An aqueous solution of 2 M 1,4-butanediamine (BDA) blended with 4 M 2-(diethylamino)-ethanol (DEEA) has been proven to be a promising solvent in previous work, and BDA is a potential amine to accelerate the reaction rate of DEEA with CO2. In the present work, kinetics of CO2 absorption into aqueous solutions of BDA, DEEA, and their mixtures were studied using a wetted wall column (WWC) at 25, 40, and 60 degrees C with the driving force of 3-35 kPa. The BDA concentrations were 1, 2, and 3 M, with DEEA concentrations of 2, 3, 4, and 5 M, while those of the BDA/DEEA mixtures were 1 M BDA/4 M DEFA, 2 M BDA/3 M DEFA, 2 M BDA/4 M DEEA and 2.54 M BDA/2.73 M DEEA. The results show that the reaction rate constant of BDA is larger than most of the amines but lower than piperazine. BDA can largely accelerate the reaction of solvents with CO2, and the overall reaction of their mixtures can be regarded as a reaction between CO2 and DEEA in parallel with the reaction of CO2 with BDA.