Effective Elimination of Pb (II) Cations from Waste Water and Polluted Water Using Siderite Magnetic Biochar

Effective Elimination of Pb (II) Cations from Waste Water and Polluted Water Using Siderite Magnetic Biochar | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effective Elimination of Pb (II) Cations from Waste Water and Polluted Water Using Siderite Magnetic Biochar Mahsa Sanaei, Saeid Giti Pour, Razyeh Lak, Abdolreza Karbassi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4023493/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Many types of biochars are being used as an adsorbent to remove multiple contaminants, including heavy metals, nutrients and organic compounds from environments. Magnetic biochar composites have been widely used to maximize biochar recycling from aqueous solutions. Magnetic biochar composites were created by pyrolyzing siderite and sawdust in nitrogen gas (N2). adsorption was done in a variety of pH and temperature ranges on magnetic biochar. A magnet was used to extract the MB-liquid from each other following 24-hour shaking period. At Iran's Geological Survey, Pb(II) concentration was measured using an ICP (Inductively Coupled Plasma). The adsorption-desorption process was carried out five times in order to evaluate the magnetic biochar's reusability. The characterizations showed a higher specific surface area and porous structures in the magnetic biochar. An external magnetic field (magnet) was used to easily separate the magnetic biochar suspension because XRD investigation revealed that the primary component of the siderite magnetic biochar absorbent is magnetite, a ferrimagnetic mineral with substantial magnetic characteristics. The magnetic biochar composites' strong adsorption capabilities toward Pb (II) ions were demonstrated by the batch adsorption tests. At pH 5.0 and T = 45°C, Pb had its highest adsorption capability on magnetic biochar. The mesoporous structure of magnetic biochar was indicated by the type IV isotherm. It has been demonstrated that adsorption most closely matches Langmuir's model. Therefore, it can be said that monolayer adsorption has occurred. Biochar's active sites were probably responsible for the fast adsorption process. Kinetics of lead adsorption with MB have been harmonized with pseudo-second order, indicating that the predominant mechanism for Pb adsorption onto magnetic biochar is chemisorption/surface complexation. For Pb(II) environmental remediation, MB adsorbent is suggested to be employed because of its straightforward synthesis process, inexpensive cost, ease of separation, good efficiency and environmental friendliness. Environmental Chemistry Environmental Engineering Adsorption Magnetic Biochar Pb(II) pyrolysis Siderite Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1 Introduction According to [ 1 ] and [ 2 ], lead is one of the carcinogenic elements that can seriously harm human health, cause disorders in children, and raise the chance of mortality. Many industries such as mining, textile dyeing, battery manufacturing, metal electroplating, gasoline burning and fertilizer industry release toxic Lead into the environment through wastewater and untreated waste. Therefore, the Pb(II) concentration must be reduced before release. Adsorption is the most frequently used technology because it is inexpensive and effective [ 3 – 5 ]. Biochar usually created as pyrolyzing organic materials in anoxic conditions, which reduces the volume/mass of trash [ 6 ]. This is because biochar has a very vast exterior area and negative surface charge [ 7 ]. Researches indicate that electrostatic attraction and physiochemical sorption are the ways in which biochar interacts with environmental pollutants. Biochar is a versatile product, but its wide application in wastewater remediation has been hindered by the difficulty of separating it from solutions [ 8 ]. In order to effortlessly extract biochar from an aqueous solution, magnetic biochar was created. Impregnation pyrolysis, co-precipitation, using a reducing agent, and other methods are among the several techniques to create magnetic biochar [ 9 ]. Numerous experiments demonstrated magnetic biochar significantly increased adsorption capacity while also achieving the goal of recycling [ 10 ]. According to investigations, lead prefers attract to the exterior of biochars. The magnetic material used to make the magnetic biochar in this study was natural siderite, which was chosen to lower the production costs and encourage the wider usage of natural minerals. The process of creating magnetic biochar from iron-bearing materials has been documented in a few publications. Siderite has been reported to convert into magnetic minerals [ 11 ] and has been observed that siderite exhibits a range of magnetic properties [ 12 ]. siderite has been the subject of researches on the elimination of toxic cations from environmental medium by [ 13 – 16 ].This study synthesized magnetic biochar from siderite and sawdust and examined its adsorption mechanism for Pb(II). This study has been carried out in the laboratory of Faculty of Environment, University of Tehran and the Geological Survey of Iran (GSI) in 2020. 