Experimental Study of the Solubility of CO2 in Novel Amine Based Deep Eutectic Solvents

Abstract

In this study, we report new measurements of the solubility of carbon dioxide in three types of deep eutectic solvents (DESs), (Choline chloride + Monoethanolamine, ChCl-MEA), (Choline chloride + Diethanolamine, ChCl-DEA) and (Choline chloride + Methyldiethanolamine, ChCl-MDEA), which was determined at three different ChCl:amine molar ratios of 1:6, 1:8 and 1:10. The selected amines represent the primary, secondary and tertiary amines, respectively. The CO2 absorption was conducted with a solvent screening set-up (SSS) and the CO2 loading was measured with an 'Elementar' total organic carbon (TOC) analyzer. The solubility experiments were performed based on the conditions of the absorber in the post-combustion capture process (PCO2 = 15 kPa and T = 40oC). Results revealed that amine-based DESs have absorption capacity that is much higher than both 30wt% aqueous amine solutions and conventional DESs. The solubility of CO2 was found to increase as the molar ratio of the amine in the DES increased. ChCl-MEA absorbed the highest quantity of CO2 while ChCl-MDEA absorbed the least.