Gas separation properties of supported liquid membranes prepared with unconventional ionic liquids

Abstract

In this work first supported liquid membranes (SLM) were prepared with twelve different types of ionic liquids (ILs). Then the permeability for H 2, N 2, CO 2 and CH 4 gases and the selectivity of the membranes were investigated in a self-designed membrane module. The effect of CO 2 was also studied by measuring decrease in H 2 permeability after the permeation of CO 2. Membranes with the best gas separation effectiveness were selected and the transmembrane pressure and temperature dependence of their permeability was determined applying H 2. Furthermore their stability was investigated by measuring the change in their H 2 and N 2 permeability and H 2/N 2 selectivity as a function of time. It was found that the ILs that did not destroy the supporting membrane material, hence were suitable for membrane preparation showed adequate permeabilities and were highly selective for CO 2 and CH 4. It was also shown that CO 2 had an effect on each supported ionic liquid membranes (SILMs). However, the extent of the effect was slightly different in all cases. Experiments regarding the temperature and pressure dependence of membrane permeability indicated that the permeability decreased with the increase in pressure and increased with the increase in temperature. It can be stated that SILMs have adequate permeabilities, high selectivities and enhanced stability and therefore they could be successfully used in gas separation processes.