Investigation of CO2Absorption Kinetics and Desorption Performance in Aqueous 1-(2-Aminoethyl)-3-methylimidazolium Bromine Solution

The absorption rate and absorption amount of CO 2 were determined at different 1-(2-aminoethyl)-3-methylimidazolium bromine ([Aemim][Br]) concentrations, absorption temperatures, and CO 2 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 CO 2 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 CO 2 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 CO 2 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 × 10 10 exp(−5440/ T ). By contrast to common CO 2 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.