Search

The rapid emergence of unique types of pollutants is of worldwide concern owing to their deleterious effects on living beings. Mitigating pollution in the way of sustainability is the need of the hour to protect the existing environment from degradation. In this regard, eco-friendly biochar was prepared from the intact plant of Eichhornia crassipes (water hyacinth) without neglecting the roots, stems, leaves, and flowers and assessed for its ammonium removal efficiency in the study. Twelve biochars of two categories, viz., treated and normal, were produced under two different pyrolysis temperatures of 300 °C and 500 °C and three residence times of 30, 45, and 60 min. The adsorption experiments were conducted as batch studies in triplicate to examine the impacts of multiple adsorption-inducing factors in biochar. The maximum ammonium removal efficiency of about 83% was shown by the alkali-activated biochar produced at a higher temperature of 500 °C with a longer residence time of 60 min. The biochar showing higher ammonium adsorption was characterized by Scanning Electron Microscopy and Fourier Transform Infra-Red spectroscopy, which revealed the increased number of pores and the presence of C–O, OH, and C O groups that altogether aided the adsorption process. The kinetic study conducted with contact times of 30, 60, and 90 min showed that the linear regression values were >0.999 for the pseudo-second-order kinetic model, which revealed that the ammonia sorption of Eichhornia biochars followed a second-order mechanism of chemisorption. Synthesized biochar has shown significant efficacy in ammonia adsorption, making it worthwhile in applications where ammonia removal is necessary, particularly in wastewater treatment besides agriculture and air purification. [Display omitted] [ABSTRACT FROM AUTHOR]

Currently, the production of nanobiochar (n-BC) using ball milling is a promising and cost-effective method. Studies concerning the physicochemical properties of bulk biochar (b-BC) in relation to pyrolysis temperature, various feedstocks or types of carrier gas have been thoroughly investigated. However, there is a lack of information on how the mentioned conditions determine the properties of the obtained n-BCs. In this study, b-BCs produced from different feedstocks (willow (WL), sewage sludge (SSL), rice husk (RH) and oilseed rape (OSR)), temperatures (450–750 °C) and carrier gases (N 2 or CO 2) were ball-milled to produce n-BCs. The specific surface area (S BET), elemental composition (C, H, N, O), morphology (SEM), functional groups (FT-IR), and crystalline and amorphous nature of the carbon (RAMAN) were determined. The size of n-BCs depended on the feedstock used (particles ranged from 30 to 87.9 nm). The type of feedstock mostly determined the properties of n-BCs. The most visible differences between n-BCs and b-BCs were observed for surface properties and C content. For all n-BCs, an S BET increase was observed after ball milling, which may enhance the adsorption potential of biochar. The most intense S BET changes were noted for WL-derived n-BCs obtained at 450 °C (increase from 7.2 to 146.3 m2/g) and at 750 °C (increase from 3.9 to 160.8 m2/g) and for RH-derived n-BCs produced at 550 °C (increase from 3.7 to 158.6 m2/g). The C content decreased for n-BCs produced from plant biomass (WL, RH and OSR) and increased (from 20 to 28%) for n-BCs derived from sewage sludge (SSL). Other physicochemical properties mainly depended on the feedstock used for biochar production. [Display omitted] • Most of the properties of n-BCs differ from the properties of b-BCs. • The type of feedstock was the main factor affecting most of the properties of n-BC. • The decrease in particle size leds to increased aromaticity and elevated polarity of the n-BCs. • Ball milling resulted in a pH decrease and an increase in the electrical conductivity (EC) of the n-BCs. [ABSTRACT FROM AUTHOR]

Advanced persulfate oxidation (AOPs) is a promising method for the degradation of organic pollution, but the preparation of economic, high activity, and low toxicity non-heterogeneous catalysts is still difficult. In this study, a novel nanoscale zero-valent iron composite (nZVI@NBC) supported by biochar with nitrogen doping was prepared, applying activated peroxydisulfate (PDS) to degrade 2,4-dichlorophenol (2,4-DCP). Results demonstrated that nZVI@NBC/PDS system has a 11.8-fold higher degradation k obs of 2,4-DCP than the undoped nitrogen sample, and 2,4-DCP was entirely removed within 60 min. Through different analytical techniques, singlet oxygen (1O 2) was the leading reactive oxygen species (ROS), and graphitic and pyridine nitrogen were the key nitrogen species to produce 1O 2. In addition, electrochemical texts and DFT calculation confirmed that nitrogen doping increased the catalyst's electrical conductivity, so that the 2,4-DCP adsorbed to the [nZVI@NBC-PDS] sub-stable complex was direct oxidation by electron transfer. Furthermore, the nZVI@NBC/PDS system exhibited high selectivity in the co-presence of inorganic anions and other pollutants and possessed excellent 2,4-DCP removal rates (>95 % in pH 3–9). The column experiments demonstrated the high potential of nZVI@NBC to remove 2,4-DCP in groundwater. The mechanism of activation of PDS and degradation of organic contaminants by nZVI@NBC, provide a new approach for the remediating the groundwater pollution. [Display omitted] • The nZVI@NBC exhibited stable and efficient activation effect of PDS. • The degradation efficiency of 2,4-DCP can reach nearly 100% in 60 min. • Non-radical 1O 2 was the primary reactive species for 2,4-DCP degradation. • The nZVI@NBC/PDS system degraded 2,4-DCP effectively in the wide pH range of 3–9. • The electron transfer mechanism of the non-radical pathway has been elucidated. [ABSTRACT FROM AUTHOR]

Due to the importance and economic value of gold in various applications, recovering gold from waste streams like tailings and industrial wastewater is essential. Biochar with a high surface area and porosity is considered a potential low-cost adsorbent for gold reclaiming from aqueous media. Therefore, this study aims to develop a high-quality biochar with excellent physicochemical properties to efficiently remove gold from aqueous media. To accomplish this, biochar was obtained from pyrolysis of ironbark (IB) biomass at 500 °C which has a surface area of 493.79 m2/g. Subsequently, the biochar was investigated for adsorption of gold from aqueous media, which exhibited a maximum adsorption capacity of 858 mg/g. Isotherm results showed that the adsorption of gold by biochar followed the Langmuir model, indicating monolayer adsorption. Further, response surface methodology (RSM) and an artificial neural network (ANN) combined with the Salp Swarm Algorithm (SSA) were used to analyze the generated results (ANN-SSA). The RSM prediction model fit was adequate (R2 = 0.99). However, comparing the statistical data revealed that ANN-SSA outperformed RSM in predicting experimental results. Overall, this study suggested that biochar derived from IB biomass could be used as a potential adsorbent to recover gold from an aqueous solution. This article presents a unique and innovative study on the utilization of ironbark biochar for the purpose of gold adsorption. [Display omitted] • A novel biochar produced from ironbark was investigated for Au adsorption. • The biochar achieved a maximum Au adsorption of 858 mg/g under optimized conditions. • ANN model showed a better Au adsorption prediction compared to the RSM model. • Physisorption and electrostatic attraction were the dominant Au adsorption mechanism. • Au adsorption followed the Langmuir model, indicating a monolayer surface adsorption. [ABSTRACT FROM AUTHOR]

To achieve a closed nutrient cycle and more sustainable food production, enhanced nutrient recycling in the agri-food system is a necessity. Pyrolysis is an emerging technology to recycle the nutrient content of sewage sludge. The produced biochar can be used to reduce the need for mineral fertilizers; in addition, pyrolysis can also handle potential pollutants such as microplastics and pathogens present in sewage sludge. In this research, a life cycle assessment (LCA) was carried out to determine the environmental impact of sewage sludge pyrolysis as an alternative to current practices of two different cases of sewage sludge treatment in two municipalities in Sweden. The results indicated that avoiding mineral fertilizer production by using biochar has a significant influence on the environmental benefits. Furthermore, it showed that an integrated system of anaerobic digestion followed by pyrolysis could perform as the most environmental-friendly option for sewage sludge treatment with a lower risk of transferring pollution to the soil. [Display omitted] • Life cycle assessment has been performed to compare the current practice of sewage sludge treatment with alternative of pyrolysis. • Midpoint impact assessments results have been combined with analysis of other factors such as contamination transfer risk to soil, carbon sequestration and legislative aspects. • Avoided mineral fertilizer production shows a significant contribution to the environmental benefit of treatment methods. • Results show that pyrolysis could be an environmental preferable treatment for sewage sludge. • Future research should focus on innovative solutions of sewage sludge treatment which satisfy environment and human health simultaneously. [ABSTRACT FROM AUTHOR]

Magnetite nanoparticles were deposited on Douglas fir biochar (Fe 3 O 4 /DFBC) using aqueous, NaOH-induced chemical co-precipitation from Fe2+/Fe3+ salt solutions. Fe 3 O 4 /DFBC was used to remediate As(V)-contaminated water. Kinetics and isotherms were studied. pH 5 was selected as the optimized pH due to low iron leaching and closeness to groundwater pH. Adsorption equilibrium was reached after 3 h, 2 h, and 1 h for 0.5, 5, and 50 mg/L initial As(V) concentrations, respectively. Adsorption was endothermic, and the Langmuir capacity was 6.33 mg/g at 25 °C. Ionic strength, impacts of Fe 3 O 4 /DFBC particle size, and competitive ion/molecule effects during As(V) adsorption were studied. Continuous-flow fixed-bed column breakthrough studies performed at 0.5, 5, and 50 mg/L of As(V) at pH 5 exhibited maximum capacities of 3.47, 3.99, and 3.72 mg/g, respectively. Aqueous potassium phosphate was used successfully for column regeneration. Fe 3 O 4 /DFBC was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Mössbauer spectroscopy before and after As(III) and As(V) adsorption. Mössbauer found the "Fe 3 O 4 " was composed of several phases. A key target was the study of simultaneous toxic As(III) adsorption and its transformation to As(V) from pH 1–13. The highest removal of As(III) and oxidized As(V) was obtained at pH 3. The relationship between iron leaching and pH was investigated and the pH-dependent surface adsorption was monitored using X-ray photoelectron spectroscopy (XPS) from pH 1 to 13. One goal of this study was to enhance the understanding of the adsorption characteristics needed for initial scaling of a treatment facility that can efficiently remediate arsenic-contaminated wastewater. Experiments were conducted using batch and fixed bed continuous flow columns to optimize adsorption process parameters under various circumstances and solution matrices. Another goal was to further establish the surface structures of the chemisorbed arsenates versus pH. [Display omitted] • As(III) can be oxidized to As(V) in anoxic conditions when adsorbed. • Solution effects, dose optimizations, column separations, and Fe2+/3+ leaching versus pH were studied during As(V) removal. • AsO 4 3− adsorption capacity was 6.33 mg/g at 25 °C. • Redox transformation of As(III) to As(V) on Fe 3 O 4 /DFBC was studied from pH 1 to 13. • Mössbauer spectroscopy and pH-dependent XPS aided detailed mechanistic understanding. [ABSTRACT FROM AUTHOR]

