Characterization and comparison of the CO2 absorption performance into aqueous, quasi-aqueous and non-aqueous MEA solutions

Herein, we investigated quasi-aqueous and non-aqueous absorbents based on organic solvents to reduce the amount of water used in wet CO2 capture by amine- and water-based sorbents to <50%. Solvent optimization was performed through screening and vapor pressure tests, and the performances of quasi-aqueous and non-aqueous sorbents prepared using selected organic solvents were evaluated in terms of CO2 absorption rates and equilibrium absorption capacities. All absorbents were subjected to thermogravimetric analyses before and after CO2 absorption to determine their thermal stabilities. Moreover, the prepared absorbents were characterized in terms of reaction heat, sensible heat, and latent heat of evaporation, which were used to determine their regeneration energies. The obtained results revealed that quasi-aqueous/non-aqueous absorbents are superior to conventional water-based ones, exhibiting maximized CO2 absorption and lower regeneration energies.