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This study evaluates the environmental impacts associated with the conversion of garden organic waste into value-added products, namely compost or biochar, employing various processes. Three distinct scenarios are considered: composting garden organic waste followed by screening of oversized materials (CBP), pyrolysis of oversized screenings of compost into biochar AP(I), and in-situ conversion of garden organics into biochar AP(II). A comprehensive Life Cycle Assessment (LCA) was conducted using OpenLCA software and life cycle impact assessment was conducted using Recipe 2016 midpoint methodology. The environmental ramifications of each scenario were assessed, optimising transport distances in AP(II) to achieve a functional unit of one tonne of biochar produced within a cradle-to-gate system boundary. For the first time, this study offers a holistic exploration of the benefits of soil biochar application, extending its scope to climate change mitigation, incorporating the optimisation of transport distance and its influence when scaling up the technology. The results revealed that global warming was increased from 125 kgCO 2 eq during composting of garden waste to 232 kgCO 2 eq where oversized screenings of compost is converted to biochar at an off-site facility. However, direct conversion of the oversized organic waste to biochar, without composting, showed reduced global warming impact of 56 kgCO 2 eq, and is thus the most favourable scenario to limit climate impacts of this fraction of organic garden waste. However, among 18 environmental impact indicators studied, eight indicators were either not influenced or did not significantly increase by transport distance to an off-site pyrolysis facility, while the magnitude of 10 impact indicators increased with transport distance. The insights and methodologies presented in this study hold global relevance, based on an actual case study in regional Australia, offering valuable recommendations for sustainable waste management practices and establishing biochar as a carbon-neutral or carbon-negative solution. The findings contribute to existing waste management knowledge and provide guidance for accessible carbon dioxide removal and soil carbon sequestration technologies. [Display omitted] • A comprehensive LCA for valorisation of garden organics was conducted. • Direct conversion of garden organics to biochar showed least potential environmental impacts. • Biochar provides opportunities for avoided, reduced, and removed carbon from atmosphere. • Maximum transport distance has been identified for individual impact categories. [ABSTRACT FROM AUTHOR]

In this study, seven types of biomass (coffee husk, macadamia husk, peanut husk, rice husk, rice straw, tobacco straw, and cotton straw) were carbonized at temperatures ranging from 300 °C to 1000 °C. This study explored the potential of these biomass samples as carbon reducing agents for industrial silicon and compared them with charcoal in terms of their proximate analysis, electrical resistivity, and apparent activation energy of the reaction. The results indicated that as the pyrolysis temperature increased, the oxygen content and aliphatic functional groups in biochar gradually decreased, as did the volatiles content, while the proportions of fixed carbon and ash increased. The resistivity decreased upon the removal of volatiles and an increase in the degree of graphitization. At 600 °C, the fixed carbon content of all biochar exceeded 65%, and the fixed carbon content of macadamia husk biochar reached 91.32%, which was higher than that of charcoal (81.44%), the maximum specific surface area was 335.706 m2/g, which was much higher than that of charcoal (5.705 m2/g). Thermogravimetric analysis and kinetic analysis indicated that coffee husk had better reactivity than charcoal. The gasification reactivity of coffee husk was R = 3.1949%/min °C, which was higher than that of charcoal (0.7930 %/min °C). The apparent activation energy during the coking reaction stage was 51.86 kJ/mol, which was lower than that of charcoal (98.9 kJ/mol). Overall, biochar had a suitable fixed carbon and electrical resistivity at 600 °C and can be used as a carbon reducing agent for industrial silicon, among them, macadamia husk with high fixed carbon and coffee husk with high reactivity have greater application potential. [Display omitted] • The first proposal to use biomass as a reducing agent for industrial silicon • Coffee husk and macadamia husk have better performance than charcoal. • The mechanism of biomass carbonization was analyzed through kinetic analysis. • The electrical resistivity of biochar decreases with increasing temperature. [ABSTRACT FROM AUTHOR]