Recycling of phosphorus (P) from waste streams such as sewage sludge to agriculture is essential in order to ensure future food security. Land application of sewage sludge is controversial due to its content of pollutants, such as heavy metals and toxic organic compounds. Pyrolysis is a technology that can eliminate harmful contaminants while enabling the recycling of P in the sludge. Organic pollutants are degraded during pyrolysis, while most of the P remains and approximately 40 % of the carbon is retained in a stable form in the biochar. When performing pyrolysis at a temperature of around 800 °C or more, cadmium is evaporated and can be separated from the biochar. Electricity-driven pyrolysis facilitates this by means of easier temperature control. The aim of the present study was to undertake a Life Cycle Assessment (LCA) to evaluate the environmental impacts of high-temperature electricity-driven pyrolysis of sewage sludge, including the separation of cadmium, and field application of sludge biochar as compared with sewage sludge storage and field application. The results showed that pyrolysis can offer a more climate-friendly solution due to avoided greenhouse gas emissions from the sludge and to carbon sequestration of the biochar. However, field application of untreated sludge resulted in a higher application of nitrogen (N) and more plant-available P. Agricultural modelling tools indicated that this produces higher crop yields than biochar application. In the LCA model, higher crop yields lead to savings in land use and water consumption as the higher yields can replace other crop production. The lower plant availability of biochar P implies a possible risk of lower yields when the P application is restricted based on total P, and a risk of greater P loss with soil erosion to the environment. Overall, the present study stresses the importance of including the long-term agronomic impacts of sludge and biochar field application in LCAs, and highlights the trade-offs that need to be considered in decision-making regarding the implementation of pyrolysis technology. [Display omitted] • LCA of electricity-driven pyrolysis, with temperature control for cadmium removal. • Pyrolysis benefits the climate through C sequestration and reduced GHG emissions. • Pyrolysis reduces human toxicity due to removal of cadmium and organic chemicals. • Agricultural modelling suggests higher crop yields after sewage sludge application. • Low P-availability in biochar risks higher P loss with erosion and lower crop yield. [ABSTRACT FROM AUTHOR]

In today's technologically advancing and increasingly urbanized world, the search for new materials like biochar has become crucial to address environmental challenges such as pollution and agricultural needs. Biochar, derived from pyrolyzed biomass, offers a sustainable solution for soil improvement and pollution control. This review explores biochar's diverse applications in waste management, pollution control, and agriculture, emphasizing its potential for promoting sustainability and circular economy practices, while also discussing emerging applications like supercapacitors. Compared to previous works, this review offers a comprehensive examination of biochar's diverse applications and its potential for future trends in environmental sustainability. [Display omitted] • A review was conducted on the use of biochar for environmental remediation purposes. • Biochar plays a crucial role in enhancing soil health and boosting crop productivity. • Future research in biochar is poised to explore unconventional applications. • Biochar holds significant potential for addressing global. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainability and circularity, this study aimed to develop a multi-purpose biorefinery pipeline using extracts from the green seaweed Codium sp. and transforming its post-extracted biomass into biochars, emphasizing holistic resource utilization. Five extracts from Codium sp. were evaluated, testing their antioxidant potential, cytotoxicity, photoprotective effects, anti-inflammatory activity, and inhibitory capabilities against enzymes hyaluronidase, collagenase, and elastase. The ethyl acetate extract showed the highest values in the ORAC assay, indicating antioxidant activity. However, no relevant antioxidant activity was observed in the FRAP and DPPH assays for the other extracts. The hydroethanolic extract exhibited the best anti-enzymatic capacity, inhibiting elastase by 88% at 200 μg/mL. It also demonstrated a photoprotective effect and reduced ROS production (30%) induced by UVB exposure. The hydroethanolic and ethanol extracts significantly reduced the concentration of the tumour necrosis factor-alpha (TNF-α) in response to LPS stimulation, indicating anti-inflammatory activity. The hydroethanolic post-extracted biomass was converted into biochars using conventional slow pyrolysis, hydrothermal carbonization (HTC), and acid-mediated carbonization (AMC). The biochars contained 56–75% C and 22–30% O and the one synthesized by HTC had the highest textural development. The biochar obtained by AMC showed better performance in improving soil water retention capacity, suggesting that acid surface chemistry plays a more significant role than porosity. The Codium sp. extracts and biochars produced from the post-extracted biomass have demonstrated potential as a source of valuable bioactive compounds and biomaterials for a circular economy framework and biorefinery pipeline with wide-ranging applications. [Display omitted] • Sustainable exploitation of Codium sp. within a bio-circular economy concept. • Extract bioactives with antioxidant, anti-inflammatory and photoprotective properties. • Seaweed by-products yield biochar by conventional and advanced processes. • Biochars from acid-mediated carbonization enhanced soil water retention capacity. [ABSTRACT FROM AUTHOR]

The utilization of agricultural solid biowastes is essential for resource saving and bioenergy conversion. By this way, the demand of industrial furnace for biomass would be compensated, and the energy structure would also be greener. Among them, torrefaction is a hopeful technology for solid biofuel production. This study investigates the grinding performance of torrefied biochar to achieve the grindability and component variation analysis of torrefied agricultural wastes for fluidized bed boiler, and thus realize pulverized biochar injection for industrial application. Totally crystallinity index (CrI), average particle size distribution, energy input for grinding process, component analysis, and elemental carbon state are adopted and analyzed around Hardgrove grindability index (HGI). The values of HGI are in the range of 45–120, 45–105, 60–120, and 60–135, respectively. The results indicate that torrefaction is conducive for biochar properties upgrading, especially for a higher temperature, and thus contributes to a higher HGI, lower particle size and grinding energy input, as well as better elemental carbon state. The produced powder from torrefied biochar is highly correlated to torrefaction temperature and biochar component, and thus leads to an excellent industrial application potential. Overall, this study is conducive for the agricultural biowastes conversion and solid biofuel production. [Display omitted] • The grindability of four agricultural solid biowastes were analyzed. • Torrefaction is conducive to achieving biochar grindability improvement. • Grindability is correlated to crystallinity index and grinding energy input. • A higher torrefaction temperature is conducive for biochar powder size reduction. • Biochar component and carbon state are correlated to grindability. [ABSTRACT FROM AUTHOR]

Biochar has demonstrated the potential in mitigating pollutant gaseous emission during composting. However, little is known about the difference among biochars derived from different plant feedstocks on the critical genes' expression and microbial communities' succession for gaseous emissions. In this study, the effects of biochar (from wood chips, cornstalks, and rice husks) on gaseous emissions during chicken manure composting were investigated. Environmental factors, bacterial communities, and functional genes related to CH 4 , N 2 O, NH 3 , and H 2 S emissions were analyzed to reveal the reduction pathways of different biochar amendments during composting. Results showed that all biochar treatments improved the seed germination index of the compost from unmature (55.74%) to mature (70.28–75.23%). The CH 4 , N 2 O, NH 3 , and H 2 S emissions from all biochar-treated composts were reduced by 18.93–27.47%, 35.74–52.82%, 1.26–36.38%, and 8.57–24.14%, respectively, and the cornstalk biochar had the highest emission reduction performance. Temperature, pH, and NH 4 + were the major environmental factors that affected Lactobacillus and Bacillus activities, which critically influenced the CH 4 , N 2 O, NH 3 , and H 2 S emissions during composting. Furthermore, cornstalk biochar mainly improved pmoA for CH 4 reduction, whereas wood chip biochar increased amoA for NH 3 oxidation. Rice husk biochar mostly decreased nirS and nirK and increased norB , narG , and nosZ during N 2 O reduction. Cornstalk biochar also increased dsrB and decreased aprA during H 2 S reduction. Overall, cornstalk biochar was determined to be an optimal additive for simultaneously improving compost maturity and reducing gaseous pollutant emissions during chicken manure composting. This study verified the mechanisms of three plant derived biochars in pollutant gas control in composting, and thus provided evidence for facilitating the sustainable development of composting technologies. [Display omitted] • Cornstalk biochar emitted the lowest CH 4 , N 2 O, NH 3 , and H 2 S in composting. • Temperature, pH, and NH 4 + regulated Lactobacillus and Bacillus to reduce emissions. • Cornstalk biochar increased pmoA and decreased mcrA abundances for lower CH 4 emissions. • Rice husk biochar reduced nirS and nirK and increased norB , narG , and nosZ to lower N 2 O. • Cornstalk biochar increased dsrB and decreased aprA abundances for lower H 2 S emissions. [ABSTRACT FROM AUTHOR]

Biochar is an environment-friendly immobilizing agent and performs better in remediating soil cadmium (Cd) along with compost. However, little attention has been paid to the effects of the intrinsic properties of biochar in combination with compost on the phytoavailability and translocation of legacy Cd (Cd L) and newly introduced Cd (Cd N) in the soil-lettuce-human system. Therefore, in this study, four biochars originated from pig manure, sewage sludge, wood chip, and rice husk were produced into mm/μm/nm-particles, which was combined with compost respectively. The impact of the different particle-size biochar compost blends (BCCM) on the translocation, bioaccessibility and bioavailability of Cd L and Cd N was investigated through applying enriched isotope tracing and Caco-2 cell model. The results showed that the lowest labile Cd L/N (ECd L/N) values were found in nm-BCCM by converting exchangeable Cd into other unusable Cd forms. nm-BCCM has a significant reduction in Cd L/N uptake, accumulation, and translocation by lettuce a s nm-BCCM increased the cell wall percentages and decreased the solution components of Cd L/N in the root. Despite almost immobilizing agents did not decrease the bioaccessibility and bioavailability of Cd L/N , the lower bioaccessible and bioavailable Cd L/N contents imply nm-BCCM can guarantee the public was minimally exposed to the risk of Cd. These results suggested that combining nm-biochar and compost had greater potential to reduce Cd L and Cd N translocation and absorption in complex environmental systems. [Display omitted] • Enriched isotope tracing combined with Caco-2 cell model for assessing Cd pollution. • nm-BCCM reduced soil labile Cd L/N values regardless of the raw materials of biochar. • Cd N had a greater root to shoot transport ability than Cd L. • nm-BCCM can minimize Cd L/N transfer and uptake in the soil-lettuce-human system. [ABSTRACT FROM AUTHOR]

Medium-chain fatty acids (MCFAs) are value-added products that can be produced through two-stage fermentation, where using sewage sludge as substrate contributes to achieving dual benefits of sludge management and low-carbon MCFAs production. In this paper, the promotion effect of biochar on MCFAs production was explored, and biochars derived from different biomass were added to reveal the impact of biochar type on MCFAs production from sewage sludge during the two-stage fermentation process. Results showed that biochar did enhance MCFAs production from sludge fermentation. The highest MCFAs accumulation (254.15 mmol C/L) was obtained in the coconut shell-derived biochar (CC) added group with an increase of 30.37%, and the caprylate accounted for up to 43.92% of total produced MCFAs. CC was most conducive to facilitating electron transfer and carbon conversion in the chain elongation (CE) process. The microbial analysis demonstrated that biochar additives enhanced the microbial diversity, together with the abundance of functional microorganisms. The cornstalk-derived biochar was more favorable for acidification (AC) microbes. In contrast, the CE microbes were ideally enriched by CC and rice stalk-derived biochar (RS), accompanied by the suppressed AC microbes during the CE process. Functional enzyme analysis indicated that CC contributed to breaking the rate-limiting step in the dominant metabolic pathway, stimulating MCFAs production by strengthening the dominant pathway in CE pathways. [Display omitted] • Biochar could promote MCFAs production from sewage sludge. • Biochar derived from different biomass had various effect on MCFAs production. • Biochar from coconut shell promoted product formation and electron transfer. • Corn stalk-derived biochar was more favorable for AC microbes to colonize. • Biochar type did not change the dominant status of FAB pathway in CE pathways. [ABSTRACT FROM AUTHOR]

