地表水超滤过程中化学不可逆膜污染微观作用机理及控制研究

Membrane fouling is the hotspot and difficult issue in the membrane technology for water treatment, which is also the bottleneck for its application and popularization. Chemically irreversible fouling (CIF) cannot be cancelled by chemical cleaning, and foulants will be persistently accumulated in the structure of membrane, which have a direct impact on the lifespan of the membrane. In order to solve this problem, this project comprehensively investigates the main foulants, microcosmic mechanism and control technology of CIF during ultrafiltration (UF) for surface water treatment in the Pearl River Delta region. The characteristics of natural organic matter such as hydrophobicity-hydrophilicity and molecular weight distribution in source waters will be determined, and the main CIF foulants will be identified via correlating these characteristic components to the CIF and also analyzing the contribution of these components to CIF. Based on Hermia blocking model, XDLVO theory and Quartz-crystal microbalance with dissipation (QCM-D) technology, the blocking mechanism, interfacial free energy and interfacial adsorption behavior of CIF will be analyzed in order to reveal the microscopic mechanism of CIF. The effects of coagulation (polyaluminium chloride) adsorption (powdered activated carbon), oxidative (ozone) pretreatments on CIF control and co-control will be investigated, and then the effective control strategy will be proposed. The results of this study are expected to provide useful information for prolonging the lifespan of the membrane and ensuring the stable operation of UF process.

膜污染是膜法水处理领域研究的热点和难点问题，是膜技术应用和推广的瓶颈。化学不可逆污染（CIF）不能够通过化学清洗而消除，污染物会长期在膜内积累，直接影响膜的使用寿命。为了解决这一问题，本项目以珠三角地区典型地表水源为超滤进水，系统地研究CIF污染物主要成分、污染机理及控制技术。通过对超滤进水特性如天然有机物的亲疏水性、分子量分布进行测定，分析水质特性成分与CIF的相关性及对CIF的贡献，来识别CIF污染物主要成分；借助Hermia孔堵模型、XDLVO理论及耗散型石英晶体微天平（QCM-D）技术，探究CIF主要成分的孔堵机理、界面自由能及界面吸附行为，揭示CIF的微观作用机理；考察混凝（聚合氯化铝）、吸附（粉末炭）、氧化（臭氧）预处理对CIF的控制效果，明确预处理组合对CIF的协同控制机制，提出有效的CIF污染控制策略。研究成果对于延长膜的使用寿命，保证超滤工艺的稳定运行具有重要的意义。

膜污染是膜法水处理领域研究的热点和难点问题，是膜技术应用和推广的瓶颈。化学不可逆污染（CIF）不能够通过化学清洗而消除，污染物会长期在膜内积累，直接影响膜的使用寿命。为了解决这一问题，本项目以珠三角地区典型地表水源为超滤进水，系统地研究CIF污染物主要成分、污染机理及控制技术。通过对超滤进水特性如天然有机物的亲疏水性、荧光组分进行测定，分析水质特性成分与CIF的相关性，并采用红外（FTIR）手段对污染前后的膜进行表征，来确定CIF污染物主要成分为中性亲水性多糖类物质；利用Hermia模型从污染物与膜孔尺寸角度分析CIF物质对超滤膜的孔堵机理；利用XDLVO理论从界面作用能角度揭示CIF污染物与超滤膜之间的界面作用变化行为；利用QCM-D技术探究CIF污染物在超滤膜表面的微观吸附行为；考察原水特性、膜特性、水溶液化学条件变化对CIF污染行为的影响规律；进而从不同的角度来揭示CIF的微观作用机理。研究混凝（聚合氯化铝）、吸附（粉末炭）、氧化（高锰酸钾）预处理对CIF的控制效果，明确预处理组合对CIF的协同控制机制，最终提出CIF的最优控制策略为聚合氯化铝（20mg/L）+粉末炭（30mg/L）。研究成果对于延长膜的使用寿命，保证超滤工艺的稳定运行具有重要的意义。