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Climate change mitigation technologies have been a focus in reducing atmospheric carbon levels for the past few years. One such mitigation technology is pyrolysis, where biomass feedstocks are combusted at elevated temperatures for varying durations to produce three main products: biochar, bio-oil, and biogas. While bio-oil and biogas are typically used to produce energy via further combustion, biochar can be used in several different applications. Furthermore, using forest harvest residues as a feedstock for biochar production helps use excess biomass from the forestry industry that was previously assumed unmarketable. In our study, we combined forest carbon analysis modelling with cradle-to-gate life cycle emissions to determine the greenhouse gas emissions of biochar produced from forest harvest residues. We examined three collection scenarios, spanning two harvesting methods in one forest management unit in northern Ontario, Canada. From our analysis, we observed immediate reductions (− 0.85 tCO2eq·tbiochar−1 in year 1) in CO2-equivalent emissions (CO2eq) when producing biochar from forest harvest residues that would have undergone controlled burning, without considering the end use of the biochar. For the forest harvest residues that would remain in-forest to decay over time, producing biochar would increase overall emissions by about 6 tCO2eq·tbiochar−1. Throughout the 100-year timeframe examined–in ascending order of cumulative emissions–scenario ranking was: full tree harvesting with slash pile burn < full tree harvesting with slash pile decay < cut-to-length/tree-length harvesting. Highlights: Cradle-to-gate life cycle analysis for biochar production was evaluated. Forest harvest collection methods influence overall life cycle emissions for biochar. Harvest residues that typically undergo controlled burning are an ideal feedstock. [ABSTRACT FROM AUTHOR]

Fe–Mn oxide modified biochar (FMBC) was produced to explore its potential for remediation of Hg–Cd contaminated paddy soils. The results showed that the application of FMBC decreased the contents of bioavailable Hg and Cd by 41.49–81.85% and 19.47–33.02% in contrast to CK, while the amount of labile organic carbon (C) fractions and C-pool management index (CPMI) was increased under BC and FMBC treated soils, indicating the enhancement of soil C storage and nutrient cycling function. Dry weight of different parts of Oryza sativa L. was enhanced after the addition of BC and FMBC, and the contents of Fe and Mn in root iron–manganese plaques (IMP) were 1.46–2.06 and 6.72–19.35 times higher than those of the control groups. Hg and Cd contents in brown rice under the FMBC treatments were significantly reduced by 18.32–71.16% and 59.52–72.11% compared with the control. FMBC addition altered the composition and metabolism function of soil bacterial communities, especially increasing the abundance of keystone phyla, including Firmicutes, Proteobacteria and Actinobacteria. Partial least squares path modelling (PLSPM) revealed that the contents of Na2S2O3–Hg, DTPA–Cd and IMP were the key indicators affecting Hg and Cd accumulation in rice grains. These results demonstrate the simultaneous value of FMBC in remediation of Hg and Cd combined pollution and restoring soil fertility and biological productivity. Highlights: FMBC effectively remediated Hg and Cd co-contaminated paddy soils. FMBC increased soil labile C fractions and C sequestration. FMBC improved the relative abundance of specific phyla and metabolism potential. PLSPM exhibited the main ways of reducing Hg and Cd accumulation in rice grains. [ABSTRACT FROM AUTHOR]

Biochar-based sulfidized nano-sized zero-valent iron (SNZVI/BC) can effectively immobilize cadmium (Cd) in contaminated paddy soils. However, the synergistic effects between biochar and SNZVI on Cd immobilization, as well as the underlying mechanisms remain unclear. Herein, a soil microcosm incubation experiment was performed to investigate the immobilization performance of SNZVI/BC towards Cd in the contaminated paddy soil. Results indicated that the addition of SNZVI/BC at a dosage of 3% significantly lessened the concentration of available Cd in the contaminated soil from 14.9 (without addition) to 9.9 mg kg−1 with an immobilization efficiency of 33.3%, indicating a synergistic effect. The sequential extraction results indicated that the proportion of the residual Cd in the contaminated soil increased from 8.1 to 10.3%, manifesting the transformation of the unstable Cd fractions to the steadier specie after application of SNZVI/BC. Also, the addition of SNZVI/BC increased soil pH, organic matter, and dissolved organic carbon, which significantly altered the bacterial community in the soil, enriching the relative abundances of functional microbes (e.g., Bacillus, Clostridium, and Desulfosporosinus). These functional microorganisms further facilitated the generation of ammonium, nitrate, and ferrous iron in the contaminated paddy soil, enhancing nutrients' availability. The direct interaction between SNZVI/BC and Cd2+, the altered soil physicochemical properties, and the responded bacterial community played important roles in Cd immobilization in the contaminated soil. Overall, the biochar-based SNZVI is a promising candidate for the effective immobilization of Cd and the improvement of nutrients' availability in the contaminated paddy soil. Highlights: Biochar-based sulfidized nano-sized zero-valent iron (SNZVI/BC) synergistically immobilized Cd in the contaminated soil. SNZVI/BC effectively enhanced nutrients' availability in the contaminated soil. Nitrate-, Iron-, and sulfate-reducing bacteria were enriched in the SNZVI/BC-treated soil. Precipitation and complexation played an important role in the immobilization of Cd. [ABSTRACT FROM AUTHOR]

Soil salinity is a significant challenge in agriculture, particularly in arid and semi-arid regions such as Pakistan, leading to soil degradation and reduced crop yields. The present study assessed the impact of different salinity levels (0, 25, and 50 mmol NaCl) and biochar treatments (control, wheat-straw biochar, rice-husk biochar, and sawdust biochar applied @ 1% w/w) on the germination and growth performance of wheat. Two experiments: a germination study and a pot experiment (grown up to maturity), were performed. The results showed that NaCl-stress negatively impacted the germination parameters, grain, and straw yield, and agronomic and soil parameters. Biochar treatments restored these parameters compared to control (no biochar), but the effects were inconsistent across NaCl levels. Among the different biochars, wheat-straw biochar performed better than rice-husk and sawdust-derived biochar regarding germination and agronomic parameters. Biochar application notably increased soil pHs and electrical conductivity (ECe). Imposing NaCl stress reduced K concentrations in the wheat shoot and grains with concomitant higher Na concentrations in both parts. Parameters like foliar chlorophyll content (a, b, and total), stomatal and sub-stomatal conductance, and transpiration rate were also positively influenced by biochar addition. The study confirmed that biochar, particularly wheat-straw biochar, effectively mitigated the adverse effects of soil salinity, enhancing both soil quality and wheat growth. The study highlighted that biochar application can minimize the negative effects of salinity stress on wheat. Specifically, the types and dosages of biochar have to be optimized for different salinity levels under field conditions. [ABSTRACT FROM AUTHOR]

