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[Display omitted] • 5% biochar addition enhanced SMFC power and reduced ARG risks efficiently. • Excessive (10%) biochar addition would increase the abundance of ARGs. • Biochar impacted ARG spread via insertion sequences, transposases and prophages. • Biological factors showed a greater impact on ARGs than electrochemical effects. • Genetic material and amino acid synthesis controlled ARGs by influencing metabolism. This study is the first to explore the performance and mechanism of biochar-impacted sediment microbial fuel cell for removing antibiotic resistance genes (ARGs), and examines the effects of different biochar contents. The addition of 5% biochar produced the highest output voltage and power density, which increased by 100% and 219%, respectively, while simultaneously reducing the abundance and risk of ARGs. Comparatively, the addition of moderate amount of biochar (1–5%) promoted the removal of ARGs, while the opposite was true for excessive (10%) biochar. Biochar affected ARGs through prophages, insertion sequence, and transposons. Biological factors and voltage jointly influenced ARGs variation, with the former accounting for 56%. Further analysis of functional genes indicated that biochar controlled ARGs by regulating the synthesis of genetic material and amino acids to influence metabolism. Overall, findings of this study shed light on the potential removal of ARGs in microbial electrochemical systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar addition synchronously retained carbon and nitrogen during DGW composting. • The mechanism of biochar-enhanced carbon and nitrogen co-conservation is revealed. • Biochar inhibited CO 2 production and promoted carbon fixation to conserve carbon. • Nitrification and ammonia assimilation played vital roles in nitrogen retention. To elucidate the mechanism of biochar addition on carbon and nitrogen retention during distilled grain (DGW) composting, this study investigated the losses of carbon and nitrogen and functional genes related to carbon and nitrogen metabolisms between biochar-treated and control composts. The addition of biochar significantly increased carbon and nitrogen retention by 13.5% and 33.8%, respectively. The difference in core carbon metabolism genes indicated that biochar addition inhibited CO 2 release and promoted carbon fixation during the later composting phase, leading to improved carbon retention. Nitrogen metabolism analysis indicated that biochar addition suppressed early-phase ammoniation and late-phase denitrification and promoted nitrification and ammonia assimilation during the later stages of composting, thereby preserving nitrogen. During the later composting phase, biochar addition enhanced carbon–nitrogen coupling metabolism activity, leading to the synchronous retention of carbon and nitrogen. These findings elucidate the mechanism of biochar addition on carbon and nitrogen retention during DGW composting. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ensemble learning models, viz. RF, XGB, and AdaBoost were employed to predict biochar yield and HHV. • Random Forest model outperformed XGB and AdaBoost with an R2 = 0.86 for both yield and HHV prediction. • Pyrolysis temperature and ash content were the most influential features based on SHAP value analysis. • Partial dependence plots captured the nonlinear relationship among features and the target variable. Pyrolysis is an efficient thermochemical conversion process, but accurate prediction of yield and properties of biochar presents a significant challenge. Three prominent ensemble learning methods, viz. Random Forest (RF), eXtreme Gradient Boosting (XGB), and Adaptive Boosting (AdaBoost) were utilized to develop models to predict yield and higher heating value (HHV) of biochar. Dataset comprising 423 observations from 44 different biomasses was curated from peer-reviewed journals for predicting biochar yield. RF regressor achieved a test R2 of 0.86 for biochar yield, while XGB regressor achieved a test R2 of 0.87 for biochar HHV prediction. The SHapley Additive exPlanations (SHAP) analysis was conducted to assess influence of each feature on the model's output. Pyrolysis temperature and ash content of biomass were identified as the most influential features for the prediction of both yield and HHV of biochar. The partial dependence plots (PDPs) revealed nonlinear relationships, interpreting how the model formulates its predictions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microbial necromass carbon varied from 24.9 to 77.9 g/kg during composting. • Microbial necromass carbon constituted 5.77 %–21.3 % of total organic carbon. • Humic acid was closely related to microbial necromass carbon. • Abiotic factors and nutrient limitations affected microbial necromass production. • Biochar promoted the production and accumulation of microbial necromass carbon. Microbial necromass carbon (MNC) is an important stable organic C component. However, the variation of MNC and its potential relationship with humus components in composting remains uncertain. During a 45-day chicken manure composting study with and without biochar, MNC ranged from 24.9 to 77.9 g/kg and increased significantly by 80.9 % to 133 %. MNC constituted 5.77 % to 21.3 % of total organic C, with bacterial/fungal necromass C ratio ranging from 0.82 to 1.78. The MNC/humus C ratio ranged from 0.15 to 0.55, and humic acid C showed significant positive associations with bacterial necromass C (R2 = 0.72) and fungal necromass C (R2 = 0.51). Biochar addition reduced electrical conductivity and moisture content, increased pH, and induced microbial phosphorus limitation, thereby enhancing MNC content by 29.2 % and promoting humification. Our study is the first to elucidate the relationship between microbial necromass and humus substances, providing fundamental data for advancing the microbial carbon pump theory in composting. [ABSTRACT FROM AUTHOR]

[Display omitted] • For the first time pyrolysis was used for Heracleum sosnowskyi biomass utilization. • Potential applications of Heracleum sosnowskyi biochars as solid fuel and/or fertilizer was determined. • It is possible to convert Heracleum sosnowskyi into biochar without external energy. • Pyrolysis > 400 °C promotes the improvement of fertilizing properties Heracleum sosnowskyi biochar. • Using pyrolysis for Heracleum sosnowskyi utilization confirms its practical utility. The Heracleum sosnowskyi is a highly invasive plant species known for its rapid spread and the significant threat it poses to the ecosystem and human health, primarily due to its furanocoumarin content. In the present study, for the first time the pyrolysis process (200–600 °C) of Heracleum was conducted, demonstrating its efficacy in utilizing the material as feedstock and generating valuable solid by-products. It was found that biochar produced at temperatures of 200–300 °C is suitable for solid fuel production (HHV 20.2–24.1 MJ·kg−1) and has strong hydrophobic properties, while pyrolysis over 400 °C promotes the improvement of fertilizing properties by increasing the content of micro and macronutrients (K=112.4 g·kg−1 at 600 °C). The mass and energy analysis proved that in specific conditions (for dry > 300 °C; for wet > 400 °C), pyrolysis can be an effective way for Heracleum biomass conversion into valuable biochar without the need for external energy. [ABSTRACT FROM AUTHOR]

• A novel adsorbent (M−L−BC) using litchi seed via ZnCl 2 modification was synthesized. • M−L−BC showed excellent reusability and adsorption performance towards PFASs. • Adsorption kinetics followed the pseudo-second-order model (PSO). • M−L−BC effectively removed multi-PFASs from diverse water matrices. • The mechanisms were explored through characterizations and density functional theory. The present study successfully synthesized a novel biochar adsorbent (M−L−BC) using litchi seed modified with zinc chloride for PFASs removal in water. M−L−BC greatly enhanced removal of all examined PFASs (>95 %) as compared to the pristine biochar (<40 %). The maximum adsorption capacity was observed for PFOS, reaching 29.6 mg/g. Adsorption kinetics of PFASs followed the pseudo-second-order model (PSO), suggesting the predominance of chemical adsorption. Moreover, characterization and density functional theory (DFT) calculations jointly revealed involvement of surface complexation, electrostatic interactions, hydrogen bonding, and hydrophobic interactions in PFAS adsorption. Robust PFAS removal was demonstrated for M−L−BC across a wide range of pH (3–9), and coexisting ions had limited impact on adsorption of PFASs except PFBA. Furthermore, M−L−BC showed excellent performance in real water samples and retained reusability after five cycles of regeneration. Overall, M−L−BC represents a promising and high-quality adsorbent for efficient and sustainable removal of PFASs from water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Combining machine learning and physical insights to study biochar active sites. • Internal and external characters constructed multidimensional fingerprint descriptor. • C-C/C=C, C=O and defect sites were all predicted with over 90 % accuracy. • The descriptors enable high-throughput screening of preparation parameters. Highly active biochar has great application potential in heterogeneous catalysis and adsorptive processes. The complexity of carbonization process makes it difficult to construct target active sites. This work put forward a reactive descriptor based on pyrolysis parameters and intrinsic composition of biomass. Results show that the model showed better predictive performance for C-C/C=C (R2 = 0.85), C=O (R2 = 0.85) and defect (R2 = 0.91) sites. The SHapley Additive exPlanation analysis shows that the pyrolysis parameters and the higher heating values are equally important for the active sites. The predictive performance and guiding role of the descriptor were validated by experiments. The descriptors proposed in this study integrated significant advantages of simplicity and easy accessibility, which would break the bottleneck of accurate construction of active sites and provide a theoretical basis for high-value resource utilization of biomass. [ABSTRACT FROM AUTHOR]