Lanthanum (La)-modified biochar has been widely investigated as a phosphate adsorbent material. However, its effectiveness and mechanism as an amendment material to manage sediment internal phosphorus (P) release under anoxic conditions is still unclear. Thus, a lanthanum carbonate-modified shrimp shell biochar (LBC-1) was synthesized for controlling sediment P release, and the efficacy, mechanism, and sediment microbial community impact of LBC-1 under two application modes (addition and capping) were investigated. The maximum adsorption capacity of LBC-1 for phosphate was 79.5 mg/g, superior to most La-modified biochar materials. The generation of LaPO 4 and Ca 5 (PO 4) 3 (OH) precipitates and the formation of inner-sphere complexes were the main adsorption mechanisms of LBC-1 for phosphate. Both the LBC-1 addition and capping treatments successfully blocked sediment P release under anoxic conditions, with the removal efficiencies of DGT-labile P in the overlying water being 97.7–99.7% and 97.5–99.5%, respectively. The conversion of the mobile P forms to the stable HCl-P form in sediments played an important role in the interception of internal P release by the LBC-1 addition treatment. Furthermore, the LBC-1 addition treatment also prevented internal P release by effectively adsorbing DGT-labile P in the interstitial water due to the excellent P adsorption capacity of LBC-1. However, the prevention of P release from sediments by the LBC-1 capping treatment was mainly attributed to the efficient adsorption of DGT-labile P by LBC-1 at the sediment/overlying water interface. The release of P driven by sulfate-reducing bacteria (SRB) was a key mechanism for the migration of P from sediment to interstitial water. The LBC-1 addition treatment reduced the relative abundance of SRB in the surface sediment and might inhibit the release of sediment P into the interstitial water, whereas the LBC-1 capping treatment had little effect on the relative abundance of SRB. In practice, the LBC-1 capping was easier to manipulate than the LBC-1 addition. These findings confirmed that sediment remediation using the LBC-1 capping treatment has great potential to manage internal P loading in eutrophic water bodies. [Display omitted] • LBC-1 addition/capping prevented P release from sediments under anoxic conditions. • LBC-1 addition blocking P release by inactivation of mobile P and adsorption of P. • LBC-1 capping prevented P release due to its high adsorption capacity to P. • LBC-1 addition/capping did not affect the diversity of microbial communities. [ABSTRACT FROM AUTHOR]

Prosopis juliflora (PJ) poses a significant concern to environmental engineers because of its adverse effects on the local communities and environment. The pyrolysis method was employed to recover value-added products from PJ biomass, producing biochar, bio-oil, and pyrogas. A 1:4 biochar-to-KOH ratio produced activated carbon (PJBAC-K4) with a specific surface area of 1140 m2/g and 80% mesopores. The electrode demonstrates a specific capacitance of 288 F/g at 1 A/g. Additionally, the results demonstrate a prolonged lifespan (at least 10,000 charge-discharge cycles), with a retention rate of 91.3% of the initial capacitance. Techno-economic analysis revealed that the net unit production cost of PJBAC-K4 is $18.41 per kg, which comes to around 0.006 cents/F, and the expected payback time is 5.16 years. Sensitivity analysis revealed that process economics is highly vulnerable to utility and raw material prices. The completed life cycle study revealed the environmental benefits of lower global warming potential compared to commercially available activated carbons. [Display omitted] • Prosopis julifora (PJ) was used for producing biochar, bio-oil, and pyrogas. • A 1:4 biochar-to-KOH ratio produced AC with a high specific surface area and mesoporosity. • The produced AC has a specific capacitance of 288F/g and good cyclic stability. • Technoeconomic analysis revealed that activated carbon production cost is around 0.006 cents/F. • Life cycle analysis showed the environmental benefits compared to commercial activated carbons. [ABSTRACT FROM AUTHOR]

