Preparation of ZIF-8 membranes for H2/CO2 separation by gel-assisted in-situ growth

Hydrogen (H 2 ) is a key feedstock for clean energy, and efficient separation of H 2 /CO 2 is an important link. To solve classic ZIF-8 membrane difficulties, such as long preparation times and weak binding force between crystals and supports, this work used an innovative gel-assisted in-situ growing approach. Specifically, a zinc-based gel was placed onto the PSf support and thermally activated, resulting in the creation of an ultra-thin dense membrane with a thickness of about 100 nm. The effects of reaction time and 2-MIM concentration on membrane performance were thoroughly examined. The results showed that the 0.8-ZIF-8-40 membrane had the best separation performance. The resulting 0.8-ZIF-8-40 membrane exhibited an H 2 permeance of 2200 GPU and an H 2 /CO 2 selectivity of 33, surpassing the Robeson upper bound (2008). Furthermore, the membrane maintained good separation performance after 60 h of continuous operation.