Lightweight concrete is widely used in non-structural components of buildings, e.g., partition wall bricks. Most current lightweight concretes engage Portland cement and lightweight aggregates. In this study, lightweight concretes based on reactive magnesia cement (RMC) and high amount of biochar aggregates (up to 508 kg/m3, 61 vol% of the concrete) are developed. The new material demonstrates the ability to sequestrate massive amounts of CO 2 from ambient air, and thus has the potential to be used for greener non-structural applications. The CO 2 sequestration during curing under high-concentration CO 2 (10 %), which is mainly via the RMC carbonation, is determined by acid digestion. The CO 2 sequestration during service under ambient CO 2 concentration (0.1%, or 1000 ppm), which is via the continued carbonation of RMC and the adsorption of biochar, is determined by monitoring the removal of CO 2 in situ; particularly, the CO 2 sequestrations by the RMC and the biochar are determined separately. The effect of varying biochar content and CO 2 curing time on the overall CO 2 sequestering ability of the concrete are studied, together with the variation of the local CO 2 sequestration with carbonation depth in the concrete. Based on the experimental results, the new concretes are seen to achieve adequate mechanical properties for non-structural application. They can permanently sequestrate a significant amount of CO 2 during the curing phase (0.2–0.3 g per gram RMC), and constantly sequestrate noticeable amounts of CO 2 during the service stage (1–12 mg per gram RMC, 1 mg per gram biochar). The incorporation of porous biochar not only decreases the material density, but also improves the RMC carbonation by accelerating CO 2 penetration, while the RMC barely influences the biochar adsorption. However, the RMC carbonation ability permanently vanishes with curing age, whilst the biochar adsorption decreases marginally with the curing age. [Display omitted] • Lightweight concrete developed with reactive MgO cement and high-dosage biochar. • Substantial CO 2 sequestration under curing (10% CO 2) and ambient service (0.1% CO 2). • Separately quantified CO 2 sequestration by MgO and biochar with new methodology. • Quantified relationship between CO 2 sequestration and biochar content, age, humidity. • Discovered unconventional depth-dependency of RMC carbonation induced by biochar. [ABSTRACT FROM AUTHOR]

Chain elongation (CE) is a promising technology that can produce medium-chain fatty acids (MCFAs) from sewage sludge, reaching the dual benefits of waste management and clean energy production. The feasibility of using biochar to enhance CE efficiency was examined in this study, where the underlying promoting mechanisms and optimal biochar dosage were also simultaneously explored. Biochar improved the carbon conversion and electron transfer efficiency of CE. The highest caproate concentration (3347.95 mg/L) occurred in the group with 10 g/L biochar addition, and caprylate was most accumulated (612.36 mg/L) when biochar dosage was 20 g/L. The electroactive genera positively related to MCFAs (e.g., norank_f__JG3 0-KF -CM45 and Acetobacterium) were noticeably enriched by low dosage, but the acidification genera proliferated better under excessive dosage. The different MCFAs production induced by varied biochar dosages was closely related to the genera Dysgonomonadaceae. The strengthened dominant CE pathways, FAB, might account for the promoted MCFAs production. [Display omitted] • Biochar accelerated substrate utilization and MCFAs production from sewage sludge. • Low biochar dosage enriched CE bacteria and enhanced their syntrophic metabolism. • Acidification bacteria proliferated better than CE bacteria under excessive biochar. • Dysgonomonadaceae was tightly related to varied MCFAs caused by biochar dosage. • Biochar reinforced the dominant status of the FAB metabolic pathway. [ABSTRACT FROM AUTHOR]

The safety and feasibility of directly treating hyperaccumulators with heat is constrained by the substantial presence of volatile heavy metals (HMs) within these plants. The combination of acid pretreatment and heat treatment holds potential for both energy recovery from hyperaccumulators and the transfer of their HMs to specific phases. This study aimed to reveal not only the pyrolysis and gasification kinetics and products of arsenic-hyperaccumulator (Pteris vittate L.) (PV) pretreated with HCl or H 3 PO 4 but also the migration, distribution, and leaching of HMs in products and interaction between HMs and minerals. The HCl-pretreated PV exhibited similar decomposition behaviors and mechanisms to the control PV, with a gradual decrease in overall activation energy (E m). In contrast, H 3 PO 4 changed the behaviors and increased E m. The relative yield of syngas and biochar rose with increased acid concentration. Given the pyrolysis and gasification-induced volatile products released at 550, 750, and 950 °C, HCl increased the relative yield of aromatic compounds and reduced the formation of ring-opening products compared with PV. Compared with HCl, H 3 PO 4 increased the emissions of aromatic compounds and ketone. HCl promoted the loss of HMs, including accelerating their volatilization from the solid phase and increasing their leaching concentration from the biochar. HMs were mostly retained in the H 3 PO 4 -pretreated PV biochar with a low leachable rate, gradually decreasing with the rising temperature. The maximum energetic performance and HM immobilizations were optimized using artificial neural networks. This study revealed plausible reaction pathways and immobilization mechanisms, involving the interactions between minerals and HMs due to Cl or P introduced by the acid pretreatment. Overall, our findings provide new insights into the pyrolysis and gasification behavior of acid-pretreated hyperaccumulator. In particular, the H 3 PO 4 pretreatment not only produced high-yield, high-quality bio-oil products with low HM content but also retained the HMs in the biochar. [Display omitted] • Composition, relative yields, and temperature dependency of volatiles were revealed. • HCl-pretreated PV promoted the HMs volatilization and leaching from solid phase. • H 3 PO 4 -pretreated PV retained most HMs in the biochar with a low leachable rate. • Interactions among HMs, minerals, and acid pretreatment were revealed. • Energetic performance and HM immobilizations were optimized via neural networks. [ABSTRACT FROM AUTHOR]

Upcycling the solid biomass waste into bio-oil and biochar are promising solutions to mitigate environmental pollution caused by solid waste and offer value-added products with tremendous applications, simultaneously. The bio-oil and biochar could be considered as excellent alternatives to the petroleum-based asphalt, however, the application potential of bio-oil and biochar could be compromised, due to the high oxygen content of the bio-oil and presence of heavy metals in the biochar. In this study, biochar modified asphalt (BMA) and biochar modified bio-asphalt (BMBA) were successfully developed using wood waste as feedstock. 16 polycyclic aromatic hydrocarbons (PAHs) and 6 heavy metals were mainly assessed by adsorption characteristics using prepared samples. The major results demonstrates that the concentrations of Cd2+, Cr3+, Cu2+, and Ni2+ elements leached from bio-asphalt was within the acceptable levels (2 mg/L) regarding environmental pollution. And adsorption ability of bio-asphalt was selective and that the ability of BMBA in reducing heavy metals concentration was better than BMA. Major parameters including rainfall time and solar irradiation time could slightly affect the toxicity of PAHs leached from bio-asphalt in the road runoff. Biochar and bio-oil were promising additives for petroleum-based asphalt given its environmental benefits and sustainable properties. [Display omitted] • 16 PAHs and 6 heavy metals leaching toxicity of bio-asphalt are investigated. • The heavy metal adsorption ability of bio-asphalt is selective. • Rainfall time and irradiation time increase PAHs leaching toxicity of bio-asphalt. • Biochar protects asphalt from heavy metal and PAHs pollution. • There are synergistic effects of rainfall and irradiation on heavy metals and PAHs in bio-asphalt leachate. [ABSTRACT FROM AUTHOR]

Biochar has exceeded expectations for immobilizing heavy metals (HMs), but the potential ecological risks of its long-term burial in soil limit its practical application on a large scale. To address this challenge, a novel separable water-hardened magnetic composite biochar sphere (WMBCS) was prepared and applied to remediate agricultural soils contaminated with Cd, Pb, and As. The first application of WMBCS is simultaneously effective in removing Cd (3.2–12.7%), Pb (3.3–13.1%), and As (5.0–25.6%) from soil, and the removal rates are enhanced with increasing soil moisture, application dose and incubation time. WMBCS is more efficient for removing Cd and Pb in mildly contaminated alkaline soils than in heavily contaminated acidic soils. Compared with other regeneration methods, shaking and ultrasound-assisted EDTA-2Na efficiently elutes HMs with a dissolution efficiency of over 75% within 4 h, accompanied by the lowest rate of mass loss (7.6%) and Fe leaching (475.1 mg kg−1). After 5 rounds of successive cyclic remediation, WMBCS exhibits high adsorption efficiency (26.5–30.6% for Cd, 25.4–30.2% for Pb, and 30.2–41.0% for As), magnetic separation efficiency (98.8–99.8%) and regeneration efficiency (92.3–95.4%). The main mechanisms involved in the adsorption and regeneration of WMBCS include ion exchange and chelation. WMBCS is an economical and eco-friendly material with vast unexplored potential for use in agriculture. [Display omitted] • Green adsorbents effectively remove Cd, Pb and As from contaminated soil. • EDTA-2Na is effective for heavy metal desorption and WMBCS regeneration. • Ultrasound assistance could accelerate the WMBCS regeneration. • Regenerated WMBCS exhibits excellent adsorption and magnetic separation capabilities. • WMBCS removes heavy metals and regenerates through physical and chemical effects. [ABSTRACT FROM AUTHOR]

Pyrolysis could be one of the promising ways for polyethylene terephthalate (PET) waste-based char production, while the adherence environmental persistent free radicals (EPFRs) brought the risks for the wide application. Co-pyrolysis was employed as the potential way to reduce the EPFRs and improve the char quality simultaneously with the introduction of sewage sludge (SS), and the optimization reaction conditions and the relative mechanisms were proposed in this work. EPFRs in PET-based char were found to decrease from 1.07 × 1018–4.84 × 1018 spins·g−1 to 2.17 × 1017–4.90 × 1017 spins·g−1, with 38.86–48.55% reduction at the mass ratio of 1:1 (PET:SS). The corresponding activation energy decreased by 78.83% with 30.93% higher biochar yield rate due to the synergistic effects. Co-pyrolysis facilitated the decomposition of benzoic acid and its derivatives by enhancing the cleavage of oxygen-containing functional groups and led to the binding of nitrogen with more pyrolysis intermediates, resulting in a reduction of precursors for oxygen/oxygenated-carbon centered radicals. More phenyl radicals were polymerized into carbon-centered radicals through hydride transfer and crosslinking in the mixed system. The additive of SS promoted the aromatization degree, enhanced the defect and pore structure of the biochar, and led to a 43.62-fold increase in the surface area of PET-based char at 400 °C. This work provides a potential approach to reduce EPFRs from the pyrolysis of plastic waste and to deal with multiple waste streams in venous industry park under the implementation of zero waste cities construction. [Display omitted] • Sludge additives contributed to 15.59–48.55% of EPFRs reduction for PET pyrolysis. • Co-pyrolysis reduced the EPFRs through the change of EPFRs types and precursors. • Co-pyrolysis increased the aromatization degree and defects in the carbon matrix. [ABSTRACT FROM AUTHOR]

