Green Solutions for Soil Contamination: Sustainable Production and Characterization of Nano-Biochar from Sugarcane Bagasse and Olive Mill Waste

Green Solutions for Soil Contamination: Sustainable Production and Characterization of Nano-Biochar from Sugarcane Bagasse and Olive Mill Waste | 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 Green Solutions for Soil Contamination: Sustainable Production and Characterization of Nano-Biochar from Sugarcane Bagasse and Olive Mill Waste Salah Radwan, El-Husieny Abou Hussien, Basma Ahmed, Nehal Ali This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4430795/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 Purpose This study examines the production of biochar from sugarcane bagasse and olive mill waste, focusing on its elemental composition, form, and functional groups, and its impact on soil immobilization. Methods The study utilized various techniques like SEM, TEM, and FTIR to describe the biochars produced from SCB and OMW, which were prepared through ball-milling and activation treatments. Results The study explores KOH interaction pathways during biomass pyrolysis, revealing larger surface areas and consistent decrease in soil trace element levels. Conclusions This study introduces ZnCl 2 chemical activation and activated carbon samples, enhancing understanding of activation procedures and biochar nanoparticles' benefits. It offers a green, sustainable solution to soil contamination. Nano biochar Elemental composition Soil immobilization and Activation Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 1. Introduction Soil contamination due to herbicides, pesticides, antibiotics, and sewage-contaminated water poses a significant environmental threat. Sorption offers an efficient solution due to its adaptability, competitive performance, and simplicity. One of these primary consequences is soil contamination with trace elements (TEs), which is primarily caused by human activity. These activities include mining and the widespread use of industrial waste, sewage sludge, fertilizer, and pesticides, notably in agriculture. TEs comprise both biologically vital elements like zinc (Zn), cobalt (Co), copper (Cu), and manganese (Mn) and non-essential elements like cadmium (Cd), chromium (Cr), arsenic (As), and lead (Pb). Essential elements are necessary in trace amounts for proper plant and animal growth and development, and are thus referred to as micronutrients. However, in large quantities, these metals are toxic to living organisms ( Mohamed et al., 2022 ). Soil contamination with trace elements (TEs) is a major consequence of human activities like mining and industrial waste, particularly in agriculture. These toxic metals, produced annually in Egypt, pose resource optimization opportunities. ( Shaaban and Nasr, 2018 ) . Previous research has demonstrated that soil contaminated with lead (Pb), nickel (Ni), and molybdenum (Mo) among other metals. According to certain theories, excessive amounts of Pb, Ni, and Mo in these elements might affect vegetables and result in toxicological issues for adults and children. Heavy metal soil remediation methods, including excavation, washing procedures, landfilling, and solidification of the soil, can be costly and labor-intensive. As an alternative to landfilling, excavation, and other forms of soil remediation, in situ methods like the immobilization of heavy metals may be less expensive and have a smaller negative ecological impact. Biological, physical, and chemical methods can be used to remediate polluted soils that contain immobilized heavy metals The main objective of immobilizing heavy metals by the addition of amendments to polluted soils is to decrease metal mobility and toxicity through metal sorption and precipitation, rather than to change the total metal content. In order to adsorb metals in soil and water, carbon-rich supplements like compost and biochar have recently been employed as innovative carbonaceous materials and commercially viable technologies (Almaroai et al. 2014). Nanobiochar has found wide-ranging uses, such as a material for removing contaminants, a catalyst, a carrier of biomolecules, an electrode material, a sensing material, a substitute for carbon black, and a material for the battery sector. Moreover, rice and wheat may be grown more rapidly with the use of nanobiochar as a growing medium. The majority of studies on nanobiochar concentrate on its application as an adsorbent substance. It has been investigated how well nanobiochar removes a variety of materials, including as agrochemicals, medicines, potentially hazardous materials, and organic and inorganic molecules. One of the primary obstacles to commercializing the product is the extremely low yield of nanobiochar produced by the other methods, with the exception of ball-milling, which produces nanobiochar as a direct end product ( Zheng et al., 2020 ). Furthermore, transferring from the lab to the industrial scale could result in a variety of problems throughout the milling process. Thus, more research on marketable nanobiochar is required, as well as a techno-economic study ( Zheng et al., 2020 ). When it came to the adsorption of organic molecules like carbamazepine, pinewood nanobiochar showed greater capabilities than carbonaceous materials like carbon nanotubes, activated carbon, and graphene oxides (95%). High surface area, graphitic composition, variably charged functional groups, and components like humic acid are the foundation of nanobiochar's adsorption potential. Examining hardwood nanobiochar's ability to eliminate both organic and inorganic micropollutants Ramanayaka et al. (2020) , who, as a result of the existence of various functional groups such –OH, C = O, and –NH, showed high removal capabilities of 83, 520, 922, and 7.46 mg g-1 for glyphosate, oxytetracycline, Cd(II), and Cr(VI), respectively. The main factors influencing the surface functional groups in nanobiochar are the temperature during pyrolysis and the kind of feedstock. The material's volatile organic chemicals may devolatilize as a result of the rising temperature, which will reduce the amount of surface functional groups. Nonetheless, research indicates that compared to unmilled virgin biochar (0.8–2.9 mmol g–1), ball-milled biochar has a higher concentration of oxygen-containing functional groups (2.2–4.4 mmol g–1) Cao et al. ( 2011 ). In addition, following ball-milling, there are more acidic surface functional groups, which improves adsorption effectiveness. Additionally, milling reveals the graphitic character of the nanobiochar and causes the production of reactive oxygen species (ROS), which may enhance the surface chemistry of the biochar relative to its pristine state. The surface functional groups have been identified by most research using FTIR spectroscopy, and others have utilized Boehm titration to quantify those groups. Acidic functional group concentrations in bagasse biochar were shown to rise after milling, from 0.8 to 2.5 mmol g-1 ( Wallace et al. 2019 ). Such pollutants in water may be transported by nanobiochar. The high ROS content of nanobiochar may have an impact on the deterioration of organic materials like oxytetracycline and glyphosate. Nevertheless, there is a dearth of information regarding the adsorption process's organic pollutant degradation in the presence of ROS. Enhancing the adsorption capacity of biochar can also be achieved by modifying its mechanical, chemical, and physical properties. Pinewood nano biochar's adsorption capability can be increased by 57% by employing a surfactant to change the pH of the solution from acidic to basic. The adsorption performance of goethite-modified peanut shell nanobiochar was improved through the formation of intercalated hetero structures and hetero aggregation Ramanayaka et al. (2020) . Further modification of nano biochar chemical and physical properties can be achieved through process defined “activation”, aimed at increasing nano biochar porosity and modifying its pore size distribution, as well as to some extent surface chemistry ( Shafiq et al., 2023 ). Activation can be carried out in a number of ways, depending on type of activation agents (e.g. physical and chemical activation) or mode of operation into single-stage or multi-stage activation. Chemical activation utilizes chemical agents, e.g., H 3 PO 4 , HNO 3 , KOH, NaOH, H 2 SO 4 , and ZnCl 2 ( Tan et al., 2017 ). It typically involves two steps; in the first the feedstock is impregnated with a selected chemical agent, and then thermally treated in the second step. Another option is the activation of already produced biochar by soaking it in a chemical agent, followed by a thermal treatment ( Lehmann and Joseph, 2015 ) . Depending on the agent selected and thermal treatment conditions used, different degrees of activation can be achieved. The activated nano biochar needs to be thoroughly washed with deionized water to neutralize its pH and to remove any remaining chemicals, and this procedure can contribute to a negative environmental impact of the technology. Oxidative activation that uses acidic or alkaline agents is among the most common activation methods. Besides enhancing porosity and surface area, it also creates oxygen-containing functional groups on the surface of biochar (e.g. carboxyl, hydroxyl, lactone, phenol, carbonyl, and peroxide groups) (Wongrod et al., 2020) . The properties of biochar, including surface area, porosity, and functional groups, significantly influence its adsorption performance ( Jang et al., 2018 ). These properties depend on factors like feedstock, pyrolysis conditions, and post-treatment modifications such as sulphonation, amination, oxidation, and metal nanoparticle impregnation ( Tan et al., 2017 ). Some studies have shown that salt chlorides like ZnCl 2 can enhance carbon porosity more effectively than certain acids and bases ( Ateş and Özcan, 2018 ) . Activators like ZnCl 2 have also been found to increase pore volume in the 2–10 nm range. Additionally, FeCl 3 , as an activator, has improved biochar yield, granule strength, and adsorption capabilities. Nano biochar properties, including surface area, porosity, and functional groups, significantly influence adsorption performance, influenced by factors like feedstock, pyrolysis conditions, and post-treatment modifications. ( Ateş and Özcan, 2018 ) . This study aimed to produce nanobiochar from sugarcane bagasse (SCB) and olive mill waste (OMW) via pyrolysis, analyzing their composition, functional groups, and morphology. It explored KOH and ZnCl 2 chemical activation methods for the nanobiochar produced from both resources, revealing new understanding about their mechanisms and effectiveness in reducing environmental toxicity TE(s). 2. Materials and Methods 2.1 Agricultural Waste The biochar was made from sugarcane bagasse and olive mill waste, obtained from a Sadat City facility in Egypt. The waste was prepared by cutting, washing, and drying in an oven. Pyrolysis Procedure In Soil Science Department at Menofia University conducted pyrolysis experiments on agricultural wastes using a stainless steel chamber heated with a muffle furnace. The biomass was subjected to temperatures ranging from 400˚C to 550˚C for 90 minutes under oxygen-free conditions. Nano Biochar Fabrication through Milling The nano biochar was prepared using a ball-milling technique, grounding sugarcane bagasse and olive mill waste in 180g of agate balls at 350°C for 12 hours. ( Amusat et al., 2021 ). 