Response 4: The introduction has been improved in accordance with the suggestions provided by the reviewer. Comment 5 : I suggest the addition of more treatment techniques such as photocatalysis, adsorption, advanced oxidation process, membrane filtration. Also, each of the mentioned techniques must be referenced. The recommended literature can guide the authors. Response 5: The authors do not intend to provide a comprehensive "state of the art" on lead removal. Nevertheless, we have enhanced the introduction based on the literature recommended by the reviewer. Comment 6 : 2nd paragraph: “Amorphous nanoaluminophosphates have also been proved for lead removing from…” I suggest removing be changed to removal. The entire statement must also be rephrased accordingly. Response 6: The suggested change has been made. Comment 7 : How was the OLM chemically characterized and where are the results?. Response 7: The OLM has undergone both physical and chemical characterization, with the results referenced in the cited literature. However, the authors have chosen to incorporate some of these findings into the methodology section. Comment 8 : Under the preparation of adsorbent, “The lithologic material was crushing…” Crushing or crushed?. Response 4: Correction, the word is “crushed”. Comment 9 : Why use furnace to dry at 150 ºC. Is drying done with furnace or oven?. Response 9: The drying process occurs in two steps: first, air drying for 24 hours, followed by oven drying for an additional 24 hours. These sequential drying steps ensure the complete removal of water from the substrate. Any residual occluded water in the pellet maybe a risk of explosion during the calcination process, leading to the destruction of the pellet. Comment 10 : How is oxides formation favored by calcination?. Response 10: Throughout thermal treatment, oxygen exhibits high reactivity, making surface oxidation the most likely reaction in the substrate. This process is a routine procedure for oxide formation in laboratory settings. “Brett NH. (1991). Magnesium and Alkaline-Earth Oxides. Concise Encyclopedia of Advanced Ceramic Materials. https://doi.org/10.1016/B978-0-08-034720-2.50080-0”. Comment 11 : Kindly remove this statement from the bracket. “(The non-treated...substrate). Response 11: The correction has been made. Comment 12 : The suggested literatures can be used to reference the model equations. Response 12: The literature recommended by the reviewer has been utilized to enhance the references pertaining to adsorption models. Comment 13 : Be consistent in the use of either Pb(II) ions or Pb+2. Response 9: The use of Pb(II) or Pb+2 ions has been revised, following the reviewer's suggestions. Comment 14 : I suggest the removal of grid lines from the graphs. Response 14: Thanks for the suggestion, the authors prefer to use the grid lines because they allow a better visualization of the data in the graphs. Comment 15 : Table 1 and 3 shows the Freundlich and Langmuir isotherm parameters, not fitted equations. Response 15: The table headers have been modified in accordance with the provided suggestions. Comment 16 : Merge Table 1 and 2. Evaluate the qe parameter and present in Table 1. Response 16: Thanks for the suggestion, the authors prefer that the Tables remain separated. Comment 17 : Also merge Table 3 and 4. Response 17: Thanks for the suggestion, the authors prefer that the Tables remain separated. Comment 18 : Under pH and electric conductivity study, “….and activates substrates” Is it activates or activated?. Response 18: Correction: The accurate term is "activated". Comment 19 : There is no conclusion at the end of the manuscript, is that the journal format?. Response 19: The conclusion has been incorporated into the manuscript. Comment 20 : I recommend the following references must be added to enrich the manuscript. Response 20: The references have been downloaded and reviewed. The most pertinent ones have been incorporated into the discussion. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang We thank to the reviewer for their comments Comment 1 : The language of the manuscript must be improved by a native English editor. There are a number of grammatical errors. Response 1: The linguistic aspects of the manuscript in English have undergone a review and necessary corrections. Comment 2 : I suggest the addition of continuous line numbering to enhance review effectiveness. Response 2: The magazine format template does not include continuous numbering in the lines of the manuscript. Comment 3: The abstract must be summarized and rewritten to briefly capture the background, aim of the study, methodology, key results, and the main conclusion. Additional quantification of the results in the abstract is recommended. Response 3: The abstract has been meticulously crafted to align with the stipulated guidelines of the journal (300 words). The information has been expanded following the suggestions given. Notably, the results paragraph incorporates main quantitative data obtained in the research. Comment 4 : In the introduction, describe the hazardous effects of the Pb(II) ions heavy metals. The suggested literatures can guide the authors. Response 4: The introduction has been improved in accordance with the suggestions provided by the reviewer. Comment 5 : I suggest the addition of more treatment techniques such as photocatalysis, adsorption, advanced oxidation process, membrane filtration. Also, each of the mentioned techniques must be referenced. The recommended literature can guide the authors. Response 5: The authors do not intend to provide a comprehensive "state of the art" on lead removal. Nevertheless, we have enhanced the introduction based on the literature recommended by the reviewer. Comment 6 : 2nd paragraph: “Amorphous nanoaluminophosphates have also been proved for lead removing from…” I suggest removing be changed to removal. The entire statement must also be rephrased accordingly. Response 6: The suggested change has been made. Comment 7 : How was the OLM chemically characterized and where are the results?. Response 7: The OLM has undergone both physical and chemical characterization, with the results referenced in the cited literature. However, the authors have chosen to incorporate some of these findings into the methodology section. Comment 8 : Under the preparation of adsorbent, “The lithologic material was crushing…” Crushing or crushed?. Response 4: Correction, the word is “crushed”. Comment 9 : Why use furnace to dry at 150 ºC. Is drying done with furnace or oven?. Response 9: The drying process occurs in two steps: first, air drying for 24 hours, followed by oven drying for an additional 24 hours. These sequential drying steps ensure the complete removal of water from the substrate. Any residual occluded water in the pellet maybe a risk of explosion during the calcination process, leading to the destruction of the pellet. Comment 10 : How is oxides formation favored by calcination?. Response 10: Throughout thermal treatment, oxygen exhibits high reactivity, making surface oxidation the most likely reaction in the substrate. This process is a routine procedure for oxide formation in laboratory settings. “Brett NH. (1991). Magnesium and Alkaline-Earth Oxides. Concise Encyclopedia of Advanced Ceramic Materials. https://doi.org/10.1016/B978-0-08-034720-2.50080-0”. Comment 11 : Kindly remove this statement from the bracket. “(The non-treated...substrate). Response 11: The correction has been made. Comment 12 : The suggested literatures can be used to reference the model equations. Response 12: The literature recommended by the reviewer has been utilized to enhance the references pertaining to adsorption models. Comment 13 : Be consistent in the use of either Pb(II) ions or Pb+2. Response 9: The use of Pb(II) or Pb+2 ions has been revised, following the reviewer's suggestions. Comment 14 : I suggest the removal of grid lines from the graphs. Response 14: Thanks for the suggestion, the authors prefer to use the grid lines because they allow a better visualization of the data in the graphs. Comment 15 : Table 1 and 3 shows the Freundlich and Langmuir isotherm parameters, not fitted equations. Response 15: The table headers have been modified in accordance with the provided suggestions. Comment 16 : Merge Table 1 and 2. Evaluate the qe parameter and present in Table 1. Response 16: Thanks for the suggestion, the authors prefer that the Tables remain separated. Comment 17 : Also merge Table 3 and 4. Response 17: Thanks for the suggestion, the authors prefer that the Tables remain separated. Comment 18 : Under pH and electric conductivity study, “….and activates substrates” Is it activates or activated?. Response 18: Correction: The accurate term is "activated". Comment 19 : There is no conclusion at the end of the manuscript, is that the journal format?. Response 19: The conclusion has been incorporated into the manuscript. Comment 20 : I recommend the following references must be added to enrich the manuscript. Response 20: The references have been downloaded and reviewed. The most pertinent ones have been incorporated into the discussion. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang Competing Interests: No competing interests were disclosed. Close Report a concern Respond or Comment COMMENTS ON THIS REPORT Author Response 13 Apr 2024 JOSE PRATO MORENO , Grupo de Investigación Estudios Interdisciplinarios, Ingeniería Ambiental, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, 060103, Ecuador 13 Apr 2024 Author Response We thank to the reviewer for their comments Comment 1 : The language of the manuscript must be improved by a native English editor. There are a number of grammatical ... Continue reading We thank to the reviewer for their comments Comment 1 : The language of the manuscript must be improved by a native English editor. There are a number of grammatical errors. Response 1: The linguistic aspects of the manuscript in English have undergone a review and necessary corrections. Comment 2 : I suggest the addition of continuous line numbering to enhance review effectiveness. Response 2: The magazine format template does not include continuous numbering in the lines of the manuscript. Comment 3: The abstract must be summarized and rewritten to briefly capture the background, aim of the study, methodology, key results, and the main conclusion. Additional quantification of the results in the abstract is recommended. Response 3: The abstract has been meticulously crafted to align with the stipulated guidelines of the journal (300 words). The information has been expanded following the suggestions given. Notably, the results paragraph incorporates main quantitative data obtained in the research. Comment 4 : In the introduction, describe the hazardous effects of the Pb(II) ions heavy metals. The suggested literatures can guide the authors. Response 4: The introduction has been improved in accordance with the suggestions provided by the reviewer. Comment 5 : I suggest the addition of more treatment techniques such as photocatalysis, adsorption, advanced oxidation process, membrane filtration. Also, each of the mentioned techniques must be referenced. The recommended literature can guide the authors. Response 5: The authors do not intend to provide a comprehensive "state of the art" on lead removal. Nevertheless, we have enhanced the introduction based on the literature recommended by the reviewer. Comment 6 : 2nd paragraph: “Amorphous nanoaluminophosphates have also been proved for lead removing from…” I suggest removing be changed to removal. The entire statement must also be rephrased accordingly. Response 6: The suggested change has been made. Comment 7 : How was the OLM chemically characterized and where are the results?. Response 7: The OLM has undergone both physical and chemical characterization, with the results referenced in the cited literature. However, the authors have chosen to incorporate some of these findings into the methodology section. Comment 8 : Under the preparation of adsorbent, “The lithologic material was crushing…” Crushing or crushed?. Response 4: Correction, the word is “crushed”. Comment 9 : Why use furnace to dry at 150 ºC. Is drying done with furnace or oven?. Response 9: The drying process occurs in two steps: first, air drying for 24 hours, followed by oven drying for an additional 24 hours. These sequential drying steps ensure the complete removal of water from the substrate. Any residual occluded water in the pellet maybe a risk of explosion during the calcination process, leading to the destruction of the pellet. Comment 10 : How is oxides formation favored by calcination?. Response 10: Throughout thermal treatment, oxygen exhibits high reactivity, making surface oxidation the most likely reaction in the substrate. This process is a routine procedure for oxide formation in laboratory settings. “Brett NH. (1991). Magnesium and Alkaline-Earth Oxides. Concise Encyclopedia of Advanced Ceramic Materials. https://doi.org/10.1016/B978-0-08-034720-2.50080-0”. Comment 11 : Kindly remove this statement from the bracket. “(The non-treated...substrate). Response 11: The correction has been made. Comment 12 : The suggested literatures can be used to reference the model equations. Response 12: The literature recommended by the reviewer has been utilized to enhance the references pertaining to adsorption models. Comment 13 : Be consistent in the use of either Pb(II) ions or Pb+2. Response 9: The use of Pb(II) or Pb+2 ions has been revised, following the reviewer's suggestions. Comment 14 : I suggest the removal of grid lines from the graphs. Response 14: Thanks for the suggestion, the authors prefer to use the grid lines because they allow a better visualization of the data in the graphs. Comment 15 : Table 1 and 3 shows the Freundlich and Langmuir isotherm parameters, not fitted equations. Response 15: The table headers have been modified in accordance with the provided suggestions. Comment 16 : Merge Table 1 and 2. Evaluate the qe parameter and present in Table 1. Response 16: Thanks for the suggestion, the authors prefer that the Tables remain separated. Comment 17 : Also merge Table 3 and 4. Response 17: Thanks for the suggestion, the authors prefer that the Tables remain separated. Comment 18 : Under pH and electric conductivity study, “….and activates substrates” Is it activates or activated?. Response 18: Correction: The accurate term is "activated". Comment 19 : There is no conclusion at the end of the manuscript, is that the journal format?. Response 19: The conclusion has been incorporated into the manuscript. Comment 20 : I recommend the following references must be added to enrich the manuscript. Response 20: The references have been downloaded and reviewed. The most pertinent ones have been incorporated into the discussion. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang We thank to the reviewer for their comments Comment 1 : The language of the manuscript must be improved by a native English editor. There are a number of grammatical errors. Response 1: The linguistic aspects of the manuscript in English have undergone a review and necessary corrections. Comment 2 : I suggest the addition of continuous line numbering to enhance review effectiveness. Response 2: The magazine format template does not include continuous numbering in the lines of the manuscript. Comment 3: The abstract must be summarized and rewritten to briefly capture the background, aim of the study, methodology, key results, and the main conclusion. Additional quantification of the results in the abstract is recommended. Response 3: The abstract has been meticulously crafted to align with the stipulated guidelines of the journal (300 words). The information has been expanded following the suggestions given. Notably, the results paragraph incorporates main quantitative data obtained in the research. Comment 4 : In the introduction, describe the hazardous effects of the Pb(II) ions heavy metals. The suggested literatures can guide the authors. Response 4: The introduction has been improved in accordance with the suggestions provided by the reviewer. Comment 5 : I suggest the addition of more treatment techniques such as photocatalysis, adsorption, advanced oxidation process, membrane filtration. Also, each of the mentioned techniques must be referenced. The recommended literature can guide the authors. Response 5: The authors do not intend to provide a comprehensive "state of the art" on lead removal. Nevertheless, we have enhanced the introduction based on the literature recommended by the reviewer. Comment 6 : 2nd paragraph: “Amorphous nanoaluminophosphates have also been proved for lead removing from…” I suggest removing be changed to removal. The entire statement must also be rephrased accordingly. Response 6: The suggested change has been made. Comment 7 : How was the OLM chemically characterized and where are the results?. Response 7: The OLM has undergone both physical and chemical characterization, with the results referenced in the cited literature. However, the authors have chosen to incorporate some of these findings into the methodology section. Comment 8 : Under the preparation of adsorbent, “The lithologic material was crushing…” Crushing or crushed?. Response 4: Correction, the word is “crushed”. Comment 9 : Why use furnace to dry at 150 ºC. Is drying done with furnace or oven?. Response 9: The drying process occurs in two steps: first, air drying for 24 hours, followed by oven drying for an additional 24 hours. These sequential drying steps ensure the complete removal of water from the substrate. Any residual occluded water in the pellet maybe a risk of explosion during the calcination process, leading to the destruction of the pellet. Comment 10 : How is oxides formation favored by calcination?. Response 10: Throughout thermal treatment, oxygen exhibits high reactivity, making surface oxidation the most likely reaction in the substrate. This process is a routine procedure for oxide formation in laboratory settings. “Brett NH. (1991). Magnesium and Alkaline-Earth Oxides. Concise Encyclopedia of Advanced Ceramic Materials. https://doi.org/10.1016/B978-0-08-034720-2.50080-0”. Comment 11 : Kindly remove this statement from the bracket. “(The non-treated...substrate). Response 11: The correction has been made. Comment 12 : The suggested literatures can be used to reference the model equations. Response 12: The literature recommended by the reviewer has been utilized to enhance the references pertaining to adsorption models. Comment 13 : Be consistent in the use of either Pb(II) ions or Pb+2. Response 9: The use of Pb(II) or Pb+2 ions has been revised, following the reviewer's suggestions. Comment 14 : I suggest the removal of grid lines from the graphs. Response 14: Thanks for the suggestion, the authors prefer to use the grid lines because they allow a better visualization of the data in the graphs. Comment 15 : Table 1 and 3 shows the Freundlich and Langmuir isotherm parameters, not fitted equations. Response 15: The table headers have been modified in accordance with the provided suggestions. Comment 16 : Merge Table 1 and 2. Evaluate the qe parameter and present in Table 1. Response 16: Thanks for the suggestion, the authors prefer that the Tables remain separated. Comment 17 : Also merge Table 3 and 4. Response 17: Thanks for the suggestion, the authors prefer that the Tables remain separated. Comment 18 : Under pH and electric conductivity study, “….and activates substrates” Is it activates or activated?. Response 18: Correction: The accurate term is "activated". Comment 19 : There is no conclusion at the end of the manuscript, is that the journal format?. Response 19: The conclusion has been incorporated into the manuscript. Comment 20 : I recommend the following references must be added to enrich the manuscript. Response 20: The references have been downloaded and reviewed. The most pertinent ones have been incorporated into the discussion. