<i>n</i>-Butanol-Regulated Phase Separation of Aminoethylethanolamine (AEEA) as an Efficient Absorbent for CO₂ Capture

Amine-based CO2 phase change absorbents (CPCAs) have received considerable attention for their potential energy efficiency. This study presents an aminoethylethanolamine (AEEA)-based CPCA using n-butanol (n-BuOH) as a phase separator for efficient CO2 capture. The experimental results demonstrate that the obtained CPCA of AEEA/n-BuOH/H2O exhibited a 44.0% higher cyclic capacity and 24.9% lower regeneration energy consumption compared to AEEA/H2O. In addition, quantitative NMR analysis of the species distribution in both the upper and lower phases revealed an effective separation between the phase separator and the CO2 products. Specifically, n-BuOH was present in the rich phase at only 3.2%, with the remainder consisting of CO2 products. Moreover, the phase separation mechanism was elucidated by studying the difference in dipole moments of the substances during CO2 capture. Overall, the n-BuOH-regulated AEEA-based CPCA shows promise as a candidate for practical CO2 capture applications.