Biochar has been proposed as a soil amendment in vegetable fields, where the widespread use of plastic film leads to significant retention of microplastics (MPs) in the soil. However, the interactive effect of biochar and MPs on plant growth and soil functions remains poorly understood. Here, we conducted a pot experiment to examine the effects of biochar application in the presence of conventional and biodegradable microplastics (0.05% w/w) on the growth of coriander, soil nitrogen (N) cycling processes, and microbial communities. The results showed that biochar application increased aboveground biomass by increasing plant available N of NH4+, regardless of the presence of MPs. Biochar also significantly reduced soil nitrous oxide (N2O) emissions by an average of 16% without MPs. However, when MPs were present, the effect of biochar on N2O emissions was lessened depending on the MP type. Polylactic acid consistently reduced soil N2O emissions and the abundance of N2O production genes, irrespective of biochar application. Conversely, polyethylene without biochar reduced N2O emissions primarily by inhibiting N-related functional genes responsible for nitrification and denitrification. This inhibitory effect was reversed when biochar was applied, leading to a 26% increase in N2O emissions due to increased nifH and nirK gene abundance. Although biochar and MPs did not significantly alter microbial α-diversity, they altered the composition and structure of bacterial and fungal communities, linked to changes in soil N turnover. Our study underscores the critical role of MP type in assessing the effects of biochar on soil N cycling and N2O emissions. Consequently, plastic pollution may complicate the ability of biochar to improve plant growth and soil functions, depending on the characteristics of the MPs.Graphical

The increased contamination of potentially toxic element (PTE) has posed remarkable ecological risks to environment. Application of functionalized biochar for the remediation of PTE contaminated water and soils are of great concern, and effective strategies are urgently needed to enhance the removal capacity of biochar for PTE. As a novel surface modification technology, the effect of layered double hydroxides (LDH) and sodium dodecyl sulfonate (SDS) on the remediation capacity of biochar for PTE polluted soils and water remains unclear. Sawdust biochar (SB) was coated with Mg and Fe to synthesize the Mg-Fe-LDH functionalized biochar (MFB); thereafter, the MFB was mixed with SDS solution to synthesize the organic-Mg-Fe-LDH biochar (MSB). The potential of SB, MFB, and MSB for remediation of Cd and Pb contaminated soil and water was evaluated in terms of adsorption capacity, immobilization efficiency, and stability. Loading of Mg-Fe-LDH into SB, along with SDS treatment created a regular micro-nano hierarchical structure and enhanced the surface roughness, aromaticity, and hydrophobicity of MSB as compared to SB. MSB exhibited a significantly higher maximum adsorption capacity (mg g−1) for water Pb (405.2) and Cd (673.0) than MFB (335.9 for Pb and 209.0 for Cd) and SB (178.2 for Pb and 186.1 for Cd). MSB altered the soluble fraction of Cd/Pb to the residual fraction and thus significantly decreased their mobilization in soil. The higher removal/immobilization efficiency of MSB could be attributed to its alkalinity, and the enhanced synergistic interactions including surface precipitation, ion exchange, complexation, and hydrogen bonding. The resistance to carbon loss by H2O2, thermal recalcitrance index R50, and degree of graphitization in MSB were significantly improved compared to SB, indicating a more stable carbon fraction sequestered in MSB following aging in soil. These results indicate that MSB could be used for remediation of Cd and Pb contaminated soil and water.Graphical

This study aimed to enhance the economic viability and sustainability of the cotton industry by converting cottonseed into energy. Cottonseed was subjected to lipid extraction for biodiesel production, and a pyrolysis test was conducted under N2 and CO2 conditions to valorise defatted cottonseed. Under CO2 conditions, the increase in CO concentration was due to homogeneous reaction of CO2 with volatile matters. Biochar, a pyrolytic product of defatted cottonseed, was used as a catalyst for thermally induced transesterification, and showed high performance in biodiesel conversion efficiency due to its abundant alkaline earth metals and meso-/macro-pores. For example, transesterification using silica at 250 ˚C yielded only 1.6 wt.% biodiesel, whereas using biochar at the same temperature resulted in a significantly higher biodiesel yield of 83.5 wt.%. This study experimentally proved that 7,900 tons (304 million MJ) of biodiesel could be produced annually, surpassing the diesel fuel requirement (145 million MJ) for cotton cultivation. These results indicate the potential to fully replace fossil fuels in the cotton industry.Graphical

