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There is an urgent need to develop effective and sustainable methods to decrease sulfonamide (SA) contamination of soil. Herein, a non-homogeneous system of zero-valent metal-biochar-based composites was proposed and tested for persulfate (PS) activation. This system employed zero-valent iron (Fe 0 ) as an electron donor to catalyze the cleavage of the OO bond in PS, thereby generating reactive oxygen species (ROS) that degrade SAs. Notably, the incorporation of elemental sulfur (S) significantly mitigated the passivation of Fe 0 , leading to an enhanced degradation capability of the system. The system decomposes 84-97 % of SAs at their concentration in soil suspension 10 mg/kg in 3 h. Among the coexistence of several SAs, the system showed the fastest degradation rate of sulfisoxazole with a k obs of 0.0305 min -1 , nearing complete removal within 3 h. The system is resistant to the impact of organic matter in soil. It allows to decrease concentration of sulfadiazine in actual contaminated soil on 73 % in 2 h. The system remains effective with decreasing concentrations of PS from 20 mM to 2.5 mM, which lowered the operating cost. T.E.S.T software evaluation showed a significant reduction in the bioaccumulation toxicity and developmental toxicity of the degradation products, suggesting that the system is environmentally friendly. The high efficiency of the catalytic system, the simplicity and economy of the manufacturing process, the resistance to interference in real soil, and the environmental friendliness make this technology promising for mitigating the problem of the environment contamination by SAs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier B.V. All rights reserved.)

The role of biochar in reducing greenhouse gas (GHG) emissions and improving soil health is a topic of extensive research, yet its effects remain debated. Conflicting evidence exists regarding biochar's impact on soil microbial-mediated emissions with respect to different GHGs. This study systematically examines these divergent perspectives, aiming to investigate biochar's influence on GHG emissions and soil health in agricultural soils. The meta-analysis includes 2594 paired observations from 157 studies conducted between 2000 and 2024. It was found that biochar increased the presence of amoA and nosZ genes by 39.4 % and 41.7 %, respectively, while reducing the abundance of the nirS gene by 17.8 %. This led to a 13.1 % decrease in N 2 O emissions. Nitrous emissions were positively associated with mean annual temperature and biochar's pyrolysis temperature and dosage while inversely related to soil pH, nitrogen fertilisation rate, and biochar pH and carbon content. Biochar also regulated enzyme activity related to the nutrient cycle and increased microbial biomass carbon, nitrogen, and phosphorus by 16.6 %, 23.9 %, and 50.2 %, respectively, leading to changes in microbial community diversity. These changes contributed to a reduction in CO 2 and CH 4 emissions, particularly when biochar and nitrogen fertiliser were applied at doses below 21.4 t ha -1 and 242.5 kg ha -1 , as predicted by machine learning models. This study offers an overview of the positive impact of biochar amendments on soil GHG emissions mitigation. The key predictive factors identified could help optimise biochar production and targeted amendments, potentially improving soil health and achieving carbon neutrality in agroecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 The Authors. Published by Elsevier B.V. All rights reserved.)

The conversion of organic matter to methane through anaerobic digestion (AD) process can be enhanced by different materials. However, literature reports show inconsistent results on the effect of materials in different AD systems. In this study, we evaluated the influence of the inoculum's activity on methane production (MP) efficiency in the presence of different materials (activated carbon (AC), magnetite (Mag), and zeolite (Zeo)). The inocula included pure cultures of methanogens, syntrophic cocultures, and complex microbial communities, and the kinetic parameters assessed were the lag phase duration and methane production rates (MPR). The results showed that the microbial activity of the inocula is an important factor determining materials' effect on MP kinetics. AC, Mag, and Zeo significantly enhanced the MP profiles of less active microbial communities or low-active microorganisms by decreasing lag phases duration up to 85 %, consequently increasing MPR up to 15 times. Contrarily, these materials did not affect highly active microbial communities or pure cultures, as MP profiles tend to be similar with and without materials. These results indicate that from an applied point of view, the addition of materials to anaerobic bioreactors should be considered only when the methanogenic activity of the sludge is low or compromised., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Antimony (Sb) toxicity is a serious concern due to its harmful effects on humans and plants. Biochar (BC) has become a popular amendment for remediating soils polluted with metals and metalloids. However, the exact interaction mechanism between BC, and microbes to remediate Sb-polluted soils remains unclear. To address this, a study was performed to determine the impacts of maize straw BC and a bacterial strain (Pseudomonas frederiksbergensis: PF) in mitigating the harmful effects of Sb toxicity on sorghum productivity. A pot experiment was set up with the following treatments: control, soil contaminated with Sb (1000 mg kg -1 ), Sb-contaminated soil + BC (2 %), Sb-contaminated soil + PF, and Sb-contaminated soil + BC (2 %) + PF. Antimony toxicity significantly reduced sorghum biomass and grain yield while increasing hydrogen peroxide (H 2 O 2 : 32.63 %), malondialdehyde (MDA: 68.96 %) reducing chlorophyll a (95.65 %) and chlorophyll b synthesis (92 %), increasing Sb accumulation in plant parts and decreasing soil NPK (24.48 %, 8.01 % and 19.24 %) availability, soil organic carbon (SOC: 16.36 %), microbial biomass carbon (MBC: 10.80 %) and soil urease (76.31 %) and catalase (130.52 %) activity. The combined application of BC and bacteria enhanced the sorghum biomass and grain production by improving chlorophyll synthesis, antioxidant activity, osmolyte production, nutrient availability, SOC, MBC, soil enzymatic activities and reducing both H 2 O 2 and MDA production. Co-application of BC and bacteria decreased soil Sb concentration by 38.84 % while they decreased Sb concentration in sorghum root, stem, leaves and grains by 54.58 %, 34.15 %, 30.96 % and 54.58 % respectively. The decrease of Sb concentration in soil and plant parts with BC and bacteria application was attributed to increase in soil pH, SOC, MBC, enzymes activities. Additionally, BC in combination with bacteria also reduced bio-accessible Sb concentration by 83.82 %, and bio-accessibility of Sb by 36.45 % indicating their appreciable potential to produce safer sorghum production in highly polluted Sb soils. Therefore, BC and PF can be used together to improve sorghum production and develop environmentally friendly approaches in Sb-contaminated soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The environmental hazards of nanobiochar (n-BC) require attention due to limited knowledge. This study is the first to explore the effects of biochar size reduction across various organisms, including bacteria (Allivibrio fischeri), plants (Lemna minor, Lepidium sativum), and invertebrates (Daphnia magna, Folsomia candida). Bulk biochar (b-BC) and n-BC were applied in both liquid and solid-phase tests to assess their ecotoxicity. The resulting leachates were tested at concentrations of 2, 10, and 100 mg/L on organisms such as Daphnia magna and Lemna minor. In the solid-phase tests, b-BC and n-BC were added to the OECD soil at concentrations of 1 % and 5 % to evaluate toxicity in Folsomia candida and at concentrations of 1 % to evaluate toxicity in Lepidium sativum. We found n-BC to be significantly more toxic (by 18 % to 2886 %) to A. fischeri than b-BC, with toxicity increasing over time. Low doses (1 %) of both b-BC and n-BC did not cause mortality or inhibit reproduction in F. candida, though b-BC enhanced reproduction (by 30 % to 56 %) compared to n-BC. At a 5 % dose, both b-BC and n-BC inhibited reproduction F. candida, with n-BC being 0.5 to 1.8 times more toxic. Neither b-BC nor n-BC immobilized D. magna, but both inhibited reproduction (by 28 % to 35 %). The nanoscale dimensions of n-BC facilitated bioaccumulation in D. magna, leading to adhesion on the organism's body. The n-BC had a greater impact on plants, both b-BC and n-BC were non-toxic to L. minor, but all n-BC inhibited root growth in L. sativum. These findings highlight the importance of considering biochar size, feedstock, and pyrolysis conditions when evaluating environmental risks, ensuring safe use in sustainable agriculture., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The effects of engineered steam exploded biochar on the phytoavailability of toxic elements in the shared- and nonshared-rhizosphere of vegetable-grass intercropping system have not been investigated yet. Therefore, we explored and elucidated the synergistic effect of pristine rape-straw biochar (BC), steam exploded BC (BCSE), KMnO 4 -modified BCSE (BCSEMn), and hydroxyapatite-modified BCSE (BCSEHA) on the solubility, fractionation and phytoavailability of lead (Pb) in a vegetable-grass intercropping system. In a rhizosphere box, Brassica chinensis L. (pakchoi; PC, as a vegetable) and Pennisetum polystachion L. (mission grass; MG, as a Pb hyperaccumulator), were grown in the biochar treated soil with (non-shared rhizosphere) or without (shared rhizosphere) root separation. Addition of BCSEMn and BCSEHA, particularly BCSEMn, significantly improved plant growth, photosynthetic pigment levels, and positively influenced the gas exchange attributes by suppressing oxidative stress and boosting antioxidant enzymes activities. Both biochars altered a proportion of Pb in the acid soluble to the immobile fraction and thus significantly decreased its leachability (TCLP-Pb) and bioavailability (CaCl 2 -extrcated Pb) by 32.7 %-33.9 % and 48.5 %-53.5 %, respectively, as compared to the control. Both biochars, particularly BCSEMn, reduced significantly the Pb content in shoots and roots of PC and MG with a significantly higher efficiency in the PC than in the MG; this was the case more in the shared than in the non-shared rhizosphere. These findings