Integrating biochar into traditional construction materials presents a promising avenue to reduce carbon emissions from the construction industry. While recent research has focused on the performance of biochar-cement materials, limited attention is given to the durability of biochar in cementitious materials. This study investigated the alterations in the structural, chemical, and mechanical properties of biochar in the cementitious system and marine environment. The results showed an increased pore size in the biochar and a potential collapse of its structure after long-term exposure of biochar to an alkaline cement environment. The decline of the aromaticity, 23.8% increase in matrix defectiveness, and formation of organometallic complexes between Ca2+ and oxygen-containing functional groups of biochar indicated that its interactions with hydrated cement would lead to the changes in its chemical properties. The exposure of biochar to the simulated cement solution reduced its Young's modulus from 3.81 GPa to 1.55 GPa and hardness from 0.70 GPa to 0.13 GPa possibly due to the collapse of the pore structure. The saponification reaction might disrupt the cross-linking network structure constructed by COOC and C–O–C in the biochar and release the fulvic-acid organics, causing a decrease in the short- and long-term rebound ratios by 5.6–25.6% and 5–17%, respectively. Biochar exposed to the simulated harsh environment (seawater) exhibited an increase in Young's modulus and hardness by ∼40% compared to virgin biochar. The long-term rebound ratio reached 96.6–99.2% due to brucite, NaCl, and KCl deposition and filling, implying the potential advantage of biochar-cement composites for long-term durability in the marine environment. These findings contribute new insights to the assessment of mechanical performance and durability of biochar-cement composites in diverse environmental conditions. [Display omitted] • Deterioration of biochar when exposed to simulated cement solution was investigated. • Young's modulus and hardness of biochar decreased after exposure to cement solution. • Saponification reaction decreased the rebound rate by disrupting carbon network. • Long-term rebound rate reached 96.6–99.2% when exposed to seawater. [ABSTRACT FROM AUTHOR]

The apple snail (Pomacea canaliculata Lamarck) is among the 100 worst invasive alien species worldwide. Apple snail residues discarded during daily management are potential raw materials for biochar production. This study optimized the factors for producing apple snail biochar (ASB) using response surface methodology (RSM) and analyzed the As removal capacity and soil remediation effects of the optimal ASB. The optimal ASB occurred for 348.63 °C pyrolysis temperature, 2.19 h pyrolysis time, and 2.53 Fe3+/Fe2+ molar ratio. For the optimal ASB, the maximum experimental As(III) removal ratio was 98.72%. Temperature and the Fe3+/Fe2+ molar ratio were essential factors affecting the As removal ratio of ASB. The ASB had a rough surface, and As (1.09%) was evident on its surface after adsorption. The As(III) adsorption capacity on ASB was 10.59 mg/g at 288 K, 9.75 mg/g at 298 K, and 11.82 mg/g at 308 K. The As immobilization efficiency in the 3% and 5% ASB treatments exceeded 50% after 15 d. The 5% ASB treatment increased the soil organic matter, total N, available N, total P, and available P content by 120%, 245%, 47%, 62%, and 154%, respectively. Within 15 d, the soil methane oxidation potential peaked at 4.05 μg/g/h in the 5% ASB treatment. The maximum methane oxidation rate occurred after 10 d in the 5% ASB treatment. ASB has multiple benefits for As immobilization, quality improvement, and methane oxidation in soil. This study provides a reference for optimized production and application of invasive animal biochar in contaminated soil. [Display omitted] • Invasive snail residues can be produced into As adsorbent using RSM. • Apple snail biochar effectively reduces the availability of As in soil. • Snail biochar improves the physicochemical properties of As-contaminated soil. • Methane oxidation potential of As-contaminated soil is enhanced by snail biochar. [ABSTRACT FROM AUTHOR]

The application of biochars in soils has been generating excitement within the scientific community due to its benefits in both agronomic and environmental areas. The current challenge is to select suitable raw materials and preparation procedures to obtain biochars with appropriate properties for specific purposes. Therefore, the objective of this study was to characterize the properties of biochars derived from twenty different types of organic waste and correlate these properties with their potential agronomic and/or environmental use. Twenty types of raw materials available in the Brazilian Amazon were placed in closed porcelain crucibles and subjected to pyrolysis in a muffle furnace set at 350 °C for 2 h. Chemical, physicochemical, and spectroscopic analyses were conducted on the produced biochars. As a result, biochars derived from poultry litter, annatto seed, passion fruit peel, and coffee husk are suitable for improving the fertility of nutrient-deficient soils thanks to their high ash and nutrient contents, elevated pH, and low C/N ratios. Biochars derived from sugarcane bagasse and wood residues were characterized by their high carbon content and aromaticity, making them difficult to mineralize in soil. Consequently, these biochars show promise for environmental use, with the potential to sequester C and mitigate greenhouse gas emissions. [Display omitted] • Biochar properties can identify the research needs and direct future trials. • Biochars produced in the Amazon can improve the fertility of nutrient-deficient soils. • Biochars derived from nutrient-rich biomass can enhance soil fertility. • Biomasses with a high C/N ratio generate biochars capable of sequestering carbon. [ABSTRACT FROM AUTHOR]

Rapid industrialization and urbanization have resulted in the widespread contamination of soil by potentially toxic metal(loid)s (PTMs). Among these, arsenic (As), cadmium (Cd), chromium (Cr) lead (Pb) and nickel (Ni) are particularly concerning, affecting millions of hectares of arable land globally and posing significant threats to food security and human health. Biochar (BC) has emerged as a promising soil amendment due to its ability to mitigate soil pollution by immobilizing contaminants. But how biochar-linked free radicals affect this process in plants and soil remains murky. Additionally, the mechanism of the geochemical transformation of PTMs in soil-plant systems influenced by biochar-based free radicals is unclear. Here, the influence of free radicals on immobilization, and transformation of PTMs in the soil-plant system under various BC and Comp treatment was investigated. Six treatment groups (1% and 2% biochar, compost, combined application, and control) were randomly assigned to pots in a randomized complete block design (RCBD) to test their effects on maize growth. Results revealed that there was a noticeable rise in the concentration of free radicals in both the BC and Comp treatments compared to the control and the combined application of BC and Comp treatments. The biochar treatment showed a slight reduction in these functional groups, suggesting possible adsorption or sequestration onto the BC surface while the Comp treatment led to an increase in functional groups associated with carbohydrates, proteins, and lipids, indicating enhanced organic matter content. The combined treatment exhibited intermediate effects, suggesting a synergistic interaction between Comp and biochar. X-ray diffraction analysis indicated that the BC did not demonstrate significant alterations in soil mineralogy, suggesting minimal direct effects on mineral dissolution or transformation. Conclusively, biochar-generated free radicals, especially hydroxyl radicals (•OH), play a crucial role in PTMs (i.e., Cd, Cr, Ni, As and Pb) immobilization in soil-plant systems. This study provides novel insights into biochar's mechanisms for mitigating PTMs pollution, paving the way for optimized soil amendment strategies. • BC and Comp influence free radicals generation in the soil-plant system. • BC & Comp treatments affect maize growth influence PTMs availability. • BC-based free radicals play a pivotal role in the geochemical transformation of PTMs. • Reveals distinct effects of BC and Comp amendments on soil functional groups. • BC and Comp demonstrate synergistic effects on FR generation and PTM transformation. [ABSTRACT FROM AUTHOR]

Arsenic and cadmium (As/Cd) are toxic elements which negatively impact the health and productivity of rice plants by subjecting them to stress. To address these issues, we developed three biochar amendment materials derived from plant-based corn-stover with iron-magnesium modification (FM@CB), char sourced from animal-based eggshells with iron-magnesium modification (FM@EB), and a blend (1:1, w/w) of both (FM@CEB). Batch adsorption experiment revealed that FM@CB exhibited a Langmuir sorption capacity of 77 mg g−1 for As(III) and 107 mg g−1 for Cd(II). In contrast, FM@EB showed values of 63 mg g−1 for As(III) and 115 mg g−1 for Cd(II), both observed in mixed systems. The exothermic dual adsorption mechanisms could include ion exchange, cation-anion bridging, complexation with surface functional groups, and precipitation processes. Pot trials were conducted, and the findings unveiled a substantial enhancement in rice grain yield with a 2% application of FM@CB, FM@EB, and FM@CEB. Specifically, there was a notable increase of 21.9%, 34.9%, and 37.6%, respectively. Simultaneously, the application led to a reduction in grain As levels by 34.4%, 53.2%, and 42.6%, and grain Cd levels by 48.7%, 71.2%, and 59.9%, respectively, in comparison to the no-amendment control condition. Our study observed a transformation in the soil's microbial community, as beneficial bacterial genera such as Anaeromyxobacter , Citrifermentans , and Desulfovibrio emerged to assist in the detoxification of these metal contaminants. Concurrently, the application of these materials led to a reduction in harmful bacterial genera like Pseudomonas , Flavobacterium , and Massilia. In addition, these amendments decreased the bioavailable As/Cd fractions in the soil and promoted the root-iron-plaque, which effectively sequesters these contaminants, rendering rice quality improvement. Ultimately, the use of these amendments, particularly FM@CEB, holds the promise of protecting rice from harmful metal(loid)s contaminants, increasing yields, and revitalizing the soil. The presence of these unique bacterial genera, especially those capable of detoxifying As/Cd, plays a crucial role in ensuring a healthier and more secure environment for all living organisms. [Display omitted] • Fe–Mg modified plant/animal-based FM@CB, FM@EB, and FM@CEB were prepared. • Biochars' sorption capacity: 63−77 mg g−1 for As(III), 107−115 mg g−1 for Cd(II). • Sorption mechanisms: ion exchange, cation-anion bridge, complexation, precipitation. • Beneficial bacteria aid As/Cd detoxification in treated soil. • 2% amendments significantly reduce bioavailable As/Cd in soil and rice grain. [ABSTRACT FROM AUTHOR]

Agricultural residues in excess of livestock fodder are garnering global attention and stern concerns owing to their accountable share in environmental hazards due to the lack of effective disposal mechanisms and indiscriminate burning. Recycling these residues for biochar production using pyrolysis is a cost-effective and locally feasible technique which offers a twin-prong solution addressing both climate and soil health issues. This research work compares a portable kiln prototype that is affordable and easy to use, with a muffle furnace at three distinct pyrolytic temperatures (400 °C, 500 °C, and 600 °C) to produce biochar from the stalks of maize and pigeonpea. The biochar properties were characterized using Electron Microscopy-Electron Dispersive X-ray (SEM-EDX), X-ray Diffraction (XRD), Fourier Transmission Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis (TGA). The findings indicate significant variations in biochar properties based on raw material source, pyrolytic method, and varied temperatures. Higher pyrolysis temperatures were found to reduce the amorphous organic phase and alter the ultrastructure of biochar, as evidenced by XRD analysis. SEM imaging showed macropores in oval and round shapes with crystalline deposits. The carbon content, as per EDX, decreased with increasing temperature, aligning with changes in functional groups. Edinburgh's stability test revealed that kiln biochar has more stable carbon content compared to biochar produced using muffle furnace and the stable carbon increased with the rise in temperature. A comparative analysis demonstrated that biochar quality at 400–500 °C in a muffle furnace was on par with that produced in the portable kiln at 400 °C. Therefore, considering the kiln's portability, efficiency, cost-effectiveness, and scalability, it is a promising decentralized method for biochar production, offering a cutting-edge solution for agricultural waste management and soil carbon enhancement. [Display omitted] • The study involves redesigning and development of low-cost portable kiln for economical and decentralized biochar production using pigeonpea and maize stalks. • Physiochemical characterization of kiln biochar produced at 400 °C is comparable to muffle furnace biochar produced at 400 °C and 500 °C. • The stable carbon content is more in biochar produced using kiln compared to muffle furnace. • The heavy metal content in the biochar produced is less than critical limits (International biochar initiative). • The low capital and operational cost of kiln proves the technology economical and scalable. [ABSTRACT FROM AUTHOR]

