nFeS介导过硫酸盐体系修复地下水氯代烃污染脱氯机理及其多自由基生成驱动机制

当前地下水有机污染日益凸显，氯代烃类有机物因其高毒性、高富集性、高环境残留的特点，易造成地下水大面积、持久性污染，研发高效的地下水氯代烃污染原位修复技术已刻不容缓。活化过硫酸盐氧化法因其无毒、高效、经济且环境友好等优势在地下水污染原位修复研究中得到了广泛关注。本项目拟融合FeS表面元素Fe(II)和S(-II)可同时作为电子供体的优点，以地下水中典型氯代烃—三氯乙烯为修复对象，通过制备粒径和分散性可控的纳米FeS活化剂，研究nFeS介导下活化过硫酸盐体系降解氯代烃的脱氯过程、中间产物以及反应动力学等，揭示nFeS表面Fe、S元素的价态转化、驱动Fe(II)/Fe(III)循环和氯代烃降解效率之间响应关系，阐明不同水化学条件下的nFeS介导氯代烃有机物的降解路径和不同自由基生成驱动机制，为利用FeS活化过硫酸盐体系高效修复地下水氯代烃有机物污染提供理论指导和技术支撑。

The organic pollution of groundwater is a growing problem recently. Chlorinated hydrocarbon organic compounds are easy to cause long-term contamination of groundwater in a large area because of high toxicity, high enrichment and high environmental residue. Therefore, it is urgent to develop efficient in-situ remediation technology for chlorinated hydrocarbon pollution of groundwater. Activated persulfate oxidation has received extensive attention in the field of in-situ remediation of groundwater pollution due to its advantages of non-toxicity, high efficiency, economy and environmental friendliness. This research proposal is intended to integrate the surface elements Fe(II) and S(-II) of FeS as both electron donors. Trichloroethylene is used as the typical chlorinated hydrocarbon contamination compound in groundwater remediation. The preparation method of nanoscale FeS activator with controllable particle size and dispersion will be investigated. The dechlorination process, intermediate products and reaction kinetics during the groundwater remediation of chlorinated hydrocarbon pollution under nFeS mediated conditions will be studied. The chemical response relationship between the valence transformation, Fe(II)/Fe(III) cycle and the repair efficiency of FeS surface elements Fe and S will be revealed. The dechlorination pathway and mechanism of free radical interaction of nFeS mediated chlorinated hydrocarbon under various of hydrochemical conditions will also be elucidated. In summary, this proposal will provide theoretical support and new technical methods of activated persulfate systems for the effective remediation of chlorinated hydrocarbon organics pollution in groundwater.