Characteristics of Deep eutectic solvents for CO2 capture with Hydro effects for improvement of mass transfer

Deep eutectic solvents (DESs) prepared by mixing hydrogen bond donors (HBDs) and acceptors (HBAs) are attracting attention to use absorbents for carbon capture, storage, and utilization (CCUS) technology, but their applications in large-scale industries are limited by the scarce research in the field. When DES was used as CO2 absorbent, the use of appropriate HBAs and HBDs is critical for application. In this study, choline chloride (ChCl, as the HBA) was mixed with five different HBDs and diluted to 20 wt% water (W) for improvement of mass transfer, and their CO2 absorption capacities and physicochemical properties were analyzed. Urea (U), ethylene glycol, glycerol, and malic and levulinic acids were used as HBDs due to their various functional groups. ChCl:U:W can be a potential alternative to conventional alkanolamine absorbents for use in CCUS among the studied DESs, as its absorption capacity was superior to those of the other DESs. Increase of surface tension and decrease of density and viscosity were observed by addition of water on all of DESs. Additionally, absorption rate increased via water addition. This study can contribute to the future development of a more efficient CCUS technology using solvent alternatives that are more suitable for future environmental challenges. (c) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

Deep eutectic solvents (DESs) prepared by mixing hydrogen bond donors (HBDs) and acceptors (HBAs) are potential absorbents for carbon capture, storage, and utilization (CCUS) technology. However, their applications in large-scale industries are limited by the lack of research. This study analyzed the CO2 absorption capacities and physicochemical properties of DESs using choline chloride (ChCl) as the HBA mixed with five different HBDs. The results showed that ChCl:U:W could be a potential alternative to conventional alkanolamine absorbents for CCUS, with superior absorption capacity compared to other DESs.