Potassium carbonate based solvents have the potential for capturing CO2 from emission sources such as power stations burning fossil fuels. However, due to poor reaction kinetics a rate promoter is considered necessary to improve the rate of reaction of CO2 with the solvent. Using a characterized wetted-wall column, we have studied the reaction kinetics of CO2 into unpromoted and borate-promoted 30 wt% potassium carbonate solutions. Results presented here show that, at 80 degrees C. addition of small amounts of boric acid (0.2 M, 0.6 M and 1.5 M) accelerate the overall absorption process of CO2 in carbonate solvents by 3%, 10% and 29% respectively. The Arrhenius expression for the reactions CO2 + OH- and CO2 + B(OH)(4)(-) are k(OH) [M-1 s(-1)] = 2.53 x 10(11) exp(-4311/T [K]) and k(borate) [M-1 s(-1)] = 5.5 x 10(11) exp(-6927/T [K]); and the activation energies are 35.8 kJ mol(-1) and 57.6 kJ mol(-1) respectively. Experiments were conducted between 40 degrees C and 80 degrees C and at a bulk partial pressure of CO2 of 90 kPa. (C) 2012 Elsevier B.V. All rights reserved.