耐腐蚀电催化多孔膜电极的制备及催化性能研究

Electro-catalytical membrane reactor (ECMR) can integrate the advantages of electro-catalysis and membrane filtration to solve the key problem of these two methods in energy efficiency and reactor efficiency. In the new reactor, the evolved gas during electro-catalysis is used to prevent the membrane fouling and the driving force of membrane process is used as the driving force of the mass transportation of electro-catalysis. However, the corrosion of membrane electrode is the bottle neck of the development of the ECMR. The membrane is one kind of porous material with pore size less than 1 micron. The coating method for anti-corrosion of general electrode doesn’t meet the requirement for the membrane electrode to keep the pore structure and anti-corrosion. In this project, we will develop a conductive and anti-corrosion basic membrane material. Based on the preparation of the membrane material, we will deeply investigate the principle and method of the preparation, design and pore structure control of the membrane. The intrinsic relationship between the electro-catalytic activity and the pore structure and composition of the membrane will be brought insight. The energy efficiency and anti-fouling mechanism of the ECMR will be investigated to announce the principle and method for optimization of the ECMR. The theory and method of the design of membrane electrode will be enriched to put forward the ECMR.

电催化膜反应器可以有效实现电催化和膜过滤的优势互补，解决这两种污水处理方法的能量效率和反应器效率低的共性关键问题。电催化过程的析气效应用于膜污染抑制，膜过程的推动力同时用作电催化过程的传质推动力，实现能量的高效化并提高反应器效率。但是，膜材料的腐蚀问题是这一新方法发展的瓶颈。膜材料为多孔材料，孔尺寸一般小于1微米，既要实现抗腐蚀又要保证孔结构，无法采用普通电极材料的表面涂层方法实现防腐蚀。针对这一问题，本项目旨在发展一种导电、耐腐蚀的电催化膜基体材料，从基体膜材料制备出发，深入研究膜材料的孔结构和表面组成设计原理及制备方法，揭示膜孔结构和组成与其电催化活性之间的构—效关系。探究有机污染物在电催化膜上的降解机理，尤其是在膜的纳米孔道内的降解机理。研究电催化膜反应器的膜污染抑制机理及能量效率，在此基础上阐明基于新型膜材料的反应器优化原理和方法，为电催化膜反应器的发展提供理论依据和技术指导。

膜电极的耐腐蚀性和催化活性是电催化膜反应器发展的关键。膜电极一般为多孔材料，孔尺寸小于1微米，既要实现抗腐蚀又要保证高孔隙率，故无法采用普通电极材料的表面涂层方法实现防腐蚀。因此，制备一种基体耐腐蚀的多孔电极材料是解决这一问题的关键。本项目成功制备了耐腐蚀阳极膜材料—碳化铌膜和碳化硅膜，并将其应用于电氧化去除水中污染物，获得了良好的去除率和选择性。采用碳热还原法制备碳化铌，并在碳化铌膜上负载氧化钌（RuO2），探究了烧结温度及碳化温度对膜表面微观形貌及晶相的影响，着重研究了催化组分负载量及反应器过程参数对苯酚去除的影响。在流经式反应器中，RuO2/NbC电极的苯酚去除率可达100%，COD去除率和平均电流效率分别为71.30%和85.22%。在氧化铌支撑体表面涂覆纳米粉体来构筑分离层，碳化后获得非对称碳化铌膜，负载金属铂（Pt）得到Pt/NbC电极用于流通式反应器，去除水中苯酚，Pt/NbC阳极的苯酚去除率和COD去除率分别为99%和65%。采用固态粒子烧结法，以聚碳硅烷（PCS）为粘结剂，以碳化硅粉为原料，烧结制备得到碳化硅膜。探究了烧结温度及PCS添加量等对膜结构的影响。考察了电流效率及苯酚初始浓度对苯酚去除的影响。在流经式反应器中，苯酚的去除速率为65.16%，COD的去除效率为20.63%。在碳化硅表面涂覆纳米碳化硅来制备非对称碳化硅膜，负载RuO2得到RuO2/SiC电极，并应用于流通式反应器，RuO2/SiC膜的苯酚去除率和COD去除率分别为87.21%和64.31%。耐腐蚀碳化物膜的成功制备有望为电催化膜反应器在水污染治理领域的发展奠定基础。