The draining and conversion of peatlands for agriculture has led to their degradation globally, diminishing their carbon (C) storage capacity and functioning. However, rewetting, alongside the addition of organic/inorganic amendments, has the potential to accelerate peat formation and C accrual. The aim of this experiment was therefore to examine the combined benefits of altering water table depth and adding organic (e.g., biochar, paper waste, biosolids, cereal straw; 20 t C ha−1) and inorganic (e.g., FeSO4; 0.5 t ha−1) materials on net C storage and peatland functioning (i.e., microbial communities, greenhouse gas emissions and biogeochemical cycling). The experiment consisted of outdoor agricultural peat mesocosms monitored over 1 year. The relative effectiveness of the amendments in preserving peat-C (t C ha−1) followed the series: Miscanthus biochar (18.9 t C ha−1) > Miscanthus residues (17.3 t C ha−1) > biosolids (17.2 t C ha−1) > cereal straw (14.5 t C ha−1) > paper waste (13.3 t C ha−1) based on C additional rate (20 t C ha−1). Overall, a high-water table combined with biochar and FeSO4 addition was the most effective at suppressing enzyme activity (e.g., β-glucosidase, phenol oxidase, cellobiase), methanogen activity (e.g., Methanosarcina) and peat mineralization rate. We ascribe this in part to changes in the fungal and bacterial community structure (e.g., reductions in Actinobacteria by − 22% and Ascomycota by − 61%). FeSO4 also increased the Fe-bound C content in the non-rewetted treatment, supporting the ‘iron gate’ mechanism for C preservation. The mechanisms behind our results appear to be both abiotic (affecting SOC solubility through changes in redox conditions and Fe–C interactions) and biotic (via shifts in microbial community and enzyme activities), creating conditions that enhance C preservation. These findings provide evidence for implementing biochar and FeSO4 amendments alongside water table management as practical, scalable strategies for restoring C storage capacity in agricultural peatlands.Supplementary InformationThe online version contains supplementary material available at 10.1007/s42773-025-00501-y.

High conversion rate and selectivity are challenges for CO2 utilization through catalytic reverse water gas shift (RWGS) reaction. Herein, a novel mesoporous biochar (MB) supported Cu-Mo2C nano-interface was prepared by consecutive physical activation of coconut shells followed by carbothermal hydrogen reduction of bimetal. As compared with traditional carbon materials, this MB exhibited ultra-high specific surface area (2693 m2 g–1) and mesopore volume of mesopore (0.81 cm3 g–1) with a narrow distribution (2–5 nm), responsible for the high dispersion of binary Cu-Mo2C sites, CO2 adsorption and mass transfer in the reaction system. Moderate carbothermal reduction led to the sufficient reduction of Mo ion with carbon matrix of MB and dispersive growth of nano Cu-Mo2C binary sites (~ 6.1 nm) on the surface of MB. Cu+ species were formed from Cu0 via electron transfer and showed high dispersion with simultaneous boosted bimetal loading due to the strong interaction between nano Mo2C and Cu. These were advantageous to the intrinsic activity and stability of the Cu-Mo2C binary sites and their accessibility to the reactant molecules. Under the RWGS reaction conditions of 500 °C, atmospheric pressure, and 300,000 ml/g/h gas hour space velocity, the CO2 conversion rate over Cu-Mo2C/MB reached 27.74 × 10–5 molCO2/gcat/s at very low H2 partial pressure, which was more than twice that over traditional carbon supported Cu-Mo2C catalysts. In addition, this catalyst exhibited 99.08% CO selectivity and high stability for more than 50 h without a decrease in activity and selectivity. This study offers a new development strategy and a promising candidate for industrial RWGS.Graphical

Wastewater produced in beryllium mining seriously affects ecological balance and causes great environmental pressure. We designed a novel porous lotus leaf biochar modified with PO43−/NH4+ multifunctional groups (MLLB) and used it for beryllium(Be) removal from beryllium mining wastewater. Kinetic and thermodynamic experiments showed that the adsorption capacity (Qe) of Be with MLLB from the simulated beryllium mining wastewater could reach 40.38 g kg−1 (35 °C, pH = 5.5), and the adsorption process was spontaneous and endothermic. The dispersion coefficient Kd of Be with MLLB was 2.6 × 104 mL g−1, which proved that MLLB had strong selective adsorption capacity for Be. Phosphoric acid, ammonia, and hydroxyl groups on the MLLB surface would complex with Be to form Be(OH)2 and Be(NH4)PO4 complexation products, which implied that surface complexation and precipitation reactions might co-existed in the adsorption process. The above results showed that MLLB could effectively adsorb Be and prevent beryllium exposure in a beryllium mining process.Graphical

