Biochar最新文献

Numerous studies have unequivocally demonstrated that biochar and, to a lesser degree, earthworms can independently improve soil fertility and crop productivity, although information about their co-application effects on soil characteristics is limited. In this review, (1) earthworm biomarkers and underlying influencing factors, as well as the changes in the amended soil quality in response to co-application of earthworms and biochar are presented, (2) the functional interactions between earthworms and biochar in soil are summarized; (3) the principles governing the synergetic effects of biochar and earthworms on soil quality enhancement are probed; and (4) alternative strategies to optimize the efficacy of earthworm and biochar amendments are provided. It is noteworthy that while low doses of biochar can have a positive effect on various earthworm biomarkers, including growth and reproduction, restoration of the intestinal environment, and the mitigation of cellular organelle toxicity and genetic damage, high biochar dosages can yield adverse effects. Conversely, earthworms play a crucial role in distributing biochar particles deeper into the soil matrix, bolstering carbon sequestration potential, and enhancing the persistence and efficiency of biochar utilization. Moreover, earthworms stimulate the production of soil extracellular enzymes by microorganisms, which are pivotal to the processing, stabilization, and decomposition of soil organic matter, as well as nutrient cycling in terrestrial ecosystems. Additionally, they enhance the binding affinities of these enzymes to biochar. Significantly, changes in earthworm biomarkers in response to biochar integration are predominately governed by biochar properties and dosage, contact time, and soil type.

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The extensive use of neonicotinoids on food crops for pest management has resulted in substantial environmental contamination. It is imperative to develop an effective remediation material and technique as well as to determine the evolution pathways of products. Here, novel ball-milled nitrogen-doped biochar (NBC)-modified zero-valent iron (ZVI) composites (named MNBC-ZVI) were fabricated and applied to degrading neonicotinoids. Based on the characterization results, NBC incorporation introduced N-doped sites and new allying heterojunctions and achieved surface charge redistribution, rapid electron transfer, and higher hydrophobicity of ZVI particles. As a result, the interaction between ZVI particles and thiamethoxam (a typical neonicotinoid) was improved, and the adsorption–desorption and reductive degradation of thiamethoxam and ·H generation steps were optimized. MNBC-ZVI could rapidly degrade 100% of 10 mg·L⁻¹ thiamethoxam within 360 min, its reduction rate constant was 12.1-fold greater than that of pristine ZVI, and the electron efficiency increased from 29.7% to 57.8%. This improved reactivity and selectivity resulted from increased electron transfer, enhanced hydrophobicity, and reduced accumulation of iron mud. Moreover, the degradation of neonicotinoids occurred mainly via nitrate reduction and dichlorination, and toxicity tests with degradation intermediates revealed that neonicotinoids undergo rapid detoxification. Remarkably, MNBC-ZVI also presented favorable tolerance to various anions, humic acid, wastewater and contaminated soil, as well as high reusability. This work offers an efficient and economic biochar-ZVI remediation technology for the rapid degradation and detoxification of neonicotinoids, significantly contributes to knowledge on the relevant removal mechanism and further advances the synthesis of highly reactive and environmentally friendly materials.

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Biochar has gained significant attention in agricultural and environmental research over the last two decades. This comprehensive review evaluates the effects of biochar on soil organic carbon (SOC), emission of non-CO₂ greenhouse gases, and crop yield, including related mechanisms and major influencing factors. The impacts of biochar on SOC, methane and nitrous oxide emissions, and crop yield are controlled by biochar and soil properties and management practices. High-temperature biochar produced from lignin-rich feedstocks may decrease methane and nitrous oxide emissions in acidic soils and strengthen long-term carbon sequestration due to its stable aromatic structure. In contrast, low-temperature biochar from manure may increase crop yield in low-fertility soils. Applying biochar to farmlands in China can increase SOC content by 1.9 Pg C and reduce methane and nitrous oxide emissions by 25 and 20 Mt CO₂-eq year⁻¹, respectively, while increasing crop yields by 19%. Despite the increasing evidence of the positive effects of biochar, future research needs to explore the potential factors that could weaken or hinder its capacity to address climate change and secure crop production. We conclude that biochar is not a universal solution for global cropland; however, targeted applications in fields, landscapes, or regional scales, especially in low fertility and sandy soils, could realize the benefits of biochar as a climate-smart measure.

Highlights

• The findings of research on biochar's effects on soil C sequestration, GHG mitigation, and crop production were summarized.

• The factors influencing the impact of biochar on soil functioning were reviewed.