indicate the synergistic effect of BCSEMn and BCSEHA and intercropping for enhancing the grass phytostabilization capacity for Pb and reducing its uptake by edible plants in a vegetables-grass system, which could be used as a promising approach for the phytomanagement of Pb contaminated soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Purpose: To explore the mechanisms of tolerance of Brassica napus to ultra-high concentration cadmium pollution and the synergistic effects of biochar (BC) and Arbuscular mycorrhizal fungi (AMF) on plant growth under cadmium (Cd) stress., Results: The application of 5 % BC and inoculation with 10 g AMF significantly promoted the growth and development of B. napus. The combined application of BC and AMF (BC1A and BC2A) was better than the single application. At the Cd 200 mg/kg level, BC1A increased the fresh weight and Cd content of the above-ground parts of B. napus by 35.5 % and decreased by 21.20 %. The SOD and POD activities increased by 30.63 % and 73.37 %. The MDA and H 2 O 2 contents decreased by 40.8 % and 69.99 %, soluble sugar content increased by 37.96 %. At the Cd 300 mg/kg level, BC1A increased the fresh weight and Cd content of the above-ground parts of B. napus by 32.8 % and decreased by 15.99 %. The SOD and POD activities increased by 39.06 % and 93.56 %. The MDA and H 2 O 2 contents decreased by 28.39 % and 72.45 %, and the soluble sugar content increased by 21.16 %. Overall, both BC and AMF treatments alone or in combination (BC1A) were able to alleviate Cd stress and promote plant growth, with the combination of biochar and AMF being the most effective. Furthermore, transcriptome analyses indicated that BC may improve cadmium resistance in B. napus by significantly up-regulating the expression of genes related to peroxidase, photosynthesis, and plant MAPK signaling pathways. AMF may alleviate the toxicity of Cd stress on B. napus by up-regulating the expression of genes related to peroxisomes, phytohormone signaling, and carotenoid biosynthesis. The results of the study will provide support for ecological restoration technology in extremely heavy metal-polluted environments and provide some reference for the application and popularization of BC and AMF conjugation technology., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dan Qiu reports financial support was provided by Chongqing University. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Nitrogen (N) fertilizer is often used in production practice to effectively maintain crop productivity; however, low nitrogen use efficiency (Nue) has always been a problem. Specifically, the transformation and utilization of nitrogen fertilizer by biochar and the driving mechanisms remain unclear. We used four biochar application rates (0, 3750, 7500, and 11,250 kg·ha -1 ) and analyzed the effects of biochar on nitrogen fertilizer utilization, residue, and loss over three years using 15 N isotope tracer technology. The results showed that (1) biochar improved the nitrogen use efficiency of maize plants, reduced total nitrogen loss, and increased the maize yield. Compared to the control treatment in the same year, the application of 7500 kg·ha -1 biochar increased the nitrogen use efficiency by 24.27 %, 27.77 %, and 35.82 %, and the yield increased by 21.1 %, 26.7 %, and 24.5 %, respectively. (2) Biochar increased the proportion of mineral nitrogen supplied by fertilizer in the mineral nitrogen pool. The application of 7500 kg·ha -1 biochar increased mineral nitrogen by 3.05 %, 3.22 %, and 3.8 %, respectively, compared to the control treatments in the same year. Biochar promoted the transformation of nitrogen in the 0-40 cm soil layer to three different soil nitrogen pools, especially the organic nitrogen pool. (3) Biochar significantly improved the soil bacterial community and increased the abundances of N transformation functional genes. The redundancy analysis (RDA) showed that the gdhA mineralization gene was the driving factor of nitrogen fertilizer transformation, contributing 43.6 % of the variance. In summary, the application of 7500 kg·ha -1 of biochar for two consecutive years was conducive to maintaining farmland soil fertility, while its use would not be recommended for more than three consecutive years., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Biochar application to amend acidified tobacco-soils can enhance tobacco quality and reduce nitrous oxide (N 2 O) emissions. Microplastics from agricultural mulch are commonly found in cash-crop farmland soils and, together with biochar, affect soil N 2 O emissions. In this study, we applied three types of microplastics (polyethylene, PE; polylactic acid, PLA; polybutylene adipate terephthalate, PBAT) and rice biochar alone or in combination to acidified tobacco planting soil in central China to investigate their effects on soil N 2 O emissions, soil chemical properties, nitrogen-cycle-related functional genes, and microbial functional diversity during a 35-day laboratory incubation period. Significant increases in N₂O emissions were observed with PE and PLA, which raised emissions by 15.96 % and 21.52 %, respectively. Additionally, different microplastics affected soil N₂O emissions through distinct regulatory pathways. Co-application of microplastics and biochar suppressed N 2 O emissions compared to microplastics alone. Biochar mitigates N 2 O emissions mainly by increasing the abundance of the nosZ gene. It can remediate soil contaminated by microplastics and reduce their negative impacts on the soil environment. This study provides deeper insight into the effects of microplastics on soil nitrogen cycling and biochar-mitigated remediation of microplastic-contaminated soil., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Nitrogen (N) and carbon (C) inputs substantially affect soil microbial functions. However, the influences of long-term N and C additions on soil microbial resource limitation and heterotrophic respiration-fundamental microbial functional traits-remain unclear, impeding the understanding of how soil C dynamics respond to global change. In this study, the responses of soil microbial resource limitation and heterotrophic respiration (Rh) to 7-year N and biochar (BC) additions in a subtropical Moso bamboo (Phyllostachys edulis) plantation were investigated. We used eight treatments: Control, no N and BC addition; N30, 30 kg N (ammonium nitrate)·hm -2 ·a -1 ; N60, 60 kg N·hm -2 ·a -1 ; N90, 90 kg N·hm -2 ·a -1 ; BC20, 20 t BC (originating from Moso bamboo chips) hm -2 ; N30 + BC20, 30 kg N·hm -2 ·a -1  + 20 t BC hm -2 ; N60 + BC20, 60 kg N·hm -2 ·a -1  + 20 t BC hm -2 ; and N90 + BC20, 90 kg N·hm -2 ·a -1  + 20 t BC hm -2 . Soil microbes were co-limited by N and phosphorus (P) and not limited by C in the control treatments. Long-term N addition enhanced soil microbial N and P limitation but significantly reduced soil Rh by 15.1 %-20.0 % relative to that in the control treatments. BC amendment alleviated soil microbial N and P limitation and significantly decreased C use efficiency by 10.9 %-42.1 % but increased Rh by 33.6 %-91.6 % in the long-term N-free and N-supplemented treatments (P < 0.05). Soil C- and N-acquisition enzyme activities were the dominant drivers of soil microbial resource limitation. Furthermore, microbial resource limitation was a more reliable predictor of Rh than soil resources or microbial biomass. The results suggested that long-term N and BC additions affect Rh by regulating microbial resource limitation, highlighting its significance in understanding soil C cycling under environmental change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The accelerated warming in the world's highlands has prompted significant ecological adjustments and an increase in the frequency of forest fires. Nevertheless, the correlation between woody biomass and increased fire activity in the past has received limited attention. A total of 138 charcoal and 145 pollen records were analyzed to investigate the relationship between fire and woody biomass (arboreal pollen, AP) in the world's highlands during the Holocene. The findings indicate biomass burning in the Rockies, Alps and Andes stepped increased in the early to middle Holocene but decreased in the late Holocene. The positive AP-fuel feedback was recorded in the early-middle Holocene, whereas the negative AP-fuel feedback emerged in the late Holocene, the latter were attributed to denser forests in the Rockies and intensified human activities in the Alps and Andes. Conversely, Holocene biomass burning in the Tianshan-Altai Mountains, Africa and Tibetan Plateaus exhibited overall decreasing trends with sudden decreases in the Tianshan-Altai Mountains and Tibetan Plateau and a notable increase in the African Plateau over the past millennium. The variability observed in fire regime changes in the past millennium is likely influenced by human activities. Results illustrate that fire responses to woody vegetation are nonlinear, such that the same direction of change in vegetation can elicit different fire responses depending on their components at a site. Our study offers crucial insights into the influence of woody biomass on fire dynamics in the world's highlands, providing important contextual information about how these montane systems may respond to future climate change and anthropogenic activity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Healthy soils provide valuable ecosystem services (ES), but soil contamination can inhibit essential soil functions (SF) and pose risks to human health and the environment. A key advantage of using gentle remediation options (GRO) is the potential for multifunctionality: to both manage risks and improve soil functionality. In this study, an accessible, scientific method for soil health assessment directed towards practitioners and decision-makers in contaminated land management was developed and demonstrated for a field experiment at a DDX-contaminated tree nursery site in Sweden to evaluate the relative effects of GRO on soil health (i.e., the 'current capacity' to provide ES). For the set of relevant soil quality indicators (SQI) selected using a simplified logical sieve, GRO treatment was observed to have highly significant effects on many SQI according to statistical analysis due to the strong influence of biochar amendment on the sandy soil and positive effects of nitrogen-fixing leguminous plants. The SQI were grouped within five SF and the relative effects on soil health were evaluated compared to a reference state (experimental control) by calculating