Solubility of carbon dioxide in aqueous 2.5 M of diethylenetriamine (DETA) solution

Thermodynamic modeling of the solubility of carbon dioxide (CO2) vapor/liquid equilibrium into aqueous solutions of 2.5 M diethylenetriamine (DETA) was developed. The Deshmukh-Mater (DM) model was implemented to this system for predicting the CO2 partial pressures against loading for different temperatures. A two step procedure, in general, is needed to fit the parameters in the DM model. However, in this work only the first step (the Debye–Hückel part) was executed because, with the complexity of the DETA system, the available experimental data material was not large and varied enough to merit going into this procedure. The model fits the CO2 partial pressure data reasonably well up to loading of about 1.0 while the predicted isothermal heat of absorption based on the equilibrium agree reasonably well for loadings in the range 0.6 to 1.2. The fitting clearly indicated that the regression parameters need to be further improved and that binary interaction parameters should be taken into account.