Tuning ionic liquids with imide-based anions for highly efficient CO2 capture through enhanced cooperations

Abstract

Minimizing the release of CO2 into the atmosphere is highly important due to the CO2 concentration dependence of climate change. In this work, highly efficient capture of CO2 is investigated through tuning ionic liquids (ILs) with imide-based anions. It is found that a superior high CO2 capacity (2.21 mol mol−1) be achieved by the imide-based IL with 1,2-cyclohexanedicarboximide anion at 20 °C and 1.0 bar through a combination of chemical and physical absorption. Quantum chemical calculations and spectroscopic analysis suggests that the significant increase in the CO2 capacity is due to the enhanced cooperative interactions between CO2 and three active sites in the anion with electron-donating group. Furthermore, the adsorbed CO2 can be readily stripped from the CO2-saturated IL through slightly heating or bubbling N2, and the IL may be recycled without loss of efficiency.