2 Materials and methods 2.1 MB preparation The natural siderite (Fe 2 O 3 64.50%, FeO 14.90%, SiO 2 9.70%, LOI 8.30%) were obtained from Sangan - Khaf, Iran, and sawdust (C 37.42%, O 38.93%, H 6.04%, N 0.82%, S 0.075%) from Tehran, Iran. At 80°C, the sawdust was dried in an oven. To extract particles with the size of 0.150 − 0.075 mm, the siderite was sieved. After combining siderite and sawdust of 1:2 weight ratio in DI water, suspansion was agitated two hours and after that dried in an oven. The mixture was then put in a biochar reactor in the furnace, which was heated using N 2 for 0.5 hours after reaching 550°C from room temperature. The produced MB granules were removed for characterisation and adsorption studies after cooling to room temperature. Table 1 Chemical composition of siderite chemical composition Fe 2 O 3 FeO SiO 2 Others loss on ignition mass fraction(%) 64.50 14.90 9.70 2.60 8.30 Table 2 Chemical composition of sawdust chemical composition O C H N S mass fraction(%) 38.93 37.42 6.04 0.82 0.075 2.2 Batch experiment To investigate adsorption on MB sample, PbNO 3 solution (100 mg/L Pb 2+ cation) were mixed with 0.1 g of the adsorbent at room temperature (30°C) in a 100 mL backer. In the studies, NaOH or HCl weak solutions were added if needed to change the pH of the test solutions. A shaker was used to spin the backer holding the adsorbent and adsorbate at 30 rpm. A magnet was used to extract the MB-liquid phases following the 24-hour shaking period. At Iran's Geological Survey, the amount of Pb cation was calculated using an ICP (Inductively Coupled Plasma). The effect of temperature (15–60°C) and pH (2–8) on the MB's elimination of Pb(II) was assessed. The adsorption-desorption process was done five cycles to examine the reusability of magnetic biochar. Wet-MB solid was washed with the HCl solution, and the adsorption was then repeated using the cleaned MB. 2.3 Characterization By using a Philips MAGIX PRO XRF-PW2400 X-ray fluorescence spectrometer, the chemical conformation of natural mineral was determined. A Fourier transform infrared spectrometer (FT-IR) (Bruker, WQF-510) was helped to distinguish the structural groups of magnetic biochar. The total content of carbon, nitrogen, oxygen, and hydrogen was obtained using the Eager 300 elemental analyzer (CHN for EA1112). A magnetometer from LBKFB- Kavir Magnetic Co., Kashan, Iran, was used to create the magnetization curve. Dispersive X-ray spectroscopy (EDS) (EDX Oxford UK) and SEM (ZEISS, Germany) scanned the morphology of magnetic biochar. with Cu Kα at 40 mA and 40 kV, an X-ray diffractometer (Bruker, Germany) fitted with a rotation anode was used to examine the mineralogy of magnetic biochar. The (BET) quantified the S BET utilizing N 2 sorption and the TriStar II 1020 equipment. 3 Results and discution 3.1 Characterizations The FT-IR bands seen at 1100 and 1030 cm − 1 are for the C-O stretching vibration, Fig. 1 A [ 17 ]. The C = O and C = C vibrations are associated with the band at 1545 cm − 1 [ 18 ]. bands at 465 and 560 cm − 1 are for Fe-O stretching vibration Fe3O4 [ 19 , 20 ]. The XRD diagram of the pyrolyzed MB is given in Fig. 1 B. The XRD diagram indicates that siderite is changed into magnetite (Fe 3 O 4 ) at 500°C. XRD measurements were used to determine the crystal phase and structural information of the magnetic biochar (Fig. 1 B). Based on XRD analysis, it was found that the siderite magnetic biochar absorbent is mainly composed of magnetite, a ferrimagnetic material with significant magnetic properties, that its black colour defines this well. Therefore, separating magnetic biochar suspension with an external magnetic field (magnet) is simple. The magnetic hysteresis loop of room-temperature magnetic biochar is depicted in Fig. 1 C. Magnetic biochar has a better magnetic response, according to specific saturation magnetization. During the adsorption process, magnetic biochar can be readily separated due to its high magnetic susceptibility [ 21 , 22 ]. Analyzing the morphology of magnetic biochar containing Pb(II) and original magnetic biochar was carried out via SEM-EDS. Magnetite was affixed to the sawdust's porous, fibrous structure in Fig. 1 E. The EDS results showed that these granular nanoparticles were Fe 3 O 4 . Following Pb(II) adsorption, the magnetic biochar's SEM picture (Fig. 1 D) revealed that nanoparticles had been deposited on the porous biochar surface. According to Fig. 2 MB has a IV isotherm, demonstrating the presence of a mesoporous arrangement [ 23 ]. 3.2 Kinetics of Adsorption Adsorption kinetics can demonstrate the rate of adsorption at the interface between solids and solutions. As shown in Fig. 3 Adsorption occurs quickly during the first five hours, and after that, the rate of adsorption gradually increases until equilibrium is attained. The rapid adsorption process is probably caused by magnetic biochar's active sites. The strong adsorption and precipitation of biochar have been reported to contribute to its high performance in accumulating Pb(II) [ 24 , 25 ]. The rapid adsorption rate is thought to be caused by an abundance of active spots, such as wide exterior area as well as rich pore structure [ 26 ]. The kinetic data were used to probe the adsorption procedure in more detail. Table 3 displays the employed sample's adsorption kinetics. Pseudo-second-order model had a higher R 2 than to the pseudo-first-order model. According to [ 27 ], based on kinetics data, pseudo-second-order model, and therefore chemical adsorption is dominating. Table 3 Kinetics for Lead adsorption on MB Sample pseudo-first-order pseudo-second-order MB q e1 (mg∙g − 1 ) K 1 (min − 1 ) R 2 q e2 (mg∙g − 1 ) K 2 (g∙(mg · min) −1 ) R 2 8.32 0.0051 0.8101 16.69 0.0032 0.9483 3.3 Effect of pH The cations of heavy metals adsorption is frequently greatly influenced by solution pH [ 28 ]. this happens because of the ion speciation of heavy metals, chemistry and functional group as well as the surface charge of the adsorbent. To ascertain for impact of