An aqueous blend of monoethanolamine (MEA) and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) for CO2 absorption from simulated flue gas was investigated using a double stirred cell at a CO2 partial pressure of 15 kPa. It was found that the values of the enhancement factor (E) and the second-order reaction rate constant (k(2,mix)) for CO2 absorption into mixed solution were higher than those into a single MEA aqueous solution with the same MEA concentration. k(2,mix), and k(2,IL) were found to be 3487.6 m(3).kmol(-1).s(-1) and 1936.7 m(3)kmol(-1).s(-1) at 303.15 K, respectively. The Arrhenius equation of CO2 absorption was also estimated. The results proved the assumption that [Bmim]BF4 had an active effect on the CO2 hydration. The diffusion and solubility of the absorbent in the solution were the limiting factors of the reaction.