Gas Solubility in Ionic Liquids: Applications for Carbon Capture and Energy Storage

Ionic liquids (ILs) have been investigated for different aspects and applications. One focus is gas solubility in ILs. Among gases, CO₂ has been studied extensively, driven by the need for carbon capture techniques to combat global warming. Other gases like O₂, NO, or noble gases (Ar, Kr, Xe), which are the focus of this work, have not been widely studied. This is in part due to the difficulty in measuring gases with low solubilities, such as O₂ and Ar.

The main objective of this research is to elucidate different gases dissolution mechanism by studying the phase behavior of the ionic liquids and the gases. Knowledge of the thermodynamic properties are needed to guide ionic liquid structural design for different applications. To this end, the solubilities of O₂, NO, noble gases (Ar, Kr, Xe), and CO₂ were measured in ionic liquids of widely varying sizes and structures. Thermophysical properties including Henry’ law constants, reaction equilibrium constant, standard enthalpy and entropy of absorption/reaction, of those gases in a variety of ionic liquids were characterized.