medium pH on the MB's efficiency for Pb(II), a pH range of 2 to 8 was chosen. The sorption capacity increased noticeably during pH 2 to 5, as shown in Fig. 4 , and subsequently declined as the pH increased to 8. Figure 5 showed the range of lead species in various pH medium. for pH 8. At high pH values, the quantity of H + decreased, which in turn reduced competition and increased the adsorption capacity. The MB surface develops negative sites, which increases the attraction between the MB surface and cations [ 29 ]. As the pH rose to 6, Pb(II) may not have been able to diffuse to the porous MB's adsorption sites because to the presence and adsorption of Pb(OH) + [ 28 ]. The considerable progress in lead adsorption on MB at pH 2–5 can be attributed to the electrostatic interactions among the positive species of Pb(II) in solution and surface of magnetic biochar with negative charges. Therefore, it is unlikely that electrostatic interactions will cause the progress in lead adsorption by MB at pH 2–5 [ 30 ]. Instead, it is more likely the result of Pb(II) species surface complexation/reduction on magnetic biochar, and the repulsion between negatively charged magnetic biochar and negative Pb(II) species will cause the decrease in lead collection at pH > 5. 3.4 Effect of Temperature Temperature effects revealed that Pb(II) was most able to adsorb onto magnetic biochar at 45°C and least at 15°C (Fig. 6 ). 3.5 Adsorption isotherm The Freundlich and Langmuir models were used to simulate the Pb(II) adsorption isotherm on the MB. According to [ 27 ], the Langmuir model postulates monolayer adsorption on a homogenous surface with a constant number of adsorption sites, meaning that there is no interaction between adsorbed molecules. However, a multilayer adsorption on a heterogeneous adsorbent surface is assumed by the Freundlich model. Langmuir and Freundlich models were used to match the experimental data [ 31 ]. The outcome demonstrated that the superior R 2 of the Langmuir equation (R 2 > 0.95) overfitted the Freundlich model, suggesting that Pb(II) adsorption on MB takes place with Single layer coating. Table 4 displays Freundlich and Langmuir models characteristics. Figure 7 displays the Pb(II) adsorption isotherm in the Langmuir model on the MB. Table 4 Parameters for Langmuir and Freundlich models Sample Langmuir Freundlich q m (mg∙g − 1 ) K L (L·mg − 1 ) R 2 K F (mg·g − 1 ) 1/n R 2 MB 18.32 0.13 0.9525 3.05 0.025 0.8483 When Pb(II) was exposed to magnetic biochar at pH 5.0 and T = 45°C, its maximum adsorption capability was achieved. It has been proven that magnetic biochar is a good sorbent for remediation of lead-contaminated environments and has a good adsorption capacity for Pb(II). For practical applications, magnetic biochar's reusability is essential. Pb(II) has been extensively removed from adsorbents using acid elution. According to Fig. 8 , the amount of lead adsorbed on the MB reduced after five cycles washing with the weak acidic desorption procedure. The small decrease in adsorption quantity was explained by solid loss in solution and incomplete Pb(II) desorption on the magnetic biochar surface. Pb(II) from desorption solutions can also be pre-concentrated and immobilized. 4 Conclusions Our adsorbents were created via heating siderite and sawdust in biochar reactor conditions. This is an economicly, environmentaly and effective process. The performance of the adsorption was greatly enhanced by the pyrolysis. For this occurrence, an increase in surface area should be taken into account. Co-pyrolysis increased the adsorbent's magnetism, which is advantageous for using a magnet to separate solids from liquids. The adsorption tests showed that Pb(II) from environmental medium could be adsorbed with magnetic biochar composites, and that the MB-Pb residue could be simply extracted from the suspension medium with a simple magnet. These findings also showed that magnetic biochar might be a viable substitute for adsorbent in a variety of environmental applications, lowering the danger of Pb(II) contamination. Declarations Funding This work was partly funded by the Geological Survey of Iran (GSI) in 2020. Conflict of interest On behalf of all authors, the corresponding author states that there are no competing interests. Acknowledgements We wish to thank the Geological Survey of Iran (GSI) for their support in every aspect to finalize the present work. References Lu X, Ning XA, Lee PH, Shih K, Wang F, Zeng EY (2017) Transformation of hazardous lead into lead ferrite ceramics: Crystal structures and their role in lead leaching. 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J Hazard Mater 186(1):502–507. https://doi.org/10.1016/j.jhazmat.2010.11.065 Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4023493","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":276930141,"identity":"052ad475-b707-47e2-94c9-09554be1e5bf","order_by":0,"name":"Mahsa Sanaei","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA10lEQVRIiWNgGAWjYFACHgTzwAeStRycQbIWZh7cyhBAt/3s4Q8/GOrkzdkPHzxs23aHgV/6+AW8WszO5KVJ9jAcNtzZk5ZwOLftGYNkX04Bfi0HcsyAbjvAuOFAjgFQy2EGgzM8Cfi1nH9j/PEPQ539hvPvPxy2JErLjRwDaR4G5sQNN3IYDjOCtbAfIKDljZm0jMHh5A03nhkc7Dl3mEeyh0C4mZ3PMf74pqLOdsP55McffpQdluPnYX+AXw8YGCCYQCt4DHCrxAGIsmUUjIJRMApGEAAAd/FKt/RlhMcAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0003-3704-865X","institution":"University of Tehran Faculty of Environment","correspondingAuthor":true,"prefix":"","firstName":"Mahsa","middleName":"","lastName":"Sanaei","suffix":""},{"id":276930142,"identity":"ea73141d-07d2-4122-a420-69cb7e9313c7","order_by":1,"name":"Saeid