Synthesis and characterization of diethanolamine-impregnated cross-linked polyvinylalcohol/glutaraldehyde membranes for CO2/CH4 separation

In this research, the cross-linking of diethanolamine (DEA) impregnated poly(vinyl alcohol) (PVA) on polytetrafluoroethylene (PTFE) by glutaraldehyde (GA) with different blend compositions (GA/PVA: 0.5, 1, 3, 5, 7 ratio%) was performed in the absence of an acid catalyst and organic solvents in order to avoid any interference in CO2 facilitation reaction with DEA. The fabricated membranes were characterized by differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Furthermore, the effects of cross-linking agent content, feed pressure and composition as well as stability on CO2/CH4 transport properties were investigated in both pure and mixed gas experiments. The cross-linked membranes showed reasonable CO2/CH4 permselectivities in comparison with uncross-linked membranes. The best-yield CO2-selective membranes (DEA-PVA/GA(1 wt%)/PTFE) represented the best CO2/CH4 selectivity of 91.13 and 665 for pure and mixed gas experiments, respectively.