In this study, a new equilibrium solubility data for carbon dioxide in aqueous solutions of 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ) were provided. The two famous Deshmukh-Mather and Kent Eisenberg thermodynamic models were utilized to predict the CO2 absorption. CO2 loading data in aqueous AMP + PZ were assessed over the different ranges of temperatures (293, 303, 313 and 323 K), CO2 partial pressures (18.13, 27.19 and 72.52 kPa) and solvent concentrations ((0.1, 0.2, 0.3 M PZ) + (1.5, 2, 3, 4 M AMP)) in local atmospheric pressure (90.66 kPa) on samples of flue gases from thermal and central power plants of Esfahan Steel Company. For high partial pressure of CO2 in feed gas stream, the addition of PZ promotes the absorption rate. However, at low CO2 partial pressure, PZ addition results in less CO2 loading. The Deshmukh-Mather model could provide an accurate prediction of the experimental data at high partial pressure of CO2 whereas the modified Kent-Eisenberg model could capture the inverse effects of the PZ at low partial pressure and provides a relatively good approximation of experimental data at low partial pressure. The Average Absolute Deviation percentage (AAD%) used to adjust the parameters of the models. The AAD was calculated 15.02% and 19.49% for the Deshmukh-Mather and Kent-Eisenberg models, respectively. (C) 2018 Elsevier Ltd. All rights reserved.