[Display omitted] • Present in BC HM and PAHs are crucial considering biochar toxicity. • Predicting the bioavailability of PAHs using the total content is misleading. • Toxicity was influenced by BC's bioavailable PAHs > ash > total PAHs content. • Oxygen-containing functional groups were crucial in revealing the toxicity. • Indicating a safe material for soil and environmental applications is difficult. Agricultural or environmental application of biochar (BC) is connected with the introduction of biochar-derived components among which polycyclic aromatic hydrocarbons (PAHs) and heavy metals are the most toxic. Their presence and bioavailability are crucial considering biochar toxicity. The effect of feedstock and pyrolysis temperature on the physicochemical properties of produced biochar and contaminant content was established and combined with toxicity to a broad range of living organisms. The obtained data revealed that predicting the bioavailability of PAHs using the total content is misleading. The toxicity was influenced by factors in the following way: the bioavailable PAHs > ash > total PAHs content in BC stressing the role of BC physicochemical characteristics. Among tested BC properties, surface functionalization, e.g. presence of oxygen-containing functional groups was crucial in revealing the toxicity. The data clearly indicate that additional research is required to determine BC's impact on various organisms and performing one ecotoxicity test is not sufficient. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oil Palm Shell biomass conversion to Bio-Graphene via pyrolysis and CVD. • Partial and total covers growing settings were evaluated on Bio-Graphene growth. • Faster characterization through direct deposition of Bio-Graphene on a silicon wafer. • Better closed growing settings facilitate the growth of high-quality Bio-Graphene. Oil Palm Shell (OPS) is subjected to heating, resulting in gaseous compound release. These compounds are deposited on the substrate to produce Bio-Graphene. Through Chemical Vapor Deposition (CVD), the process is optimized by growing environment parameters during the production process. This process involves the controlled deposition of gaseous compounds onto a substrate under two different positions of the alumina boat (ABC-1 and ABC-2). Direct deposition on silicon wafers eliminated etching and transfer sequences, simplifying Bio-Graphene characterization. Field Emission Scanning Electron Microscope, Atomic Force Microscope, Raman Spectroscopy, X-ray diffraction, and I-V measurement were employed to characterize the Bio-Graphene. The findings revealed that the better-closed settings (ABC-2) facilitated the growth of high-quality Bio-Graphene with better crystallinity, detectable growth spurt, estimated few-layer thickness, larger growth area, and lower surface roughness. Optimizing the deposition environment at ABC-2 significantly enhances the quality and crystallinity of Bio-Graphene from OPS, paving the way for future applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Confinement of nano Mg-oxide in biochar was achieved via sequential doping of N and Mg. • More porous structure in biochar with smaller pore size was created by N pre-doping. • Nanosized MgO successfully induced the enhanced phosphate adsorption capacity. Advanced metal-doped biochar with superior phosphate (P) adsorption capacity plays a crucial role in combating eutrophication, depending on the rational design of the biochar structure for uniform and nanoscale dispersion of metal oxides. Herein, the nanoconfinement of magnesium oxide (MgO) was successfully attained in nitrogen pre-doped biochar (Mg/N-BC). The well-dispersed MgO was confined within nanoscale structure of Mg/N-BC, delivering P adsorption capacity of 108.41 mg g−1 and adsorption rate of 18.01 mg g-1h−1. More importantly, its adsorption performance at equilibrium 0.5 mg P/L was 17.70 times higher. Results suggested the decrease in pore size was positively correlated with the increase of N, confirming the role of N pre-doping in structure shaping and MgO confinement. The enhanced P adsorption was attributed to the well-dispersed MgO nanoparticles within the biochar. This study introduced a facile synthesis approach for biochar-incorporated nanoscale MgO, offering a new strategy for enhanced P removal. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chitin and chitosan hydrochars were prepared by hydrothermal and microwave treatments. • Adsorption capacities of hydrochars toward pharmaceuticals were compared. • The mechanism of pharmaceutical adsorption depended on the HT treatment temperature. • Alkaline activation of CS and CT biochars increases adsorption capacities by 5–40 %. Hydrothermal treatment of fishery waste-derived chitin (CT) and chitosan (CS) was performed to prepare hydrochar adsorbents for the removal of pharmaceuticals of environmental concern. By systematically studying the effect of treatment conditions on the biochar structure, the correlation between hydrochar properties and the adsorption capacities was clarified to optimize the adsorption performance. CS hydrochars obtained by lower-temperature treatment showed high adsorption capacities for the pharmaceuticals having carboxyl groups attributed to the electrostatic binding. A decrease in the density of available amines in CS hydrochars prepared at higher temperatures resulted in lower adsorption capacities and the manifestation of different adsorption mechanisms based on hydrophobic and π-π interactions. CT hydrochars showed lower adsorption capacities than CS hydrochars due to inefficient carbonization and lack of adsorption sites. The hydrochar adsorbents prepared in this study address simultaneously the problems of marine waste bioresource utilization and environmental cleaning from the emergent pollutants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pyrolysis is applied at different times to convert Oedogonium biomass into biochar. • Pyrolysis time affected on biochar properties and removal of heavy metals. • Biochar obtained from a 40 min pyrolysis time exhibits higher removal efficiency. • The Langmuir isotherm and PSO model are fitted to explain the adsorption mechanism. In this study, pyrolysis was performed at different times to convert Oedogonium biomass into biochar. The physicochemical properties show that the pyrolysis time significantly impacts structural and morphological changes in biochar samples. The influence of pyrolysis time on the removal of multiple heavy metals was investigated. Owing to the presence of abundant functional groups, inorganic minerals and porous nature, biochar obtained from a 40 min pyrolysis time showed higher removal efficiency of heavy metals compared to biochars pyrolyzed at 20 mins and 60 mins even with higher concentrations of metal ions. The maximum adsorption capacity was observed 9.33, 10.74, 322.58, 13.70 and 9.11 mg/g with the biochar prepared at the pyrolysis time of 40 mins for Co, Ni, Cu, Zn and Cd, respectively. The adsorption isotherm is well fitted with the Langmuir adsorption model for heavy metals adsorption, and the kinetic study is well-defined by a pseudo second-order model. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar promoted the in-situ enrichment of Lactiplantibacillus. • Biochar elevated acetic acid yields to 37 % during early fermentation. • The sucrose-biochar combination increased lactic acid content by 15 %. • The sucrose-biochar synergy reduced CH 4 by 24.15 % in vitro rumen tests. • Biochar is a favorable strategy for anaerobic fermentation of paper mulberry. This study investigated biochar effects, either alone or combined with sucrose, on fermentation quality, microbial communities, and in vitro rumen digestion of anaerobic fermented paper mulberry. The biochar alkaline functional groups bind to lactic acid, reducing acid inhibition and promoting Lactiplantibacillus proliferation. Owing to the low sugar content of paper mulberry, lactic acid bacteria in the biochar group primarily underwent heterofermentation, resulting in the lowest lactic and highest acetic acid contents. Treated with sucrose-loaded biochar, the increased substrate supported homofermentation, leading to the highest lactic and lowest acetic acid contents, with a 15.0 % increase in lactic acid and a 22.2 % decrease in ammoniacal nitrogen compared with the control after 75 days. In vitro rumen tests showed that the biochar-sucrose group had the highest dry matter degradation rate (45.9 %) and a 24.2 % reduction in methane emissions. Concludingly, sucrose-loaded biochar is recommended as effective for lactic acid production under anaerobic conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chitosan-coated magnetic biochar was prepared for amalgamation with C. pyrenoidosa. • Microalgae-biochar hybrid effectively removed SMX by adsorption and biodegradation. • Microalgae-biochar hybrid was easily recovered from wastewater. • The hybrid improved SMX removal (11.3%) and microalgae harvest efficiency (55.1%). • Two-stage coupling strategy increased SMX removal rate from 37.7% to 45.7%. The use of microalgae for antibiotic removal has received increasing attention due to its many advantages. However, challenges such as limited removal rates and the complexity of algae cell recovery persist. In this study, chitosan and FeCl 3 modified peanut shell biochar (CTS@FeBC) was prepared for the immobilization of Chlorella pyrenoidosa. The results showed that CTS@FeBC effectively adsorbed and immobilized microalgal cells to form microalgae-biochar hybrids, resulting in higher sulfamethoxazole removal rate (45.7 %) compared to microalgae (34.4 %) or biochar (20.0 %) alone, and higher microalgal lipid yield (11.6 mg/L d-1) than microalgae alone (10.1 mg/L d-1). More importantly, the microalgae-biochar hybrids could be rapidly separated from the wastewater within 10 min by applying a magnetic field, resulting in a harvesting efficiency of 86.3 %. Overall, the microalgae-biochar hybrids hold great potential in overcoming challenges associated with pollutants removal and microalgal biomass recovery. [ABSTRACT FROM AUTHOR]

