CO2 capture by alcohol ammonia based deep eutectic solvents with different water content

Abstract

The existing CO _2 absorption by deep eutectic solvents is limited by the unavoidable water absorption problem during use. In this study, we prepared three deep eutectic solvents with different alcohol aminations and added different water contents to discuss the effect of water content on the absorption of carbon dioxide by deep eutectic solvents. All deep eutectic solvents have a low melting point at room temperature as a liquid and have high thermal stability, where the choline chloride-diethanolamine deep eutectic solvents have a high viscosity. Anhydrous choline chloride-monoethanolamine deep eutectic solvents have the largest CO _2 absorption, reaching 0.2715 g g ^−1 , and the absorption of CO _2 by anhydrous choline chloride-N-methyldiethanolamine deep eutectic solvents is only 0.0611 g g ^−1 . Water content inhibited the absorption of CO _2 in primary amine and secondary amine systems, whereas it enhanced the absorption of CO _2 in tertiary amine systems, which was related to the reaction process of deep eutectic solvent and CO _2 .

Keywords

• deep eutectic solvents
• water content
• CO2 capture
• absorption
• alcohol ammonia solution