多时间尺度可控缓释材料开发及其去除地下水中Cr(VI)污染机制研究

本研究针对纳米零价铁(nZVI)在地下水污染修复中存在的易团聚，去除污染物过程中长时间尺度下活性损失过快的难题，以典型的地下水中铬污染为研究对象，基于层层溶蚀结构开发可控缓释铬修复材料并研究其对铬的去除机制。一方面，通过调控每层nZVI嵌入间距，达到可控调节单次释放的活性nZVI总量；另一方面，通过精准设计多层中每层的溶蚀结构和采用不同溶蚀速率的基材，达到精准调控每层缓释材料的释放时间(分钟、小时、天、月、年)。同时研究地下水水化学条件对多尺度时间可控nZVI缓释材料作用效能的影响机制，评估nZVI缓释材料为填充介质的模拟渗透反应墙(PRB)系统对于地下水中Cr(VI)修复效能，定量刻画地下水污染情景参数和nZVI缓释材料修复性能之间的函数关系，为nZVI在地下水修复中的实际应用和构建高效可持续的铬污染地下水PRB修复系统提供理论与技术支持。

This study is aimed at the problem of the agglomeration and fast deactivation for a long-time scale treatment of nano-zero-valent iron (nZVI) in groundwater pollution remediation process. The typical chromium pollution in groundwater is taken as the object. Based on the layered dissolution structure, the controlled slow release chromium remediation materials are developed, and the mechanism of chromium removal is investigated. On the one hand, the total amount of the released active nZVI for a single release is controlled by adjusting the intercalation spacing of each layer.On the other hand, the release time (minute, hour, day, month, year) of the slow release material is precisely controlled by accurately designing the dissolution structure and using substrate materials with different dissolution rates. The influence mechanism of groundwater hydrochemical conditions on the efficiency of the slow release material is studied. The functional relationship between the groundwater pollution scenario parameters and the remediation performance of nZVI slow release materials is quantitatively described. Evaluation of Cr(VI) remediation efficiency in groundwater by simulating permeable reactive barrier(PRB) system with multi-scale time controllable nZVI slow release material as filling medium. These can provide theoretical and technical support for the practical application of nZVI in groundwater remediation and the construction of efficient and sustainable PRB remediation system for chromium contaminated groundwater.