2.2 Chemical Activation Procedures Activation with KOH The biochar was chemically activated using Wongrod in 2020 method, which involved adding 2 grams of biochar to a 250 ml conical flask, shaking for 2 hours, and then rinsing with deionized water, repeating the process 3–4 times until the pH level stabilized. Activation with ZnCl2 Uemura et al.'s 2012 method for activating biochar involved soaking 10 grams of biochar in a 1 M ZnCl2 solution, drying it in an oven, stirring it in a 0.10 M HCl solution, washing it with hot deionized water, and drying it overnight at 110 ⁰C. 2.3 Experimental design The experiment was set up in completely randomized design (CRD) consisting of twelve (12) treatment combinations SCBNK 0, SCBNK 0.4, SCBNK 0.6, SCBNK 0.8, SCBNZ 0, SCBNZ 0.4, SCBNZ 0.6, SCBNZ 0.8, OMWNK 0, OMWNK 0.4, OMWNK 0.6, OMWNK 0.8, OMWNZ 0, OMWNZ 0.4, OMWNZ 0.6, OMWNZ 0.8,where SCB indicates biochar from sugar cane bagasse, OMW indicates biochar from olive mill waste, N indicates nano size, K indicates to KOH activation, Z indicates to ZnCl 2 activation and 0, 0.4, 0.6 and 0.8% indicates to application rate. 2.4 Experimental procedures Soil was mixed with amendment at different rates, incubated for 40 days, and wetted with distilled water daily. The control soil remained unaffected. 2.4.1 Ultimate and Proximate Analysis of Biochar and Residues The analysis of biochar and residue samples involved determining C, N, and H percentage contents, assessing ash and volatile matter content, and observing weight loss post-combustion to provide insights into these components by ( McLaughlin et al. 2012 ). 2.4.2 Physico-Chemical Analysis of Biochar Biochar Characteristics analysis of biochar involved determining pH, EC, and elemental composition, including carbon, oxygen, hydrogen, nitrogen, calcium, magnesium, and potassium (Singh et al.'s 2017 ) . Micronutrients and Heavy Metals The biochar's micronutrients and heavy metals levels were assessed using a method by ( Lindsay and Norvell, 1978 ) followed by atomic absorption spectrophotometry using the NovAA800®F model. Morphological and Crystal Properties Morphological examination of biochar using SEM imaging and TEM analysis after sonication in ethanol, using Hitachi TM-1000 device and two different TEM devices. Surface Chemistry FTIR spectroscopic analysis was used to detect chemical treatment variations in SB and OMW samples, using techniques like milling, sieving, and pellet pressing, according to Singh et al.'s 2017 methodology. Extraction of trace elements and determination T he DTPA soil test was developed by Lindsay and Norvell ( 1978 ) to identify near-neutral soils with insufficient Mo, Ni, and Pb. The test involves extracting trace elements from amended and incubated soils using a solution of DTPA, TEA, and CaCl 2 , buffered to prevent sample pH effects. 3. Result 3.1 Effect of Activation on Modification of Biochar Properties Table 1 shows pH values of activated biochars, with nano sugar cane bagasse biochar and olive mill waste biochar showing higher values. KOH chemical modification significantly increases pH, while ZnCl 2 treatment majorly alters it. The highest pH values are observed in activated KOH sugar cane bagasse biochar. The study analyzed the effect of KOH and ZnCl 2 on the elemental content of nano sugar cane bagasse biochar and olive mill waste biochar, with values varying for C, H, O, N, Ca, Mg, and K, with no significant change in N content. Surface area is crucial for activated carbon quality, impacting pollutant removal. KOH and ZnCl 2 activation yields maximum surface area, followed by ZnCl 2 . Chemical analysis shows high carbon and oxygen contents in carbonized feedstock waste, with a graphite-like structure. Bulk biochar produced from both feedstocks shows low H/C and O/C ratios. Table (1) The physical- chemical analysis of activated bulk and nano biochar produced from different feedstock. Physico–chemical properties Feed Stock Nano SCB Nano OMW Control ZnCl 2 KOH Control ZnCl 2 KOH pH 8.96 c 9.45 b 9.77 a 9.75 c 9.88 a b 10.31 a EC µSm − 1 334 c 1114.6 b 986.8 a 1130 c 1136.22 b 1134.87 a Element content (%) C 75.93 c 74.39 b 75.58 a 75.67 c 74.67 b 75.67 a H 0.25 c 0.42 b 0.45 a 0.51 c 0.51 b 0.51 a O 20.28 bc 22.14 b 21.54 b 21.62 c 20.62 bc 20.62 a N 0.19 c 0.22 a 0.22 a 0.22 a 0.22 bc 0.22 a Ca 0.54 c 0.3 b 0.51 a 0.43 a 0.43 a 0.43 a Mg 0.32 b 0.35 b 0.22 a 0.26 a 0.26 a 0.26 a K 1.8 c 1.65 b 2.15 a 1.34 a 1.34 a 2.84 a Atomic ratios O/C 0.267 c 0.30 b 0.28 a 0.281 c 0.28 b 0.27 a H/C 0.003 c 0.01 bc 0.01 a 0.007 c 0.01 b 0.01 a (O + N)/C 0.270 c 0.30 b 0.29 a 0.283 c 0.28 b 0.28 a CEC 0.0025 c 35.4 b 35.6 a 0.0029 bc 32.5 ab 32.66 a SSA m 2 g − 1 35.64 c 511.5 ab 716.4 a 32.15 c 329.3 ab 424.5 a "a," "ab," "bc," and "c" According to the information above, the mean (or average) of the first variable, "a," differs statistically from the means of the third and fourth variables, "bc" and "c." However, there is no statistical difference between the first variable, "a," and the second, "ab." 3.2 Effect of Activation on Biochar Morphological Properties Scanning Electron Microscopy (SEM) explored the surface morphology of various biochar samples Figure (3: a, b, c, d, e and f). it examined the surface morphology of biochar samples, revealing irregular, oval-shaped pores with fractured edges. These images offer insights into the porosity of the char particles formed during the biomass carbonization process. Sugarcane bagasse biochar exhibits a highly porous structure, whereas olive mill waste biochar exhibits a less porous structure. This difference may be attributed to the lower volatile matter content in the olive mill waste biochar samples signifying more devolatilization during the pyrolysis process. SEM images of the nanomaterials synthesized from SCB and OMW reveal catalyst meshes in the background and arrays of cylindrical nanomaterials covering the surface. These nano cylinders have lengths on the order of 105 nm. Experiments conducted at pyrolysis temperatures of 550°C resulted in a smaller population of nanomaterials. Higher magnification images Figure (3: a, b, c, d, e and f) demonstrate that the nanomaterials appear as long fibers. KOH modification led to tubular and rod-like structures, increased pore abundance, and fragments. The thermal decomposition of KOH formed mineral components, while ZnCl 2 modification resulted in tubular and rod-like structures, increased pore abundance, and a significant increase in Zn content in EDS images. 3.3 Transmission Electron Microscopy (TEM) was employed to delve into the surface characteristics of biochar derived from sugarcane bagasse and olive mill waste, activated with KOH and ZnCl 2 , in nano-particle forms Figure (4: a, b, c, d, e and f). These images showcase various mesoporous structures linked to pyrolysis temperatures. sugarcane bagasse activated with KOH, (c) Nanobiochar from sugarcane bagasse activated with ZnCl 2 (d) Nano biochar from olive mill waste (e) Nano biochar from olive mill waste activated with KOH (f) Nano biochar from olive mill waste activated with ZnCl 2 The distribution of these structures transitions from ordered to disordered as the process proceeds. While the mesoporous structure appears less pronounced, sugarcane bagasse biochar exhibits a road-like appearance (Fig. 4 a), whereas olive mill waste biochar presents spherical structures (Fig. 4 d). TEM images reveal that the produced materials have a tubular form characteristic of carbon nanotubes (CNTs). They consist of coaxial tubular graphene sheets with lengths on the order of micrometers and diameters on the order of nanometers. Natural nanoparticles (NPs) possess high sorption capacity for both organic and inorganic contaminants and play a crucial role as geological catalysts due to their extensive surface area. Sugarcane bagasse biochar nano-particles have ordered structures, while olive mill waste biochar displays localized crystalline graphitic-type structures. Activation methods like KOH and ZnCl 2 yield high surface area. Figure (6) The FTIR spectrum of the olive mill waste nano biochar activated with control, KOH and ZnCl 2 . As Figure (5, 6) illustrates, Fourier transform infrared (FTIR) spectroscopy is used to characterize a compound's chemical structure by detecting rotation and vibration of molecules. It indicates vibrations of − OH, olefin compound synthesis, and phenolic O-H band. ZnCl 2 -modified biochar shows increased peak strength, suggesting it enhances surface functional group intensity. 3.4 The effect of biocharbased materials on the availability of trace elements "TE" in soil Results assure that the application of biochar at different rates and different activation (NA: not activation as a control treatment, KOH and ZnCl 2 activation) affects the available content of TE elements and heavy metals such as Ni, Pb, and Mo as cleared in Figure (7, 8 and 9). High addition rates to soil decrease of Pb, Ni, and Mo concentrations. Olive mill waste biochar decreased concentrations but not as sugarcane bagasse biochar. Inorganic elements do not degrade, unlike organic contaminants that may survive in biochar by sheltering them from microbial degradation. This suggests that inorganic elements do not degrade. By dividing the standard deviation by the square root of the number of measurements that comprise the mean (typically denoted by N), one can get the standard error. As the number of measurements (N) increases, the standard error decreases by dividing the standard deviation by the square root of N. This indicates how much greater confidence we have in the mean value. 