饮用水净化过程中膜材料与膜工艺的稳定性及安全性机理研究

Taking membrane material stability and membrane filtration safety as the objective, this research conjunctively studies the safety and stability of membrane technique applied in drinking water treatment, aiming at the problems of membrane property changes and water quality safety caused by the precipitation of reagents in membrane and the utilization of chemicals in treatment processes during applying organic membrane materials in drinking water production process. On the basis of giving consideration to polymer properties, taking advantage of optical and electrical methods for modern material analyses, this research quantitatively analyzes the precipitation laws of pore-foaming agents, solvents and additives, comprehensively evaluates the potential impact of reagent precipitation during membrane separation on drinking water safety, and thoroughly explores the effect of reagent precipitation on membrane microstructure and filtration performance. Besides, this research studies the relationship between the usages of coagulants, cleaning agents and disinfectors in water treatment process and the performances of membrane materials combining with coagulation membrane filtration process, and turns to the effective control of membrane property damages produced by process mismatching. By adopting system dynamics approach, this research establishes the evaluation system of membrane material service lifespan in drinking water treatment, thus provides scientific foundation for the cost accounting and evaluation of membrane equipments. As a whole, this research can scientifically interpret the key factors resulting in membrane property changes in drinking water treatment for achieving the safe, stable and effective operation of membrane filtration process, and offer the theoretical foundation to improve the technical level of membrane technique applied in drinking water treatment in China.

本研究针对有机膜材料在饮用水生产过程中，因膜体中试剂析出和处理工艺中使用药品导致的膜性能变化和水质安全问题，以追求膜材料稳定和膜过滤安全为目标，二维一体的研究膜法饮用水处理工艺的安全性和稳定性。在兼顾聚合物性质的基础之上，利用光学、电学等现代材料分析手段，定量分析致孔剂、溶剂以及添加剂等试剂的析出规律，科学评价膜分离过程中试剂析出对饮用水安全的影响程度，精确剖析试剂析出对膜结构和性能的影响因素；结合混凝-膜过滤工艺研究混凝剂、清洗剂、消毒剂在水处理过程中与膜材料的性能影响关系，有效控制因工艺不匹配而造成的对膜材料性能损伤；采用系统动力学（SD）手段，建立饮用水处理中膜材料使用寿命评价体系，为膜装备成本核算评估提供科学支持。本项目研究可科学诠释导致饮用水处理中膜性能变化的关键因素，以实现膜过滤的安全、稳定、高效运行，为提升我国膜法饮用水处理技术水平提供理论依据。

本课题围绕膜法水处理工艺中有机膜材料的安全性和稳定性问题，从材料化学组成、物理结构、分离传质机理、协同工艺影响等多个层面入手，深入探讨了长期运行过程中分离膜性能的动态演化规律及其影响因素。针对分离膜材料的稳定性问题，首先从膜中残留致孔剂、亲水改性剂等添加剂的析出行为入手，揭示了添加剂化学结构、亲水水合作用对膜孔尺寸及膜分离性能的影响机制；同时，针对实际水处理过程中存在的混凝、化学清洗、膜消毒等协同工艺，着重考察了化学药剂投加对聚合物分子结构以及膜孔微观结构的影响机制，从而进一步在膜法水处理工艺、膜面物化特性、膜孔介观结构、膜分离性能间建立了有效联系。此外，针对化学氧化、物理反洗、添加流失等因素所导致的使用过程中膜材料孔径尺寸增大、分离性能降低等现象，本项目还从微观和介观角度入手，深入探讨了膜孔平均尺寸、孔径分布、分配系数、水合半径、自由体积等参数在不同污染物分离过程中的作用机理，并由此建立了基于膜污染行为控制的膜分离性能调控方法和老化膜快速修复方法。通过本项目开展，有望为进一步保证和提高膜出水水质提供理论支持。