Photo-tailored heterocrystalline covalent organic framework membranes for organics separation.

Yuan, Jinqiu; You, Xinda; Khan, Niaz Ali; Li, Runlai; Zhang, Runnan; Shen, Jianliang; Cao, Li; Long, Mengying et al. · Nat Commun · 2022

basic_science · Level V

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Abstract

Organics separation for purifying and recycling environment-detrimental solvents is essential to sustainable chemical industries. Covalent organic framework (COF) membranes hold great promise in affording precise and fast organics separation. Nonetheless, how to well coordinate facile processing-high crystalline structure-high separation performance remains a critical issue and a grand challenge. Herein, we propose a concept of heterocrystalline membrane which comprises high-crystalline regions and low-crystalline regions. The heterocrystalline COF membranes are fabricated by a two-step procedure, i.e., dark reaction for the construction of high-crystalline regions followed by photo reaction for the construction of low-crystalline regions, thus linking the high-crystalline regions tightly and flexibly, blocking the defect in high-crystalline regions. Accordingly, the COF membrane exhibits sharp molecular sieving properties with high organic solvent permeance up to 44-times higher than the state-of-the-art membranes.