Microplastics have attracted extensive public attention due to their harmful effects on environments and organisms, especially for small-size microplastics. Herein, six kinds of biochar were produced by wheat straw and cow dung at 500, 600 and 700 °C respectively for the removal of 1 μm polystyrene microplastics from soils. The removal efficiencies of microplastics exceeded 86% for all biochars. With increasing pyrolysis temperature, the removal performance of wheat straw biochars for microplastics gradually improved, while the removal efficiency of cow dung biochars decreased. Biochars effectively trapped microplastics within their channels, oxygen-containing functional groups (CO 3 2− and COO−) on the surface of biochars facilitated the adsorption of microplastics. After seven cycles of biochars recycling, the removal performance of microplastics remained above 85%, the removal process was primarily governed by the adsorption sites rather than the porous structure of biochars. This article provided eco-friendly and recyclable biochar materials for microplastics removal and technical support for addressing soil microplastics pollution. [Display omitted] • The highest removal efficiency of MPs by cow dung biochar reaches 92.4% at pH 9. • The removal efficiency of MPs remains above 85% after 7 cycles of biochar recycling. • Biochars show great stability and hold promising practical prospects for MPs removal. [ABSTRACT FROM AUTHOR]

This study presents the fabrication of rosette-shaped bismuth oxybromide/biochar (BiOBr/BC) photocatalysts supported on biochar via a straightforward solvothermal approach. This BiOBr/BC photocatalyst demonstrates remarkable efficiency in degrading 17α-ethinylestradiol (EE2). The incorporation of the photosensitizer Rhodamine B (RhB) significantly enhances the degradation rate of EE2, while RhB itself undergoes degradation during visible-light photocatalysis. Biochar serves as a substrate, offering several advantages such as improved adsorption, facilitated electron transfer, and increased production of free radicals, all contributing to the enhanced degradation of EE2 by BiOBr/BC. Under 20 min of visible light irradiation, the degradation rate of EE2 by the RhB-sensitized BiOBr/BC system reaches 99.28%. Furthermore, the incorporation of RhB improves the stability and recyclability of the BiOBr/BC system, maintaining an EE2 degradation rate of 92.00% after seven consecutive degradation cycles. Our photocatalytic system exhibits strong degradation activity towards a mixed-pollutant solution of EE2 and various dyes. LC-MS analysis identified the degradation products and computational predictions indicated their lower ecotoxicity compared to the parent compound. Overall, this study provides new insights and possibilities for the treatment of environmental pollutants, leveraging the concept of "curing waste with waste". [Display omitted] • Synthesized BiOBr/BC with high EE2 photocatalytic degradation activity. • Dual identity of RhB photosensitizer and contaminant. • BiOBr/BC can degrade the coexistence solution of mixed dyes and EE2. • Reduced the overall toxicity of the wastewater containing EE2. [ABSTRACT FROM AUTHOR]

Biochar is a promising amendment for improving soil carbon (C) sequestration and supplying potassium (K). However, the interrelationship between soil organic carbon, potassium availability, and microbial functions under the co-application of biochar and exogenous K remains largely unknown. Therefore, we conducted a four-year experiment that involved four K fertilizer application rates (0%, 60%, 80%, and 100% of conventional K fertilizer, respectively) combined with two doses of biochar rate (0% and 2%). We utilized a combination of high-throughput sequencing and GeoChip technology to examine the microbial responses to changes in soil organic C and K pools. The results revealed that biochar had the potential to replace 40% of conventional K fertilizer. The simultaneous application of biochar and conventional K fertilizer increased soil available K content by 192.3% and enhanced citrus growth. Additionally, soil organic matter, humus components, and aromatic C groups were significantly influenced by the addition of biochar. Soil enzyme activities associated with C cycling improved by 31.9%–84.4%. Furthermore, altered microbial communities, higher bacterial diversity, and enhanced microbial carbon source utilization capacity were observed in soil treated with the combined application of biochar and K fertilizer. The improvement of soil K availability induced by the co-application of biochar and K fertilizer resulted in a 35.2% increase in the microbial functions responsible for liable C degradation. Overall, the 4-years of co-application of biochar and K fertilizer increased the availability of soil potassium and the storage of organic carbon by 2.9- and 1.8-fold, respectively, which is conducive to promoting sustainable agricultural development. [Display omitted] • Biochar shows long-term effect on increasing K fertilizer efficiency. • Biochar improves soil organic C content and microbial C-sources utilization. • Soil exchangeable K content affects microbial functions related to C cycle. • Higher soil K availability promotes the decomposition of liable organic carbon. [ABSTRACT FROM AUTHOR]

