北京师范大学环境学院孙可教授团队利用连续化学萃取法和薄膜扩散梯度法(DGT),结合植物吸收状况,评估了植物和养殖废弃物制备的水热炭和裂解炭对土壤Cd的生物有效性的影响。相关成果发表于Science of The Total Environment(IF=4.610)。
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·Both plant- and manure-based hydrochar had low sorption efficacy for Cd in soils.
·Manure-based 450 °C pyrochar was most effective in reducing Cd bioavailability.
·DGT technique well reflected biochar's effect on Cd phytoavailability in the soil.
Biochar has emerged as a useful tool to reduce the bioavailability of heavy metals in contaminated soils. However, limited research has been directed towards determining the effects of pyrolysis conditions and feedstock types of biochar on the bioavailability of heavy metals in biochar-treated soils. This work evaluated the efficacy of plant- and manure-derived hydrochar and pyrochar for alleviating Cd bioavailability in soils using conventional chemical extraction, diffusive gradients in thin films (DGT) and plant uptake. For each feedstock type, hydrochar showed lower maximum adsorption capacity than pyrochar. As determined by diethylenetriamine pentaacetic acid, BCR extraction and DGT measurement, pyrochar significantly decreased the theoretical bioavailability of Cd. Moreover, a slight decrease in the ability of soil to resupply Cd to the solution was detected. Also, pyrochar induced a substantial reduction in Cd uptake in ryegrass. Corresponding to the high sorption capacity, swine solid-derived 450 °C pyrochar was most effective in alleviating Cd bioavailability in soils, indicating its great potential for remediating Cd-contaminated soils. Additionally, the bioavailable Cd amount determined by DGT had the best correlation with the Cd content in ryegrass, showing that DGT technology could better represent the effects of biochars on Cd phytoavailability in the studied soil.
生物炭已成为降低污染土壤中重金属生物有效性的有效手段。然而,对于热解条件和生物炭原料类型对生物炭处理土壤中重金属生物有效性的影响的研究还较少。本研究利用连续化学萃取法和薄膜扩散梯度法(DGT),结合植物吸收状况,评估了植物和养殖废弃物制备的水热炭和裂解炭对土壤Cd的生物有效性的影响。不同原料类型的水热炭的最大吸附能力均低于裂解炭。通过二乙三胺五乙酸、BCR萃取及DGT测定,可以确定裂解炭能够显著降低Cd的理论生物有效性,并检测到土壤向溶液中补充Cd的能力略有下降。此外,裂解炭能够显著降低黑麦草对Cd的吸收。猪养殖固体废弃物 在450°C下制备的裂解炭具有高吸附能力,在减轻土壤Cd生物有效性方面最有效,表明它具有修复Cd污染土壤的巨大潜力。此外,DGT测定的生物可利用Cd含量与黑麦草中Cd含量的相关性最强,表明DGT技术能更好地测定生物炭对土壤中Cd植物有效性的影响。
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