4. Discussion The study indicates that nano biochar, with high moisture content, may impact its stability and storage characteristics in both SCB and OMW feedstocks ( Çakman et al., 2021 ). SCB samples have higher cellulose and hemicellulose content, resulting in higher volatile matter and fixed carbon in biochar, while OMW samples have more lignin and extractives, leading to higher ash content ( Torgbo et al., 2021 ).The study compares nano and bulk biochar properties from different feedstocks, revealing variations in structure, moisture content, organic matter, and solid carbon, impacting stability, storage, nutrient content, and pH value ( Çakman et al., 2021 ).These findings align with previous research which also reported higher moisture content, volatile matter, ash content, and fixed carbon percentages in nano biochar compared to bulk biochar from various feedstocks. Notably, nano biochar demonstrates a higher EC than bulk biochar for both feedstocks, indicating that nano biochar possesses a greater surface area and porosity, facilitating the dissolution and release of ions ( Tu et al., 2022 ). Olive mill waste biochar has higher EC values than sugarcane bagasse biochar due to its higher ash and mineral content ( Singh et al., 2022 ). Nano biochar has higher carbon content than bulk biochar due to aromatic structures and less volatile matter, while sugarcane bagasse biochar has higher carbon content due to lignin and cellulose. Nano biochar has lower O content ( Tu et al., 2022 ). The low CEC values of all biochars are primarily due to the decrease in surface functional groups like carboxyl, phenolic, and hydroxyl groups with higher pyrolysis temperatures ( Tomczyk et al., 2020 ), nano biochar demonstrates a slightly higher CEC than bulk biochar for both feedstocks, indicating its increased surface area and porosity for cation retention. OMW biochar exhibits a slightly lower CEC than SB biochar, largely due to the former's lower organic matter content ( Singh et al., 2022 ). This high SSA results from biochar's porosity, which is known to increase with higher pyrolysis temperatures ( Tomczyk et al., 2020 ). Nano biochar exhibits a slightly higher SSA than bulk biochar for both feedstocks, indicating its enhanced surface area and porosity for molecule adsorption ( Tu et al., 2022 ). Sugarcane bagasse biochar possesses a significantly higher SSA than olive mill waste biochar, mainly due to the former's higher lignin and cellulose content ( Tomczyk et al., 2020 ). Nano biochar has superior physical, chemical, and structural properties compared to bulk biochar, including larger surface area, increased functional groups, enhanced mechanical and thermal stability, and negative zeta potentials. Its carbon defects facilitate electron transfer and catalytic activity, making it suitable for various applications ( Chen et al., 2023 ). Recent studies show biochar is physically degraded into nanoscale particles, with a wide size range and 1.6–2.6% percentage in pristine pyrolyzed biochar. ( Chen et al., 2023 ). Nano-biochar, unlike bulk biochar, can migrate from terrestrial to aquatic environments, potentially stimulating antibiotic-resistant genes' decomposition and transformation inhibition, emphasizing the importance of size effects in biochar reactivity and environmental implications. ( Lian et al., 2020 ). Biochar-NPs, composed of carbon, have unique properties compared to naturally occurring soil nanoparticles, potentially influencing soil component aggregation and environmental contaminants distribution, potentially transporting them to plants and aquatic organisms ( Bakshi et al., 2015 ). This study analyzes the morphological and structural characteristics of biochar, particularly its nano form, to understand its environmental behavior and interaction with natural contaminants. ( Moradi-Choghamarani et al., 2019 ). The study aimed to identify functional groups on biochar surfaces, providing insights into pyrolysis process completeness and surface polarity. FTIR spectra showed vibration modes associated with aliphatic C-H, aromatic C = C, carboxylic C = O, and hydroxyl O-H, which determine biochar's properties like surface area, porosity, acidity, and adsorption capacity. The wave number 1600 cm − 1 indicates carboxylic groups in OMW, which are more abundant due to phenolic compounds. The peak intensity increases after nanotechnology treatment. The wave number 1400 cm − 1 corresponds to ether groups, also prevalent in OMW. The wave number 1100 cm − 1 indicates glycosidic linkages, which decrease after nanotechnology treatment ( Singh et al., 2022 ). Nanotechnology treatment can modify FTIR spectra by modifying the chemical composition and structure of SCB and OMW, enhancing hydrolysis of cellulose and hemicellulose, and altering phenolic compounds in OMW. Manure-based biochar has a distinct surface morphology, with irregularly shaped particles and salt coatings, potentially offering fertility benefits due to the attraction of ions from dissolved salts. ( Tu et al., 2022 ). SEM images of activated biochars show a honeycomb-like structure, with porous walls and monolithic structures. This structure provides strength, chemical resilience, and electrical conductivity. The activation process, involving ZnCl 2 , encourages etching, pore creation, and surface area increase. The presence of aromatic rings and inorganic metals is evident in the bands. The study reveals that biochar, unlike other biochar or activated carbons, shows less intensity in the 3500 − 2500 cm − 1 range due to the stability of surface functional groups under high-temperature activation, with peaks at 1616 cm − 1 , 1384 cm − 1 , 893–782 cm − 1 , and 2400–2000 cm − 1 . FTIR analysis of activated olive mill waste with zinc chloride reveals intense transmittance peaks and new functional groups on nano surfaces, enhancing hydrophilic properties and increasing oxidized compound dispersibility. However, activation and carbonization processes can lose spectral features. The activation process results in the removal of oxygen functionalities from activated carbons, resulting in the formation of a fused-ring structure. This is due to the loss of various functional groups, such as hydroxyl and aliphatic groups, from the surface of activated carbons ( Halbus et al., 2020 ). Trace Elements TE(s) detoxification in availability may be owing to TE(s) immobilization in the soil (see also Table 6). Because of its carbonaceous qualities, the sorption of TE(s) on biochar surfaces is part of the rhizosphere's removal of soil pollutants, reducing TE(s) availability to plants ( Zhou et al. 2015 ). Rees et al. (2014) found that applying BC (80% coniferous and 20% hardwood chips, 450°C) increased TE(s) immobilization in the soil and adsorption of TE(s) unique to BC mineral phases. Organic and mineral components found in BC may play a key role in TE(s) adsorption ( Xu and Chen 2015 ) . According to Xu and Chen ( 2015 ) , the water-soluble part of BC adsorbed Ni significantly more than the HCl-soluble ashes and insoluble silicon oxide solids. Biochar treatment (maple wood at 450°C) immobilized TE(s), Cu, Zn, and Pb in sandy loam urban soil. Similarly, biochar generated from gigantic Miscanthus lowered the mean cumulative Zn and Cd fluxes, which might be attributed to both lower TE(s) concentrations in the soil solution and decreased drainage ( Kargar et al. 2015 ). Mendez et al. ( 2014 ) found that applying paper sludge biochar (made at 500°C) to soil and incubating it for 77 days reduced the amount of leached and accessible Ni. Puga et al. ( 2015a ) found that applying biochar (sugarcane straw at 700°C) reduced DTPA extractable Zn, Pb, and Cd from the soil as well as the concentrations of these TE(s) in the pore water. Similarly, Al-Wabel et al. (2015) found that BC (Concarpus waste, 400°C) significantly reduced AB-DTPA-extractable TE(s) (Mn, Zn, Cd, Cu, and Pb) in soil. 5. Conclusion This research elucidates KOH's chemical activation mechanism during biomass pyrolysis, offering novel insights into the potential chemical reaction pathways between KOH and oxygen-containing groups. During the biomass pyrolysis process, KOH engages with active oxygen-containing species within the biomass, removing a substantial portion of oxygen-containing groups and forming numerous vacancies. In addition, this study extends the scope of activation techniques to include ZnCl 2 chemical activation, resulting in activated carbon samples with notably increased specific surface areas compared to the raw biochar material. However, it is worth noting that the specific surface area achieved with ZnC l2 activation does not reach the levels attained with KOH. In light of these findings, sugarcane bagasse emerges as a more promising raw material for biochar production when compared to olive mill waste, potentially opening avenues for more effective and sustainable biochar applications. Abbreviations CEC Cation Exchange Capacity CNT S Carbon Nanotubes EC Electrical Conductivity FTIR Fourier-transform infrared spectroscopy NP S Natural nanoparticles OMW Olive Mill Waste ROS Reactive Oxygen species SCB Sugar cane bagasse SEM Scanning electron microscopy TEM Transmission electron microscopy TE S Trace Elements Declarations ACKNOWLEDGEMENT We highly appreciate the support and cooperation of the Central Laboratory of the Agriculture Faculty at Menofia University, Egypt, for their invaluable assistance during the measurements for this work. Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. ETHICS The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Duality of interest: The authors declare that they have no conflict of interest in the publication. Author contributions: Authors Nehal.A.Ali and Basma.M.Ahmed write the original draft and substantial contribution to analysis and interpretation of data S.A.Radwan, E.A.Abou Hussien edit and finalize the manuscript. All authors read and agree for submission of manuscript to the journal. Funding: No specific funding was received for this work References Aissaoui, M. H., Trabelsi, A. B. H., Abidi, S., Zaafouri, K., Haddad, K., Jamaaoui, F., Leahy, J. J., & Kwapinski, W. (2021). 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Kargar M, Clark OG, Hendershot WH, Jutras P, Prasher SO (2015) Immobilization of trace metals in contaminated urban soil amended with compost and biochar. Water Air Soil Pollut 226:191 Lehmann, J., & Joseph, S. (Eds.). (2015). Biochar for environmental management: science, technology and implementation . Routledge.‏ Lian, F., Yu, W., Zhou, Q., Gu, S., Wang, Z., & Xing, B. (2020). Size matters: nano-biochar triggers decomposition and transformation inhibition of antibiotic resistance genes in aqueous environments. Environmental Science & Technology , 54 (14), 8821–8829. Lindsay, W. L., & Norvell, Wa. (1978). Development of a DTPA soil test for zinc, iron, manganese, and copper. Soil Science Society of America Journal , 42 (3), 421–428. McLaughlin, H., Shields, F., Jagiello, J., & Thiele, G. (2012). Analytical options for biochar adsorption and surface area. North American Biochar Conference, Sonoma, CA . Mendez A, Paz-Ferreiro J, Araujo F, Gasco G (2014) Biochar from pyrolysis of deinking paper sludge and its use in the treatment of a nickel polluted soil. J Anal Appl Pyrolysis 107:46–52 Mohamed, M. G., EL-Mahdy, A. F., Kotp, M. G., & Kuo, S. W. (2022). Advances in porous organic polymers: Syntheses, structures, and diverse applications. Materials Advances , 3 (2), 707-733.‏ Moradi-Choghamarani, F., Moosavi, A. A., & Baghernejad, M. (2019). Determining organo-chemical composition of sugarcane bagasse-derived biochar as a function of pyrolysis temperature using proximate and Fourier transform infrared analyses. Journal of Thermal Analysis and Calorimetry , 138 (1), 331–342. https://doi.org/10.1007/s10973-019-08186-9 Puga AP, Abreu CA, Melo LCA, Beesley L (2015a) Biochar application to a contaminated soil reduces the availability and plant uptake of zinc, lead and cadmium. J Environ Manag 159:86–93 Rees s F, Simonnot MO, Morel JL (2014) Short-term effects of biochar on soil heavy metal mobility are controlled by intra‐particle diffusion and soil pH increase. Eur J Soil Sci 65:149–161 Shaaban, S., & Nasr, M. (2018). Agricultural Wastes-To-Green Energy in Egypt. Biotech. Microbiol , 8 , 555750. Shafiq, F., Anwar, S., Zhang, L., & Ashraf, M. (2023). Nano‐biochar: Properties and prospects for sustainable agriculture. Land Degradation & Development . Singh, B., Camps-Arbestain, M., & Lehmann, J. (2017). Biochar: a guide to analytical methods . Csiro Publishing. Singh, H., Northup, B. K., Rice, C. W., & Prasad, P. V. V. (2022). Biochar applications influence soil physical and chemical properties, microbial diversity, and crop productivity: a meta-analysis. Biochar , 4 (1), 1–17. https://doi.org/10.1007/s42773-022-00138-1 Tan, X., Liu, S., Liu, Y., Gu, Y., Zeng, G., Hu, X., Wang, X., Liu, S., & Jiang, L. (2017). Biochar as potential sustainable precursors for activated carbon production: Multiple applications in environmental protection and energy storage. Bioresource Technology , 227 , 359–372. Tomczyk, A., Sokołowska, Z., & Boguta, P. (2020). Biochar physicochemical properties: pyrolysis temperature and feedstock kind effects. Reviews in Environmental Science and Bio/Technology , 19 (1), 191-215.