In this work, a coupled mass transfer-reaction kinetics-equilibrium model has been developed for absorption of CO2 into aqueous piperazine (PZ), PZ activated aqueous N methyldiethanolamine (MDEA) and PZ activated aqueous 2-amino-2-methyl-1-propanol (AMP) solvents incorporating the important reversible reactions in the liquid phase. The bulk equilibrium concentrations as well as the interfacial concentration profiles of all chemical species can be predicted at any point in a gas-liquid contactor using the model. The set of partial differential equations along with nonlinear algebraic equations are solved numerically. The model is validated with experimental results of steady state absorption measurements of CO2 into aqueous PZ, aqueous (MDEA + PZ), and aqueous (AMP + PZ) in a wetted wall contactor. The rates of absorption of CO2 into these solvents have been measured at various temperatures, CO2 partial pressures, and various relative compositions of MDEA/PZ and AMP/PZ in the blends. New kinetic parameters for the reactions of CO2 with aqueous PZ, aqueous (MDEA + PZ) and aqueous (AMP + PZ) have been obtained using the developed mathematical model and the measured rates of absorption. The model has also been used for parametric sensitivity analyses to determine the effects of various important parameters, such as CO2 interfacial concentration, Henry’s law constants for CO2, diffusion coefficients of CO2 and all liquid phase chemical species, and the reaction rate coefficients on the rates of absorption of CO2 and the enhancement factors. Steady state absorption measurements of this work have shown that the CO2 absorption rates into aqueous MDEA and aqueous AMP increase significantly with the addition of small amounts of PZ in these alkanolamines, while more pronounced effect has been observed for aqueous (AMP + PZ) solvent at high CO2 partial pressures.