Solvent-responsive covalent organic framework membranes for precise and tunable molecular sieving.

Yang, Hao; Zhang, Haoyuan; Kang, Chengjun; Ji, Chunqing; Shi, Dongchen; Zhao, Dan · Sci Adv · 2024

basic_science · Level V

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Abstract

Membrane-based nanofiltration has the potential to revolutionize the large-scale treatment of organic solvents in various applications. However, the widely used commercial membranes suffer from low permeability, narrow structural tunability, and limited chemical resistance. Here, we report a strategy for fabricating covalent organic framework (COF) membranes with solvent-responsive structural flexibility. The interlayer shifting of these COF membranes in polar organic solvents results in sub-nanopores with high selectivity. High rejection rates (>99%), high permeance (>15 kilogram meter<sup>-2</sup> hour<sup>-1</sup> bar<sup>-1</sup>), and excellent organic solvent resistance of these smart COF membranes are achieved for a diverse array of nanofiltration applications.