Systematic evaluation of parameterization approaches for the ePPC-SAFT model for aqueous alkali halide solutions. II. Alkali bromides, iodides, fluorides, and lithium halides

Abstract

In this work, state-of-the-art ion-specific parameter sets for the ePPC-SAFT model are obtained for 15 aqueous alkali halide solutions based on extensively collected and critically evaluated databases. The association approach, which has been proven the best for accounting for the short-range interactions, is here extended to all the alkali halides. Efforts are made to improve modeling accuracy. The impact of anion association site number on modeling accuracy is investigated. Recommended parameter sets are presented. Only 7 adjustable parameters altogether are needed for the 4 salts with the same anion, e.g., NaBr, KBr, RbBr, and CsBr. It is found that Li+-water dispersion needs to be accounted for to reach the same accuracy for Li+ salts as for the other salts. Thus, 7 parameters altogether are needed for LiCl, LiBr, and LiI. The obtained model and parameter sets are very accurate for correlating the properties included in the regression, mean-ionic activity coefficient, vapor-liquid equilibria, and density, and for predicting the osmotic coefficient. In all cases, maximum deviations are within a few percent. The contributions of the model terms are analyzed.