磺化聚酰胺复合纳滤膜的分子设计、过程调控及分离机理研究

荷电纳滤膜由于其特殊的孔径筛分与电荷效应，使得其在化工、环保、食品、医药等诸多领域具有很广阔的应用前景。目前，商用纳滤膜主要通过界面聚合法制备，其中的聚酰胺复合脱盐层大都局限在以聚哌嗪酰胺为分子结构的体系内，选择面相对较窄。本项目以开发出可与聚哌嗪酰胺分离性能相比拟的膜材料为目标，提出新型磺化分离膜的概念，力图从源头拓宽膜材料分子结构的可选择性。以分子设计为切入点，通过功能需求调控主链形式；进而以膜材料制备为基础，通过工艺过程优化获取最佳参数条件；最后，以宏观性能的需求为标尺评估膜材料分离性能等重要指标，从而给出材料本身构效关系的耦合反馈。全过程辅以原子、微观及介观尺度的模拟，实现分子亲核性的数值化分析、界面聚合过程本体模型的构建并揭示“溶质-聚合物-水”之间的相互作用机理。本项目的开展，可以为新型纳滤膜的开发及工业应用提供理论基础与技术支撑。

Due to its special pore and charge effects, nanofiltration membrane has a great potential for use in chemical engineering, environmental, food, pharmaceuticals industry, etc. The state-of-the-art nanofiltration membranes are commonly fabricated via interfacial polymerization (IP), of which are still limited in the polypiperazine-amide (PA-PIP)-based thin film composite (TFC). Aiming to develop novel nanofiltration membrane materials with comparative separation performance, a sulfonated polyamide (SPA) concept is put forward so as to expand the choices of precursors in aqueous solution. Initially, the current project is to start with the molecular design, with the main-chain type purposefully adjusted in considering the processability, solubility, diffusion ability and so forth. Furthermore, the membranes are then fabricated, and the optimum parameters are obtained during the IP processes. Finally, the separation performances of the TFC membranes are systematically evaluated, utilizing the real-state application requirement as a reference. Notably, the internal “structure-performance” relationship is simultaneously studied with the aid of multi-scale simulation methods, i.e., sites reactivity on a molecule is obtained on an atomic scale, the separation mechanism between membrane chemistry and pollutants is investigated by molecular dynamics, and the IP model with regard to the structural evolution is fulfilled on a mesoscopic scale. It is anticipated that, the new understandings brought by this type of SPA nanofiltration membrane will significantly promote the development of the pressure-driven membrane research field to the industrial applications.