The increasing demand for soilless media, sustainability issues with peatmoss, and increasing cost of peatmoss have prompted studies of more environmentally friendly and less expensive substitutes. Biochar, a lightweight black carbon material produced by the pyrolysis of biomass, has gained popularity as a soilless media supplement. The objective of this study was to evaluate Eastern red cedar (ERC) biochar as a supplement to soilless media for the production of chrysanthemum and ornamental kale. Treatments included ERC biochar produced at three different temperature ranges of 300 to 350 °C, 400 to 450 °C, and 500 to 550 °C that were applied at 25%, 50%, and 75% v/v plus a control (100% v/v of standard commercial mix). Additionally, ERC bark was applied at the same rate as biochar. The 300 to 350 °C and 400 to 450°C temperature ranges increased the bulk density of the media, whereas total porosity was greatest with just bark. Regarding the physical properties of the media, in general, the 75% v/v supplementation rate of ERC bark or biochar at any temperature increased air porosity but decreased the water holding capacity, except for the water holding capacity at 500 to 550 °C. As the biochar production temperature increased, so did the pH and electrical conductivity (EC), whereas volatile matter decreased. Plant height, width, shoot dry weight, root dry weight, number of flowers (chrysanthemum only), flower diameter, and water use efficiency were greatest with the 100% v/v soilless media for both species. In general, chrysanthemum plants grown with 25% v/v biochar supplementation or bark had similar height, width, and shoot dry weight at any temperature compared with those grown with the 100% v/v soilless media. For ornamental kale, the 25% v/v 400 to 450 °C biochar supplementation showed plant height and water use efficiency similar to those of the 100% v/v soilless media. In general, 25% ERC bark performed similar to 25% v/v and 50% v/v biochar at any temperature for plant width, shoot dry weight, root dry weight, water use efficiency, and root-to-shoot ratio. The media nutrient content and EC were greater with 100% v/v soilless media and a lower rate (25% v/v) of ERC bark and biochar than with higher rates. The higher levels of biochar were harmful and reduced the ornamental kale growth and quality. These results suggest that supplemented soilless media with lower rates (25% v/v) of ERC biochar could be recommended for chrysanthemum, but that less than 25% v/v may be necessary for ornamental kale. [ABSTRACT FROM AUTHOR]

Thermally active structures such as crude oil pipelines and high-power voltage cables are usually embedded within local soils for their substructural stability. Based on site requirements, soils are amended with synthetic cementitious materials to improve their strength. However, synthetic binders such as cementation, geo-polymerization, and bio-cementation undermine thermal insulation while improving strength. Moreover, commonly used synthetic binders such as cement and lime are extremely harmful to the geoenvironment due to their hyper-alkalinity and high carbon footprint. Therefore, this study proposes a novel backfill composite consisting of clay loam, biochar, and biopolymer for superior thermal insulation and strength characteristics. Local soil containing high clay content was chosen due to its low thermal conductivity and potential to form stable hydrogen bonding with the biopolymer. The clay loam is amended with 2.5% to 7.5% (w/w) biochar and 0.5% to 1.5% (w/w) of biopolymer and their various combinations. Out of nine soil–biochar–biopolymer composites devised in the current study, six composites exhibited superior strength and lowered thermal conductivity than the plain soil in both conditions, i.e., optimum moisture state and upon drying. The findings of this study establish the synergistic attributes of biopolymer and biochar amendment for developing a high-strength thermal-insulating soil composite. [ABSTRACT FROM AUTHOR]

Biochar, a black carbon material produced by high‐temperature, low‐oxygen pyrolysis of organic solids, can improve soil properties and realize carbon neutrality. However, how to effectively produce and apply biochar in the face of the complex soil environment and intractable widespread land degradation is still uncertain. This review is based on 1073 sets of data in 316 publications to address this issue. Firstly, the impact of different process parameters, namely feedstocks, pyrolysis temperature and activation on physicochemical properties of biochar are systematically summarized. Secondly, the effect of biochar on different soil degradation problems are reviewed from the perspective of the interaction between the physicochemical properties of biochar and soil characteristics. The "matching" of biochar properties, level of degradation and environmental factors can be used to design the desired biochar. Finally, future research should focus on biochar aging and costs and benefits of using biochar. The concept of "artificial intelligence designed biochar" is discussed to improve the degree of automation in biochar production and the predictability and suitability of its application for specific cases. [ABSTRACT FROM AUTHOR]

Biochar application is widely recognized as an effective approach for increasing soil organic carbon (SOC) and mitigating climate change in agroecosystems. However, the effects of biochar application on net accumulations and relative contributions of different SOC sources remain unclear. Here, we explored the effects of biochar application on plant‐derived (PDC) and microbial necromass C (MNC) in a 10‐year experimental rice–wheat rotation field receiving four different intensities of biochar application (0, 2.25, 11.5, and 22.5 t ha−1 for each crop season), using phospholipid fatty acids (PLFAs), lignin phenols and amino sugars as biomarkers of microbial biomass, PDC and MNC, respectively. Our results showed that biochar application increased SOC content and stock by 32.6%–203% and 26.4%–145%, respectively. Higher biochar application (11.5 and 22.5 t ha−1) increased soil pH, total nitrogen (TN), total phosphorus (TP), SOC/TN, and root biomass. In addition, higher biochar application enhanced bacterial, fungal, and total microbial biomass. Plant lignin phenols and MNC contents significantly increased, whereas their contributions to SOC significantly decreased with the increase in biochar application rates due to the disproportionate increase in PDC and MNC, and SOC. Fungal necromass had a greater contribution to SOC than bacterial necromass. The fungal/bacterial necromass decreased from 2.56 to 2.26 with increasing biochar application rates, because of the higher abundances of bacteria than that of fungi as indicated by PLFAs under higher biochar application rates. Random forest analyses revealed that pH, TP, and SOC/TN were the main factors controlling plant lignin and MNC accumulation. Structural equation modeling revealed that biochar application increased lignin phenols by stimulating root biomass, whereas enhanced MNC accumulation was primarily from increased microbial biomass and lignin phenols. Overall, our findings suggest that biochar application increases the accumulation of the two SOC sources but decreases their contributions to SOC in paddy soils. [ABSTRACT FROM AUTHOR]

Ensuring global food security under present and futuristic scenario of climate change accompanied by expanding population is of major concern worldwide. Researchers across the world are focusing on sustainable agronomic practices to combat climate change induced issues like desertification, reduction in crop yield, pest outbreaks, and reduction in soil health. Biochar has demonstrated positive effects on plant growth, development, fruit quality, carbon capture and sequestration. Studies indicate that biochar amendments to soil can enhance soil health, plant growth and development as well as help in combating abiotic stressors. Biochar has several properties that make it an attractive soil amendment, including high porosity, surface area, water-holding capacity, and the ability to increase soil microbiota, which in turn can promote nutrient uptake and reduce soil erosion. Environmentally, biochar's ability to degrade organic pollutant as well as sequester carbon makes it a very attractive addition to sustainable agriculture. Nonetheless, biochar has also been reported to have potential hazardous impacts on human health associated with possible leakage of toxic elements and particulate matter pollution. However, lack of exhaustive studies that detail all the major aspects of biochar application in agroecosystem impedes decision making on its overall usability in agriculture. There exists a need for comprehensive review that cover all the important aspects of biochar supplementation. This review provides a thorough overview of the multifaceted impacts of biochar, encompassing its positive effects on soil, plant growth, development and environment, while also exploring the limitations along with potential toxic effects associated with its application. [ABSTRACT FROM AUTHOR]

The response of soil microorganisms and plants in soil ecosystems to biochar is well recognised. However, biochars' impact on large soil animal, such as ants, is inadequately understood, with only limited studies focusing on the abundance and mortality rates of some specific ant species. In this study, soil physicochemical properties, and ant community diversity and functional characteristics were compared between experimental plots with and without biochar application. No significant differences in soil (soil physicochemical properties) or ants (ant community richness, species abundance, and morphological characteristics) were observed between the two plots before biochar application. However, the biochar-treated plot soil surface temperatures, pH, and soil water content were significantly higher after 48 weeks. Biochar application promoted Cardiocondyla nuda (by 426%) and Formica japonica abundance (by 93%), but decreased Solenopsis invicta invasive ant species richness (by 54%), consistent with the fact that changes in soil properties were more beneficial to the former two species. In addition, in biochar-treated plots, F. japonica and S. invicta generally showed larger body size (18% and 6.7%), larger eyes (2.7% and 4.0%), and longer femurs (6.3% and 7.9%), which enabled them to respond better to potential barriers, such as plants. Our results highlighted that, besides species abundance and community structure, certain ant functional morphological indicators were also informative in evaluating biochar ecological implications. Highlights: Biochar application enhanced soil temperature, pH, and water content. Ants showed larger body size, larger eyes, and longer femurs with biochar application. Biochar promoted ant richness by creating ant-preferred habitats. [ABSTRACT FROM AUTHOR]