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang Competing Interests: No competing interests were disclosed. Close Report a concern COMMENT ON THIS REPORT Views 0 Cite How to cite this report: Wang W. Reviewer Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.145832.r196304 ) The direct URL for this report is: https://f1000research.com/articles/12-747/v1#referee-response-196304 NOTE: it is important to ensure the information in square brackets after the title is included in this citation. Close Copy Citation Details Reviewer Report 03 Nov 2023 Wei Wang , Zhengzhou University, Zhengzhou, Henan, China Approved with Reservations VIEWS 0 https://doi.org/10.5256/f1000research.145832.r196304 This paper presents the adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface. Authors should consider the following observations: 1. Include some novel findings as in numerical results in abstract. ... Continue reading READ ALL This paper presents the adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface. Authors should consider the following observations: 1. Include some novel findings as in numerical results in abstract. 2. The quality of the data analysis is not solid enough. 3. The adsorption mechanism was important and needed to discuss in-depth with characterization support. 4. Compare the present research with the previous literatures. Is the work clearly and accurately presented and does it cite the current literature? Yes Is the study design appropriate and is the work technically sound? Yes Are sufficient details of methods and analysis provided to allow replication by others? Yes If applicable, is the statistical analysis and its interpretation appropriate? Partly Are all the source data underlying the results available to ensure full reproducibility? Partly Are the conclusions drawn adequately supported by the results? Yes Competing Interests: No competing interests were disclosed. Reviewer Expertise: Mineral material; adsorption; catalyst I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. Close READ LESS CITE CITE HOW TO CITE THIS REPORT Wang W. Reviewer Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.145832.r196304 ) The direct URL for this report is: https://f1000research.com/articles/12-747/v1#referee-response-196304 NOTE: it is important to ensure the information in square brackets after the title is included in all citations of this article. COPY CITATION DETAILS Report a concern Author Response 13 Apr 2024 JOSE PRATO MORENO , Grupo de Investigación Estudios Interdisciplinarios, Ingeniería Ambiental, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, 060103, Ecuador 13 Apr 2024 Author Response We thank to the reviewer for their comments Comment 1 : Include some novel findings as in numerical results in abstract. Response 1: The abstract has undergone revision, corrected and ... Continue reading We thank to the reviewer for their comments Comment 1 : Include some novel findings as in numerical results in abstract. Response 1: The abstract has undergone revision, corrected and structured in accordance with the journal's guidelines. The reported values in the results paragraph, correspond to the main quantitative data obtained in the research. Comment 2 : The quality of the data analysis is not solid enough. Response 2: The manuscript underwent a comprehensive review, leading to enhancements in the presentation of results through the implementation of valuable recommendations provided by the reviewers. Comment 3: The adsorption mechanism was important and needed to discuss in-depth with characterization support. Response 3: The OLM has undergone both physical and chemical characterization, with the results referenced in the published and cited literature. However, the authors have chosen to incorporate some of these findings into the methodology section. Furthermore, in response to the reviewer's valuable suggestions, the enhancement of adsorption results analysis has been achieved. Notably, particular attention has been given to incorporating material characterization in the analysis. Comment 4 : Compare the present research with the previous literatures. Response 4: The results have been compared with other reported investigations and have been added to the paper. Thank you again for your review. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang We thank to the reviewer for their comments Comment 1 : Include some novel findings as in numerical results in abstract. Response 1: The abstract has undergone revision, corrected and structured in accordance with the journal's guidelines. The reported values in the results paragraph, correspond to the main quantitative data obtained in the research. Comment 2 : The quality of the data analysis is not solid enough. Response 2: The manuscript underwent a comprehensive review, leading to enhancements in the presentation of results through the implementation of valuable recommendations provided by the reviewers. Comment 3: The adsorption mechanism was important and needed to discuss in-depth with characterization support. Response 3: The OLM has undergone both physical and chemical characterization, with the results referenced in the published and cited literature. However, the authors have chosen to incorporate some of these findings into the methodology section. Furthermore, in response to the reviewer's valuable suggestions, the enhancement of adsorption results analysis has been achieved. Notably, particular attention has been given to incorporating material characterization in the analysis. Comment 4 : Compare the present research with the previous literatures. Response 4: The results have been compared with other reported investigations and have been added to the paper. Thank you again for your review. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang Competing Interests: No competing interests were disclosed. Close Report a concern Respond or Comment COMMENTS ON THIS REPORT Author Response 13 Apr 2024 JOSE PRATO MORENO , Grupo de Investigación Estudios Interdisciplinarios, Ingeniería Ambiental, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, 060103, Ecuador 13 Apr 2024 Author Response We thank to the reviewer for their comments Comment 1 : Include some novel findings as in numerical results in abstract. Response 1: The abstract has undergone revision, corrected and ... Continue reading We thank to the reviewer for their comments Comment 1 : Include some novel findings as in numerical results in abstract. Response 1: The abstract has undergone revision, corrected and structured in accordance with the journal's guidelines. The reported values in the results paragraph, correspond to the main quantitative data obtained in the research. Comment 2 : The quality of the data analysis is not solid enough. Response 2: The manuscript underwent a comprehensive review, leading to enhancements in the presentation of results through the implementation of valuable recommendations provided by the reviewers. Comment 3: The adsorption mechanism was important and needed to discuss in-depth with characterization support. Response 3: The OLM has undergone both physical and chemical characterization, with the results referenced in the published and cited literature. However, the authors have chosen to incorporate some of these findings into the methodology section. Furthermore, in response to the reviewer's valuable suggestions, the enhancement of adsorption results analysis has been achieved. Notably, particular attention has been given to incorporating material characterization in the analysis. Comment 4 : Compare the present research with the previous literatures. Response 4: The results have been compared with other reported investigations and have been added to the paper. Thank you again for your review. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang We thank to the reviewer for their comments Comment 1 : Include some novel findings as in numerical results in abstract. Response 1: The abstract has undergone revision, corrected and structured in accordance with the journal's guidelines. The reported values in the results paragraph, correspond to the main quantitative data obtained in the research. Comment 2 : The quality of the data analysis is not solid enough. Response 2: The manuscript underwent a comprehensive review, leading to enhancements in the presentation of results through the implementation of valuable recommendations provided by the reviewers. Comment 3: The adsorption mechanism was important and needed to discuss in-depth with characterization support. Response 3: The OLM has undergone both physical and chemical characterization, with the results referenced in the published and cited literature. However, the authors have chosen to incorporate some of these findings into the methodology section. Furthermore, in response to the reviewer's valuable suggestions, the enhancement of adsorption results analysis has been achieved. Notably, particular attention has been given to incorporating material characterization in the analysis. Comment 4 : Compare the present research with the previous literatures. Response 4: The results have been compared with other reported investigations and have been added to the paper. Thank you again for your review. