Effect of Temperature on Gas Transport Properties of Supported Ionic Liquid Membranes

The separations of the CO2/N-2 and CO2/CH4 gas pairs using supported ionic liquid membranes (SILMs) with the immobilized ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate (bmim[BF4]) and 1-butyl-3-methylimidazolium bis(2-ethylhexyl)sulfosuccinate (bmim[doc]) have been compared. The temperature dependences of the gas permeability, diffusion, and solubility coefficients have been obtained experimentally, and the temperature dependence of selectivity has been calculated. It has been found that the selectivity of membranes based on bmim[BF4] slightly decreases with temperature and the separation selectivity of CO2/N-2 and CO2/CH4 systems on the membranes impregnated with bmim[doc] is almost independent of temperature.