Interaction with low molecular weight organic acids affects the electron shuttling of biochar for Cr(VI) reduction

Xu, Zibo; Xu, Xiaoyun; Tao, Xinyi; Yao, Chengbo; Tsang, Daniel C.W.; Cao, Xinde

doi:10.1016/j.jhazmat.2019.05.098

Cited by 111 publications

(40 citation statements)

References 52 publications

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“…Particles on the surface of biochars consisting of carbon‐coated minerals are particularly effective in reducing bioavailability of heavy metals (Kumar & Prasad, 2018). Incorporation into organo‐mineral microagglomerates can reduce Cr(VI) to Cr(III) through interaction with reduced Fe, organic compounds, and free radicals (Odinga et al, 2020), including through electron shuttling (Xu et al, 2019), reducing their availability to plants (Kumar, Joseph, et al, 2018; Kumar et al, 2020).…”

Section: Mechanisms Of Biochar Effects On Soil and Plantsmentioning

confidence: 99%

How biochar works, and when it doesn't: A review of mechanisms controlling soil and plant responses to biochar

et al. 2021

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We synthesized 20 years of research to explain the interrelated processes that determine soil and plant responses to biochar. The properties of biochar and its effects within agricultural ecosystems largely depend on feedstock and pyrolysis conditions. We describe three stages of reactions of biochar in soil: dissolution (1–3 weeks); reactive surface development (1–6 months); and aging (beyond 6 months). As biochar ages, it is incorporated into soil aggregates, protecting the biochar carbon and promoting the stabilization of rhizodeposits and microbial products. Biochar carbon persists in soil for hundreds to thousands of years. By increasing pH, porosity, and water availability, biochars can create favorable conditions for root development and microbial functions. Biochars can catalyze biotic and abiotic reactions, particularly in the rhizosphere, that increase nutrient supply and uptake by plants, reduce phytotoxins, stimulate plant development, and increase resilience to disease and environmental stressors. Meta‐analyses found that, on average, biochars increase P availability by a factor of 4.6; decrease plant tissue concentration of heavy metals by 17%–39%; build soil organic carbon through negative priming by 3.8% (range −21% to +20%); and reduce non‐CO2 greenhouse gas emissions from soil by 12%–50%. Meta‐analyses show average crop yield increases of 10%–42% with biochar addition, with greatest increases in low‐nutrient P‐sorbing acidic soils (common in the tropics), and in sandy soils in drylands due to increase in nutrient retention and water holding capacity. Studies report a wide range of plant responses to biochars due to the diversity of biochars and contexts in which biochars have been applied. Crop yields increase strongly if site‐specific soil constraints and nutrient and water limitations are mitigated by appropriate biochar formulations. Biochars can be tailored to address site constraints through feedstock selection, by modifying pyrolysis conditions, through pre‐ or post‐production treatments, or co‐application with organic or mineral fertilizers. We demonstrate how, when used wisely, biochar mitigates climate change and supports food security and the circular economy.

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Section: Mechanisms Of Biochar Effects On Soil and Plantsmentioning

confidence: 99%

How biochar works, and when it doesn't: A review of mechanisms controlling soil and plant responses to biochar

et al. 2021

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“…The interaction mechanism between biochar and Cr is mainly manifested in the surface adsorption effect of Cr(Ⅵ) by the oxygen-containing functional groups such as C-O, C=O, -COOH and -OH in biochar, as well as the reduction reaction of electrons provided by biochar [ 105 ]. Specifically, biochar transforms Cr(Ⅵ) into Cr(Ⅲ) with lower toxicity and solubility by adsorption–reduction effects, and participates in the formation of Cr 2 O 3 and/or Cr(OH) 3 precipitation, so as to achieve the purpose of Cr immobilization [ 109 , 110 ]. On the other hand, Choppala et al [ 27 ] applied chicken-manure-derived biochar to Cr-spiked soil with low organic matter content, which significantly increased the supply of soil organic carbon and nutrients, enhancing the soil respiration and microbial activity effectively and finally showing a superior microbial Cr(Ⅵ) reduction effect and reduced the Cr biotoxicity.…”

Section: Remediation Of Soil Hms Contamination By Biocharmentioning

confidence: 99%

Application Research of Biochar for the Remediation of Soil Heavy Metals Contamination: A Review

Cheng

Chen

Xu³

et al. 2020

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Soil contamination by heavy metals threatens the quality of agricultural products and human health, so it is necessary to choose certain economic and effective remediation techniques to control the continuous deterioration of land quality. This paper is intended to present an overview on the application of biochar as an addition to the remediation of heavy-metal-contaminated soil, in terms of its preparation technologies and performance characteristics, remediation mechanisms and effects, and impacts on heavy metal bioavailability. Biochar is a carbon-neutral or carbon-negative product produced by the thermochemical transformation of plant- and animal-based biomass. Biochar shows numerous advantages in increasing soil pH value and organic carbon content, improving soil water-holding capacity, reducing the available fraction of heavy metals, increasing agricultural crop yield and inhibiting the uptake and accumulation of heavy metals. Different conditions, such as biomass type, pyrolysis temperature, heating rate and residence time are the pivotal factors governing the performance characteristics of biochar. Affected by the pH value and dissolved organic carbon and ash content of biochar, the interaction mechanisms between biochar and heavy metals mainly includes complexation, reduction, cation exchange, electrostatic attraction and precipitation. Finally, the potential risks of in-situ remediation strategy of biochar are expounded upon, which provides the directions for future research to ensure the safe production and sustainable utilization of biochar.

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“…Several studies demonstrated that the electrotrophs gene expression is not similar to exoelectrogens such as omcZ genes and pilA. However, in case of G. sulfurreducens which reduced the Cr +4 to Cr +3 , mean toxic state to insoluble state through accepting the electrons [145]. The basic operational concept is based on the biological conversions at the surface of the anode which are used to transfer the electrons and drive reductive precipitation of metal ions.…”

Section: Mechanism Of Electricity Generation and Pollutant Removal In Mfcsmentioning

confidence: 99%

Outlook on the Role of Microbial Fuel Cells in Remediation of Environmental Pollutants with Electricity Generation

et al. 2020

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A wide variety of pollutants are discharged into water bodies like lakes, rivers, canal, etc. due to the growing world population, industrial development, depletion of water resources, improper disposal of agricultural and native wastes. Water pollution is becoming a severe problem for the whole world from small villages to big cities. The toxic metals and organic dyes pollutants are considered as significant contaminants that cause severe hazards to human beings and aquatic life. The microbial fuel cell (MFC) is the most promising, eco-friendly, and emerging technique. In this technique, microorganisms play an important role in bioremediation of water pollutants simultaneously generating an electric current. In this review, a new approach based on microbial fuel cells for bioremediation of organic dyes and toxic metals has been summarized. This technique offers an alternative with great potential in the field of wastewater treatment. Finally, their applications are discussed to explore the research gaps for future research direction. From a literature survey of more than 170 recent papers, it is evident that MFCs have demonstrated outstanding removal capabilities for various pollutants.

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Interaction with low molecular weight organic acids affects the electron shuttling of biochar for Cr(VI) reduction

Cited by 111 publications

References 52 publications

How biochar works, and when it doesn't: A review of mechanisms controlling soil and plant responses to biochar

How biochar works, and when it doesn't: A review of mechanisms controlling soil and plant responses to biochar

Application Research of Biochar for the Remediation of Soil Heavy Metals Contamination: A Review

Outlook on the Role of Microbial Fuel Cells in Remediation of Environmental Pollutants with Electricity Generation

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