[Display omitted] • Non-catalytic transesterification converted lipids in dairy sludge to biodiesel. • Calcium was recovered from defatted sludge-derived biochar. • Biochar residue after calcium recovery was used as an adsorbent for copper. Dairy sludge (DS) consists of organic compounds such as lipids and valuable inorganic elements. Biodiesel recovery from dairy sludge extract (DSE), using conventional acid (trans)esterification yielded only 16.5 wt%. In contrast, non-catalytic (trans)esterification generated a substantially higher biodiesel yield of approximately 74.0 wt% due to the method's tolerance for impurities. Defatted dairy sludge (DDS) contained a higher Ca concentration than DS. DDS-produced biochar (DDSB) increased its Ca concentration predominantly in the form of CaO. 91.1% of the Ca was recovered from the DDSB containing Ca. The Ca remaining in the biochar residue (DDSBR) after Ca recovery was in the form of CaCO 3. The porous structure developed as the Ca dissolved, implying that DDSBR could be an effective pollutant adsorbent. In this study, a method is proposed to maximize the utilization of DS by producing biodiesel, recovering Ca content, and using it as a pollutant adsorbent. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar with high suspension from agricultural wastes. • Biochar suspension parameters were fitted. • Pyridine nitrogen contributed to the suspension of biochar particles. • Particle size relation to media size affects media hydraulic conductivity. Biochar-based in-situ reaction zones are promising methods for groundwater remediation. However, the transport and retention of biochar in aquifer media remain unclear. Herein, biochar with high suspensibility was developed through nitrogen doping. A linear regression was used to analyze the relationship between particle size, concentration, time, and suspension rate. Seepage column experiments were conducted to investigate the transport and retention mechanisms of biochar in the aquifer medium. The ratio of biochar particle size (d p) to medium particle size (D p) affected the permeability coefficient. At a 3.0 g/L injected concentration, hydraulic conductivity decreased within 3.3 × 10−3 ≤ d p /D p ≤ 8.4 × 10−3. Within 9.7 × 10−3 ≤ d p /D p ≤ 1.9 × 10−2, hydraulic conductivity first increased and then decreased. Within 2.5 × 10−2 ≤ d p /D p ≤ 5.7 × 10−2, hydraulic conductivity slightly increased and then stabilized. This study confirms that nitrogen-doped biochar is an excellent remediation material for in-situ reaction zone. [ABSTRACT FROM AUTHOR]

• Microwave-heating with carbon fiber cloth gives efficient biochar yield performance. • Microwave-pyrolyzed char (MW) enhanced caproate production and selectivity. • MW enriched the dominance of Parabacteroides , Bacteroides , and Macellibacteroides. • MW significantly promoted both RBO and fatty acid biosynthesis pathways. The integration of biochar into microbial Chain Elongation (CE) proves to be an effective tool of producing high-value bio-based products. This study innovatively applied biochar fabricated under microwave irradiation with carbon fiber cloth assistance into CE system. Results highlighted that microwave biochar achieved maximal CE efficiency yielding 8 g COD/L, with 3-fold increase to the blank group devoid of any biochar. Microwave biochar also obtained the highest substrate utilization rate of 94 %, while conventional biochar group recorded 90 % and the blank group was of 74 %. Mechanistic insights revealed that the reductive surface properties facilitated CE performance, which is relevant to fostering dominant genera of Parabacteroides , Bacteroides , and Macellibacteroides. By metagenomics, microwave biochar up-regulated functional genes and enzymes involved in CE process including ethanol oxidation, the reverse β-oxidation pathway, and the fatty acid biosynthesis pathway. This study effectively facilitated caproate production by utilizing a new microwave biochar preparation strategy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Preparation of biochar and biofuels can be combined to reduce costs. • Cellulase treatment conditions affect biochar properties through distinct mechanisms. • Cellulase treatment can effectively improve the stability of biochar. • Improved stability includes low release/high thermal stability/anti-aging property. • This biochar overcomes the issue of structure disintegration in application. As the most abundant renewable carbon source, lignocellulose holds potential as a raw material for biofuels and biochar. The components required for biofuel production differ from those for biochar, so combining processes can reduce costs. Biofuel preparation necessitates cellulase treatment of lignocellulose. This study examines the effects of various enzyme treatment conditions (dosage, time, temperature) on lignocellulose, focusing on the properties of biochar derived from it (BC-SR). A mathematical model was constructed to study the relationship between enzyme treatment conditions and BC-SR properties. BC-SR exhibited high adsorption selectivity for bisphenol A and outperformed untreated biochar in fixed-bed column experiments, demonstrating greater removal efficiency and structural integrity. This study provides insights into the impact of enzymatic treatment on biochar and offers a cost-effective method for producing stable, efficient biochar. Additionally, a highly persistent biochar can enter the carbon trading market as a carbon–neutral technology, further realizing economic and environmental benefits. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar-amended sequencing batch reactors exhibited improved nitrification. • Biofilms on biochar surfaces were enriched for ammonia oxidizing bacteria. • SNARF-4F fluorescent microscopy characterized pH microenvironments of biochar. • Biofilms stabilize pH at biochar surfaces and sustain adsorption of ammonia. The effects of biochar on aerobic nitrification in activated sludge were investigated in sequencing batch reactors. Biochar amended reactors exhibited 87–94 % lower ammonia in effluent and 16–71 % greater removal of total Kjeldahl nitrogen compared to control reactors. Quantitative qPCR analyses revealed that the relative abundance of ammonia oxidizing bacteria (AOB, amoA/ 16S rRNA genes) was greater in biochar than in control reactors. AOB were enriched on biochar surfaces, with biochar particles having up to 12.1 times greater relative abundance of AOB compared to suspended biomass. Biochar's maximum ammonia sorption capacity of 4.4 mg N/g at pH 7 decreased with decreasing pH, however a pH-sensitive fluorescent probe was used to show that biofilms growing on biochar surfaces maintain a median pH of > 6.7 despite reactor acidification by nitrification. Microbial colonization of biochar in activated sludge creates a pH-sheltered environment that sustains biochar's ammonia sorption capacity, resulting in enrichment of AOB on biochar particles and improved nitrification. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ball-milling nano-MgO loaded biochar forms glucose isomerization catalyst. • Ball milling pretreatment facilitates the dispersion of MgO in biochar. • The catalyst affords 32.5 % fructose yields from glucose in 100 min reaction time. • Low activation energy of 89.76 kJ mol−1 achieved for reaction with MgO/biochar. • MgO/biochar can be recycled for at least five cycles without loss of activity. The isomerization of glucose is a crucial step for biomass valorization to downstream chemicals. Herein, highly dispersed MgO doped biochar (BM-0.5@450) was prepared from rice straw via a solvent-free ball milling pretreatment and pyrolysis under nitrogen conditions. The nano-MgO doped biochar demonstrated enhanced conversion of glucose in water at low temperatures. A 31 % yield of fructose was obtained from glucose over BM-0.5@450 at 50 °C with 80.0 % selectivity. At 60 °C for 140 min, BM-0.5@450 achieved a 32.5 % yield of fructose. Compared to catalyst synthesized from conventional impregnation method (IM@450), the BM-0.5@450 catalyst shows much higher fructose yields (32.5 % vs 25.9 %), which can be attributed to smaller crystallite size of MgO (11.32 nm vs 19.58 nm) and homogenous distribution. The mechanism study shows that the activated MgOH+·OH− group by water facilitated the deprotonation process leading to the formation of key intermediate enediol. [ABSTRACT FROM AUTHOR]

