Pervaporation of organic-organic mixtures has shown great potential as a replacement for conventional distillation processes, particularly when dealing with azeotropes and liquids with similar boiling points that are difficult to separate. However, the lack of high-performing membranes that can consistently provide reliable selectivity and high production rates has been a major hurdle in this field. Here, we used an in-situ growth method to prepare two prototypes of imine-linked COFs, i.e., COF-LZU1 and COF-300 membranes for separating azeotropic mixtures of polar/non-polar solvent, i.e., acetone/n-hexane, acetone/cyclohexane and methanol/benzene. The composite membranes comprising a continuous and defect-free COF layer on a ceramic hollow fibre substrate demonstrate high solvent fluxes of acetone and methanol, up to 20.0 and 4.9 kg m⁻²h⁻¹, respectively. The preferential permeation of polar solvents through polar imine-linked nanochannels leads to a high separation factor of the studied mixtures: 30 for acetone/n-hexane, 13.4 for acetone/cyclohexane and 4.3 for methanol/benzene systems. Combined with good stability in solvent systems, our results have proved a technical feasibility of using COF-based membranes for separation of azeotropic solvent mixtures.

有机-有机混合物的全蒸发已显示出替代传统蒸馏工艺的巨大潜力，特别是在处理共沸物和沸点相似且难以分离的液体时。然而，缺乏能够持续提供可靠选择性和高生产率的高性能膜一直是该领域的主要障碍。在这里，我们使用原位生长方法制备了两种亚胺连接的 COF 原型，即 COF-LZU1 和 COF-300 膜，用于分离极性/非极性溶剂（即丙酮/正己烷）的共沸混合物，丙酮/环己烷和甲醇/苯。在陶瓷中空纤维基板上包含连续且无缺陷的 COF 层的复合膜表现出丙酮和甲醇的高溶剂通量，高达 20.0 和 4.9 kg m^-2 h ^-1，分别。极性溶剂通过极性亚胺连接的纳米通道的优先渗透导致所研究混合物的高分离因子：丙酮/正己烷为 30，丙酮/环己烷为 13.4，甲醇/苯系统为 4.3。结合在溶剂系统中的良好稳定性，我们的结果证明了使用基于 COF 的膜分离共沸溶剂混合物的技术可行性。