Carbone capture by absorption-regeneration technology is a well-known process. However, the development and utilization of new solvents remains crucial to lower its energy consumption. Therefore, an accurate thermodynamic modeling is essential for the process simulation and optimization. This work focuses on the thermodynamic modeling of CO2 absorption in aqueous solutions of N,N-diethylethanolamine (DEEA), N-methyl-1,3-propanediamine (MAPA) and their mixtures using electrolyte NRTL model. A novel thermodynamic modeling of DEEA-H2O-CO2, MAPA-H2O-CO(2 )and DEEA-MAPA-H2O-CO2 systems was developed. The modeling was carried out by considering the pure vapor pressures, excess enthalpies, dielectric constants, physical solubilities of CO2, partial and total pressures experimental data. The predicted and correlated data such as vapor-liquid equilibrium (VLE) and heat of CO2 absorption were compared favorably to experimental data from the literature. Liquid-liquid phase separation of a specific mixture of these two amines was also highlighted. Subsequently, the developed model could be used for further simulations at large scale considering that successful validation was performed at pilot scale. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.