Biochar briquettes stand as the current frontrunner for cost-effective and sustainable substitutes for fossil fuels in both energy and industrial sectors. Produced through the thermochemical conversion of biomass to biochar followed by densification, this process yields a renewable briquette that imitate coal in mechanical attributes and combustion efficiency, while maintaining a carbon-neutral profile. Findings indicates that substituting biochar briquettes for coal has the potential to reduce methane (CH 4) and carbon dioxide (CO 2) emissions by approximately 40%. The densification stage plays a crucial role in converting biochar which has low bulk density (0.2 g cm−3 to 0.4 g cm−3), into a coal-like energy product. Thus, effectively addressing concerns associated with handling, transportation, and storage. To ensure the fabrication of high-quality biochar briquettes, particular attention must be directed towards the choice of binder, compaction technology, and operational conditions. In addition, critical briquette quality parameters such as density, mechanical durability, calorific value, and volatile species are influenced by the binder. The optimal binder loading ranges from 5 to 15% depending on the feedstock and pyrolysis temperature. Biochar briquettes produced under these conditions tend to exhibit durability values ranging from approximately 70%–90%. While the existing literature offers broad insights into pyrolysis conditions for various biomass types, available densification technologies, and binder options for biochar briquetting, a more comprehensive understanding of how these factors impact the mechanical and environmental performance is lacking. This review aims to bridge this knowledge gap. By enhancing the biochar densification process to improve energy efficiency, increase mechanical strength, and reduce pollutant emissions, there is real potential for accelerating the transition away from traditional fossil fuel like coal in a variety of industrial applications where it is challenging to decarbonize the production systems. [ABSTRACT FROM AUTHOR]

Olive tree pruning is the most abundant agricultural waste in the Mediterranean region and a sustainable exploitation pathway has yet to be established. In the framework of circular bio-economy, olive tree pruning was converted to biochar which was then characterized by various elemental and surface analysis methods. The olive tree pruning biochar (OTB) and a commercial biochar sample (SON) were combined with cement, each at rates of 2 and 5 % wt. and had their physical and mechanical properties investigated. A small workability loss was determined for both mortars, which was counterbalanced by slightly increasing the superplasticizer dosage to 1.3 and 1.73 % wt. of cement, for the 2 and 5 % wt. OTB, respectively. OTB addition reduced the final setting times both at 2 and 5% addition rates by 51 and 15 min compared to the reference mortar, respectively. The addition of 2 % wt. OTB resulted in 27.8% reduction in porosity and 27.3% reduction in capillary absorption after 28 days, compared to the reference mortar. Furthermore, a 5% wt. addition of OTB resulted in 12.5 and 29.7% increase in compressive strength after 28 and 56 days, respectively. With respect to the flexural strength, 5% wt. SON exhibited a more positive behavior than 5% wt. OTB, achieving a 24.5% improvement compared to 13.3% achieved from the OTB addition, after 56 days. Overall, considering the high atmospheric emissions from the open-burning of olive tree pruning, the conversion to an added-value material such as biochar contributes to carbon sequestration and at the same time improves the long-term mortar durability and behavior. • Olive tree pruning biochar was valorized as cement additive at 2 and 5 % wt. rates. • 2% wt. biochar addition reduced the setting time by 51 min compared to control. • 2% wt. biochar addition reduced the mortar porosity by 27.8% compared to control. • 5% wt. biochar addition resulted in 29.7% increase in compressive strength. • 5% wt. biochar addition resulted in 13.3% increase in flexural strength. [ABSTRACT FROM AUTHOR]