While many studies have examined the role of biochar in carbon (C) accrual in short-term scale, few have explored the decadal scale influences of biochar on non-biochar C, e.g., native soil organic C (SOC) and added substrate. To address this knowledge gap, soils were collected from decade-old biochar field trials located in the United Kingdom (Cambisol) and China (Fluvisol), with each site having had three application rates (25–30, 50–60 and 75–100 Mg ha−1) of biochar plus an unamended Control, applied once in 2009. We assessed physicochemical and microbial properties associated with sucrose (representing the rhizodeposits) mineralization and the priming effect (PE) on native SOC. Here, we showed both soils amended with biochar at the middle application rate (50 Mg ha−1 biochar in Cambisol and 60 Mg ha−1 biochar in Fluvisol) resulted in greater substrate mineralization. The enhanced accessibility and availability of sucrose to microorganisms, particularly fast-growing bacterial genera like Arenimonas, Spingomonas, and Paenibacillus (r-strategists belonging to the Proteobacteria and Firmicutes phyla, respectively), can be attributed to the improved physicochemical properties of the soil, including pH, porosity, and pore connectivity, as revealed by synchrotron-based micro-CT. Random forest analysis also confirmed the contribution of the microbial diversity and physical properties such as porosity on sucrose mineralization. Biochar at the middle application rate, however, resulted in the lowest PE (0.3 and 0.4 mg of CO2-C g soil−1 in Cambisol and Fluvisol, respectively) after 53 days of incubation. This result might be associated with the fact that the biochar promoted large aggregates formation, which enclosed native SOC in soil macro-aggregates (2–0.25 mm). Our study revealed a diverging pattern between substrate mineralization and SOC priming linked to the biochar application rate. This suggests distinct mechanisms, biophysical and physicochemical, driving the mineralization of non-biochar carbon in a field where biochar was applied a decade before. Highlights: The application of biochar at a moderate rate (50–60 Mg ha−1) resulted in increased labile C mineralization and decreased priming of native SOC. Biochar amendments led to the reconfiguration of physicochemical properties, including pH, porosity, and the formation of aggregates. Modified microbial community structure towards more r-strategists caused greater sucrose mineralization. Biochar incorporation rate governed the C dynamics via (biophysical vs physicochemical mechanisms) in long-term biochar amended fields. [ABSTRACT FROM AUTHOR]

Biochar is widely used for sediment remediation owing to its excellent adsorption properties and low carbon footprint. However, the impacts of biochar capping on phosphorus (P) bioavailability and mobility in the sediment are little known. In this study, the P mobilization processes in sediments capped with biochar were investigated by combining advanced high-resolution sampling techniques and microbiome analysis. The results showed that biochar is a double-edged sword for the sediment P release, depending on the application dosage and the capping time. In the short term (30 days), 2-cm biochar capping decreased the release flux of soluble reactive phosphorus (SRP) by 73.1%, whereas the 1-cm biochar capping significantly increased the release flux of SRP by 51.0%. After aging of biochar (80 days), the resupply capacity of sediment P was improved, resulting in increases of more than 33.7% and 121.5% in the release fluxes of SRP in the 1-cm and 2-cm capping groups, respectively, compared to the control group. Chemisorption played a pivotal role in regulating the levels of SRP, particularly during the short-term capping period. And more biochar can provide more adsorption sites on P. The P mobilization increase could be attributed to P desorption from biochar after biochar aging. Furthermore, biochar capping intensified the microbial-mediated iron reduction and organic matter decomposition, which enhanced P mobility. Our study highlights the importance of biochar application dosage and the capping time in sediment remediation, providing a scientific basis for the optimization of biochar capping techniques. Highlights: Biochar capping caused a sudden increase in organic matter and P concentration. Aging biochar enhanced the bioavailability and release flux of P. Biochar capping enhanced the P mobility by altering the microbial community. [ABSTRACT FROM AUTHOR]

Crop residue-based biochar (CRB) has shown great potential for removing trace elements (TEs) from aquatic matrices. Despite the increasing interest in this area, no review has focused specifically on the efficacy of CRB for TEs removal in aquatic environments. This comprehensive review examines the global TEs water contamination status with an emphasis on their sources, compositional metrics for crop residue feedstock (proximate, ultimate, and lignocellulosic properties), and the potential use of CRB for TEs removal in aquatic media. It also evaluates the factors that affect the ability of CRB to remove TEs, such as feedstock type, production conditions, water pH, background electrolytes, water temperature, CRB/water ratio, and underlying pollutant sorption mechanisms. This review also discusses the practical applications of CRB in real water samples and engineering considerations for designing CRB with improved physicochemical properties, treatment efficiencies, and regeneration abilities. Additionally, the cost–benefit and economic assessment of CRB, challenges, and future research directions related to CRB are highlighted to promote research on this sustainable source of biochar. By elucidating the prospects of CRB as an adsorbent, this review emphasizes the need for continued research on its practical implications for environmentally relevant pollutant concentrations. Highlights: Crop residue-based biochar (CRB) emerged as a top-notch adsorbent for TEs in aquatic systems. The CRB adsorption potential depended on the experimental conditions. The application of CRB to real water samples highlights its potential on a larger scale. Engineer-designed CRB exhibits high treatment efficiencies and regeneration abilities. [ABSTRACT FROM AUTHOR]

In this study, a newly developed composite of biochar-poly(m-phenylenediamine) (BC-PmPD) exhibiting a distinct skeletal structure was synthesized for the purpose of extracting Cr(VI) from aqueous solutions. BC was employed as a supportive carrier onto which PmPD nanoparticles were uniformly affixed through in-situ polymerization and oxidation synthesis, both within and outside the layered configuration of BC. The structural stability and morphologies of BC-PmPD were assessed utilizing Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, thermogravimetric analysis, analysis of specific surface area and pore size, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction. In comparison to other modified BCs reported, BC-PmPD exhibited the highest Cr(VI) removal rate. Specifically, at 303 K, BC-PmPD achieved a maximum Cr(VI) removal capacity of 775 mg g−1, surpassing the capabilities of unmodified BC and PmPD by 10.4 and 2.13 times, respectively. Analyses involving XPS, FTIR, and density functional theory calculation confirmed that proton transfer happened between protonated amine (−NH2) functional group within the structure of BC-PmPD and HCrO4− before the formation of hydrogen bond. Subsequently, environmentally persistent free radicals facilitated the reduction of the adsorbed Cr(VI). Quantification of the functional groups indicated that the amino group was responsible for 93.0% of the Cr(VI) adsorption in BC-PmPD. BC-PmPD displayed potent adsorption and reduction capabilities, alongside notable stability, repeatability, and promising potential for application in the remediation for high concentrations of Cr(VI) in electroplating wastewater scenarios. Highlights: Novel 3D material was prepared and the removal rate of Cr(VI) on BC-PmPD was the highest as compared to reported BCs. The maximum adsorption amount of Cr(VI) on BC-PmPD was high up to 1034 mg g−1 at 323 K and −NH2 adsorbed 93.0% HCrO4–. DFT calculation confirmed proton transfer happened between protonated −NH2 and HCrO4− before the formation of H bond. [ABSTRACT FROM AUTHOR]

