Extrapolation of surface tensions of electrolyte and associating mixtures solutions

•A new surface tension model using Gibbs method and Ion-based SAFT2 is proposed.•Activity coefficients are represented accurately by Ion-based SAFT2.•Surface tensions of single/mixed electrolyte solutions are well extrapolated.•Surface tensions of associating mixtures are well extrapolated.

A new surface tension model is proposed, based on the Gibbs phenomenological surface-phase method, coupled with Ion-based Statistical Associating Fluid Theory (Ion-based SAFT2). The model was used to extrapolate the surface tensions of aqueous electrolyte solutions and mixed electrolyte solutions, as well as systems of associating mixtures at different temperatures and concentrations, and was found to give good agreement with experimental data from the literature.