Zn基电絮凝修复地下水中多氟及全氟化合物污染的调控技术原理研究

Dr. Hui Lin will sever as the PI of this proposal aiming to explore a novel electrocoagulation technique with zinc anodes to efficiency remediation of groundwater contaminated by poly- and/or perfluoroalkyl substances (PFASs). Analysis and separation methods will be developed to identify the floc species formed by Zn2+ hydrolysis. Subsequently, the physical and chemical properties of various floc species will be thoroughly characterized. By revealing the floc species generated by Zn2+ hydrolysis with PFASs adsorption activity, the structure-activity relationship between the floc species and PFASs removal efficiency will then be constructed. In view of tuning the floc species during electrocoagulation process with zinc anodes, the effect of hydrodynamic condition, complex environmental matrix including Cl-, SO42-, CO32-/HCO3-, turbidity, and dissolved organic matter (DOM), and introduction of Al3+ on the effectiveness of PFASs removal will be investigated systematically. Finally, the optimized electrocoagulation technique with zinc anodes will be evaluated to remediation of PFASs contaminated groundwater provided by AECOM Inc. at a laboratory scale. In addition, we will also explore the reuse and harmless disposal methods of the sludge containing PFASs produced from the remediation process. Finding in this proposal will provide the theoretical basis and basic data for tuning electrocoagulation with zinc anodes, and provide technical support for the remediation of PFCs contaminated water.

本项目以揭示Zn2+水解聚合絮体形态与多氟及全氟化合物（PFASs，如PFOA和PFOS）去除效率之间的构-效关系为切入点，通过发展Zn基电絮凝调控技术原理，实现PFASs污染地下水高效修复。主要研究内容：（1）通过发展Zn2+水解聚合絮体形态分析及表征方法论，鉴别出具有PFASs吸附活性的絮体形态，并构建出絮体形态与PFASs去除效率之间的构-效关系；和（2）从调控Zn2+水解聚合絮体形态的视角研究流态、复杂背景基质或同步引入Al3+作用下如何影响Zn基电絮凝去除PFASs的有效性，发展出Zn基电絮凝调控技术原理。此外，系统评估Zn基电絮凝用于地下水污染修复的有效性，明确对各种PFASs的有效适用范围，并探索产生的絮体污泥资源化回收利用和无害化处理处置方法。研究结果将为Zn基电絮凝调控提供基础数据和理论依据，也为PFASs污染水体控制及修复提供技术支撑。

本项目针对多氟及全氟化合物（PFAS）水环境污染控制修复面临的挑战，通过发展Zn基电絮凝调控技术原理，以实现PFAS工业污水的有效控制及污染水体的高效修复。主要发现与研究结论：1）共存复杂背景基质会严重干扰Zn基电絮凝去除PFAS的有效性，Zn絮体原位生成在线投加是可行的解决方案；2）同步引入Al3+能够通过原位生成ZnAl-LDHs，进而提高PFOA的去除效率，典型无机离子（Cl-和CO32-/HCO3-）对该方式去除PFAS产生竞争；3）提出了蕴含PFAS源内中性丢失特性给合同位素异数体分布特征算法的超分辨质谱筛查新方法，实现了氟化工污水中PFAS的全面表征，发现了多达175种PFAS，并首先发现报道了一类新型PFAS—碘代多氟烷基酸（I-PFAA），拓展了学术界对PFAS的新认识；4）追踪研究了氟化工污水中59种不同结构的PFAS，结果表明Zn基电絮凝对Cl/I-PFAS去除效果最为显著，同时能够有效去除PFCA（≥C6）和H-PFCA（≥C7），并有效削减C5及更长碳链的Ether-PFAS；5）受共存基质影响，活性炭/离子交换树脂均无法有效从氟化工污水中去除PFAS，通过耦合Zn电絮凝和活性炭/离子交换树脂吸附工艺能够去效大部分PFAS，且活性炭/离子交换树脂吸附柱完全穿透时间均大幅延长2~4倍；6）基于高催化活性Ti4O7膜电极的Flow-through电催化体系能够有效处理Zn基电絮凝处理氟化工污水产生的絮体污泥酸化污水，选取监测的40种PFAS均被有效降解。