Ionic liquids: a tool for CO2 capture and reduced emission

The anthropogenic carbon dioxide (CO2) emission into the atmosphere causes environmental concern that leads to drastic climate change due to global warming. The capture of CO2 from flue gases and utilization into value-added products is a viable method for reducing CO2 emissions. Amine-based solvents have been widely employed for the separation of CO2 from the postcombustion process. However, they show several problems that lead to looking for alternative compounds for efficient CO2 capture. In the recent past, new generation environmental benign solvents such as room temperature ionic liquids (ILs) have shown excellent performance for CO2 capture and identified as potential candidates for efficient separation of CO2. The unique characteristics and tunable physicochemical properties of ILs have been explored for preparing different kinds of cost-effective materials or mixtures, which enables better performance in CO2 capture. The present work discusses the critical role of ILs in separating CO2 using various techniques such as absorption, adsorption, and membrane separation technology. Further, the regeneration methods for the desorption of CO2 from ILs have been discussed. Finally, the study gives the future directions for designing ILs to capture CO2 from flue gases and sweetening of gases efficiently.