Ionic-Liquid-Based CO₂ Capture Systems: Structure, Interaction and Process

The inherent structure tunability, good affinity with CO₂, and nonvolatility of ionic liquids (ILs) drive their exploration and exploitation in CO₂ separation field, and has attracted remarkable interest from both industries and academia. The aim of this Review is to give a detailed overview on the recent advances on IL-based materials, including pure ILs, IL-based solvents, and IL-based membranes for CO₂ capture and separation from the viewpoint of molecule to engineering. The effects of anions, cations and functional groups on CO₂ solubility and selectivity of ILs, as well as the studies on degradability of ILs are reviewed, and the recent developments on functionalized ILs, IL-based solvents, and IL-based membranes are also discussed. CO₂ separation mechanism with IL-based solvents and IL-based membranes are explained by combining molecular simulation and experimental characterization. Taking into consideration of the applications and industrialization, the recent achievements and developments on the transport properties of IL fluids and the process design of IL-based processes are highlighted. Finally, the future research challenges and perspectives of the commercialization of CO₂ capture and separation with IL-based materials are posed.