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Iron ore tailings (IOT) are industrial solid wastes that pose environmental threats. This study prepared IOT-biochar composite materials as multifunctional soil conditioners through an in-situ growth method. Biochar served as a carrier to improve the dispersity and reactivity of IOT in soil. The IOT-biochar composite (FeOT-BC) showed balanced impacts on soil properties, increasing pH, organic matter and available nutrients compared to IOT alone. This was due to the buffering effects of biochar. In pot experiments, FeOT-BC significantly promoted rice plant growth compared to IOT alone. The improvements were attributed to the improved soil fertility and increased microbial activities induced by biochar. The results suggest that integrating IOT with biochar can mitigate the negative effects of tailings and convert them into a value-added product. The biochar component can optimize the performance of IOT by moderating soil acidification, enhancing nutrient release from iron minerals, and stimulating microbial activities. The IOT-biochar composite materials integrate the functionalities of both components for optimized soil conditioning effects, providing a promising strategy for comprehensive tailings utilization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Waste furfural residue is deliberated as feedstock for pyrolysis/gasification. • Furfural residue is used to prepare catalysts with one-step method for tar cracking. • Increase in cracking temperature is helpful to the catalytic ability of catalysts. • Ni-loaded catalyst shows higher thermal stability and tar conversion efficiency. • Mechanism of tar catalytic cracking over catalysts is proposed. This study proposed an innovative strategy of catalytic cracking of tar during biomass pyrolysis/gasification using furfural residue derived biochar-based catalysts. Fe, Co, and Ni modified furfural residue char (FRC-Fe, FRC-Co, and FRC-Ni) were prepared by one-step impregnation method. The influences of cracking temperature and metal species on the tar cracking characteristics were investigated. The results showed that the tar conversion efficiency for all catalysts were improved with the cracking temperature increasing, the higher tar conversion efficiency achieved at 800 °C were 66.72 %, 89.58 %, 84.58 %, and 94.70 % for FRC, FRC-Fe, FRC-Co, and FRC-Ni respectively. FRC-Ni achieved the higher gas (H 2 , CO, CH 4 , CO 2) yield 681.81 mL/g. At 800 °C, the catalyst (FRC-Ni) still reached a high tar conversion efficiency over 85.90 % after 5 cycles. SEM-EDS results showed that the distribution of Ni particles on the biochar support was uniform. TGA results demonstrated that FRC-Ni exhibited better thermal stability. XRD results indicated that there was no significant change in the grain size of Ni before and after the reaction. The FRC-Ni catalyst was reasonably stable due to its better anti-sintering and coke-resistant capabilities. [ABSTRACT FROM AUTHOR]

Soil salinization is a common form of land degradation in coastal regions. The Yellow River Delta is a typical coastal saline‐alkali soils distribution region, with saline‐alkali soils accounting for nearly half of the total area of the region. In view of the lack of fresh water in the region, the use of brackish water and biochar made from agricultural waste to improve coastal saline‐alkali soils has a good application prospect, but there are fewer studies on this at present. To explore water conservation, fertilization, and yield enhancement solutions appropriate for saline‐alkali soils in the Yellow River Delta region, this study focused on investigating the impact of biochar addition on the fertility, enzyme activity, and winter wheat yield in saline‐alkali soils under brackish water irrigation conditions. The research was conducted through outdoor potting experiments, utilizing a local moderately saline‐alkali soil as the subject of study. The study design established three different irrigation water mineralization levels (0, 2, and 4 g L−1) during the research. Two types of biochar, wheat straw biochar (WB) and corn straw biochar (CB) were used with four different applications (0, 5, 10, and 20 t ha−1). There were 21 treatments; each replicated three times. The research findings indicated that brackish water irrigation adversely affected soil fertility and soil alkaline phosphatase activity and soil sucrase activity but increased soil urease activity and soil peroxidase activity. In contrast, biochar application improved soil fertility and enzyme activities. The soil fertility and enzyme activities of K2Y10 treatment was higher than that of CK (fresh water, no biochar application) except for soil total nitrogen, which increased by 5.5%–71.2%. While brackish water irrigation decreased winter wheat yield. Biochar application increased winter wheat yield, with the K2Y10 treatment showing the highest yield under brackish water irrigation conditions, and increased by 17.7% compared to CK. In conclusion, the study recommends a combination of water‐saving measures, fertilizer cultivation, and yield increase strategies to improve saline‐alkali soils in the Yellow River Delta region effectively. Specifically, irrigating with 2 g L−1 brackish water and application 10 t ha−1 of CB demonstrated greater efficacy in addressing the challenges of saline‐alkali soils in the region. [ABSTRACT FROM AUTHOR]

Increasing scientific knowledge on the improvement of coastal saline soils is critical for spatially expanding coastal development. Biochar and polyacrylamide (PAM) are popular soil amendments, however, it remains unclear how they affect water and salt transport by regulating soil microstructure characteristics. In this study, we conducted a five‐year rice barrel trial and investigated the changes in the aggregates and microstructure of saline soils after adding biochar with three different application rates (B1 = 0%, B2 = 2%, and B3 = 5%, mass ratio) and PAM with three different application rates (P1 = 0%, P2 = 0.4‰, and P3 = 1.0‰, mass ratio), and simulated the water and salt transport. Results showed that at B1 and B2 treatments, soil μ‐CT porosity in 2020 increased by 89.8% and 208.0%, respectively, with respect to that in 2016. The development of soil mesopore structure was promoted at B2 treatments, whereas the P2 and P3 treatments promoted the development of the soil macrostructure. Compared with those of the blank control, soil internal mean water flow rate increased by 22.2% at B2 treatments and 69.2% at P2 treatments, respectively. However, their increases were less pronounced at B3 treatments and the water flow rate decreased by 50.5% at P3 treatments. It might be reasonably attributed to the reason that porous biochar helped the formation of soil pore structure while an excessive amount of biochar blocked soil pores. Furthermore, PAM amendment helped to form soil aggregates while an excessive amount of viscous PAM might block soil pores or form a viscous layer. The time corresponding to the maximum salt concentration was negatively correlated with soil μ‐CT porosity (R2 = 0.27) and pore connectivity density (R2 = 0.29). Our findings indicate that appropriate amounts of biochar and PAM can help improve saline soil structure in coastal areas, improve their hydraulic properties, and alleviate salt stress. [ABSTRACT FROM AUTHOR]

Background Aims Methods Results Conclusion Biochar can enhance phytoremediation in petroleum hydrocarbon polluted soils, making it an intriguing soil amendment option for remediating polluted soil. Biochar can improve the fertility of depleted soils through a range of mechanisms. This study can contribute valuable insights into the origin of biochar and enhance our understanding of the efficacy of different biochar types in remediating petroleum hydrocarbon polluted soils.To assess the efficacy of different biochar types and plant growth in remediating petroleum hydrocarbon polluted soils.A field experiment was conducted at the automobile workshop (commonly called mechanic village) from July to October 2021, using a randomized complete block design. The land was sectioned into designated plots with three replicates. Maize stalk biochar (MSB) and nipa palm biochar (NPB) were treated differently in each plot at a rate of 20 t ha−1. Plots containing no biochar were used as controls. Initial and final soil analyses were conducted.Preliminary soil assessments revealed higher values of soil bulk density (1.51 g cm−3), moisture content (35.02%), organic carbon (41.01 g kg−1), cation exchange capacity (13.27 cmol kg−1), total petroleum hydrocarbon content (PHCt) (775.83 mg kg−1), cadmium (Cd) (5.41 mg kg−1), chromium (Cr) (25 mg kg−1), lead (Pb) (33.51 mg kg−1), and zinc (Zn) (0.91 mg kg−1) in the polluted soil than in the unpolluted counterpart. The polluted soil displayed lower hydraulic conductivity (Ks) (1.17 cm h−1), available phosphorus (69.46 mg kg−1), manganese (Mn) (6.38 mg kg−1) and iron (Fe) (4.18 mg kg−1) contents than the unpolluted soil. The PHCt, Cd, and Cr were significantly decreased following the application of biochar. NPB recorded the lowest petroleum hydrocarbon (19%), lead (37%), manganese (57%), and zinc (69%) contents, whereas MSB had the lowest cadmium (50%) and chromium (27%) contents when compared with the control. Between heavy metal accumulations in the leaves and fruits, a greater accumulation of Cd, Cr, and Pb was found in the leaves, whereas Ni accumulation was found in the fruits. The highest Cd (47.0 mg kg−1) and Ni (8.3 mg kg−1) accumulations in the leaves were recorded in NPB treated plots. Similarly, Cd (5.3 mg kg−1), Cr (3.7 mg kg−1), Pb (21.6 mg kg−1), and Ni (23.4 mg kg−1) accumulation in the fruits recorded the highest values in the NPB treated plots. The NPB plants were the tallest compared with the other treatments. In addition, NPB plants had the widest leaf area compared with other treatments.The results indicated that the amendment of NPB may be suitable for the phytoremediation of soils polluted with petroleum hydrocarbons. [ABSTRACT FROM AUTHOR]