Annually, industries related to agricultural products generate substantial volumes of waste biomass, presenting critical challenges for solid waste management due to its environmental and health implications. Pyrolysis emerges as a significant technique for converting such waste into biochar (BC), a material with notable internal microstructure, porosity, and chemical properties, contingent on the feedstock and processing conditions. BC is recognized for its exceptional water retention and alkalinity, primarily utilized for soil enhancement and fertilization. Its application across various fields, particularly in enhancement for sustainability, has gained momentum. This review meticulously explores BC's role in sustainable composites, focusing on geopolymers and alkali-activated binders through a comprehensive examination of existing literature, underscored by bibliometric analysis. This pioneering review, leveraging the PRISMA framework and VOSviewer for bibliometric insights, aims to bridge the research gap in this evolving domain, offering a critical assessment of BC's integration in sustainable construction materials, its challenges, and future research directions. Hence, this pioneering systematic review represents the first-ever exploration within the research domain of BC's applications in geopolymers and alkali-activated materials, marking a foundational step toward understanding its potential and challenges in sustainable engineering practices. [Display omitted] [ABSTRACT FROM AUTHOR]

Biochar supported sulfidized nanoscale zerovalent iron (S-nZVI-BC) has shown great potential for environmental remediation. However, the feasibility of S-nZVI-BC for the immobilization of cadmium (Cd) in sediment and concomitant ecological consequences remains unclear. Herein, this study systematically investigated the effectiveness, environmental impacts and mechanisms of S-nZVI-BC for remediating of Cd polluted sediment and evaluated the contribution of iron reducing bacteria (IRB) for Cd immobilization. The Cd immobilization by S-nZVI-BC was superior to nZVI, BC, nZVI-BC and S-nZVI, with a maximum residual percentage increasing by 56.93%, the leachability decreasing by 94.48% and the availability reducing by 88.25%. The sediment pH, Eh, dissolved organic carbon (DOC) and leaching Fe2+ played a vital role in Cd immobilization. Three enzyme activities (urease, sucrase, and cellulase) were enhanced after S-nZVI-BC treatment, suggesting an improvement in sediment quality. However, catalase activity decreased, possibly because of the influence of Fe2+ from S-nZVI-BC. The microbial community structure was changed and the abundance of some IRB was improved by S-nZVI-BC. The RT-qPCR results indicated that the absolute abundance of Clostridium (a typical IRB) increased by 1.66 log, which enhanced the iron cycle and Cd re-immobilization. The characterization results confirmed that Cd immobilization by S-nZVI-BC was achieved via adsorption, surface adsorption-complexation and precipitation. Therefore, S-nZVI-BC showed excellent Cd immobilization performance and long-term stability, being well adapted for the treatment of Cd polluted sediment. [Display omitted] • S-nZVI-BC maintained high efficiency for Cd immobilization even after 90 days. • The sediment properties played a vital role in Cd immobilization by S-nZVI-BC. • S-nZVI-BC enhanced the enzymatic activities (urease, sucrase and cellulase). • The iron reducing bacteria (Clostridium) promoted Cd immobilization by S-nZVI-BC. • Adsorption, complexation and precipitation dominated Cd immobilization. [ABSTRACT FROM AUTHOR]

