基于提高•OH生成的石墨烯-金属氧化物复合催化低温等离子体机制及其高效降解POPs的应用研究

In view of the worsening pollution problem of the persistent organic pollutants (POPs) in water, it is of great significance to research and develop the high-efficiency degradation technologies for alleviating the water environment crisis. Depending on the advantage of the multi-effect catalysis of the metal oxides (WO3 and ZnO) due to their characteristics of visible-light response and catalysis on the active substances (H2O2 and O3), and using the graphene to enhance its catalytic ability, adsorptive property and service life, a new method of the organic compounds degradation based on the •OH production enhancement by the composite catalysis of the graphene-metal oxide on the non-thermal plasma is then provided in the research. Main contents of the research include: Investigating the effect of the generation methods of the pulsed discharge plasma (PDP) and the dielectric barrier discharge plasma (DBDP), as well as the constitution and the preparation method of the catalyst on the catalytic effect of the graphene-metal oxide composite catalyst; Analyzing the main factors affecting the catalytic process, controlling the catalytic efficiency and then attaining the high-efficiency degradation of the POPs; Detecting and analyzing the effect of operating parameters of the PDP system and the DBDP system, and the parameters of the catalyst on the energy utilization efficiency of the different non-thermal plasma systems, the light intensity, the formation and spatial distribution of the active substances, the degradation efficiency and mineralization efficiency of the POPs, and the degradation pathway of the POPs; Clarifying the catalytic effect of the graphene-metal oxide composite catalyst; Revealing the catalytic mechanism. The researching results will provide reference for enhancing the •OH production in the different non-thermal plasma systems, attaining the high-efficiency degradation of the POPs in water, and expanding the application of the graphene-metal oxide composite material.

针对日趋严峻的水体POPs污染问题，研发高效的降解技术对缓解水环境危机意义重大。研究依托金属氧化物（WO3和ZnO）具有可见光响应和活性物质（H2O2和O3）催化的多效催化优势，并利用石墨烯提高其催化能力、吸附性能和使用寿命，提出以提高•OH生成量为基础的石墨烯-金属氧化物复合催化低温等离子体降解有机物的新方法。本研究将考察脉冲放电等离子体、介质阻挡放电等离子体发生条件和催化剂组成、制备方法等对石墨烯-金属氧化物复合催化效应的影响规律，解析主导因素，调控催化效果，实现POPs高效降解；考察不同低温等离子体体系操作参数和催化剂参数对等离子体体系能量利用效率，体系中光谱强度、活性物质浓度和空间分布、POPs降解与矿化效率及POPs降解途径等的影响规律，明确催化效果，揭示催化机制。该研究对低温等离子体体系•OH产量的提高，水体POPs的高效降解，石墨烯-金属氧化物复合材料的拓展应用具有参考意义。

本项目针对日趋严峻的水体难降解有机物污染问题，依托金属氧化物具有可见光响应和活性物质（H2O2和O3）催化的多效催化优势，并利用石墨烯提高其催化能力、吸附性能和使用寿命，提出石墨烯-金属氧化物复合催化低温等离子体水处理方法。项目研究中成功制备了不同的纳米金属氧化物（ZnO和WO3）、不同的石墨烯-金属氧化物（石墨烯-TiO2、石墨烯-WO3、石墨烯-Fe3O4、石墨烯-WO3-Fe3O4）以及ZnO-纤维素膜复合催化剂，建立了基于脉冲放电等离子体和介质阻挡放电等离子体协同不同催化剂的水体难降解有机污染物处理体系，充分利用低温等离子体中的光、O3和H2O2实现不同催化剂的多效催化，证实了氟甲喹、恩诺沙星、氧氟沙星、甲砜霉素、磺胺嘧啶、双酚A和邻苯二甲酸二甲酯等难降解有机物降解率及相应低温等离子体体系能量利用效率的提高，给出了利于激发不同催化剂作用效果的低温等离子体发生方法及系统操作条件，并通过催化剂表征、光谱诊断、自由基电子自旋共振检测、活性物质浓度测试和自由基捕收剂添加实验，结合有机物的降解效率和矿化效率测试、三维荧光光谱分析、有机物中间产物及降解路径推测，深入分析了有机物降解过程的关键活性物质，归纳不同低温等离子体/催化剂协同体系的催化协同作用机制及有机物降解机制。研究的关键结果表明：优化研究后的低温等离子体可以高效激活不同催化剂的催化活性；研究中制备的石墨烯-金属氧化物复合催化剂光响应范围增加、电子-空穴对分离速率加快，进而可以大幅提高协同体系中有机物的降解效率及系统能效；石墨烯-金属氧化物除了具有光催化作用外，还可以促进O3分解产生•OH；在相同条件下不同石墨烯-金属氧化物催化降解相同有机物性能表现为：石墨烯-WO3-Fe3O4>石墨烯-Fe3O4>石墨烯-WO3>石墨烯-TiO2。该研究对低温等离子体体系•OH产量的提高，水体难降解有机物的高效降解，石墨烯-金属氧化物复合材料的拓展应用具有参考意义。