The present study assessed the effective use of biochar for the adsorption of two potent HAB toxins namely, Microcystin-LR (MCLR) and Saxitoxin (STX) through a combination of dosage, kinetic, equilibrium, initial pH, and competitive adsorption experiments. The adsorption results suggest that biochar has excellent capabilities for removing MCLR and STX, with STX reporting higher adsorption capacities (622.53–3507.46 µg/g). STX removal required a minimal dosage of 0.02 g/L, while MCLR removal needed 0.4 g/L for > 90%. Similarly, a shorter contact time was required for STX removal compared to MCLR for > 90% of toxin removed from water. Initial pH study revealed that for MCLR acidic conditions favored higher uptake while STX favored basic conditions. Kinetic studies revealed that the Elovich model to be most suitable for both toxins, while STX also showed suitable fittings for Pseudo-First Order and Pseudo-Second Order in individual toxin systems. Similarly, for the Elovich model the most suited kinetic model for both toxins in presence of each other. Isotherm studies confirmed the Langmuir–Freundlich model as the best fit for both toxins. These results suggest adsorption mechanisms including pore filling, hydrogen bonding, π–π interactions, hydrophobic interactions, electrostatic attraction, and dispersive interactions. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) is a biological process that occurs in the limited presence of oxygen. This process involves various difficulties during the operation, such as acidification and increased concentration of volatile fatty acids, which can inhibit methane production. Therefore, in this work, the impact of biochar on the co-digestion of untreated sludge and residual biomass under mesophilic conditions was studied. For the production of biochar, the gasification process was used at different temperatures: 759 °C (BL), 798 °C (BM), and 888 °C (BH). This biochar was added in concentrations of 0 g/L, 3.33 g/L, and 6.67 g/L at the beginning of the co-digestion process. The results showed that a concentration of 6.67 g/L with BH biochar increased the PBM by 18% compared to the control sample and reduced the chemical oxygen demand (COD) by 88%. In addition, there was a reduction of volatile fatty acids (VFA) of 42.75%. Furthermore, FTIR analysis demonstrated that biochar has appropriate functional groups for this process. These data suggest a good interaction of biochar with the mixture of sludge and municipal waste, indicating that biochar can improve the anaerobic co-digestion of untreated sludge and municipal waste. [ABSTRACT FROM AUTHOR]

In 2021, Mexico produced approximately 24.2 million tons of white corn, generating 3.6 million tons of corn cob residue. The final disposal of corn cob poses an environmental challenge in certain regions. This study examines the technical–economic feasibility and the greenhouse gas (GHG) mitigation potential of integrating a small-scale cogenerating gasifier fueled by corn cob into a nixtamalized corn flour manufacturing small and medium-sized enterprise (SME). This integration enables the generation of heat and electricity from the produced synthesis gas. Moreover, the process yields residual carbon, which can be used as biochar for soil restoration and removing atmospheric CO2. This option holds significance for the corn flour agroindustry in Mexico, as, in 2021, it consumed approximately 601.9 GWh of electrical energy and 938,279 GJ of thermal energy from LP Gas in its manufacturing processes to produce 2.6 million tons of nixtamalized white corn flour. These processes contributed to a total emission of 410,232 tons of CO2 into the atmosphere. The findings of this study demonstrate a cumulative reduction of 51.7% in CO2 emissions, resulting in economic benefits of USD 85,401 in 2017 for a case study SME that annually produces 1039 tons of corn flour. This study reveals the integration of a gasifier–cogenerator system fueled by corn cob as an economically viable low-carbon technology in the corn flour manufacturing industry. [ABSTRACT FROM AUTHOR]

A high-efficiency nickel-doped porous biochar (PCNi3) has been successfully synthesized from chestnut shell waste via a two-step chemical activation treatment with H3PO4. The influences of microstructure, surface morphology, elemental composition, surface functional groups, specific surface area, porosity, pore-size distribution, and chemical properties of the surface state on the removal of Cr (VI) from water were thoroughly investigated by using XRD, FESEM, FTIR, Raman, BET, and XPS testing methods, N2 adsorption, and XPS testing techniques respectively. The results indicate that the treatment of H3PO4 activation and nickel doping can effectively improve microstructure characteristics, thus promoting Cr (VI) adsorption capacity. The effects of initial solution pH, solution concentration, time, and temperature on remediation are revealed. The Cr (VI) uptake experiments imply that the adsorption curves of PCNi3 fit well with the Freundlich model, the pseudo-second-order kinetic model, and the Elovich model. The adsorption process of PCNi3 can be regarded as a spontaneous endothermic reaction limited by diffusion among particles and porosity. The adsorption mechanisms of PCNi3 are ion exchange, complexation, electrostatic adsorption, and coprecipitation with the assistance of surface active sites, porosity, Ni0 particles, and Ni7P3. With these advantages, PCNi3 reveals an extraordinary Cr (VI) removal capacity and a strong ability to reduce Cr (VI) to Cr (III). [ABSTRACT FROM AUTHOR]

The objective of this study is to develop a remediation technology for composited heavy metal-contaminated soil. Biochars (BC300, BC400, and BC500) derived from corn were combined with potassium dihydrogen phosphate (KH2PO4) to immobilize and remove heavy metal ions, including mercury (Hg2+), cadmium (Cd2+), and lead (Pb2+). The adsorption kinetics of metal ions in aqueous solutions with different concentrations was tested, and the fitting effects of the two models were compared. The findings demonstrate that the joint application of biochar and KH2PO4 could markedly enhance the immobilization efficacy of Pb2+, whereas the utilization of KH2PO4 on its own exhibited a more pronounced immobilization impact on Cd2+. Furthermore, the present study underscores the shortcomings of various remediation techniques that must be taken into account when addressing heavy metal-contaminated soils. It also emphasizes the value of comprehensive remediation techniques that integrate multiple remediation agents. This study offers a novel approach and methodology for addressing the intricate and evolving challenges posed by heavy metal contamination in soil. Its practical value and potential for application are significant. [ABSTRACT FROM AUTHOR]

Pea, member of the plant family Leguminosae, play a pivotal role in global food security as essential legumes. However, their production faces challenges stemming from the detrimental impacts of abiotic stressors, leading to a concerning decline in output. Salinity stress is one of the major factors that limiting the growth and productivity of pea. However, biochar amendment in soil has a potential role in alleviating the oxidative damage caused by salinity stress. The purpose of the study was to evaluate the potential role of biochar amendment in soil that may mitigate the adverse effect of salinity stress on pea. The treatments of this study were, (a) Pea varieties; (i) V1 = Meteor and V2 = Green Grass, Salinity Stress, (b) Control (0 mM) and (ii) Salinity (80 mM) (c) Biochar applications; (i) Control, (ii) 8 g/kg soil (56 g) and (iii) 16 g/kg soil (112 g). Salinity stress demonstrated a considerable reduction in morphological parameters as Shoot and root length decreased by (29% and 47%), fresh weight and dry weight of shoot and root by (85, 63%) and (49, 68%), as well as area of leaf reduced by (71%) among both varieties. Photosynthetic pigments (chlorophyll a, b, and carotenoid contents decreased under 80 mM salinity up to (41, 63, 55 and 76%) in both varieties as compared to control. Exposure of pea plants to salinity stress increased the oxidative damage by enhancing hydrogen peroxide and malondialdehyde content by (79 and 89%), while amendment of biochar reduced their activities as, (56% and 59%) in both varieties. The activities of catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) were increased by biochar applications under salinity stress as, (49, 59, and 86%) as well as non-enzymatic antioxidants as, anthocyanin and flavonoids improved by (112 and 67%). Organic osmolytes such as total soluble proteins, sugars, and glycine betaine were increased up to (57, 83, and 140%) by biochar amendment. Among uptake of mineral ions, shoot and root Na+ uptake was greater (144 and 73%) in saline-stressed plants as compared to control, while shoot and root Ca2+ and K+ were greater up to (175, 119%) and (77, 146%) in biochar-treated plants. Overall findings revealed that 16 g/kg soil (112 g) biochar was found to be effective in reducing salinity toxicity by causing reduction in reactive oxygen species and root and shoot Na+ ions uptake and improving growth, physiological and anti-oxidative activities in pea plants (Fig. 1). [ABSTRACT FROM AUTHOR]