‏ Torgbo, S., Quan, V. M., & Sukyai, P. (2021). Cellulosic value-added products from sugarcane bagasse. Cellulose , 28 (9), 5219–5240. Tu, P., Zhang, G., Wei, G., Li, J., Li, Y., Deng, L., & Yuan, H. (2022). Influence of pyrolysis temperature on the physicochemical properties of biochars obtained from herbaceous and woody plants. Bioresources and Bioprocessing , 9 (1). https://doi.org/10.1186/s40643-022-00618-z Uemura1a, Y., Afif1b, H., Osman1c, N., & Riaz1d, N. (2012). CHEMICAL ACTIVATION OF BIOCHAR MADE FROM OIL PALM KERNEL SHELL AND ITS APPLICATION TO ADSORBENT FOR P-NITROPHENOL. Energy , 91 , 954–959. Wallace, C. A., Afzal, M. T., & Saha, G. C. (2019). Effect of feedstock and microwave pyrolysis temperature on physio-chemical and nano-scale mechanical properties of biochar. Bioresources and Bioprocessing, 6(1), 1-11.‏ Wongrod, S. (2020). Biochars from solid digestates as sorbing materials for metal ( loid ) s removal from water Suchanya Wongrod To cite this version : HAL Id : tel-02474462 Tesi di Dottorato – Thèse – PhD thesis – Väitöskirja Suchanya Wongrod Biochars from solid digestates . Xu Y, Chen B (2015) Organic carbon and inorganic silicon speciation in rice-bran-derived biochars affect its capacity to adsorb cadmium in solution. J Soils Sediments 15:60–70 Zheng, S., Fan, J., Yu, F., Feng, B., Lou, B., Zou, Q., ... & Liang, T. (2020). Viral load dynamics and disease severity in patients infected with SARS-CoV-2 in Zhejiang province, China, January-March 2020: retrospective cohort study. bmj, 369.‏ Zhou F, Wang H, Zhang W, Qiu R (2015) Pb (II), Cr (VI) and atrazine sorption behavior on sludge-derived biochar: role of humic acids. Environ Sci Pollut Res doi:10.1007/s11356-015-4818-7 Additional Declarations No competing interests reported. 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. 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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-4430795","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":308139082,"identity":"debf6ca6-a695-49e0-b708-83287632e923","order_by":0,"name":"Salah Radwan","email":"","orcid":"","institution":"Menoufia University","correspondingAuthor":false,"prefix":"","firstName":"Salah","middleName":"","lastName":"Radwan","suffix":""},{"id":308139083,"identity":"95f26065-4389-4437-b03b-e0e458754a8a","order_by":1,"name":"El-Husieny Abou Hussien","email":"","orcid":"","institution":"Menoufia University","correspondingAuthor":false,"prefix":"","firstName":"El-Husieny","middleName":"Abou","lastName":"Hussien","suffix":""},{"id":308139084,"identity":"ba926905-5e76-487a-9889-a7621153309d","order_by":2,"name":"Basma Ahmed","email":"data:image/png;base64,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","orcid":"","institution":"Menoufia University","correspondingAuthor":true,"prefix":"","firstName":"Basma","middleName":"","lastName":"Ahmed","suffix":""},{"id":308139085,"identity":"5eee4df3-25fd-47ee-a1b1-2624ddd64e50","order_by":3,"name":"Nehal Ali","email":"","orcid":"","institution":"Tanta University","correspondingAuthor":false,"prefix":"","firstName":"Nehal","middleName":"","lastName":"Ali","suffix":""}],"badges":[],"createdAt":"2024-05-16 11:32:58","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4430795/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4430795/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":57636826,"identity":"af5d1b4c-de42-46cb-a89e-4af9264b4914","added_by":"auto","created_at":"2024-06-03 16:09:18","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":48494,"visible":true,"origin":"","legend":"\u003cp\u003eThe processes which agricultural waste (sugarcane bagasse and olive mill waste) went through to reach activated biochar\u003c/p\u003e","description":"","filename":"Picture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4430795/v1/e9f7ac4987c8ab9aebd1429b.jpg"},{"id":57635918,"identity":"4ba678dc-3fea-4eb3-9a26-cc10365250f1","added_by":"auto","created_at":"2024-06-03 16:01:18","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":30318,"visible":true,"origin":"","legend":"\u003cp\u003eMethodology of the experimental study\u003c/p\u003e","description":"","filename":"Picture2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4430795/v1/587aea8b958f551c15681053.jpg"},{"id":57635922,"identity":"4f02c058-0fc5-45fb-9b3a-6c0dd0e1fc99","added_by":"auto","created_at":"2024-06-03 16:01:18","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":176260,"visible":true,"origin":"","legend":"\u003cp\u003eSEM micrograph of (a) Nanobiochar from sugarcane bagasse (b) Nanobiochar from sugarcane bagasse activated with KOH, (c) Nanobiochar from sugarcane bagasse activated with ZnCl\u003csub\u003e2\u003c/sub\u003e (d) Nano biochar from olive mill waste (e) Nano biochar from olive mill waste activated with KOH (d) Nano biochar from olive mill waste activated with ZnCl\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"Picture3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4430795/v1/3d4a638793bb7cfbf53d9520.jpg"},{"id":57635925,"identity":"c65984f6-e4c8-47ec-85ec-585b7d1035b1","added_by":"auto","created_at":"2024-06-03 16:01:18","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":173769,"visible":true,"origin":"","legend":"\u003cp\u003eTEM images of\u0026nbsp; (a) Nanobiochar from sugarcane bagasse (b) Nanobiochar from\u003c/p\u003e\n\u003cp\u003esugarcane bagasse activated with KOH, (c) Nanobiochar from sugarcane bagasse activated with ZnCl\u003csub\u003e2\u003c/sub\u003e (d) Nano biochar from olive mill waste (e) Nano biochar from olive mill waste activated with KOH (f) Nano biochar from olive mill waste activated with ZnCl\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"Picture4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4430795/v1/834cf1ed9e242c54809a23a4.jpg"},{"id":57635919,"identity":"5d28bf74-d6f0-4c70-8668-552ae2150ef3","added_by":"auto","created_at":"2024-06-03 16:01:18","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":119107,"visible":true,"origin":"","legend":"\u003cp\u003eThe FTIR spectrum of the sugar cane bagasse nano biochar activated with control, KOH and ZnCl\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e","description":"","filename":"Picture5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4430795/v1/ae67234ffbfe338b496843b5.jpg"},{"id":57635927,"identity":"1a5a1d3e-b91f-4735-87c2-cca3ec5bddfe","added_by":"auto","created_at":"2024-06-03 16:01:18","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":136369,"visible":true,"origin":"","legend":"\u003cp\u003eThe FTIR spectrum of the olive mill waste nano biochar activated with control, KOH and ZnCl\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e","description":"","filename":"Picture6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4430795/v1/f965ceed7691955166a9abbb.jpg"},{"id":57635924,"identity":"5838b09f-285e-44f7-a652-b4b3a5d6901c","added_by":"auto","created_at":"2024-06-03 16:01:18","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":113679,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of \u0026nbsp;activation of nano biochar on the availability of Pb in soil\u003c/p\u003e","description":"","filename":"Picture7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4430795/v1/22151d65162b769fb8285f43.jpg"},{"id":57637342,"identity":"d65927e5-2a3d-42ee-871d-d9b4395d20b7","added_by":"auto","created_at":"2024-06-03 16:17:18","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":106570,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of activation of nano biochar on the availability of Ni in soil\u003c/p\u003e","description":"","filename":"Picture8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4430795/v1/0dee8176421f5ea92355c3b6.jpg"},{"id":57636828,"identity":"21b5d152-dd00-4f56-8bb8-a28c7259f34c","added_by":"auto","created_at":"2024-06-03 16:09:19","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":119858,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of activation of nano biochar on the availability of Mo in soil\u003c/p\u003e","description":"","filename":"Picture9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4430795/v1/a9c2044af69558ebb670833c.jpg"},{"id":58017299,"identity":"729f2687-2ac6-490b-9909-4f1b646eefb1","added_by":"auto","created_at":"2024-06-10 03:53:39","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1833099,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4430795/v1/e866ece3-5bd9-4751-a84b-ac9e6a810547.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Green Solutions for Soil Contamination: Sustainable Production and Characterization of Nano-Biochar from Sugarcane Bagasse and Olive Mill Waste","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eSoil contamination due to herbicides, pesticides, antibiotics, and sewage-contaminated water poses a significant environmental threat. Sorption offers an efficient solution due to its adaptability, competitive performance, and simplicity. One of these primary consequences is soil contamination with trace elements (TEs), which is primarily caused by human activity. These activities include mining and the widespread use of industrial waste, sewage sludge, fertilizer, and pesticides, notably in agriculture. TEs comprise both biologically vital elements like zinc (Zn), cobalt (Co), copper (Cu), and manganese (Mn) and non-essential elements like cadmium (Cd), chromium (Cr), arsenic (As), and lead (Pb). Essential elements are necessary in trace amounts for proper plant and animal growth and development, and are thus referred to as micronutrients. However, in large quantities, these metals are toxic to living organisms \u003cb\u003e(\u003c/b\u003eMohamed et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Soil contamination with trace elements (TEs) is a major consequence of human activities like mining and industrial waste, particularly in agriculture. These toxic metals, produced annually in Egypt, pose resource optimization opportunities. \u003cb\u003e(\u003c/b\u003eShaaban and Nasr, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2018\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. Previous research has demonstrated that soil contaminated with lead (Pb), nickel (Ni), and molybdenum (Mo) among other metals. According to certain theories, excessive amounts of Pb, Ni, and Mo in these elements might affect vegetables and result in toxicological issues for adults and children.