(398ag) Molecular Insights on the Reverse-Selectivity Potential of Room Temperature Ionic Liquid Membranes

Recently, room temperature ionic liquid (RTIL) membranes have attracted attention due to their excellent performance for gas separation applications. In this work, the reverse-selective potential of RTIL membranes has been investigated using molecular dynamics simulation. Since the kinetic diameter of propane (C₃H₈; 4.30 Å) is larger than that of nitrogen (N₂; 3.64 Å) and methane (CH₄; 3.80 Å), C₃H₈/N₂ and C₃H₈/CH₄ separations are good indicators of reverse-selectivity. Six imidazolium-based ionic liquids were selected for this study. The pure gas diffusivity, solubility, and permeance were determined for the RTIL membranes and a good agreement was observed for these calculated transport properties with the experimental data. In addition, based on the theoretical findings in this study, gas transport through the RTIL membranes is found to be dominated by solubility rather than diffusivity, which is a requirement for the reverse-selective membranes.