quantitative treated-SF indices. Multiple GRO treatments are shown to have statistically significant positive effects on many SF, including pollutant attenuation and degradation, water cycling and storage, nutrient cycling and provisioning, and soil structure and maintenance. The SF were in turn linked to soil-based ES to calculate treated-ES indices and an overall soil health index (SHI), which can provide simplified yet valuable information to decision-makers regarding the effectiveness of GRO. The experimental GRO treatment of the legume mix with biochar amendment and grass mix with biochar amendment are shown to result in statistically significant improvements to soil health, with overall SHI values of 141 % and 128 %, respectively, compared to the reference state of the grass mix without biochar (set to 100 %)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The increasing atmospheric CO 2 concentration is a global concern that affects the plant-bacteria-soil system. Previous studies have investigated plant growth and bacteria activity under CO 2 enrichment. However, the effects of coupled elevated CO 2 and biochar amendment on the interactions of soil and medicinal plants are not well understood. This study aims to investigate the medicinal plant-soil hydraulic interactions and rhizosphere bacteria communities under coupled CO 2 enrichment and biochar conditions. Two levels of CO 2 concentration (400, 1000 ppm) and two biochar dosages (3%, 5% by mass) were considered. Pseudostellaria heterophylla was used as the tested medicinal plant. During plant growth, coupled CO 2 enrichment and biochar at 3% and 5% dosage increased the volumetric water content at a matric suction of 33 kPa by 97% and 82% respectively, which indicates enhanced water retention. The transpiration rate of P. heterophylla was slightly reduced by 11-30% with an increase in biochar dosage due to higher total suction, while it was significantly reduced by up to 57% due to CO 2 enrichment. In the rhizosphere of P. heterophylla, elevated CO 2 (1000 ppm) coupled with 3% biochar dramatically increase the relative abundance of Thaumarchaeota, which played an important role in C and N cycles. Moreover, coupled CO 2 enrichment and biochar addition resulted in the highest bacterial richness, while 3% biochar at ambient CO 2 induced the highest bacterial diversity. This study provides a basis for understanding the medicinal plant-bacteria-soil system under CO 2 enrichment and biochar conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Soil thallium (Tl) contamination is of major public concern but little is known about soil Tl ecological toxicity or potential ecological remediation strategies. Here, two soil animal species with different ecological niches, Folsomia candida and Enchytraeus crypticus, were used to test Tl toxicity and modification by exogenous organic materials (i.e. maize straw and biochar). The endpoints of Tl ecotoxicity to F. candida and E. crypticus were studied at two biological levels, i.e., the individual (body Tl concentrations) and the population (survival, reproduction, and growth). Thallium concentrations in F. candida and E. crypticus increased with increasing soil Tl concentration, and their survival and reproduction rates decreased with increasing soil Tl concentration. The LC50 value of Tl effects on F. candida mortality (28 d) was 24.0 mg kg -1 and the EC50 value of reproduction inhibition was 6.51 mg kg -1 . The corresponding values were 4.15 mg kg -1 and 2.31 mg kg -1 respectively for E. crypticus showing higher sensitivity to soil Tl than F. candida. These effective values are comparable to or much lower than the environmental Tl concentrations in field soils, suggesting high potential ecological risk. Both biochar and straw can decrease animal body Tl concentrations in different ways, i.e. reducing Tl availability or offering clean food sources, and addition of exogenous organic materials clearly mitigated Tl ecotoxicity in highly polluted soil. The results highlight the potential Tl ecological risk to soil animals and the potential use of organic materials to control the toxicity., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The Mediterranean basin is highly susceptible to climate change, with soil salinization and the increase in average temperatures being two of the main factors affecting crop productivity in this region. Following our previous studies on describing the detrimental effects of heat and salt stress co-exposure on tomato plants, this study aimed to understand if substrate supplementation with a combination of arbuscular mycorrhizal fungi (AMF) and biochar could mitigate the negative consequences of these stresses. Upon 21 days of exposure, stressed tomato plants grown under supplemented substrates showed increased tolerance to heat (42 °C for 4 h/day), salt (100 mM NaCl), and their combination, presenting increased biomass and flowering rate. The beneficial effects of AMF and biochar were associated with a better ionic balance (i.e. lower sodium accumulation and higher uptake of calcium and magnesium) and increased photosynthetic efficiency. Indeed, these plants presented higher chlorophyll content and improved CO 2 assimilation rates. Biochemical data further supported that tomato plants grown with AMF and biochar were capable of efficiently modulating their defence pathways, evidenced by the accumulation of proline, ascorbate, and glutathione, coupled with a lower dependency on energy-costly enzymatic antioxidant players. In summary, the obtained data strongly point towards a beneficial role of combined AMF and biochar as sustainable tools to improve plant growth and development under a climate change scenario, where soil salinization and heat peaks often occur together., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Biochar and organic fertilizer are commonly used to maintain soil health and sustainable agroecosystems, and the alternate wet-dry management of soil moisture in dry direct-seeded paddy fields can complicate the effects of biochar and organic fertilizer on soil microhabitats. Therefore, this study used chicken manure organic fertilizer to replace some of the inorganic fertilizer and applied biochar to explore the ability of biochar and organic fertilizer to regulate the functions of the soil microhabitat in dry direct-seeded paddy fields. The coupling effect of organic fertilizer and biochar increased the diversity and richness of soil bacteria but had no significant effect on soil fungi. Biochar and organic fertilizer affected the distribution and composition of soil bacteria and fungi, and the total number of soil bacteria and fungi increased by 1365 and -71 (5 t/hm 2 biochar and no organic fertilizer), 660 and 79 (10 t/hm 2 biochar and no organic fertilizer), 3121 and 7 (no biochar and 20 % organic fertilizer substitution), 1873 and -72 (5 t/hm 2 biochar and 20 % organic fertilizer substitution), and -544 and -65 (10 t/hm 2 biochar and 20 % organic fertilizer substitution), respectively, compared with that of the control treatment. Compared with the application of biochar alone, the coupling effect of biochar and organic fertilizer increased the average degree (0.95 and 0.16), links (190 and 32), and ratio of fungal positive links (1.651 %), and decreased the modularity (0.034 and 0.052) and ratio of bacterial positive links (6.482 %) of bacterial and fungal networks. In addition, the coupling effect resulted in a more complex association between soil microbial diversity and richness and microbial ecological functions. Random forest predictions indicated that, organic fertilizer as a random factor, changes in the abundance of bacterial Bacteroidetes and Nitrospirae and fungal Monoblepharomycota were the main factors driving the differences in soil microbial ecological functions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

With an increase of diverse contaminants in the environment, particularly antibiotics, the maintenance and propagation of antibiotic resistance genes (ARGs) are promoted by co-selection mechanisms. ARGs are difficult to degrade, cause long-lasting pollution, and are widely transmitted in aquatic environments. Biochar is frequently used to remove various pollutants during environmental remediation. Thus, this review provides a thorough analysis of the current state of ARGs in the aquatic environment as well as their removal by using biochar. This article summarizes the research and application of biochar and modified biochar to remove ARGs in aquatic environments, in order to refine the following contents: 1) fill gaps in the research on the various ARG behaviors mediated by biochar and some influence factors, 2) further investigate the mechanisms involved in effects of biochar on extracellular ARGs (eARGs) and intracellular ARGs (iARGs) in aquatic environments, including direct and the indirect effects, 3) describe the propagation process and resistance mechanisms of ARGs, 4) propose the challenges and prospects of feasibility of application and subsequent treatment in actual aquatic environment. Here we highlight the most recent research on the use of biochar to remove ARGs from aquatic environments and suggest future directions for optimization, as well as current perspectives to guide future studies on the removal of ARGs from aquatic environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Excessive heavy metals in soils can threaten food security and soil health. New practical technology is urgently needed to remediate cadmium (Cd) contaminated paddies in many parts of the world. Chinese milk vetch (M), rice straw (R), and soil amendments can reduce Cd activity in soil; however, the mechanism underlying this reduction is not well understood. This study explored the impact of co-incorporation of milk vetch, rice straw, and either lime (L), sesbania biochar (B), or sepiolite on soil Cd bioavailability through field experiments. The results indicated that the rice grain Cd concentrations in soil treated with milk vetch + rice straw + fertilizer (MRF, 16.6 %), milk vetch + rice straw + fertilizer + sesbania biochar (MRFB, 50.1 %), and milk vetch + rice straw + fertilizer + lime (MRFL, 48.3 %) were significantly lower than those in soil treated with fertilizer (F). The acid-soluble Cd concentrations influenced rice grain Cd uptake and were 33.9 % and 47.5 % lower for the MRFB and MRFL treatments, respectively, than for F alone. A decrease in acid-soluble Cd (AciCd) was accompanied by a decrease in Eh and increases in pH, Fe 2+ , cation exchange capacity, and dissolved organic