Every year, billions of tons of iron-rich waste are generated globally, presenting a valuable resource for synthesizing iron-based catalysts. In this study, we synthesized iron oxide-biochar (Iron Oxide@Biochar) nanocomposites by ball milling a combination of tea leaves and iron-rich waste. These nanocomposites were found to be highly efficient activators of peroxymonosulfate (PMS) for degrading tetracycline (TC). Particularly, biochar-encapsulated disposable instant hot packs (DHP/BC) achieved a TC removal efficiency of 94.7% under optimal conditions, exhibiting excellent stability and strong anti-interference capabilities. Our analysis revealed that TC degradation predominantly occurred via a non-radical pathway involving singlet oxygen (1O 2) and electron transfer, with free radicals (·OH and SO 4 ·-) playing a secondary role. This research not only offers an economical and efficient solution for recycling solid waste and reusing natural biochar but also introduces a sustainable and environmentally friendly method for preparing catalysts for pollutant degradation, thus achieving the dual goals of "resource recycling" and "treating waste with waste." [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, a green and economically efficient adsorbent was prepared from discarded longan seed. Hydrochloric acid-modified longan seed biochar (HNSB), as the final product, possesses excellent adsorption properties. BET characterization of HNSB demonstrates impressive porous properties with a specific surface area of 420.58 m2/g. Batch adsorption experiments were conducted with gatifloxacin (GAT), norfloxacin (NOR), and lomefloxacin (LOM) as representatives of typical fluoroquinolone antibiotics (FQs). The adsorption capacity of HNSB for FQs exceeded 40% of that of commercial activated carbon. The sustained effective time of HNSB dynamic adsorption for treating high concentrations of FQs wastewater was more than 20 h. Adsorption kinetics and isotherms were fitted by the pseudo-second-order model and the Langmuir model. The adsorption mechanism includes the pore-filling effect, electrostatic attraction, reduction reaction, hydrogen bonding, π-π interaction, and hydrophobicity. This study provides an economic and feasible strategy for the engineering application of agricultural wastes in pharmaceutical wastewater treatment. [Display omitted] • Hydrochloric acid-modified longan seed biochar (HNSB) was produced as a green and economically adsorbent. • HNSB has a high specific surface area of 420.58 m2/g. • HNSB can effectively treat high concentrations of FQs wastewater for more than 20 h. • The adsorption capacity of HNSB for FQs exceeded 40% of that of commercial activated carbon. • Adsorption mechanism by a combination of pore filling, π-π interaction, reduction, hydrogen bonding and hydrophobic effects. [ABSTRACT FROM AUTHOR]

Pyrogenic carbon capture and storage (PyCCS) based on biochar is considered a negative emission technology (NET) aimed at mitigating climate change, with the potential to reduce CO 2 by 0.3–2 gigaton/yr at the cost of $30–120/ton-CO 2. The annual biochar production needs a substantial scaling up of the current production rates (i.e., >150 million tons by 2050) to meet the above demand. However, current biochar production predominantly relies on a small-scale operation, which generally leads to high operational costs and limited control of the biochar properties. This work presents the operation of a state-of-the-art 1 ton/d pilot-scale Flexible Counter Flow Multi-Baffle (F-COMB) pyrolyzer designed for continuous biochar production, which is a prototype reactor for the scale-up. The F-COMB utilizes counter-flow and vortex mixing in a multi-baffle column structure to enable efficient contact of feedstock with hot gas. It boasts high energy efficiency and economic feasibility through a short residence time, reduced gas flow rate, and simple structure. It produces wood pellet biochar with accurate control of the reaction conditions such as temperature, retention time, hot gas flow rate, and feedstock loading. Moreover, continuous biochar production is done successfully with three flexible baffles configuration, demonstrating the significant potential for the scale-up. • Flexible Counter Flow Multi-Baffle (F-COMB) reactor is designed for pyrolysis. • F-COMB provides high energy efficiency via efficient contact of feedstock & hot gas. • Vortex mixing induced by multiple baffles gives the efficient contact. • Biochar production using a F-COMB was demonstrated at 1 ton/day scale successfully. • Continuous biochar production shows significant potential for the F-COMB scale-up. [ABSTRACT FROM AUTHOR]

