基于“可控”表界面工程的聚合物纳滤膜

Polymer Nanofiltration Membranes via Controlled Surface/Interface Engineering

复合纳滤膜凭借其效率高与能耗低的特点在分离膜领域占据着越来越重要的地位. 但其制备所面临的最大挑战在于如何实现选择性皮层构建过程及结构性能的有效调控.通过"可控"的表界面工程可以实现对界面性质及界面反应速率的调控,从而实现复合纳滤膜的可控制备和性能提升.因此,我们提出通过""可控"聚合-界面沉积"构建选择性皮层以实现复合纳滤膜分离层的创新制备和多功能化、基于"基膜-单体溶液界面构建"调控界面聚合以获得更薄分离层和更优异的纳滤性能.本文总结和评述了基于"可控"表界面工程的聚合物纳滤膜的重要进展,分析了该领域的未来研究方向,旨在为高性能复合纳滤膜的可控制备提供系统的方法学及理论支持.

Nanofiltration membranes occupy a crucial position in membrane technology due to their superiority of high separation efficiency and low energy cost, which are therefore widely applied in the field of water treatment, food and medicine, membrane bioreactor and petro chemistry. Most nanofiltration membranes are made from polymeric materials with composite structure containing a thin selective layer and a porous support layer. As the key of this structure, the selective layer can be fabricated via various methods such as interfacial polymerization, layer-by-layer assembly, surface coating and graft polymerization followed with crosslinking. However, it still remains a big challenge to precisely control the skin layer structures during interfacial polymerization process ascribed to its very fast reaction. We demonstrate that the interfacial property and the interfacial reactions can be well tuned via controlled surface/interface engineering, thus to control the fabrication and performance of the composite nanofiltration membranes. This review is aimed to summarize the most recent advances on polymeric composite nanofiltration membranes based on controlled surface/interface engineering mainly conducted in our group. On one hand, a tunable polymerization-deposition strategy is proposed to realize novel or functional selective layer. In these cases, dopamine and derivative polyphenol are employed to fabricate the selective layer with self-polymerization and deposition process tuned by additives, oxidant and contra-diffusion operation. Novel nanofiltration membranes with photocatalytic function are further achieved owing to the reactive moieties in the co-deposition layer. On the other hand, an interfacial property tailoring interfacial polymerization strategy is proved to obtain ultrathin and high-performance nanofiltration membranes. An intermediate layer is fabricated prior to traditional interfacial polymerization with excellent hydrophilicity and uniform structure, which help to homogenize the monomer concentration on substrate surface and control the release of monomers to achieve ultrathin polyamide layer. We believe that these advances will provide reliable methodological and theoretical foundation for the controllable fabrication of high performance composite nanofiltration membranes. Moreover, the challenges remained in this area are also presented, such as details of chemical reactions, reaction-structure-function relationship, optimization of methodology and development of basic theory, to point out the future research direction with the aim to push forward the studies in this area.