Chemical and Physical Ionic Liquids in CO₂ Capture System Using Membrane Vacuum Regeneration

Carbon Capture Utilization and Storage technologies are essential mitigation options to reach net-zero CO₂ emissions. However, this challenge requires the development of sustainable and economic separation technologies. This work presents a novel CO₂ capture technology strategy based on non-dispersive CO₂ absorption and membrane vacuum regeneration (MVR) technology, and employs two imidazolium ionic liquids (ILs), [emim][Ac] and [emim][MS], with different behavior to absorb CO₂. Continuous absorption-desorption experiments were carried out using polypropylene hollow fiber membrane contactors. The results show the highest desorption behavior in the case of [emim][Ac], with a MVR performance efficiency of 92% at 313 K and vacuum pressure of 0.04 bar. On the other hand, the IL [emim][MS] reached an efficiency of 83% under the same conditions. The MVR technology could increase the overall CO₂ capture performance by up to 61% for [emim][Ac] and 21% for [emim][MS], which represents an increase of 26% and 9%, respectively. Moreover, adding 30%vol. demonstrates that the process was only favorable by using the physical IL. The results presented here indicate the interest in membrane vacuum regeneration technology based on chemical ILs, but further techno-economic evaluation is needed to ensure the competitiveness of this novel CO₂ desorption approach for large-scale application.