The current study aims to develop an intelligent system incorporating various mitigation technologies. In this investigation, three technologies; Direct Air Capture (DAC), Bioenergy with Carbon Capture and Storage (BECCS), and Biochar production from pyrolysis are evaluated for their capacity to mitigate one million tonnes of CO 2. Process models are developed for each method, followed by techno-economic analyses and optimization to derive the most effective solution. The holistic approach considers objectives such as net energy gain, minimized water usage, and product sales. The results highlight BECCS as the most promising in terms of net energy gain, offering approximately 18.08 GJ, closely followed by Biochar, which offers about 15.08 GJ per 1 tonne of captured CO 2. Biochar stands out for its lower water consumption of 2.3 m³ compared to BECCS water consumption of 3.03 m³, while DAC exhibits higher water usage and demands extensive energy consumption of 11.95 GJ per 1 tonne of captured CO 2. Economic analysis reflects these scenarios, with Biochar, BECCS, and DAC presenting product sales of $756 million, $233 million, and $60 million, respectively. The optimization process revealed about 22 potential solutions based on energy, waste usage, and sales nexus. It suggests a system comprising 53% Biochar and 47% BECCS, considering the highest net energy gain, minimizedwater usage and cost and elevated technology maturity. [Display omitted] • Three key technologies; DAC, BECCS, and biochar are evaluated for net emissions. • DAC appears to involve a more extensive use of water and energy. • BECCS produced a higher net energy gain compared to other processes. • In economic parameters, biochar and BECCS have higher product selling values. • The optimal hybrid system (BECCS 47% and biochar 53%) for mitigating 1 Mt of CO 2. [ABSTRACT FROM AUTHOR]

Designing efficient catalyst for peroxymonosulfate (PMS) activation is beneficial for eliminating the adverse effects of sulfamethoxazole (SMX) on human health. A novel boron (B) and nitrogen (N) co-doped sludge biochar (BNSBC) was synthesized by one-pot hydrothermal activation, and its remarkable PMS activation performance facilitated the rapid elimination of SMX from water. The degradation rate of SMX by BNSBC/PMS system could reach 92.1% within 60 min ([SMX] 0 = 10 mg/L, [BNSBC] 0 = 0.4 g/L, [PMS] 0 = 1 mM). B and N exhibited the synergistic enhancement effects on the physico-chemical characteristics of SBC, and abundant pores, defects, C O, -O-B-O-, graphitic-N and pyridinic N were confirmed as the main active sites of BNSBC for PMS activation. Characterization, quenching, electron paramagnetic resonance (EPR) and electrochemical tests proved that non-radicals of surface-bound, 1O 2 and electron transfer were the main contributors to SMX degradation. The high anti-interference of BNSBC/PMS system to pH range, co-existing inorganic anions and organic matter guaranteed its outstanding purification performance for SMX in diverse environmental waters. Four potential degradation pathways of SMX in BNSBC/PMS system were proposed by its intermediates identification and density functional theory (DFT) calculation, and pathway Ⅳ was the main one. The toxicity levels of its intermediates were lower than that of SMX regardless of chronic and acute toxicity. Also, BNSBC/PMS system exhibited the board-spectrum removal performance for other typical antibiotics (e.g., sulfadiazine (SDZ), sulfamethoxypyridazine (SMP), ciprofloxacin (CIP), tetracycline (TC)). BNSBC/PMS has great application potential for eliminating diverse antibiotics in actual wastewater due to its high tolerance to complex environmental conditions and outstanding detoxification ability, also it offers a harmless disposal approach for sludge. [Display omitted] [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]

