Polymer supported ZIF-8 membranes by conversion of sputtered zinc oxide layers

Abstract

ZIF-8 composite membranes were synthesized at room temperature from aqueous solution by a double-zinc-source method on polyacrylonitrile (PAN) porous supports. The support was coated with zinc oxide (ZnO) by magnetron sputtering prior to ZIF-8 growth to improve the nucleation as well as the adhesion between the ZIF-8 layer and support. By this method, we were able to grow a continuous, dense, very thin (900 nm) and defect free ZIF-8 layer on a polymeric support. The developed ZIF-8 membranes had a gas permeance of 1.23 × 10 -7 mol m -2 sec -1 Pa -1 for hydrogen and a selectivity of 26 for hydrogen/propane gases which is 5 times higher than the Knudsen selectivity. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were done to characterize the membranes.