报 告 人：郑建中 教授    

中国科学院大学
报告时间：2019 年 11 月 1 日 9:00-11:00
报告地点：环境与规划学院四楼研讨厅
主办单位：环境与规划学院
邀 请 人：段海静 博士
主 持 人：李旭辉 副教授
报告人简介：郑建中，中国科学院大学资源与环境学院教授，博士生导师。2001 年获美国克拉克森大学土木与环境工程系环境工程专业博士学位。目前主要从事受污染 (重金属、含氯有机溶剂、原油及油品) 土壤-地下水系统的修复，油田油泥高效处置技术研究，页岩气产出水中盐分及代表性特征污染物处理技术研究，新型环境功能材料的研究及应用，以及环境胶体与界面化学等相关领域的研究工作。
观点综述： The anoxic reduction of lepidocrocite by polysulfide was studied under alkaline conditions (pH 9.5), and the reducing capacity of the resultant reduced lepidocrocite (RL) for hexavalent chromium (Cr(VI)) reduction was examined in the pH range from 6 to 10. The results indicated that polysulfide had a high reactivity in reducing lepidocrocite at pH 9.5. Elemental sulfur was the main product from polysulfide oxidation, and the produced ferrous iron was mainly distributed in solid and adsorbed forms, with much less observed in the dissolved state. RL maintained a good reducing activity in the pH range from 6 to 9. X-ray photoelectron spectroscopy analysis suggests that both Fe(II) and the reduced sulfur species in RL participated in Cr(VI) reduction. The possible reaction paths of lepidocrocite reduction by polysulfide were proposed and consistent with the observed changes in reactants and products, and the reaction process may involve the adsorption of polysulfide, the electron transfer, and the detachment of produced Fe(II). This work also explained why polysulfide could maintain a prolonged reducing condition in field remediation of Cr(VI)-contaminated soil and groundwater.
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