Cd contamination, especially in farmland soil, can pose serious threats to human health as well as ecological security. Stabilization is an important strategy for agricultural soil Cd remediation. In this study, a Cd-resistant strain (Cupriavidus B-7) was isolated and loaded onto cow manure (CDB), rice straw (RSB) and pine wood biochar (PB) to investigate its effects on Cd stabilization by a 60-day pot experiment. Results indicated that the Cupriavidus B-7-loaded biochar (labelled as CDBB, PBB and RSBB) reduced the CaCl2-extractable Cd by 43.06–59.78%, which was significantly superior to individual applications of Cupriavidus B-7 and biochar. Likewise, the soil physicochemical properties, urease, catalase and phosphatase activities were improved, indicating improved soil health. Consequently, dry weights of pakchoi's shoot and root were increased by 938.9–1230.9% and 149.1–281.2%, respectively, by applying CDBB, PBB and RSBB. Meanwhile, the Cd accumulation in pakchoi shoots decreased by 38.06–50.75%. Notably, the RSBB exhibited an optimal performance on pakchoi growth promotion and Cd accumulation alleviation. The structural equation model indicated the synergistic effect on pakchoi growth promotion and Cd accumulation decreased between biochar and Cupriavidus B-7. Our research provides some new insights into the development of strategies for green and sustainable remediation of Cd-contaminated soil. Highlights: A Cd resistant Cupriavidus B-7 (B-7) was isolated from copper mining soil Biochar, B-7 and their conbination were used to remediate Cd polluted soil Biochar loaded B-7 outperformed individual treatments for Cd stabilization Biochar loaded B-7 alleivated the Cd uptake and promoted pakchoi growth [ABSTRACT FROM AUTHOR]

The use of saline water under drought conditions is critical for sustainable agricultural development in arid regions. Biochar is used as a soil amendment to enhance soil properties such as water-holding capacity and the source of nutrition elements of plants. Thus, the research was carried out to assess the impact of biochar treatment on the morphological and physiological characteristics and production of Solanum lycopersicum in greenhouses exposed to drought and saline stresses. The study was structured as a three-factorial in split-split-plot design. There were 16 treatments across three variables: (i) water quality, with freshwater and saline water, with electrical conductivities of 0.9 and 2.4 dS m− 1, respectively; (ii) irrigation level, with 40%, 60%, 80%, and 100% of total evapotranspiration (ETC); (iii) and biochar application, with the addition of biochar at a 3% dosage by (w/w) (BC3%), and a control (BC0%). The findings demonstrated that salt and water deficiency hurt physiological, morphological, and yield characteristics. Conversely, the biochar addition enhanced all characteristics. Growth-related parameters, such as plant height, stem diameter, leaf area, and dry and wet weight, and leaf gas exchange attributes, such rate of transpiration and photosynthesis, conductivity, as well as leaf relative water content were decreased by drought and salt stresses, especially when the irrigation was 60% ETc or 40% ETc. The biochar addition resulted in a substantial enhancement in vegetative growth-related parameters, physiological characteristics, efficiency of water use, yield, as well as reduced proline levels. Tomato yield enhanced by 4%, 16%, 8%, and 3% when irrigation with freshwater at different levels of water deficit (100% ETc, 80% ETc, 60% ETc, and 40% ETc) than control (BC0%). Overall, the use of biochar (3%) combined with freshwater shows the potential to enhance morpho-physiological characteristics, support the development of tomato plants, and improve yield with higher WUE in semi-arid and arid areas. [ABSTRACT FROM AUTHOR]

Environmental stressors such as drought, salinity, and heavy metals pose significant obstacles to achieving sustainable food security, necessitating the development of universally applicable and cost-effective solutions to ameliorate soil under stress. Biochar, an eco-friendly material to increase crop yield, has been researched for almost two decades and has great potential for global use in enhancing stress resistance. However, there hasn't been comprehensive research on the impact of biochar application on soil properties, and root and crop growth. To optimize and promote biochar application in agriculture under stress, this study integrates over 100 peer-reviewed articles to explain how biochar promotes crop growth by enhancing soil resistance to stress. Biochar's distinctive properties, such as porous structure, alkaline nature, enriched surface functional groups, and nutrient content, are responsible for the following soil environment benefits: improved soil physiochemical properties, increased nutrient cycling, and boosted microbial growth. Moreover, the research emphasizes that the enhanced stress resistance of biochar optimizes nutrient absorption, alleviates soil pollutants, and thereby enhances overall crop productivity. The study discusses the roles and mechanisms of biochar on soil under stress, as well as the challenges linked to the sustainable and economical implementation of biochar in extreme soil conditions. This review aims to provide a theoretical basis for the widespread and cost-effective use of biochar in improving soil under stresses, thereby enhancing soil health and food security. Highlights: Biochar's physicochemical properties help with stress resilience. Biochar's effect on multiple stresses mitigation promotes soil nutrients circulating. Biochar provides virtuous cycles for crop stress resistance and root growth. [ABSTRACT FROM AUTHOR]

Efficient energy storage systems are crucial for the optimal utilization of renewable energy. Sodium‐ion batteries (SIBs) are considered potential substitutes for next‐generation low‐cost energy storage systems due to the low cost and abundance of sodium resources. However, the industrialization of SIBs faces a great challenge in terms of the anode. Hard carbon could be a promising anode material due to its high capacity and low cost which originates from biomass. This study used pre‐treatment and template carbonization methods to extract a hard carbon material from a large amount of discarded biomass in bamboo powder waste. This material has a good initial Coulombic efficiency of 78.6 % and good cycling stability when applied to sodium ion batteries.Typically, the optimal hard carbon material is used as the anode to prepare sodium ion battery prototypes to demonstrate their potential applications. The anode exhibited excellent sodium storage performance with a reversible capacity of 303 mAh ⋅ g−1 at 1 C rate and good cycling performance, retaining 92.0 % of its capacity after 100 cycles. These results demonstrate that BPPHC is a promising candidate for anode material in sodium‐ion batteries. This work suggests that bamboo powder could be a low‐cost anode material for SIBs. [ABSTRACT FROM AUTHOR]