Giti Pour","email":"","orcid":"https://orcid.org/0000-0002-0694-7110","institution":"University of Tehran Faculty of Environment","correspondingAuthor":false,"prefix":"","firstName":"Saeid","middleName":"Giti","lastName":"Pour","suffix":""},{"id":276930143,"identity":"ed822ec3-4870-4992-8ac8-683144fca1d3","order_by":2,"name":"Razyeh Lak","email":"","orcid":"https://orcid.org/0000-0003-3223-5528","institution":"Geological Survey and Mineral Exploration of Iran","correspondingAuthor":false,"prefix":"","firstName":"Razyeh","middleName":"","lastName":"Lak","suffix":""},{"id":276930144,"identity":"b0daa16f-0a85-4ef4-890a-693685e82917","order_by":3,"name":"Abdolreza Karbassi","email":"","orcid":"https://orcid.org/0000-0001-9300-7620","institution":"University of Tehran Faculty of Environment","correspondingAuthor":false,"prefix":"","firstName":"Abdolreza","middleName":"","lastName":"Karbassi","suffix":""}],"badges":[],"createdAt":"2024-03-07 08:11:02","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":true,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":true},"doi":"10.21203/rs.3.rs-4023493/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4023493/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":52244457,"identity":"ef6d9e98-86de-4494-8de5-7c631310c29c","added_by":"auto","created_at":"2024-03-08 08:26:32","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":424164,"visible":true,"origin":"","legend":"\u003cp\u003eMagnetic biochar's characteristics. A: FTIR spectra; B: XRD patterns; C: magnetic hysteresis loops; D \u0026amp; E: SEM images.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4023493/v1/4ec92f215d428f2ff50af3ba.png"},{"id":52244313,"identity":"2e81e9e6-b7e8-4a06-8744-14e763d25101","added_by":"auto","created_at":"2024-03-08 08:18:31","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":66612,"visible":true,"origin":"","legend":"\u003cp\u003eN\u003csub\u003e2\u003c/sub\u003e-adsorption-desorption isotherm\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4023493/v1/676b681e3620cdb374419b7b.png"},{"id":52244315,"identity":"cca887c6-94f0-4818-adff-1ed4917c4c1a","added_by":"auto","created_at":"2024-03-08 08:18:31","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":57158,"visible":true,"origin":"","legend":"\u003cp\u003eleft: kinetics of Lead on magnetic biochar, right: pseudo-second-order model\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4023493/v1/4dcb9d0dbc2393fe32756853.png"},{"id":52244456,"identity":"7448162e-8ea5-4e15-a0d0-3030fee80a80","added_by":"auto","created_at":"2024-03-08 08:26:31","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":33165,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of pH on MB adsorption\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-4023493/v1/80fe1ea8a31f1de3fd8b47bb.png"},{"id":52244320,"identity":"c9934038-f490-4f54-8f9c-0d30b6c9574e","added_by":"auto","created_at":"2024-03-08 08:18:32","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":248004,"visible":true,"origin":"","legend":"\u003cp\u003eLead species Distribution in different pH\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-4023493/v1/c2b8c5b3ef25a6ff4c344719.png"},{"id":52244316,"identity":"f3be413d-7de4-45da-ace4-514da535492f","added_by":"auto","created_at":"2024-03-08 08:18:31","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":36666,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of temperature on magnetic biochar adsorption.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-4023493/v1/1a5746ba0f056fe4ad31268c.png"},{"id":52244604,"identity":"4ed4f71e-cf6f-4a34-ade5-2932eced088e","added_by":"auto","created_at":"2024-03-08 08:34:32","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":38980,"visible":true,"origin":"","legend":"\u003cp\u003eAdsorption isotherm\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-4023493/v1/bc44e8e4ce9ee7c5e9b16f0b.png"},{"id":52244319,"identity":"48c445b1-f347-4459-bf1a-788b389bdf7b","added_by":"auto","created_at":"2024-03-08 08:18:32","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":18797,"visible":true,"origin":"","legend":"\u003cp\u003ecycle experiments of Pb(II) adsorption on MB\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-4023493/v1/16fd02cfda3b6bf0cbd2e13c.png"},{"id":52246993,"identity":"3cfd00a1-936c-4995-aa2d-2a3884e1b9f3","added_by":"auto","created_at":"2024-03-08 08:42:32","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1119877,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4023493/v1/8388c2c1-d2f2-4dc9-86dd-628211bebaee.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eEffective Elimination of Pb (II) Cations from Waste Water and Polluted Water Using Siderite Magnetic Biochar\u003c/p\u003e","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eAccording to [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] and [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], lead is one of the carcinogenic elements that can seriously harm human health, cause disorders in children, and raise the chance of mortality. Many industries such as mining, textile dyeing, battery manufacturing, metal electroplating, gasoline burning and fertilizer industry release toxic Lead into the environment through wastewater and untreated waste. Therefore, the Pb(II) concentration must be reduced before release. Adsorption is the most frequently used technology because it is inexpensive and effective [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Biochar usually created as pyrolyzing organic materials in anoxic conditions, which reduces the volume/mass of trash [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. This is because biochar has a very vast exterior area and negative surface charge [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Researches indicate that electrostatic attraction and physiochemical sorption are the ways in which biochar interacts with environmental pollutants. Biochar is a versatile product, but its wide application in wastewater remediation has been hindered by the difficulty of separating it from solutions [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn order to effortlessly extract biochar from an aqueous solution, magnetic biochar was created. Impregnation pyrolysis, co-precipitation, using a reducing agent, and other methods are among the several techniques to create magnetic biochar [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Numerous experiments demonstrated magnetic biochar significantly increased adsorption capacity while also achieving the goal of recycling [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAccording to investigations, lead prefers attract to the exterior of biochars. The magnetic material used to make the magnetic biochar in this study was natural siderite, which was chosen to lower the production costs and encourage the wider usage of natural minerals.\u003c/p\u003e \u003cp\u003eThe process of creating magnetic biochar from iron-bearing materials has been documented in a few publications. Siderite has been reported to convert into magnetic minerals [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] and has been observed that siderite exhibits a range of magnetic properties [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. siderite has been the subject of researches on the elimination of toxic cations from environmental medium by [\u003cspan additionalcitationids=\"CR14 CR15\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].This study synthesized magnetic biochar from siderite and sawdust and examined its adsorption mechanism for Pb(II).\u003c/p\u003e \u003cp\u003eThis study has been carried out in the laboratory of Faculty of Environment, University of Tehran and the Geological Survey of Iran (GSI) in 2020.\u003c/p\u003e"},{"header":"2 Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 MB preparation\u003c/h2\u003e \u003cp\u003eThe natural siderite (Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e 64.50%, FeO 14.90%, SiO\u003csub\u003e2\u003c/sub\u003e 9.70%, LOI 8.30%) were obtained from Sangan - Khaf, Iran, and sawdust (C 37.42%, O 38.93%, H 6.04%, N 0.82%, S 0.075%) from Tehran, Iran. At 80\u0026deg;C, the sawdust was dried in an oven. To extract particles with the size of 0.150\u0026thinsp;\u0026minus;\u0026thinsp;0.075 mm, the siderite was sieved. After combining siderite and sawdust of 1:2 weight ratio in DI water, suspansion was agitated two hours and after that dried in an oven. The mixture was then put in a biochar reactor in the furnace, which was heated using N\u003csub\u003e2\u003c/sub\u003e for 0.5 hours after reaching 550\u0026deg;C from room temperature. The produced MB granules were removed for characterisation and adsorption studies after cooling to room temperature.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eChemical composition of siderite\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003echemical composition\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFeO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eOthers\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eloss on ignition\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003emass fraction(%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e64.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e8.30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eChemical composition of sawdust\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003echemical composition\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eH\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eS\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003emass fraction(%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e37.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.075\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Batch experiment\u003c/h2\u003e \u003cp\u003eTo investigate adsorption on MB sample, PbNO\u003csub\u003e3\u003c/sub\u003e solution (100 mg/L Pb\u003csup\u003e2+\u003c/sup\u003e cation) were mixed with 0.1 g of the adsorbent at room temperature (30\u0026deg;C) in a 100 mL backer. In the studies, NaOH or HCl weak solutions were added if needed to change the pH of the test solutions. A shaker was used to spin the backer holding the adsorbent and adsorbate at 30 rpm. A magnet was used to extract the MB-liquid phases following the 24-hour shaking period. At Iran's Geological Survey, the amount of Pb cation was calculated using an ICP (Inductively Coupled Plasma).\u003c/p\u003e \u003cp\u003eThe effect of temperature (15\u0026ndash;60\u0026deg;C) and pH (2\u0026ndash;8) on the MB's elimination of Pb(II) was assessed. The adsorption-desorption process was done five cycles to examine the reusability of magnetic biochar. Wet-MB solid was washed with the HCl solution, and the adsorption was then repeated using the cleaned MB.