Ionic Liquid Design for Enhanced Carbon Dioxide Capture – A Computer Aided Molecular Design Approach

Greenhouse gases emission is known as the main factor of climate change, and carbon dioxide (CO2) makes up vast majority of them. Carbon capture and storage (CCS) is a vital technology to mitigate industrial CO2 emissions, which is mainly generated in power plants. Currently, post-combustion capture based on aqueous amine scrubbing is considered as the most suitable technology for CO2 capture. However, the use of amine for CO2 capture has some disadvantages, such as high energy required for solvent regeneration, high solvent loss, and degradation of solvent. Recently, ionic liquids (ILs) are considered as potential alternative, because they have negligible vapour pressure, and high thermal stability. In addition, through matching of cations and anions, ILs provide a flexibility to tune their properties. However, due to vast number of potential ILs, time and expense required to obtain the optimal ILs for CO2 absorption through experimentation is unaffordable. This work presents a Computer-Aided Molecular Design (CAMD) approach for the design and selection of optimal ILs specifically for the purpose of CO2 capture. The approach utilises group contribution method to estimate the thermophyscial properties of ILs, by considering the structural constraints and allowed combination of cations and anions. Predicted properties of the potential candidates are in good agreement of experimentally measured properties.