n -Butanol-Regulated Phase Separation of Aminoethylethanolamine (AEEA) as an Efficient Absorbent for CO 2 Capture

Amine-based CO 2 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 CO 2 capture. The experimental results demonstrate that the obtained CPCA of AEEA/ n -BuOH/H 2 O exhibited a 44.0% higher cyclic capacity and 24.9% lower regeneration energy consumption compared to AEEA/H 2 O. 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 CO 2 products. Specifically, n -BuOH was present in the rich phase at only 3.2%, with the remainder consisting of CO 2 products. Moreover, the phase separation mechanism was elucidated by studying the difference in dipole moments of the substances during CO 2 capture. Overall, the n -BuOH-regulated AEEA-based CPCA shows promise as a candidate for practical CO 2 capture applications.