SEPARATIONS Development of Supported Ethanolamines and Modified Ethanolamines for CO2 Capture

Liquid amines can be immobilized within the pores of polymeric supports to provide a regenerable CO2 sorbent. This paper describes the capture of CO2 by a range of ethanolamines (primary, secondary, and tertiary) immobilized within the pores of high-surface-area poly(methyl methacrylate) beads. These supported amines were used to remove low concentrations (7.6 mmHg) of CO2 by a pressure swing absorption process, where low-pressure vacuum was used to desorb the CO2 and regenerate the sorbent. The effect on CO2 capture of modification of primary amines to secondary amines by reaction with acrylonitrile was also evaluated. The modified amines provided nearly a factor of 2 increase in CO2 removal capacity compared to the original primary amines. These results suggest that modified amines could potentially be used for CO2 capture in space life support systems as well as for terrestrial flue gas CO2 removal applications.