\u003c/p\u003e \u003cp\u003eHeavy metal soil remediation methods, including excavation, washing procedures, landfilling, and solidification of the soil, can be costly and labor-intensive. As an alternative to landfilling, excavation, and other forms of soil remediation, in situ methods like the immobilization of heavy metals may be less expensive and have a smaller negative ecological impact. Biological, physical, and chemical methods can be used to remediate polluted soils that contain immobilized heavy metals The main objective of immobilizing heavy metals by the addition of amendments to polluted soils is to decrease metal mobility and toxicity through metal sorption and precipitation, rather than to change the total metal content. In order to adsorb metals in soil and water, carbon-rich supplements like compost and biochar have recently been employed as innovative carbonaceous materials and commercially viable technologies \u003cb\u003e(Almaroai et al. 2014).\u003c/b\u003e\u003c/p\u003e \u003cp\u003eNanobiochar has found wide-ranging uses, such as a material for removing contaminants, a catalyst, a carrier of biomolecules, an electrode material, a sensing material, a substitute for carbon black, and a material for the battery sector. Moreover, rice and wheat may be grown more rapidly with the use of nanobiochar as a growing medium. The majority of studies on nanobiochar concentrate on its application as an adsorbent substance. It has been investigated how well nanobiochar removes a variety of materials, including as agrochemicals, medicines, potentially hazardous materials, and organic and inorganic molecules. One of the primary obstacles to commercializing the product is the extremely low yield of nanobiochar produced by the other methods, with the exception of ball-milling, which produces nanobiochar as a direct end product \u003cb\u003e(\u003c/b\u003eZheng et al., \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Furthermore, transferring from the lab to the industrial scale could result in a variety of problems throughout the milling process. Thus, more research on marketable nanobiochar is required, as well as a techno-economic study \u003cb\u003e(\u003c/b\u003eZheng et al., \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). When it came to the adsorption of organic molecules like carbamazepine, pinewood nanobiochar showed greater capabilities than carbonaceous materials like carbon nanotubes, activated carbon, and graphene oxides (95%). High surface area, graphitic composition, variably charged functional groups, and components like humic acid are the foundation of nanobiochar's adsorption potential. Examining hardwood nanobiochar's ability to eliminate both organic and inorganic micropollutants \u003cb\u003eRamanayaka et al. (2020)\u003c/b\u003e, who, as a result of the existence of various functional groups such \u0026ndash;OH, C\u0026thinsp;=\u0026thinsp;O, and \u0026ndash;NH, showed high removal capabilities of 83, 520, 922, and 7.46 mg g-1 for glyphosate, oxytetracycline, Cd(II), and Cr(VI), respectively. The main factors influencing the surface functional groups in nanobiochar are the temperature during pyrolysis and the kind of feedstock. The material's volatile organic chemicals may devolatilize as a result of the rising temperature, which will reduce the amount of surface functional groups. Nonetheless, research indicates that compared to unmilled virgin biochar (0.8\u0026ndash;2.9 mmol g\u0026ndash;1), ball-milled biochar has a higher concentration of oxygen-containing functional groups (2.2\u0026ndash;4.4 mmol g\u0026ndash;1) Cao et al. (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). In addition, following ball-milling, there are more acidic surface functional groups, which improves adsorption effectiveness. Additionally, milling reveals the graphitic character of the nanobiochar and causes the production of reactive oxygen species (ROS), which may enhance the surface chemistry of the biochar relative to its pristine state. The surface functional groups have been identified by most research using FTIR spectroscopy, and others have utilized Boehm titration to quantify those groups. Acidic functional group concentrations in bagasse biochar were shown to rise after milling, from 0.8 to 2.5 mmol g-1 \u003cb\u003e(\u003c/b\u003eWallace et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Such pollutants in water may be transported by nanobiochar. The high ROS content of nanobiochar may have an impact on the deterioration of organic materials like oxytetracycline and glyphosate. Nevertheless, there is a dearth of information regarding the adsorption process's organic pollutant degradation in the presence of ROS. Enhancing the adsorption capacity of biochar can also be achieved by modifying its mechanical, chemical, and physical properties. Pinewood nano biochar's adsorption capability can be increased by 57% by employing a surfactant to change the pH of the solution from acidic to basic. The adsorption performance of goethite-modified peanut shell nanobiochar was improved through the formation of intercalated hetero structures and hetero aggregation \u003cb\u003eRamanayaka et al. (2020)\u003c/b\u003e.\u003c/p\u003e \u003cp\u003eFurther modification of nano biochar chemical and physical properties can be achieved through process defined \u0026ldquo;activation\u0026rdquo;, aimed at increasing nano biochar porosity and modifying its pore size distribution, as well as to some extent surface chemistry \u003cb\u003e(\u003c/b\u003eShafiq et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Activation can be carried out in a number of ways, depending on type of activation agents (e.g. physical and chemical activation) or mode of operation into single-stage or multi-stage activation. Chemical activation utilizes chemical agents, e.g., H\u003csub\u003e3\u003c/sub\u003ePO\u003csub\u003e4\u003c/sub\u003e, HNO\u003csub\u003e3\u003c/sub\u003e, KOH, NaOH, H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e, and ZnCl\u003csub\u003e2\u003c/sub\u003e \u003cb\u003e(\u003c/b\u003eTan et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). It typically involves two steps; in the first the feedstock is impregnated with a selected chemical agent, and then thermally treated in the second step. Another option is the activation of already produced biochar by soaking it in a chemical agent, followed by a thermal treatment \u003cb\u003e(\u003c/b\u003eLehmann and Joseph, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2015\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. Depending on the agent selected and thermal treatment conditions used, different degrees of activation can be achieved. The activated nano biochar needs to be thoroughly washed with deionized water to neutralize its pH and to remove any remaining chemicals, and this procedure can contribute to a negative environmental impact of the technology. Oxidative activation that uses acidic or alkaline agents is among the most common activation methods. Besides enhancing porosity and surface area, it also creates oxygen-containing functional groups on the surface of biochar (e.g. carboxyl, hydroxyl, lactone, phenol, carbonyl, and peroxide groups) \u003cb\u003e(Wongrod et al., 2020)\u003c/b\u003e. The properties of biochar, including surface area, porosity, and functional groups, significantly influence its adsorption performance \u003cb\u003e(\u003c/b\u003eJang et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). These properties depend on factors like feedstock, pyrolysis conditions, and post-treatment modifications such as sulphonation, amination, oxidation, and metal nanoparticle impregnation \u003cb\u003e(\u003c/b\u003eTan et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Some studies have shown that salt chlorides like ZnCl\u003csub\u003e2\u003c/sub\u003e can enhance carbon porosity more effectively than certain acids and bases \u003cb\u003e(\u003c/b\u003eAteş and \u0026Ouml;zcan, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2018\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. Activators like ZnCl\u003csub\u003e2\u003c/sub\u003e have also been found to increase pore volume in the 2\u0026ndash;10 nm range. Additionally, FeCl\u003csub\u003e3\u003c/sub\u003e, as an activator, has improved biochar yield, granule strength, and adsorption capabilities. Nano biochar properties, including surface area, porosity, and functional groups, significantly influence adsorption performance, influenced by factors like feedstock, pyrolysis conditions, and post-treatment modifications. \u003cb\u003e(\u003c/b\u003eAteş and \u0026Ouml;zcan, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2018\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. This study aimed to produce nanobiochar from sugarcane bagasse (SCB) and olive mill waste (OMW) via pyrolysis, analyzing their composition, functional groups, and morphology. It explored KOH and ZnCl\u003csub\u003e2\u003c/sub\u003e chemical activation methods for the nanobiochar produced from both resources, revealing new understanding about their mechanisms and effectiveness in reducing environmental toxicity TE(s).\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Agricultural Waste\u003c/h2\u003e \u003cp\u003eThe biochar was made from sugarcane bagasse and olive mill waste, obtained from a Sadat City facility in Egypt. The waste was prepared by cutting, washing, and drying in an oven.\u003c/p\u003e \u003cp\u003e \u003cb\u003ePyrolysis Procedure\u003c/b\u003e \u003c/p\u003e \u003cp\u003eIn Soil Science Department at Menofia University conducted pyrolysis experiments on agricultural wastes using a stainless steel chamber heated with a muffle furnace. The biomass was subjected to temperatures ranging from 400˚C to 550˚C for 90 minutes under oxygen-free conditions.\u003c/p\u003e \u003cp\u003e \u003cb\u003eNano Biochar Fabrication through Milling\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe nano biochar was prepared using a ball-milling technique, grounding sugarcane bagasse and olive mill waste in 180g of agate balls at 350\u0026deg;C for 12 hours.\u003cb\u003e(\u003c/b\u003eAmusat et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Chemical Activation Procedures\u003c/h2\u003e \u003cp\u003e \u003cb\u003eActivation with KOH\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe biochar was chemically activated using \u003cb\u003eWongrod in 2020\u003c/b\u003e method, which involved adding 2 grams of biochar to a 250 ml conical flask, shaking for 2 hours, and then rinsing with deionized water, repeating the process 3\u0026ndash;4 times until the pH level stabilized.\u003c/p\u003e \u003cp\u003e \u003cb\u003eActivation with ZnCl2\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eUemura et al.'s 2012\u003c/b\u003e method for activating biochar involved soaking 10 grams of biochar in a 1 M ZnCl2 solution, drying it in an oven, stirring it in a 0.10 M HCl solution, washing it with hot deionized water, and drying it overnight at 110 ⁰C.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Experimental design\u003c/h2\u003e \u003cp\u003eThe experiment was set up in completely randomized design (CRD) consisting of twelve (12) treatment combinations SCBNK 0, SCBNK 0.4, SCBNK 0.6, SCBNK 0.8, SCBNZ 0, SCBNZ 0.4, SCBNZ 0.6, SCBNZ 0.8, OMWNK 0, OMWNK 0.4, OMWNK 0.6, OMWNK 0.8, OMWNZ 0, OMWNZ 0.4, OMWNZ 0.6, OMWNZ 0.8,where SCB indicates biochar from sugar cane bagasse, OMW indicates biochar from olive mill waste, N indicates nano size, K indicates to KOH activation, Z indicates to ZnCl\u003csub\u003e2\u003c/sub\u003e activation and 0, 0.4, 0.6 and 0.8% indicates to application rate.