Comparative analysis of the carbon dioxide absorption and recuperation capacities in aqueous 2-(2-aminoethylamino)ethanol (AEE) and blends of aqueous AEE and N-methyldiethanolamine solutions

A study of carbon dioxide (CO2) absorption/desorption has been carried out in diverse aqueous amine solutions consisting of 2-(2-aminoethylamino)ethanol (AEE), monoethanolamine (MEA), and the blends of AEE and N-methyldiethanolamine (MDEA) at different concentrations to compare the CO2 loading and recuperation properties of these amines. The CO2 absorption loading has been estimated in 0.476, 0.951, 1.427, and 2.378 M AEE solutions, a 2.378 M MEA solution, and two blends of 1.427 M AEE + 0.418 M MDEA and 1.427 M AEE + 0.836 M MDEA with two CO2 concentrations of 5.01 and 100 vol % at 23 degrees C and a flow rate of 3.067 L/min. The CO2 desorption was performed by heating these solutions at 100-102 degrees C. The results revealed that the AEE diamine possesses a greater CO2 absorption capacity than MEA while its CO2 desorption capacity was inferior to that observed for MEA. Moreover, the CO2 recuperation capacity obtained for AEE was greater than that of MEA at the same concentration. Interestingly, the CO2 absorption in an aqueous AEE solution was also slightly increased in the presence of MDEA while its desorption was highly enhanced, resulting in an increase of about 1.5% of its CO2 recuperation capacity. Taken together, these results suggest that the structural properties of AEE, including the presence of two amino groups, as compared to MEA could favor its CO2 absorption and recuperation capacities. Therefore, AEE and the blends of AEE + MDEA could represent interesting absorbents for the development of new methods to eliminate the CO2 emanation into the atmosphere by industrial combustion processing.