光电功能性分离膜的制备及其对水中有机污染物的光电联合去除机制研究

Trace toxic organic pollutants could not be removed effectively by traditional wastewater treatment plants, displaying negative effects on the aquatic ecology and health of human beings, even exhibiting acute toxicity to some aqueous organisms. The integration of photocatalysis and membrane gave an approach to the purification of the reluctant toxic substance and could alleviate membrane fouling. However, the low photoconversion is one of the main problems restricting the practical application of photocatalytic membrane. Aiming at improving the photoconversion, we put forward an idea that introduce a carbon layer under the photocatalytic layer, and pose a low potential on the electric carbon layer to inhabit the combination of photogenerated carriers and hence achieve the enhanced degradation and removal of pollutants. The main contents include: (1) Fabrication and characterization of electro-assisted photocatalytic membrane with visible or UV light response; (2) Develop the relationship between water treatment capability with photo and electric characteristics of composite membrane; (3) The separation and degradation mechanisms of typical organic pollutants with the composite membrane; (4) The optimization and modulation of the water treatment capability of the membrane. The main objectives of this program are to recognize the technical characteristics and pricinples of the enhanced removal of pollutants of the electro-assisted photocatalytic membrane, to elucidate the mechanisms of integrated photo, electricity and membrane, and to provide the scientific supports for the application of this novel technique for the advanced wastewater treatment.

痕量有毒有机污染物在传统水处理工艺中无法有效去除，对水生生态及人体健康产生不良影响。光催化与膜过滤的结合，可有效净化废水中风险性有机污染物，同时减缓膜污染。但在光与膜的耦合过程中，光能利用效率低是主要的技术瓶颈。本项目创新性地提出通过在光催化层与膜基底之间增加导电碳层，制成光电功能性分离膜，引入外加低压电场，有效抑制光催化过程中光生电荷的复合，从而显著提高污染物的去除效率。主要工作包括：具有可见光和紫外光响应的基于不同材料的光电功能性分离膜的制备及性能调控方法；分离膜的光学性质和电学性质与水处理性能间相关性的规律研究；分离膜对典型有机污染物的分离与分解机理；分离膜的水处理性能优化与调控。通过本项目的研究，认识光电功能性分离膜对污染物的强化去除的技术特性、过程原理，阐明光、电、膜之间的协同作用机理，为该技术的应用提供科学依据和理论支撑，为废水深度处理资源化利用提供一种高效的可实用化创新技术。

痕量有毒有机污染物在传统水处理工艺中无法有效去除，对水生生态及人体健康产生不良影响。光催化与膜过滤的结合，可有效净化废水中风险性有机污染物，同时减缓膜污染。但在光与膜的耦合过程中，光能利用效率低是主要的技术瓶颈。本项目结合光催化层和导电碳层构建光电催化功能性分离膜，在电的辅助下，抑制光生电子和空穴的复合，从而提高分离膜对痕量有毒有机污染物的去除能力，同时改善膜污染问题。针对水中难降解有机污染物的高效去除，本项目制备了TiO2/carbon/Al2O3、g-C3N4/CNT/Al2O3、氧化石墨烯、多孔碳基等多种具有可见光响应和紫外光响应的光电催化功能膜。建立了优化的制备方法，通过工艺条件的控制，对分离膜的光电性质及分离特性进行调控。获得了光、电以及光电催化功能分离膜对苯酚、染料、抗生素等有机污染物的去除规律。光电催化膜分离过程中苯酚去除率分别是单独光催化膜过程和单独膜分离过程的2.7倍和10.1倍。在天然有机物腐殖酸存在条件下，光电催化膜过程表现出较好的抗膜污染性能及有机物去除效果，膜通量是单独膜分离过程的2.3 -2.8倍。对地表水中的TOC、UV254、浊度和大肠杆菌都表现出较高的去除性能。浊度和大肠杆菌在光电催化膜过程中几乎被全部去除，TOC和UV254的去除率分别达到了70%和85%。通过本项目的研究，可认识光电催化分离膜对污染物强化去除的技术特性、过程原理，阐明光、电、膜之间的协同作用机理，为该技术的应用提供科学依据和理论支撑。