[Display omitted] • N doping promoted the conversion of guaiacol and enhanced the formation of cyclohexanol. • Acidity modulation of Co-supported N-doped carbon catalyst enhanced C–O bond cleavage. • Catalyst formation mechanism was identified by DFT calculations. • N dopants collaborating alumina can improve the activity and stability of hybrid catalysts. Bio-oil derived from biomass fast pyrolysis can be upgraded to gasoline and diesel alternatives by catalytic hydrodeoxygenation (HDO). Here, the novel nitrogen-doped carbon–alumina hybrid supported cobalt (Co/NCA n , n = 1, 2.5, 5) catalyst is established by a coagulation bath technique. The optimized Co/NCA 2.5 catalyst presented 100 % conversion of guaiacol, high selectivity to cyclohexane (93.6 %), and extremely high deoxygenation degree (97.3 %), respectively. Therein, the formation of cyclohexanol was facilitated by stronger binding energy and greater charge transfer between Co and NC which was unraveled by density functional theory calculations. In addition, the appropriate amount of Lewis acid sites enhanced the cleavage of the C–O bond in cyclohexanol, finally resulting in a remarkable selectivity for cyclohexane. Finally, the Co/NCA 2.5 catalyst also exhibited excellent selectivity (93.1 %) for high heating value hydrocarbon fuel in crude bio-oil HDO. This work provides a theoretical basis on N dopants collaborating alumina hybrid catalysts for efficient HDO reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co-composting improves the quality of the final product. • Addition of beef bone biochar reduced the available nutrients in vermicompost. • Membrane covered composting promotes lignin degradation in subsequent stages. • The best treatments have excellent properties that facilitate their application. • Membrane-covered compost synergized with biochar promotes earthworm growth. The sustainable management of agricultural waste is essential for curtailing environmental contamination. To address the shortcomings of single treatment methods, this study evaluated the feasibility of combining membrane-covered composting (MC) with vermicomposting. Based on this, the integrated effects of different biochar addition strategies on the combined process were investigated. The aim was to improve the efficiency of vermicomposting while eliminating the negative effects of biochar on earthworms. Addition of biochar before membrane-covered composting increased total earthworm biomass by 25.6 − 31.4 % and reproduction rate by 13.4 − 23.9 %. Specifically, the electrical conductivity (EC) (1061.0 − 1112.0 uS/cm) of the vermicompost was significantly reduced, while the total nutrient content (42.3 − 42.6 mg/g) and germination index (GI) (103.9 − 108.4 %) were maximized. Additionally, reductions in the carbon-to-nitrogen ratio and volatile content were observed. Overall, combination process is a promising approach to improve the quality of vermicomposting. The study's results offer a novel perspective on the value-added treatment of agricultural waste. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar can significantly enhance NO 3 — reduction rather than NO 2 — reduction. • Biochar stimulates DAMO archaea to secrete EPS as an electron carrier. • The electrons produced from reverse methanogenesis are transferred to membrane for NO 3 — reduction. • The intracellular electron transfer of DAMO archaea is enhanced by biochar. Denitrifying anaerobic methane oxidizing (DAMO) archaea plays a significant role in simultaneously nitrogen removal and methane mitigation, yet its limited metabolic activity hinders engineering applications. This study employed biochar to explore its potential for enhancing the metabolic activity and nitrate reduction capacity of DAMO microorganisms. Sawdust biochar (7 g/L) was found to increase the nitrate reduction rate by 2.85 times, although it did not affect the nitrite reduction rate individually. Scanning electron microscopy (SEM) and fluorescence excitation-emission matrix (EEM) analyses revealed that biochar promoted microbial aggregation, and stimulated the secretion of extracellular polymeric substances (EPS). Moreover, biochar bolstered the redox capacity and conductivity of the biofilm, notably enhancing the activity of the electron transfer system by 1.65 times. Key genes involved in intracellular electron transport (Hdr, MHC, Rnf) and membrane transport proteins (BBP, ABC, NDH) of archaea were significantly up-regulated. These findings suggest that biochar regulates electrons generated by reverse methanogenesis to the membrane for nitrate reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar simultaneously promoted methane production and phosphorus transformation. • 300 °C and 0.075 g∙g−1 of biochar were the optimal temperature and dosage. • BC300 promoted an 18% increase in the proportion of active phosphorus. • Biochar may facilitate the hydrogenotrophic methanogenic pathway. • Synergistic effect of microorganisms increased the proportion of active phosphorus. Biochar has been proved to improve methane production in high solids anaerobic co-digestion (HS-AcoD) of dewatered sludge (DS) and food waste (FW), but its potential mechanism for simultaneous methane production and phosphorus (P) transformation has not been sufficiently revealed. Results showed that the optimal preparation temperature and dosage of sludge-based biochar were selected as 300 °C and 0.075 g·g−1, respectively. Under this optimized condition, the methane production of the semi-continuous reactor increased by 54%, and the active phosphorus increased by 18%. The functional microorganisms, such as Methanosarcina , hydrogen-producing, sulfate-reducing, and iron-reducing bacteria, were increased. Metabolic pathways associated with sulfate reduction and methanogenesis, especially hydrogenotrophic methanogenesis, were enhanced, which in turn promoted methanogenesis and phosphorus transformation and release. This study provides theoretical support for simultaneously recovery of carbon and phosphorus resources from DS and FW using biochar. [ABSTRACT FROM AUTHOR]

[Display omitted] • Low-release biochar (BC-LR) can promote microbial autotrophic metabolism. • BC-LR can adsorb microbial metabolites to reduce its feedback inhibition effect. • BC-LR can selectively adsorb the main inhibitory components in metabolites. • Without low release characteristics, biochar may inhibit microbial CO 2 fixation. • BC-LR has the advantages of high cost-effective and biocompatibility in application. Chemoautotrophs, the crucial contributors to biological carbon fixation, derive energy from reducing specific inorganic substances and utilize CO 2 for growth. However, the release of extracellular free organic carbon (EFOC) by chemoautotrophic microorganisms can inhibit their own growth and metabolism. To reduce the feedback inhibition effect, a low-release biochar (BC-LR) was applied to adsorb EFOC. BC-LR not only adsorbed EFOC, but also selectively adsorbed the main inhibitory component, low molecular weight organics, in EFOC. In contrast, ordinary biochar could not effectively adsorb EFOC and its addition inhibited microbial growth and CO 2 fixation. In Transwell culture, BC-LR promoted microbial growth by 190% and CO 2 fixation by 29%, and exhibited better economic advantage, when compared with granular activated carbon. These findings provide a novel insight into the interaction between biochar and autotrophic microbial metabolism, offering an economically feasible approach to mitigate feedback inhibition of metabolites and promoting biological CO 2 fixation. [ABSTRACT FROM AUTHOR]