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Characterization\u003c/h2\u003e \u003cp\u003eBy using a Philips MAGIX PRO XRF-PW2400 X-ray fluorescence spectrometer, the chemical conformation of natural mineral was determined. A Fourier transform infrared spectrometer (FT-IR) (Bruker, WQF-510) was helped to distinguish the structural groups of magnetic biochar. The total content of carbon, nitrogen, oxygen, and hydrogen was obtained using the Eager 300 elemental analyzer (CHN for EA1112). A magnetometer from LBKFB- Kavir Magnetic Co., Kashan, Iran, was used to create the magnetization curve. Dispersive X-ray spectroscopy (EDS) (EDX Oxford UK) and SEM (ZEISS, Germany) scanned the morphology of magnetic biochar. with Cu Kα at 40 mA and 40 kV, an X-ray diffractometer (Bruker, Germany) fitted with a rotation anode was used to examine the mineralogy of magnetic biochar. The (BET) quantified the S\u003csub\u003eBET\u003c/sub\u003e utilizing N\u003csub\u003e2\u003c/sub\u003e sorption and the TriStar II 1020 equipment.\u003c/p\u003e \u003c/div\u003e"},{"header":"3 Results and discution","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Characterizations\u003c/h2\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe FT-IR bands seen at 1100 and 1030 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e are for the C-O stretching vibration, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The C\u0026thinsp;=\u0026thinsp;O and C\u0026thinsp;=\u0026thinsp;C vibrations are associated with the band at 1545 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. bands at 465 and 560 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e are for Fe-O stretching vibration Fe3O4 [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe XRD diagram of the pyrolyzed MB is given in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB. The XRD diagram indicates that siderite is changed into magnetite (Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e) at 500\u0026deg;C. XRD measurements were used to determine the crystal phase and structural information of the magnetic biochar (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB). Based on XRD analysis, it was found that the siderite magnetic biochar absorbent is mainly composed of magnetite, a ferrimagnetic material with significant magnetic properties, that its black colour defines this well. Therefore, separating magnetic biochar suspension with an external magnetic field (magnet) is simple.\u003c/p\u003e \u003cp\u003eThe magnetic hysteresis loop of room-temperature magnetic biochar is depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eC. Magnetic biochar has a better magnetic response, according to specific saturation magnetization. During the adsorption process, magnetic biochar can be readily separated due to its high magnetic susceptibility [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAnalyzing the morphology of magnetic biochar containing Pb(II) and original magnetic biochar was carried out via SEM-EDS. Magnetite was affixed to the sawdust's porous, fibrous structure in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eE. The EDS results showed that these granular nanoparticles were Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e. Following Pb(II) adsorption, the magnetic biochar's SEM picture (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eD) revealed that nanoparticles had been deposited on the porous biochar surface.\u003c/p\u003e \u003cp\u003eAccording to Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e MB has a IV isotherm, demonstrating the presence of a mesoporous arrangement [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e\u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Kinetics of Adsorption\u003c/h2\u003e \u003cp\u003eAdsorption kinetics can demonstrate the rate of adsorption at the interface between solids and solutions. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e Adsorption occurs quickly during the first five hours, and after that, the rate of adsorption gradually increases until equilibrium is attained. The rapid adsorption process is probably caused by magnetic biochar's active sites.\u003c/p\u003e \u003cp\u003eThe strong adsorption and precipitation of biochar have been reported to contribute to its high performance in accumulating Pb(II) [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The rapid adsorption rate is thought to be caused by an abundance of active spots, such as wide exterior area as well as rich pore structure [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe kinetic data were used to probe the adsorption procedure in more detail. Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e displays the employed sample's adsorption kinetics.\u003c/p\u003e \u003cp\u003ePseudo-second-order model had a higher R\u003csup\u003e2\u003c/sup\u003e than to the pseudo-first-order model. According to [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], based on kinetics data, pseudo-second-order model, and therefore chemical adsorption is dominating.\u003c/p\u003e\u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eKinetics for Lead adsorption on MB\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003epseudo-first-order\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e \u003cp\u003epseudo-second-order\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eq\u003csub\u003ee1\u003c/sub\u003e\u003c/p\u003e \u003cp\u003e(mg∙g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eK\u003csub\u003e1\u003c/sub\u003e\u003c/p\u003e \u003cp\u003e(min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eq\u003csub\u003ee2\u003c/sub\u003e\u003c/p\u003e \u003cp\u003e(mg∙g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eK\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003cp\u003e(g∙(mg\u0026nbsp;\u0026middot;\u0026nbsp;min)\u003csup\u003e\u0026minus;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.0051\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.8101\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e16.