carbon. The MRFB treatment promoted iron plaque (IP) formation on the rice root surface. The relative abundances of Desulfobacterota and Verrucomicrobiota were higher for the MRFB treatment than for the other treatments. A partial least squares path model confirmed that Aci-Cd and low-crystalline IP (IP-Feh) influenced the rice grain Cd concentration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Agricultural application of pyrolysis‑carbonized perishable wastes can target reduction treatment and resource utilization of the wastes. However, potential undesirable impact has rarely been assessed. In this study, the adverse effect of perishable waste biochars (PWB) from different pyrolysis temperatures on Escherichia coli (E. coli) was explored and the potential risk factors were further analyzed. The results showed that PWBs pyrolyzed at 350, 500, and 650 °C inhibited the growth of E. coli, and PWB pyrolyzed at 500 °C showed the most inhibition. The exposure to PWB damaged the antioxidative system, as revealed by the concentration-dependent increasing of intracellular ROS. In addition, the toxicity at the gene level in terms of cell division and growth inhibition, the damage of cell membrane, antioxidant system disturbance, and DNA damage occurred, resulting in loss of the cell rules of morphology and eventual death. According to our results, the inhibitory effect on the growth of E. coli was mainly caused by PWB solids, accounting for >70 %. The membrane disruption and oxidative damage of E. coli by PWB were possibly induced by the direct physical interaction between cell and char particles. The growth of E. coli can be partly influenced by PWB extraction solutions that varied between PWB types, due to the differences in pH, released DOC and the production of extracellular ∙OH. The exploration of these potential hazards could provide new insights into the fate and toxicity of PWB in the environment and help guide the safe and sustainable applications for PWB., Competing Interests: Declaration of competing interest The authors declare that there are no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Peanut yield and quality face significant threats due to climate change and soil degradation. The potential of biochar technology to address this challenge remains unanswered, though biochar is acknowledged for its capacity to enhance the soil microbial community and plant nitrogen (N) supply. A field study was conducted in 2021 on oil peanuts grown in a sand-loamy Primisol that received organic amendments at 20 Mg ha -1 . The treatments consisted of biochar amendments derived from poultry manure (PB), rice husk (RB), and maize residue (MB), as well as manure compost (OM) amendment, compared to no organic amendment (CK). In 2022, during the second year after amendment, samples of bulk topsoil, rooted soil, and plants were collected at the peanut harvest. The analysis included the assessment of soil quality, peanut growth traits, microbial community, nifH gene abundance, and biological N fixation (BNF) rate. Compared to the CK, the OM treatment led to an 8 % increase in peanut kernel yield, but had no effect on kernel quality in terms of oil production. Conversely, both PB and MB treatments increased kernel yield by 10 %, whereas RB treatment showed no change in yield. Moreover, all biochar amendments significantly improved oilseed quality by 10-25 %, notably increasing the proportion of oleic acid by up to 70 %. Similarly, while OM amendment slightly decreased root development, all biochar treatments significantly enhanced root development by over 80 %. Furthermore, nodule number, fresh weight per plant, and the nifH gene abundance in rooted soil remained unchanged under OM and PB treatments but was significantly enhanced under RB and MB treatments compared to CK. Notably, all biochar amendments, excluding OM, increased the BNF rate and N-acetyl-glucosaminidase activity. These changes were attributed to alterations in soil aggregation, moisture retention, and phosphorus availability, which were influenced by the diverse physical and chemical properties of biochars. Overall, maize residue biochar contributed synergistically to enhancing soil fertility, peanut yield, and quality while also promoting increased root development, a shift in the diazotrophic community and BNF., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Biochar, a widely used material for soil amendment, has been found to offer numerous advantages in improving soil properties and the habitats for soil microorganisms. However, there is still a lack of global perspectives on the influence of various levels of biochar addition on soil microbial diversity and primary components. Thus, in our study, we performed a global meta-analysis of studies to determine how different doses of biochar affect soil total carbon (C), nitrogen (N), pH, alpha- and beta-diversity, and the major phyla of both bacterial and fungal communities. Our results revealed that biochar significantly increased soil pH by 4 %, soil total C and N by 68 % and 22 %, respectively, in which the positive effects increased with biochar doses. Moreover, biochar promoted soil bacterial richness and evenness by 3-8 % at the biochar concentrations of 1-5 % (w/w), while dramatically shifting bacterial beta-diversity at the doses of >2 % (w/w). Specifically, biochar exhibited significantly positive effects on bacterial phyla of Acidobacteria, Bacteroidetes, Gemmatimonadetes, and Proteobacteria, especially Deltaproteobacteria and Gammaproteobacteria, by 4-10 % depending on the concentrations. On the contrary, the bacterial phylum of Verrucomicrobia and fungal phylum of Basidiomycota showed significant negative responses to biochar by -8 % and -24 %, respectively. Therefore, our meta-analysis provides theoretical support for the development of optimized agricultural management practices by emphasizing biochar application dosing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Climate change, food insecurity, and agricultural pollution are all serious challenges in the twenty-first century, impacting plant growth, soil quality, and food security. Innovative techniques are required to mitigate these negative outcomes. Toxic heavy metals (THMs), organic pollutants (OPs), and emerging contaminants (ECs), as well as other biotic and abiotic stressors, can all affect nutrient availability, plant metabolic pathways, agricultural productivity, and soil-fertility. Comprehending the interactions between root exudates, microorganisms, and modified biochar can aid in the fight against environmental problems such as the accumulation of pollutants and the stressful effects of climate change. Microbes can inhibit THMs uptake, degrade organic pollutants, releases biomolecules that regulate crop development under drought, salinity, pathogenic attack and other stresses. However, these microbial abilities are primarily demonstrated in research facilities rather than in contaminated or stressed habitats. Despite not being a perfect solution, biochar can remove THMs, OPs, and ECs from contaminated areas and reduce the impact of climate change on plants. We hypothesized that combining microorganisms with biochar to address the problems of contaminated soil and climate change stress would be effective in the field. Despite the fact that root exudates have the potential to attract selected microorganisms and biochar, there has been little attention paid to these areas, considering that this work addresses a critical knowledge gap of rhizospheric engineering mediated root exudates to foster microbial and biochar adaptation. Reducing the detrimental impacts of THMs, OPs, ECs, as well as abiotic and biotic stress, requires identifying the best root-associated microbes and biochar adaptation mechanisms., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Sudhir K Upadhyay reports was provided by Veer Bahadur Singh Purvanchal University. Sudhir K. Upadhyay reports a relationship with Veer Bahadur Singh Purvanchal University that includes: employment. Sudhir K Upadhyay has patent NA pending to NA. All authors (Himanshu K. Pathak, Prabhat K. Chauhan, Chandra Shekhar Seth, Gopal Dubey, Sudhir K. Upadhyay) have no conflict of interest that appeared in this work. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Environmental pollution of heavy metal(loid)s (HMs) caused adverse impacts, has become one of the emerging concerns and challenges worldwide. Metal(loid)s can pose significant threats to living organisms even when present in trace levels within environmental matrices. Extended exposure to these substances can lead to adverse health consequences in humans. Removing HM-contaminated water and moving toward sustainable development goals (SDGs) is critical. In this mission, biochar has recently gained attention in the environmental sector as a green and alternative material for wastewater removal. This work provides a comprehensive analysis of the remediation of typical HMs by biochars, associated with an understanding of remediation mechanisms, and gives practical solutions for ecologically sustainable. Applying engineered biochar in various fields, especially with nanoscale biochar-aided wastewater treatment approaches, can eliminate hazardous metal(loid) contaminants, highlighting an environmentally friendly and low-cost method. Surface modification of engineered biochar with nanomaterials is a potential strategy that positively influences its sorption capacity to remove contaminants. The research findings highlighted the biochars' ability to adsorb HM ions based on increased specific surface area (SSA), heightened porosity, and forming inner-sphere complexes with oxygen-rich groups. Utilizing biochar modification emerged as a viable approach for addressing lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), and chromium (Cr) pollution in aqueous environments. Most biochars investigated demonstrated a removal efficiency >90 % (Cd, As, Hg) and can reach an impressive 99 % (Pb and Cr). Furthermore, biochar and advanced engineered applications are also considered alternative solutions based on the circular economy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this study, a high-solid anaerobic membrane bioreactor was established for treating food waste, and membrane fouling rates were regulated through multivariate modulation. The anaerobic membrane bioreactor operated stably at a high organic loading rate of 28.75 gCOD/L/d achieved a methane production rate of 8.03 ± 0.61 L/L/d. Experimental findings revealed that the most effective control