Acetate based Supported Ionic Liquid Membranes (SILMs) for CO2 separation: Influence of the temperature

Supported Ionic Liquid Membranes (SILMs) were prepared with the acetate based Room Temperature Ionic Liquids (RTILs) 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]), 1-butyl-3-methylimidazolium acetate ([Bmim][Ac]) and the monomer vinylbenzyl trimethylammonium acetate ([Vbtma][Ac]) in order to perform the selective separation of carbon dioxide (CO2) from nitrogen (N-2). The RTILs were supported in a polyvinylidene fluoride porous membrane and permeation experiments were performed in the temperature range 298-333 K. Gas permeability increases with temperature while an increase in temperature leads to a decrease in the CO2/N-2 selectivity for all the studied RTILs. CO2 solubility was evaluated in the range 298-333 K and atmospheric pressure using thermogravimetric techniques. Diffusion coefficients were calculated based on the solution-diffusion theory using gas permeability and solubility data. The temperature influence on the gas permeability, solubility and diffusivity are well described in terms of the Arrhenius-van't Hoff exponential relationships. (C) 2013 Elsevier B.V. All rights reserved