Carbonization of waste material into functional carbonaceous material is a benign way of utilizing biomass. Herein, we report the decoration of SnS2 nanoparticles on the biochar carbonaceous material using a facile hydrothermal synthetic strategy. The biomass collected from staminate flowers was pyrolyzed to obtain a biochar material containing a hydrophilic surface that creates an efficient environment for the decoration of SnS2 nanoparticles. The SnS2 decoration was thoroughly investigated using state-of-the-art instrumentation techniques. The morphological investigations indicate the formation of flower-shaped SnS2 nanoparticles with a sufficiently exposed surface for effective surface activities. These include the photodegradation of the methylene blue (MB) dye and electrochemical sensing of Pb2+ and Hg2+ ions. The SnS2@BC composite exhibits superior photocatalytic activity for the degradation of MB. Almost 95% of MB is removed within 60 min of contact time by a collaborative effect of adsorption and sunlight-driven photocatalysis. The removal of MB followed pseudo-first-order kinetics with a high K1 value of ca. 0.013 min−1. The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) traces of the SnS2@BC modified glassy carbon electrode (GCE) show a decent electrochemical response with limits of detection of ca. 0.28 and 0.55 μM in the case of Pb2+ and Hg2+ respectively. Furthermore, the DFT studies were carried out on a simulated model material and the results were in line with the experimental data. This work provides an economical treatment method for the photodegradation and electrochemical sensing of toxic contaminants present in wastewater. [ABSTRACT FROM AUTHOR]

\nHIGHLIGHTSBiochar is a soil amendment made from organic waste pyrolysis that has the potential to enhance crop growth and reduce soil contamination. A recent study examined the effects of biochar application on rice plant growth, yield, biomass, and total petroleum hydrocarbon (TPH) contamination in soil. The study included four treatments: control, biochar (2.0% and 4.0% addition), TPH (4.0%, 6.0%, and 8.0%), and biochar+TPH. Results showed that biochar application was effective in mitigating the negative effects of TPH contamination on soil-physiochemical properties, increasing soil pH, organic matter, and available nutrients. Additionally, biochar application significantly increased rice plant height compared to the control and mitigated the negative impact of TPH on rice plant height in TPH-contaminated soil. Biochar application at 4.0% and 6.0% resulted in higher grain yield and biomass than the control group under all TPH contamination levels, with 6.0% being the most effective. Overall, the study highlights the potential of biochar as a sustainable approach for crop production in contaminated areas. However, further research is required to understand the underlying mechanisms, sustainability, and long-term effects of biochar application in agricultural systems. SBB has the potential to mitigate the negative effects of TPH contamination on soil properties.SBB can increase soil pH, organic matter, and available nutrients, making it a valuable tool for soil remediation.SBB reduces TPH removal from contaminated soil, possibly due to adsorption or soil property modifications.SBB has a positive effect on rice height, mitigating the negative impact of TPH contamination.Higher levels of SBB result in taller rice plants, and lower levels of TPH result in taller rice plants.SBB application at 4.0% and 6.0% improves grain yield and biomass across all TPH contamination levels.SBB has promising potential as a sustainable strategy for managing contaminated soils for crop production.SBB has the potential to mitigate the negative effects of TPH contamination on soil properties.SBB can increase soil pH, organic matter, and available nutrients, making it a valuable tool for soil remediation.SBB reduces TPH removal from contaminated soil, possibly due to adsorption or soil property modifications.SBB has a positive effect on rice height, mitigating the negative impact of TPH contamination.Higher levels of SBB result in taller rice plants, and lower levels of TPH result in taller rice plants.SBB application at 4.0% and 6.0% improves grain yield and biomass across all TPH contamination levels.SBB has promising potential as a sustainable strategy for managing contaminated soils for crop production. [ABSTRACT FROM AUTHOR]

Highlights In this study, three types of biochar including wood biochar (WB), rice husk biochar (RHB), and bamboo biochar (BB) were used as fillers to mix with wood flour (WF), polypropylene (PP), and maleic anhydride polypropylene (MAPP) to prepare wood polymer biochar composites (WPBC). The influences of biochar types and addition amounts (10 wt%, 20 wt%, 30 wt%, and 40 wt%) on the mechanical properties, dimension stability, and thermal stability of WPBC were investigated. The results showed that the water absorption rate and thickness swelling rate of WPBC were lower than control group due to the hydrophobic nature of the biochar. Additionally, the presence of biochar was beneficial to the interfacial bonding and stress transmission in composites, resulting in better mechanical properties. Composites containing 20 wt% RHB showed the highest flexural modulus among all, which increased by 11.27% compared to control group. Adding WB also enhanced the tensile and impact strength of composites at a loading level of 10 wt%, with the value of 39.10 MPa and 15.55 KJ/m2, respectively. The thermal stability and flame retardancy of WPBC was improved due to the presence of SiO2 in biochar, which could hinder heat transmission and thermal degradation during combustion process. Concurrently, the rate of heat release and smoke generation in WPBC also decreased significantly. The oxygen limiting index (LOI) of composites with 20 wt% RHB was as high as 26.64%, increasing by 30.14% compared to control group. The results suggested that biochar was a promising alternative to commercial additives for the cost‐effective production of composites. Effects of biochar loading level and type were compared. Enhanced the mechanical properties by optimizing interfacial bonding. Biochar improved the dimensional and thermal stability. Biochar is a versatile and cost‐effective additive. [ABSTRACT FROM AUTHOR]

Biochar is a promising pyrolysed carbon-enriched soil amendment and has excellent properties for agriculture production and to remediate environmental pollution. A set of reviews were conducted on biochar production by pyrolysis process from various waste biomass which has drawn extensive interest due to the low cost of production with several benefits. As many potential technologies have been developed, there are still several knowledge gaps that have been identified for some key points to contribute a comprehensive study towards soil fertility, nutrient and water retention, soil microbial activity, plant growth and yield, pollution remediation, mitigation of greenhouse gas emission and an improvement in the farmer's economy to achieve maximum profit by adopting environmentally friendly technique "pyrolysis". Therefore, this review explored a detailed study on food waste biochar production by the pyrolysis process and its impact on different applications as an amendment. Slow pyrolysis process at low and medium temperatures is a potential amendment for agriculture production and soil and water remediation by enhancing biochar properties like carbon, BET surface area, cation exchange capacity, zeta potential, and nutrient content, etc. with minimum ash content. The biochar enhances soil water and nutrient retention capacity, crop yield, and improved microbial community at different soil quality. Additionally, food waste to biochar is a realistic adsorbent and economical carbon sequester to mitigate GHG emissions. This review conducted a brief assessment of the knowledge gaps and future research directions for researchers, encouraging investigators, stakeholders, and policymakers to make the best possible decision for food waste valorization. Highlights: • Valorization of food waste to biochar is a promising amendment for agriculture and soil–water remediation. • Lower and medium pyrolysis temperatures qualitatively changed all aspects of biochar properties. • Biochar improves soil fertility, microbial activity, soil water and nutrient retention capacity, and plants growth. • Biochar is a good carbon sequestrator to mitigate greenhouse gas and a bioeconomy product for the farmer's community and policymakers. [ABSTRACT FROM AUTHOR]

Background: Hundreds of millions of tons coal fly ash are produced annually to support economic development and industrial production. However, directly applying coal fly ash to agricultural production can decrease the land productivity and pose a threat to the ecosystem due to the poor physicochemical properties and seriously heavy metal pollution. Methods: In this study, a field experiment to investigate the effects of coal fly ash as a soil amendment was conducted in Hebei province, China. The coal fly ash (CFA) soil field was mixed with the carrier soil (CS, without containing coal fly ash) at different rates (0–40% mass content) in the 0–20 cm layer of top soil and then mixed with a rotovator. The soil was then amended with 0.45–1.80 kg·m− 2 of G1 soil amendment for planting corn. Purpose: The purpose of this study is to investigate the response mechanism of soil microbial community activities, and soil physicochemical properties to soil amendment and carrier soil in coal fly ash soil. Key results: The study found that the G1 amendment, which consisted of humic acid, polyacrylamide, zeolite powder, and FeSO4·7H2O, improved the soil chemical properties and physical structure by increasing soil bulk density and macroaggregates. The highest corn yield was observed in B5 (20% CS and 1.3500 kg·m− 2 G1). Meanwhile, the abundance of microorganisms that facilitate the circulation of soil nutrients such as Acidobacteria (77.05%), Sphingomonas (25.60%), Nitrospira (20.78%), Streptomyces (11.32%), and Gaiella (10.20%) was increased. Conclusions: Overall, our results indicate that the use of coal fly ash soil as a amendment can enhance soil sustainability by improving soil microbial functions. These findings provide a reference for the development and application of coal fly ash soil amendments. [ABSTRACT FROM AUTHOR]

Sandy soils are characterized by low soil moisture content and nutrient retention due to high permeability, limiting crop productivity and threatening food security in arid and semi-arid regions worldwide. Various reclamation technologies have been developed to address these challenges, but their effectiveness has not been comprehensively evaluated. This systematic review evaluated the performance of 42 sandy soil reclamation technologies reported in 144 studies from 27 countries that met specified selection criteria. Performance was evaluated based on response ratio (RR) of aboveground biomass and grain yield, as indicators of productivity, and soil moisture content and soil organic carbon (SOC), as indicators of soil health. The 42 technologies employed four main soil amendments: biochar, organic amendments, organic amendments combined with biochar, and soft rock. Overall, all technologies increased productivity and improved soil health. Biochar application was found to be the most effective technology, increasing grain yield by 51.6%, aboveground biomass by 67.4%, soil moisture content by 17.3%, and SOC by 74.2%. Soft rock application increased grain yield by 20.3%, aboveground biomass by 27.6%, soil moisture content by 54.5%, and SOC by 12.8%. Organic amendments increased grain yield by 48.7%, aboveground biomass by 45.6%, soil moisture content by 20.8%, and SOC by 36.7%. However, the combination of biochar and organic amendments showed lower improvements, with increases of 25.4%, 15.6%, 1.3%, and 25.4% for grain yield, aboveground biomass, soil moisture content, and SOC, respectively. Our conclusion is that the findings provide strong evidence that sandy soil reclamation technologies can significantly improve crop productivity and food security. Considering the variability in technologies responses across continents, there is need for further research to determine the optimal technology for specific locations, crops, and management practices. [ABSTRACT FROM AUTHOR]