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang Competing Interests: No competing interests were disclosed. Close Report a concern COMMENT ON THIS REPORT Views 0 Cite How to cite this report: Dinca N. Reviewer Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.145832.r183567 ) The direct URL for this report is: https://f1000research.com/articles/12-747/v1#referee-response-183567 NOTE: it is important to ensure the information in square brackets after the title is included in this citation. Close Copy Citation Details Reviewer Report 05 Sep 2023 Nicolae Dinca , Department of Technical and Natural Sciences, Faculty of Food Engineering, Tourism and Environmental Protection, “Aurel Vlaicu” University, Arad, Romania Approved with Reservations VIEWS 0 https://doi.org/10.5256/f1000research.145832.r183567 The work is topical because it scientifically substantiates the possibility of valorizing some indigenous raw materials in the process of purifying residual waters containing Pb +2 resulting from human activity. The experimental design described on page 4 above, ... Continue reading READ ALL The work is topical because it scientifically substantiates the possibility of valorizing some indigenous raw materials in the process of purifying residual waters containing Pb +2 resulting from human activity. The experimental design described on page 4 above, considers the sample volume as a variable factor and the constant Pb +2 concentration (0.001 M), while the results suggest that the sample volume is constant and the concentration is variable. I believe that the confusing text from Methods Adsorption studies (page 4, lines 6-8) should be corrected. Ci is not defined in the text (page 4, line 8). If the values of column n in Table 1 are well calculated, then they do not correspond to equations (1) and (2) in the form of the work dated 26 Jun 2023, 12:74. I believe that these equations should be corrected by replacing n with 1/n . Fig.1 indicates that at low and medium initial ( Ci ) Pb +2 concentrations, the adsorption speeds (at 24h) are higher for the activated material. On page 6, line 5, k 1 and k 2 appear which are not defined in the text and do not appear in eqs. (3-4). K 1 (page 6 line 7) is identical to k 1 from line 5? Technological perspectives that could complement the conclusions (optional): The isotherms in Fig. 1 show that an optimal option in practical applications would be the use of two ion exchange columns linked in series: the first one containing non-activated substrate (cheaper) and the second one containing activated substrate. pH and conductivity measurements can be accessible technical options for monitoring the purification process. Is the work clearly and accurately presented and does it cite the current literature? Yes Is the study design appropriate and is the work technically sound? Yes Are sufficient details of methods and analysis provided to allow replication by others? Partly If applicable, is the statistical analysis and its interpretation appropriate? Yes Are all the source data underlying the results available to ensure full reproducibility? Yes Are the conclusions drawn adequately supported by the results? Yes Competing Interests: No competing interests were disclosed. Reviewer Expertise: chemistry I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. Close READ LESS CITE CITE HOW TO CITE THIS REPORT Dinca N. Reviewer Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.145832.r183567 ) The direct URL for this report is: https://f1000research.com/articles/12-747/v1#referee-response-183567 NOTE: it is important to ensure the information in square brackets after the title is included in all citations of this article. COPY CITATION DETAILS Report a concern Author Response 03 Apr 2024 JOSE PRATO MORENO , Grupo de Investigación Estudios Interdisciplinarios, Ingeniería Ambiental, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, 060103, Ecuador 03 Apr 2024 Author Response We thank the reviewer for the importance has given to our research, the time spent correcting the manuscript, their knowledge, experience, and willingness to improve the article. Comment 1 : ... Continue reading We thank the reviewer for the importance has given to our research, the time spent correcting the manuscript, their knowledge, experience, and willingness to improve the article. Comment 1 : The experimental design described on page 4 above, considers the sample volume as a variable factor and the constant Pb +2 concentration (0.001 M), while the results suggest that the sample volume is constant and the concentration is variable. I believe that the confusing text from Methods Adsorption studies (page 4, lines 6-8) should be corrected. Response 1: Seven samples of 2 g of substrate, activated and non-activates, were treated with increasing aliquots of 5, 10, 15, 20, 25, 30 and 40 mL of a 1 mM Pb +2 solution. Samples are let to stand, in isothermal conditions, during 24 hours, and periodically shacked. So, the number of millimoles in each one of the samples is known. Comment 2 : Ci is not defined in the text (page 4, line 8). Response 2: It is corrected, defining Ci in the text, section on adsorption studies. Comment 3: If the values of column n in Table 1 are well calculated, then they do not correspond to equations (1) and (2) in the form of the work dated 26 Jun 2023, 12:74. I believe that these equations should be corrected by replacing n with 1/n. Response 3: “n” values are god, what is wrong is equation 2, where exponential term is not n but 1/n. therefore, equations 1 and 2 become: Comment 4 : Fig.1 indicates that at low and medium initial (Ci) Pb +2 concentrations, the adsorption speeds (at 24h) are higher for the activated material. Response 4: Taking into account the observation made, the wording has been modified regarding Fig 1, in the results and discussion sections: Results: Isotherm graph Figure 1 a shows the adsorption isotherms of Pb +2 ions on the activated and non-activated substrates. Although the isotherm profile shows but doesn't confirm information about of the interaction between Pb +2 ions and substrate surface, L -type isotherm is associated with great affinity between sorbent and sorbate. At low equilibrium concentrations, the amount adsorbed increases rapidly, while at high concentrations it decreases, getting to a saturation zone. At low concentration non-activated substrate shows less affinity for Pb +2 ions compared to activated substrate, however, at higher concentration the adsorption isotherm become linear increasing Pb +2 adsorption. It might suggest collateral mechanism for the lead ions adsorption. Discussion: Figure 1 a , shows the isotherm for non-activated substrate. At low concentrations, a similar kind of adsorption but much less intense, showing less affinity for Pb +2 adsorption. However, at higher concentrations, adsorption increases according to a linear model. Most likely acetate ions, being strong base, deprotonates oxides in favor of Pb +2 adsorption, according to the reaction (7) FeOH + CH 3 COO¯ → FeO¯+ CH 3 COOH Therefore, adsorption of Pb +2 ions take place after oxide deprotonation via acetate ion, according to a multilayer physic adsorption model. After all, acetate ions, being a strong base, might compete in the oxide deprotonation to form molecular acetic acid. Comment 5 : On page 6, line 5, k1 and k2 appear which are not defined in the text and do not appear in eqs. (3-4). K1 (page 6 line 7) is identical to k1 from line 5?. Response 5: k 1 and k 2 have been defined in the text and equations 3 and 4 have been adjusted, as detailed below: In equations 3 and 4, q e is the amount adsorbed per adsorbent weight unit, C eq is the equilibrium concentration of adsorbate in solution after adsorption, k 1 is the Langmuir constant related to the affinity between adsorbate and adsorbent, and k 2 is the adsorption capacity, which represents the maximum amount of adsorbate in a monolayer. The parameters of the isotherm are obtained by plotting C eq /q e versus C eq , resulting in a straight line with slope equal to 1/(k 1 * k 2 ) and the intersection equal to 1/k 2 . Thank you again for your review. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang We thank the reviewer for the importance has given to our research, the time spent correcting the manuscript, their knowledge, experience, and willingness to improve the article. Comment 1 : The experimental design described on page 4 above, considers the sample volume as a variable factor and the constant Pb +2 concentration (0.001 M), while the results suggest that the sample volume is constant and the concentration is variable. I believe that the confusing text from Methods Adsorption studies (page 4, lines 6-8) should be corrected. Response 1: Seven samples of 2 g of substrate, activated and non-activates, were treated with increasing aliquots of 5, 10, 15, 20, 25, 30 and 40 mL of a 1 mM Pb +2 solution. Samples are let to stand, in isothermal conditions, during 24 hours, and periodically shacked. So, the number of millimoles in each one of the samples is known. Comment 2 : Ci is not defined in the text (page 4, line 8). Response 2: It is corrected, defining Ci in the text, section on adsorption studies. Comment 3: If the values of column n in Table 1 are well calculated, then they do not correspond to equations (1) and (2) in the form of the work dated 26 Jun 2023, 12:74. I believe that these equations should be corrected by replacing n with 1/n. Response 3: “n” values are god, what is wrong is equation 2, where exponential term is not n but 1/n. therefore, equations 1 and 2 become: Comment 4 : Fig.1 indicates that at low and medium initial (Ci) Pb +2 concentrations, the adsorption speeds (at 24h) are higher for the activated material. Response 4: Taking into account the observation made, the wording has been modified regarding Fig 1, in the results and discussion sections: Results: Isotherm graph Figure 1 a shows the adsorption isotherms of Pb +2 ions on the activated and non-activated substrates. Although the isotherm profile shows but doesn't confirm information about of the interaction between Pb +2 ions and substrate surface, L -type isotherm is associated with great affinity between sorbent and sorbate. At low equilibrium concentrations, the amount adsorbed increases rapidly, while at high concentrations it decreases, getting to a saturation zone. At low concentration non-activated substrate shows less affinity for Pb +2 ions compared to activated substrate, however, at higher concentration