of membrane fouling was achieved at a filtration- relaxation ratio (F/R) of 10/90 s. This indicates that a higher relaxation frequency provided improved the mitigation of membrane fouling. Compared with single F/R modulation, the combined modulation of biochar and F/R provided enhanced control over membrane fouling. Moreover, the addition of biochar altered the sludge properties of the reactor, thereby preventing the formation of a dense cake layer. Additionally, biochar enhanced the sheer force of the fluid on the membrane surface and facilitated the separation of pollutants during the relaxation stage, thereby contributing to improved control of membrane fouling., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Intercropping legume with grass has potential to increase biomass and protein yield via biological N 2 -fixation (BNF) benefits, whereas the joint effects of biochar (BC) coupled with deficit irrigation on intercropping systems remain elusive. A 15 N isotope-labelled experiment was implemented to investigate morpho-physiological responses of faba bean-ryegrass intercrops on low- (550 °C, LTBC) or high-temperature BC (800 °C, HTBC) amended sandy-loam soil under full (FI), deficit (DI) and partial root-zone drying irrigation (PRD). LTBC and HTBC significantly reduced intrinsic water-use efficiency (WUE) by 12 and 14 %, and instantaneous WUE by 8 and 16 %, respectively, in faba bean leaves, despite improved photosynthetic (A n ) and transpiration rate (T r ), and stomatal conductance (g s ). Compared to FI, DI and PRD lowered faba bean A n , g s and T r , but enhanced leaf-scale and time-integrated WUE as proxied by the diminished shoots Δ 13 C. PRD enhanced WUE as lower g s , T r and guard cell length than DI-plants. Despite higher carbon ([C]) and N concentration ([N]) in faba bean shoots amended by BC, the aboveground C- and N-pool of faba bean were reduced, while these pools increased for ryegrass. The N-use efficiency (NUE) in faba bean shoots was reduced by 9 and 14 % for LTBC and HTBC, respectively, but not for ryegrass. Interestingly, ryegrass shoots had 52 % higher NUE than faba bean shoots. The N derived from atmosphere (% Ndfa) was increased by 2 and 9 % under LTBC and HTBC, respectively, while it decreased slightly by reduced irrigation. Quantity of BNF in faba bean aboveground biomass decreased with HTBC coupled with reduced irrigation, mainly towards decreased biomass and soil N uptake by faba bean. Therefore, HTBC might not be a feasible option to improve WUE and BNF in faba bean-ryegrass intercropping, but PRD is permissible as the clear trade-off between BC and PRD., Competing Interests: Declaration of competing interest The authors declare no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The utilization of solar energy and fast-growing heterotrophic microbes for biofuel production has been recognized as a promising approach to achieve carbon neutrality and address energy crisis. In this work, we synthesized different kinds of photocatalysts based on graphitic carbon nitride (g-C 3 N 4 ). We found that carbon dots modified-graphitic carbon nitride (CDs-g-C 3 N 4 ) showed the highest photocatalytic activity. Subsequently, we developed a photocatalyst-microbe hybrid (PMH) system by combining CDs-g-C 3 N 4 with an oleaginous yeast strain, Cutaneotrichosporon dermatis ZZ-46. Under visible light irradiation, the lipid yield of this PMH system reached 1.70 g/L at 120 h, representing a 36 % increase compared to the control. The photocatalytic reaction-induced ROS and the reductive photogenerated electrons facilitated ZZ-46 cells to synthesize more lipids. Furthermore, the fermentation residual of this PMH system was reutilized to prepare biochar via pyrolysis. The biochar generated at 550 °C (BC-550) demonstrated exceptional adsorption capabilities, particularly with a 57 % adsorption rate for methylene blue (MB), and maintained its perfect adsorption efficacy even after five regeneration cycles. These results offer promising avenues for addressing energy shortages and environmental contamination., Competing Interests: Declaration of competing interest No potential conflict of interest was reported by the authors., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Biofouling limits applications of membrane technology in wastewater treatment, but dosing additives to membrane tanks is an effective method to alleviate biofouling. In this study, biochar derived from corncob and pyrolyzed at 300, 500, and 700°C was dosed to determine the underlying anti-biofouling mechanism. The effects of the biochar on the membrane properties and foulant behavior were systematically investigated. The results showed that biochar delayed the occurrence of the fouling transition (0.5-3.0 h), and decreased the flux decline rate, thus achieving a higher water flux (3.1-3.7 times of the control group). Biochar altered membrane surface properties, and increased the membrane surface charge, roughness, and hydrophilicity, which all contributed to higher membrane permeability. Moreover, adding biochar reduced the number of foulants in the fouling layer, particularly protein substances. The flux model fit and the XDLVO theory further revealed the mitigating effect of biochar on membrane biofouling. At the initial intermediate-blocking stage, the effect of biochar on membrane fouling was determined by its properties, and adsorption capacity to the foulants, BC500 presented the best mitigation performance. At the later cake-filtration stage, the role of biochar in membrane fouling was strongly associated with protein content in the fouling layer, and the minimum rate of flux decline occurred in BC300. This study promotes the understanding and development of biochar to alleviate membrane biofouling., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

As a novel agricultural practice, the reuse of food waste compost and digestate as fertilizers leads to a circular economy, but inevitably introduces bio-contaminants such as antibiotic resistance genes (ARGs) into the agroecosystem. Moreover, heavy metal and antibiotic contamination in farmland soil may exert selective pressures on the evolution of ARGs, posing threats to human health. This study investigated the fate, influencing mechanisms and potential risks of ARGs in a soil-vegetable system under different food waste fertilization and remediation treatments and soil contamination conditions. Application of food waste fertilizers significantly promoted the pakchoi growth, but resulted in the spread of ARGs from fertilizers to pakchoi. A total of 56, 80, 84, 41, and 73 ARGs, mobile genetic elements (MGEs) and metal resistance genes (MRGs) were detected in the rhizosphere soil (RS), bulk soil (BS), control soil (CS), root endophytes (RE), and leaf endophytes (LE), respectively. Notably, 7 genes were shared in the above five subgroups, indicating a specific soil-root-endophytes transmission pathway. 36 genes were uniquely detected in the LE, which may originate from airborne ARGs. The combined application of biochar and fertilizers reduced the occurrence of ARGs and MGEs to some extent, showing the remediation effect of biochar. The average abundance of ARGs in the RS, BS and CS was 3.15 × 10 -2 , 1.31 × 10 -2 and 2.35 × 10 -1 , respectively. Rhizosphere effects may reduce the abundance of ARGs in soil. The distribution pattern of ARGs was influenced by the types of soil, endophyte and contaminant. MGEs is the key driver shaping ARGs dynamics. Soil properties and pakchoi growth status may affect the bacterial composition, and consequently regulate ARGs fate, while endophytic ARGs were more impacted by biotic factors. Moreover, the average daily doses of ARGs from pakchoi consumption is 10 7 -10 9  copies/d/kg, and its potential health risks should be emphasized., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Endophytic fungi (Trichoderma harzianum (TH) and Paecilomyces lilacinus (PL)) showed potential in phytoremediation for soils contaminated with potentially toxic elements (PTEs (Cd and As)). However, their efficiency is limited, which can be enhanced with the assistance of biochar. This study sought to investigate the effects of TH at two application rates (T1: 4.5 g m -2 ; T2: 9 g m -2 ), PL at two application rates (P1: 4.5 g m -2 ; P2: 9 g m -2 ), in conjunction with biochar (BC) at 750 g m -2 on the phytoremediation of PTEs by Miscanthus sinensis (M. sinensis). The results showed that the integration of endophytic fungi with biochar notably enhanced the accumulation of Cd and As in M. sinensis by 59.60 %-114.38 % and 49.91 %-134.60 %, respectively. The treatments T2BC and P2BC emerged as the most effective. Specifically, the P2BC treatment significantly enhanced the soil quality index (SQI > 0.55) across all examined soil layers, markedly improving the overall soil condition. It was observed that T2BC treatment could elevate the SQI to 0.56 at the 0-15 cm depth. The combined amendment shifted the primary influences on plant PTEs accumulation from fungal diversity and soil nutrients to bacterial diversity and the availability of soil PTEs. Characteristic microorganisms identified under the combined treatments were RB41 and Pezizaceae, indicating an increase in both bacterial and fungal diversity. This combination altered the soil microbial community, influencing key metabolic pathways. The combined application of PL and biochar was superior to the TH and biochar combination for the phytoremediation of M. sinensis. This approach not only enhanced the phytoremediation potential but also positively impacted soil health and microbial community, suggesting that the synergistic use of endophytic fungi and biochar is an effective strategy for improving the condition of alkaline soils contaminated with PTEs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

We present a soil manufactured from waste materials, which could replace the use of peat and topsoil in plant production and reduce the pressure on natural soil resources. We tested the effect of the manufactured soil on ecosystem functions and microbial communities with and without plants present, and with and without biochar addition (Experiment 1). The resilience of the soil in response to drought and flooding, and also the effect of biochar was also tested (Experiment 2). Biochar increased soil C and N regardless of plant presence and negated the effect of the plant on soil peroxidase enzyme activity. The manufactured soil was largely resilient to drought, but not flooding, with negative impacts on microbial communities. Results indicate that biochar could improve soil properties, but not resilience to climatic perturbations. Results suggest that manufactured soils amended with biochar could offer a useful alternative to natural soil in many contexts., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Mark F. Fitzsimons reports financial support was provided by University of Plymouth. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

