Organic solvents induced enhancement of phase-splitting behaviors and CO2 absorption performance in biphasic absorbent

Reducing the rich phase ratio is a key issue for developing the biphasic absorbents. In this study, it is found that the hydrophobic solvents (sulfolane and N, N-dimethylformamide) are beneficial for reducing rich phase volume, while hydrophilic solvents (n-propanol, Polyethylene glycol) inhibit the phase splitting. Sulfolane is the optimal solvent, wherein, the rich phase ratio is greatly reduced from 79 % to 37 %. The CO 2 absorption capacity in the rich phase increases from 2.50 M to 4.25 M. The kinetic studies show that the total mass transfer coefficient is increased by 1.96 times with sulfolane addition. The regeneration energy consumption of the developed absorbent is only 1.85 GJ/t-CO 2 , which is 53.6 % less than MEA. The results can provide a theoretical reference for developing high-performing biphasic absorbents.