The use of biodegradable polymers as matrices in composites gives a wide range of applications, especially in niche areas. The assessment of the effect of the filler content on the change of mechanical properties makes it possible to optimize the composition for specific needs. Biochar was used as a filler in the studied composites with two different biodegradable blends as a matrix. Poly(1,4-butylene adipate-co-1,4-butylene terephthalate)/polylactide/biochar (PBAT/PLA/BC) and polylactide/poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate]/biochar (PLA/P(3HB-co-4HB)/BC) composites with 0, 10, 15, 20 and 30 wt% of biochar underwent mechanical tests. The test results revealed a change in the properties of the composites related to the filler content. The results of the tensile test showed that increasing the biochar content increased the tensile modulus values by up to 100% for composites with 30 wt% of biochar, compared to unfilled matrices, and decreased the elongation associated with the breaking of PBAT/PLA and PLA/P(3HB-co-4HB) matrix composites. The elongation values at break of PBAT/PLA and PLA/(3HB-co-4HB) composites with 30 wt% biochar were reduced by 50% and 65%, respectively, compared to the unfilled matrices. PLA/P(3HB-co-4HB) matrix composites, in contrast to PBAT/PLA/BC, showed a decrease in tensile strength with the increases in filler content from 35.6 MPa for unfilled matrix to 27.1 MPa for PLA/P(3HB-co-4HB)/BC30 composites. An increase in filler content increased the brittleness of the composites regardless of the matrix used, as determined under the Charpy impact-test. This phenomenon was observed for all tested PLA/P(3HB-co-4HB) composites, for which the impact strength decreased from 4.47 kJ/m2 for the matrix to 1.61 kJ/m2 for the composite containing 30 wt% biochar. PBAT/PLA-based composites with 10 wt% of biochar showed slightly lower impact strength compared to the unfilled matrix, but composites with 30 wt% biochar showed 30% lower impact strength than PBAT/PLA. The complex viscosity value increased with increased filler content. For all composites tested on both polyester matrices, the viscosity decreased with increasing angular frequency. [ABSTRACT FROM AUTHOR]

This document discusses the importance of removing heavy metals from water sources due to their increased concentrations from industrial activities. The focus is on adsorption as an effective method for removing pollutants from contaminated streams using various adsorbents. The document highlights several research papers that explore different materials and technologies for heavy metal removal, including the use of yeast cells, magnetic biocomposites, cherry pit biochar, alkali-modified sawdust, nano-biocomposites, calcined mussel shells, mineral-organic hybrid adsorbents, and natural bentonites. These studies demonstrate the potential of these materials for efficient and cost-effective heavy metal removal from water sources. [Extracted from the article]

Apple replant disease (ARD) negatively affects plant growth and reduces yields in replanted orchards. In this study, biochar was applied to apple replant soil with Fusarium oxysporum. Our aim was to investigate whether biochar could promote plant growth and alleviate apple replant disease by reducing the growth of harmful soil microorganisms, changing soil microbial community structure and improving the soil environment. This experiment included five treatments: apple replant soil (CK), methyl bromide fumigation apple replant soil (FM), replant soil with biochar addition (2%), replant soil with F. oxysporum spore solution (8 × 107 spores $ mL-1), and replant soil with biochar and F. oxysporum spore solution addition. Seedling biomass, the activity of antioxidant enzymes in the leaves and roots, and soil environmental variables were measured. Microbial community composition and community structure were analyzed using 16S rDNA and ITS2 gene sequencing. Biochar significantly reduced the abundance of F. oxysporum and increased soil microbial diversity and richness. Biochar also increased the soil enzyme activities (urease, invertase, neutral phosphatase, and catalase), the biomass (plant height, fresh weight, dry weight) and the activity of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase). The root indexes of apple seedlings was also increased in replant soil by biochar. In sum, biochar promoted the growth of plants, improved the replant soil environment, and alleviated apple replant disease. [ABSTRACT FROM AUTHOR]

The global agriculture industry is facing never before faced issues in the form of soil degradation, water scarcity, rising greenhouse gas emissions, and climate change. Among the possible remedies, applying biochar to the soil has drawn interest as a viable strategy. Although a great deal of literature has been written about the benefits and drawbacks of applying biochar initially, there is still a significant amount of research on the effects of using biochar repeatedly. This study seeks to address this gap by examining the varied effects of both the initial application (at rates of 0 t.ha−1, 10 t.ha−1, and 20 t.ha−1) and the reapplication of biochar (at rates of 0, 10, and 20 t.ha−1), especially when combined with different levels of nitrogen fertilizer (0, 108, and 162 kg.ha−1). The investigation focuses on soil properties and CO2 emissions from Haplic Luvisol in the temperate climate zone (Slovakia). The results showed that biochar generally improved soil properties, such as soil pH (KCl) (p <0.05), shifting it from acidic towards moderately acidic, and generally led to a decrease in ammonium (NH4+) and nitrate (NO3-) content. The second level of fertilization, combined with different biochar treatments, yielded the most efficient results in physical properties such as soil temperature, bulk density (BD), and soil water content (SWC) compared to control treatments without biochar. Biochar application contributed to the reduction of both average daily CO2 emissions and cumulative CO2 emissions during the study period (April – October) in 2022 compared to the control without biochar application. [ABSTRACT FROM AUTHOR]

Research on wastewater treatment processes in Maluti-a-Phofung Municipality (South Africa) has revealed that substandard wastewater management in this region contributes to terrestrial and aquatic pollution. Because this pollution poses a threat to the environment, there is a pressing need to reduce the environmental impact of poorly managed sewage sludge in the region. Biochar has been regarded as a cost-effective way of reducing chemical toxicity in terrestrial environments. In the present study, we aimed to investigate the effectiveness of biochar in the remediation of the toxicity of sewage sludge using the earthworm Eisenia fetida. Sewage sludge was collected from a local wastewater treatment plant and E. fetida were exposed to 0, 25, 50, and 100% non-amended and 10% biochar-amended sludge. After 28 days, survival, biomass and reproduction were assessed. Separately, in clean artificial soil, E. fetida was exposed to 5, 10 and 15% biochar amendment for 96 hours to determine if biochar amendment alone could be harmful to E. fetida. The results showed no significant differences in all parameters between the worms exposed to non-amended sludge and 10% biochar-amended sludge. Assessment of acetylcholinesterase and catalase activities in the earthworms that were exposed to biochar via clean soil revealed that 10% and 15% biochar amendment rates caused the worms to experience significant levels of neurotoxic and oxidative stress (p < 0.05). These findings reveal that biochar alone is likely to have adverse effects on soil organisms, and amendment rates higher or equal to 10% are not suitable to alleviate the toxic effects of sewage sludge. Significance: This study can be used as a reference in the usage of biochar as a toxicity remediator. Different biochar rates (≥ 10%) can have different effects on soil-dwelling organisms. Policymakers can use this study when constructing laws regarding the disposal of sewage sludge by wastewater treatment plants. [ABSTRACT FROM AUTHOR]

Environmental restoration and sustainable energy solutions require effective management and utilization of agricultural crop residues to reduce greenhouse gas emissions. Biowastes are a valuable resource that can be converted into biofuels and their byproducts, solving the energy crisis and reducing environmental impact. In this study, teff husk, primarily generated in Ethiopia during the production of teff within the agro-industrial sector, is used as a feedstock for slow pyrolysis. Ethiopia generates an estimated annual production of over 1.75 million tons of teff husk, a significant portion of which is incinerated, resulting in significant pollution of the environment. This study focuses on assessing teff husk as a potential material for slow pyrolysis, a crucial stage in biochar production, to tap into its biochar-producing potential. To identify the composition of biomass, the teff husk underwent an initial analysis using thermogravimetry. The significant presence of fixed carbon indicates that teff husk is a viable candidate for pyrolytic conversion into biochar particles. The process of slow pyrolysis took place at three temperatures—specifically, 400, 450, and 500 °C. The maximum biochar yield was achieved by optimizing slow pyrolysis parameters including reaction time, temperature, and heating rate. The optimized reaction time, temperature, and heating rate of 120 min, 400 °C, and 4.2 °C/min, respectively, resulted in the highest biochar yield of 43.4 wt.%. Furthermore, biochar's physicochemical, SEM-EDX, FTIR, and TGA characterization were performed. As the temperature of biochar increases, its carbon content and thermal stability increases as well. Unlike fuel recovery, the results suggest that teff-husk can be used as a feedstock for biochar production. [ABSTRACT FROM AUTHOR]

