Fabrication of a flexible hydrogen-bonded organic framework based mixed matrix membrane for hydrogen separation

Abstract

Hydrogen-bonded Organic Frameworks (HOFs), consisting of H-bonds and strong π-π interaction, are novel materials with ordered and flexible porous frameworks. With permanent porosity, HOFs are considered as a promising material for large-scale preparation of gas separation membranes owing to their superior stability. Herein, we report a novel HOF-based Mixed-Matrix Membrane (MMM) termed HOF-30@PI by blending HOF-30 crystals with PolyImide (PI) for hydrogen separation. The added amount of HOF-30 has a crucial effect on gas separation performance. A HOF-30@PI MMM with 10 wt% HOF-30 exhibits a high hydrogen permeability of 428.1 barrer and H2/CH4 separation factor of 61.7. Owing to good compatibility and the proper pore size of HOF-30 with 4 Å, the HOF-30@PI MMM shows excellent stability and has no obvious separation performance degradation after a 240 h testing. Interestingly, HOF-30@PI MMM has a certain response on pressure because of its flexibility due to hydrogen bonds. Therefore, the usage of HOFs as porous fillers in MMM develops a novel way toward the tailored synthesis of advanced composite membrane materials for gas separation.