An Electrolyte Non-random-UNIQUAC Model for Thermodynamic Modeling of Binary and Multicomponent Aqueous Electrolyte Systems

摘要

An Electrolyte non-random-UNIQUAC (NR-UNIQUAC) local composition model is developed for calculation of the excess Gibbs energy and activity coefficients for binary and the multicomponent electrolyte solutions. A new expression for the energies of the reference cells in the random state is used and a modified version of the UNIQUAC model is provided. The high efficiency of the presented model is demonstrated through the correlation of the available experimental data for various electrolyte solutions. Obtained results are compared with those of Electrolyte-UNIQUAC-NRF model. The correlation of data was carried out using two different approaches, the single system correlation and the global optimization of the interaction parameters. In the single fitting approach, two adjustable binary interaction parameters of the model are regressed using the experimental mean activity coefficient data of binary solutions. In the global approach, the anion-water and cation-anion interaction energy parameters of different ions are calculated via simultaneous correlation of the mean activity coefficient data of the forty-nine binary electrolyte solutions. In both approaches, the adjustable parameters are calculated in a wide range of electrolyte concentrations and at different temperatures, so that these parameters can be used to predict the osmotic coefficient data of many binary systems. Moreover, the solubility and osmotic coefficient data of ternary electrolyte solutions were predicted using the previously obtained binary parameters. Using the present model, the predicted data for the binary and multicomponent electrolyte solutions are in good agreement with the experimental data. When compared to Electrolyte-UNIQUAC-NRF model, the present model is more accurate. Additionally, the presence of salt-salt interaction parameters in the electrolyte-NR-UNIQUAC model can further improve its efficiency when experimental data for a ternary system is available.