the adsorption isotherm become linear increasing Pb +2 adsorption. It might suggest collateral mechanism for the lead ions adsorption. Discussion: Figure 1 a , shows the isotherm for non-activated substrate. At low concentrations, a similar kind of adsorption but much less intense, showing less affinity for Pb +2 adsorption. However, at higher concentrations, adsorption increases according to a linear model. Most likely acetate ions, being strong base, deprotonates oxides in favor of Pb +2 adsorption, according to the reaction (7) FeOH + CH 3 COO¯ → FeO¯+ CH 3 COOH Therefore, adsorption of Pb +2 ions take place after oxide deprotonation via acetate ion, according to a multilayer physic adsorption model. After all, acetate ions, being a strong base, might compete in the oxide deprotonation to form molecular acetic acid. Comment 5 : On page 6, line 5, k1 and k2 appear which are not defined in the text and do not appear in eqs. (3-4). K1 (page 6 line 7) is identical to k1 from line 5?. Response 5: k 1 and k 2 have been defined in the text and equations 3 and 4 have been adjusted, as detailed below: In equations 3 and 4, q e is the amount adsorbed per adsorbent weight unit, C eq is the equilibrium concentration of adsorbate in solution after adsorption, k 1 is the Langmuir constant related to the affinity between adsorbate and adsorbent, and k 2 is the adsorption capacity, which represents the maximum amount of adsorbate in a monolayer. The parameters of the isotherm are obtained by plotting C eq /q e versus C eq , resulting in a straight line with slope equal to 1/(k 1 * k 2 ) and the intersection equal to 1/k 2 . Thank you again for your review. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang Competing Interests: No competing interests were disclosed. Close Report a concern Respond or Comment COMMENTS ON THIS REPORT Author Response 03 Apr 2024 JOSE PRATO MORENO , Grupo de Investigación Estudios Interdisciplinarios, Ingeniería Ambiental, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, 060103, Ecuador 03 Apr 2024 Author Response We thank the reviewer for the importance has given to our research, the time spent correcting the manuscript, their knowledge, experience, and willingness to improve the article. Comment 1 : ... Continue reading We thank the reviewer for the importance has given to our research, the time spent correcting the manuscript, their knowledge, experience, and willingness to improve the article. Comment 1 : The experimental design described on page 4 above, considers the sample volume as a variable factor and the constant Pb +2 concentration (0.001 M), while the results suggest that the sample volume is constant and the concentration is variable. I believe that the confusing text from Methods Adsorption studies (page 4, lines 6-8) should be corrected. Response 1: Seven samples of 2 g of substrate, activated and non-activates, were treated with increasing aliquots of 5, 10, 15, 20, 25, 30 and 40 mL of a 1 mM Pb +2 solution. Samples are let to stand, in isothermal conditions, during 24 hours, and periodically shacked. So, the number of millimoles in each one of the samples is known. Comment 2 : Ci is not defined in the text (page 4, line 8). Response 2: It is corrected, defining Ci in the text, section on adsorption studies. Comment 3: If the values of column n in Table 1 are well calculated, then they do not correspond to equations (1) and (2) in the form of the work dated 26 Jun 2023, 12:74. I believe that these equations should be corrected by replacing n with 1/n. Response 3: “n” values are god, what is wrong is equation 2, where exponential term is not n but 1/n. therefore, equations 1 and 2 become: Comment 4 : Fig.1 indicates that at low and medium initial (Ci) Pb +2 concentrations, the adsorption speeds (at 24h) are higher for the activated material. Response 4: Taking into account the observation made, the wording has been modified regarding Fig 1, in the results and discussion sections: Results: Isotherm graph Figure 1 a shows the adsorption isotherms of Pb +2 ions on the activated and non-activated substrates. Although the isotherm profile shows but doesn't confirm information about of the interaction between Pb +2 ions and substrate surface, L -type isotherm is associated with great affinity between sorbent and sorbate. At low equilibrium concentrations, the amount adsorbed increases rapidly, while at high concentrations it decreases, getting to a saturation zone. At low concentration non-activated substrate shows less affinity for Pb +2 ions compared to activated substrate, however, at higher concentration the adsorption isotherm become linear increasing Pb +2 adsorption. It might suggest collateral mechanism for the lead ions adsorption. Discussion: Figure 1 a , shows the isotherm for non-activated substrate. At low concentrations, a similar kind of adsorption but much less intense, showing less affinity for Pb +2 adsorption. However, at higher concentrations, adsorption increases according to a linear model. Most likely acetate ions, being strong base, deprotonates oxides in favor of Pb +2 adsorption, according to the reaction (7) FeOH + CH 3 COO¯ → FeO¯+ CH 3 COOH Therefore, adsorption of Pb +2 ions take place after oxide deprotonation via acetate ion, according to a multilayer physic adsorption model. After all, acetate ions, being a strong base, might compete in the oxide deprotonation to form molecular acetic acid. Comment 5 : On page 6, line 5, k1 and k2 appear which are not defined in the text and do not appear in eqs. (3-4). K1 (page 6 line 7) is identical to k1 from line 5?. Response 5: k 1 and k 2 have been defined in the text and equations 3 and 4 have been adjusted, as detailed below: In equations 3 and 4, q e is the amount adsorbed per adsorbent weight unit, C eq is the equilibrium concentration of adsorbate in solution after adsorption, k 1 is the Langmuir constant related to the affinity between adsorbate and adsorbent, and k 2 is the adsorption capacity, which represents the maximum amount of adsorbate in a monolayer. The parameters of the isotherm are obtained by plotting C eq /q e versus C eq , resulting in a straight line with slope equal to 1/(k 1 * k 2 ) and the intersection equal to 1/k 2 . Thank you again for your review. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang We thank the reviewer for the importance has given to our research, the time spent correcting the manuscript, their knowledge, experience, and willingness to improve the article. Comment 1 : The experimental design described on page 4 above, considers the sample volume as a variable factor and the constant Pb +2 concentration (0.001 M), while the results suggest that the sample volume is constant and the concentration is variable. I believe that the confusing text from Methods Adsorption studies (page 4, lines 6-8) should be corrected. Response 1: Seven samples of 2 g of substrate, activated and non-activates, were treated with increasing aliquots of 5, 10, 15, 20, 25, 30 and 40 mL of a 1 mM Pb +2 solution. Samples are let to stand, in isothermal conditions, during 24 hours, and periodically shacked. So, the number of millimoles in each one of the samples is known. Comment 2 : Ci is not defined in the text (page 4, line 8). Response 2: It is corrected, defining Ci in the text, section on adsorption studies. Comment 3: If the values of column n in Table 1 are well calculated, then they do not correspond to equations (1) and (2) in the form of the work dated 26 Jun 2023, 12:74. I believe that these equations should be corrected by replacing n with 1/n. Response 3: “n” values are god, what is wrong is equation 2, where exponential term is not n but 1/n. therefore, equations 1 and 2 become: Comment 4 : Fig.1 indicates that at low and medium initial (Ci) Pb +2 concentrations, the adsorption speeds (at 24h) are higher for the activated material. Response 4: Taking into account the observation made, the wording has been modified regarding Fig 1, in the results and discussion sections: Results: Isotherm graph Figure 1 a shows the adsorption isotherms of Pb +2 ions on the activated and non-activated substrates. Although the isotherm profile shows but doesn't confirm information about of the interaction between Pb +2 ions and substrate surface, L -type isotherm is associated with great affinity between sorbent and sorbate. At low equilibrium concentrations, the amount adsorbed increases rapidly, while at high concentrations it decreases, getting to a saturation zone. At low concentration non-activated substrate shows less affinity for Pb +2 ions compared to activated substrate, however, at higher concentration the adsorption isotherm become linear increasing Pb +2 adsorption. It might suggest collateral mechanism for the lead ions adsorption. Discussion: Figure 1 a , shows the isotherm for non-activated substrate. At low concentrations, a similar kind of adsorption but much less intense, showing less affinity for Pb +2 adsorption. However, at higher concentrations, adsorption increases according to a linear model. Most likely acetate ions, being strong base, deprotonates oxides in favor of Pb +2 adsorption, according to the reaction (7) FeOH + CH 3 COO¯ → FeO¯+ CH 3 COOH Therefore, adsorption of Pb +2 ions take place after oxide deprotonation via acetate ion, according to a multilayer physic adsorption model. After all, acetate ions, being a strong base, might compete in the oxide deprotonation to form molecular acetic acid. Comment 5 : On page 6, line 5, k1 and k2 appear which are not defined in the text and do not appear in eqs. (3-4). K1 (page 6 line 7) is identical to k1 from line 5?. Response 5: k 1 and k 2 have been defined in the text and equations 3 and 4 have been adjusted, as detailed below: In equations 3 and 4, q e is the amount adsorbed per adsorbent weight unit, C eq is the equilibrium concentration of adsorbate in solution after adsorption, k 1 is the Langmuir constant related to the affinity between adsorbate and adsorbent, and k 2 is the adsorption capacity, which represents the maximum amount of adsorbate in a monolayer. The parameters of the isotherm are obtained by plotting C eq /q e versus C eq , resulting in a straight line with slope equal to 1/(k 1 * k 2 ) and the intersection equal to 1/k 2 . Thank you again for your review. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang Competing Interests: No competing interests were disclosed. Close Report a concern COMMENT ON THIS REPORT Comments on this article Comments (0) Version 2 VERSION 2 PUBLISHED 26 Jun 2023 ADD YOUR COMMENT Comment keyboard_arrow_left keyboard_arrow_right Open Peer Review Reviewer Status info_outline Alongside their report, reviewers assign a status to the article: Approved The paper is scientifically sound in its current form and only minor, if any, improvements are suggested Approved with reservations A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit. Not approved Fundamental flaws in the paper seriously undermine the findings and conclusions Reviewer Reports Invited Reviewers 1 2 3 Version 2 (revision) 28 Mar 24 read Version 1 26 Jun 23 read read read Nicolae Dinca , “Aurel Vlaicu” University, Arad, Romania Wei Wang , Zhengzhou University, Zhengzhou, China Titus Chinedu Egbosiuba , Texas A&M University, College Station, USA Comments on this article All Comments (0) Add a comment Sign up for content alerts Sign Up You are now signed up to receive this alert Browse by related subjects keyboard_arrow_left Back to all reports Reviewer Report 0 Views copyright © 2024 Dinca N. This is an open access peer review report distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 02 Apr 2024 | for Version 2 Nicolae Dinca , Department of Technical and Natural Sciences, Faculty of Food Engineering, Tourism and Environmental Protection, “Aurel Vlaicu” University, Arad, Romania 0 Views copyright © 2024 Dinca N. This is an open access peer review report distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. format_quote Cite this report speaker_notes Responses (0) Approved info_outline Alongside their report, reviewers assign a status to the article: Approved The paper is scientifically sound in its current form and only minor, if any, improvements are suggested Approved with reservations A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit. Not approved Fundamental flaws in the paper seriously undermine the findings and conclusions Thanks, the revised form includes all my requests for improving the work. I have no other comments to make. Competing Interests No competing interests were disclosed. Reviewer Expertise chemistry I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard. reply Respond to this report Responses (0) Dinca N. Peer Review Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.163125.r260344) NOTE: it is important to ensure the information in square brackets after the title is included in this citation. The direct URL for this report is: https://f1000research.com/articles/12-747/v2#referee-response-260344 keyboard_arrow_left Back to all reports Reviewer Report 0 Views copyright © 2023 Chinedu Egbosiuba T. This is an open access peer review report distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 03 Nov 2023 | for Version 1 Titus Chinedu Egbosiuba , Texas A&M University, College Station, Texas, USA 0 Views copyright © 2023 Chinedu Egbosiuba T. This is an open access peer review report distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. format_quote Cite this report speaker_notes Responses (1) Approved With Reservations info_outline Alongside their report, reviewers assign a status to the article: Approved The paper is scientifically sound in its current form and only minor, if any, improvements are suggested Approved with reservations A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit. Not approved Fundamental flaws in the paper seriously undermine the findings and conclusions F1000 Research Review The study reported “Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface ”. The authors prepared oxidic calcined and chemically modified substrates for the removal of Pb (II) ions from wastewater. I recommend the reconsideration of the manuscript for approval after the following comments are addressed: Comments The language of the manuscript must be improved by a native English editor. There are a number of grammatical errors. I suggest the addition of continuous line numbering to enhance review effectiveness. The abstract must be summarized and rewritten to briefly capture the background, aim of the study, methodology, key results, and the main conclusion. Additional quantification of the results in the abstract is recommended. In the introduction, describe the hazardous effects of the Pb(II) ions heavy metals. The suggested literatures can guide the authors. I suggest the addition of more treatment techniques such as photocatalysis, adsorption, advanced oxidation process, membrane filtration. Also, each of the mentioned techniques must be referenced. The recommended literature can guide the authors. 2 nd paragraph: “Amorphous nanoaluminophosphates have also been proved for lead removing from…” I suggest removing be changed to removal. The entire statement must also be rephrased accordingly. How was the OLM chemically characterized and where are the results? Under the preparation of adsorbent, “The lithologic material was crushing…” Crushing or crushed? Why use furnace to dry at 150 o C. Is drying done with furnace or oven? How is oxides formation favored by calcination? Reference please. Kindly remove this statement from the bracket. “(The non-treated...substrate). The suggested literatures can be used to reference the model equations. Be consistent in the use of either Pb(II) ions or Pb +2 . I suggest the removal of grid lines from the graphs. Table 1 and 3 shows the Freundlich and Langmuir isotherm parameters, not fitted equations. Merge Table 1 and 2. Evaluate the qe parameter and present in Table 1. Also merge Table 3 and 4. Under pH and electric conductivity study, “….and activates substrates” Is it activates or activated? There is no conclusion at the end of the manuscript, is that the journal format? I recommend the following references must be added to enrich the manuscript 1 - 18 . Is the work clearly and accurately presented and does it cite the current literature? Yes Is the study design appropriate and is the work technically sound? Yes Are sufficient details of methods and analysis provided to allow replication by others? Yes If applicable, is the statistical analysis and its interpretation appropriate? Yes Are all the source data underlying the results available to ensure full reproducibility? Yes Are the conclusions drawn adequately supported by the results? No References 1. Alex Mbachu C, Kamoru Babayemi A, Chinedu Egbosiuba T, Ifeanyichukwu Ike J, et al.: Green synthesis of iron oxide nanoparticles by Taguchi design of experiment method for effective adsorption of methylene blue and methyl orange from textile wastewater. Results in Engineering . 2023; 19 . Publisher Full Text 2. Kilinc B, Akagunduz D, Ozdemir M, Kul A, et al.: Hydrogen production using cocaine metabolite in microbial electrolysis cells. 3 Biotech . 2023; 13 (11): 382 PubMed Abstract | Publisher Full Text 3. Sagadevan S, Fatimah I, Egbosiuba T, Alshahateet S, et al.: Photocatalytic Efficiency of Titanium Dioxide for Dyes and Heavy Metals Removal from Wastewater. Bulletin of Chemical Reaction Engineering & Catalysis . 2022; 17 (2): 430-450 Publisher Full Text 4. Chukwu Onu D, Kamoru Babayemi A, Chinedu Egbosiuba T, Onyinye Okafor B, et al.: Isotherm, kinetics, thermodynamics, recyclability and mechanism of ultrasonic assisted adsorption of methylene blue and lead (II) ions using green synthesized nickel oxide nanoparticles. Environmental Nanotechnology, Monitoring & Management . 2023; 20 . Publisher Full Text 5. Abdulkareem A, Hamzat W, Tijani J, Egbosiuba T, et al.: Isotherm, kinetics, thermodynamics and mechanism of metal ions adsorption from electroplating wastewater using treated and functionalized carbon nanotubes. Journal of Environmental Chemical Engineering . 2023; 11 (1). Publisher Full Text 6. Egbosiuba T, Abdulkareem A, Kovo A, Afolabi E, et al.: Ultrasonic enhanced adsorption of methylene blue onto the optimized surface area of activated carbon: Adsorption isotherm, kinetics and thermodynamics. Chemical Engineering Research and Design . 2020; 153 : 315-336 Publisher Full Text 7. Aliyu S, Ambali A, Oladejo T, Mustapha S, et al.: Development of Ag-doped on multi-walled carbon nanotubes for the treatment of fish pond effluent. Regional Studies in Marine Science . 2023; 58 . Publisher Full Text 8. Egbosiuba T, Abdulkareem A: Highly efficient as-synthesized and oxidized multi-walled carbon nanotubes for copper(II) and zinc(II) ion adsorption in a batch and fixed-bed process. Journal of Materials Research and Technology . 2021; 15 : 2848-2872 Publisher Full Text 9. Uko C, Tijani J, Abdulkareem S, Mustapha S, et al.: Adsorptive properties of MgO/WO3 nanoadsorbent for selected heavy metals removal from indigenous dyeing wastewater. Process Safety and Environmental Protection . 2022; 162 : 775-794 Publisher Full Text 10. Egbosiuba TC, Abdulkareem AS, Tijani JO, Ani JI, et al.: Taguchi optimization design of diameter-controlled synthesis of multi walled carbon nanotubes for the adsorption of Pb(II) and Ni(II) from chemical industry wastewater. Chemosphere . 2021; 266 : 128937 PubMed Abstract | Publisher Full Text 11. Egbosiuba TC, Egwunyenga MC, Tijani JO, Mustapha S, et al.: Activated multi-walled carbon nanotubes decorated with zero valent nickel nanoparticles for arsenic, cadmium and lead adsorption from wastewater in a batch and continuous flow modes. J Hazard Mater . 