Background: Water stress is a major danger to crop yield, hence new approaches to strengthen plant resilience must be developed. To lessen the negative effects of water stress on wheat plants, present study was arranged to investigate the role of synergistic effects of biochar, trans-zeatin riboside (t-ZR), and Azospirillum brasilense on soil improvement and enzymatic activity in water-stressed wheat. Results: In a three-replication experiment comprising of four treatments (T0: Control, T1: Drought stress (DS), T2: DS + t-ZR with biochar, T3: DS + A. brasilense with biochar), we observed notable improvements in soil quality and enzymatic activities in water-stressed wheat plants with the application of t-ZR and A. brasilense with biochar. In drought stress, Treatment having the application of A. brasilense with biochar performs best as compared to the other and significant increased the enzymatic activities such as peroxidase (7.36%), catalase (8.53%), superoxide dismutase (6.01%), polyphenol oxidase (14.14%), and amylase (16.36%) in wheat plants. Different enzymatic activities showed different trends of results. Soil organic C, dissolved organic C, dissolved organic N also enhanced 29.46%, 8.59%, 22.70% respectively with the application of A. brasilense with biochar under drought stress condition. Conclusions: The synergistic action of A. brasilense and biochar creates an effective microbiological environment that supports essential plant physiological processes during drought stress. This enhancement is attributed to improved soil fertility and increased organic matter content, highlighting the potential of these novel strategies in mitigating water stress effects and enhancing crop resilience. [ABSTRACT FROM AUTHOR]

As for Atrazine (C8H14ClN5) degradation in soil, iron (Fe)-manganese (Mn) bimetallic biochar composites were proved to be more efficient for persulfate (PS) activation than monometallic ones. The atrazine removal rates of Fe/Mn loaded biochar + PS systems were 2.17–2.89 times higher than Fe/Mn loaded biochar alone. Compared with monometallic biochar, the higher atrazine removal rates by bimetallic biochar (77.2–96.7%) were mainly attributed to the synergy degradation and adsorption due to the larger amounts of metal oxides on the biochar surface. Atrazine degradation in Fe-rich biochar systems was mainly attributed to free radicals (i.e., SO 4 · - and ·OH) through oxidative routes, whereas surface-bound radicals, 1O2, and free radicals were responsible for the degradation of atrazine in Mn-rich biochar systems. Furthermore, with a higher ratio of Fe(II) and Mn(III) formed in Fe-rich bimetallic biochar, the valence state exchange between Fe and Mn contributed significantly to the more effective activation of PS and the generation of more free radicals. The pathways of atrazine degradation in the Fe-rich bimetallic biochar systems involved alkyl hydroxylation, alkyl oxidation, dealkylation, and dechlorohydroxylation. The results indicated that bimetallic biochar composites with more Fe and less Mn are more effective for the PS-based degradation of atrazine, which guides the ration design of easily available carbon materials targeted for the efficient remediation of various organic-polluted soil. Highlights: Both Fe- and Mn-rich bimetallic biochar can effectively activate persulfate, but Fe-rich biochar is superior. Atrazine degradation in Fe-rich biochar systems was attributed to free radicals through oxidative routes. Atrazine degradation pathways involved alkyl hydroxylation, alkyl oxidation, dealkylation, and dechlorohydroxylation. [ABSTRACT FROM AUTHOR]

Biochar is a promising solution to alleviate the negative impacts of salinity stress on agricultural production. Biochar derived from food waste effect was investigated on three plant species, Medicago sativa, Amaranthus caudatus, and Zea mays, under saline environments. The results showed that biochar improved significantly the height by 30%, fresh weight of shoot by 35% and root by 45% of all three species compared to control (saline soil without biochar adding), as well as enhanced their photosynthetic pigments and enzyme activities in soil. This positive effect varied significantly between the 3 plants highlighting the importance of the plant-biochar interactions. Thus, the application of biochar is a promising solution to enhance the growth, root morphology, and physiological characteristics of plants under salt-induced stress. [ABSTRACT FROM AUTHOR]

Natural fiber‐reinforced composites (NFRCs) suffer from water absorption and low temperature stability, resulting in fiber degradation and subsequent material failure. Built‐in piezoresistive sensors are investigated to monitor the deformation/strain of the component. As a low‐cost material from renewable resources biochar particles derived from olive stones were applied on flax plies and yarn bundles that served as model systems. Carbon black samples as petrochemical variants were used as a reference material. Biochar and carbon black‐covered fiber systems were laminated in epoxy resin followed by tensile tests. The electrical resistance was recorded simultaneously during testing. Biochar with a broad size distribution from nano to high micrometer range (D < 200 μm) was superior in sensor performance compared to carbon black and biochar with a smaller particle size range D < 20 μm. Gauge factors (GF) of NFRC samples with integrated biochar particles reached 30–80 while carbon black could not exceed a GF of 8. To obtain maximum GFs, yarn count of flax yarn/ply substrate should be as thin as possible, but still enable percolation of the adhering particle network. Comparatively large particle size was identified as a contributing factor enabling the high GF for coarse biochar compared to carbon black. Highlights: A nonfossil biochar built‐in piezoresistive sensor in natural fiber‐reinforced composites was fabricatedDeposing biochar directly on flax fibers facilitates processingThe biochar piezoresistive sensor exhibits superior sensitivity compared to carbon black [ABSTRACT FROM AUTHOR]

Persistent free radicals (PFRs) are emerging substances with diverse impacts in biochar applications, necessitating accurate prediction of their content and types prior to their optimal use and minimal adverse effects. This prediction task is challenging due to the nonlinearity and intricate variable relationships of biochar. Herein, we employed data-driven techniques to compile a dataset from peer-reviewed publications, aiming to systematically predict the PFRs by developing supervised machine learning models. Notably, extreme gradient boosting (XGBoost) model exhibited the best predictive performance for both regression and classification tasks in predicting the PFRs, achieving a test R2 value of 0.95 for PFR content prediction, along with an Area Under the Receiver Operating Curve (AUROC) of 0.92 for PFR type prediction, respectively. Based on XGBoost model, a graphical user interface (GUI) was developed to access PFRs predictions. Analysis of feature importance revealed that the biochar properties, such as metal/non-metal doping, pyrolysis temperature, carbon content, and specific surface area were identified as the four most significant factors influencing PFRs contents. Regarding the types of PFRs in biochar, specific surface area, pyrolysis temperature, carbon content, and feedstock were top-ranked influencing factors. These findings provide valuable guidance for accurately predicting both the contents and types of PFRs in biochar, and also hold significant potential for highly efficient utilization of biochar across various applications. Highlights: • Recognizing dual nature of PFRs, a machine-learning framework predicts them in biochar. • XGBoost excels, achieving an R2 (0.95) for PFR content and an AUROC (0.92) for PFR type. • Important factors of PFR: doping, pyrolysis temp, carbon, and surface area. • GUI enhances accessibility, enabling PFR predictions before biochar preparation. [ABSTRACT FROM AUTHOR]

Using Euryale ferox husk as raw material, pristine biochar (EBC), Bi2MoO6-modified biochar (BM-EBC), and BiFeO3-modified biochar (BF-EBC) were prepared and employed for decontaminating Congo red (CR) from wastewater. Compared with EBC (217.59 mg/g) and BF-EBC (359.49 mg/g), a superior adsorption capacity of 460.77 mg/g was achieved by BM-EBC. Based on the evaluation results of the Freundlich and pseudo-second-order models, multilayer chemisorption was suggested as the adsorption mechanism. The adsorption process of BM-EBC was spontaneous and endothermic, and the rate-limiting step pertained to liquid film diffusion and intraparticle diffusion. The underlying removal mechanism was explored via SEM, BET, FTIR, XPS, Raman spectra, and Zeta potential analyses. The introduction of bismuth oxymetallates with their high number of M–O (M: Bi, Mo, Fe) structural elements provided the adsorbent with enlarged surface areas and reinforced oxygen functional groups, thereby promoting pore filling, π-π interactions, hydrogen bonding, and complexation, leading to enhanced adsorption capacity. These results demonstrate that Euryale ferox husk biochar modified by bismuth oxymetallates has high prospects for valorizing biomass waste and removing CR from wastewater. [ABSTRACT FROM AUTHOR]

Biochar, as a potential adsorbent, has been widely employed to remove pollutants from sewage. In this study, a lignin-based biochar (CB-800) was prepared by a simple high-temperature pyrolysis using urban green waste (Cinnamomum camphora leaves) as a feedstock to remove norfloxacin (NOR) from water. Batch adsorption test results indicated that CB-800 had a strong removal capacity for NOR at a wide range of pH values. The maximum adsorption achieved in the study was 50.90 ± 0.64 mg/g at 298 K. The pseudo-first and second-order kinetic models and the Dubinin-Radushkevich isotherm fitted the experimental data well, indicating that NOR adsorption by CB-800 was a complex process involving both physi-sorption and chemi-sorption. The physical properties of CB-800 were characterized by SEM and BET. The mesoporous structures were formed hierarchically on the surface of CB-800 (with an average pore size of 2.760 nm), and the spatial structure of NOR molecules was more easily adsorbed by mesoporous structures. Combined with Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis, it was showed that the main NOR adsorption mechanisms by CB-800 included ion exchange, π-electron coordination, hydrogen bonding, and electrostatic adsorption. Meanwhile, the reduction of C = O and pyridine nitrogen, and the presence of C-F2, also indicated the occurrence of substitution, addition, and redox. This study not only determined the reaction mechanism between biochar and NOR, but also provides guidance to waste managers for the removal of NOR from water by biochar. It is envisaged that the results will broaden the utilization of urban green waste. [ABSTRACT FROM AUTHOR]

