Integrated Screening of 40 Aqueous Amines for CO2 Capture: Linking Heat of Absorption, Absorption-Desorption Performance, and Relative Desorption Energy

Developing aqueous amine absorbents for post-combustion CO 2 capture requires considering capacity, kinetics, desorption, and energy performance simultaneously. In this study, 40 structurally diverse aqueous amines, including primary, secondary, tertiary, multiamine, sterically hindered, and cyclic amines, were evaluated using a novel absorption-desorption screening apparatus. The following properties were determined and compared through linear regression analysis. Rich and lean loadings, cyclic capacity, initial absorption and desorption rates, completion times, desorption ratio, relative desorption energy, and heat of absorption (ΔH abs ) were determined and compared through linear regression analysis. Rich loading exhibited a relatively stronger association with the initial absorption rate and absorption completion time. In contrast, the initial absorption rate showed a weaker relationship with completion time. ΔH abs exhibited negligible association with the initial absorption rate, but clearer relationships were observed with desorption completion time and relative desorption energy. The relative desorption energy was more strongly associated with the initial desorption rate and desorption completion time. This suggests that desorption dynamics provide complementary information beyond ΔH abs alone. Based on these profiles, DETA and AEPD were evaluated as binary blends. The DETA:AEPD=21:9 mass-ratio blend showed the best-performing composition among tested ratios. Its cyclic capacity and initial absorption and desorption rates that were 10.6%, 19.1%, and 34.7% higher than those of MEA, respectively, while reducing relative desorption energy by 32.5%. These results provide a multi-property framework for screening amines and guiding subsequent blend formulation.