磁性诱导强制共价有机框架（COFs）表面偏析构筑高性能纳滤膜及膜过程强化

Low permeation flux and membrane fouling are bottlenecks restricting the development of nanofiltration membranes. In view of the trade-off effect between permeability and selectivity of nanofiltration membrane and membrane fouling in separation process, this project aims to construct efficient water molecule transport channels and anti-fouling membrane surfaces. The membranes were designed and fabricated by forced covalent organic framworks surface segregation in magnetic-field. Based on the precise regulation of filling particle surface and internal structure (chemical composition, pore structure, spatial dimension, particle size, etc.) of the membrane, the physical and chemical microenvironments including chain spacing, free volume, channel size was changed to improve the flux of nanofiltration membranes. Inspired by the hydrophilic antifouling surface in cell membrane, membranes were prepared through forced zwitterionic COFs surface segregation for good antifouling. The methods of precise control multi-level water channels and membrane surface structure are expected to establish which could strength the membrane process via high efficiency water channel and anti-fouling membrane surface.

低渗透通量和膜污染是制约纳滤膜发展的瓶颈。本项目针对纳滤膜材料渗透性与选择性相互制约及分离过程中的膜污染问题，以制备高通量、抗污染纳滤膜为目标，围绕纳滤膜目前面临的共性关键问题，以构筑高效水分子传递通道和抗污染膜表面为策略，从膜的填充颗粒表面和内部结构（化学组成、孔结构、空间维度、粒度等）精密调控出发，磁性诱导下，强制磁性共价有机框架(COFs)颗粒在膜表面偏析，调节膜内亲疏性、高分链间距、自由体积/通道尺寸等物理化学微环境，提高纳滤膜通量；受自然界细胞膜低污染表面调控策略启发，强制两性离子型COFs在膜表面偏析，提高纳滤膜抗污染性能，以期建立膜内多级水通道结构及膜表面结构的精密调控方法，实现高效水通道、膜表面抗污染协同强化膜过程。

低渗透通量和膜污染是制约纳滤膜发展的瓶颈。针对纳滤膜水通量与选择性相互制约的“trade-off”效应现象，本项目通过界面聚合在纳滤膜中引入共价有机框架（COFs）以及金属有机框架(MOFs)纳米材料，在膜内构建高效水分子传质通道。针对膜污染问题，本项目通过两性离子改性填充材料表面、膜表面接枝两性离子聚合物等策略，改善纳滤膜表面的亲水性，抑制了污染物在膜表面的堆积、吸附，提高了纳滤膜抗污染性能。然而，采用上述方法构建的防污膜表面在长周期运行后，不可避免地会出现污染物吸附、孔道堵塞，进而导致防污能力下降，运行成本升高。光控超分子可逆体系为创制可再生抗污染纳滤膜提供了新思路。基于β-CD与偶氮化合物光控超分子可逆体系，我们设计、制备了光控可再生抗污染纳滤膜。综上所述，本项目从纳米尺度调控膜材料的水通道尺寸，借助两性离子调控膜表面化学环境，对所制备膜材料的通量、选择性、抗污染性能进行了系统考察，为制备高性能纳滤膜提供了策略和途径。