2022; 423 (Pt B): 126993 PubMed Abstract | Publisher Full Text 12. Egbosiuba TC, Abdulkareem AS, Kovo AS, Afolabi EA, et al.: Enhanced adsorption of As(V) and Mn(VII) from industrial wastewater using multi-walled carbon nanotubes and carboxylated multi-walled carbon nanotubes. Chemosphere . 2020; 254 : 126780 PubMed Abstract | Publisher Full Text 13. Egbosiuba TC, Abdulkareem AS, Kovo AS, Afolabi EA, et al.: Adsorption of Cr(VI), Ni(II), Fe(II) and Cd(II) ions by KIAgNPs decorated MWCNTs in a batch and fixed bed process. Sci Rep . 2021; 11 (1): 75 PubMed Abstract | Publisher Full Text 14. De Gisi S, Notarnicola M: Industrial Wastewater Treatment. 2017. 23-42 Publisher Full Text 15. Tijani J, Odeh E, Mustapha S, Egbosiuba T, et al.: Photocatalytic, electrochemical, antibacterial and antioxidant behaviour of carbon-sulphur Co-doped zirconium (IV) oxide nanocomposite. Cleaner Chemical Engineering . 2022; 3 . Publisher Full Text 16. Tijani J, Abdullahi M, Bankole M, Mustapha S, et al.: Photocatalytic and toxicity evaluation of local dyeing wastewater by aluminium/boron doped WO3 nanoparticles. Journal of Water Process Engineering . 2021; 44 . Publisher Full Text 17. Pisello A, Kueppers U, Düffels K, Nomikou P, et al.: The porosity of felsic pyroclasts: laboratory validation of field-based approaches. Bull Volcanol . 2023; 85 (11): 69 PubMed Abstract | Publisher Full Text 18. Abubakar HL, Tijani JO, Abdulkareem AS, Egbosiuba TC, et al.: Effective removal of malachite green from local dyeing wastewater using zinc-tungstate based materials. Heliyon . 2023; 9 (9): e19167 PubMed Abstract | Publisher Full Text Competing Interests No competing interests were disclosed. Reviewer Expertise Materials synthesis for wastewater treatment, Adsorption studies, Kinetic and Isotherm models, Reusability study and the Mechanism of adsorption studies. I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. reply Respond to this report Responses (1) Author Response 13 Apr 2024 JOSE PRATO MORENO, Grupo de Investigación Estudios Interdisciplinarios, Ingeniería Ambiental, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, 060103, Ecuador We thank to the reviewer for their comments Comment 1 : The language of the manuscript must be improved by a native English editor. There are a number of grammatical errors. Response 1: The linguistic aspects of the manuscript in English have undergone a review and necessary corrections. Comment 2 : I suggest the addition of continuous line numbering to enhance review effectiveness. Response 2: The magazine format template does not include continuous numbering in the lines of the manuscript. Comment 3: The abstract must be summarized and rewritten to briefly capture the background, aim of the study, methodology, key results, and the main conclusion. Additional quantification of the results in the abstract is recommended. Response 3: The abstract has been meticulously crafted to align with the stipulated guidelines of the journal (300 words). The information has been expanded following the suggestions given. Notably, the results paragraph incorporates main quantitative data obtained in the research. Comment 4 : In the introduction, describe the hazardous effects of the Pb(II) ions heavy metals. The suggested literatures can guide the authors. Response 4: The introduction has been improved in accordance with the suggestions provided by the reviewer. Comment 5 : I suggest the addition of more treatment techniques such as photocatalysis, adsorption, advanced oxidation process, membrane filtration. Also, each of the mentioned techniques must be referenced. The recommended literature can guide the authors. Response 5: The authors do not intend to provide a comprehensive "state of the art" on lead removal. Nevertheless, we have enhanced the introduction based on the literature recommended by the reviewer. Comment 6 : 2nd paragraph: “Amorphous nanoaluminophosphates have also been proved for lead removing from…” I suggest removing be changed to removal. The entire statement must also be rephrased accordingly. Response 6: The suggested change has been made. Comment 7 : How was the OLM chemically characterized and where are the results?. Response 7: The OLM has undergone both physical and chemical characterization, with the results referenced in the cited literature. However, the authors have chosen to incorporate some of these findings into the methodology section. Comment 8 : Under the preparation of adsorbent, “The lithologic material was crushing…” Crushing or crushed?. Response 4: Correction, the word is “crushed”. Comment 9 : Why use furnace to dry at 150 ºC. Is drying done with furnace or oven?. Response 9: The drying process occurs in two steps: first, air drying for 24 hours, followed by oven drying for an additional 24 hours. These sequential drying steps ensure the complete removal of water from the substrate. Any residual occluded water in the pellet maybe a risk of explosion during the calcination process, leading to the destruction of the pellet. Comment 10 : How is oxides formation favored by calcination?. Response 10: Throughout thermal treatment, oxygen exhibits high reactivity, making surface oxidation the most likely reaction in the substrate. This process is a routine procedure for oxide formation in laboratory settings. “Brett NH. (1991). Magnesium and Alkaline-Earth Oxides. Concise Encyclopedia of Advanced Ceramic Materials. https://doi.org/10.1016/B978-0-08-034720-2.50080-0”. Comment 11 : Kindly remove this statement from the bracket. “(The non-treated...substrate). Response 11: The correction has been made. Comment 12 : The suggested literatures can be used to reference the model equations. Response 12: The literature recommended by the reviewer has been utilized to enhance the references pertaining to adsorption models. Comment 13 : Be consistent in the use of either Pb(II) ions or Pb+2. Response 9: The use of Pb(II) or Pb+2 ions has been revised, following the reviewer's suggestions. Comment 14 : I suggest the removal of grid lines from the graphs. Response 14: Thanks for the suggestion, the authors prefer to use the grid lines because they allow a better visualization of the data in the graphs. Comment 15 : Table 1 and 3 shows the Freundlich and Langmuir isotherm parameters, not fitted equations. Response 15: The table headers have been modified in accordance with the provided suggestions. Comment 16 : Merge Table 1 and 2. Evaluate the qe parameter and present in Table 1. Response 16: Thanks for the suggestion, the authors prefer that the Tables remain separated. Comment 17 : Also merge Table 3 and 4. Response 17: Thanks for the suggestion, the authors prefer that the Tables remain separated. Comment 18 : Under pH and electric conductivity study, “….and activates substrates” Is it activates or activated?. Response 18: Correction: The accurate term is "activated". Comment 19 : There is no conclusion at the end of the manuscript, is that the journal format?. Response 19: The conclusion has been incorporated into the manuscript. Comment 20 : I recommend the following references must be added to enrich the manuscript. Response 20: The references have been downloaded and reviewed. The most pertinent ones have been incorporated into the discussion. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang View more View less Competing Interests No competing interests were disclosed. reply Respond Report a concern Chinedu Egbosiuba T. Peer Review Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.145832.r196306) NOTE: it is important to ensure the information in square brackets after the title is included in this citation. The direct URL for this report is: https://f1000research.com/articles/12-747/v1#referee-response-196306 keyboard_arrow_left Back to all reports Reviewer Report 0 Views copyright © 2023 Wang W. This is an open access peer review report distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 03 Nov 2023 | for Version 1 Wei Wang , Zhengzhou University, Zhengzhou, Henan, China 0 Views copyright © 2023 Wang W. This is an open access peer review report distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. format_quote Cite this report speaker_notes Responses (1) Approved With Reservations info_outline Alongside their report, reviewers assign a status to the article: Approved The paper is scientifically sound in its current form and only minor, if any, improvements are suggested Approved with reservations A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit. Not approved Fundamental flaws in the paper seriously undermine the findings and conclusions This paper presents the adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface. Authors should consider the following observations: 1. Include some novel findings as in numerical results in abstract. 2. The quality of the data analysis is not solid enough. 3. The adsorption mechanism was important and needed to discuss in-depth with characterization support. 