Regenerable potassium-based alumina sorbents prepared by CO2 thermal treatment for post-combustion carbon dioxide capture

Potassium carbonate supported on alumina is used as a solid sorbent for CO 2 capture at low temperatures. However, its CO 2 capture capacity decreases immediately after the first cycle. This regeneration problem is due to the formation of the by-product [KAl(CO 3 )(OH) 2 ] during CO 2 sorption. To overcome this problem, a new regenerable potassium-based sorbent was fabricated by CO 2 thermal treatment of sorbents prepared by the impregnation of δ -alumina with K 2 CO 3 in the presence of 10 vol% CO 2 and 10 vol% H 2 O. The CO 2 capture capacities of the new regenerable sorbents were maintained over multiple CO 2 sorption tests. These results can be explained by the fact that the sorbent prepared by CO 2 thermal treatment did not form any by-product during CO 2 sorption. Based on these results, we suggest that the regeneration properties of potassium-based sorbents using δ -alumina could be significantly improved by the use of the CO 2 thermal treatment developed in this study.