• The effects of biochar on soil C sequestration and GHG mitigation in farmlands of China were quantified.

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Biochar, as a potential CO₂ adsorbent, is of great significance in addressing the problem of global warming. Previous studies have demonstrated that the CO₂ adsorption performance of biochar can be improved by nitrogen and sulfur doping. Co-doping can integrate the structure and function of two elements. However, the physicochemical interaction of nitrogen and sulfur during doping and the CO₂ adsorption process remains unclear in co-doped biochar. In this study, the heteroatom-doped biochar was prepared with different additives (urea, sodium thiosulfate, and thiourea) via hydrothermal carbonization, and the physicochemical interaction of nitrogen and sulfur in co-doped biochar was investigated extensively. The findings revealed that nitrogen and sulfur competed for limited doped active sites on the carbon skeleton during the co-doping process. Interestingly, thiourea retained the amino group on the surface of biochar to a great extent due to carbon–sulfur double bond breaking and bonding, which facilitated the formation of pore in the activation process. Significantly, co-doping had no significant improvement effect although nitrogen and sulfur doping separately enhanced the CO₂ adsorption performance of biochar by 11.9% and 8.5%. The nitrogen-containing and sulfur-containing functional groups in co-doped biochar exhibited mutual inhibition in the process of CO₂ adsorption. The findings of this study will have pertinent implications in the application of N/S co-doped biochar for CO₂ adsorption.

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Biochar wettability and ability to accumulate moisture inside the porous space are crucial for improving soil fertility, regulating soil water balance, and regulating nutrients. However, a long-term interaction of biochar with agricultural soils may drastically alter the wetting properties and, eventually, influence water holding capacity and the structure of soils. In this work, the structure and wetting properties of biochar samples after 6-year long exposure to a sandy loam Spodosol with a crop rotation and mineral fertilizers application were studied. It was found that the elemental composition of the aged biochars was richer and more "soil-like", which is explained by the presence of the mineral crust on the biochar surface. The temporal evolution of biochar in the soil without any mineral fertilizer application resulted in significant improvement of its surface wettability due to the effects of various environmental factors. The lateral surface of biochar after 6-year interaction with the soil changes into a loose porous layer in a form of grooved base filled with adherent mineral soil and clay particles. Contrary, the application of the mineral fertilizer to the soil resulted in decreased wettability of the biochar lateral surfaces due to a decrease in the polar component of surface energy and the crusting of the surface with fine material, which blocks the pore space of the biochar. As a result, water capacity of the biochar from the treatment with the fertilizer decreased compared to the biochar samples collected from the soil without the fertilizer application. The radial biochar surfaces of both types of samples collected from the soil were open vessels filled with soil particles that slow down complete wetting and water absorption. The treatment of the biochar samples with surfactants drastically increased wettability of lateral surface and water absorption capacity of control samples as compared to the samples collected from the soil. The obtained results support the idea that the hydrophilisation of biochar caused by the adhesion of soil particles and treatment of its pore surface with surfactants, can improve the water-holding capacity of the sandy loam Spodosol in the plant-available range of soil water.

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Icing of wind turbine blades will seriously hinder the development of the wind power industry, and the use of biomass resources to solve the icing problem is conducive to promoting the synergistic development of biomass and wind energy. In this study, ice-phobic coatings with photothermal and anti-corrosion properties were prepared by surface modification pyrolysis and hydrothermal reaction with rice straw biogas residue as raw material. The erosion of KOH and the surface modification of MoS₂ produced a rough structure of the material, and the high-temperature pyrolysis and hydrothermal reaction promoted the dehydrogenation and decarboxylation reactions, which reduced the number of oxygen-containing functional groups and decreased the surface energy of the material. The ice-phobic coating has superhydrophobic properties with a contact angle of 158.32°. Due to the small surface area in contact with water, the coating was able to significantly reduce the icing adhesion strength to 53.23 kPa. The icing wind tunnel test results showed that the icing area and mass were reduced by 10.54% and 30.08%, respectively, when the wind speed was 10 m s⁻¹ and the temperature was − 10 °C. Photothermal performance tests showed that the MoS₂-loaded material had light absorption properties, and the coating could rapidly warm up to 58.3 ℃ under xenon lamp irradiation with photothermal cycle stability. The loading of MoS₂ acts as a physical barrier, reducing the contact of corrosive media with the substrate, thus improving the anti-corrosion of the coating. This study has practical application value and significance for the development of the anti-icing field under complex environmental conditions.

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