Incorporation of Amino Acid-Functionalized Ionic Liquids into Highly Porous MOF-177 to Improve the Post-Combustion CO2 Capture Capacity

Abstract

This study presents the encapsulation of two amino acid-based ionic liquids (AAILs), 1-ethyl-3-methylimidazolium glycine [Emim][Gly] and 1-ethyl-3-methylimidazolium alanine [Emim][Ala], in a highly porous metal-organic framework (MOF-177) to generate state-of-the-art composites for post-combustion CO₂ capture. Thermogravimetric analysis (TGA) demonstrated a successful encapsulation of the AAILs, with a dramatic reduction in the composites' surface areas and pore volumes. Both [Emim][Gly]@MOF-177 and [Emim][Ala]@MOF-177 had close to three times the CO₂ uptake of MOF-177 at 20 wt.% loading, 0.2 bar, and 303 K. Additionally, 20-[Emim][Gly]@MOF-177 and 20-[Emim] [Ala]@MOF-177 enhanced their CO₂/N₂ selectivity from 5 (pristine MOF-177) to 13 and 11, respectively.

Keywords: CO2 capture; MOF-177; amino acid ionic liquid (AAIL); ionic liquid; metal organic framework (MOF); task-specific ionic liquid (TSIL).