Application of biochars in the remediation of chromium contamination: Fabrication, mechanisms, and interfering species

Zheng, Chujing; Yang, Zhihui; Si, Mengying; Zhu, Feng; Yang, Weichun; Zhao, Feiping; Shi, Yan

doi:10.1016/j.jhazmat.2020.124376

Cited by 115 publications

(27 citation statements)

References 239 publications

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“…Studies showing significant reduction in bioavailability of heavy metals have often applied high rates of biochar, in excess of 10 Mg ha −1 (Chen et al, 2018; Wang et al, 2020). The surface O‐functional groups on biochar can immobilize heavy metals through ion exchange, precipitation, cation and anion metal attraction, reduction, electron shuttling, and physisorption (Figure 2; Ahmad et al, 2014; Ding et al, 2014; Liu, Xu, et al, 2018; Tan et al, 2015; Zheng et al, 2020). Alkalinity from biochar (the liming effect) increases pH of acid soils, increasing the negatively charged exchange sites on clay particles, attracting cationic metals (Figure 1).…”

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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“…Biochars are efficient for use in wastewater treatment, primarily due to their highly porous structure and their numerous chemical functionalities [1][2][3][4]. In wastewater treatment processes, adsorption is preferred due to characteristics of low implementation costs, relative operation simplicity, and minimal generation of by-products [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Process Parameters Optimization, Characterization, and Application of KOH-Activated Norway Spruce Bark Graphitic Biochars for Efficient Azo Dye Adsorption

et al. 2022

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In this work, Norway spruce bark was used as a precursor to prepare activated biochars (BCs) via chemical activation with potassium hydroxide (KOH) as a chemical activator. A Box–Behnken design (BBD) was conducted to evaluate and identify the optimal conditions to reach high specific surface area and high mass yield of BC samples. The studied BC preparation parameters and their levels were as follows: pyrolysis temperature (700, 800, and 900 °C), holding time (1, 2, and 3 h), and ratio of the biomass: chemical activator of 1: 1, 1.5, and 2. The planned BBD yielded BC with extremely high SSA values, up to 2209 m2·g−1. In addition, the BCs were physiochemically characterized, and the results indicated that the BCs exhibited disordered carbon structures and presented a high quantity of O-bearing functional groups on their surfaces, which might improve their adsorption performance towards organic pollutant removal. The BC with the highest SSA value was then employed as an adsorbent to remove Evans blue dye (EB) and colorful effluents. The kinetic study followed a general-order (GO) model, as the most suitable model to describe the experimental data, while the Redlich–Peterson model fitted the equilibrium data better. The EB adsorption capacity was 396.1 mg·g−1. The employment of the BC in the treatment of synthetic effluents, with several dyes and other organic and inorganic compounds, returned a high percentage of removal degree up to 87.7%. Desorption and cyclability tests showed that the biochar can be efficiently regenerated, maintaining an adsorption capacity of 75% after 4 adsorption–desorption cycles. The results of this work pointed out that Norway spruce bark indeed is a promising precursor for producing biochars with very promising properties.

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“…Before the secondary development and utilization of contaminated land, it must be fully restored and treated in order to prevent toxic soil from becoming a potential and lasting environmental hazard. Control measures for PTE pollution in soil include physical measures [46,47], chemical measures [48,49], agricultural measures [50,51], biological measures [52,53], and remediation using a combination of several measures [54]. According to the evaluation of the status of PTE pollution, it can be seen that there is serious Hg pollution in the study area.…”

Section: Soil Pte Pollution Remediation Measuresmentioning

confidence: 99%

Sources of and Control Measures for PTE Pollution in Soil at the Urban Fringe in Weinan, China

Han

Chen

Liu

et al. 2021

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The environment of the urban fringe is complex and frangible. With the acceleration of industrialization and urbanization, the urban fringe has become the primary space for urban expansion, and the intense human activities create a high risk of potentially toxic element (PTE) pollution in the soil. In this study, 138 surface soil samples were collected from a region undergoing rapid urbanization and construction—Weinan, China. Concentrations of As, Pb, Cr, Cu, and Ni (Inductively Coupled Plasma Mass Spectrometry, ICP-MS) and Hg (Atomic Fluorescence Spectrometry, AFS) were measured. The Kriging interpolation method was used to create a visualization of the spatial distribution characteristics and to analyze the pollution sources of PTEs in the soil. The pollution status of PTEs in the soil was evaluated using the national environmental quality standards for soils in different types of land use. The results show that the content range of As fluctuated a small amount and the coefficient of variation is small and mainly comes from natural soil formation. The content of Cr, Cu, and Ni around the automobile repair factory, the prefabrication factory, and the building material factory increased due to the deposition of wear particles in the soil. A total of 13.99% of the land in the study area had Hg pollution, which was mainly distributed on category 1 development land and farmland. Chemical plants were the main pollution sources. The study area should strictly control the industrial pollution emissions, regulate the agricultural production, adjust the land use planning, and reduce the impact of pollution on human beings. Furthermore, we make targeted remediation suggestions for each specific land use type. These results are of theoretical significance, will be of practical value for the control of PTEs in soil, and will provide ecological environmental protection in the urban fringe throughout the urbanization process.

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Application of biochars in the remediation of chromium contamination: Fabrication, mechanisms, and interfering species

Cited by 115 publications

References 239 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

Process Parameters Optimization, Characterization, and Application of KOH-Activated Norway Spruce Bark Graphitic Biochars for Efficient Azo Dye Adsorption

Sources of and Control Measures for PTE Pollution in Soil at the Urban Fringe in Weinan, China

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