A gradient viscosity model for estimating CO2 permeability of amino acid ionic liquid-based facilitated transport membrane

Abstract Amino acid ionic liquids (AAILs) are used as a CO2 carrier in facilitated transport membranes (FTM) due to their high CO2 permselectivity. However, estimating the membrane performance of these FTMs is difficult because the viscosity of the AAIL increases with the CO2 absorption. Therefore, potential models were investigated to accurately estimate the CO2 permeability of an AAIL-based FTM. Herein, models were constructed to estimate the CO2 absorption amount and viscosity of the AAIL through simulations at various CO2 partial pressures and temperatures. Furthermore, the CO2 permeability of the AAIL-based FTM at various conditions were estimated based on the models and compared to the experimental data. Consequently, we reported a model that expressed the viscosity gradient of the AAIL in the FTM by dividing the membrane into small intervals to estimate the CO2 permeability with high accuracy.