Low-energy regeneration of CO2-rich amine solution by acid-functionalized ionic liquids catalyst

Abstract

Excessive energy demands, coupled with the low regeneration efficiency of absorbents, present critical barriers to the wider industrial scalability of amine-based carbon dioxide (CO2) capture technologies. The development of effective desorption catalysts offers a promising solution to these limitations, with recent research predominantly focusing on solid acid catalysts. Here, we introduce an acid-functionalized ionic liquid (AFIL) catalyst, [Et3NH][AlCl4], which demonstrates exceptional performance in accelerating CO2 desorption from saturated monoethanolamine (MEA) solutions. Utilizing AFILs enhanced CO2 desorption efficiency by 64–83 %, while reducing energy consumption by 29–40 %, with stable desorption performance over five cycles without compromising subsequent absorption. Experimental analyses and theoretical calculations revealed that AFILs functioned as proton transfer carriers, efficiently facilitating the transfer of protons from MEAH+ to MEACOO−. Thus, the MEA desorption performance at 100 °C is greatly enhanced. This study presents a homogeneous catalytic system based on AFILs, providing critical insights into the development of next-generation homogeneous catalysts for CO2 capture technologies.