Biochar application can alleviate the adverse effects of saline-alkali stress on crops. However, the long-term effects of one-off biochar application on soil physicochemical properties, salt concentration, nutrient availability, soil enzyme activities, and rice yield under highly saline-alkali paddy soils remain unclear. Here, a 6-year paddy field study was conducted in a saline-alkali paddy field using two nitrogen application levels (0 and 225 kg ha−1) and four biochar application rates [0 (T0), 1.5% (T1.5), 3.0% (T3.0), and 4.5% (T4.5) biochar, w/w]. The results showed that compared with T0, the bulk density (BD) under T1.5, T3.0, and T4.5 treatments significantly decreased by 11.21%, 16.33%, and 25.57%, while total porosity (Tp) and saturated hydraulic conductivity (Ks) increased by 19.15–27.34% and 3217.78–5539.83%, respectively. Biochar consistently improved soil macro-aggregates, mean weight diameter (MWD), and the percentage of water-stable aggregates (PWSA) over the years. Additionally, one-off application of biochar continuously reduced the soil Na+ concentration, Na+/K+ ratio, Na+/Ca2+ ratio, saturated paste extract (ECe), exchangeable sodium percentage (ESP), and sodium adsorption ratio (SARe). However, it reduced the pH in 2021 and 2022 only. It enhanced the concentration of K+, Ca2+, Mg2+, and cation exchange capacity (CEC) over the 6-year study, indicating its longer-term positive impact. Furthermore, the one-off biochar application, especially under high application rate treatments (T3.0 and T4.5), significantly and continuously improved nutrient availability and soil enzyme activities. However, alkali-hydrolysable nitrogen (AN) decreased in the initial year of biochar application. The grain yield of T1.5, T3.0, and T4.5 surpassed that of T0 by 116.38%, 141.24%, and 145.20%, respectively. Notably, the rice yield reached its peak with the treatment of 3.0% (w/w) in all 6 years of study period. These findings offered new perspectives on repairing and improving soil quality and production ability of highly saline-alkali paddy soils. Highlights: A long-term (6-year), one-off application of biochar was conducted in a highly saline-alkali paddy field. Biochar consistently decreased soil BD, increased Tp, Ks, and improved soil aggregates. Biochar showed a sustained ability to alleviate saline-alkali stress. The continuous improvement of soil functions acted on the increase of rice yield. [ABSTRACT FROM AUTHOR]

Although biochar application to soils has been found to increase soil quality and crop yield, the biochar dispersion extent and its impacts on native soil organic carbon (SOC) has received relatively little attention. Here, the vertical and lateral migration of fine, intermediate and coarse-sized biochar (<0.5, 0.5–1 and 1–5 mm, respectively), applied at low and high doses (1.5–2 and 3–4% w/w, respectively), was tracked using stable isotope methods, along with its impact on native SOC stocks. Biochar was homogeneously mixed into the surface layer (0–7 cm depth) of a loamy sandy Acrisol in Zambia. After 4.5 y, 38–75% of the biochar carbon (BC) was lost from the applied layer and 4–25% was detected in lower soil layers (7–30 cm). Estimating BC mineralization to be no more than 8%, 25–60% was likely transported laterally out of the experimental plots. This conclusion was supported by observations of BC in the control plot and in soils up to 2 m outside of the experimental plots. These processes were likely progressive as recovery of BC in similar plots 1 year after application was greater in both surface and lower soil layers than after 4.5 y. Fine and intermediate-sized BC displayed the greatest downward migration (25.3 and 17.9%, respectively), particularly when applied at lower doses, suggesting its movement through soil inter-particle spaces. At higher dosages, fine and intermediate-sized particles may have clogged pore, so coarse biochar displayed the greatest downward migration when biochar was applied at higher doses. In the BC treatment plot soil profiles, native SOC stocks were reduced by 2.8 to 24.5% (18.4% on average), i.e. positive priming. However, some evidence suggested that the soils may switch to negative priming over time. The dispersion of biochar in soil should be considered when evaluating biochar's agronomic benefits and environmental effects. [ABSTRACT FROM AUTHOR]

Quantitative speciation of metals and their variability over time is a critical concept in environmental soil chemistry. Chromium is a heavy metal that has negative effects on the environment and human health. There have been several attempts to study the behavior of chromium in soils and its removal from soil. However, there is relatively little knowledge about the immobilization of chromium and its chemical speciation in contaminated and uncontaminated soils when different organic amendments are applied. A laboratory incubation experiment was conducted in a completely randomized design to evaluate the effect of organic amendments on the speciation of chromium in contaminated and uncontaminated soils. Four organic amendments were used: farmyard manure (FYM), rice straw compost (RSC), vermicompost (VC), and biochar (BC). Each of them was applied at 1% to contaminated as well as uncontaminated soils. In both the amended and unamended soils, chromate (CrO42-), bichromate (HCrO4−), and calcium chromate (CaCrO4) in soil-water system followed the order CrO42-> HCrO4−> CaCrO4. The application of FYM, RSC, VC, and BC significantly decreased the CrO42- and CaCrO4 in the soil-water system of both soils. However, only the application of BC affected the HCrO4− contaminated soils. In both soils, HCrO4− exists as the predominant chromium species in the pH range of 2.0 to 6.25. At pH 6.25, CrO42- and HCrO4− each contribute 50% of the total dissolved chromium in soil solution. CrO42- dominated in the system as the pH increased from 6.25 till 8.0. The maximum concentration of CrO42- was at pH 8.0. At pH <3.0, CrO3SO42- contributes less than 10%. Overall, organic amendments decreased the concentration of Cr species in both soils. However, the decrease in concentration was highly dependent on the nature of the amendment applied. Therefore, organic amendments can be exploited to remediate chromium-contaminated soils. [ABSTRACT FROM AUTHOR]

Hexavalent chromium [Cr(VI)] is a toxic metal that poses huge threat to environment and living bodies. Recently, microbial fuel cell (MFC) systems based on highly efficient cathodes have been widely applied for Cr(VI) remediation. In this study, a novel cathode loaded with magnetic nanoparticles (NPs)-doped biochar (Fe NPs/biochar) is introduced into a two-chamber MFC to investigate its power output and Cr(VI) reduction. Results showed that the removal efficiency of Cr(VI) using Fe NPs/biochar group was 98.19%, which is significantly higher than that of carbon felt (53.31%). The maximum power density of the Fe NPs/biochar is 8.41 times higher than that of carbon felt. An adsorption–reduction mechanism is obtained for Cr(VI) reduction of Fe NPs/biochar through characteristic and electrochemical analyses, such as scanning electron microscopy-energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry test. The microbial community analysis showed that the biofilm of the anode were enriched with electrochemically active bacteria, such as Geobacter and Pseudomonas , after operation. Thus, this study presents a highly effective electrode for enhancing the power output and Cr(VI) reduction for Cr(VI)-containing wastewater treatment. • The system showed high removal efficiency (∼98.19 %) for Cr(VI). • Fe NPs/Biochar cathode produced 144 mV of the bioelectricity. • Fe NPs can improve the performance of MFC as an electron shuttle carrier. [ABSTRACT FROM AUTHOR]

Biochar can improve soil health and fix CO2 by altering soil microenvironment, thus impacting the global carbon cycle and the change of soil ecological environment. Recent studies show that cotton byproduct-derived biochar is a potential effective amendment for soil improvement so that it could play an important role in agricultural and environmental conservation. In this work, research topics on cotton byproduct-derived biochar in soil in last decade and so are systematically reviewed for better understanding of the progresses of cotton byproduct-derived biochar in (i) the morphologic and physicochemical characterization, (ii) latest research hotspots and trends, (iii) the roles in soil reclamation, and (iv) relevant carbon sequestration mechanisms. Finally, the future research directions regarding cotton byproduct-derived biochar mingled to soil environment are discussed. Insight derived from this work would provide scientific basis for promoting more applications of cotton byproduct-derived biochar in soil ecological restoration and carbon fixation. [ABSTRACT FROM AUTHOR]

The pretreatment for torrefaction impacts the performance of biomass fuels and operational costs. Given their diversity, it is crucial to determine the optimal torrefaction conditions for different types of biomass. In this study, three typical solid biofuels, corn stover (CS), agaric fungus bran (AFB), and spent coffee grounds (SCGs), were prepared using fluidized bed torrefaction. The thermal stability of different fuels was extensively discussed and a novel comprehensive fuel index, "displacement level", was analyzed. The functional groups, pore structures, and microstructural differences between the three raw materials and the optimally torrefied biochar were thoroughly characterized. Finally, the biomass fuel consumption for household heating and water supply was calculated. The results showed that the optimal torrefaction temperatures for CS, AFB, and SCGs were 240, 280, and 280 °C, respectively, with comprehensive quality rankings of the optimal torrefied biochar of AFB (260) > SCG (252) > CS (248). Additionally, the economic costs of the optimally torrefied biochar were reduced by 7.03–19.32%. The results indicated that the displacement level is an index universally applicable to the preparation of solid fuels through biomass torrefaction. AFB is the most suitable solid fuel to be upgraded through torrefaction and has the potential to replace coal. [ABSTRACT FROM AUTHOR]

