• Kontogeorgis, Georgios M.
• Liang, Xiaodong
• Silva, Gabriel M.

Abstract

This work discusses the introduction of the concentration dependency ofrelative permittivity in the context of activity coefficient models atdifferent stages of the derivation of the models. We evaluate anexperimental correlation and the Michelsen–Mollerup–Breil model for therelative permittivity in order to assess the impact of using thesemodels both in the Debye–Hückel and Born equations. Our results showthat the effects of introducing the relative permittivity at differentlevels in the models derivation are significant and quantitative. Usingthe concentration dependency as early as before deriving the Helmholtzfree energy has the best overall performance. We derive a general methodto include any relative permittivity correlation forconcentration-dependency before the charging process to calculate theHelmholtz free energy, with no clear advantage on using charge-dependentor independent models.

Topics

• dielectric constant