A systematic screening methodology towards exploration of ionic liquids for CO2 capture processes

Reducing anthropogenic carbon dioxide emissions into atmosphere is an important and challenging goal as global warming, caused by greenhouse gas emissions, has been recognized as the major driver of climate change. In this context, many researchers have studied the use of ionic liquids (ILs) as solvents for CO2 capture. We propose a systematic, efficient, and quick screening methodology by refining and using COSMO-RS as a predictive thermodynamic model and integrating group contribution based feasibility constraints for viscosity and melting point. The methodology was able to effectively handle different trade-offs and computationally evaluate hundreds of cation and anion combinations to search for optimal ILs. The approach resulted in identification of 10 diverse and uncommon ILs with promising characteristics for CO2 physical absorption/desorption while possessing relatively low viscosity in comparison to more common ILs that have been studied before. Further, these ILs also show significant potential for reducing process energy requirements. The results demonstrate the effectiveness of the proposed methodology for exploring novel IL candidates that have not been assessed previously.