To develop valuable applications for the invasive weed Palmer amaranth, we utilized it as a novel biochar source and explored its potential for methyl orange adsorption through the synthesis of chitosan-encapsulated Palmer amaranth biochar composite microspheres. Firstly, the prepared microspheres were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy and were demonstrated to have a surface area of 19.6 m2/g, a total pore volume of 0.0664 cm3/g and an average pore diameter of 10.6 nm. Then, the influences of pH, dosage and salt type and concentration on the adsorption efficiency were systematically investigated alongside the adsorption kinetics, isotherms, and thermodynamics. The results reveal that the highest adsorption capacity of methyl orange was obtained at pH 4.0. The adsorption process was well fitted by a pseudo-second-order kinetic model and the Langmuir isotherm model, and was spontaneous and endothermic. Through the Langmuir model, the maximal adsorption capacities of methyl orange were calculated as 495.0, 537.1 and 554.3 mg/g at 25.0, 35.0 and 45.0 °C, respectively. Subsequently, the adsorption mechanisms were elucidated by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy investigations. It is indicated that electrostatic interactions, hydrogen bonding, π–π interactions and hydrophobic interactions between methyl orange and the composite microspheres were pivotal for the adsorption process. Finally, the regeneration studies demonstrated that after five adsorption–desorption cycles, the microspheres still maintained 93.6% of their initial adsorption capacity for methyl orange. This work not only presents a promising method for mitigating methyl orange pollution but also offers a sustainable approach to managing Palmer amaranth invasion. [ABSTRACT FROM AUTHOR]

Costa Rica produces a considerable, important quantity of wood residues. This waste can be pyrolyzed to produce charcoals as main products that can be effectively used as an energy source or to immobilize carbon for soil treatment. However, there is a lack of information about the pyrogenic carbonaceous materials (PCMs), such as charcoal or biochar, obtained at different pyrolysis temperatures. Hence, this study aimed to evaluate the quality of PCMs (physical, mechanical, ultimate analysis, and FTIR analysis) and charcoal characteristics (energetic properties and thermogravimetric analysis—TGA) and biochar characteristics (conductivity, pH, initial contact angle, and wetting rates) for four tropical wood residues produced in five temperatures (300 °C, 350 °C, 400 °C, 450 °C, and 500 °C). In general, pyrolysis temperature between 450 °C and 500 °C produced charcoals with lower values of density, moisture content, compression strength, volatiles, H and O content, and higher values of C and ash contents, conductivity, pH, initial contact angle, and wetting rates. FTIR and TGA analyses show that celluloses and lignin are pyrolyzed at these temperatures, so these temperatures are recommended. The range of 300–350 °C is not recommended, as these parameters were inverse. Multivariate analysis shows that (i) PCMs obtained at lower temperatures (300–350 °C) from Dipteryx panamensis, Hieronyma alchorneoides, and Tectona grandis belong to a cluster with poorer properties, indicating that these temperatures are not adequate for pyrolysis of these species; (ii) all the PCMs obtained from Gmelina arborea were grouped into one cluster, suggesting different PCM quality; and (iii) the PCMs produced from D. panamensis, H. alchorneoides, and T. grandis at 400–500 °C were grouped into another cluster with better properties, suggesting this pyrolysis temperature range as the best for these species. [ABSTRACT FROM AUTHOR]

The aim of this study was the characterization and evaluation of applicability as a soil amendment of biochar derived from rose pruning waste at different pyrolysis temperatures (200–500 °C) and process durations (20–60 min). The biochar properties were compared to the raw material. The biochars produced at 300 °C for 40 and 60 min demonstrated the best fuel properties. These variants showed high energy gain rates (77.6 ± 1.5% and 74.8 ± 1.5%, respectively), energy densification ratios (1.35 ± 0.00 and 1.37 ± 0.00, respectively), high heating values (24,720 ± 267 J × g−1 and 25,113 ± 731 J × g−1, respectively), and relative low ash contents (5.9 ± 0.5% and 7.1 ± 0.3%, respectively). Regarding fertilizer properties, such as pH value, ash content, heavy metal content, and pollutant elution, the biochars showed better qualities than the raw material. All tested biochar did not exceed the permissible values for heavy metals, including Cr, Cd, Ni, and Pb. The most optimal properties for soil amendments were noted for biochar variants of 400 °C for 40 min, 450 °C for 20 min, and 500 °C for 20 min. Generally, biochars produced at temperatures ≥400 °C did not inhibit root elongation, except for the material produced at 450 °C for 60 min (4.08 ± 23.34%). Biochars obtained at ≥300 °C showed a positive impact on seed germination (86.67 ± 18.48–100 ± 24.14%). [ABSTRACT FROM AUTHOR]

The regulation of the pyrolysis process is a key step in increasing the carbon sequestration capacity of biochar. The effect of K3PO4 addition on the yield, chemical composition, characteristic functional groups, macromolecular skeleton, graphite crystallites, and stability of biochar was studied in this paper using two-dimensional infrared correlation spectroscopy (2D-PCIS), X-ray photoelectron spectroscopy, Raman spectrum, and other characterization methods combined with thermal/chemical oxidation analysis. It is discovered that adding K3PO4 may effectively minimize the graphitization temperature range and increase biochar's yield, aromaticity, H/C ratio, and proportion of refractory/recalcitrant organic carbon. The 2D-PCIS and Raman analysis revealed that K3PO4 mostly promoted the dehydrogenation and polycondensation process of the aromatic rings in the char precursor, transforming the amorphous carbon structure of biochar into an ordered turbostratic microcrystalline structure. K3PO4 enhanced biochar stability mostly at medium-high temperatures (350 ~ 750℃) by stimulating the transformation of unstable structures of biochar to stable carbon-containing structures or by inhibiting the interaction of its active sites with oxidants through the mineralization process. A 20% phosphorus addition increased biochar's refractory index (R50) by roughly 11%, and it also boosted biochar's oxidation resistance (H2O2 or K2CrO4) efficiency, reducing carbon oxidation loss by up to 7.31%. However, at higher temperatures (> 750 ℃), the doping of phosphorus atoms into the carbon skeleton degraded the biochar structure's stability. The results of this study suggest that using exogenous phosphorus-containing additives is an efficient way to improve the stability of biochar. Highlights: K3PO4 promoted biochar precursor's dehydrogenation/polycondensation process to form fused-ring aromatic structures. K3PO4 increased recalcitrant carbon proportion and shielded biochar's active sites through the mineralization process. By adding 20 wt% of K3PO4, the thermal and chemical stability of biochar were enhanced by 11% and 7%, respectively [ABSTRACT FROM AUTHOR]

The growing emphasis on indoor air quality and public health is fuelling the need for efficient yet affordable air purification techniques. In this study, the influence of biochar particle size on its adsorption efficiency toward airborne pollutants was examined. Bark-derived biochar particles were treated by grinding or ball milling, and then, seven samples with different particle size groups were separated. Biochar particles were characterized by particle size, proximate, SEM, XRD, and physisorption analyses. For adsorption efficiency, two different pollutants were tested at variable initial concentrations. The physical composition and XRD patterns of the biochar with different particle sizes were comparable. The ball-milled sample was an exception in that it had higher ash content and additional XRD peaks signifying contamination of the sample. The porosity of biochar was greater in smaller particles. Ball milling increased the specific surface area and total pore volume by 102% and 48%, respectively. Biochar with finer particle size exhibited the highest adsorption potential towards formaldehyde and methanol among other samples. It should be emphasized that simple mechanical grinding is preferred for reducing biochar size to avoid the risk of eventual contamination, greater energy consumption, and slower processing related to ball milling. When a low concentration of pollutant was tested (1 ppm formaldehyde), the effect of particle size on the adsorption efficiency was more noticeable. However, the effect of particle size was less dominant when higher concentrations of pollutants were tested. Smaller biochar particles (<100 μm) are more favourable for indoor air remediation given their superior adsorption efficiency of volatile organic compounds occurring at low concentrations in the buildings. [ABSTRACT FROM AUTHOR]

The production of sludge-based biochar to recover phosphorus (P) from wastewater and reuse the recovered phosphorus as agricultural fertilizer is a preferred process. This article mainly studied the removal of phosphate (PO4-P) from aqueous solution by synthesizing sludge-based biochar (MgSBC-0.1) from anaerobic fermentation sludge treated with magnesium (Mg)-loading-modification, and compared it with unmodified sludge-based biochar (SBC). The physicochemical properties, adsorption efficiency, and adsorption mechanism of MgSBC-0.1 were studied. The results showed that the surface area of MgSBC-0.1 synthesized increased by 5.57 times. The material surface contained MgO, Mg(OH)2, and CaO nanoparticles. MgSBC-0.1 can effectively remove phosphate in the initial solution pH range of 3.00–7.00, with a fitted maximum phosphorus adsorption capacity of 379.52 mg·g-1. The adsorption conforms to the pseudo second-order kinetics model and Langmuir isotherm adsorption curve. The characterization of the adsorbed composite material revealed the contribution of phosphorus crystal deposition and electrostatic attraction to phosphorus absorption. [ABSTRACT FROM AUTHOR]