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.0032\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.9483\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Effect of pH\u003c/h2\u003e \u003cp\u003eThe cations of heavy metals adsorption is frequently greatly influenced by solution pH [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. this happens because of the ion speciation of heavy metals, chemistry and functional group as well as the surface charge of the adsorbent. To ascertain for impact of medium pH on the MB's efficiency for Pb(II), a pH range of 2 to 8 was chosen. The sorption capacity increased noticeably during pH 2 to 5, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003e, and subsequently declined as the pH increased to 8.\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003e showed the range of lead species in various pH medium. for pH\u0026thinsp;\u0026lt;\u0026thinsp;4, Pb\u003csup\u003e2+\u003c/sup\u003e was the predominant Pb(II) species. Cations of lead, like Pb(OH)\u003csup\u003e+\u003c/sup\u003e, were detected between pH 4 and 8, whereas anions of lead, like HPbO\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, and the hydroxide Pb(OH)\u003csub\u003e2\u003c/sub\u003e were detected at pH\u0026thinsp;\u0026gt;\u0026thinsp;8. At high pH values, the quantity of H\u003csup\u003e+\u003c/sup\u003e decreased, which in turn reduced competition and increased the adsorption capacity. The MB surface develops negative sites, which increases the attraction between the MB surface and cations [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. As the pH rose to 6, Pb(II) may not have been able to diffuse to the porous MB's adsorption sites because to the presence and adsorption of Pb(OH)\u003csup\u003e+\u003c/sup\u003e [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe considerable progress in lead adsorption on MB at pH 2\u0026ndash;5 can be attributed to the electrostatic interactions among the positive species of Pb(II) in solution and surface of magnetic biochar with negative charges. Therefore, it is unlikely that electrostatic interactions will cause the progress in lead adsorption by MB at pH 2\u0026ndash;5 [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Instead, it is more likely the result of Pb(II) species surface complexation/reduction on magnetic biochar, and the repulsion between negatively charged magnetic biochar and negative Pb(II) species will cause the decrease in lead collection at pH\u0026thinsp;\u0026gt;\u0026thinsp;5.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Effect of Temperature\u003c/h2\u003e \u003cp\u003eTemperature effects revealed that Pb(II) was most able to adsorb onto magnetic biochar at 45\u0026deg;C and least at 15\u0026deg;C (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Adsorption isotherm\u003c/h2\u003e \u003cp\u003eThe Freundlich and Langmuir models were used to simulate the Pb(II) adsorption isotherm on the MB. According to [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e], the Langmuir model postulates monolayer adsorption on a homogenous surface with a constant number of adsorption sites, meaning that there is no interaction between adsorbed molecules. However, a multilayer adsorption on a heterogeneous adsorbent surface is assumed by the Freundlich model.\u003c/p\u003e \u003cp\u003eLangmuir and Freundlich models were used to match the experimental data [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The outcome demonstrated that the superior R\u003csup\u003e2\u003c/sup\u003e of the Langmuir equation (R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.95) overfitted the Freundlich model, suggesting that Pb(II) adsorption on MB takes place with Single layer coating.\u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e displays Freundlich and Langmuir models characteristics. Figure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e displays the Pb(II) adsorption isotherm in the Langmuir model on the MB.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eParameters for Langmuir and Freundlich models\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLangmuir\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eFreundlich\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eq\u003csub\u003em\u003c/sub\u003e\u003c/p\u003e \u003cp\u003e(mg∙g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eK\u003csub\u003eL\u003c/sub\u003e\u003c/p\u003e \u003cp\u003e(L\u0026middot;mg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eK\u003csub\u003eF\u003c/sub\u003e\u003c/p\u003e \u003cp\u003e(mg\u0026middot;g\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1/n\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.9525\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.8483\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eWhen Pb(II) was exposed to magnetic biochar at pH 5.0 and T\u0026thinsp;=\u0026thinsp;45\u0026deg;C, its maximum adsorption capability was achieved. It has been proven that magnetic biochar is a good sorbent for remediation of lead-contaminated environments and has a good adsorption capacity for Pb(II).\u003c/p\u003e \u003cp\u003eFor practical applications, magnetic biochar's reusability is essential. Pb(II) has been extensively removed from adsorbents using acid elution. According to Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e, the amount of lead adsorbed on the MB reduced after five cycles washing with the weak acidic desorption procedure. The small decrease in adsorption quantity was explained by solid loss in solution and incomplete Pb(II) desorption on the magnetic biochar surface. Pb(II) from desorption solutions can also be pre-concentrated and immobilized.