[Display omitted] • 3D core–shell structure biochar catalyst derived from walnut-shell was synthesized. • BC@CoNi-600/PMS system achieved 100% degradation of SMX and repeated stability. • Molecular probes quantified the ROS transformation in the BC@CoNi-600/PMS system. • Machine learning method proposed the multiscale effect of SMX degradation. In this study, a 3D CoNiO 2 /Co core–shell structure biochar catalyst derived from walnut shell was synthesized by hydrothermal and ion etching methods. The prepared BC@CoNi-600 catalyst exhibited exceptional peroxymonosulfate (PMS) activation. The system achieved 100 % degradation of sulfamethoxazole (SMX). The reactive oxygen species in the BC@CoNi-600/PMS system included SO 4 −, OH, and O 2 −. Density functional theory calculations explored the synergistic effects between nickel–cobalt bimetallic and carbon matrix during PMS activation. The unique 3D core–shell structure of BC@CoNi-600 features an outer nickel–cobalt bimetallic layer with exceptional PMS adsorption capacity, while protecting the zero-valence Co of the inner layer from oxidation. Based on the experimental-data, machine learning modeling mechanism, and information theory, a nonlinear modeling method was proposed. This study utilizes a machine learning approach to investigate the degradation of SMX in complex aquatic environments. This study synthesized a novel biochar-based catalyst for activated PMS and provided unique insights into its environmental applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar added at the beginning of composting reduced 55% of total N 2 O emission. • N 2 O emission showed significant relationships with most environmental factors. • Biochar mitigated N 2 O mainly by regulating the physicochemical properties of compost. • Genes and enzymes influenced the overall effect of environmental factors to N 2 O. The effects and mitigation mechanisms of biochar added at different composting stages on N 2 O emission were investigated. Four treatments were set as follows: CK: control, B B10% : +10 % biochar at beginning of composting, B B5%&T5% : +5% biochar at beginning and + 5 % biochar after thermophilic stage of composting, B T10% : +10 % after thermophilic stage of composting. Results showed that treatment B B10% , B B5%&T5% , and B T10% reduced total N 2 O emissions by 55 %, 37 %, and 36 %, respectively. N 2 O emission was closely related to most physicochemical properties, while it was only related to amoA gene and hydroxylamine oxidoreductase. Different addition strategies of biochar changed the contributions of physicochemical properties, functional genes and enzymes to N 2 O emission. Organic matter and C/N contributed 23.7 % and 27.6 % of variations in functional gene abundances (P < 0.05), respectively. pH and C/N (P < 0.05) contributed 37.3 % and 17.3 % of variations in functional enzyme activities. These findings provided valuable insights into mitigating N 2 O emissions during composting. [ABSTRACT FROM AUTHOR]

[Display omitted] • First study on caproate biosynthesis from soybean dreg. • Optimized parameters for the conversion of soybean dreg to caproate. • Ethanol and lactate yielded from soybean dreg as co-ED enhancing caproate production. • Biochar shortens the lag phase and upregulates pivotal genes' relative abundance. • Lysinibacillus and Pseudomonas cooperation may play a crucial role in CE process. To address the environmental hazards posed by high-yield soybean dreg (SD), a high-value strategy is firstly proposed by synthesizing caproate through chain elongation (CE). Optimized conditions for lactate-rich broth as intermediate, utilizing 50 % inoculum ratio, 40 g/L substrate concentration, and pH 5, resulting in 2.05 g/L caproate from direct fermentation. Leveraging lactate-rich broth supplemented with ethanol, caproate was optimized to 2.76 g/L under a refined electron donor to acceptor of 2:1. Furthermore, incorporating 20 g/L biochar elevated caproate production to 3.05 g/L and significantly shortened the lag phase. Mechanistic insights revealed that biochar's surface-existed quinone and hydroquinone groups exhibit potent redox characteristics, thereby facilitating electron transfer. Moreover, biochar up-regulated the abundance of key genes involved in CE process (especially fatty acids biosynthesis pathway), also enriching Lysinibacillus and Pseudomonas as an unrecognized cooperation to CE. This study paves a way for sustainable development of SD by upgrading to caproate. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar and Moringa show potential for treating greywater, but with limitations. • Greywater quality reflects local conditions. • Batch stirring and filtration can improve colour, turbidity and nutrient levels. • Challenges include increased levels of total organic carbon and dissolved solids. • Reusing treated greywater can improve water access for vulnerable communities. This study investigated the potential of using biochar and Moringa oleifera seed proteins for sustainable greywater treatment in rural Kenya. Greywater samples from washing clothes were collected from households in the Kenyan counties of Kwale and Siaya. Two treatment methods, batch stirring and filtration, were used to assess the effectiveness of using biochar and Moringa oleifera seed protein extract together to treat greywater at a household level. Both methods achieved a significant reduction in contaminants: colour was reduced by up to 43% in Kwale and 67% in Siaya, turbidity decreased by 91–98%, and surfactant levels were lowered by 89–93%. There were increases in total organic carbon and total dissolved solids post-treatment, but both methods effectively reduced levels of phosphates, nitrates and iron. This research highlights the potential of using locally available materials for greywater treatment and provides insights into sustainable water management nature-based solutions in the Global South. [ABSTRACT FROM AUTHOR]

[Display omitted] • Endogenous MgSiO 3 -based biochar presented ultra-stability after adsorption. • Soluble silicate and active OH endowed biochar with stable and rapid Cd adsorption. • β-CD@SiBC can meet the upper limit of Cd (0.05 mg L−1) under high Cd conditions. • Mineral (36 %) and ion exchange (29 %) in β-CD@SiBC dominated Cd removal from water. This work proposes an advanced biochar material (β-CD@SiBC) for controllable transformation of specific silicon (Si) forms through endogenous Si activation and functional group introduction for efficient cadmium (Cd) immobilization and removal. The maximum adsorption capacity of β-CD@SiBC for Cd(II) reached 137.6 mg g−1 with a remarkable removal efficiency of 99 % for 200 mg L−1Cd(II). Moreover, the developed β-CD@SiBC flow column exhibited excellent performance at the environmental Cd concentration, with the final concentration meeting the environmental standard for surface water quality (0.05 mg L−1). The remediation mechanism of β-CD@SiBC could be mainly attributed to mineral precipitation and ion exchange, which accounted for 42 % and 29 % of the remediation effect, respectively, while functional group introduction enhanced its binding stability with Cd. Overall, this work proposes the role and principle of transformation of Si forms within biochar, providing new strategies for better utilizing endogenous components in biomass. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1.05% FeSO 4 and 5.25% biochar co-additives optimally improved EAC. • Fmax of C1 and C2 were higher by 47.47% and 26.69% than control with optimal additive. • The additive enhanced HA precursor functional groups accumulation of DOM in EAC. • Humified functional bacteria were enriched to promote HA formation with additives. • The additive intensified the MEN robustness and connection among microorganisms. This study assessed the impact of nine mixed ferrous sulfates and biochars on electric field-assisted aerobic composting (EAC), focusing on the spectroscopy of dissolved organic matter (DOM) and microbial communities. Adding 1.05% ferrous sulfate and 5.25% biochar to EAC increased the specific ultraviolet absorbances at 254 and 280 nm by 142.3% and 133.9% on day 35, respectively. This ratio accelerated the early response of carboxyl groups (—COOH) and lignin (CꘌC), enhancing the relative abundance of Thermobifida (4.0%) and Thermopolyspora (4.3%). The condition contributed to humus precursor formation on day 5, increasing the maximum fluorescence intensity of the humus-like component by 74.2% compared to the control on day 35. This study is the first to develop a combined and efficient organic and inorganic additive by multiple-variable experimentation for DOM humification. Consequently, it optimizes EAC for solid waste recycling. [ABSTRACT FROM AUTHOR]

