The role of ion-water interactions in the solubility of ionic solutions

Molecular dynamics simulations are performed to analyze the solubility of NaCl and NaI salts from dilute to saturated aqueous solutions. The TIP4Q water model, which reproduces the experimental dielectric constant, is used with ions where the interaction parameters were obtained to reproduce some experimental properties of the crystal and in solution. It is shown the models fail to describe the correct behavior of ions at high concentrations when the Lorentz-Berthelot mixing rules for the cross interactions are used. The hydration of ions at low concentrations and the precipitation of ions at saturated solutions are observed after adding a screening short range function on electrostatic interactions on pairs where the short range repulsion was not taken into account. (C) 2012 Elsevier B.V. All rights reserved.