Ultramicroporous Covalent Organic Framework Nanosheets with Functionality Pair for Membrane C<sub>2</sub>H<sub>2</sub>/C<sub>2</sub>H<sub>4</sub> Separation
Jialu Li, Zeliang Cheng, Ziyang Wang, Junchao Dong, Haicheng Jiang, Wenjian Wang, Xiaoqin Zou, Guangshan Zhu
Abstract
Abstract Gas separation efficiency of covalent organic framework (COF) membrane can be greatly elevated through precise functionalization. A pair‐functionalized COF membrane of 1,3,5‐triformylphloroglucinol (TP) and isoquinoline‐5,8‐diamine (IQD) monomers in two and three nodes is designed and synthesized. TP‐IQD is crystallized in a two‐dimensional structure with a pore size of 6.5 Å and a surface area of 289 m 2 g −1 . This COF possesses N−O paired groups which cooperatively interact with C 2 H 2 instead of C 2 H 4 . TP‐IQD nanosheets of ≈10 μm in width and ≈4 nm in thickness are prepared by mechanical exfoliation; they are further processed with 6FDA‐ODA polymer into a hybrid membrane. High porosity and functionality pair of TP‐IQD offer the membrane with significantly increased C 2 H 2 permeability and C 2 H 2 /C 2 H 4 selectivity which are 160 % and 430 % higher of pure 6FDA‐ODA. The boosted performance demonstrates high efficiency of the pair‐functionality strategy for the synthesis of separation‐led COFs.