Covalent organic frameworks based membranes for separation of azeotropic solvent mixtures by pervaporation
Covalent organic frameworks based membranes for separation of azeotropic solvent mixtures by pervaporation
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DOI：
10.1016/j.memsci.2023.121679
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发表时间：
2023-04
影响因子：
9.5
通讯作者：
Kornkamol Banjerdteerakul;Hao Peng;Kang Li
中科院分区：
文献类型：
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作者：
Kornkamol Banjerdteerakul;Hao Peng;Kang Li
有机-有机混合物的渗透蒸发已显示出替代传统蒸馏过程的巨大潜力，特别是在处理沸点相似且难以分离的共沸物和液体时。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。本文采用原位生长的方法制备了两种亚胺连接的COFs原型膜，即COF-LZU1和COF-300膜，用于分离极性/非极性溶剂共沸混合物，即丙酮/正己烷、丙酮/环己烷和甲醇/苯。该复合膜在陶瓷中空纤维基底上由连续无缺陷的COF层组成，具有丙酮和甲醇的高溶剂通量，分别高达20.0和4.9 kg m - 2h - 1。极性溶剂通过极性亚胺连接纳米通道的优先渗透导致了所研究混合物的高分离系数：丙酮/正己烷为30，丙酮/环己烷为13.4，甲醇/苯为4.3。结合在溶剂体系中良好的稳定性，我们的结果证明了使用cof基膜分离共沸溶剂混合物的技术可行性。
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.