Giant mud crab (Scylla serrata sp.) shell prepared through pyrolysis at various temperatures without any modification were characterized for physicochemical properties and methyl violet (MV) removal potential. Hence, this paper investigated the performance and mechanism of biochar derived from giant mud crab shell as adsorbent in the removal of methyl violet as well as the potential for regenerating adsorbents via hot water regeneration. The results show that CSB500 (produced through pyrolysis at 500 °C) exhibits a surface area of 59.73 m2/g and mesopore size of 31.3 nm, favorable for methyl violet removal at 3139 mg/g. The equilibrium adsorption data agreed well with Langmuir and Redlich-Peterson isotherm models, indicating a monolayer adsorption of MV. The kinetics data fitted better with both pseudo-first-order and pseudo-second-order models. The intraparticle diffusion and Boyd's models revealed that both film and pore diffusion may be involved in the adsorption process. In hot water regeneration studies, CSB500 shown superior regeneration performance when using water with temperature of 70 °C rather than 30 °C for 9th regeneration cycles, with retained to achieve >90 % MV removal for 6th regeneration cycles. Biochar derived from giant mud crab shell has shown significant promise as a low-cost, effective, and ecologically friendly with reasonably good adsorption capacity and reusability for dye removal, and it can be considered as an environmental sustainability strategy in wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

The extensive use of glyphosate-based herbicides and its high solubility in water have led to its accumulation in aquatic environments, posing a risk to the ecological environment and human health. Therefore, an effective method for removing glyphosate from wastewater is urgently needed. Herein, a novel nanosized lanthanum peroxide–loaded biochar composite (n-LBC) was prepared using a simple precipitation method, in which biochar served as a dispersant and catalyst to improve the oxidation ability of nanosized lanthanum peroxide. Compared with other common metal peroxide systems, n-LBC exhibited better oxidation ability and achieved a glyphosate removal efficiency of 99.6%. Moreover, n-LBC retained the self-buffering effect of lanthanum peroxide and thus remained effective over a wide pH range, overcoming the problem of pH elevation observed in other metal peroxide systems. The mechanism for glyphosate removal was found to be a combined process of electrostatic attraction, oxidation, and inner-sphere complex formation. Most glyphosate could be oxidized to H 2 PO 4− by breaking the C–N bonds, and H 2 PO 4 − could be attracted to the material surface simultaneously by electrostatic attraction, forming La–O–P inner-sphere complexes. Thus, n-LBC is a simple and highly effective material for glyphosate removal. [Display omitted] • Nanosized lanthanum peroxide-loaded biochar composites (n-LBC) can thoroughly degrade glyphosate from water. • The n-LBC showed a pH buffering ability to shelter the pH increase problem faced by other metal peroxides. • The biochar acted as a dispersant and catalyst to promote the oxidation ability of the nano-sized lanthanum peroxide. • The.•OH generated by La–O–O– bonds, OFGs, Fe, and La(III) mainly attacked the C–N bonds of glyphosate. [ABSTRACT FROM AUTHOR]

Gaseous emissions (i.e. Greenhouse gases (CH 4 and N 2 O) and NH 3) were a serious environmental problem during composting. Magnesium salt could effectively reduce NH 3 emission with the principle of struvite crystallization. Biochar, particularly modified biochar, could be served as a new type of adsorbent for gaseous reduction. In this study, Mg-modified biochars were successfully prepared with different magnesium to biochar mass ratios, and then used as additives in pig manure composting. Mg-modified biochars exhibited excellent properties in terms of functional groups, porous structure and composition. Adding Mg-modified biochar improved composting performance, and thus synergistically reduced CH 4 , N 2 O and NH 3 emissions. Especially, Mg-modified biochar prepared with the magnesium to biochar mass ratio of 0.50 (MBC-0.50) achieved the best reduction effects during pig manure composting. Both additive and composting phases could influence the bacterial composition by regulating temperature, pH, electrical conductivity and moisture content. Besides biochar adsorption, NH 3 could be further reduced with the formation of struvite crystallization (MgNH 4 PO 4 ·6H 2 O) by adding Mg-modified biochar. Pristine and modified biochars inhibited the proliferation of denitrifying bacteria (e.g. Pseudoxanthomonas and norank-f-Methylococcaceae) and anaerobe methanogenic bacteria (e.g. Jeotgalibaca and Lactobacillus) to further mitigate N 2 O and CH 4 emissions. Results from this study provided unique insights to the development of Mg-modified biochar additive for mitigating CH 4 , N 2 O and NH 3 emissions during composting. [Display omitted] • Mg/biochar ratio impacted Mg-modified biochar (MBC) structure and adsorptivity. • Adding MBC improved composting performance. • MBC-0.50 achieved the best CH 4 , N 2 O and NH 3 reduction effects during composting. • MBC reduced NH 3 emission with biochar adsorption and struvite crystallization. • Biochar and MBCs inhibited the proliferation of denitrifiers and methanogens. [ABSTRACT FROM AUTHOR]

The performance of layered double hydroxides (LDH)-biochar composite on alleviating oil spill pollution is poorly understood. A superhydrophobic biochar (NCY) was synthesized from the pristine wood chips biochar (WCB) after the surface deposition of NiCo-LDH (NCB) and hydrophobic modification with stearate. The oil removal potential of the designed biochars was investigated via the diesel oil/crude oil adsorption experiments and the environmental recalcitrance evaluation. The compared characterization results revealed that NiCo-LDH was successfully deposited onto biochar matrix via the electrostatic attraction and pore filling effect, which facilitated a special flower-like hierarchical architecture rough surface for biochar and hinder the multi-layer stacking of LDH. Benefit from the constructed hierarchical architecture, the occupancy of oxygen-containing functional groups and hydrophobic modification of stearate, the water contact angle of NCY (156°) was remarkably larger than NCB (117°) and WCB (50.1°), which exhibit a superhydrophobic. The maximum diesel oil sorption capacities of biochars increased from 3.28 g/g in WCB to 5.64 g/g in NCB and 11.6 g/g in NCY, as well as the maximum crude oil sorption capacities of biochars showed a similar trend (WCB: 4.64 g/g, NCB: 8.74 g/g, NCY: 18.6 g/g). Accordingly, NCY showed higher oil adsorption capacity than NCB and WCB mainly due to the enhanced hydrophobic forces and the π-π electron donor-acceptor interaction resulted from lower amount of O-containing functional groups and superhydrophobic surface wettability. Furthermore, the application of LDH remarkably improved the environmental recalcitrance of biochar (resist to the chemical oxidation and thermal decomposition in marine) due to the coating of NiCo-LDH could enhance the bulk stability of biochar and increase the liable carbon content in biochar. This study proved that the application of NiCo-LDH and stearate could be an effective approach for improve the oil pollution remediation capacity and the environmental recalcitrance of biochar. [Display omitted] • NiCo layered double hydroxides (LDH) improved the aromaticity of biochar (BC). • -NiCo-LDH constructed a flower-like hierarchical architecture on BC. • -LDH-BC composites modified by stearate (NCY) facilitates a superhydrophobic surface. • -NCY showed higher performance for remediating oil polluted marine than pristine BC. • -Environmental recalcitrance of BC was enhanced by NiCo-LDH. [ABSTRACT FROM AUTHOR]

While traditional biochar demonstrates promising performance in diverse settings, its efficacy may be constrained under specific conditions of high acidity and heavy metal concentrations. In this study, researchers developed a new polysilicon-aluminum alkali mineral-enhanced biochar composite material, GBMSs (green biochar-metakaolin-sodium silicate), by pyrolyzing fibers from dragon fruit peels and blending them with metakaolin and sodium silicate. Using a response surface methodology, this environmentally friendly composite material was optimized for removing copper and zinc contaminants across a range of initial pH levels from 2 to 6. Experimental findings indicated that the adsorption capacity of GBMSs for copper and zinc was significantly enhanced, ranging from 1.5 to 4 times greater compared to pure biochar or biochar mixed solely with a silicon-aluminum mineral. Various analytical techniques including scanning electron microscopy, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy were utilized to examine the influence of poly-silica-aluminum alkali minerals (GBMSs) on biochar composites. The findings revealed an upsurge in surface binding locations and oxygen-related functional groups because of integrating GBMSs. This augmentation of electronegative features on the biochar surface was credited to the development of stabilizing silica-aluminum connections, ultimately boosting its adsorption effectiveness in acidic surroundings. By applying Langmuir and Freundlich models, it was deduced that the adsorption of GBMSs adheres to a multilayer uniform adsorption mechanism, with surface ion interchange and complexation restricting the adsorption capability. This research highlights the potential of clay mineral-altered biochar in efficiently dealing with intricate environmental contamination. [ABSTRACT FROM AUTHOR]

This study investigated the adsorption of pharmaceuticals, including atenolol (AT), 17-α-ethinylestradiol (EE2), and sulfamethoxazole (SMX), in model solutions and in the effluent from a hospital wastewater treatment plant. The pharmaceuticals were adsorbed on biochar prepared from Miscanthus x giganteus biomass obtained from the phytoremediation of contaminated or marginal soil. The feedstock was pyrolyzed at 360 °C (M-3) and 500 °C (M-5). The representation of functional groups, specific surface area, porosity, and pore volume were lower for M-5. Pore diameters were comparable, but their depth decreased for M-5. The specific surface area and porosity surface area of M-5 were 30 times higher after 4 h of shaking compared to properties without shaking. The biochar leachate pH was 9.8 ± 1.0 (M-3), and 11.1 ± 1.1 (M-5). No desorption of potentially risk organic compounds was detected. M-3 was generally a better adsorption material. The removal of EE2, AT and SMX was greater than 90%, 70% and 30 % respectively after 4 h in model waters. There was no evidence of a linear relationship between the sorption efficiency of pharmaceuticals and the biochar dose. Sorption experiments with real wastewater from a hospital wastewater treatment plant demonstrated high removal rates of monitored pharmaceuticals, including e.g. SMX (80%), trimethoprim (91%), venlafaxine (100%), clarithromycin (96%), tramadol (93%), diclofenac (86%). It was proven that the efficiency of the adsorption process is influenced not only by the dose or physico-chemical properties of the biochar, but also by the initial concentration of the pharmaceutical and its properties. The presence of other components of real wastewater, which can cause competitive sorption and overlapping of active centers on the surface of the biochar, also decreased the efficiency. The results demonstrate that both biochars are suitable for tertiary or quaternary water treatment for pharmaceutical removal. Due to the lower energetic, and therefore economic, costs of pyrolysis, a lower pyrolysis temperature can be preferred. [Display omitted] • Utilization of contaminated Miscanthus biomass from soil phytoremediation. • Pyrolysis temperature influenced biochar physicochemical properties. • Char properties changes observed during adsorption process. • Miscanthus biochar is an effective pharmaceutical adsorbent from wastewater. • More than 80% removal efficiency of monitored pharmaceuticals achieved. [ABSTRACT FROM AUTHOR]

