As a novel crystalline polymeric material, covalent organic framework (COF) has been paid the most attention by membrane separation researchers all over the world due to its pre-designable, regular pore structures, and reliable chemical stability. However, the fabrication of a homogenous, stable, thin COF layer on the support membrane remains challenging. In this work, the mechanism of electrostatic interaction between amino monomer and support was used to generate a stable and clear interface between the aqueous phase and the organic phase through the interfacial polymerization (IP) process. Specifically, the hydrophilicity and large pore size of polyacrylonitrile (PAN) mixed matrix membrane (MMM) allowed ethidium bromide monomers (EB) from the aqueous phase to penetrate and reach the negatively charged porous surface of the MMM. This assisted the fixation of the EB monomers at the interface with highly electrostatic interaction between the MMM’s surface and the EB monomers. The Tp (1,3,5-triformylphloroglucinol) monomer of organic phase was polymerized with surface entangle EB, resulting in the TpEB COF with very thin, hydrophilic, stable, homogeneously distributed tiny pores, and cationic surface charge. The prepared TpEB COF composite membrane had a water permeability of 32.34 L·m^−2.h^−1.bar⁻¹, highly selective sieving performances for dye molecules of different charges and sizes. This membrane could reject ∼ 99.99 % of anionic dyes like Potassium permanganate (PP), Congo red (CR) and Coomassie brilliant blue G-250 (CBB), meanwhile maintain high solvent permeability for a long time. But for cationic or neutral dyes, the rejection rates mainly depended on their molecular sizes.

共价有机骨架（COF）作为一种新型结晶高分子材料，以其可预先设计、规则的孔结构和可靠的化学稳定性而受到全世界膜分离研究人员的广泛关注。然而，在支撑膜上制造均匀、稳定、薄的 COF 层仍然具有挑战性。在这项工作中，氨基单体和载体之间的静电相互作用机制被用于通过界面聚合（IP）过程在水相和有机相之间产生稳定而清晰的界面。具体来说，聚丙烯腈 (PAN) 混合基质膜 (MMM) 的亲水性和大孔径允许水相中的溴化乙锭单体 (EB) 穿透并到达带负电荷的 MMM 多孔表面。这有助于将 EB 单体固定在界面上，并在 MMM 的表面和 EB 单体之间产生高度静电相互作用。有机相的Tp(1,3,5-三甲酰基间苯三酚)单体与表面纠缠EB聚合，得到具有极薄、亲水、稳定、均匀分布的微孔和阳离子表面电荷的TpEB COF。制备的TpEB COF复合膜透水率为32.34 L·m^-2。h ^-1。bar ^-1，对不同电荷和大小的染料分子的高选择性筛分性能。该膜可滤除高锰酸钾 (PP)、刚果红 (CR) 和考马斯亮蓝 G-250 (CBB) 等 99.99% 的阴离子染料，同时长期保持高溶剂渗透性。但对于阳离子或中性染料，拒收率主要取决于它们的分子大小。