• A Convolutional Neural Network model was developed for capacitance prediction. • Weight Analysis Feature Importance was firstly employed for model interpretation. • The most important feature affecting capacitance was specific surface area. • The model exhibited strong generalization ability by experimental validation. N-doped porous biochar is a promising carbon material for supercapacitor electrodes due to its developed pore structure and high chemical activity which greatly affect the capacitive performance. Predicting the capacitance and exploring the most influential factors are of great significance because it can not only avoid the trial-and-error experiments but also provide guidance for the synthesis of biochar with the aim of capacitance enhancement. In this study, a CNN model with ReLU activation function was established using DenseNet architecture for specific capacitance prediction. The importance and impacts of the physiochemical properties of N-doped porous biochar to the capacitance were revealed. With the guidance of the model, N-doped porous biochar samples with high capacitance were synthesized, the data of which were further used for model validation. This study provides not only a deep learning model which can be used in practice for capacitance prediction but also directions for the synthesis of N-doped porous biochar with high capacitive performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • GBR are the best model to predict metal-modified biochar's adsorption performance. • LoadC, WV, and pH are the key features that affect adsorption performance. • Experimental validation results are in good agreement with model prediction. • Mg or La-based biochar is suitable for high or low-concentration phosphate wastewater. Developing an optimized and targeted design approach for metal-modified biochar based on water quality conditions and management is achievable through machine learning. This study leveraged machine learning to analyze experimental data on phosphate adsorption by metal-modified biochar from literature published in Web of Science. Using six machine learning models, the phosphate adsorption capacity of biochar and residual phosphate concentration were predicted. After hyperparameter optimization, the gradient boosting model exhibited superior training performance (R2 > 0.96). Metal load quantity, solid–liquid ratio, and pH were key factors influencing adsorption performance. Optimal preparation parameters indicated that Mg-modified biochar achieved the highest adsorption capacity (387–396 mg/g), while La-modified biochar displayed the lowest residual phosphate concentration (0 mg/L). The results of verification experiments based on optimized process parameters closely aligned with model predictions. This study introduces a new machine learning–based approach for tailoring biochar preparation processes considering different water quality management objectives. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chinese herb residue was used as a low-cost feedstock for CMBC production. • CMBC showed superior adsorption performance for Cr(VI), As(III), and Pb(II) removal. • Multi-heavy metals were effectively separated from a variety of water bodies by CMBC. • DFT revealed that –COOH contributes more to heavy metals removal than –OH and –NH 2. In this study, the sorption properties of Cr(VI), As(III), and Pb(II) on chitosan-modified magnetic biochar (CMBC) derived from residues of Ligusticum chuanxiong Hort. were investigated. CMBC was found to be a valuable material for removing three heavy metals from water simultaneously. Kinetic analysis suggested Cr(VI), As(III), and Pb(II) were chemisorbed onto CMBC, while isotherm data conformed well to Langmuir model, the maximum adsorption capacity of CMBC was found to be 65.74 mg/g for Cr(VI), 49.32 mg/g for As(III), and 69.45 mg/g for Pb(II). Experiments, characterization, and density functional theory (DFT) calculations were employed to explore the mechanisms. Furthermore, CMBC demonstrated excellent removal rates of over 95% for Cr(VI), 99% for As(III) and Pb(II) from contaminated water bodies. This work shows that CMBC holds significant potential for wastewater treatment of heavy metals and provides an effective solution for the utilization of Chinese herb residues in environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Urban food waste—green infrastructure nexus is feasible. • Food waste digestate significantly promoted green roof plant growth and functions. • Food waste digestate is better than digestate biochar in green roof promotion. • 20% performed better than 10% both in digestate and digestate biochar. Waste—Green Infrastructure Nexus is crucial to mitigate carbon emissions in waste disposal and promote eco-functions of green infrastructure in a circular bio-economy. Our purpose is to verify the feasibility of the nexus via "food waste anaerobic digestion — digestate/digestate biochar — green roof promotion". The results found that food waste digestate and digestate biochar significantly promoted green roof plant growth, evapotranspiration, rainwater retention, runoff reduction, and prevention of nutrient leaching. Digestate treatments were better than digestate biochar for the green roof promotion. The promotion ranked consistently with 20 % digestate > 10 % digestate > 20 % digestate biochar > 10 % digestate biochar > control in stolon growth, leaf emergence, branching of Paspalum vaginatum , green roof establishment, rainwater retention, runoff reduction, and the leaching of nitrogen, phosphorus, potassium. This study demonstrated that food waste could be regenerated to promote urban green infrastructure to form a circular bio-economy by the Waste—Green Infrastructure Nexus. [ABSTRACT FROM AUTHOR]

[Display omitted] • Advanced anaerobic digestion sludge-based biochar was characterized. • Addition of biochar could enhance the dewatering performance of sludge. • Best dosage of biochar was 20% (dry solid) for sludge conditioning. The utilization of sludge-based biochar, characterized by abundant pore structures, proves advantageous in enhancing sludge dewatering performance. In this study, advanced anaerobic digestion sludge underwent pyrolysis to produce biochar, subsequently employed for sludge conditioning. Results revealed that biochar, obtained at 800 °C, exhibited the highest specific surface area (105.3 m2/g) and pore volume (0.17 cm3/g). As the pyrolysis temperature increased, the sludge's functional groups tended to aromatize. When used to condition sludge, particularly at a 20 % (dry solid) dosage, biochar significantly reduced sludge capillary suction time and floc size. The addition of biochar enhanced the conditioning effect of cationic polyacrylamide by absorbing extracellular polymeric substances, creating water molecule channels, and forming skeletons for sludge flocs. These findings introduce a novel approach to sludge reuse and provide valuable data supporting the use of biochar as a sludge conditioner. [ABSTRACT FROM AUTHOR]

[Display omitted] • Additives reduced NH 3 emission and the N 2 O emission by 29.3–42.9% and 53.3–65.8%. • The abundance of core bacteria related to N retention were increased by additives. • Core function genes abundance for NH 3 and N 2 O emission were reduced by additives. This study investigated the effects of crayfish shell powder (CSP) and bamboo-derived biochar (BDB) on nitrogen metabolism, bacterial community and nitrogen functional genes during pig manure composting. Four treatments were established: CP (with no additives), TP1 (5 % BDB), TP2 (5 % CSP) and TP3 (2.5 % BDB + 2.5 % CSP). Compared to CP, the germination index (GI) of TP reached > 85 % 10 days earlier. Meanwhile, TP3 reduced NH 3 and N 2 O emissions by 42.90 % and 65.9 %, respectively, while increased TN (total nitrogen) concentration by 5.43 g/kg. Furthermore, additives changed the bacterial structure and formed a beneficial symbiotic relationship with essential N-preserving bacteria, thereby enhancing nitrogen retention throughout the composting process. Metagenomic analysis revealed that additives upregulated nitrification genes and downregulated denitrification and nitrate reduction genes, ultimately improving nitrogen cycling and mitigating NH 3 and N 2 O emissions. In conclusion, the results confirmed that TP3 was the most effective treatment in reducing nitrogen loss. [ABSTRACT FROM AUTHOR]

