Comprehensive insight into the transformation mechanism of Cd fractionation in the components of paddy soils under cysteine leaching

文献类型： 外文期刊

第一作者： Li, Kewei

作者： Li, Kewei;Jiang, Luhua;Sarkodie, Emmanuel Konadu;Guo, Ziwen;Yang, Jiejie;Shi, Jiaxin;Peng, Yulong;Liu, Hongwei;Liu, Xueduan;Deng, Yan;Jiang, Huidan;Li, Kewei;Jiang, Guomin;Liu, Yongfeng;Dong, Fen

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关键词： Cd contamination; Paddy soil; Soil leaching; Cysteine; Transformation mechanism

期刊名称：JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING （ 影响因子：7.7； 五年影响因子：7.3 ）

ISSN： 2213-2929

年卷期： 2024 年 12 卷 3 期

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收录情况： SCI

摘要： Cadmium (Cd) contamination in paddy soils poses a serious threat to agricultural production and human health. In this study, cysteine was selected as the leaching agent for remediating Cd-contaminated paddy soils because of its effective, low cost and ecofriendly characteristics. Microcosmic simulation experiment was using to investigate the fate of Cd and elucidate the transformation mechanism of Cd in the key components of paddy soil under cysteine leaching. Results showed that the total Cd removal rate of paddy soils reached 46.8-87.4% under the optimal conditions. This was mainly attributed to the decrease of exchangeable fraction (F1), carbonate bound fraction (F2), iron/manganese-bound fraction (F3) and organic matter bound fraction (F4) of Cd. After cysteine leaching, soil fertility was promoted due to the increase in nitrate nitrogen (NN), ammonia nitrogen (AN), available phosphorus (AP) and organic matter (OM). pH, CaCO3, available potassium (AK), NN, AP, amorphous iron oxides (Feo) were the main contributors to Cd fractionation transformation. The desorption of Cd from ferrihydrite (Fh) and goethite (Gt) surfaces is hypothesized to stem from dual mechanisms: the dissolution due to the low solution pH and the reducibility of cysteine, which facilitated the conversion of Fh and Gt to hematite (Hm). And the -SH complexation also ascribed to the activation of Cd bound by Fe-OH in Fh and Gt and oxygencontaining functional groups in humic acid (Ha). For chlorite (Ch), the primary driver for Cd desorption was identified as an ion-exchange process, whereby electrostatically adsorbed Cd2+ were replaced by H+ produced by cysteine protonation.

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