A hybrid predictive model has been developed for accurate prediction of thermodynamics of carbon dioxide separation by aqueous alkanolamines. The model incorporates equation of state/excess Gibbs energy model into Kent�Eisenberg approach to predict carbon dioxide�alkanolamine�water equilibria. The approach imparts theoretical corrections to Kent�Eisenberg approach and significantly extends their range of application for monoethanolamine, diethanolamine, methyldiethanolamine, and 2-amino-2-methyl-1-propanol solutions. The proposed model suitably predicts thermodynamics of carbon dioxide separation, well beyond the regressed range of parameters. The results are in excellent agreement with experimental data for a wide range of process parameters and found superior to existing thermodynamic approaches. © 2016 Taylor & Francis.