调节支撑层表面化学组成定向改进聚酰胺纳滤膜分离层结构

Interfacial polymerization is a common method to prepare nanofiltration membrane. During the interfacial polymerization process, the reaction rate is quite high which results to the very fast and uncontrollable selective layer forming. Recently, the polyamide selective layer with proper structure and chemical composition was constructed by tuning the interfacial polymerization process. However, due to the traditional flux-rejection trade-off, it was difficult to prepare a nanofiltration membrane with both high permeability and high selectivity. As the reaction site of the interfacial polymerization, the formation of polyamide selective layer will be influenced by the surface structure and chemical composition of the substrate. Thus, the aim of this project is to systematically research the influence of the surface chemical composition of the substrate on the interfacial polymerization process, the structure and performance of the polyamide selective layer. In details, a series of ultrafiltration membranes whose surface contained certain functional groups will be designed, prepared and used as the active substrates. The structure and property of the formed polyamide selective layer then will be systematically researched after the interfacial polymerization proceeded on the prepared active substrate. The influence mechanisms of the surface reactivity, the surface charge property and the interaction between the surface and the monomer piperazine of the substrate on the interfacial polymerization process, the structure and performance of the formed polyamide selective layer will be concluded after carefully characterization. According to the findings, the preparation method for nanofiltration membranes with high permeability and high selectivity will finally be established. The findings in this project will provide new insights on the role of substrate on the formation of polyamide rejection layer.

界面聚合是最常规的纳滤膜制备方法，由于其反应速率快，成膜时间短，现有以界面聚合过程调控的方法制备的纳滤膜，其高通量和高选择性往往很难兼顾。由于界面聚合是在支撑层表面发生，其结构和化学组成势必会影响纳滤分离层的结构和性能，为此，本项目拟以调节支撑层表面的化学组成为突破口，以改变界面聚合单体与支撑层表面的相互作用来实现对分离层的调控。具体研究内容包括：制备表面含有不同官能团的超滤膜，实现超滤膜表面化学组成的可控调节；以此为活性支撑层，开展支撑层表面与界面聚合单体间化学反应活性、表面荷电性、表面与水相单体哌嗪之间相互作用力强弱等因素对界面聚合过程和界面聚合所形成的聚酰胺分离层结构、化学组成和分离性能影响的研究，归纳并总结出支撑层表面化学组成对界面聚合过程的影响机理和规律；提出并确立通过调节支撑层表面化学组成来制备高通量和高分离选择性纳滤膜的新策略。

界面聚合是最常用的纳滤膜制备方法，由于其反应速率快，成膜时间短，现有以界面聚合法制备的纳滤膜，其高通量和高选择性往往很难兼顾。传统界面聚合过程发生在支撑层表面，支撑层表面的结构和化学组成会对纳滤分离层的结构和性能产生不可忽视的影响。本项目以调节支撑层表面的化学组成为突破口，研究支撑层表面化学组成对界面聚合过程及所制备聚酰胺分离层结构与性能的影响规律，建立兼具高通量和高分离选择性纳滤膜的制备策略。.经过3年的研究，本项目实现了表面含不同官能团的活性超滤支撑层的可控制备，在此基础上，深入探讨了支撑层表面化学组成对界面聚合过程以及界面聚合所构筑的聚酰胺纳滤分离层结构与性能的影响，最终建立了基于支撑层表面化学组成调控的兼具高通量与高分离选择能力的纳滤膜的制备技术路线。主要体现在：通过两亲共聚物共混、表面水解、表面沉积、表面氨基化、表面氨基化与表面接枝相结合等方式，建立了一系列包括表面具有羟基、羧基、邻苯二酚、氨基、磺酸基、季铵盐、聚醚等官能团的9类活性超滤支撑层的可控制备方法；阐明了支撑层表面反应活性、表面荷电性、表面官能团与水相单体哌嗪间相互作用力强弱等对界面聚合过程以及所形成分离层结构与化学组成的影响机制与影响规律，包括通过表面富集水相单体、改变水相单体向油相的扩散过程、参与界面聚合反应过程等对分离层缺陷、厚度、致密程度、聚酰胺内渗等微结构、分离层与支撑层间的界面结合力、纳滤膜渗透性与选择性等结构与性能产生影响；通过同步优化支撑层表面孔结构与表面氨基含量，建立了可应用于单多价阴离子（氯离子与磺酸根离子）高效分离的高性能纳滤膜制备方法。.项目执行期间，在国内外期刊累计发表论文10篇，其中SCI收录6篇，EI收录2篇，申请国家发明专利4项，其中授权3项。同时培养了一批人才，分别有1位博士与1位硕士获得学位，另为1位博士与2位硕士攻读学位提供了研究课题。