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Experimental procedures\u003c/h2\u003e \u003cp\u003eSoil was mixed with amendment at different rates, incubated for 40 days, and wetted with distilled water daily. The control soil remained unaffected.\u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.4.1 Ultimate and Proximate Analysis of Biochar and Residues\u003c/h2\u003e \u003cp\u003eThe analysis of biochar and residue samples involved determining C, N, and H percentage contents, assessing ash and volatile matter content, and observing weight loss post-combustion to provide insights into these components by \u003cb\u003e(\u003c/b\u003eMcLaughlin et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2012\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.4.2 Physico-Chemical Analysis of Biochar\u003c/h2\u003e \u003cp\u003e \u003cb\u003eBiochar Characteristics\u003c/b\u003e analysis of biochar involved determining pH, EC, and elemental composition, including carbon, oxygen, hydrogen, nitrogen, calcium, magnesium, and potassium (Singh et al.'s \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2017\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e.\u003c/p\u003e \u003cp\u003e \u003cb\u003eMicronutrients and Heavy Metals\u003c/b\u003e The biochar's micronutrients and heavy metals levels were assessed using a method by \u003cb\u003e(\u003c/b\u003eLindsay and Norvell, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1978\u003c/span\u003e) followed by atomic absorption spectrophotometry using the NovAA800\u0026reg;F model.\u003c/p\u003e \u003cp\u003e \u003cb\u003eMorphological and Crystal Properties\u003c/b\u003e Morphological examination of biochar using SEM imaging and TEM analysis after sonication in ethanol, using Hitachi TM-1000 device and two different TEM devices.\u003c/p\u003e \u003cp\u003e \u003cb\u003eSurface Chemistry\u003c/b\u003e FTIR spectroscopic analysis was used to detect chemical treatment variations in SB and OMW samples, using techniques like milling, sieving, and pellet pressing, according to Singh et al.'s \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2017\u003c/span\u003e methodology.\u003c/p\u003e \u003cp\u003e \u003cb\u003eExtraction of trace elements and determination T\u003c/b\u003ehe DTPA soil test was developed by Lindsay and Norvell (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1978\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e to identify near-neutral soils with insufficient Mo, Ni, and Pb. The test involves extracting trace elements from amended and incubated soils using a solution of DTPA, TEA, and CaCl\u003csub\u003e2\u003c/sub\u003e, buffered to prevent sample pH effects.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"3. Result","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Effect of Activation on Modification of Biochar Properties\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;1 shows pH values of activated biochars, with nano sugar cane bagasse biochar and olive mill waste biochar showing higher values. KOH chemical modification significantly increases pH, while ZnCl\u003csub\u003e2\u003c/sub\u003e treatment majorly alters it. The highest pH values are observed in activated KOH sugar cane bagasse biochar. The study analyzed the effect of KOH and ZnCl\u003csub\u003e2\u003c/sub\u003e on the elemental content of nano sugar cane bagasse biochar and olive mill waste biochar, with values varying for C, H, O, N, Ca, Mg, and K, with no significant change in N content.\u003c/p\u003e \u003cp\u003eSurface area is crucial for activated carbon quality, impacting pollutant removal. KOH and ZnCl\u003csub\u003e2\u003c/sub\u003e activation yields maximum surface area, followed by ZnCl\u003csub\u003e2\u003c/sub\u003e. Chemical analysis shows high carbon and oxygen contents in carbonized feedstock waste, with a graphite-like structure. Bulk biochar produced from both feedstocks shows low H/C and O/C ratios.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eTable\u0026nbsp;(1)\u003c/strong\u003e \u003cp\u003eThe physical- chemical analysis of activated bulk and nano biochar produced from\u003c/p\u003e \u003c/p\u003e \u003cp\u003edifferent feedstock.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"7\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003ePhysico\u0026ndash;chemical properties\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"6\" nameend=\"c7\" namest=\"c2\"\u003e \u003cp\u003eFeed Stock\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eNano SCB\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c7\" namest=\"c5\"\u003e \u003cp\u003eNano OMW\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eControl\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eZnCl\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eKOH\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eControl\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eZnCl\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eKOH\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003epH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.96 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.45 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.77 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9.75 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e9.88 \u003csup\u003ea b\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e10.31 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEC \u0026micro;Sm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e334 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1114.6 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e986.8 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1130 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1136.22 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1134.87 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eElement content (%)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e75.93 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e74.39 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e75.58 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e75.67 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e74.67 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e75.67 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.25 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.42 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.45 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.51 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.51 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.51 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20.28 \u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22.14 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e21.54 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e21.62 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e20.62 \u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e20.62 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.19 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.22 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.22 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.22 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.22 \u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.22 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.54 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.3 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.51 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.43 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.43 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.43 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.32 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.35 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.22 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.26 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.26 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.26 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eK\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.8 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.65 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.15 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.34 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.34 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.84 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAtomic ratios\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eO/C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.267 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.30 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.28 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.281 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.28 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.27\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eH/C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.003 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.01 \u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.01 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.007\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.01\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.01 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e(O\u0026thinsp;+\u0026thinsp;N)/C\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.270 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.30 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.29 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.283 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.28\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.28\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCEC\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.0025 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e35.4 \u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e35.6 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.0029 \u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e32.5\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e32.66 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSSA m\u003c/b\u003e\u003csup\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eg\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;1\u003c/b\u003e\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e35.64 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e511.5 \u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e716.4 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e32.15 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e329.3\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e424.5\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003e\"a,\" \"ab,\" \"bc,\" and \"c\"\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAccording to the information above, the mean (or average) of the first variable, \"a,\" differs statistically from the means of the third and fourth variables, \"bc\" and \"c.\" However, there is no statistical difference between the first variable, \"a,\" and the second, \"ab.