[Display omitted] • Emerging contaminants (ECs) removal by biochar was modeled by machine learning (ML) • ML and classical adsorption models were coupled to build models. • Ash content of biochar had most critical influences on the adsorption speed of ECs. • Surface structure of biochar played a dominant role in maximum adsorption capacity. • An interactive Biochar-ECs platform was designed for users based on our ML models. Insights into key properties of biochar with a fast adsorption rate and high adsorption capacity are urgent to design biochar as an adsorbent in pollution emergency treatment. Machine learning (ML) incorporating classical theoretical adsorption models was applied to build prediction models for adsorption kinetics rate (i.e., K) and maximum adsorption capacity (i.e., Q m) of emerging contaminants (ECs) on biochar. Results demonstrated that the prediction performance of adaptive boosting algorithm significantly improved after data preprocessing (i.e., log-transformation) in the small unbalanced datasets with R 2 of 0.865 and 0.874 for K and Q m , respectively. The surface chemistry, primarily led by ash content of biochar significantly influenced the K, while surface porous structure of biochar showed a dominant role in predicting Q m. An interactive platform was deployed for relevant scientists to predict K and Q m of new biochar for ECs. The research provided practical references for future engineered biochar design for ECs removal. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar enhanced nitrogen removal at 15 ± 1 °C. • Biochar accelerated the establishment of anammox at 15 ± 1 °C. • Biochar stimulates anammox bacteria to secrete EPS at 15 ± 1 °C. • Candidatus Brocadia was enriched at 15 ± 1 °C. This study explored the use of biochar to accelerate the establishment of anaerobic ammonium oxidation (anammox) reactors operating at 15 ± 1℃. Incorporating 10 g/L bamboo charcoal in S1 accelerated the start-up of anammox in 87 days, which was significantly shorter than 103 days in S0 (without biochar). After 140 days, S1 exhibited a 10.9 % increase in nitrogen removal efficiency due to a 28.9 % elevation in extracellular polymeric substances, bolstering anammox bacterial resilience. Predominant anammox bacteria (Cadidatus Brocadia and Cadidatus Jettenia) showed relative abundances of 3.19 % and 0.38 % in S1, respectively, which were significantly higher than 0.40 % and 0.05 % in S0. Biochar provides favorable habitats for the enrichment of anammox bacteria and accelerates the establishment of anammox at low temperatures. This finding holds promise for enhancing the efficiency of anammox in cold climates and advancing sustainable wastewater nitrogen removal. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new type of co-pyrolysis biochar capable of adsorbing Cd (II) was prepared. • To tackle disposal of ADSR, treatment of OBDCA, and removal of Cd (II) concurrently. • The adsorption effect of biochar on Cd (II) is mainly mineral precipitation. • Adding OBDCA at over 500 °C enhances co-pyrolysis biochar's Cd (II) adsorption. Ionic cadmium (Cd (II)) in water is a significant threat to ecosystems, the environment, and human health. Research is currently focused on developing efficient adsorption materials to combat Cd (II) pollution in water. One promising solution involves co-pyrolyzing solid residue from anaerobic digestion of food waste with oil-based drill cuttings pyrolysis residue to create a biochar with high organic matter content. This biochar has a lower heavy metal content and leaching toxicity compared to China's national standards, making it both safe and resourceful. It exhibits a high adsorption capacity for Cd (II) in water, reaching up to 47.80 ± 0.37 mg/g. Raising the pyrolysis temperature above 600 °C and increasing the amount of pyrolysis residue beyond 30 % enhances the biochar's adsorption capacity. The adsorption process is primarily driven by mineral precipitation, offering a promising approach for dual waste resource management and reducing heavy metal pollution. [ABSTRACT FROM AUTHOR]

[Display omitted] • Modification by Fe and Si produces novel Fe-containing silicate in biochar. • Fe introduced in biochar promotes Si dissolution to enhance precipitation of CdSiO 3. • Synergistic effect of Fe and Si in biochar on Cd adsorption was identified. • The Cd removal effect using Fe/Si modified biochar is controlled by chemical reaction. The interaction mechanisms of silicon (Si) and active ingredient iron (Fe) on cadmium (Cd) removal are still unknown. Herein, the Fe/Si modified biochar (Fe/Si-BC) was synthesized to enhance Cd removal by pre-immersion of Fe and ball milling loading of Si. Detailed characterizations indicated that Fe and Si were successfully introduced into Fe/Si-BC, resulting in the formation of a new metallic silicate (Ca 2.87 Fe 0.13 (SiO 3) 2). The maximum Cd adsorption capacity of Fe/Si-BC (31.66 mg g−1) was 3.6 times and 2.5 times higher than that of Fe-BC (8.89 mg g−1) and Si-BC (11.03 mg g−1), respectively, deriving from an enhancement of Si dissolution induced by Fe introduction. The dissolved Si could capture and combine Cd to form CdSiO 3 precipitation, which was strongly supported by the random forest regression and correlation between dissolved Si content and Cd adsorption capacity. This study advances the mechanistic insights into synergistic functions of Si and Fe in Cd removal. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar enhances CO 2 capture, increasing the solubility by up to 25.8 mmol/L. • CO 2 concentrated with biochar improves cumulative methane yield by 24 % maximally. • Exogenous CO 2 reduces ΔG overall by approximately double. • Exogenous CO 2 can enhance RET, in which the CO 2 can be converted into formate. • Biochar-concentrated CO 2 enrichs syntrophic bacteria and their partner M. hungatei. Acid accumulation and carbon emission are two major challenges in anaerobic digestion. Syntrophic consortia can employ reverse electron transfer (RET) to facilitate thermodynamically unfavorable redox reactions during acetogenesis. However, the potential mechanisms and regulatory methods of RET remain unclear. This study examines the regulatory mechanisms by which exogenous CO 2 affects RET and demonstrates that biochar maximizes CO 2 solubility at 25.8 mmol/L to enhance effects further. CO 2 synergized with biochar significantly increases cumulative methane production and propionate degradation rate. From the bioenergetic perspective, CO 2 decreases energy level to a maximum of −87 kJ/mol, strengthening the thermodynamic viability. The underlying mechanism can be attributed to RET promotion, as indicated by increased formate dehydrogenase and enrichment of H 2 /formate-producing bacteria with their partner Methanospirillum hungatei. Moreover, the 5 % 13CH 4 and methane contribution result show that CO 2 accomplishes directed methanogenesis. Overall, this investigation riches the roles of CO 2 and biochar in AD surrounding RET. [ABSTRACT FROM AUTHOR]

• Lignin chemical structure affect the adsorption properties of lignin carbon. • Increased aromatic carbon improves the adsorption of methylene blue by lignin-derived carbon. • Pore adsorption can significantly affect the adsorption properties of lignin-derived carbon. • The maximum adsorption capacity of lignin-derived carbon for methylene blue was 526.32 mg/g. • After 6 cycles, lignin-derived carbon still removed 95.04% of methylene blue. The growing interest in utilizing lignin for dye removal has gained momentum, but there is limited information on the intricate relationship between lignin structural characteristics and adsorption efficacy, especially for its biochar derivatives. This study focused on three types of lignin and their corresponding biochar derivatives. Among them, ZnCl 2 -activated acidic/alkali densified lignin preparation of lignin-derived active carbon exhibited superior adsorption performance, achieving 526.32 mg/g for methylene blue and 2156.77 mg/g for congo red. Its exceptional adsorption capacity was attributed to its unique structural properties, including low alkyl and O-alkyl group content and high aromatic carbon levels. Furthermore, the adsorption mechanisms adhered to pseudo-second-order kinetics and the Langmuir model, signifying a spontaneous process. Intriguingly, lignin-derived active carbon also demonstrated remarkable recovery capabilities. These findings provide valuable insights into the impact of structural attributes on lignin and its biochar's adsorption performance. [ABSTRACT FROM AUTHOR]

• Elemental sulfur reduces biochar pH, making it a suitable amendment for arid lands. • Elemental sulfur increases soluble cations, reducing biochar basicity and buffering. • Sulfur alters biochar microbial communities, enhancing nutrient availability. • Compost addition to biochar increases microbial diversity, aiding sulfur oxidation. • Compost increases biochar nutrient availability and sulfur-oxidizing bacteria. This study aimed to improve biochar's quality for arid land applications by using elemental sulfur as a pH reducer agent co-applied with compost or vermicompost as biological activators. Biochar pH was decreased by the addition of elemental sulfur, with the highest reduction from 8.1 to 7.2 occurring when co-amended with vermicompost. Elemental sulfur increased the water-soluble concentrations of calcium, magnesium, and many other elements, and stimulated substrate-induced respiration, especially when co-amended with vermicompost. The bacterial diversity community structure were significantly affected by all treatments. The Shannon index significantly increased in response to compost and sulfur treatments, while the vermicompost treatments showed higher microbial evenness and equitability diversity indices. Multivariate analyses indicated that elemental sulfur oxidation was associated with specific sulfur-oxidizing bacterial clusters. Integrating biochar with sulfur and (vermi)compost was found to be a promising sustainable technology for managing excessive biochar alkalinity, increasing its fertility and potential for application in aridlands. [ABSTRACT FROM AUTHOR]

