新型耐氯耐高温有机硅反渗透膜的结构设计与制备研究

Today, reverse osmosis (RO) membrane technology is the most widely used technology for water purification in a variety of applications. Aromatic polyamide based thin film composite membranes dominate the current RO membrane markets, mainly because of their high salt rejection and high water flux. However, polyamide membranes are quite susceptible to chlorine (which is the most widely used disinfectant), leading to a significant membrane degradation. Moreover, the maximum operating temperature of commercial polyamide membranes is normally below 50 ℃, which severely limits their industrial applications. Therefore, the development of new RO membrane materials, which possess superior chlorine tolerance and high temperature resistance as well as high separation performance, is becoming a key point in the field of RO membrane research. Based on the above, this project is to develop a new generation of RO membrane materials based on organically bridged silica, and carry out research on structural design and preparation of novel organosilica membranes, which is applicable to harsh environments. Robust organically bridged silica materials with high chlorine tolerance and high temperature resistance are designed and fabricated by adjusting the structure of the organic bridging groups. The effects of bridging group structure, sol synthesis and membrane preparation parameters on membrane microstructure are investigated, and the performances on chlorine stability, hydrothermal stability and desalination are evaluated. The theory of membrane formation and the controlling means on the microstructure of membrane, the relationship between membrane microstructure and membrane performance, and the mechanism of chlorine tolerance, high temperature resistance and mass transfer, are further studied on this basis, which provide fundamental knowledge for the development and application of new RO membranes under harsh environments.

反渗透膜技术是目前最为广泛应用的水纯化技术。芳香聚酰胺复合膜因脱盐率高、通量大等优点主导着当前的反渗透膜市场。但聚酰胺膜极易受活性氯（最常用的杀菌剂）攻击而导致膜性能急剧下降。另外，商品聚酰胺膜通常只能在50 ℃以下使用，严重限制了反渗透膜技术的应用领域。因此，开发新的反渗透膜材料，使其同时具备优良的耐氯、耐高温性能以及高分离性能是目前反渗透膜领域研究的重点。基于此，本项目提出将桥联有机硅作为新一代反渗透膜材料，开展适用于苛刻环境下新型有机硅反渗透膜结构设计与制备的研究。通过调控有机桥联基团的结构，设计合成能够耐氯耐高温的有机硅膜材料。研究桥联基团结构、溶胶合成和膜制备工艺对膜微结构的影响，评测膜的耐氯、耐高温性能和反渗透脱盐性能。在此基础上深入探究有机硅膜微结构形成机理与调控方法，膜微结构与膜性能之间的构效关系以及膜的耐氯、耐高温机理和脱盐机理，指导适用于苛刻环境下反渗透膜的开发与应用。

反渗透已成为一种获取洁净淡水的核心技术。芳香聚酰胺复合膜因脱盐率高、通量大等优点主导着当前的反渗透膜市场。但聚酰胺膜极易受活性氯攻击而导致膜性能急剧下降。另外，商品聚酰胺膜通常只能在50℃以下使用，严重限制了反渗透技术的应用领域。本项目开展了适用于苛刻环境下新型桥联有机硅反渗透膜结构设计与制备的研究，主要研究了以下三个方面：（1）调控有机桥联基团的结构，制备出能够耐氯耐高温的有机硅膜材料；（2）桥联基团结构、溶胶合成和膜制备工艺参数对膜微结构的影响，评测膜的耐氯、耐高温性能和反渗透脱盐性能；（3）在此基础上深入探究有机硅膜微结构的调控方法，膜微结构与膜性能之间的构效关系以及膜的传质机理。通过上述研究我们制备出能够耐氯（>500 ppm活性氯）、耐高温（>80℃）且具有较高盐截留率的桥联有机硅反渗透膜，实现在苛刻环境下的反渗透应用。建立了有机硅膜微结构的调控方法以及膜微结构与膜性能之间的构效关系，阐明水分子和盐离子在膜中的传递机理，为适用于苛刻环境下的高性能反渗透膜的开发提供一个有竞争力的新选择。