构筑yolk/shell型微反应器进行串联反应实现有机物Fenton降解

Fenton reaction was one of the most effective methods for degradation of organic pollutants in waste water. However, there were three main drawbacks in traditional heterogeneous Fenton system: low reaction rate, low utilization efficiency of H2O2, leaching and aggregation of catalysts. To solve these problems, a novel experimental project with the title of “preparation of microreactor with yolk/shell structure to perform Fenton degradation of organic pollutants by tandem reaction”, was designed. The yolk/shell microreactor consisted Fe3O4 nanoclusters as inner core, and PPy layer whose inner surface was embedded with metal nanoparticles as outer shell. In microreactor, H2O2 was in-situ generated on the surface of metal nanoparticles via catalytic reaction; then the as-prepared H2O2 converted to ·OH on Fe3O4 nanocluster surface, and heterogeneous Fenton reaction was initiated to degrade organic pollutants. With the help of confined effect, protective effect and in-situ generation method of H2O2, the aforementioned three problems were solved together. Moreover, it was convenient for us to control reaction process in such continuous tandem reaction. This project not only designed a novel way to construct heterogeneous Fenton system, but also explored the new application of microreactor in tandem reaction. In addition, the contributions and advantages of “tandem reaction” microreactor in heterogeneous Fenton degradation could be systematically recognized. Therefore, this project had positive scientific significance and wide application prospect.

Fenton反应是降解污水中有机物最有效的方法之一。然而，传统多相Fenton体系存在反应速率慢、H2O2利用率低和催化剂易流失团聚三个主要缺陷。为此，本项目设计了“构筑yolk/shell型微反应器进行串联反应实现有机物Fenton降解”的实验方案。新型微反应器以Fe3O4纳米簇为核，内表面镶嵌金属纳米粒子的聚吡咯为壳。微反应器内，初始原料在金属纳米粒子表面原位生成H2O2，H2O2在Fe3O4纳米簇表面转化为·OH引发Fenton反应降解污染物。该方案将微反应器的限域效应、保护作用与H2O2原位生成的方式结合在一起，不仅能够同时改善上述不足；而且，这种连续进行的串联反应模式，为操控反应过程提供了方便。本项目的实施，既是对构建新型多相Fenton体系的研究，又是对微反应器进行串联反应的探索；还可以系统认识串联反应微反应器在Fenton降解中的贡献与优势，因而具有积极的科学意义与应用前景。

当前，有机物造成的水污染严重危害着人类的生存环境和健康生活。如何高效处理此类污染物成为人们日益关心的问题。为此，本项目设计了“制备yolk/shell型微反应器进行串联反应实现有机物Fenton降解”的实验方案。新型微反应器以Fe3O4纳米簇为核，内表面镶嵌金属纳米粒子的聚吡咯为壳（Fe3O4/M@PPy：M为金属纳米粒子，PPy为聚吡咯）。研究结果表明，相比于传统催化剂，yolk/shell型微反应器的设计，加快了反应速率、抑制了纳米粒子团聚和金属离子流失、提高了H2O2利用效率，对改善多相Fenton反应具有积极意义。在该研究基础上，围绕“高效处理有机污染物”这一课题，本项目还制备了多种以PPy为载体的铁基纳米材料，并将其应用于多相Fenton、光Fenton和微波Fenton反应降解有机污染物。在这些研究中，我们着重考察了催化活性、循环利用性、金属离子流失、污染物降解路径、催化反应机理和构效关系等关键问题，加深了对Fenton反应在污染物降解领域的认识。很多体系中，有机污染物可在数分钟内完全降解，矿化效率高达80%以上，多次循环使用催化活性无明显下降，金属离子的流失量远低于国家排放标准。本项目的研究成果，为污水中有机物的处理开辟了新的思路，对我国的环境保护具有重要意义。