Abstract Reductive dissolution of barium (Ba) sulfate in wetland soils may increase Ba bioavailability in the environment, yet no information is available regarding Ba remediation using biochar. This study investigated the effectiveness of sugarcane (Saccharum officinarum) straw biochar pyrolyzed at 350 °C (BC350), 550 °C (BC550), and 750 °C (BC750) in inhibiting barite dissolution and, consequently, Ba availability in a soil artificially spiked with barite and flooded for 365 days. Increasing pyrolysis temperature alters the carbon structure, and increases dehydration and depolymerization, resulting in more stable biochar that releases less DOC (8.6-fold decrease from BC350 to BC750). Additionally, high-temperature biochar (BC750) had 1.7 times higher carbon (C) content, 2.4 times higher ash content, and a 13.1 times greater specific surface area (SSA) than low-temperature biochar (BC350). Amending soil with BC750 increased pH but did not promote reducing conditions, and thus did not promote barite dissolution. Conversely, greater DOC in low-temperature biochar, particularly BC350, favored reducing conditions and increased barite dissolution by 23%, with BC550 also showing an 18% increase. This enhancement led to a greater pool of Ba sorbed into more labile exchangeable sites. In summary, pyrolysis temperature affects biochar attributes, which in turn influences the soil geochemical environment and Ba speciation. Low-temperature biochar (BC350) shows potential as an amendment to increase the bioavailable Ba pool in assisted remediation programs, such as biochar-assisted phytoremediation. Graphical Abstract

Anaerobic digestion technology, effective for sustainable waste management and renewable energy, but challenged by slow reaction rates and low biogas yields, could benefit from advancements in magnetic nanomaterials. This review explores the potential of magnetic nanomaterials, particularly magnetic biochar nanocomposites, to address these challenges by serving as electron conduits and providing essential iron. This review contributes a thorough overview of the application of magnetic nanoparticles loaded into biochar in anaerobic digestion and engages in a comprehensive discussion regarding the synthesis methods and characterization of various magnetic nanoparticles, elucidating their mechanisms of action in both the absence and presence of magnetic fields. Our review underscores the predominance of co-precipitation (53%) and commercially sourced nanoparticles (29%) as the main synthesis methods, with chemical reduction, pyrolysis, and green synthesis pathways less commonly utilized (8%, 5%, and 5%, respectively). Notably, pyrolysis is predominantly employed for synthesizing magnetic biochar nanocomposites, reflecting its prevalence in 100% of cases for this specific application. By offering a critical evaluation of the current state of knowledge and discussing the challenges and future directions for research in this field, this review can help researchers and practitioners better understand the potential of magnetic biochar nanocomposites for enhancing anaerobic digestion performance and ultimately advancing sustainable waste management and renewable energy production.Graphical

The residue of atrazine in field soils poses a major threat to crop growth in the rotation system, raising concerns about grain security and food safety. Current agricultural production requires more efficient and cost-effective mitigation measures in response to the emerging threat. This study reported the critical concentration (0.1 mg L−1) of atrazine injury to soybean seedlings in soil pore water and how biochar amendment could influence the distribution of atrazine in different soil environments. The results showed that biochar significantly reduced the concentration of atrazine in soil pore water, for example, 0.5% biochar in red (cinnamon, fluvo-aquic, paddy, black) soil reduced atrazine concentration from 0.31 (0.20, 0.18, 0.12, 0.03) mg L−1 to 0.004 (0.002, 0.005, 0.013, 0.011) mg L−1 in pore water (P < 0.01). On the basis of these, a reliable mathematical model was developed to predict the atrazine concentration in soil pore water under (or without) biochar amendment conditions. The verification results showed that the mean absolute percentage error of the model was 14.1%, indicating that the prediction error was within a reasonable range. Our work provides a precise solution to crop injury caused by soil residual herbicides with the aid of biochar, which reduces the bioavailability of atrazine in soybean seedlings. This method not only maximizes the use of biochar but also provides effective crop protection and environmental benefits.Graphical

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