基于污染物形态识别的无机膜光催化耦合工艺中膜污染机理与控制研究

According to the property of membrane fouling under the effect of photocatalysis, the analysis of the membrane main pollutants and them morphological identification will be performed using humic acid wastewater as study subject, and the mechanisms of membraAccording to the characteristics of membrane pollution under the effect of photocatalysis, the analysis of the membrane main pollutants and them morphological identification will be performed using humic acid wastewater as study subject, and the mechanisms of membrane fouling caused by the coexistence effect among the multicomponent substances will be investigated in the process of coupling photocatalysis with inorganic membrane. Then the control countermeasures of the membrane pollution will be explored. The change trends of the concentrations, compositions and molecular weight distribution of the pollutants in the degradation solutions will be analyzed. Microscopic analysis and identification will be performed on the purpose of comprehending the main compositions of pollutants and them morphologies from the gel layer, membrane surface and membrane pore. The influences of acting mechanisms and coexistence effects among the catalysts, humic acid and intermediate charactene fouling caused by the coexistence effect among the multicomponent substances will be investigated in the process of coupling photocatalysis with inorganic membrane. Then the control countermeasures of the membrane fouling will be explored. The change trends of the concentrations, compositions and molecular weight distribution of the pollutants in the degradation solutions will be analyzed. Microscopic analysis and identification will be performed on the purpose of comprehending the main compositions of pollutants and them morphologies from the gel layer, membrane surface and membrane pore. The influences of acting mechanisms and coexistence effects among the catalysts, humic acid and intermediate characteristic products on membrane fouling will be analyzed. Membrane fouling models will be fitted using different filtration models, including the resistance models, blocking models, concentration polarization models and so on. Some model parameters will be properly compared and revised. From the macroscopic perspcetive, the membrane fouling mechanisms caused by the coexistence effect among the multicomponent substances will be investigated under the effect of photocatalysis. The combination experimental schemes with different system parameters will be compared, so as to analyze the effects of the process conditions，solution characteristics and membrane parameters on the effluent quality, membrane fouling resistance and critical flux, respectively. Moreover, the effective controlling measures will be rearched for showing good anti-pollution characteristics of the membrane. There will be very important guiding significances of the research results to develop novel photocatalytic membrane reactors and optimize the operation process.

本项目针对分离膜在光催化作用下的污染特性，以腐植酸模拟废水为研究对象，对无机膜光催化耦合工艺中的主要膜污染物及其形态进行分析与识别，研究光催化膜耦合工艺过程中的多组分共混效应形成膜污染机理，以此探求光催化作用下膜污染控制对策。将分析降解液中污染物浓度、分子量分布及主要组成的变化规律，并对凝胶层、膜表面和膜孔内污染物的主要组成及其形态进行微观分析与识别；考察催化剂/腐殖酸/中间特征产物间的作用机制及其共存效应对膜污染的影响；利用膜过滤数学模型-阻力模型、堵塞模型及浓差极化模型等进行拟合,比较模型参数并合理修正，从宏观角度探明光催化效应下多组分共混效应形成膜污染机理；以不同系统参数组合试验方案进行对比，考察工艺操作条件、体系特征、耦合膜参数对出水水质、膜污染阻力以及临界通量的影响，寻求出膜污染的有效控制对策。本课题研究结果对新型光催化膜反应器设计及工艺运行的优化具有重要的指导意义。

针对光催化膜反应器及工艺过程中的膜污染特性，以腐植酸模拟废水为研究对象，对无机膜光催化耦合工艺中的主要膜污染物及其形态进行分析与识别。利用微观表征手段分析凝胶层、耦合膜表层和膜孔内污染物的主要形态、组成及比例，考察催化剂/腐殖酸/中间特征产物间共存效应对膜污染的影响。采用Hermia经典阻塞模型来对膜过滤过程进行拟合与修正，分析了各膜过滤模型的吻合度，判断膜污染机理类型。对滤饼系数、堵塞因子及阻力分布等参数进行计算与分析，提出临界通量、亚临界通量工艺控制膜污染策略。光催化氧化可有效减缓多通道陶瓷超滤膜错流工艺中膜通量的衰减及提高污染物去除率。催化剂浓度为0.4g/L时，膜污染总阻力、可逆污染阻力及不可逆污染阻力达到最低，分别为9.82×1011 m–1、1.28×1011 m–1及2.95×1011m–1。UV/TiO2光催化超滤膜工艺中的膜污染可以采用初始阶段中间孔堵塞，中间过渡膜污染和最后为限制性滤饼生长的机制模型描述发展历程。光催化作用使得降解液中更多HPO-HA分子转化为HPI组分。与HPO分子相比，HPI组分可能更容易从膜表面迁移到溶液中。UV/TiO2光催化将产生高MW（>50kDa）的HPI类腐殖质物质容易被截留，并与TiO2颗粒混合形成多孔滤饼层。临界通量运行周期更长，渗透滤液体积更多，其膜污染首先经历缓慢增长过程，达到一定程度后变为加速膜污染过程。PMR/DM工艺利用光催化氧化提高了滤饼层的孔隙率和亲水性，能有效降低可逆膜污染。在PMR/DM亚临界通量运行工艺中将具有高分子量HPO的HA分子与羧酸官能团和芳香族结构转化为低分子量HPI或TPI组分，包括色氨酸类或黄腐酸类物质，形成更多孔滤饼层。PMR/DM中的动态层阻止了污染物尤其是高MW的HPO组分与基膜接触，减少不可逆污染，膜渗透性容易通过物理清洗恢复。本研究能对光催化膜工艺理论的进一步深入发展提供基础数据，还能为新型光催化膜反应器及相关工艺设计及运行的优化提供良好的指导，并对光催化、膜材料开发、分离膜制备与筛选、新型催化剂研制、废水处理工艺设计与运行等一系列技术研发提供帮助。另外，本项目以水体大量存在的天然有机物（腐植酸）为研究对象，研究结果还能有效促进江西省特别是环鄱阳湖区域微污染水的绿色处理工艺的发展，对发展江西生态经济、保护鄱阳湖“一湖清水”均具有十分重要的意义。