Kinetics study and performance comparison of CO2 separation using aqueous choline-amino acid solutions

The thermodynamic and kinetic properties of CO2 in aqueous choline-amino acids ([Cho][AA]s) are important information to demonstrate their performance. In this study, the apparent kinetic properties of CO2 in the five aqueous [Cho][AA]s, including the liquid-side mass-transfer coefficients, enhancement factor, and reaction rate constant, were systematically studied. Furthermore, a new ‘‘absorption ability’’ (AA) index was proposed, combining the apparent kinetic properties determined in this study and thermodynamic properties determined in our previous study. The CO2 separation performance using aqueous [Cho][AA]s was evaluated based on the AA and CO2 desorption enthalpy values. The results show that 30 wt% aqueous choline-serine is a promising absorbent for CO2 separation, and it is comparable to aqueous monoethanolamine.