Antimony (Sb) contamination in aquatic environments has emerged as a significant environmental concern because of extensive industrial activities involving Sb and its associated health hazards. Nano-zero-valent iron (nFe) is recognised for its efficacy in heavy metal remediation; however, its application is often hindered by poor dispersion and suboptimal adsorption properties. We designed an innovative approach in which nFe is calcined with biochar to mitigate agglomeration and subsequently amalgamated with sodium alginate to form composite gel spheres (PEI/SA/BCFe) in a calcium chloride solution. The ability of these gel spheres to remove antimonite (Sb(III)) from water was evaluated under various conditions, including pH, initial concentration, the presence of competing ions, temperature, and cycling experiments. The R2 fitted to the Langmuir isotherm were 0.99, 0.96 and 0.97, respectively. The adsorption was carried out under thermostatic shaking conditions, and the maximum adsorption capacity was 621.04 mg g−1, 509.34 mg g−1, and 373.10 mg g−1 at 10, 25, and 40 °C, respectively, which corresponded to removal efficiencies of 72.5%, 65.3% and 63.7%, respectively. The underlying mechanisms driving the adsorption process were primarily attributed to the oxidation of Sb(III), inner-sphere complexation, and coprecipitation. This comprehensive study not only highlights the potential of PEI/SA/BCFe as an effective solution for mitigating antinomy contamination in water but also contributes valuable insights into the mechanistic aspects of heavy metal adsorption. • A novel adsorbent (PEI/SA/BCFe) for Sb(III) removal was obtained. • The maximum adsorption of Sb(III) at 25 °C was up to 509.34 mg g−1. • The removal of Sb(III) is related to oxidation-complexation- precipitation. • PEI/SA/BCFe is easily separated and recovered. • PEI/SA/BCFe can be cycled 5 times for Sb(III) adsorption. [ABSTRACT FROM AUTHOR]

Phosphorus recovery from incinerated sewage sludge ash (ISSA) is critical for the sustainable development of phosphorus resources due to its non-renewable nature. An innovative strategy based on a Zr-modified rice-husk biochar (Zr-RB) adsorbent has been proposed for the selective recovery of high-purity AlPO 4 products from ISSA. 0.1 mol/L H 2 SO 4 was chosen to extract phosphorus from ISSA with a phosphorus extraction of 54.5 ± 1.6 mg/g. Phosphorus was selectively adsorbed by the Zr-RB adsorbent with a maximum adsorption capacity of 53.1 ± 0.6 mg/g according to the Langmuir isotherm model. The adsorption kinetics of phosphorus in the leachate followed the pseudo-second order model, suggesting phosphorus adsorption by chemisorption processes. After 5 phosphorus adsorption-desorption cycles, the Zr-RB adsorbent still showed good adsorption performance for phosphorus, indicating its high stability. Electrostatic attraction and ligand exchange on the Zr-RB adsorbent were mainly responsible for the adsorption of phosphorus from the leachate. The simulation and experimental results demonstrated the production of high-purity AlPO 4 products at the pH = 3.0 without the addition of exogenous substances, indicating the application potential of recovering high-value AlPO 4 products from ISSA based on the Zr-RB adsorbent. [Display omitted] • The rice-husk biochar was prepared Zr-RB adsorbent for phosphorus recovery. • The maximum phosphorus adsorption capacity of Zr-RB absorbent reached 53.1 mg/g. • Zr-RB adsorbent could successfully adsorb phosphorus from the complex leachate. • The high-purity AlPO 4 product was recovered from incinerated sewage sludge ash. [ABSTRACT FROM AUTHOR]

Biochar is a product of the thermal treatment of sustainably sourced organics or waste biomass, which enhances nutrient availability and exchangeable cations after soil application. Biochar feedstock is one of the primary factors influencing the availability of exchangeable cations in biochar and soil-biochar mix. However, this influence is not satisfactorily understood due to contrasting data among literature for the cation exchange capacity (CEC) and the lack of standard analysis methods for CEC of biochar and soil-biochar mixtures. Therefore, this research was conducted to assess cation exchange in contrasting soil-biochar mixes, where CEC is measured as (1) the sum of base cations (Na+, K+, Mg 2+, and Ca2+) displaced by ammonium acetate (CEC-BC) and (2) NH 4 + displaced by potassium chloride (CEC-NH 4 +). For the first time, we have evaluated CEC-BC and CEC-NH 4 + in 21 different biochar samples using a modified method. We then used 12 representative biochars with 3 soil types (2% w/w biochar) and provided insights on relative changes in CEC-BC and individual base cations. Some previous studies have indicated a relationship between CEC and surface area and a degree of additivity in the resulting CEC of soil-biochar mixes. However, our study demonstrates an absence of these correlations and a lack of additivity in the representative biochar products. We found that biochar prepared from mixed garden wastes can increase K+ or Ca2+ in loamy or sandy soils and mitigate potential soil sodicity problems in loamy soils. However, a clayey soil may or may not need biochar for the specific purpose of increasing exchangeable cations. Our results revealed that biochar prepared from hardwood or mixed garden waste can retain NH 4 + and deliver it to soil acting as a sink and source for soil nutrients. [Display omitted] • Presence of exchangeable cations in biochar is primarily influenced by feedstock type. • Exchangeable K+ was increased by more than 400% in sandy loam soil after application of 2% w/w biochar. • Hardwood or cellulosic biomass derived biochar increases the cation exchange capacity of clayey soils. • Biochar can help mitigate potential soil sodicity by reducing exchangeable Na+ in loamy soils. • Biochar can store significant NH 4 +, suggesting potential use as a slow-release fertilizer. [ABSTRACT FROM AUTHOR]

Clean water and energy are essential for reducing poverty, fostering economic growth and sustainable development while mitigating CO 2 emissions. Considering that, solar-powered interfacial vapor or steam generation is sustainable and promising environmental technology for both water purification and energy generation while being CO 2 -free. Despite continuous research progress, most of the solar absorbers to capture sunlight following heat conversion for steam generation are generally made from expensive nanostructures, which in part prevents their widespread manufacturing for useful applications. Herein, we experimentally demonstrate a biomass-derived carbon composite membrane that nearly covers the entire sunlight spectrum as a solar absorber with an estimated absorptivity of 90%. As a result, the light absorbed yields a surface temperature of 55 °C at the surface of the B700 and 33 °C for water. Evaporation rates up to 1.26 and 1.16 kg/(m2 h) and solar-to-vapor efficiencies of 80 and 74% were recorded in presence of sodium chloride with two different types of biochar B700 and B300 based photothermal membranes, respectively, under 1 sun illumination. The water evaporation in presence of mixed sodium chloride/magnesium chloride reached up to 1.21 and 1.05 kg/(m2 h) with 77 and 69% efficiency with B700 and B300; due to different solar absorber geometry. Furthermore, by merging the thermoelectric technology, we exploit the concept of hybrid clean water and energy generation. At a relative humidity of 60%, the thermoelectric device may generate approximately 0.9 W/m2 power density. These results highlight the interactive effects of biochar and polyvinylidene fluoride with porous hierarchies and enhanced absorption of sunlight, thus enabling a considerable elevation of temperature with great potential for clean water and energy. Overall biochar photothermal membrane represents a significant advancement as low-cost sustainable technology, addressing both water and energy challenges by providing efficient, environmentally friendly solution for freshwater production and clean power generation. Graphical Abstract for Biomass derived hierarchically porous carbon membrane as solar absorbers for simultaneous steam and energy generation. [Display omitted] • A simple strategy is proposed to fabricate photothermal carbon membrane from wood biomass. • The photothermal membrane has excellent light absorption and covers the entire solar spectrum. • The photothermal membrane has higher solar-thermal efficiency and heat dissipation. • The photothermal membrane has great potential for sustainable desalination and energy generation. [ABSTRACT FROM AUTHOR]

Freeze-thaw cycles (FTCs) are a common phenomenon in seasonal frozen soil areas, which can significantly affect the changes in the soil environment and functional genes of microorganisms. To explore the effect of biochar application on soil carbon and nitrogen cycling under FTCs, an indoor soil column simulation test was used in this study. The experimental setup included different application rates of biochar (0%, 1%, 2%), with the carbon and nitrogen cycle functional genes serving as indicator genes. Real-time fluorescence quantitative PCR technology was employed for analysis. Based on the correlation heat map and redundancy analysis (RDA), the response mechanism of soil environment changes and carbon and nitrogen cycle functional genes before and after FTCs was analyzed. The results revealed that the application of biochar significantly increased soil's water-holding capacity held available nutrients in soil, and increased the ability of environmental change. Due to the influence of soil moisture and aeration, biochar reduced the variation of soil carbon sequestration gene cbbL, cbbM, and nitrogen fixation gene nifH abundance after FTCs. The application of 2 % biochar significantly increased the abundance of the nitrification gene amoA and denitrification gene nirK and enhanced the respiration of soil microorganisms. Soil moisture (SM) is the main environmental factor that determines the abundance changes of the soil carbon sequestration genes cbbL and cbbM. Soil organic matter (SOM), pH, nitrate nitrogen (NO 3 −-N), and ammonium nitrogen (NH 4 +-N) were the main environmental factors determining the abundance of soil nitrogen fixation gene nifH, nitrification gene amoA, and denitrification gene nirK. This study can provide new insights into the internal mechanism of the soil carbon and nitrogen cycle in seasonal frozen soil areas, and provide some reference for the rational application of biochar and the efficient utilization of water and soil resources in seasonal frozen soil areas in the future. [Display omitted] • Applying biochar under freeze-thaw conditions can increase soil nutrient content. • Soil environmental factors are related to microbial functional genes. • Freeze-thaw cycles have a significant effect on carbon fixation genes. • Biochar had little effect on functional genes of nitrogen cycle. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the adsorption and desorption properties of phosphorus on CaCl 2 -modified buckwheat hulls biochar (labelled BBC) and the potential application of BBC saturated with phosphorus as a fertilizer. The findings indicated that phosphorus adsorption was most effective when the buckwheat hulls and CaCl 2 mass ratio was 1:1, the mixture was pyrolyzed at 700 °C (labelled BBC1:1-700), and the BBC1:1-700 dosage was 2.0 g L−1. Thermodynamic analysis revealed that phosphorus adsorption onto BBC1:1-700 was a spontaneous process, with a ΔG0 of −1.12 kJ mol−1. The adsorption isotherm and kinetic models indicated that phosphorus adsorption was a monolayer chemisorption process. XRD, FT-IR and XPS characterization revealed that a Ca–P chemical reaction occurred between BBC1:1-700 and phosphorus to form CaHPO 4. Pot experiments showed that, compared with the soils treated with calcium-containing phosphorus fertilizer (P 2 O 5 ,12%), soils treated with BBC1:1-700 saturated with phosphorus (labelled BBC1:1-700-P) exhibited lower soil bulk weight (from 1.23 to 1.09 g cm−3), increased organic matter content (from 3.62 to 15.83 g kg−1) and phosphorus content (from 0.68 to 1.38 g kg−1), and promoted the growth of buckwheat plants, with root lengths ranging from 1.47 to 4.90 cm and stem lengths ranging from 19.23 to 25.33 cm. These findings indicated that BBC1:1-700 can be used to simultaneously solve the high phosphorus in water bodies and insufficient phosphorus-fertilizer in soils. [Display omitted] • A phosphorus adsorption recovery biochar was synthetized. • The maximum adsorption capacity of phosphorus achieved 75.26 mg g−1. • The biochar after adsorbing phosphorus can be used as phosphorus fertilizer. • The phosphorus fertilizer improved the soil properties and buckwheat growth. [ABSTRACT FROM AUTHOR]

