含铁介质用于修复砷污染土壤研究综述

Review of remedying the arsenic-contaminated soil with Fe-based media

原位固化/稳定化技术被认为是当前土壤砷污染修复中相对经济、高效的技术之一,含铁介质是土壤固砷的一类上佳材料。从含铁材料修复砷污染土壤的研究现状出发,阐述其固砷机理,主要包括吸附、络合作用以及沉淀/共沉淀作用。介绍了5种常用的固砷效果评价方法,分别为化学形态连续提取法、毒性特征浸滤法、植物指示法、体外消化模拟法以及现代物理学方法。阐述了土壤环境条件,如酸碱条件、氧化还原条件以及土壤中共存离子和有机质的变化对固砷效果的影响。总结了目前含铁材料用于修复砷污染土壤的不足之处,并指出了今后的研究重点。

Soil arsenic pollution has become an important environmental problem,which needs to solve urgently. In-situ solidification/stabilization technology has been shown to be one of the most cost-effective techniques,and Fe-based media is the best material for the immobilization of arsenic in soil. The paper proceeded from the research status of arsenic-contaminated soil remediation with typical iron containing materials and elaborated the mechanism for solidifying arsenic,including adsorption,complexation and precipitation/co-precipitation. The five commonly used methods to evaluate the efficiency of arsenic solidification were introduced,including chemical form sequential extraction procedure,toxicity characteristics leaching procedure,indicator plant method,in vitro digestion and modern physics method,respectively. The effect of soil environmental conditions,such as acid and alkali,redox conditions and the changes of coexisting ions and organic matter in soil,on arsenic fixation were also analyzed. The deficiencies of the present research on the application of iron containing materials in the remediation of arsenic contaminated soil were also summarized. Finally,the paper pointed out the research emphasis of soil-remediation with the iron-containing materials in the future.