Chapter 3: CO2 Capture and Separation Using Ionic Liquids
Published:17 Nov 2023
In the past 20 years, ionic liquids (ILs) have been considered as potential alternatives or replacements for aqueous amine solvents in CO2 capture processes. These efforts have undoubtedly yielded much knowledge and new ideas on the molecular design of liquids for CO2 capture and have influenced other technologies such as polymer membranes and solid adsorbents. Despite these great efforts and enthusiasm, there has not been a major project that has scaled-up ILs for CO2 capture much beyond the laboratory stage. In this chapter, the fundamentals of CO2 capture will be discussed along with considerations on the manufacture of solvents for this application. Then, ILs and “reversible ILs” (RevILs) will be introduced along with the various ways they have been applied to CO2 capture, while framing the discussion in the context of the real technical and economic demands of large scale CO2 capture processes, along with the urgency with which such processes must be deployed. While it is unclear whether ILs or RevILs will ultimately meet these demands, it is clear that they have made an indelible impact on the ways scientists and engineers think about the molecular design of solvents for CO2 capture.