The activation of hemp stalk-derived homologous biochar-based catalysts with persulfate demonstrates distinct mechanisms, whereby porous biochar favors radical pathways and N-doped biochar utilizes non-radical electron transfer pathways, thereby highlighting their potential in the control of environmental pollution. [Display omitted] • Biochar (BC) and N-doped in biochar (NBC) are used to activate persulfate (PS). • N-doping leads to a different activation mechanism compared to BC. • BC-PS system operates a radical pathway with a removal rate of 89%. • NBC-PS system operates a non-radical pathway with a removal rate of 96%. Advancements in biochar activating persulfate advanced oxidation processes (PS-AOP), have gained significant attention. However, the understanding of biochar-based catalysts in activating PS remains limited. Herein, biochar (BC) and N-doped biochar (NBC) were synthesized from hemp for activating PS to treat tetracycline (TC) wastewater and analyzed their mechanisms separately. Surprisingly, N-doped in biochar leads to a change in the activation mechanism of PS. The BC-PS system operates mainly through a radical pathway, advantageous for treating soil organic pollution (68%) with pH adaptability (less than 10% variation). Nevertheless, the NBC-PS system primarily employs an electron transfer non-radical pathway, demonstrating stability (only 7% performance degradation over four cycles) and enhanced resistance to anionic interference (less than 10% variation) in organic wastewater treatment. This study provides a technical reference and theoretical foundation for enhancing biochar activation of PS in the removal of organic pollutants from aquatic and terrestrial environments. [ABSTRACT FROM AUTHOR]

[Display omitted] • Loading humic acid strengthened activation performance of biochar for persulfate; • Degradation held a pivotal position in polycyclic aromatic hydrocarbons remediation; • Polycyclic aromatic hydrocarbons degraded into less toxic intermediates by radicals; • The pathways for naphthalene, pyrene and benzopyrene degradation were investigated. The remediation for polycyclic aromatic hydrocarbons contaminated soil with cost-effective method has received significant public concern, a composite material, therefore, been fabricated by loading humic acid into biochar in this study to activate persulfate for naphthalene, pyrene and benzo(a)pyrene remediation. Experimental results proved the hypothesis that biochar loaded humic acid combined both advantages of individual materials in polycyclic aromatic hydrocarbons adsorption and persulfate activation, achieved synergistic performance in naphthalene, pyrene and benzo(a)pyrene removal from aqueous solution with efficiency reached at 98.2%, 99.3% and 90.1%, respectively. In addition, degradation played a crucial role in polycyclic aromatic hydrocarbons remediation, converting polycyclic aromatic hydrocarbons into less toxic intermediates through radicals of · SO 4 -, · OH, · O 2 –, and 1O 2 generated from persulfate activation process. Despite pH fluctuation and interfering ions inhibited remediation efficiency in some extent, the excellent performances of composite material in two field soil samples (76.7% and 91.9%) highlighted its potential in large-scale remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • BC350 released orthophosphates via diffusion, while BC450 and BC550 via dissolution. • N, K, and DOC were released from biochar by a surface wash-off controlled process. • Nutrients released from BC450 and BC550 could stimulate the seed shoot length. • BC450 and BC550 exhibited a good potential as long-term slow-release N and P fertilizers. Food waste anaerobic digestion requires proper utilization of solid digestate, and pyrolysis emerges as an effective method to produce nutrient-rich biochar. This study investigated the leaching characteristics and speciation changes of nutrients in food waste digestate (FWD)-derived biochar pyrolyzed at 350 °C (BC350), 450 °C (BC450), and 550 °C (BC550). BC350 featured inorganic nitrogen, while BC450 and BC550 contained elevated organic nitrogen. Nitrogen, potassium, and dissolved organic carbon were released via a quick surface wash-off process. Polyphosphates prevailed in BC350 and leached through a fast diffusion-controlled process. BC450 and BC550 were dominated by Ca/Mg orthophosphates and released via a slow dissolution-controlled process. Leachates from BC450 and BC550 stimulated the shoot length of wheat seeds. After 5 leaching cycles, there were more aromatic dissolved organics, and BC450 and BC550 exhibited higher abundance of C-N and O-P-O. Overall, pyrolysis of FWD at 450 °C and 550 °C shows potential in producing slow-release biochar fertilizers for resource recycling. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Mn-N co-doped biochar for removing BPA (351 mg/g) was prepared. • High specific surface area was helpful to reveal more Mn-N adsorption sites. • The main mechanisms were pore filling, hydrophobic effect and π-π-EDA interaction. • DFT proved that nitrogen configurations and manganese promoted adsorption. A novel porous manganese and nitrogen co-doped biochar (Mn-N@SBC) was synthesized via one-step pyrolysis, utilizing loofah agricultural waste as the precursor and NaHCO 3 as the activator. The behavior of bisphenol A adsorbed on Mn-N@SBC was evaluated using static batch adsorption experiments. Compared to direct manganese-nitrogen co-doping, co-doping based on NaHCO 3 activation significantly increased the specific surface area (231 to 1027 m2·g−1) and adsorption capacity (15 to 351 mg·g−1). Wide pH (2–10) and good resistance to cation/anion, humic acid and actual water demonstrated the robust adaptability of Mn-N@SBC to environmental factors. The significantly reduced specific surface area after adsorption, adverse effects of ethanol and phenanthrene on the removal of bisphenol A, and theoretically predicted interaction sites indicated the primary adsorption mechanisms involved pore filling, hydrophobicity, and π-π-electron-donor–acceptor interaction. This work presented an approach to create high-efficiency adsorbents from agricultural waste, offering theoretical and practical guidance for the removal of pollutants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biochar and zeolite could reduce GHGs emissions during kitchen waste composting. • All treatment groups reduced potential core microbe abundance associated with GHGs. • The N 2 O metabolic pathway was constructed through KEGG and q-PCR. • Biochar and zeolite regulated nitrogen function genes to inhibit denitrification. Aerobic kitchen waste composting can contribute to greenhouse gas (GHGs) emissions and global warming. This study investigated the effects of biochar and zeolite on GHGs emissions during composting. The findings demonstrated that biochar could reduce N 2 O and CH 4 cumulative releases by 47.7 %and 47.9 %, respectively, and zeolite could reduce the cumulative release of CO 2 by 28.4 %. Meanwhile, the biochar and zeolite addition could reduce the abundance of potential core microorganisms associated with GHGs emissions. In addition, biochar and zeolite reduced N 2 O emissions by regulating the abundance of nitrogen conversion functional genes. Biochar and zeolite were shown to reduce the impact of bacterial communities on GHGs emissions. In summary, this study revealed that biochar and zeolite can effectively reduce GHG emissions during composting by altering the compost microenvironment and regulating microbial community structure. Such findings are valuable for facilitating high-quality resource recovery of organic solid waste. [ABSTRACT FROM AUTHOR]

[Display omitted] • LS/PEI@biochar, an ideal biocarrier for immobilized bacteria, was prepared. • The removal efficiency of NH 4 +-N, Ca2+, and PO 4 3--P were 94.71, 80.68, and 76.67 %. • The biofilm reactor showed good performance in utilizing low-carbon sources. • The ecological restoration mechanism of oligotrophic water was elaborated. • Biofilm reactor was suitable for oligotrophic water complex pollutants treatment. The removal of complex pollutants from oligotrophic water is an important challenge for researchers. In this study, the HCl-modified loofah sponge crosslinked polyethyleneimine loaded with biochar (LS/PEI@biochar) biofilm reactor was adapted to achieve efficient removal of complex pollutants in oligotrophic water. On the 35 d, the average removal efficiency of chemical oxygen demand (COD), ammonia nitrogen (NH 4 +-N), calcium (Ca2+), and phosphate (PO 4 3--P) in water was 51, 95, 81, and 77 %, respectively. Additionally, it effectively used a low molecular weight carbon source. Scanning electron microscopy (SEM) results showed that the LS/PEI@biochar biocarrier had superior biofilm suspension performance. Meanwhile, analysis of the biocrystals confirmed Ca2+ and PO 4 3- removal through the generation of CaCO 3 (calcite and vaterite) and Ca 5 (PO 4) 3 OH. This study demonstrated that the system has great efficiency and application prospect in treating oligotrophic water on the laboratory scale, and will be further validated for practical application on large-scale oligotrophic water. [ABSTRACT FROM AUTHOR]