This work aimed to describe the adsorption behavior of Congo red (CR) onto activated biochar material prepared from Haematoxylum campechianum waste (ABHC). The carbon precursor was soaked with phosphoric acid, followed by pyrolysis to convert the precursor into activated biochar. The surface morphology of the adsorbent (before and after dye adsorption) was characterized by scanning electron microscopy (SEM/EDS), BET method, X-ray powder diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) and, lastly, pHpzc was also determined. Batch studies were carried out in the following intervals of pH = 4–10, temperature = 300.15–330.15 K, the dose of adsorbent = 1–10 g/L, and isotherms evaluated the adsorption process to determine the maximum adsorption capacity (Qmax, mg/g). Kinetic studies were performed starting from two different initial concentrations (25 and 50 mg/L) and at a maximum contact time of 48 h. The reusability potential of activated biochar was evaluated by adsorption–desorption cycles. The maximum adsorption capacity obtained with the Langmuir adsorption isotherm model was 114.8 mg/g at 300.15 K, pH = 5.4, and a dose of activated biochar of 1.0 g/L. This study also highlights the application of advanced machine learning techniques to optimize a chemical removal process. Leveraging a comprehensive dataset, a Gradient Boosting regression model was developed and fine-tuned using Bayesian optimization within a Python programming environment. The optimization algorithm efficiently navigated the input space to maximize the removal percentage, resulting in a predicted efficiency of approximately 90.47% under optimal conditions. These findings offer promising insights for enhancing efficiency in similar removal processes, showcasing the potential of machine learning in process optimization and environmental remediation. [ABSTRACT FROM AUTHOR]

Due to a large number of harmful chemicals flowing into the water source in production and life, the water quality deteriorates, and the use value of water is reduced or lost. Biochar has a strong physical adsorption effect, but it can only separate pollutants from water and cannot eliminate pollutants fundamentally. Photocatalytic degradation technology using photocatalysts uses chemical methods to degrade or mineralize organic pollutants, but it is difficult to recover and reuse. Woody biomass has the advantages of huge reserves, convenient access and a low price. Processing woody biomass into biochar and then combining it with photocatalysts has played a complementary role. In this paper, the shortcomings of a photocatalyst and biochar in water treatment are introduced, respectively, and the advantages of a woody biochar-based photocatalyst made by combining them are summarized. The preparation and assembly methods of the woody biochar-based photocatalyst starting from the preparation of biochar are listed, and the water treatment efficiency of the woody biochar-based photocatalyst using different photocatalysts is listed. Finally, the future development of the woody biochar-based photocatalyst is summarized and prospected. [ABSTRACT FROM AUTHOR]

In this study, TiO2/P, K-containing grapefruit peel biochar (TiO2/P, K-PC) composites were synthesized in situ biomimetically using grapefruit peel as the bio-template and carbon source and tetrabutyl titanate as the titanium source. This was achieved using the two-step rotary impregnation–calcination method. Adjusting the calcination temperature of the sample in an air atmosphere could regulate the mass ratio of TiO2 to carbon. The prepared samples were subjected to an analysis of their compositions, structures, morphologies, and properties. It demonstrated that the prepared samples were complexes of anatase TiO2 and P, K-containing carbon, with the presence of graphitic carbon. They possessed a unique morphological structure with abundant pores and a large surface area. The grapefruit peel powder played a crucial role in the induction and assembly of TiO2/P, K-PC composites. The sample PCT-400-550 had the best photocatalytic activity, with the degradation rate of RhB, MO, and MB dye solutions reaching more than 99% within 30 min, with satisfactory cyclic stability. The outstanding photocatalytic activity can be credited to its unique morphology and the efficient collaboration between TiO2 and P, K-containing biochar. [ABSTRACT FROM AUTHOR]

One-step carbonization was explored to prepare biochar using the residue of a traditional Chinese herbal medicine, Atropa belladonna L. (ABL), as the raw material. The resulting biochar, known as ABLB4, was evaluated for its potential as a sustainable material for norfloxacin (NOR) adsorption in water. Subsequently, a comprehensive analysis of adsorption isotherms, kinetics, and thermodynamics was conducted through batch adsorption experiments. The maximum calculated NOR adsorption capacity was 252.0 mg/g at 298 K, and the spontaneous and exothermic adsorption of NOR on ABLB4 could be better suited to a pseudo-first-order kinetic model and Langmuir model. The adsorption process observed is influenced by pore diffusion, π–π interaction, electrostatic interaction, and hydrogen bonding between ABLB4 and NOR molecules. Moreover, the utilization of response surface modeling (RSM) facilitated the optimization of the removal efficiency of NOR, yielding a maximum removal rate of 97.4% at a temperature of 304.8 K, an initial concentration of 67.1 mg/L, and a pH of 7.4. Furthermore, the biochar demonstrated favorable economic advantages, with a payback of 852.5 USD/t. More importantly, even after undergoing five cycles, ABLB4 exhibited a consistently high NOR removal rate, indicating its significant potential for application in NOR adsorption. [ABSTRACT FROM AUTHOR]

This study investigated the impacts of biochar addition on N conversion, humification, and bacterial community during Flammulina velutipes waste composting. The mixture of chicken manure and Flammulina velutipes waste was 4:6 (dry weight basis). The biochar was added into the mixture and mixed thoroughly at ratios of 0, 2.5, 5, and 7.5% (w/w) and labeled as CK, T1, T2, and T3, respectively. The results showed that the biochar treatment significantly improved the compost maturity by increasing humic substances and the conversion of NH4+-N to NO3−-N. With the increase in biochar supplemental level, the abundance, diversity, and uniformity of the microbial community were improved. The dominant taxa were Firmicutes, Bacteroidota, Actinobacteriota, Proteobacteria, and Gemmatimonadota, especially the Firmicutes and Bacteroidota. Biochar addition facilitated the proliferation of thermophilic bacteria such as Bacillus, Actinobacteriota, Parapedobacter, and Sphingobacterium, leading to enhanced organic decomposition to increase humus. The findings of this study highlighted the positive effects of biochar addition on the composting mixture of chicken manure and Flammulina velutipes waste. These results can help to produce high-quality biochar composting products by balancing organic decomposition and humification based on the bacterial community. [ABSTRACT FROM AUTHOR]

Aminopyralid (2-pyridine carboxylic acid, 4-amino-3, 6-dichloro-2-pyridine carboxylic acid) is an auxin herbicide that has been used widely to control broadleaf weeds in pasture and hay fields. With no post-application withdrawal time, aminopyralid absorbed into forage material can contaminate compost feed stocks such as hay, grass bedding material, and manure. Composts derived from such feed stocks raises concerns about after-effect injuries to sensitive crops by residual aminopyralids. Biochar (BC) additive may affect the composting process and immobilizes organic pollutants. This study examined the effect of composting dairy manure/sawdust 1:1 mixture containing 10 ppb (wet) of aminopyralid with 0%, 2%, 4%, and 10% (w/w) BC levels on chemical and biological characteristics of compost, residual aminopyralid concentration, and intensity of plant injury to tomato (Lycopersicon esculentum L.) plants after composting in 140 L plastic rotary drum reactors for two 6-month cycles. Biochar addition decreased organic matter degradation and intensified reduction in residual aminopyralid levels in a dose-dependent manner. Composting with BC concentrated more N, P, and K, caused mild plant injuries, and increased the above ground biomass compared to the no BC incorporation. Addition of BC for composting aminopyralid-contaminated dairy manure can increase the phyto safety level of compost while enhancing the key fertilizer values. [ABSTRACT FROM AUTHOR]