\"\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Effect of Activation on Biochar Morphological Properties\u003c/h2\u003e \u003cp\u003eScanning Electron Microscopy (SEM) explored the surface morphology of various biochar samples Figure (3: a, b, c, d, e and f). it examined the surface morphology of biochar samples, revealing irregular, oval-shaped pores with fractured edges. These images offer insights into the porosity of the char particles formed during the biomass carbonization process. Sugarcane bagasse biochar exhibits a highly porous structure, whereas olive mill waste biochar exhibits a less porous structure. This difference may be attributed to the lower volatile matter content in the olive mill waste biochar samples signifying more devolatilization during the pyrolysis process.\u003c/p\u003e \u003cp\u003eSEM images of the nanomaterials synthesized from SCB and OMW reveal catalyst meshes in the background and arrays of cylindrical nanomaterials covering the surface. These nano cylinders have lengths on the order of 105 nm. Experiments conducted at pyrolysis temperatures of 550\u0026deg;C resulted in a smaller population of nanomaterials. Higher magnification images Figure (3: a, b, c, d, e and f) demonstrate that the nanomaterials appear as long fibers.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eKOH modification led to tubular and rod-like structures, increased pore abundance, and fragments. The thermal decomposition of KOH formed mineral components, while ZnCl\u003csub\u003e2\u003c/sub\u003e modification resulted in tubular and rod-like structures, increased pore abundance, and a significant increase in Zn content in EDS images.\u003c/p\u003e \u003cp\u003e \u003cb\u003e3.3 Transmission Electron Microscopy (TEM)\u003c/b\u003e was employed to delve into the surface characteristics of biochar derived from sugarcane bagasse and olive mill waste, activated with KOH and ZnCl\u003csub\u003e2\u003c/sub\u003e, in nano-particle forms Figure (4: a, b, c, d, e and f). These images showcase various mesoporous structures linked to pyrolysis temperatures.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003esugarcane bagasse activated with KOH, (c) Nanobiochar from sugarcane bagasse activated with ZnCl\u003csub\u003e2\u003c/sub\u003e (d) Nano biochar from olive mill waste (e) Nano biochar from olive mill waste activated with KOH (f) Nano biochar from olive mill waste activated with ZnCl\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eThe distribution of these structures transitions from ordered to disordered as the process proceeds. While the mesoporous structure appears less pronounced, sugarcane bagasse biochar exhibits a road-like appearance (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea), whereas olive mill waste biochar presents spherical structures (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ed). TEM images reveal that the produced materials have a tubular form characteristic of carbon nanotubes (CNTs). They consist of coaxial tubular graphene sheets with lengths on the order of micrometers and diameters on the order of nanometers. Natural nanoparticles (NPs) possess high sorption capacity for both organic and inorganic contaminants and play a crucial role as geological catalysts due to their extensive surface area. Sugarcane bagasse biochar nano-particles have ordered structures, while olive mill waste biochar displays localized crystalline graphitic-type structures. Activation methods like KOH and ZnCl\u003csub\u003e2\u003c/sub\u003e yield high surface area.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eFigure\u0026nbsp;(6)\u003c/b\u003e The FTIR spectrum of the olive mill waste nano biochar activated with control, KOH and ZnCl\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e \u003cp\u003eAs Figure (5, 6) illustrates, Fourier transform infrared (FTIR) spectroscopy is used to characterize a compound's chemical structure by detecting rotation and vibration of molecules. It indicates vibrations of \u0026minus;\u0026thinsp;OH, olefin compound synthesis, and phenolic O-H band. ZnCl\u003csub\u003e2\u003c/sub\u003e-modified biochar shows increased peak strength, suggesting it enhances surface functional group intensity.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.4 The effect of biocharbased materials on the availability of trace elements \"TE\" in soil\u003c/h2\u003e \u003cp\u003eResults assure that the application of biochar at different rates and different activation (NA: not activation as a control treatment, KOH and ZnCl\u003csub\u003e2\u003c/sub\u003e activation) affects the available content of TE elements and heavy metals such as Ni, Pb, and Mo as cleared in Figure (7, 8 and 9). High addition rates to soil decrease of Pb, Ni, and Mo concentrations. Olive mill waste biochar decreased concentrations but not as sugarcane bagasse biochar. Inorganic elements do not degrade, unlike organic contaminants that may survive in biochar by sheltering them from microbial degradation. This suggests that inorganic elements do not degrade. By dividing the standard deviation by the square root of the number of measurements that comprise the mean (typically denoted by N), one can get the standard error. As the number of measurements (N) increases, the standard error decreases by dividing the standard deviation by the square root of N. This indicates how much greater confidence we have in the mean value.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe study indicates that nano biochar, with high moisture content, may impact its stability and storage characteristics in both SCB and OMW feedstocks \u003cb\u003e(\u003c/b\u003e\u0026Ccedil;akman et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). SCB samples have higher cellulose and hemicellulose content, resulting in higher volatile matter and fixed carbon in biochar, while OMW samples have more lignin and extractives, leading to higher ash content \u003cb\u003e(\u003c/b\u003eTorgbo et al., \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).The study compares nano and bulk biochar properties from different feedstocks, revealing variations in structure, moisture content, organic matter, and solid carbon, impacting stability, storage, nutrient content, and pH value \u003cb\u003e(\u003c/b\u003e\u0026Ccedil;akman et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).These findings align with previous research which also reported higher moisture content, volatile matter, ash content, and fixed carbon percentages in nano biochar compared to bulk biochar from various feedstocks. Notably, nano biochar demonstrates a higher EC than bulk biochar for both feedstocks, indicating that nano biochar possesses a greater surface area and porosity, facilitating the dissolution and release of ions \u003cb\u003e(\u003c/b\u003eTu et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Olive mill waste biochar has higher EC values than sugarcane bagasse biochar due to its higher ash and mineral content \u003cb\u003e(\u003c/b\u003eSingh et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Nano biochar has higher carbon content than bulk biochar due to aromatic structures and less volatile matter, while sugarcane bagasse biochar has higher carbon content due to lignin and cellulose. Nano biochar has lower O content \u003cb\u003e(\u003c/b\u003eTu et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The low CEC values of all biochars are primarily due to the decrease in surface functional groups like carboxyl, phenolic, and hydroxyl groups with higher pyrolysis temperatures \u003cb\u003e(\u003c/b\u003eTomczyk et al., \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), nano biochar demonstrates a slightly higher CEC than bulk biochar for both feedstocks, indicating its increased surface area and porosity for cation retention. OMW biochar exhibits a slightly lower CEC than SB biochar, largely due to the former's lower organic matter content \u003cb\u003e(\u003c/b\u003eSingh et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). This high SSA results from biochar's porosity, which is known to increase with higher pyrolysis temperatures \u003cb\u003e(\u003c/b\u003eTomczyk et al., \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Nano biochar exhibits a slightly higher SSA than bulk biochar for both feedstocks, indicating its enhanced surface area and porosity for molecule adsorption \u003cb\u003e(\u003c/b\u003eTu et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Sugarcane bagasse biochar possesses a significantly higher SSA than olive mill waste biochar, mainly due to the former's higher lignin and cellulose content \u003cb\u003e(\u003c/b\u003eTomczyk et al., \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Nano biochar has superior physical, chemical, and structural properties compared to bulk biochar, including larger surface area, increased functional groups, enhanced mechanical and thermal stability, and negative zeta potentials. Its carbon defects facilitate electron transfer and catalytic activity, making it suitable for various applications \u003cb\u003e(\u003c/b\u003eChen et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Recent studies show biochar is physically degraded into nanoscale particles, with a wide size range and 1.6\u0026ndash;2.6% percentage in pristine pyrolyzed biochar. \u003cb\u003e(\u003c/b\u003eChen et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eNano-biochar, unlike bulk biochar, can migrate from terrestrial to aquatic environments, potentially stimulating antibiotic-resistant genes' decomposition and transformation inhibition, emphasizing the importance of size effects in biochar reactivity and environmental implications.\u003cb\u003e(\u003c/b\u003eLian et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Biochar-NPs, composed of carbon, have unique properties compared to naturally occurring soil nanoparticles, potentially influencing soil component aggregation and environmental contaminants distribution, potentially transporting them to plants and aquatic organisms \u003cb\u003e(\u003c/b\u003eBakshi et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). This study analyzes the morphological and structural characteristics of biochar, particularly its nano form, to understand its environmental behavior and interaction with natural contaminants.\u003cb\u003e(\u003c/b\u003eMoradi-Choghamarani et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). The study aimed to identify functional groups on biochar surfaces, providing insights into pyrolysis process completeness and surface polarity. FTIR spectra showed vibration modes associated with aliphatic C-H, aromatic C\u0026thinsp;=\u0026thinsp;C, carboxylic C\u0026thinsp;=\u0026thinsp;O, and hydroxyl O-H, which determine biochar's properties like surface area, porosity, acidity, and adsorption capacity. The wave number 1600 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e indicates carboxylic groups in OMW, which are more abundant due to phenolic compounds. The peak intensity increases after nanotechnology treatment. The wave number 1400 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e corresponds to ether groups, also prevalent in OMW. The wave number 1100 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e indicates glycosidic linkages, which decrease after nanotechnology treatment \u003cb\u003e(\u003c/b\u003eSingh et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Nanotechnology treatment can modify FTIR spectra by modifying the chemical composition and structure of SCB and OMW, enhancing hydrolysis of cellulose and hemicellulose, and altering phenolic compounds in OMW. Manure-based biochar has a distinct surface morphology, with irregularly shaped particles and salt coatings, potentially offering fertility benefits due to the attraction of ions from dissolved salts.