Biochars have received much attention as efficient adsorbents for water pollutants. Besides, the chemical treatment of biochars performed to increase the adsorption capacity usually causes secondary chemical pollution and increases the cost of the process. The biomass feedstock utilised in biochar preparation impacts significantly the surface properties and adsorption capacity. Thus, the need to prepare new biochars from new feedstock with potentially high uptake capacities. Herein, we prepared new biochar (POBC) from Platanus occidentalis waste leaves (POL), which was utilised for the ultrasonic-aided adsorption of bromophenol blue (BRB) and thiazolyl blue tetrazolium bromide (TTB). The FTIR, SEM, EDX, TGA, BET, pHpzc, and elemental characterisations of POBC revealed potent surface characteristics desirable for efficient dye adsorption. An increase in the surface area from 14.31 m2/g to 31.94 m2/g and the pore volume from 0.0214 cm3/g to 0.0326 cm3/g was obtained after the conversion of the POL to POBC. Besides, the SEM images of POBC revealed a highly porous surface structure of the adsorbent. The Freundlich and pseudo-second-order model presented the best fit to the isotherm and kinetics based on the high coefficient of determination (R2 > 0.9) and low sum square errors (SSE < 0.31). The heterogeneous surface nature of POBC was inferred from the independent-oriented site model. The monolayer adsorption capacity of 45.03 mg/g and 48.8 mg/g were obtained for BRB and TTB, respectively. Thermodynamics showed an endothermic, feasible, and random uptake, and POBC displayed efficient potentials to be reused. The obtained results revealed that novel POBC is an efficient low-cost biochar with high adsorption capacity for dyes. [ABSTRACT FROM AUTHOR]

Sandy and acidic soil conditions are the major factors limiting the production of some vegetable crops in acidic soils. This study aims to examine the effect of various amendments on the growth, yield and mineral nutrients uptake of stem amaranth. Two pot experiments were conducted separately in two generic soils. Six treatments viz. T0 = control (without amendment), T1= lime, T2 = lime + wetland bottom sediment, T3 = lime + vermicompost, T4 = lime + rice straw biochar (RSB) and T5 = RSB were used for both experiments following CRD with four replications. Results revealed that plant heights (45.96 and 50.33 cm) of amaranth grown in alluvial and hill soils, respectively, were the highest in T4 treatment. Similarly, treatment T4 showed the highest fresh (118.53 and 116.11 g pot−1, respectively) and dry biomasses (16.98 and 19.54 g pot−1, respectively) for both soils. For both soils, treatment T4 resulted better nutrient uptake of N, P, K, S, Zn, Fe and Mn by edible stem, while non-amended soil gave the lowest result at all parameters. Analytical values of post-harvest soils indicated that T4 and/or T5 treatments resulted in an improvement in soil pH, organic carbon, total N, exchangeable K and extractable P, S and Zn. Treatment T3 showed elevated concentrations of extractable soils Fe and Mn. The amendment RSB combined with lime can be preferably used in strong acidic soils for cultivation of stem amaranth. [ABSTRACT FROM AUTHOR]

Phaseolus vulgaris is one of the most widely consumed legumes across the globe. It is rich in protein, carbohydrates, fiber, bioactive compounds, and mineral contents. Occurrences of drought under changing climate have posed a challenge to the quality and quantity of the crop yield. Our study, taking Phaseolus vulgaris as a test legume, reports that as a soil amendment, biochar and farmyard manure mitigated drought-induced damage in the plant. The experiment was set up in a greenhouse with 1 m2 blocks together arranged in factorial randomized block design. Water withdrawal was done for 15 days in either vegetative or reproductive stage of the crop to simulate drought conditions. Biochar or Farmyard manure was applied at the rate of 10t ha−1 as soil amendment and each treatment was replicated thrice. Higher photosynthesis (up to 23% and 16%, respectively), leaf protein (41% and 30%, respectively), grain protein (4% and 19%, correspondingly), and in-vitro protein digestibility (60% and 254%, respectively) were noted under application of both the amendments. Grain quality in terms of protein content, in-vitro protein digestibility, and protein fractions of Phaseolus vulgaris was improved under drought due to the addition of biochar and farmyard manure. However, the application of those amendments at the rate of 10t ha−1, especially farmyard manure, had a negative impact on the antinutritional factor (phytic acid) and mineral bioavailability. Between the two amendments studied, farmyard manure proved to be more efficient in promoting the overall grain quality of P. vulgaris, but its inimical effects must be concorded. [ABSTRACT FROM AUTHOR]

Salinity is a major environmental problem that adversely affects plant growth by increasing soil osmotic pressure and disrupting plant nutrition. Using organic amendments is a viable tool for reducing physiological and morphological effects of excessive soil salinity on plants. To show the impacts of tea waste, compost and biochar on nutrient status and growth parameters of spinach (Spinacia oleracea L.) raised in salinity conditions, this study has employed factorial CRD with two treatments involving soil salinity (2.5 and 8 dS m−1) and organic materials (spent tea waste (STW), spent tea waste compost (STWC) and spent tea waste biochar (STWB)) at 0 and 3% w/w in three replications. As soil salinity increased from 2.5 to 8 dS m−1, fresh weight and dry matter production decreased by 31.5% and 30.4%, respectively. Phosphorous and potassium concentrations in plant tissue also decreased significantly due to the increase in salinity. Organic amendments (except STW) due to their physicochemical properties increased the nutrients uptake and growth parameters of the plant. Compared to other amendments, biochar reduced salinity effects on plant growth more effectively, which is possibly due to its high nutrient adsorbing and water holding capacity. In saline conditions, the highest potassium to sodium ratio belonged to the biochar treatment, which was 3.22 and 2.78 times greater than spent tea waste and compost, respectively. Therefore, it was preferred to change the spent tea waste into biochar before being used as soil amendment. [ABSTRACT FROM AUTHOR]

• Biochar ammoniacal nitrogen adsorption capacity was measured. • Nitric acid increased biochar capacity to reduce aerobic degradation ammonia losses. • Biochar ammoniacal nitrogen adsorption explains its capacity to reduce ammonia losses. • Biochar adsorption properties is related to its surface electrical charge. One of the technical barriers to the wider use of biochar in the composting practices is the lack of accurate quantification linking biochar properties to application outcomes. To address this issue, this paper investigates the use of ammonia nitrogen adsorption capacity by biochar as a predictor of ammonia emission during composting in the presence of biochar. With this in mind, this work investigated the use of ammonia nitrogen adsorption capacity of biochar when mixed with solid digestate, and the reduction in ammonia emissions resulting from the addition of biochar during aerobic degradation of solid digestate. A biochar synthesized at 900 °C, another synthesized at 450 °C, and two derivatives of the latter biochar, one chemically modified with nitric acid and the other with potassium hydroxide, were tested. This study concluded that the chemical characteristics of the biochar, including pH and oxygen/carbon atomic ratio, had a greater influence on the adsorption of ammonia nitrogen than physical attributes such as specific surface area. In this regard, nitric acid modification had superior performance compared to hydroxide potassium modification to increase biochar chemical attributes and reduce ammonia emissions when applied to aerobic degradation. Finally, a significant linear correlation (p-value < 0.05, r2 = 0.79) was found between biochar ammonia nitrogen adsorption capacity and ammonia emissions along composting, showing the potential of this variable as a predictive parameter. This study provides insights for future explorations aiming to develop predictive tests for biochar performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar amendment to the digestate-based bioponics improved plant yield. • Biochar adsorbed heavy metals and decreased their bioaccumulation in plants. • Noncancer and cancer risks were found from ingestion of the plants. • Biochar enhanced microbial communities, aiding metal stabilization in bioponics. • Biochar promoted genera in sludge and plant roots for efficient P and N recovery. Bioponics is a nutrient-recovery technology that transforms nutrient-rich organic waste into plant biomass/bioproducts. Integrating biochar with digestate from anaerobic wastewater treatment process can improve resource recovery while mitigating heavy metal contamination. The overarching goal of this study was to investigate the application of biochar in digestate-based bioponics, focusing on its efficacy in nutrient recovery and heavy metal removal, while also exploring the microbial community dynamics. In this study, biochar was applied at 50 % w/w with 500 g dry weight of digestate during two 28-day crop cycles (uncontrolled pH and pH 5.5) using white stem pak choi (Brassica rapa var. chinensis) as a model crop. The results showed that the digestate provided sufficient phosphorus and nitrogen, supporting plant growth. Biochar amendment improved plant yield and phosphate solubilization and reduced nitrogen loss, especially at the pH 5.5. Furthermore, biochar reduced the heavy metal accumulation in plants, while concentrating these metals in the residual sludge. However, owing to potential non-carcinogenic and carcinogenic health risks, it is still not recommended to directly consume plants cultivated in digestate-based bioponic systems. Additionally, biochar amendment exhibited pronounced impact on the microbial community, promoting microbes responsible for nutrient solubilization and cycling (e.g., Tetrasphaera , Herpetosiphon , Hyphomicrobium , and Pseudorhodoplanes) and heavy metal stabilization (e.g., Leptolinea , Fonticella , Romboutsia , and Desulfurispora) in both the residual sludge and plants. Overall, the addition of biochar enhanced the microbial community and facilitated the metal stabilization and the cycling of nutrients within both residual sludge and root systems, thereby improving the overall efficiency of the bioponics. [ABSTRACT FROM AUTHOR]

