n-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.