\u003c/p\u003e \u003c/div\u003e"},{"header":"4 Conclusions","content":"\u003cp\u003eOur adsorbents were created via heating siderite and sawdust in biochar reactor conditions. This is an economicly, environmentaly and effective process. The performance of the adsorption was greatly enhanced by the pyrolysis. For this occurrence, an increase in surface area should be taken into account. Co-pyrolysis increased the adsorbent's magnetism, which is advantageous for using a magnet to separate solids from liquids.\u003c/p\u003e \u003cp\u003eThe adsorption tests showed that Pb(II) from environmental medium could be adsorbed with magnetic biochar composites, and that the MB-Pb residue could be simply extracted from the suspension medium with a simple magnet. These findings also showed that magnetic biochar might be a viable substitute for adsorbent in a variety of environmental applications, lowering the danger of Pb(II) contamination.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was partly funded by the Geological Survey of Iran (GSI) in 2020.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOn behalf of all authors, the corresponding author states that there are no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe wish to thank the Geological Survey of Iran (GSI) for their support in every aspect to finalize the present work.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLu X, Ning XA, Lee PH, Shih K, Wang F, Zeng EY (2017) Transformation of hazardous lead into lead ferrite ceramics: Crystal structures and their role in lead leaching. 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J Hazard Mater 186(1):502\u0026ndash;507. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jhazmat.2010.11.065\u003c/span\u003e\u003cspan address=\"10.1016/j.jhazmat.2010.11.065\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[{"identity":"e4a0062f-aee3-4471-a100-18886be7f738","identifier":"10.13039/501100014829","name":"Geological Survey and Mineral Exploration of Iran","awardNumber":"500-4325 ","order_by":0}],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"University of Tehran","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Adsorption, Magnetic Biochar, Pb(II), pyrolysis, Siderite","lastPublishedDoi":"10.21203/rs.3.rs-4023493/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4023493/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMany types of biochars are being used as an adsorbent to remove multiple contaminants, including heavy metals, nutrients and organic compounds from environments. Magnetic biochar composites have been widely used to maximize biochar recycling from aqueous solutions.\u003c/p\u003e \u003cp\u003eMagnetic biochar composites were created by pyrolyzing siderite and sawdust in nitrogen gas (N2). adsorption was done in a variety of pH and temperature ranges on magnetic biochar. A magnet was used to extract the MB-liquid from each other following 24-hour shaking period. At Iran's Geological Survey, Pb(II) concentration was measured using an ICP (Inductively Coupled Plasma). The adsorption-desorption process was carried out five times in order to evaluate the magnetic biochar's reusability.\u003c/p\u003e \u003cp\u003eThe characterizations showed a higher specific surface area and porous structures in the magnetic biochar. An external magnetic field (magnet) was used to easily separate the magnetic biochar suspension because XRD investigation revealed that the primary component of the siderite magnetic biochar absorbent is magnetite, a ferrimagnetic mineral with substantial magnetic characteristics. The magnetic biochar composites' strong adsorption capabilities toward Pb (II) ions were demonstrated by the batch adsorption tests. At pH 5.0 and T\u0026thinsp;=\u0026thinsp;45\u0026deg;C, Pb had its highest adsorption capability on magnetic biochar. The mesoporous structure of magnetic biochar was indicated by the type IV isotherm. It has been demonstrated that adsorption most closely matches Langmuir's model. Therefore, it can be said that monolayer adsorption has occurred. Biochar's active sites were probably responsible for the fast adsorption process. Kinetics of lead adsorption with MB have been harmonized with pseudo-second order, indicating that the predominant mechanism for Pb adsorption onto magnetic biochar is chemisorption/surface complexation.\u003c/p\u003e \u003cp\u003eFor Pb(II) environmental remediation, MB adsorbent is suggested to be employed because of its straightforward synthesis process, inexpensive cost, ease of separation, good efficiency and environmental friendliness.\u003c/p\u003e","manuscriptTitle":"Effective Elimination of Pb (II) Cations from Waste Water and Polluted Water Using Siderite Magnetic Biochar","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-03-08 08:18:27","doi":"10.21203/rs.3.rs-4023493/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"1eb0522b-dab4-485e-8048-9123cbac931d","owner":[],"postedDate":"March 8th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":29187309,"name":"Environmental Chemistry"},{"id":29187310,"name":"Environmental Engineering"}],"tags":[],"updatedAt":"2025-01-24T09:38:25+00:00","versionOfRecord":[],"versionCreatedAt":"2024-03-08 08:18:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4023493","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4023493","identity":"rs-4023493","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}