Mixed matrix membranes of Pebax-1657 loaded with 4A zeolite for gaseous separations

• Zeolite 4A loaded Pebax-1657 mixed matrix membranes were synthesized.
• Performance of membranes was studied with pure CO2, CH4, O2 and N2 gases.
• Pebax/4A membranes showed better gas permeation properties to those of Pebax-1657.
• Increasing the zeolite loading enhanced the selectivity CO2/CH4, CO2/N2 and O2/N2.

Mixed matrix membranes (MMMs) made from selective inorganic fillers and polymers have received extensive attention in the field of gas separation. In this work, poly(ether-block-amide), (Pebax)/zeolite 4A MMMs were prepared using ethanol/water as solvent mixture. The concentration of zeolite 4A in membrane was varied from 5 to 30 wt.% of the polymer. The membranes were characterized by SEM, FTIR and XRD to study the morphologies, the effect of zeolite 4A incorporation on intermolecular interactions and degree of crystallinity, respectively. The pure gas permeabilities were recorded at the ambient temperature, using an indigenously built high-pressure gas separation manifold. The permeabilities of Pebax-1657/zeolite 4A membranes were enhanced from 71.4 to 155.7 Barrers for CO2, 2.2–19.6 Barrers for CH4, 5.8–17.9 Barrers O2 and 1.4–12.0 Barrers for N2. The ideal selectivity of 10 wt.% zeolite 4A MMM enhanced from 54.1 to 94.2 for the CO2/N2 gas pair with increase in feed pressure from 5 to 25 kg/cm2, whereas the corresponding values for CO2/CH4 and O2/N2 were found to rise from 26.4 to 41.3 and 4.3 to 4.9, respectively. The Pebax/zeolite 4A membranes thus provide a potentially promising means for separation of CO2/N2, CO2/CH4, and enrichment of O2 and N2 from air.