亚/超临界水中活性炭-沸石分子筛复合材料原位负载纳米零价铁对全氟化合物的催化降解机理研究

Aim at the problem of gradual increased environmental risk for PFCs-wastewater and impending requirement for performing 'Stockholm Convention' in China, we put up with the ideas that nanoscale zero-valent iron is supported by zeolite/activated carbon composite material from coal gangue and the laden catalysts are applied for effective degradation of PFCs in sub- and supercritical water. Based on degradation products and the change, occurrence configuration, distribution state and interfacial reaction mechanism of nanoscale zero-valent iron in the composite material, the catalytic degradation path and mechanism of PFCs will be clarified. Simultaneously, the mechanism of inhibition passivation layer growth are elucidated through role of carbon constituent in the composite materials. By study and discovery of these scientific question, technical difficulty is solved for passivation layer growth and selt-agglomeration influence on excellent capability of zero-valent iron particle in sub- and supercritical water. And, technological support is provided to effectively degradation for highly toxic and recalcitrant PFCs-wastewater.

针对我国全氟化合物（PFCs）污水的环境风险逐年增加问题，结合国家履行《斯德哥尔摩公约》的迫切需求，本项目提出由煤矸石制备的活性碳-沸石分子筛复合材料负载纳米零价铁应用于亚/超临界水中 PFCs高效降解的研究设想。从降解产物种类以及复合材料基体中纳米零价铁的去向、赋存形态、分布状态及其表面的界面反应机制，揭示典型PFCs在负载型纳米零价铁上的催化降解过程和机理；同时解析反应过程中复合材料的炭组分抑制纳米零价铁颗粒表面钝化层生成的机理。通过这些科学问题的研究和探索，解决亚/超临界水反应条件下制约纳米零价铁颗粒高性能发挥所面临的自发团聚和生成钝化层的技术难题，为污水中高毒性、难降解PFCs高效降解提供技术支撑。

应用球磨技术成功制备了Fe0/ZSM-5复合材料，并利用 XRD、SEM、BET、XPS 等手段对球磨复合材料进行表征。研究了粉体和片状Fe0/ZSM-5复合材料对溶液中的Pb2+以及模拟电镀废水中的Cr6+、Cu2+、Cd2+和Pb2+等多种重金属的去除效果; 将零价铁应用于焚烧飞灰中重金属的去除，探讨了洗脱液的pH值、反应温度、零价铁投加量、处理时间、粒径大小等影响因素条件下对焚烧飞灰中重金属的去除效果。在球磨条件下，研究了零价铁对于锥玻璃中铅的回收效果，通过改变零价铁的投加量，零价铁粒径，球磨转速，球磨时间等变量，优化了锥玻璃中铅在酸液中的最佳浸出条件。以典型全氟化合物PFOS和PFOA为研究对象，采用可控间歇和连续式亚/超临界水反应装置，配合负载型纳米零价铁，通过考察一系列反应参数（如反应温度、反应时间、污染物浓度、流速等）对中间产物生成种类的影响，系统研究还原条件下PFOS和PFOA的降解特性。