DOM (dissolved organic matter) play a crucial role in lakes' geochemical and carbon cycles. Eutrophication evolution would influence nutrient status of waters and investigating the DOM variation helps a better understanding of bioremediation on environmental behavior of DOM in eutrophic lakes. In our study, the contents, compositions and characteristics of systematic DOM&SOM (sediment organic matter) were greatly influenced by seasonal changes. But the effective bioremediations obviously reduced the DOM concentration and thus mitigated the eutrophication outbreak risks in water bodies due to the increased MBC (microbial biomass carbon), microbial activity and metabolism. In early summer, the overall DOM in each treatment were readily low levels and derived from both autochthonous and exogenous origins, dominated by fulvic acid-like. In midsummer, the DOM contents and characteristics in each treatment increased significantly as phytoplankton activity improved, and the majority of DOM were humic acid-like and mainly of biological origin. The greatest differences of enzymes, MBC, microbial metabolism and DOM&SOM removal among different treatments were observed in summer months. In autumn, the systematic DOM&SOM slightly reduced due to the deceased microbial activity, in which the microbial humic acids were main component and derived from endogenous sources. Additionally, the gradually decreased SOM with cultivated time in each treatment was a result of microbiological conversion of SOM into DOM. For various treatments, BE, BE.A, BE.C and BE.E increased the MBC, enzymatic and microbial activities due to the application of biochar-supported EMs. Among these, BE and BE.A, especially BE.A with oxygen supplement, achieved the most desirable effect on reducing systematic DOM&SOM levels and increasing enzymatic and microbial activities. The group of EM also reduced the levels of DOM&SOM as improved degradation of EMs for DOM. However, BC, BE.C and BE.E finally did not achieved the desirable effect on reducing DOM&SOM due to the suppression of microbial activities, respectively, from high dose of biochar, weakening of dominant species and additional introduction of EMs in low liveness., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Sequential utilization of ozone (O 3 ) and biological activated carbon (BAC) followed by UV/chlor(am)ine advanced oxidation process (AOP) has drawn attention in water reuse. However, the formation of disinfection by-products (DBPs) in this process is less evaluated. This study investigated the DBP formation and the relevant toxicity during the O 3 -BAC-UV/chlor(am)ine treatment of sand-filtered municipal secondary effluent. DBP formation in UV/chlorine and UV/dichloramine (NHCl 2 ) processes were compared, where the impact of key operational parameters (e.g., UV wavelength, pH) on DBP formation were comprehensively evaluated. O 3 -BAC significantly reduced DBP formation potential (DBPFP) (58.2 %). Compared to UV/chlorine AOP, UV/NHCl 2 AOP reduced DBP formation by 29.7 % in short-time treatment, while insignificantly impacting on DBPFP (p > 0.05). UV/NHCl 2 AOP also led to lower calculated cytotoxicity (67.7 %) and genotoxicity (55.9 %) of DBPs compared to UV/chlorine AOP. Compared to 254 nm UV light, the utilization of 285 nm UV light decreased the formation of DBPs in wastewater treated with the UV/chlorine AOP and UV/NHCl 2 AOP by 31.3 % and 19.2 %, respectively. However, the cytotoxicity and genotoxicity in UV/NHCl 2 AOP using 285 nm UV light increased by 83.4 % and 58.5 %, respectively, compared to 254 nm. The concentration of DBPs formed in the UV/NHCl 2 AOP at pH 8 was 54.3 % lower than that at pH 7, suggesting a better control of DBPs at alkaline condition. In the presence of bromide, UV/NHCl 2 AOP tended to generate more brominated DBPs than UV/chlorine AOP. Overall, UV/NHCl 2 AOP resulted in lower concentration and toxicity of DBPs compared to UV/chlorine AOP., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The agricultural sector faces severe challenges owing to heavy metal (HM) contamination of farmlands, requiring urgent preventive measures. To address this, we investigated the impact of the synergistic application of Azospirillum brasilense, a growth-promoting rhizobacterium producing abscisic acid (ABA), and biochar to minimize HM accumulation in pak choi, using three distinct expression levels of the ABA transporter NRT1.2 in pak choi and three different types of contaminated soils as experimental materials. The results revealed that pak choi with low, medium, and high NRT1.2 expression intensity, when subjected to bacterial strain-biochar treatment, exhibited an increasing trend in ABA content compared to the control. Correspondingly, the aboveground HM content decreased by 1-49 %, 22-52 %, and 15-96 %, whereas the fresh weight increased by 12-38 %, 88-126 %, and 152-340 %, respectively, showing a significant correlation with NRT1.2 expression. Pearson correlation analysis demonstrated that NRT1.2 expression intensity was inversely associated with the combined treatment's reduction in HM accumulation and positively correlated with the promotional effect. Simultaneously, soil discrepancies significantly affected the combined treatment, which was likely associated with variations in the active forms of HM in each soil. Consequently, when employing ABA-producing bacteria for mitigating crop HM accumulation, selecting plants with higher relative NRT1.2 expression intensity, combined with biochar, is recommended., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Soil contamination by Cr(VI) has attracted widespread attention globally in recent years, but it remains a significant challenge in developing an environmentally friendly and eco-sustainable technique for the disposal of Cr(VI)-contaminated soil. Herein, a sustainable cyclic soil washing system for Cr(VI)-polluted soil remediation and the recovery of washing agents using biochar supported nanoscale zero-valent iron (nZVI-BC) was established. Citric acid (CA) was initially screened to desorb Cr(VI) from contaminated soil, mobilizing Cr from the highly bioaccessible fractions. The nZVI-BC exhibited superior properties for Cr(VI) and Cr(total) removal from spent effluent, allowing effective recovery of the washing agents. The elimination mechanism of Cr(total) by nZVI-BC involved the coordinated actions of electrostatic adsorption, reduction, and co-precipitation. The contributions to Cr(VI) reduction by Fe 0 , surface-bound Fe(II), and soluble Fe(II) were 0.6 %, 39.8 %, and 59.6 %, respectively. Meanwhile, CA favored the activity of surface-bound Fe(II) and Fe 0 in nZVI-BC, enhancing the production of soluble Fe(II) to strengthen Cr(VI) removal. Finally, the recovered washing agent was proven to be reused three times. This study showcases that the combined soil washing using biodegradable chelant CA and effluent treatment by nZVI-BC could be a sustainable and promising strategy for Cr(VI)-contaminated soil remediation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Torrefaction is an effective pathway for microalgal solid biofuel upgrading, and alkali metal activation is also an efficient method to enhance fuel properties. This study explores the comparison of torrefaction alone and KOH activation combined with torrefaction to determine a better operation for biochar production from the microalga Nannochloropsis Oceanica. The results indicate that the HHV ranges of KOH-activated biochar and unactivated biochar are 25.611-32.792 MJ·kg -1 and 25.024-26.389 MJ·kg -1 , respectively. Furthermore, KOH-activated biochar is better than unactivated biochar, with less residue, broader pyrolysis and combustion temperature ranges, higher elemental carbon, and less combined carbon. Moreover, KOH-activated biochar is close to the unactivated one from the viewpoint of expense calculation and life cycle assessment and thus possesses a better comprehensive performance. Overall, KOH activation is an efficient method for upgrading microalgal solid biofuel. The results are conducive to exploring further modification of microalgal solid biofuel production with better properties, thus leading to a greener and more efficient approach for upgrading fuel performance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The major challenges for the current climate change issue are an increase in global energy demand, a limited supply of fossil fuels, and increasing carbon footprints from fossil fuels, which have necessitated the exploration of sustainable alternatives to fossil fuels. Biorefineries offer a promising path to sustainable fuel production, converting biomass into biofuels using diverse technologies. Aquatic biomass, such as macroalgae in this context, represents an abundant and renewable biomass resource that can be cultivated from water bodies without competing with traditional agricultural land. Despite this, the potential of macroalgae for biofuel production remains largely untapped, with very limited studies addressing their viability and efficiency. This study investigates the efficient conversion of unexplored macroalgae biomass through a biorefinery process that involves lipid extraction to produce biodiesel, along with the production of biochar and bio-oil from the pyrolysis of residual biomass. To improve the effectiveness and overall performance of the pyrolysis system, Response Surface Methodology (RSM) was utilized through a Box-Behnken design to systematically investigate how alterations in temperature, reaction time, and catalyst concentration influence the production of bio-oil and biochar to maximize their yields. The results showed the highest bio-oil yield achieved to be 36 %, while the highest biochar yield reached 45 %. The integration of Life Cycle Assessment (LCA) in the study helps to assess carbon emission and environmental burdens and identify potential areas for optimization, such as resource efficiency, waste management, and energy utilization. The LCA results contribute to the identification of potential environmental hotspots and guide the development of strategies to optimize the overall sustainability of the biofuel production process. The