CO2 separation by supported ionic liquid membranes and prediction of separation performance

Four supported ionic liquid membranes (SILMs) were prepared by fixing ionic liquids (ILs) 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA]), acetate ([BMIM][AC]), trifluoromethanesulfonate ([BMIM][TfO]) and bis ((trifluoromethyl)sulfonyl)imide ([BMIM][NTf2]), respectively, in Polyvinylidene Fluoride (PVDF) membranes and used for the separation of CO2/H-2 and CO2/N-2 gas mixtures. Density function theory (DFT) calculations were performed to predict the complexation energy (E-C) between the ILs and CO2, H-2 and N-2 molecules as well as the gas separation performance of their SILMs. Experimental results indicate that the gas permeation rate of the SILMs increases with increasing temperature. [BMIM][TfO] SILM showed the best separation performance for CO2/H-2 with permselectivity of 16.2 and CO2 permeability of 1966 Barrer at 40 degrees C. [BMIM][AC] SILM showed the best separation efficiency for CO2/N-2 with permselectivity of 21.8 and CO2 permeability of 520 Barrer at 30 degrees C. The separation capacity of SILMs for the CO2/H-2 and CO2/N-2 follows the increasing order of the Ec differences. (C) 2016 Elsevier Ltd. All rights reserved.