Soil pollution owing to excess molybdenum (Mo) poses a significant threat to the ecosystem and environmental health. However, current knowledge about its effective remediation remains limited. This study comprehensively assessed the phytoremediation of Mo assisted by biochar and microorganisms. The results showed that ryegrass could be used for the phytoremediation of Mo, achieving bioaccumulation factors (BCF) and translocation factors (TF) of 0.69 ± 0.04–0.94 ± 0.01 and 0.83 ± 0.11–1.57 ± 0.05, respectively. Mo was converted into a soluble state (6.56%–58.72%) and a cell wall-bound state (11.48%–48.56%), which were its main fates once it entered ryegrass. The increase in the activities of superoxide dismutase, peroxidase, and catalase alleviated the toxicity of Mo in ryegrass. Biochar and microorganisms, as passivators and conditioners, immobilized the remaining Mo, while facilitating its extraction by plants. Compared with the control, the removal rates of Mo from the soil increased from 7.63% to 24.78% and 25.59% under the treatments of ryegrass/ R.ornithinolytica A1/biochar (T5) and ryegrass/ S.marcescens A2/biochar (T6), respectively. Simultaneously, residual Mo (RES-Mo) proportions increased by 30.12% and 31.24%, respectively. Furthermore, the proportion of RES-Mo increased by 6.22% after the T7 treatment at a lower temperature (10 °C) compared to T8. The redundancy analysis results revealed that all the treatments resulted in increased Mo immobilization and confirmed the more significant positive correlation of RES-Mo with R. ornithinolytica A1 application than S. marcescens A2. The study proposes an effective strategy for the remediation of severely Mo-contaminated soils, particularly in regions with low temperatures. [Display omitted] • Ryegrass cultivation can be implemented for the phytoremediation of Mo. • Mo was primarily converted into soluble and cell wall-bound forms in ryegrass. • The separate and combined use of biochar and microbes promotes the remediation of Mo. • R. ornithinolytica A1 and biochar improved phytoremediation greatly at 10 °C. [ABSTRACT FROM AUTHOR]

The synthesis of efficient and environmentally friendly persulfate (PS) catalysts is currently a prominent research focus. This study employs single-step carbonization to investigate the interactions between endogenous mineral components (EMCs) and N-doping of nitrogen-rich biomass, aiming to design efficient biochar-based catalysts for enhanced tetracycline (TC) degradation. Biochars (PBC and SBC) derived from peanut hulls (PH) and soybean curd residue (SCR) with similar EMCs (ash ratio 16:19) but varying nitrogen content (1 % vs 1.53 %) were achieved, along with melamine-N-doped PBC (PBCN) for comparison under identical conditions. Physicochemical and quantum-chemistry analyses were conducted to investigate the synergistic effects between EMCs and organic-nitrogen in terms of morphological structures, active sites, and catalytic persulfate (PS)-mediated degradation of TC. The findings revealed that the optimal synthesis temperature for the efficient biochar-based catalyst was 800 °C. In contrast to exogenous N-doping with higher N-content (7.81 %), organic-N accelerated lattice disruption, leading to enhanced interactions with EMCs and resulting in the formation of hierarchical structures and pyrrole-N (organic-N 43.44 % > exogenous-N 17.67 %). The SBC/PS system exhibited superior degradation capability, with rapid removal of 95 % in 100 mg·L-1 TC. Density functional theory (DFT) confirmed that the non-radical pathways including 1O 2 and electron transfer, facilitated by the presence of C O and pyrrole-N, were responsible for binding PS and forming biochar-PS*. This study furnishes both experimental data and theoretical insights, supporting the targeted control and efficient advancement of eco-friendly, high-value biochar-based catalysts. [Display omitted] • Efficient biochar-based persulfate catalyst was successfully synthesized via one-step carbonization. • Synergy of endogenous mineral-components template and organic-N doping leads to C O and pyrrole-N's formation. • High-efficiency 1O 2 and electron transfer respond for tetracycline degradation by soybean-curd-residue biochar. • Density functional theory reveals pyrrole-N and C O could jointly promote biochar-PS* and PS's destruction. [ABSTRACT FROM AUTHOR]

Foam concrete boasts widespread applications in backfill engineering, energy-efficient insulation components, and road infrastructure. However, the foam concrete with lower density tends to possess the lower stability. The unstable characteristics of foam concrete restricts its application. In this study, the feasibility of employing biochars to increase stability of foamed concrete is investigated. The rheological properties of base mix are carried out to analyze the foam concrete stability. The analysis of water state, interparticle distance and ion concentration are tested to analyze the stabilization mechanisms. Our findings demonstrate that the introduction of corn husk biochar (CHBC) within the base mix expedites flocculation formation, reducing interparticle distance and subsequently elevating the yield stress. Conversely, the inclusion of rice husk biochar (RHBC) diminishes ion concentration, heightening repulsion forces between particles and thereby reducing yield stress of base mix. Higher yield stress exert the higher constraining force and frictional force to the bubbles, thereby decreasing bubble size in fresh foamed concrete, bettering pore structure, compressive strength and foam stability of foamed concrete. Additionally, the increase in CHBC content enhances pore sphericity, potentially attributed to decreased bubble deformation parameters Ca η. [ABSTRACT FROM AUTHOR]

Dark fermentation (DF) is well regarded and appraised as an efficient and green route for producing hydrogen (H 2). Low yield of hydrogen is an inherent issue of the DF process restricting its further progress towards commercial margins. Biochar, the carbonaceous solid end product of biomass pyrolysis process is a potential additive to amend the DF processes for intensification of hydrogen production. In this article, the biochar amended DF systems have been holistically reviewed and the current state-of-the-art of the integrated technology is presented. Different physical and chemical properties of the biochar namely, surface area and porosity, elemental and compound composition, surface chemical/functional groups, pH, micronutrient content and electroconductivity majorly influence the hydrogen production in DF systems. Amendment of different biochar have remarkably facilitated 20.72–328.51% enhancement of the hydrogen yield (HY) and 26.05–575.41% enhancement of hydrogen production rate (HPR), validating the immense potential of the biochar for amelioration of hydrogenesis performance of DF systems. Formation of stable biofilm of hydrogen producing bacteria (HPB), regulation of the system pH, facilitation of better electron transfer and stimulation of the hydrogenase enzymes are the main factors responsible for enhancement of hydrogenesis by biochar. Doping of biochar by metal/non-metal substance and combining with inorganic nanoparticles also exhibited promising enhancement of HY from DF. Clear understanding of the impacts of biochar on the metabolic pathways of hydrogen production, manifestation of underlying enhancement mechanisms and knowledge of existing barriers is necessary to fully exploit the benefits of the biochar amendment strategy in DF, which are presented in this article. Based on the present state-of-the-art, a closed-loop operation ensuring enhanced resource utilization, carbon circularity and low carbon footprint has been proposed for future development towards large scale clean hydrogen production. [Display omitted] • Biochar amendment improves the hydrogen yield of dark fermentation systems. • Performance of doped and non-doped biochar amended dark fermentation systems were reviewed. • Impact of various physico-chemical properties of biochar on hydrogen production were emphasized. • Integration of biochar in dark fermentation enhances resource utilization efficiency and offers carbon circularity. • Techno-economic and energy-environmental analyses are required to overcome existing challenges. [ABSTRACT FROM AUTHOR]

Various silicon carbide nanostructures are attracting close attention due to their excellent performance and great potential, including utilization in a variety of catalytic applications. Approaches, utilizing different industrial wastes as a starting material for the synthesis of SiC nanoparticles, are especially distinguished due to their environmental friendliness. This paper demonstrates a new two-stage technique of the preparation of dispersed SiC/C nanocomposite. A highly mineralized carbonaceous residue obtained by thermal processing of agricultural waste was used as a precursor for the synthesis in a pulsed arc discharge plasma. Rice husks, oat husks and oat straw were chosen as agricultural wastes with a high content of silicon in the mineral component. Carbonaceous residues (biochars) were obtained from the selected wastes by oxidative carbonization in a reactor with a fluidized bed of a deep oxidation catalyst at 460 °C. High-energy (up to 20 kJ) treatment of the obtained biochars in a pulsed (up to 1 ms) arc discharge plasma jet resulted in synthesizing a nanodispersed material (particle size <50 nm) containing hexagonal silicon carbide α-SiC. The principal possibility of using the synthesized SiC-based composite as a catalyst and cocatalyst of platinum in the hydrogen evolution reaction (HER) of water splitting is shown. The most impressive results (η 10 = 18–28 mV, η 100 = 84–98 mV, b = 32–64 mV) comparable with standard commercial Pt/C samples were obtained by modifying the synthesized SiC-based composite with 5 % platinum. Thus, the developed approach allows us to convert the agricultural waste into useful high-tech products in the form of an electrocatalytically active material. [Display omitted] • A new two-stage approach provides SiC/C nanocomposite from Si-containing biomass. • The proposed approach is almost CO 2 -neutral when utilizing plant agricultural waste. • Pt-modified SiC/C composites has a high activity in HER reaction of water splitting. • Catalytic performance and stability of Pt/SiC/C is almost equal to commercial Pt/C. [ABSTRACT FROM AUTHOR]

Nitrogen-doped biochar has been proven to be an advantageous peroxodisulfate (PDS) activator. However, few studies on PDS activation by biochar prepared from biomass containing intrinsic nitrogen have been reported, and the performance and mechanism are still unclear. In this study, nitrogen self-doped Chlorella biochar (NCB) was prepared by pyrolysis. The results showed that the increase of pyrolysis temperature promoted the formation of graphitic structure in NCB, and the biochar prepared at 900 °C (NCB-900) had the best performance in activating PDS for sulfamethazine (SMZ) degradation. The NCB-900/PDS system had a wide pH applicability and excellent resistance to anion interference, as well as excellent performance in applications such as groundwater remediation. It was suggested that the graphitic nitrogen structures were the main active sites, and the sp2-hybridized graphitic carbon network was favorable for surface electron transfer in the redox reactions on the NCB-900 surface. The degradation mechanism was thoroughly investigated by electron paramagnetic resonance (EPR) test, quenching experiments, chemical probes, electrochemical measurements, and in situ Raman analysis. Rather than free radicals and singlet oxygen (1O 2), surface electron transfer mediated by the NCB-900–PDS* complex dominated SMZ degradation in the NCB-900/PDS system. [Display omitted] • NCB-900 as a persulfate activator was a nitrogen self-doped biochar. • SMZ degradation was dominated by direct electron transfer. • NCB-900–PDS* complex generation was the key to electron transfer. • Graphitic carbon and graphitic nitrogen facilitated the activation of PDS. [ABSTRACT FROM AUTHOR]

