Chemical solvent in chemical solvent: A class of hybrid materials for effective capture of CO₂

Abstract

Amino acid ionic liquids (AAILs) are chemical solvents with high reactivity to CO 2 . However, they suffer from drastic increase in viscosity on the reaction with CO 2 , which significantly limits their application in the industrial capture of CO 2 . In this work, 1‐ethyl‐3‐methylimidazolium acetate ([emim][Ac]) which also exhibits chemical affinity to CO 2 but low viscosity, and its viscosity does not increase drastically after CO 2 absorption, was proposed as the diluent for AAILs to fabricate hybrid materials. The AAIL+[emim][Ac] hybrids were found to display enhanced kinetics for CO 2 absorption, and their viscosity increase after CO 2 absorption are much less significant than pure AAILs. More importantly, owing to the fact that [emim][Ac] itself can absorb large amount of CO 2 , the AAIL+[emim][Ac] hybrids still have high absolute capacities of CO 2 . Such hybrid materials consisting of a chemical solvent plus another chemical solvent are believed to be a class of effective absorbents for CO 2 capture. © 2017 American Institute of Chemical Engineers AIChE J , 64: 632–639, 2018