LCA results indicate that the solvent (chloroform) used in transesterification contributes significantly to greenhouse gas emissions and climate change impacts. Therefore, it is crucial to explore alternative, safe solvents that can mitigate the environmental impacts of transesterification., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Biochar used for soil amendment is considered a viable negative emissions technology as it can be produced easily from a wide range of biomass feedstocks, while offering numerous potential agricultural benefits. This research is the first to present a comprehensive sustainability assessment of large-scale biochar production and application in Malaysia. The five feedstocks considered comprise the country's most abundant agricultural wastes from palm oil (empty fruit bunches, fibres, palm fronds and shells) and rice (straw) plantations. Combined with process simulation, life cycle assessment and life cycle costing are used to assess the sustainability of biochar production via slow pyrolysis at different temperatures (300-600 °C), considering two functional units: i) production and application of 1 t of biochar; and ii) removal of 1 t of CO 2 from the atmosphere. The cradle-to-grave system boundary comprises all life cycle stages from biomass acquisition to biochar use for soil amendment. The positive impacts of the latter, such as carbon sequestration, fertiliser avoidance and reduction in soil N 2 O emissions, are also included. The global warming potential (GWP) is net-negative in all scenarios, ranging from -436 to -2,085 kg CO 2 eq./t biochar and -660 to -933 kg CO 2 eq./t CO 2 removed. Per t of biochar, the systems with shells have the lowest GWP and those with straw the highest, all showing better performance if produced at higher pyrolysis temperatures. However, the temperature trend is opposite for all other 17 impacts considered, with fibres being the best option and fronds the worst for most categories. Per t CO 2 removed, fronds have the highest impact in eight categories, including GWP, and shells the lowest in most categories. All impacts are lower for biochar production at higher temperatures. The main hotspot is the pyrolysis process, influencing the majority of impact categories and contributing 66-75 % to the life cycle costs. The costs range from US$116-197/t biochar and US$60-204/t CO 2 removed. The least expensive systems per t biochar are those with straws and per t CO 2 removed those with shells, while fronds are the worst option economically for both functional units. Utilising all available feedstocks could remove 6-12.4 Mt of CO 2 annually, reducing the national emissions from the agricultural sector by up to 54 % and saving US$36.05 M annually on fertilisers imports. These results will be of interest to policy makers in Malaysia and other regions with abundant agricultural wastes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

As global greenhouse gas emissions increase and fossil energy sources decline dramatically, the energy transition is at the heart of many countries' development initiatives. As a biomass resource, straw plays a positive role in energy transformation and environmental improvement. However, there is still a challenge to explore the best options and models for straw production and utilization of green and efficient biomass energy in agricultural systems. This study establishes an economic-environmental-resource synergistic Straw Green recycling optimization model based on straw-electricity-biochar-biogas core (Straw Green recycling optimization model, SGROM). Firstly, we explore the effects of biochar return to the field on crop yield and greenhouse gas emission by Meta-analysis method, and on this basis, we construct SGROM to weigh the three objectives of economic-greenhouse gas emission-resource utilization, and explore the best allocation ratio between four utilization methods of straw: power generation, biochar preparation, biogas and derivatives preparation and sale, so as to obtain a straw recycling and efficient low-carbon utilization model. Exploring the response of straw green utilization patterns to crop market prices with the help of deep learning methods, SGROM has been applied to the main grain producing areas in the Sanjiang Plain of China, and the results of comparison with the traditional straw utilization (TSU) model show that the greenhouse gas emissions per unit of production value of SGROM are 19.66 % lower than that of TSU model, the electricity consumption is saved by 2.00 %, and the optimal ratios of straw for power generation, biogas and biochar production, and sale are 1.00 %, 10.75 %, 62.11 % and 26.14 %. The economic benefits and total greenhouse gas emissions of the integrated straw utilization mode are better than those of the single straw utilization mode, proving the superiority of SGROM in optimizing the straw utilization mode., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Soil contamination with heavy metals has emerged as a global environmental threat, compromising agricultural productivity, ecosystem integrity, and human health. Conventional remediation techniques often fall short due to high costs, operational complexities, and environmental drawbacks. Plant-based disposal technologies, including biochar, phytometallurgy, and phrolysis, have emerged as promising solutions in this regard. Grounded in a novel experimental framework, biochar is studied for its dual role as soil amendment and metal adsorbent, while phytometallurgy is explored for its potential in resource recovery and economic benefits derived from harvested metal-rich plant biomass. Pyrolysis, in turn, is assessed for transforming contaminated biomass into value-added products, thereby minimizing waste. These plant disposal technologies create a circular model of remediation and resource utilization that holds the potential for application in large-scale soil recovery projects, development of environmentally friendly agro-industries, and advancement in sustainable waste management practices. This review mainly discussed cutting-edge plant disposal technologies-biochar application, phytometallurgy, and pyrolysis-as revolutionary approaches to soil heavy metal remediation. The efficacy, cost-effectiveness, and environmental impact of these innovative technologies are especially evaluated in comparison with traditional methods. The success of these applications could signal a paradigm shift in how we approach both environmental remediation and resource recovery, with profound implications for sustainable development and circular economy strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Biochar application is a promising practice to enhance soil fertility. However, it is unclear how field-aged biochar affects the soil metabolites and microbial communities in soybean fields. Here, the rhizosphere soil performance after amending with biochar addition rates at 0 (CK), 20 (B20), 40 (B40), and 60 t ha -1 (B60) was examined via a five-year in-situ field experiment based on a soybean continuous cropping system. Untargeted metabolomics and metagenomics analysis techniques were applied to study the regulatory mechanism of biochar on soybean growth from metabolomics and N cycle microbiology perspectives. We found that the contents of soil total N (TN), available N (Ava N), NH 4 + -N, and NO 3 - -N were significantly increased with biochar addition amounts by 20.0-65.7 %, 3.6-10.7 %, 29.5-57.1 %, and 24.4-46.7 %, respectively. The B20, B40, and B60 triggered 259 (236 were up-regulated and 23 were down-regulated), 236 (220 were up-regulated and 16 were down-regulated), and 299 (264 were up-regulated and 35 were down-regulated) differential metabolites, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and topology analysis demonstrated that differential metabolites were highly enriched in seven metabolic pathways such as Oxidative phosphorylation and Benzoxazinoid biosynthesis. Moreover, ten differential metabolites were up-regulated in all three treatments with biochar. Biochar treatments decreased the Nitrospira abundance in soybean rhizosphere soil while increasing Bradyrhizobium abundance significantly in B60. Mantel test revealed that as the biochar addition rate grows, the correlation between Nitrospira and soil properties other than NO 3 - -N became stronger. In conclusion, the co-application of biochar with fertilizers is a feasible and effective way to improve soil N supply, even though biochar has undergone field aging. This work offers new insights into the variations in soil metabolites and microbial communities associated with N metabolism processes under biochar addition in soybean continuous cropping soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Biochar was popularly used for reducing greenhouse gas (GHG) emissions in vegetable production, but using biochar does not necessarily guarantee a reduction in GHG emissions. Herein, it's meaningful to elucidate the intricate interplay among biochar properties, soil characteristics, and GHG emissions in vegetable production to provide valuable insights for informed and effective mitigation strategies. Therefore, in current research, a meta-analysis of 43 publications was employed to address these issues. The boost-regression analysis results indicated that the performance of biochar in inhibiting N 2 O emissions was most affected by the N application rate both in high and low N application conditions. Besides, biochar had dual roles and showed well performance in reducing GHG emissions under low N input (≤300 kg N ha -1 ), while having the opposite effect during high N input (>300 kg N ha -1 ). Specifically, applying biochar under low N fertilization input could obviously reduce soil N 2 O emissions, CO 2 emissions, and CH 4 emissions by 18.7 %, 17.9 %, and 16.9 %, respectively. However, the biochar application under high N fertilization input significantly (P < 0.05) increased soil N 2 O emissions, CO 2 emissions, and CH 4 emissions by 39.7 %, 43.0 %, and 27.7 %, respectively. Except for the N application rate, the soil pH, SOC, biochar C/N ratio, biochar pH, and biochar pyrolysis temperature are also the key factors affecting the control of GHG emissions in biochar-amended soils. The findings of this study will contribute to deeper insights into the potential application of biochar in regulating GHG under consideration of N input, offering scientific evidence and guidance for sustainable agriculture management., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024. Published by Elsevier B.V.)

