中文关键词凹凸棒石土壤钝化修复络合吸附硅羟基羧基 英文关键词attapulgitesoilpassivation remediationcomplexation adsorptionsilanol groupcarboxyl group

作者	单位	E-mail
陈展祥	中南林业科技大学环境科学与工程学院, 长沙 410004 中国科学院生态环境研究中心城市与区域生态国家重点实验室, 北京 100085	chenzhanxiang@163.com
陈传胜	中南林业科技大学环境科学与工程学院, 长沙 410004
陈卫平	中国科学院生态环境研究中心城市与区域生态国家重点实验室, 北京 100085
焦文涛	中国科学院生态环境研究中心城市与区域生态国家重点实验室, 北京 100085	wtjiao@rcees.ac.cn

中文摘要 采用室内盆栽实验和吸附平衡实验，研究了凹凸棒石及其改性材料对土壤镉移动性和生菜吸收镉的影响，并通过X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）以及X射线光电子能谱（XPS）探讨了其机制.结果表明，凹凸棒石及其改性材料均可显著降低生菜体内的Cd含量，改性材料作用优于未改性材料，分别使生菜地上部分Cd含量最大降低41.0%和56.5%.凹凸棒石及其改性材料在投加量为1%时均可显著降低土壤CaCl₂提取态Cd含量，最大降低幅度分别为34.2%和34.3%.凹凸棒石改性后对镉的饱和吸附容量明显提高.凹凸棒石主要是通过表面的硅羟基与Cd²⁺发生配位反应形成络合物来固定土壤镉，而改性凹凸棒石材料能够通过其表面的硅羟基和羧基与Cd²⁺发生配位反应形成络合物，从而降低Cd²⁺在土壤中的移动性，进而达到钝化修复Cd污染土壤的效果.因此凹凸棒石及其改性材料均可被用于镉污染农田土壤修复，但机制不同. 英文摘要 The effect of attapulgite (magnesium aluminium phyllosilicate) and its modified materials on the extractability of soil Cd and the accumulation of Cd in lettuce (Lactuca sativa) were investigated using a pot-culture experiment, and the immobilization mechanism of attapulgite and its modified materials was explored through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that attapulgite and its modified materials could significantly reduce the Cd concentration in Lactuca sativa, with maximum reductions of 41.0% and 56.5%, respectively, and attapulgite modified materials treatments appeared more efficient than attapulgite treatments in reducing Cd uptake of Lactuca sativa. The saturated adsorption capacity for the adsorption of Cd²⁺ on attapulgite rose distinctly after being modified. Attapulgite and its modified materials could significantly reduce Cd content in soil CaCl₂ extract at the dosage of 1%, with the maximum reduction rates of 34.2% and 34.3%, respectively. The attapulgite formed a complex to immobilize Cd mainly through the surface silanol and Cd²⁺ complexation reaction, while the modified attapulgite formed a complex mainly through the complexation of Cd²⁺ with carboxyl groups which existed in addition to the complexation with surface hydroxyl, thus reducing the mobility of Cd²⁺ and achieving remediation of Cd-contaminated soil. In summary, attapulgite and its modified materials can both be used for remediation of Cd-contaminated soil, and the mechanisms for this function were found to be different.

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