• Economou, Ioannis G.
• Kontogeorgis, Georgios M.
• Novak, Nefeli Effrosyni
• Castier, Marcelo

Abstract

In this work, the eSAFT-VR Mie equation of state (EoS) is extended tolow relative permittivity, non-aqueous solutions. The effect of usingdifferent relative permittivity relations for the electrolyte solutionsis studied, ranging from experimentally measured values to asalt-composition independent relative permittivity. Furthermore, theeffect of using different approaches for the characteristic diameters inthe Debye-Hückel and Born terms is presented. The eSAFT-VR Mie EoS isreparametrized using aqueous mean ionic activity coefficients,individual ion activity coefficients and densities with differentrelations for the relative permittivity. Afterwards, the performance ofthese models on non-aqueous solutions is evaluated based on the MeanIonic Activity Coefficients of salts in non-aqueous solutions. Theconclusion is that a mole fraction based mixing rule for the relativepermittivity yields the best extrapolation from aqueous to non-aqueoussolutions, and achieves quantitative predictions for the mean ionicactivity coefficients of monovalent salts in methanol and ethanolwithout additional adjustable parameters.

Topics

• impedance spectroscopy
• dielectric constant