The presence of heavy metal ions in water environments has raised significant concerns, necessitating practical solutions for their complete removal. In this study, a combination of adsorption and electrocoagulation (ADS + EC) techniques was introduced as an efficient approach for removing high concentrations of nickel ions (Ni2+) from aqueous solutions, employing low-cost sunflower seed shell biochar (SSSB). The combined techniques demonstrated superior removal efficiency compared to individual methods. The synthesized SSSB was characterized using SEM, FT-IR, XRD, N2-adsorption–desorption isotherms, XPS, and TEM. Batch processes were optimized by investigating pH, adsorbent dosage, initial nickel concentration, electrode effects, and current density. An aluminum (Al) electrode electrocoagulated particles and removed residual Ni2+ after adsorption. Kinetic and isotherm models examined Ni2+ adsorption and electrocoagulation coupling with SSSB-based adsorbent. The results indicated that the kinetic data fit well with a pseudo-second-order model, while the experimental equilibrium adsorption data conformed to a Langmuir isotherm under optimized conditions. The maximum adsorption capacity of the activated sunflower seed shell was determined to be 44.247 mg.g−1. The highest nickel ion removal efficiency of 99.98% was observed at initial pH values of 6.0 for ADS and 4.0 for ADS/EC; initial Ni2+ concentrations of 30.0 mg/L and 1.5 g/L of SSSB; initial current densities of 0.59 mA/cm2 and 1.32 kWh/m3 were also found to be optimal. The mechanisms involved in the removal of Ni2+ from wastewater were also examined in this research. These findings suggest that the adsorption-assisted electrocoagulation technique has a remarkable capacity for the cost-effective removal of heavy metals from various wastewater sources. [ABSTRACT FROM AUTHOR]

To enhance the adsorption performance of municipal sludge biochar on Cd(II), modified sludge biochar was prepared by sodium hydroxide/magnesium chloride (NaOH/MgCl2) graded activation, and the Cd(II) adsorption performance on sludge biochar (BC), NaOH-activated sludge biochar (NBC) and NaOH/MgCl2 activated sludge biochar (NBC-Mg) was investigated. The results showed that NaOH/MgCl2 graded activation upgraded the surface structure and enhanced the graphitization of sludge biochar. The adsorption experiments indicated that the adsorption kinetic and adsorption isotherm for Cd(II) were in accordance with the pseudo second-order kinetic and Langmuir model. The adsorption capacity of NBC-Mg (143.49 mg/g) for Cd(II) was higher than that of BC (50.40 mg/g) and NBC (85.20 mg/g). The mechanism of Cd(II) adsorption included ion exchange, complexation, cation-π interaction, and mineral precipitation. After five regeneration, the removal efficiency of Cd(II) by NBC-Mg remained above 90%. This work indicated that sludge biochar prepared by multistage activation could be an effective material for Cd-containing wastewater treatment. [ABSTRACT FROM AUTHOR]

Recently, visible-light-driven photocatalysis attracts much concerns in the remediation of environmental organic pollutants. In this study, the cerium doped biochar was fabricated through the hydrothermal method, and served as an efficient photocatalyst towards rhodamine B degradation under visible light irradiation. Almost 100% of rhodamine B was removed by 2.0 g·L−1 cerium doped biochar after 60 min of visible light irradiation at pH 3, but only about 25.50% and 29.60% of rhodamine B was removed by cerium dioxide and biochar under identical conditions. The degradation process coincided well with the pseudo-first-order kinetic model, and the photodegradation rate constant of cerium doped biochar was 0.0485·min−1, which was respectively 97 and 44 times that of biochar (0.0005·min−1) and cerium dioxide (0.0011·min−1). According to the trapping experiments and electron spin resonance spectroscopy analysis, h+, O2−∙ and ∙OH all participated in the degradation of rhodamine B in the cerium doped biochar photocatalytic systems, and the function of h+ and ∙OH was dominated. Consequently, the biochar could not only be an excellent carrier for supporting cerium dioxide, but also greatly improved its photocatalytic activity. The band gap of cerium doped biochar was narrower than cerium dioxide, which could improve the separation and migration of photogenerated electron–hole pairs under visible-light excitation, thus ultimately enhanced the degradation of rhodamine B. This work provided a deeper understanding of the preparation of biochar-based photocatalyst and its application in the remediation of environmental organic pollution. [ABSTRACT FROM AUTHOR]

This study investigated the potential of biochar as a sustainable material for waste utilization and carbon sequestration in soil. Biochar was prepared from cow manure (CM) and applied to the soil. Biochar was processed by subjecting CM to various temperature ranges (400 [CMB400], 550 [CMB550], and 700 °C [CMB700]) under nitrogen gas (allowed to flow to restrict oxygen), with residence time set to 3 h. The characteristics of the biochar produced at each temperature were analyzed. The experiment was conducted for approximately 15 weeks with the laboratory temperature maintained between 24 and 26 °C. The growth rate of plants was obtained by measuring their length weekly, starting 4 weeks after crop establishment. CMB550 exhibited the highest specific surface area (117.57 m2 g−1) and well-distributed pore size; therefore, it was mixed with the soil at a specific ratio and put in pots for the planting of Salicornia herbacea L. (glasswort) in the laboratory. The results demonstrated that adding biochar to soil increased plant growth and that the biochar could store organic carbon. In addition, an investigation of heavy metals demonstrated that samples with biochar had lower heavy metal concentrations in glasswort than those without because of the potential of biochar to adsorb heavy metals. By interacting with heavy metal ions in soil solution, the reactive sites and functional groups on the surface of biochar immobilize them and lessen their potentially detrimental effects on plant growth. Overall, biochar has the potential to be a valuable resource for waste management and environmental improvement. [ABSTRACT FROM AUTHOR]

Nitrogen (N) is the primary element that limits crop growth, and improving the nitrogen uptake in crops is a key challenge in sustainable agricultural production. Arbuscular mycorrhizal fungi (AMF), as important symbiotic microbes associated with most plants, can facilitate nitrogen uptake by plants and reduce greenhouse gas emissions, meaning they can play an important role in the development of sustainable agriculture. However, the effects of biochar application on mediating AMF N absorption are not clear, especially regarding the functional genes related to the N cycle in soil. In this study, we conducted a pot experiment with two P application rates (−P and +P) to study the effects of biochar and AMF on the community of soil microorganisms and N-cycle genes using metagenomic methods. The N uptake of both the shoots and roots of maize was measured. It was observed that the N uptake in the maize shoots and roots was significantly increased when they were exposed to a combination of AMF and biochar. Under both the −P and +P application rates, the root weights of the AMF and biochar combined (AMBC) treatments increased significantly by 58.3% and 43.2%, respectively, compared with the control (CN) treatments. Furthermore, there were significant increases in the root lengths, of 78.43% and 53.09%, respectively, as well as increases in the superficial areas of 60.0% and 41.9%, respectively. The combination treatment significantly changed the soil microbe community structure and increased the abundances of Geobacter and Pseudomonas. In addition, the abundances of the N-cycle genes of each process were enhanced. Under the −P condition, the total abundances of the N-cycle genes increased significantly by 1.97–2.19 times in the AMBC treatment compared with the CN treatment. Overall, the results suggest that biochar and AMF can promote plant root growth and lead to changes in the soil microorganism structure, resulting in an increase in the abundances of N-cycle genes which, in turn, increase the N uptake in the shoots and roots of maize. This study provides a biological pathway to improve the efficiency of N utilization in soil and prevent environmental pollution in sustainable agricultural production. [ABSTRACT FROM AUTHOR]

Plants are often exposed to multiple stresses, including heavy metals (HM) and drought, which limit the plant growth and productivity. Though biochar or plant growth-promoting rhizobacteria (PGPR) have been widely used for alleviating HM or drought stress in plants, the study of the effects of combined treatment with biochar and PGPR under simultaneous HM and drought stress is limited. This study investigated individual and combined effects of groundnut shell biochar (GS-BC) and PGPR Bacillus pseudomycoides strain ARN7 on Zea mays growth, physiology, and HM accumulation, along with their impact on soil enzymes under HM (Ni and Zn), drought, or HM+drought stress. It was observed that even under HM+drought stress, Z. mays growth, total chlorophyll, proteins, phenolics, and relative water contents were increased in response to combined GS-BC and ARN7 treatment. Furthermore, the combined treatment positively influenced plant superoxide dismutase, ascorbate peroxidase, and catalase activities, while reducing electrolyte leakage and phenolics, malondialdehyde, and proline under HM, drought, or HM+drought stress. Interestingly, the combined GS-BC and ARN7 treatment decreased HM accumulation and the bioaccumulation factor in Z. mays, highlighting that the combined treatment is suitable for improving HM phytostabilization. Additionally, GS-BC increased soil enzymatic activities and ARN7 colonization irrespective of HM and drought stress. As far as we know, this study is the first to illustrate that combined biochar and PGPR treatment could lessen the adverse effects of both HM and drought, suggesting that such treatment can be used in water-deficient HM-contaminated areas to improve plant growth and reduce HM accumulation in plants. [ABSTRACT FROM AUTHOR]

The global issue of ecological ditches being poor in removing nitrogen and phosphorus under cold winter temperatures has been identified. This study introduced three types of biochar (reed, rice, and corn) into ecological ditch sediments via two application methods: rhizosphere and mixed addition. The purpose was to explore how these methods affect the removal of nitrogen and phosphorus, as well as their influences on microbial communities in sediments. The results indicated that the addition of biochar to ecological ditches significantly enhanced the removal of nitrogen and phosphorus. Among the three types of biochar, the mixed addition of corn biochar yielded the greatest results, achieving removal rates of 77.1% for total nitrogen (TN), 93.3% for NH4+-N, and 90.3% for total phosphorus (TP). The growth of Vallisneria natans was greatly improved by the mixed addition method, resulting in an average increase of 154%. This improvement was superior to the rhizosphere addition group, which led to a growth increase of 125%. In comparison, the control group (CK) showed a decrease of 4.8% in growth. Different methods of biochar addition resulted in changes in the physicochemical properties and stoichiometry of the plants. Microbial analyses showed that the addition of biochar reduced the diversity and abundance of the substrate microbial community. [ABSTRACT FROM AUTHOR]

