Preparation of Mixed Matrix Membranes Containing Polyether Block Amide and Silver Nanoparticles to Evaluate the Permeability of CO2, N2, and CH4 Gases

Among the various types of Poly (ether block amides), Pebax1657 shows excellent separation properties for polar or condensable gases such as carbon dioxide in comparison with other light gases. In this research, Pebax1657 as an organic phase and silver nanoparticles as an inorganic phase were considered for preparation of mixed matrix membranes. Moreover, in one side, silver nanoparticles as fillers could enter the polymer chains and enhance the gas permeability by increasing the fractional free volume of membranes. On the other side, partially positively polarized silver nanoparticles beside electron rich parts of PEO segment of the copolymer could increase the CO2 affinity of membranes, which results in increasing the permselectivity of the MMMs for CO2 over CH4 and N2. Also, permeability and selectivity of membranes were studied at different operating temperature and pressures. Moreover, (fabricated) membranes were characterized by FTIR, SEM, and XRD analyses. Obtained results revealed that Ag nanoparticles have decreased the membrane crystallinity and interacted with soft segment of the copolymer, which could enhance transport properties of the polar gases. In addition, the results of gas permeation have shown excellent improvement in permeability and selectivity at temperature of 35 °C and pressure of 10 bar. For the optimum membrane in comparison with the neat one, CO2/CH4 and CO2/N2 selectivities have increased about 112 about 76 % respectively. On the other hand, an increase in the fractional free volume of the neat polymeric matrix has caused to enhance the CO2 permeability up to 141 %.