CO2/CH4 separation by high performance co-casted ZIF-8/Pebax 1657/PES mixed matrix membrane

Abstract

ZIF-8 particles were synthesized at different temperatures. The resulted ZIF-8 particles were characterized by particle size analyzer, SEM, XRD, N2 adsorption and BET tests. ZIF-8/Pebax 1657 mixed matrix membranes (MMMs) were prepared by co-casting. A thin (1.6–7.1 μm thickness) and defect free selective top layer of ZIF-8/Pebax 1657 was formed on top of polyethersulfone (PES) sub layer. The resulted MMMs with thin selective layer showed significant improvement in CO2 permeability and CO2/CH4 selectivity in both pure and mixed gas permeation tests compared with pure Pebax 1657 membrane. Remarkable permeability of 758 Barrer with CO2/CH4 selectivity of 16.1 was observed for the MMM synthesized by smallest ZIF-8 particles (fabricated in 60 °C) with about 2 μm thickness of selective layer. The synthesized MMMs in this study showed competitive CO2/CH4 separation performance compared with reported state of the art Pebax based membranes in pure gas permeation tests.