Kinetics of CO2 absorption into aqueous 1-ethyl-3-methylimidazolium glycinate solution

• The effect factors of CO2 absorption and physicochemical parameters were discussed.
• Aqueous [C2mim][Gly] solution was characterized for CO2 absorption purpose.
• The CO2 absorption into aqueous [C2mim][Gly] solution was the fast pseudo-first order reaction.
• The reaction rate constant (k2) and activity energy were calculated out.
• As carbon chain linked with imidazole ring increased, solubility of CO2 and activity energy increased.

The kinetic of CO2 absorption into aqueous 1-ethyl-3-methylimidazolium glycinate ([C2mim][Gly]) solution was investigated using a double stirred-cell absorber. Density and viscosity of the [C2mim][Gly]) solution were determined, then diffusion coefficient (DCO2)DCO2 and solubility of CO2 were estimated. The effects of [C2mim][Gly] concentration, absorption temperature and CO2 concentration in bulk gas were studied. Calculated results proved that CO2 absorption into aqueous [C2mim][Gly] solution was carried out according to a fast pseudo-first order reaction regime. Hatta number (Ha), the enhancement factor (E  ), the overall reaction rate constant (kOVkOV) and the second-order rate constant (k2) were calculated by gas–liquid two-film theory. The result showed that E   was linear with CILs1/2, and the second-order rate constant was expressed as following equation: k2=6.041×106exp-2801T.