Enhancing hydrogen gas separation performance of thin film composite membrane through facilely blended polyvinyl alcohol and PEBAX

Abstract

Polymeric membranes offer economic separation processes but are less explored for H2 separation application. This work aims to unveil the H2 separation potential of polymeric membrane by developing PVA-based reverse selective composite membrane. CO2-selective PEBAX was blended at different PVA:PEBAX ratio. The effect of PEBAX blending on membrane morphology, crystallinity and gas separation behavior was studied. Incorporation of PEBAX at <50 wt% resulted in composite with improved CO2 permeability but selectivity loss. Blending of >60 wt% PEBAX enhanced both permeance and selectivity of the resulted composite as the host matrix was dominated by this PEO containing material thus greatly enhancing polymer chain mobility and promoting CO2-solubility. The best composite which contains 60 wt% PEBAX exhibited CO2 permeability of 20.0 Barrer and CO2/H2 selectivity of 7.6. This performance surpasses the Robeson's boundary and unleashes the potential of tailoring the properties of polymeric nanocomposite membrane for H2 separation application through facile PVA/PEBAX blending.