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 (N2). 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/N2 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–vanʹt Hoff exponential relationships.