Higher permeability of carbon dioxide is a necessary requirement for ionic liquid selection for carbon dioxide separation. The Permeability of a gas is a function of both diffusivity and solubility. The results from these measurements have also been used to examine choice of ionic liquids for carbon dioxide separation. Results show that ionic liquids with the best carbon dioxide solubility have slower diffusion coefficient. A comparison of selectivity estimations based on these solubility and diffusivity measurements to membrane permeability measurements performed using a supported ionic liquid membrane support this conclusion.
1. Ying Hou and Ruth Baltus, Ind .Eng. Chem. Res, 46, 8166, 2007