Sewage treatment plants (STPs) are identified as a significant pathway of microplastics (MPs) re-entry into the environment through effluent discharge, thereby emphasizing the need for reliable and efficient treatment methods. This study investigated MPs removal from sewage effluents using cetyl trimethyl ammonium bromide (CTAB)-modified magnetic biochar (RH-MBC-CTAB) as an adsorbent. Biochars from different biomass were synthesized, surface modified, characterized, and compared for their MPs removal efficacy from aqueous matrices. Batch adsorption studies were initially conducted on synthetic water with 1 μm sized polystyrene (PS) MPs using different MP concentrations (1–10 mg/L) and varying adsorbent dosages (1–10 mg/50 mL) to assess the effect of different process parameters, viz. pH (2–10), humic acid (6–25 mg/L), and competitive ions (0.01–0.2 M). The maximum MPs removal (98%) was achieved at the favorable conditions: initial MPs concentration: 10 mg/L, RH-MBC-CTAB dose: 7 mg/50 mL, pH 4, mixing speed: 180 rpm, and contact time: 3 min. Electrostatic attraction and hydrogen bonding were likely to remove MPs while the MPs adsorption was best fitted by the pseudo-second-order kinetics model (R 2 = 0.91) and Langmuir isotherm model (R 2 = 0.94) with the maximum adsorption capacity of 247.52 mg/g. Further, the application of RH-MBC-CTAB on the real-time sewage effluents from sequencing batch reactor (SBR) and moving bed biofilm reactor (MBBR)-based STPs spiked with MPs showed up to 96% MPs removal. The reusability results revealed that developed RH-MBC-CTAB could maintain good stability for up to three reusability cycles, therefore offering extensive potential for the removal of MPs from sewage effluents. [Display omitted] • Biochar prepared and modified by FeCl 3 and cetyl trimethyl ammonium bromide (CTAB). • CTAB-modified magnetic biochar used for adsorptive MPs removal from aqueous matrices. • The maximum MPs removal achieved using CTAB-modified magnetic biochar was ∼98%. • The Langmuir and pseudo-second-order models better described MPs adsorption process. • MPs removal from STP effluent by the adsorbent: 96.3% (SBR-based), 94.1% (MBBR-based). [ABSTRACT FROM AUTHOR]

Agriculture is among the major contributors to soil and groundwater pollution, primarily through the widespread leaching of pesticides and fertilizers from crops, as well as accidental releases from point sources. Therefore, alongside restrictions on the use of highly soluble agrochemicals and enhanced application guidelines, there is a significant demand for low-impact and cost-effective solutions aimed at reducing the mobility of agrochemicals in the soils. This study evaluates the potential of soil amendments—commonly used to enhance soil structural properties, water holding capacity, and fertility—to also absorb highly soluble pesticides, thereby controlling their leaching into the subsoil. Specifically, zeolite, biochar, and milled corncob were examined in laboratory tests under static (batch tests) and dynamic (column leaching tests) conditions to assess their effectiveness in adsorbing two widely used pesticides, copper sulphate and dicamba. Batch adsorption tests were performed using the amendments as pure materials and in mixtures with sand at various application rates (1–20% by weight). The highest affinity to copper sulphate was recorded for biochar, while dicamba exhibited a higher affinity to corncob, thanks to its higher content of organic carbon. Column leaching tests, performed at an amendment application rate of 5%, confirmed the different affinity observed in batch tests among pesticides and amended soil. Less than 2% of copper sulphate leached out from biochar- and zeolite-sand columns, while a recovery of 10% and 56% was observed for the corncob-sand mixture and for pure sand, respectively. Dicamba leaching from biochar- and corncob-sand columns was halved compared to pure sand. In conclusion, the tested soil amendments resulted highly effective in reducing pesticide leaching, opening the way for their possible applications in agriculture to reduce or prevent both diffuse and punctual contamination. [Display omitted] • Biochar and corncob show high affinity to dicamba and limit its leaching in lab tests. • Zeolite-amended sand highly retain Cu sulphate and retention is partly irreversible. • Unprocessed agricultural waste can effectively control leaching of organic pesticides. [ABSTRACT FROM AUTHOR]

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]