\u003cb\u003e(\u003c/b\u003eTu et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSEM images of activated biochars show a honeycomb-like structure, with porous walls and monolithic structures. This structure provides strength, chemical resilience, and electrical conductivity. The activation process, involving ZnCl\u003csub\u003e2\u003c/sub\u003e, encourages etching, pore creation, and surface area increase. The presence of aromatic rings and inorganic metals is evident in the bands. The study reveals that biochar, unlike other biochar or activated carbons, shows less intensity in the 3500\u0026thinsp;\u0026minus;\u0026thinsp;2500 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e range due to the stability of surface functional groups under high-temperature activation, with peaks at 1616 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 1384 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, 893\u0026ndash;782 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, and 2400\u0026ndash;2000 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. FTIR analysis of activated olive mill waste with zinc chloride reveals intense transmittance peaks and new functional groups on nano surfaces, enhancing hydrophilic properties and increasing oxidized compound dispersibility. However, activation and carbonization processes can lose spectral features. The activation process results in the removal of oxygen functionalities from activated carbons, resulting in the formation of a fused-ring structure. This is due to the loss of various functional groups, such as hydroxyl and aliphatic groups, from the surface of activated carbons \u003cb\u003e(\u003c/b\u003eHalbus et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTrace Elements TE(s) detoxification in availability may be owing to TE(s) immobilization in the soil (see also Table\u0026nbsp;6). Because of its carbonaceous qualities, the sorption of TE(s) on biochar surfaces is part of the rhizosphere's removal of soil pollutants, reducing TE(s) availability to plants \u003cb\u003e(\u003c/b\u003eZhou et al. \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). \u003cb\u003eRees et al. (2014)\u003c/b\u003e found that applying BC (80% coniferous and 20% hardwood chips, 450\u0026deg;C) increased TE(s) immobilization in the soil and adsorption of TE(s) unique to BC mineral phases. Organic and mineral components found in BC may play a key role in TE(s) adsorption \u003cb\u003e(\u003c/b\u003eXu and Chen \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2015\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. According to Xu and Chen (\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2015\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e, the water-soluble part of BC adsorbed Ni significantly more than the HCl-soluble ashes and insoluble silicon oxide solids. Biochar treatment (maple wood at 450\u0026deg;C) immobilized TE(s), Cu, Zn, and Pb in sandy loam urban soil. Similarly, biochar generated from gigantic Miscanthus lowered the mean cumulative Zn and Cd fluxes, which might be attributed to both lower TE(s) concentrations in the soil solution and decreased drainage \u003cb\u003e(\u003c/b\u003eKargar et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Mendez et al. (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2014\u003c/span\u003e) found that applying paper sludge biochar (made at 500\u0026deg;C) to soil and incubating it for 77 days reduced the amount of leached and accessible Ni. Puga et al. (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2015a\u003c/span\u003e) found that applying biochar (sugarcane straw at 700\u0026deg;C) reduced DTPA extractable Zn, Pb, and Cd from the soil as well as the concentrations of these TE(s) in the pore water. Similarly, \u003cb\u003eAl-Wabel et al. (2015)\u003c/b\u003e found that BC (Concarpus waste, 400\u0026deg;C) significantly reduced AB-DTPA-extractable TE(s) (Mn, Zn, Cd, Cu, and Pb) in soil.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eThis research elucidates KOH's chemical activation mechanism during biomass pyrolysis, offering novel insights into the potential chemical reaction pathways between KOH and oxygen-containing groups. During the biomass pyrolysis process, KOH engages with active oxygen-containing species within the biomass, removing a substantial portion of oxygen-containing groups and forming numerous vacancies. In addition, this study extends the scope of activation techniques to include ZnCl\u003csub\u003e2\u003c/sub\u003e chemical activation, resulting in activated carbon samples with notably increased specific surface areas compared to the raw biochar material. However, it is worth noting that the specific surface area achieved with ZnC\u003csub\u003el2\u003c/sub\u003e activation does not reach the levels attained with KOH. In light of these findings, sugarcane bagasse emerges as a more promising raw material for biochar production when compared to olive mill waste, potentially opening avenues for more effective and sustainable biochar applications.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eCEC\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCation Exchange Capacity\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eCNT\u003c/b\u003e\u003csub\u003e\u003cb\u003eS\u003c/b\u003e\u003c/sub\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCarbon Nanotubes\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eEC\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eElectrical Conductivity\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eFTIR\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eFourier-transform infrared spectroscopy\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eNP\u003c/b\u003e\u003csub\u003e\u003cb\u003eS\u003c/b\u003e\u003c/sub\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eNatural nanoparticles\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eOMW\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eOlive Mill Waste\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eROS\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eReactive Oxygen species\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eSCB\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eSugar cane bagasse\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eSEM\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eScanning electron microscopy\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eTEM\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eTransmission electron microscopy\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eTE\u003c/b\u003e\u003csub\u003e\u003cb\u003eS\u003c/b\u003e\u003c/sub\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eTrace Elements\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eACKNOWLEDGEMENT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe highly appreciate the support and cooperation of the Central Laboratory of the Agriculture Faculty at Menofia University, Egypt, for their invaluable assistance during the measurements for this work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of interests\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eETHICS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDuality of interest:\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no conflict of interest in the publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions:\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAuthors Nehal.A.Ali and Basma.M.Ahmed write the original draft and substantial contribution to analysis and interpretation of data S.A.Radwan, E.A.Abou Hussien edit and finalize the manuscript. All authors read and agree for submission of manuscript to the journal.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNo specific funding was received for this work\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAissaoui, M. H., Trabelsi, A. B. H., Abidi, S., Zaafouri, K., Haddad, K., Jamaaoui, F., Leahy, J. J., \u0026amp; Kwapinski, W. (2021). Sustainable biofuels and biochar production from olive mill wastes via co-pyrolysis process. \u003cem\u003eBiomass Conversion and Biorefinery\u003c/em\u003e, 1\u0026ndash;14.\u003c/li\u003e\n\u003cli\u003eAl-Wabel MI, Usman AR, El-Naggar AH, Aly AA, Ibrahim HM, Elmaghraby S, Al-Omran A (2015) Conocarpus biochar as a soil amendment for reducing heavy metal availability and uptake by maize plants. Saudi J Biol Sci 22:503\u0026ndash;511\u003c/li\u003e\n\u003cli\u003eAlmaroai, Y. A., A. R. Usman, M. Ahmad, D. H. Moon, J. S. Cho, Y. K. Joo, C. 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(2020). \u003cem\u003eBiochars from solid digestates as sorbing materials for metal ( loid ) s removal from water Suchanya Wongrod To cite this version : HAL Id : tel-02474462 Tesi di Dottorato \u0026ndash; Th\u0026egrave;se \u0026ndash; PhD thesis \u0026ndash; V\u0026auml;it\u0026ouml;skirja Suchanya Wongrod Biochars from solid digestates \u003c/em\u003e.\u003c/li\u003e\n\u003cli\u003eXu Y, Chen B (2015) Organic carbon and inorganic silicon speciation in rice-bran-derived biochars affect its capacity to adsorb cadmium in solution. J Soils Sediments 15:60\u0026ndash;70\u003c/li\u003e\n\u003cli\u003eZheng, S., Fan, J., Yu, F., Feng, B., Lou, B., Zou, Q., ... \u0026amp; Liang, T. (2020). Viral load dynamics and disease severity in patients infected with SARS-CoV-2 in Zhejiang province, China, January-March 2020: retrospective cohort study. bmj, 369.\u0026rlm;\u003c/li\u003e\n\u003cli\u003eZhou F, Wang H, Zhang W, Qiu R (2015) Pb (II), Cr (VI) and atrazine sorption behavior on sludge-derived biochar: role of humic acids. Environ Sci Pollut Res doi:10.1007/s11356-015-4818-7\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","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":"Nano biochar, Elemental composition, Soil immobilization and Activation","lastPublishedDoi":"10.21203/rs.3.rs-4430795/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4430795/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eThis study examines the production of biochar from sugarcane bagasse and olive mill waste, focusing on its elemental composition, form, and functional groups, and its impact on soil immobilization.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThe study utilized various techniques like SEM, TEM, and FTIR to describe the biochars produced from SCB and OMW, which were prepared through ball-milling and activation treatments.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe study explores KOH interaction pathways during biomass pyrolysis, revealing larger surface areas and consistent decrease in soil trace element levels.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eThis study introduces ZnCl\u003csub\u003e2\u003c/sub\u003e chemical activation and activated carbon samples, enhancing understanding of activation procedures and biochar nanoparticles' benefits. 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