Exploring Non-aqueous Solutions for CO₂ Capture at Elevated Pressure: An Initial Study for EHA/MOR in DMSO Mixtures

Abstract

Carbon dioxide (CO2) absorption in a non-aqueous solution is a potential technology for reducing greenhouse gas emissions. In this study, a non-aqueous solvent, dimethylsulfoxide (DMSO), was blended with a amines The non-aqueous blended amines absorbents’ CO2 absorption ability was investigated in a high-pressure absorption reactor with a variable absorption pressure (350–1400 kPa) at constant temperature (303.15K). The results showed that 2M EHA in DMSO solution had the highest CO2 loading capacity (molCO2/molamine) when compared with 1M EHA + 1M MOR in DMSO solutions. It was also found that the absorption capacity increased with increasing pressure. The highest CO2 absorption by 2M EHA in DMSO solution was observed at a pressure of 1400 kPa at 303.15 K with 1.2507 molCO2/molamine. The use of non-aqueous blended amine solvents showed no phase separation phenomenon after the CO2 absorption reaction and the formation of carbamate salt was identified through FTIR analysis. 1 M EHA 1M MOR in DMSO has shown a higher initial absorption rate in comparison to 2 M EHA in DMSO which would suggest that the use of a 1M EHA + 1M MOR in DMSO as a non-aqueous solvent could be a promising solution for CO2 capture.