4. Compare the present research with the previous literatures. Is the work clearly and accurately presented and does it cite the current literature? Yes Is the study design appropriate and is the work technically sound? Yes Are sufficient details of methods and analysis provided to allow replication by others? Yes If applicable, is the statistical analysis and its interpretation appropriate? Partly Are all the source data underlying the results available to ensure full reproducibility? Partly Are the conclusions drawn adequately supported by the results? Yes Competing Interests No competing interests were disclosed. Reviewer Expertise Mineral material; adsorption; catalyst I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. reply Respond to this report Responses (1) Author Response 13 Apr 2024 JOSE PRATO MORENO, Grupo de Investigación Estudios Interdisciplinarios, Ingeniería Ambiental, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, 060103, Ecuador We thank to the reviewer for their comments Comment 1 : Include some novel findings as in numerical results in abstract. Response 1: The abstract has undergone revision, corrected and structured in accordance with the journal's guidelines. The reported values in the results paragraph, correspond to the main quantitative data obtained in the research. Comment 2 : The quality of the data analysis is not solid enough. Response 2: The manuscript underwent a comprehensive review, leading to enhancements in the presentation of results through the implementation of valuable recommendations provided by the reviewers. Comment 3: The adsorption mechanism was important and needed to discuss in-depth with characterization support. Response 3: The OLM has undergone both physical and chemical characterization, with the results referenced in the published and cited literature. However, the authors have chosen to incorporate some of these findings into the methodology section. Furthermore, in response to the reviewer's valuable suggestions, the enhancement of adsorption results analysis has been achieved. Notably, particular attention has been given to incorporating material characterization in the analysis. Comment 4 : Compare the present research with the previous literatures. Response 4: The results have been compared with other reported investigations and have been added to the paper. Thank you again for your review. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang View more View less Competing Interests No competing interests were disclosed. reply Respond Report a concern Wang W. Peer Review Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.145832.r196304) NOTE: it is important to ensure the information in square brackets after the title is included in this citation. The direct URL for this report is: https://f1000research.com/articles/12-747/v1#referee-response-196304 keyboard_arrow_left Back to all reports Reviewer Report 0 Views copyright © 2023 Dinca N. This is an open access peer review report distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 05 Sep 2023 | for Version 1 Nicolae Dinca , Department of Technical and Natural Sciences, Faculty of Food Engineering, Tourism and Environmental Protection, “Aurel Vlaicu” University, Arad, Romania 0 Views copyright © 2023 Dinca N. This is an open access peer review report distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. format_quote Cite this report speaker_notes Responses (1) Approved With Reservations info_outline Alongside their report, reviewers assign a status to the article: Approved The paper is scientifically sound in its current form and only minor, if any, improvements are suggested Approved with reservations A number of small changes, sometimes more significant revisions are required to address specific details and improve the papers academic merit. Not approved Fundamental flaws in the paper seriously undermine the findings and conclusions The work is topical because it scientifically substantiates the possibility of valorizing some indigenous raw materials in the process of purifying residual waters containing Pb +2 resulting from human activity. The experimental design described on page 4 above, considers the sample volume as a variable factor and the constant Pb +2 concentration (0.001 M), while the results suggest that the sample volume is constant and the concentration is variable. I believe that the confusing text from Methods Adsorption studies (page 4, lines 6-8) should be corrected. Ci is not defined in the text (page 4, line 8). If the values of column n in Table 1 are well calculated, then they do not correspond to equations (1) and (2) in the form of the work dated 26 Jun 2023, 12:74. I believe that these equations should be corrected by replacing n with 1/n . Fig.1 indicates that at low and medium initial ( Ci ) Pb +2 concentrations, the adsorption speeds (at 24h) are higher for the activated material. On page 6, line 5, k 1 and k 2 appear which are not defined in the text and do not appear in eqs. (3-4). K 1 (page 6 line 7) is identical to k 1 from line 5? Technological perspectives that could complement the conclusions (optional): The isotherms in Fig. 1 show that an optimal option in practical applications would be the use of two ion exchange columns linked in series: the first one containing non-activated substrate (cheaper) and the second one containing activated substrate. pH and conductivity measurements can be accessible technical options for monitoring the purification process. Is the work clearly and accurately presented and does it cite the current literature? Yes Is the study design appropriate and is the work technically sound? Yes Are sufficient details of methods and analysis provided to allow replication by others? Partly If applicable, is the statistical analysis and its interpretation appropriate? Yes Are all the source data underlying the results available to ensure full reproducibility? Yes Are the conclusions drawn adequately supported by the results? Yes Competing Interests No competing interests were disclosed. Reviewer Expertise chemistry I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above. reply Respond to this report Responses (1) Author Response 03 Apr 2024 JOSE PRATO MORENO, Grupo de Investigación Estudios Interdisciplinarios, Ingeniería Ambiental, Facultad de Ingeniería, Universidad Nacional de Chimborazo, Riobamba, 060103, Ecuador We thank the reviewer for the importance has given to our research, the time spent correcting the manuscript, their knowledge, experience, and willingness to improve the article. Comment 1 : The experimental design described on page 4 above, considers the sample volume as a variable factor and the constant Pb +2 concentration (0.001 M), while the results suggest that the sample volume is constant and the concentration is variable. I believe that the confusing text from Methods Adsorption studies (page 4, lines 6-8) should be corrected. Response 1: Seven samples of 2 g of substrate, activated and non-activates, were treated with increasing aliquots of 5, 10, 15, 20, 25, 30 and 40 mL of a 1 mM Pb +2 solution. Samples are let to stand, in isothermal conditions, during 24 hours, and periodically shacked. So, the number of millimoles in each one of the samples is known. Comment 2 : Ci is not defined in the text (page 4, line 8). Response 2: It is corrected, defining Ci in the text, section on adsorption studies. Comment 3: If the values of column n in Table 1 are well calculated, then they do not correspond to equations (1) and (2) in the form of the work dated 26 Jun 2023, 12:74. I believe that these equations should be corrected by replacing n with 1/n. Response 3: “n” values are god, what is wrong is equation 2, where exponential term is not n but 1/n. therefore, equations 1 and 2 become: Comment 4 : Fig.1 indicates that at low and medium initial (Ci) Pb +2 concentrations, the adsorption speeds (at 24h) are higher for the activated material. Response 4: Taking into account the observation made, the wording has been modified regarding Fig 1, in the results and discussion sections: Results: Isotherm graph Figure 1 a shows the adsorption isotherms of Pb +2 ions on the activated and non-activated substrates. Although the isotherm profile shows but doesn't confirm information about of the interaction between Pb +2 ions and substrate surface, L -type isotherm is associated with great affinity between sorbent and sorbate. At low equilibrium concentrations, the amount adsorbed increases rapidly, while at high concentrations it decreases, getting to a saturation zone. At low concentration non-activated substrate shows less affinity for Pb +2 ions compared to activated substrate, however, at higher concentration the adsorption isotherm become linear increasing Pb +2 adsorption. It might suggest collateral mechanism for the lead ions adsorption. Discussion: Figure 1 a , shows the isotherm for non-activated substrate. At low concentrations, a similar kind of adsorption but much less intense, showing less affinity for Pb +2 adsorption. However, at higher concentrations, adsorption increases according to a linear model. Most likely acetate ions, being strong base, deprotonates oxides in favor of Pb +2 adsorption, according to the reaction (7) FeOH + CH 3 COO¯ → FeO¯+ CH 3 COOH Therefore, adsorption of Pb +2 ions take place after oxide deprotonation via acetate ion, according to a multilayer physic adsorption model. After all, acetate ions, being a strong base, might compete in the oxide deprotonation to form molecular acetic acid. Comment 5 : On page 6, line 5, k1 and k2 appear which are not defined in the text and do not appear in eqs. (3-4). K1 (page 6 line 7) is identical to k1 from line 5?. Response 5: k 1 and k 2 have been defined in the text and equations 3 and 4 have been adjusted, as detailed below: In equations 3 and 4, q e is the amount adsorbed per adsorbent weight unit, C eq is the equilibrium concentration of adsorbate in solution after adsorption, k 1 is the Langmuir constant related to the affinity between adsorbate and adsorbent, and k 2 is the adsorption capacity, which represents the maximum amount of adsorbate in a monolayer. The parameters of the isotherm are obtained by plotting C eq /q e versus C eq , resulting in a straight line with slope equal to 1/(k 1 * k 2 ) and the intersection equal to 1/k 2 . Thank you again for your review. Sincerely, José G. Prato, Fernando Millán, Marialy Rangel, Andrés Márquez, Luisa Carolina González, Iván Ríos, César García, Carlos Rondón, Enju Wang View more View less Competing Interests No competing interests were disclosed. reply Respond Report a concern Dinca N. Peer Review Report For: Adsorption of Pb (II) ions on variable charge oxidic calcined substrates with chemically modified surface [version 2; peer review: 1 approved, 2 approved with reservations] . F1000Research 2024, 12 :747 ( https://doi.org/10.5256/f1000research.145832.r183567) NOTE: it is important to ensure the information in square brackets after the title is included in this citation. 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