基于SO4•–的非均相类Fenton/光催化协同纳米反应器构筑及协同反应机制

Compared with homogeneous Fenton, the Fenton like reaction based on KHSO5 catalyzed by Co2+ to produce SO4•– (SR-Fenton) has the advantages of no chemical sludge producing and a wide pH adaptability. However, the Co2+ ions are toxic and the reaction products of SO42– ions will increase water salinity, moreover, the controllability of the radical oxidation reaction between SO4•– and organics is weak, so many by-products will generate. These drawbacks limit the application of homogeneous SR-Fenton. This project propose a new idea that using nanoreactor as the media to combine heterogeneous SR-Fenton and photocatalysis. It reduces the risk of large quantity of Co2+ ions leaching to the water by using heterogeneous reaction and enhances the heterogeneous SR-Fenton catalysis by using photocatalysis. It also can decrease the dosage of KHSO5 using in SR-Fenton process. Furthermore, the nanoreactor will be used to control the reaction process through “adsorption – enrichment – confinement oxidation” of organic pollutant molecules. The project is expected to develop a heterogeneous SR-Fenton/photocatalysis synergistic nanoreactor and build a new synergistic oxidation system to achieve efficient removal of organic contaminants in water. The project is proposed to study the heterogeneous synergistic SR-Fenton/photocatalysis mechanism in-depth by using in-situ technologies like XPS and EXAFS; and reveal the impact mechanism of nanoreactor for the synergistic system. The research results can establish the theoretical basis for the application of this system.

与均相Fenton相比，以Co2+催化KHSO5产生SO4•–的类Fenton反应（SR-Fenton）有pH适应力强、无化学污泥的优点。但Co2+有毒，产物SO42–会增加水体盐度且SO4•–降解有机物的反应可控性差，副产物多，限制了其应用。本项目提出以纳米反应器为介质协同非均相SR-Fenton和光催化的新思路。以非均相反应减少Co2+进入水体；以光催化强化非均相SR-Fenton催化过程，减少KHSO5的使用量并利用纳米反应器对反应进行过程控制，通过对有机污染物分子的“吸附—富集—限域氧化”增强反应可控性。项目预期开发一种非均相SR-Fenton/光催化协同纳米反应器并构建新型协同氧化体系，实现高效去除水中的有机污染。项目拟通过XPS和EXAFS等原位技术深入研究非均相SR-Fenton和光催化的协同机制，揭示纳米反应器对协同体系的影响机理。研究成果可为该体系的实际应用奠定理论基础。

由于Co2+催化KHSO5产生SO4•–的类Fenton反应（SR-Fenton）有pH适应力强、无化学污泥的优点。但Co2+有毒，产物SO42–会增加水体盐度且SO4•–降解有机物的反应可控性差，副产物多，限制了其应用。为了增强SR-Fenton反应的可控性以及技术实用性，本项目利用试验与理论分析等研究手段，开展了具有非均相SR-Fenton活性的纳米反应器研发，与KHSO5构建了非均相SR-Fenton协同纳米反应器的催化氧化体系。通过对水中多种代表性难降解有机物苯酚、罗丹明B和双酚A的降解效果评价，结合XRD、XPS、STEM-EDS等多种表征手段探明了纳米反应器结构、催化活性点位和协同作用，以及pH值、催化剂和KHSO5投加量对反应进程的影响；同时通过LC-MS等手段跟踪有机物降解中间产物证明了可通过纳米反应器的独特结构对催化氧化反应进行“过程控制”。此外，进一步将光催化过程耦合进非均相SR-Fenton催化氧化体系，建立了非均相SR-Fenton/光催化协同催化氧化体反应系，进一步研究阐明了光催化、SR-Fenton和纳米反应器三者之间的协同作用，并在保证降解率的前提下，实现了KHSO5和催化剂投加量有显著降低，并结合特拉锚垫材料初步开发适用于航道岸坡水环境原位修复的功能材料。