Investigation of CO2 Absorption Kinetics and Desorption Performance in Aqueous 1-(2-Aminoethyl)-3-methylimidazolium Bromine Solution

The absorption rate and absorption amount of CO2 were determined at different 1-(2-aminoethyl)-3-methylimidazolium bromine ([Aemim][Br]) concentrations, absorption temperatures, and CO2 content in order to optimize operational conditions in our study. Meanwhile, the effects of regeneration temperature, regeneration time, and regeneration circles on the regeneration efficiency of CO2 saturated [Aemim] [Br] solution were discussed, respectively. On the basis of these experiments, the kinetic data (i.e., in terms of the pseudo-first-order rate constant (k(ov)), the second-order reaction rate constant (k(2)) and heat of CO2 absorption was calculated at 303 K as [Aemim][Br] concentration varied from 0.1 to 2.0 mol.L-1. The result showed that the process of CO2 absorption was a fast pseudo-first-order reaction regime. According to the kinetic data at 293-323 K, the activation energy of reaction was calculated by the Arrhenius equation, and the second-order reaction rate constant can be expressed as follows: k(2) = 1.997 X 10(10) exp(-5440/T). By contrast to common CO2 absorbents (i.e., MEA, DEA) and amino acid ionic liquids (i.e., 1-ethyl-3-methylimidazole glycinate, 1-butyl-3-methylimidazole glycinate), [Aemim] [Br] has the best regeneration efficiency but lower absorption rate under the same conditions.