Wang Lin, Xu Ying-Ming, Liang Xue-Feng, Sun Yang, Qin Xu
Department of Pollution Control, Institute of Agro-Environmental Protection, Ministry of Agriculture, Tianjin 300191, China.
Huan Jing Ke Xue. 2011 Feb;32(2):581-8.
The effect of new hybrid material and its compound treatments with phosphate on immobilization of cadmium and lead in contaminated soil was investigated using a pot-culture experiment, and the immobilization mechanism of hybrid material was clarified through analysis of heavy metal fractions, sorption equilibration experiment and X-ray photoelectron spectroscopy (XPS). The single treatments of hybrid material could not significantly promote growth of Brassica chinensis, while the compound treatments of hybrid material and phosphate markedly increased dry biomass of shoots and roots, with maximal increases of 75.53% and 151.22%, respectively. Different hybrid material treatments could significantly reduce Cd and Pb concentrations in shoots, with maximal reductions of 66.79% and 48.62%, respectively, and the compound amendment treatments appeared more efficient than the single amendment treatments in reducing Cd and Pb uptake of B. chinensis. Different hybrid material treatments could significantly decrease concentrations of toxicity characteristic leaching procedure (TCLP) extractable Cd and Pb, and the compound hybrid material treatments appeared more efficient than the single treatments in reducing TCLP extractable Cd and Pb. Through the formation of bidentate ligand between metal ions and surface sulfhydryl by complexing reaction, the hybrid material could absorb and fix mobile fractions of Cd and Pb in soil, and promote transformation of acid extractable Cd and Pb into residual fraction, resulting in significant reduction of heavy metals bioavailability and mobility and then fixing remediation of contaminated soil. In summary, the compound treatment of hybrid material and phosphate is the most effective treatment for immobilization of Cd and Pb in contaminated soils, and the hybrid material inactivates Cd and Pb in soil mainly through special chemical adsorption.
通过盆栽试验研究了新型混合材料及其与磷酸盐复合处理对污染土壤中镉和铅的固定效果，并通过重金属形态分析、吸附平衡试验和X射线光电子能谱（XPS）阐明了混合材料的固定机理。混合材料单施不能显著促进小白菜生长，而混合材料与磷酸盐复合处理显著增加了地上部和根部的干生物量，分别最大增加了75.53%和151.22%。不同混合材料处理能显著降低地上部镉和铅浓度，分别最大降低了66.79%和48.62%，且复合改良处理在降低小白菜镉和铅吸收方面比单施改良处理更有效。不同混合材料处理能显著降低毒性特性浸出程序（TCLP）可提取的镉和铅浓度，且复合混合材料处理在降低TCLP可提取的镉和铅方面比单施处理更有效。通过络合反应在金属离子与表面巯基之间形成双齿配体，混合材料可吸收并固定土壤中镉和铅的可移动形态，促进酸可提取态镉和铅向残渣态转化，从而显著降低重金属的生物有效性和迁移性，进而实现污染土壤的固定修复。综上所述，混合材料与磷酸盐复合处理是污染土壤中镉和铅固定的最有效处理方法，混合材料主要通过特殊化学吸附使土壤中的镉和铅失活。
