Understanding the fundamental interaction mechanism of hazardous gases and imidazolium based ionic liquids for efficient gas adsorption

In this study we present an investigation on the adsorption mechanism of hazardous gases (CO, CO2, H2S and SO2) on the ILs having the 1-Ethyl-3-methylimidazolium cation (C2mim+) and halide anions (Cl−, Br−, I− and BF4−), employing the first principles-based density functional theory (DFT). Adsorption energy data reveals that the C2mim Cl and C2mim Br ILs demonstrate a relatively higher adsorption energy value for all the gasses. Strong interactions between gases and ILs can be identified by ν(C2-H) mode of cation, 786 cm−1 and 1390 cm−1 vibrational bands of CO2 and SO2 gases, respectively, as marker bands. Electronic structure calculation and AIM analysis confirm that all the gas molecules are more favorable to interact with the cation. Our present findings may be the prototype investigation to govern the experimental realization for the adsorption of such dangerous gases on the imidazolium-based ILs.