Abstract Nanofiltration is a promising technology towards desalination and water purification. However, the pursuit for separation efficiency was hampered by the thick and less controllable selective layer. Herein, the ultrathin composite membranes with enhanced nanofiltration (NF) performance were achieved by interfacial polymerization mediated by polydopamine (PDA)-covalent organic framework (COF) interlayer. The hybrid interlayer with exceptional surface hydrophilicity and high porosity controlled the adsorption/diffusion of amine monomers during the interfacial polymerization process and generated an ultrathin and dense polyamide (PA) layer, which was immensely reduced from 79 nm to 11 nm in thickness. The PA/PDA-COF/PAN nanofiltration membrane exhibited desirable desalination ratio (93.4% for Na2SO4) and dye rejection (94.5% for Orange GII), along with outstanding water permeation flux of 207.07 L m−2 h−1 MPa−1, 3 times higher than that of commercial NF membranes with similar solute rejection. Moreover, the hybrid interlayer significantly strengthened the interfacial interaction between the PA layer and the polyacrylonitrile (PAN) support, rendering the composite membrane with superior structural stability. The proposed strategy provided novel insight into the rational design of multifunctional interlayer to manipulate interfacial polymerization for high-performance PA membranes.

中文翻译：

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具有聚多巴胺-共价有机骨架夹层的超薄纳滤膜可增强渗透性和结构稳定性

摘要 纳滤是一种很有前途的海水淡化和水净化技术。然而，对分离效率的追求受到了厚且不易控制的选择性层的阻碍。在此，通过聚多巴胺（PDA）-共价有机骨架（COF）夹层介导的界面聚合实现了具有增强纳滤（NF）性能的超薄复合膜。具有优异表面亲水性和高孔隙率的混合中间层在界面聚合过程中控制了胺单体的吸附/扩散，并产生了超薄致密的聚酰胺 (PA) 层，其厚度从 79 nm 大大减少到 11 nm。PA/PDA-COF/PAN 纳滤膜表现出理想的脱盐率（Na2SO4 为 93.4%）和染料截留率（Orange GII 为 94.5%），以及 207.07 L m-2 h-1 MPa-1 的出色水渗透通量，是具有类似溶质截留率的商用 NF 膜的 3 倍。此外，混合夹层显着增强了 PA 层与聚丙烯腈 (PAN) 载体之间的界面相互作用，使复合膜具有优异的结构稳定性。所提出的策略为多功能夹层的合理设计以操纵高性能 PA 膜的界面聚合提供了新的见解。使复合膜具有优异的结构稳定性。所提出的策略为多功能夹层的合理设计以操纵高性能 PA 膜的界面聚合提供了新的见解。使复合膜具有优异的结构稳定性。所提出的策略为多功能夹层的合理设计以操纵高性能 PA 膜的界面聚合提供了新的见解。