Study on the effect of operating parameters towards CO₂ absorption behavior of choline chloride – Monoethanolamine deep eutectic solvent and its aqueous solutions

In this study, the effect of absorption pressure and temperature towards the CO₂ absorption capacity and rate of choline chloride - monoethanol amine deep eutectic solvent (ChCl-MEA DES) was evaluated. Water mixing into ChCl-MEA DES was also examined as a method to improve CO₂ absorption behavior. Equilibrium experiments were done in a batch reactor and the data was analyzed using response surface methodology (RSM). Results suggested that the dominant mode of CO₂ absorption by ChCl-MEA DES was physical absorption. The maximum capacity of CO₂ absorption obtained in this study was 0.379 mol-CO₂/mol-DES from absorption at (10 bar, 40 °C) using DES with 50 %v water. Water mixing up to 50 %v was found to nearly double the CO₂ absorption capacity of ChCl-MEA DES compared to neat DES. Study into CO₂ absorption rate by ChCl-MEA DES found that it is mainly influenced positively by pressure and water content, while not significantly influenced by temperature. CO₂ absorption rate of ChCl-MEA DES with 50 %v water was found to be on average twice of that of neat DES. It was also found that water content up to 50 %v does not change the mechanism of CO₂ absorption by ChCl-MEA DES.