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 CO2. However, they suffer from drastic increase in viscosity on the reaction with CO2, which significantly limits their application in the industrial capture of CO2. In this work, 1‐ethyl‐3‐methylimidazolium acetate ([emim][Ac]) which also exhibits chemical affinity to CO2 but low viscosity, and its viscosity does not increase drastically after CO2 absorption, was proposed as the diluent for AAILs to fabricate hybrid materials. The AAIL+[emim][Ac] hybrids were found to display enhanced kinetics for CO2 absorption, and their viscosity increase after CO2 absorption are much less significant than pure AAILs. More importantly, owing to the fact that [emim][Ac] itself can absorb large amount of CO2, the AAIL+[emim][Ac] hybrids still have high absolute capacities of CO2. Such hybrid materials consisting of a chemical solvent plus another chemical solvent are believed to be a class of effective absorbents for CO2 capture. © 2017 American Institute of Chemical Engineers AIChE J, 64: 632–639, 2018