This scientific study investigated the adsorption capabilities of biochar samples derived from municipal sewage sludge pellets. Sewage sludge was pyrolyzed at various temperatures (400, 500, and 600 °C), and the biochar's properties, including specific surface area, pore volume, and pore size distribution, were assessed. The results indicate that the sewage sludge biochar samples are mesoporous materials with significant potential for good adsorption performance. Despite showing a decrease in specific surface area compared to that achieved with pyrolysis at 400 °C, samples pyrolyzed at 600 °C demonstrated an increase in mesopore surface area, enhancing their adsorption potential. Two filtration experiments, conducted at a flow rate of 8 mL/min, revealed that the column containing sewage sludge pyrolyzed at 600 °C retained phosphorus the most effectively during the first and second experiments (with retention efficiencies of 87% and 78%, respectively). The study concludes that municipal sewage sludge biochar could be a promising material for the removal of phosphorus from wastewater and represents a viable solution for sustainable environmental development. [ABSTRACT FROM AUTHOR]

Sandy areas occupy a huge amount of land worldwide, but due to their characteristics, they are mostly low in fertility and low in organic matter. Sandy soils have coarse texture, high saturated hydraulic conductivity, low soil organic carbon, and poor aggregate stability and water retention capacity; therefore, it is necessary to add organic additives to them. The objective of this study was to assess the effect of particle size and application rate of biochar (BC) produced under different pyrolysis temperatures on the porosity P, available water content for plants AWC, saturated hydraulic conductivity Ks, and contact angle CA of sandy soil. The results show that an application of BC to sandy soil significantly increased AWC by 76–168%, CA by 252–489%, P by 6–11%, and significantly reduced Ks by 37–90%. Statistical analysis of the effect of three examined factors (BC application rate, particle size, and pyrolysis temperature) revealed that P, AWC, and Ks were affected by all three factors, while CA was affected only by BC application rate and particle size. The statistically significant interaction between the two factors was found for P (temperature × rate and size × rate), AWC (temperature × size), and Ks (size × rate). Statistically significant interaction among the three factors was not found for any hydrophysical parameter. The application of BC to amend sandy soils can be seen as a strategy to mitigate drought conditions and to reduce the amount of irrigation, saving water. Further investigations are needed with regard to the BC application under climate conditions with long hot and dry periods, which may promote soil water repellency. [ABSTRACT FROM AUTHOR]

This study explored the effectiveness of hardened epoxy containing pear cactus fiber and onion sheath biocarbon nanosheet. Mechanical, dielectric, and thermal properties of pear cactus epoxy composites containing varying volumes of biocarbon nanosheet are the focus of this investigation. For this study, biocarbon was extracted by pyrolysis from red onion peel. For 3 vol.% of biocarbon, tensile strength was up to 63%, and flexural strength was up to 44% higher than pure epoxy. The addition of reinforcements boosted the Izod impact toughness and hardness values by around 5 volume percent to roughly 94% and 92%, respectively. When biocarbon made up 5% of a material's volume, improvements in dielectric constant and loss were around 5.8 and 0.23, respectively. The inclusion of biocarbon increased the thermal conductivity to a high of 0.44 W/mK. These composites might be used as a shielding material because to their improved dielectric, mechanical, and thermal activities. [ABSTRACT FROM AUTHOR]

Biochar derived from kenaf, a fast-growing plant, was used as a adsorbent in this study to remove phenol from aqueous solutions. Kenaf-derived biochar (KDB) was prepared at various temperatures (300–750 °C) and the relationship between the phenol adsorption mechanism and physicochemical properties was investigated. The highest phenol adsorption by KDB was achieved at 750 °C, and KDB pyrolyzed at 750 °C (KDB-750) had the lowest O/C (0.11) and H/C (0.01) values as well as the highest specific surface area (116.74 m2/g). Phenol molecules could be adsorbed on the surface of KDB via hydrophobic attraction and π–π interaction. Kinetic studies revealed that the adsorption reached equilibrium at 48 h, and the adsorption process was well explained by the pseudo-second-order model. The maximum phenol adsorbed obtained from equilibrium adsorption experiments was 41.1 mg/g, which is comparable to that reported in the literature. The enthalpy and entropy changes during phenol adsorption by KDB-750 were 22.3 kJ/mol and 64.2 J/K‧mol, respectively. The amount of phenol adsorbed decreased gradually from 38.5 to 32.4 mg/g as the pH of the solution increased from 3 to 9, and it decreased sharply from 32.4 to 28.9 mg/g as the pH increased from 9 to 11. When 0 to 200 mM NaCl was added to the phenol solution, the adsorbed amount decreased from 38.1 to 29.5 mg/g. Moreover, for a KDB-750 dosage of 10 g/L, > 90% of the phenol was removed. Thus, KDB-750, which is a low-cost and abundant adsorbent, could potentially be used as an adsorbent to remove phenol effectively. [ABSTRACT FROM AUTHOR]

New generation hybrid metal matrix composites (HMMC) play an imperative role in innumerable applications and are unceasingly displacing commonly available materials because of their excellent properties like low weight, rust resistance and elevated strength. Growing industrial interest emerges in profound examinations and researchers in the area of machining of HMMC to reduce the price of manufacturing. Owing to this evolution, the mandate to attain wide-ranging efficiency as far as product output and tooling has been increased. Usage of mineral-based cutting oil spoils the environment and labours health during metal cutting. In this work, to study the machinability problems allied to the produced HMMC (TiO2 + biochar + Al-7075), end milling experiments were conducted by utilising diverse speed-feed combinations under minimum quantity lubrication (MQL) strategy and compared with dry and flood environments. Effect on surface roughness, flank wear, microstructure and chip morphology during milling of aluminium 7075 HMMC were investigated. Each exploratory trials were completely reliant on the L27 orthogonal array (OA). For diverse Vc, MQL declined the Ra by about 31.71–39.16% and 16–37.24% over dry and flood machining environments. Vegetable oil in MQL has the tendency to reduce the serration and decreases the grain size with the help of its lubrication/cooling (L/C) effect. Here, response surface methodology (RSM) was implemented to derive the ideal machining parameters. The ideal cutting condition in machining of produced HMMC by desirability analysis is Vc = 50 m/min, f = 0.08 mm/min and E = MQL. [ABSTRACT FROM AUTHOR]

In this study, an empirical model for the pyrolysis of major oil palm wastes (OPW) such as palm kernel shell (PKS), empty fruit bunches (EFB), and oil palm frond (OPF), and their blends is developed. Moreover, the techno-economic feasibility of the wastes is investigated to determine the type of waste that would be suitable for the commercialization of different types of products. According to the model results, the bio-oil dominates the pyrolysis process' product output, accounting for 59.21, 50.51, 56.60, and 55.65% of PKS, EFB, OPF, and their blend, respectively. Whereas biochar yield is 23.21, 23.1, 22.95, and 23.08%, gas yield is 17.57, 26.38, 20.44, and 21.27%. The findings demonstrate that the feedstocks under consideration are mostly suitable for producing bio-oil. According to the economic analysis, PKS-based pyrolysis has the highest capital expenses (CAPEX), while EFB-based pyrolysis has the lowest CAPEX of all tested feedstocks. Furthermore, PKS has the highest operating expenses (OPEX) due to its relatively higher market price as well as higher moisture content, which necessitates more energy input during the drying stage. Among the feedstocks, OPF has delivered the highest profit of USD 17 M/year, with a 22% return on investment (ROI). In terms of investment capital payback period, all OPW feedstocks demonstrated a reasonable period of 4–6 years. Bio-oil is the most valuable pyrolysis product, with the highest market value when compared to biochar and syngas. The established prediction model can be utilized as a solid reference for biomass pyrolysis modelling studies. Furthermore, the predicted values are reasonable enough to be used in industrial process design. [ABSTRACT FROM AUTHOR]

The synthesized biochars derived from sawdust (SD) SD ozone (SDO) biochar, purified SD (PSD) biochar, and sonicated SD (SSD) biochar, which was employed in the confiscation of methylene blue (MB) dye ion, were characterized employing "Brunauer–Emmett–Teller (BET), scanning electron microscope (SEM), Fourier Transform Infrared (FTIR), and Thermal gravimetrical analysis (TGA)." The impact of various factors, such as pH, biochar dosage, and initial concentration, on MB dye sequestration, was tested in this study. It was found that the biosorption of MB dye to the various biochars was dependent on the solution pH, with optimum confiscation of MB observed at pH 12 for all biochars. Pseudo-second-order (PSO), Freundlich (FRH)- (SDO and SSD biochars), and Langmuir (LNR)- (PSD biochar) models were used to best describe the biosorption process of MB dye to various biochars. Based on the LNR model fitting to the experimental data, the optimum sorption capacities obtained using SDO, SSD, and PSD biochars were 200, 526, and 769 mg/g, respectively. Electrostatic interaction and hydrogen bonding played an important role in the interaction mechanism between the various biochars and MB dye. Hence, these studied SDO, PSD, and SSD biochars prepared from cheap, easily accessible, biodegradable, and non-hazardous agro-waste materials can be effectively used for the removal, treatment, and management of MB dye as well as other industrial effluents before their disposal into the environment. [ABSTRACT FROM AUTHOR]