Superior Performance of Mesoporous MOF MIL-100 (Fe) Impregnated with Ionic Liquids for CO₂ Adsorption

Abstract

We present molecular simulations of gases in mesoporous MOF MIL-100(Fe) impregnated with ionic liquids [Bmim+][PF6–] and [Bmim+][Tf2N–]. Adsorption of pure carbon dioxide, methane, nitrogen, and typical mixtures found in flue gases and natural gas are studied. Increases in CO2 adsorption, sitting, and selectivity were investigated to provide an impregnation alternative in a stable material that could be experimentally successful. The presence of ionic liquids, in particular [Bmim+][SCN–], increases CO2 uptake within the pressure range up to 2000 kPa, which is unprecedented for impregnated MOF structures. We found that the impregnation of the mesoporous MOF structure doubles CO2 adsorbed concentration and selectivities (CO2/CH4 and CO2/N2) at ambient temperature and low pressure range (<100 kPa). These results provide evidence that IL impregnation of mesoporous MOFs may render them unique characteristics that are likely to be useful for CO2 capture.