In this study, new equilibrium solubility data for carbon dioxide in aqueous solutions of 2-amino-2-methyl-1-propanol and piperazine (PZ) are provided. The two famous Deshmukh-Mather and Kent Eisenberg thermodynamic models are utilized to predict the CO2 absorption. The experimental data show that the solubility of CO2 decreases as the temperature increases. Our data suggest that the addition of PZ has different effects on CO2 absorption under different partial pressure of the CO2 in the gas stream. For high partial pressure, the addition of PZ promotes the absorption performance. However, at low CO2 partial pressure, PZ addition results in less saturated CO2 loading. The Deshmukh-Mather model can provide an accurate prediction of the experimental data at high partial pressure of CO2 (i.e. AAD = 3.4%) whereas the modified Kent-Eisenberg model can capture the inverse effects of the PZ at low partial pressure and provides a relatively good approximation of experimental data at low partial pressure (i.e. AAD = 10%).