To ensure the sustainable cultivation of agronomic crops in agricultural soils polluted with cadmium (Cd), the integrated application of Cd-remediation strategies at edaphic and foliar levels has been examined. However, the integrated application of biochar (BC) and plant growth regulators (PGRs) for mitigating Cd stress, especially in maize, remains unexplored. Additionally, the expression patterns of PGRs and heavy metal transporters during Cd stress are unknown. To address these gaps, a pot experiment (having four replications) was performed to explore the potential effects of the integrated application of BC (B 0 = no BC added; B 1 = low BC at 2.5% w/w; and B 2 = high BC at 5% w/w) and PGRs (H 0 = control; WS = water spray; GA = gibberellin, and IAA = auxin) on maize growth, Cd remediation, and productivity. The study was conducted following a factorial completely randomized design. The pots were artificially spiked with Cd (30 ppm) by using Cd(NO 3) 2 as a source. The synergistic application of IAA/GA and BC, improved the morphological characteristics, photosynthetic activity, stomatal conductance, and catalase activity of maize under Cd stress while simultaneously decreasing electrolyte leakage and oxidant activity. The leaf area, shoot fresh biomass (SFB), and root fresh biomass (RFB), were increased by (13.4, 11.7%), (52.8, 39.3%), and (89.2, 74.3%) in the synergistic application of PGRs (i.e., IAA and GA) + BC (5% w/w) treatments, respectively, than control. Furthermore, a drastic reduction in Cd uptake was observed in maize leaves by (201.53, 179.24%) under the dual application of PGRs + BC (5% w/w) treatments, compared to control, which altered Cd bioconcentration in plant parts and modified Cd species in the soil. Decreased expression of heavy metal transporter PMPCB gene and YCF1 indicated reduced Cd uptake in 5% w/w BC based on RT-PCR quantification. The synergistic application of BC with PGRs can serve as an environmentally friendly remediation to mitigate the hazardous effects of Cd stress on cultivated maize. This was achieved by reducing the bio-concentration and metal transport coefficients of Cd in plants through BC's absorption properties. Overall, applying BC and foliar application of PGRs could be suggested as a sustainable approach for cultivating crops on Cd-contaminated soils while ensuring safety. [ABSTRACT FROM AUTHOR]

CO 2 absorption technology based on amine solutions has sustained appeal due to its high efficiency in post-combustion capture of CO 2. However, the high energy penalty of solvent regeneration limits its large-scale industrial application. Therefore, designing inexpensive catalysts to reduce solvent regeneration energy consumption remains challenging. This study reports a recyclable ternary catalyst, ZrO 2 /SiO 2 /biochar, which was synthesized by co-pyrolysis of zirconium oxychloride and wheat flour in the presence of SiO 2 nanoparticles. The incorporation of biochar improved the distribution of Lewis acidic sites (LAS) and Brønsted acidic sites (BAS). The improved BASs and LASs of ZrO 2 /SiO 2 /biochar catalyst were conductive to donate protons or accept electrons and thus, the amount and rate of CO 2 desorption from CO 2 -saturated monoethanolamine (90 °C) were more than 24% and 26% higher, respectively, to compare with the catalyst-free system at the same conditions. As a result, the energy penalty was decreased by about 31%. A biochar-mediated proton-transfer mechanism that the presence of biochar increased the mesoporous proportion, the BAS and L/B ratio as well as the favorable charge transfer was inferred for the ZrO 2 /SiO 2 /biochar-catalyzed CO 2 release through experimental evidence. The results reveal the role of biochar in solid acid catalysts for CO 2 desorption, which will provide a novel strategy for building solid acid catalysts to reduce energy requirements in CO 2 capture. [Display omitted] • ZrO 2 /SiO 2 /BC was synthesized by co-pyrolysis of ZrOCl 2 and wheat flour in the presence of SiO 2 nanoparticles. • ZrO 2 /SiO 2 /BC catalysis accelerated CO 2 desorption and saved energy. • Biochar increased Brønsted and Lewis acidity of the catalyst. • Biochar promoted charge transfer between ZrO 2 and SiO 2. [ABSTRACT FROM AUTHOR]

This study aims to develop an eco-compatible soil amendment employing maize-stalk-derived biochar in conjunction with plant-beneficial rhizobacteria, Paenibacillus lentimorbus (B-30488) to improve soil properties and chickpea growth under drought conditions. Our results unveiled significant alterations in soil physicochemical properties, enzyme activities, and culturable microbial diversity on the application of B-30488+Biochar treatment. Scanning electron microscopy confirmed the porous structure of biochar, facilitating efficient colonization by B-30488. Under drought conditions, the synergistic application of biochar and B-30488 substantially enhanced chickpea growth as indicated by improved biochemical and physiological status, root architecture, and anatomy. Additionally, phytohormone [Indole acetic acid (IAA), cytokinin (CK), jasmonic acid (JA), and salicylic acid (SA)] and gene expression [ glutathione S-transferase (GST), ascorbate peroxidase (APX), catalase (CAT) and ACC oxidase (ACO)] analyses affirmed their regulatory role in maintaining cellular homeostasis during drought stress. These findings underscore the multifaceted role of the synergistic application of B-30488 and Biochar, offering a sustainable strategy for agriculture and stress resilience. [Display omitted] • Combined use of PGPR and biochar alters soil-physicochemical properties. • Culturable microbial communities were affected by the amendment. • Alteration of phytohormones and stress-responsive genes regulates cellular homeostasis. • Combined use of PGPR and biochar has potential implications in drought mitigation. [ABSTRACT FROM AUTHOR]

Innovative agricultural practices represent the future of the world in the sustainable improvement of agricultural productivity. Sustainable farming practices have been recognized and accepted by agricultural development stakeholders, to provide a wide range of social, economic, financial, and environmental benefits. Despite this recognition, the application of these practices in the literature has focused on socio-economic and technical aspects while the psychosocial elements of the application have received limited attention. To contribute to a broad understanding of the concept, this study aims at analyzing the psychosociological motivations of cotton farmers to use biochar as a sustainable land management strategy. Adopting a survey research design, a sample of 528 farmers in Benin (West Africa) was interviewed on the pillars of the Theory of Planned Behavior (TPB) (Attitude, Subjective norms, Behavioral Control) and three other aspects (Climate change perception, Past behavior and Productivity risk perception) for an extension of TPB. The data collected were analyzed using the structural equation model of the SmartPLS 4 program. The results of this study confirmed all TPB relationships except for the construction of the "Attitude" pillar where Perceived ease of use had no significant influence. Apart from the classical TPB factors, perception of climate change and past behavior in adopting new agricultural practices positively affect the application of biochar. However, possible yield decreases at the beginning of biochar use demotivate farmers to take initiatives in this direction. The study notes that the role of a good perception and knowledge of the effects of climate change and the benefits of biochar action are elements to be considered in promoting sustainable cotton farming and agricultural practices. [ABSTRACT FROM AUTHOR]

Antimony (Sb) and arsenic (As) pollution in the water environment pose a threat to the ecological environment and human health. A lot of studies have been conducted on the removal of pollutants from water by modified biochar, but little attention has been paid to the simultaneous removal of Sb and As from water. This study aimed to simultaneously remediate the water contaminated by Sb and As and realize the resource utilization of solid waste. Herein, electrolytic manganese residue (EMR)-biochar composite (EB) was prepared by a one-step pyrolysis method using the mixture of EMR and distillers grains for the removal of As(III, V) and Sb(III, V) from water. The results indicated that the optimal pyrolysis temperature and EMR to distillers grains mass ratio for EB removal of As(III, V) and Sb(III, V) were 750 °C and 3∶1, respectively. The removal of As(III, V) and Sb(III, V) by EB was inhibited to varying degrees by HCO 3 −, PO 4 3−, and humic acid. The maximum adsorption capacities of EB for As(III), As(V), Sb(III), and Sb(V) were 40.92, 40.54, 34.36, and 9.42 mg/g, respectively. The main adsorption mechanisms of As(III, V) and Sb(III, V) included complexation, hydrogen bonding, and pore filling. Compared with other engineered biochar composites, EB can be utilized not only as a potential adsorbent to treat water contaminated with As(III, V) and Sb(III, V), but also to enable the hazard-free treatment and resource utilization of EMR and distillers grains, achieving the goal of treating pollution with waste. Future studies on the remediation performance and mechanisms of EB for practical Sb and As co-contaminated soil and water are necessary. [Display omitted] • Electrolytic manganese residue-biochar composite was prepared by one-step pyrolysis. • Competitive effect occurs in the adsorption process between As(III, V) and Sb(III, V). • Maximum adsorption capacity for Sb(III, V) and As(III, V) was 9.42–40.92 mg/g. • Pore filling, hydrogen bonding, and complexation dominate Sb and As adsorption. • EDB-3 is a promising adsorbent in Sb and As co-polluted water treatment. [ABSTRACT FROM AUTHOR]

The use of agricultural byproducts as feedstocks for the synthesis of biochar might result in the release of total petroleum hydrocarbons (TPHs) because of the presence of various plastic residues, such as plastic film mulch, gloves, and poles. TPH has been considered a critical health concern for humans worldwide. The aim of the present study was to evaluate the effect of different pyrolysis temperatures and durations on reducing the TPH concentration while synthesizing biochar using agricultural byproducts as feedstock materials. Agricultural byproducts, comprising sawdust and plastic films, were pyrolyzed as feedstocks at temperatures of 400, 500, 600, and 700 °C for durations of 0.5, 1, 2 and 3 h, respectively. Pyrolyzing the feedstock at 500 °C for 1 h and at 600 °C for 0.5 h significantly reduced the TPH concentration in the biochar by 98 and 91 %, respectively, compared to that at 400 °C for 0.5 h. The highest biochar yield was obtained at the lowest pyrolysis temperature (400 °C) and the shortest pyrolysis duration (0.5 h), with a subsequent steady decrease as the temperature and duration increased. These findings underscore the importance of understanding pyrolysis conditions for producing low-cost but high-quality biochar with reduced TPH contaminants and increased biochar yield. This research offers valuable insights for developing sustainable strategies for minimizing the health risks of TPH and utilizing biochar for environmental benefits. [Display omitted] [ABSTRACT FROM AUTHOR]

Biosensors play a very important role in pollutant monitoring, but there are still some problems such as stability, repeatability and low detection limits. Therefore, it is necessary to explore ways to increase the performance of biosensors. In this study, biochar-MFC sensors were constructed for heavy metals monitoring in constructed wetlands (CWs), and the correlation, repeatability and anti-interference were studied. At 1.0 M/L concentrations of heavy metals (Ni, Cu, Zn and Cr), CW with biochar as filler (B-CW) had an output voltage of 0.69 V, extending the detection limit of the sensor. B-CW had advantages in anti-interference and reproducibility. The results showed that B-CW had higher abundance of electrogenic bacteria than CW. Shewanella and Proteobacteria , main electricity-producing bacteria, increased 3-fold. The electrochemically active microorganism Shewanellaceae made up 6.2% of the B-CW microbial population, but was not detected in CW. The abundance of key genes AarC increased by 1295.8% in B-CW. More importantly, the abundance of extracellular electron transport chain related genes (MtrA , OmcA) increased significantly (p < 0.01). Biochar can promote oxidative phosphorylation, thus increasing the sensor's output voltage and detection range. This study is expected to provide support for the engineering application of MFC sensor in CWs. [Display omitted] • MFC-sensors can effectively detect heavy metals in constructed wetlands. • Extracellular electron transfer significantly increased in biochar system. • Biochar increased genes associated with oxidative phosphorylation by about 27%. • Biochar significantly enhanced the repeatability and anti-interference of the sensor. [ABSTRACT FROM AUTHOR]