This study investigates the growth dynamics and heavy metal immobilization in Sudan grass cultivated on substrates composed of electrolytic manganese residue (EMR), phosphogypsum, and chili straw biochar. Pot experiments revealed that a substrate with phosphogypsum constituting 75% of the mix hinders Sudan grass seed germination. Compared with sole EMR utilization, the composite substrates notably enhanced plant growth, evidenced by increases in plant height and fresh weight. The integration of these substrates led to a significant elevation in total chlorophyll content (up to 54.39%) and a reduction in malondialdehyde (MDA) levels (up to 21.66%), indicating improved photosynthetic activity and lower oxidative stress. The addition of biochar reduced the content of Zn, Cd, and Mn in the roots of Sudan grass by up to 25.92%, 20.00%, and 43.17%, respectively; and reduced the content of Pb, Mn, and Cr in the shoot by up to 33.72%, 17.53%, and 26.32%, respectively. Fuzzy membership function analysis identified the optimal substrate composition as 75% EMR and 25% phosphogypsum, with 5% chili straw biochar, based on overall performance metrics. This study adopts the concept of "to treat waste with waste". The approach is to fully consider the fertility characteristics of EMR, phosphogypsum, and biochar, underscoring the potential for utilizing waste-derived materials in cultivating Sudan grass and offering a sustainable approach to plant growth and heavy metal management. [ABSTRACT FROM AUTHOR]

To improve nitrogen use efficiency (NUE) during rice cultivation, it is essential to comprehend the morphological and physiological traits of rice roots. However, in high-fertility black soil regions of Northeast China, the effects of combining biochar application with water-saving irrigation (WSI) conditions on rice root development and nitrogen utilization are still unknown. To address this knowledge gap, a combination of field experiments and 15N tracer micro-area investigations was conducted in this study. Four treatments were implemented: (i) controlled irrigation without biochar application (CB0); (ii) controlled irrigation with 2.5 t ha−1 biochar application (CB1); (iii) controlled irrigation with 12.5 t ha−1 biochar application (CB2); and (iv) controlled irrigation with 25 t ha–1 biochar application (CB3). Flooded irrigation conditions without biochar treatment (FB0) were used as the control. The primary objective of this research was to identify the mechanisms by which combined WSI conditions and biochar application affect rice root development and nitrogen utilization. Biochar application enhanced rice root morphological and physiological characteristics. Optimal biochar application increased the longest root length (RL), root volume (RV), root fresh weight (RFW), root active absorption area, root bleeding intensity, and root activity (RA) of rice while also optimizing the root–shoot ratio and facilitating nitrogen absorption by roots. These changes in root morphological and physiological characteristics facilitated the absorption of fertilizer-15N and soil nitrogen by rice roots, ultimately leading to improvements in rice yields and NUEs. Notably, the rice yields, NUE, nitrogen agronomic efficiency (NAE), and nitrogen partial factor productivity (NPFP) of CB2 plants were 16.45%, 39.42%, 24.48%, and 16.45% higher than those of FB0 plants, respectively. These results highlight the effectiveness of biochar application as a strategy to ensure food security and enhance NUE under WSI conditions. Furthermore, this study suggests that the recommended optimal application amount of biochar for the black soil area of Northeast China is 12.5 t ha−1. [ABSTRACT FROM AUTHOR]

Simple Summary: To find improved solutions for controlling cadmium pollution in agricultural soil, in situ field experiments were conducted to evaluate the impact of physical measures, phosphate fertilizer application, and soil conditioners on lettuce growth and cadmium absorption. The results revealed that deep plowing and soil covering significantly lowered the cadmium concentration in lettuce. While the application of phosphate fertilizer raised the cadmium concentration in lettuce, the use of diammonium phosphate and calcium magnesium phosphate fertilizer showed a positive correlation with the cadmium concentration, whereas calcium superphosphate displayed a negative correlation. Additionally, upon the application of biochar, attapulgite, and nano-hydroxyapatite, the cadmium concentration in lettuce initially increased with the rising amount of application, but subsequently decreased at higher doses. In conclusion, physical measures are evidently effective in preventing and controlling cadmium pollution. However, the application of phosphate fertilizer can exacerbate cadmium pollution in farmland soil. Soil conditioners, on the other hand, are only effective when used at higher application levels. The findings of this study are crucial for guiding practical cadmium pollution control measures in the field. This study aimed to evaluate the effects of physical measures and the applications of phosphorus fertilizer and soil conditioner on the growth of lettuce (Lactuca sativa) and its uptake of cadmium (Cd). In a solar greenhouse that contained soil enriched with cadmium (Cd) (1.75 ± 0.41 mg/kg) with lettuce used as a test plant, field experimental methods were utilized to explore the influence of physical measures, such as deep plowing and soil covering, and the applications of phosphorus fertilizer, including diammonium phosphate (DAP), calcium magnesium phosphate (CMP), and calcium superphosphate (SSP), and soil conditioners, such as biochar, attapulgite clay, and nano-hydroxyapatite, on the uptake of Cd in lettuce. The results indicated that the concentrations of Cd in the aboveground parts of lettuce were 1.49 ± 0.45, 1.26 ± 0.02, 1.00 ± 0.21, and 0.24 ± 0.13 mg/kg when the soil was plowed 30, 40, and 50 cm deep, respectively, and when the soil was covered with 15 cm, this resulted in reductions of 27.5%, 38.3%, 51.4%, and 88.4%, respectively, compared with the control treatment that entailed plowing to 15 cm. When 75, 150, and 225 kg/ha of phosphorus pentoxide (P2O5) were applied compared with the lack of application, the contents of Cd in the aboveground parts of lettuce increased by 2.0%, 54.5%, and 73.7%, respectively, when DAP was applied; by 52.5%, 48.5%, and 8.1%, respectively, when CMP was applied; and by 13.1%, 61.6%, and 90.9%, respectively, when SSP was applied. When the amounts of biochar applied were 0, 2, 4, 6, 8, 10, and 12 t/ha, the contents of Cd in the aboveground parts of lettuce were 1.36 ± 0.27, 1.47 ± 0.56, 1.80 ± 0.73, 1.96 ± 0.12, 1.89 ± 0.52, 1.44 ± 0.30, and 1.10 ± 0.27 mg/kg, respectively. Under concentrations of 0, 40, 80, 120, 160, and 200 kg/ha, the application of nano-hydroxyapatite resulted in Cd contents of 1.34 ± 0.56, 1.47 ± 0.10, 1.60 ± 0.44, 1.70 ± 0.21, 1.31 ± 0.09, and 1.51 ± 0.34 mg/kg, respectively. The concentrations of Cd in the aboveground parts of lettuce treated with attapulgite clay were 1.44 ± 0.48, 1.88 ± 0.67, 2.10 ± 0.80, 2.24 ± 0.75, 1.78 ± 0.41, and 1.88 ± 0.48 mg/kg, respectively. In summary, under the conditions in this study, deep plowing and soil covering measures can reduce the concentration of Cd in the aboveground parts of lettuce. The application of phosphorus fertilizer increased the concentration of Cd in the aboveground parts of lettuce. The application of higher amounts of DAP and SSP led to greater concentrations of Cd in the aboveground parts of lettuce. The application of higher amounts of CMP caused a lower concentration of Cd in the aboveground parts of lettuce. When biochar, attapulgite clay, and nano-hydroxyapatite were applied, the concentration of Cd in the aboveground parts of lettuce increased in parallel with the increase in the concentration of application when low amounts were applied. In contrast, when high amounts were applied, the concentration of Cd in the aboveground parts of lettuce began to decrease. [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]

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]

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]

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]

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]

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 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]

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 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]

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]