Soil cadmium (Cd) pollution poses severe threats to food security and human health. Previous studies have reported that both nanoparticles (NPs) and biochar have potential for soil Cd remediation. In this study, a composite material (BN) was synthesized using low-dose TiO 2 NPs and silkworm excrement-based biochar, and the mechanism of its effect on the Cd-contaminated soil-pak choi system was investigated. The application of 0.5 % BN to the soil effectively reduced 24.8 % of diethylenetriaminepentaacetic acid (DTPA) Cd in the soil and promoted the conversion of Cd from leaching and HOAc-extractive to reducible forms. BN could improve the adsorption capacity of soil for Cd by promoting the formation of humic acid (HA) and increasing the cation exchange capacity (CEC), as well as activating the oxygen-containing functional groups such as CO and CO. BN also increased soil urease and catalase activities and improved the synergistic network among soil bacterial communities to promote soil microbial carbon (C) and nitrogen (N) cycling, thus enhancing Cd passivation. Moreover, BN increased soil biological activity-associated metabolites like T-2 Triol and altered lipid metabolism-related fatty acids, especially hexadecanoic acid and dodecanoic acid, crucial for bacterial Cd tolerance. In addition, BN inhibited Cd uptake and root-to-shoot translocation in pak choi, which ultimately decreased Cd accumulation in shoots by 51.0 %. BN significantly increased the phosphorus (P) uptake in shoots by 59.4 % by improving the soil microbial P cycling. This may serve as a beneficial strategy for pak choi to counteract Cd toxicity. These findings provide new insights into nanomaterial-doped biochar for remediation of heavy metal contamination in soil-plant systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The unrestricted release of various toxic substances into the environment is a critical global issue, gaining increased attention in modern society. Many of these substances are pristine to various environmental compartments known as contaminants/emerging contaminants (ECs). Nanoparticles and emerging sorbents enhanced remediation is a compelling methodology exhibiting great potential in addressing EC-related issues and facilitating their elimination from the environment, particularly those compounds that demonstrate eco-toxicity and pose considerable challenges in terms of removal. It provides a novel technique enabling the secure and sustainable removal of various ECs, including persistent organic compounds, microplastics, phthalate, etc. This extensive review presents a critical perspective on the current advancements and potential outcomes of nano-enhanced remediation techniques such as photocatalysis, nano-sensing, nano-enhanced sorbents, bio/phyto-remediation, which are applied to clean-up the natural environment. In addition, when dealing with residual contaminants, special attention is paid to both health and environmental implications; therefore, an evaluation of the long-term sustainability of nano-enhanced remediation methods has been considered. The integrated mechanical approaches were thoroughly discussed and presented in graphical forms. Thus, the critical evaluation of the integrated use of most emerging remediation technologies will open a new dimension in environmental safety and clean-up program., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Biochar application in rice production reduces nitrogen loss and greenhouse gases. We conducted in situ experiments for 3 years, with N 210 B 0 (210 kg N ha -1 ) as the control. Two biochar application methods (B 1 :15 t ha -1 biochar applied once and B 2 : biochar applied three times at 5 t ha -1  yr -1 ) combined with two nitrogen levels (N 210 : 210 kg N ha -1 and N 168 : 168 kg N ha -1 ) were used. Soil physicochemical properties, CH 4 and N 2 O emissions, functional gene abundance, rice yield, and nitrogen use efficiency were analyzed. Both methods improved the physicochemical properties of the soil, however, B 1 was less effective than B 2 in increasing soil pH, bulk density, organic carbon, total nitrogen, and microbial biomass nitrogen in year 3. B 1 had a higher CH 4 emission mitigation effect than B 2 in 3 consecutive years, mainly due to the higher pmoA gene abundance. B 1 showed a higher reduction effect of N 2 O emissions compared to B 2 in year 1, but the opposite was observed in years 2 and 3. B 2 had a higher abundance of AOB, nirK, and nosZ genes compared to B 1 in year 3. Compared with N 210 B 0 , rice yields were increased by 9.1 %, 9.6 %, and 3.6 % with N 210 B 1 , N 210 B 2, and N 168 B 2 , respectively, over 3 years, while N 168 B 1 improved yields in the previous 2 years. Biochar improved nitrogen use efficiency over 3 consecutive years directly due to increased use efficiency of panicle fertilizer; the effect of B 1 was greater than that of B 2 during years 1 and 2, while the opposite was observed in year 3. Both Biochar applied once and three times appeared to be promising practices to increase yield and mitigate GHGs. From the GHGI perspective, the biochar applied once combined with 168 kg N ha -1 can further improve nitrogen use efficiency, and reduce GHGs without hindering improvements in rice yield., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Research attention is growing for biochar as amendment for anaerobic digestion (AD), as it may improve both the AD process and digestate properties. In this study, two biochars (from insect frass or the woody fraction of green waste, both pyrolyzed at 450 °C) were added (5 % w/w) during semi-continuous AD of organic kitchen waste and chicken manure. Biochar was mixed either during the AD process or to the digestate post-treatment. The impact of biochar addition on the AD process, NH 3 and greenhouse gas emissions, as well as C and N mineralization following soil application, was examined. Biochar did not affect the biogas yield, but did lead to a reduction in NH 3 levels in the biogas and NH 4 + -N sorption onto the biochars, reducing the risk of AD inhibition. N sorbed as NH 4 + -N onto the biochar was more available for mineralization than N sorbed as NH 3 . N sorption on biochar-amended digestates did not result in trade-offs when these digestates were applied to soil: the sorbed N was not released as NH 3 or N 2 O after soil application and was not released as mineral N in either the short or medium term. The C-rich biochars increased the OC content of the digestate, which enhanced its value as soil improver. Additionally, mixing biochar with digestate decreased the soil CO 2 emissions up to 33 % when it was added after AD; no priming effects were observed. These findings highlight the potential benefits of incorporating biochar into AD systems and the subsequent application of biochar-amended digestate in agricultural practices., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Jarinda Viaene reports financial support was provided by Research Institute for Agriculture Fisheries and Food Research. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Point-of-use (POU) filters certified to remove lead are often composed of activated carbon and have been shown to release high concentrations of bacteria, including opportunistic pathogens. In this study, we examine the impacts of the common corrosion inhibitor phosphate on biofilm characteristics and the relationship between biofilm structure and bacterial release from POU filters. This knowledge is essential for understanding how best to use the filters and where these filters fit in a system where other lead contamination prevention measures may be in place. We measured the bacterial release from activated carbon POU filters fed with groundwater - a common source of drinking water - with and without phosphate. We used optical coherence tomography (OCT) to quantitatively characterize biofilm growing on activated carbon filter material in which the biofilms were fed groundwater with and without phosphate. Phosphate filters released significantly less (57-87 %) bacteria than groundwater filters, and phosphate biofilms (median thickness: 82-331 μm) grew to be significantly thicker than groundwater biofilms (median thickness: 122-221 μm). The phosphate biofilm roughness ranged from 97 to 142 % of the groundwater biofilm roughness and was significantly greater in most weeks. Phosphate biofilms also had fewer pores per biofilm volume and shorter channels connecting those pores., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Estuaries, as important land-ocean transitional zones across the Earth's surface, are hotspots of microbially driven dark carbon fixation (DCF), yet understanding of DCF process remains limited across the estuarine-coastal continuum. This study explored DCF activities and associated chemoautotrophs along the estuarine and coastal environmental gradients, using radiocarbon labelling and molecular techniques. Significantly higher DCF rates were observed at middle- and high-salinity regions (0.65-2.31 and 0.66-2.82 mmol C m -2 d -1 , respectively), compared to low-salinity zone (0.07-0.19 mmol C m -2 d -1 ). Metagenomic analysis revealed relatively stable DCF pathways along the estuarine-coastal continuum, primarily dominated by Calvin-Benson-Bassham (CBB) cycle and Wood-Ljungdahl (WL) pathway. Nevertheless, chemoautotrophic communities driving DCF exhibited significant spatial variations. It is worth noting that although CBB cycle played an important role in DCF in estuarine sediments, WL pathway might play a more significant role, which has not been previously recognized. Overall, this study highlights that DCF activities coincide with the genetic potential of chemoautotrophy and the availability of reductive substrates across the estuarine-coastal continuum, and provides an important scientific basis for accurate quantitative assessment of global estuarine carbon sink., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Soil co-contamination of potentially toxic elements (PTEs) and phthalate esters has become prominent due to its potential adverse effect on human food supply. There is limited information on using wood- and animal-derived biochars for the remediation of co-contaminated soils. Therefore, a pot experiment was conducted using Brassica chinensis L. as a bio-indicator plant to investigate the effect of P. orientalis biochar and pig biochar application on the bioavailability of cadmium (Cd) and di-(2-ethylhexyl) phthalate (DEHP) and on plant physiological parameters (malondialdehyde, proline and soluble sugars). Biochar materials were applied to two soils containing low (LOC) and high (HOC) organic carbon content at rates of 0, 0.5, 1, 2, and 4%. To better understand the influence of biochar, physicochemical properties and X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDS), Fourier transform-infrared spectrometry (FTIR), scanning electron microscopy (SEM) were characterized. Biochar application increased soil pH, organic carbon content, and available phosphorus content. Increasing biochar application rates decreased DTPA-extractable Cd and extractable DEHP concentrations in both soils. Biochar application reduced the plant uptake of both Cd and DEHP from co-contaminated soils; the maximum reduction of Cd (92.7%) and DEHP (52.0%) was observed in 2% pig biochar-treated LOC soil. The responses of plant physiological parameters to increased biochar applications indicated that less Cd and DEHP were taken up by plants. Pig biochar was more effective (P < 0.05) at reducing the bioavailability of Cd and DEHP in both soils than P. orientalis biochar; therefore, pig biochar had greater potential for improving the quality of the crop. However, the highest application rate (4%) of pig biochar restricted plant seed germination. Key factors influencing the bioavailability of Cd and DEHP in soils were soil organic carbon content, biochar properties (such as surface alkalinity, available phosphorus content and ash content) and biochar application rates. Unlabelled Image • 2% pig biochar significantly reduced Cd and DEHP uptake by plant. • Pig biochar was more effective in immobilizing pollutants than P. orientalis biochar. • Soil organic matter influenced greatly on biochar application. • 4% pig biochar dosage restricted seed germination. [ABSTRACT FROM AUTHOR]

Abstract Biochar produced from pyrolysis of biomass is a candidate with great potential for climate change mitigation by carbon sequestration and reduction of greenhouse gases (GHG) emission in soil. Its potential depends considerably on biochar properties. Biochar stability or biochar C recalcitrance is decisive to its carbon storage/sequestration potential in soil. Three groups of methods including: I) biochar C structure or composition analyses, II) biochar oxidation resistance determination, and III) biochar persistence assessment by incubation & modelling, have been developed for evaluation of biochar stability. Amongst, incubation & modelling is the most commonly used one and is the basis of the other two assessment methods. However, the strategies for incubation experiment designing and data modelling significantly influence the biochar stability results. Drastic differences were observed for stability results obtained from different studies partly because of the large flexibility of the incubation & modelling method. Biased biochar stability would be obtained if the method was used improperly. The present review aims to provide comprehensive information on method strategies used for incubation and modelling, followed by discussions on the key issues such as what kind of biochar to use, how the experiment should be designed, how to determine biochar C mineralization, how the mineralization data should be expressed, and what model should be used, for an accurate biochar stability evaluation. In general, incubating biochar at long-term duration, modelling incubation data with double-exponential model, using C isotopic technology for CO 2 evolution determination with C mineralization data express as percentage of total organic carbon mineralized, applying biochar in the field are favorable to biochar stability assessment. Other strategies such as the use of standard (reference) biochar materials may be effective to improve the assessment. Graphical abstract Unlabelled Image Highlights • The incubation method has many drawbacks and is slow. • C isotope is preferable to quantitate the biochar C mineralization. • Two-pool model with data expressed as % TOC mineralized is preferable. • Reference standard biochar can facilitate comparison between studies. [ABSTRACT FROM AUTHOR]