Enhanced heavy metal immobilization in soil by grinding with addition of nanometallic Ca/CaO dispersion mixture.
Enhanced heavy metal immobilization in soil by grinding with addition of nanometallic Ca/CaO dispersion mixture.
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DOI：
10.1016/j.chemosphere.2012.06.030
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发表时间：
2012-10
期刊：
影响因子：
8.8
通讯作者：
Srinivasa Reddy Mallampati;Y. Mitoma;T. Okuda;S. Sakita;Mitsunori Kakeda
中科院分区：
文献类型：
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作者：
Srinivasa Reddy Mallampati;Y. Mitoma;T. Okuda;S. Sakita;Mitsunori Kakeda
本研究研究了使用纳米金属 Ca 和 CaO 分散混合物固定污染土壤中的重金属（As、Cd、Cr 和 Pb）。简单研磨可实现 85-90% 的重金属固定化，但通过添加研磨产生的纳米金属 Ca/CaO 分散混合物，可以将其进一步提高至 98-100%。使用SEM-EDS元素图和半定量分析的观察表明，纳米金属Ca/CaO处理后，土壤颗粒表面可测量的As、Cd、Cr和Pb含量减少。纳米金属Ca/CaO处理后，可浸出重金属浓度降低至低于日本土壤淋洗标准规定阈值：As、Cd、Pb<0.01mgL−1； Cr 为 0.05mgL−1。土壤湿度和pH值对重金属固定化的影响并不强烈。纳米金属 Ca/CaO 处理增强重金属固定能力的最可能机制可能是由于重金属吸附和截留在新形成的团聚体中，从而促进土壤颗粒聚集并与 Ca/CaO 相关的固定盐封闭/结合。结果表明，纳米金属Ca/CaO混合物适用于正常湿度条件下重金属污染土壤的固定化。
This study investigated the use of a nanometallic Ca and CaO dispersion mixture for the immobilization of heavy metals (As, Cd, Cr and Pb) in contaminated soil. Simple grinding achieved 85–90% heavy metal immobilization, but it can be enhanced further to 98–100% by addition of a nanometallic Ca/CaO dispersion mixture produced by grinding. Observations using SEM-EDS elemental maps and semi-quantitative analysis showed that the amounts of As, Cd, Cr, and Pb measurable on the soil particle surface decrease after nanometallic Ca/CaO treatment. The leachable heavy metal concentrations were reduced after nanometallic Ca/CaO treatment to concentrations lower than the Japan soil elution standard regulatory threshold: <0.01mgL−1for As, Cd, and Pb; and 0.05mgL−1for Cr. Effects of soil moisture and pH on heavy metal immobilization were not strongly influenced. The most probable mechanisms for the enhancement of heavy metal immobilization capacity with nanometallic Ca/CaO treatment might be due to adsorption and entrapment of heavy metals into newly formed aggregates, thereby prompting aggregation of soil particles and enclosure/binding with Ca/CaO-associated immobile salts. Results suggest that the nanometallic Ca/CaO mixture is suitable for use in immobilization of heavy-metal-contaminated soil under normal moisture conditions.