Low energy-consuming CO2 capture by phase change absorbents of amine/alcohol/H2O.

• Screening and evaluation of amine/alcohol/H 2 O absorbents were conducted. • The difference of ΔGsol in alcohol and in water confirms phase change behavior. • Alcohol could not only trigger phase change but also facilitate CO 2 absorption. Phase change absorbents have recently drawn increasing attention due to the potential of for low energy-consuming CO 2 capture. When forming two phases after CO 2 absorption, only the CO 2 -rich phase is heated in the desorption process thus reducing the sensible heat. In this work, five amine and three alcohol blends were used to investigate their phase change behavior after reacting with CO 2. Phase separation could easily occur for DETA/alcohol/water combinations after CO 2 absorption, which was confirmed by the large difference of the solvation free energy in alcohol and in water (i.e. DETA-CO 2 has 12.5 kcal/mol ΔGsol in 1-propanol less than that in water). The optimization of the DETA/1-propanol/H 2 O solution was confirmed to be 30% DETA + 30% 1-propanol + 40% H 2 O (D30P30H40). It was found that above 90% of CO 2 loading was enriched in lower phase. 13C NMR spectrum indicated that carbamate and bicarbonate was formed in lower phase and 1-propanol acted as a good physical solvent to trigger phase separation and facilitate the reaction between amine and CO 2. [ABSTRACT FROM AUTHOR]