Importance of the Relative Static Permittivity in electrolyte SAFT-VR Mie Equations of State

The influence and importance of the relative static permittivity (RSP) in electrolyte equations state is examined for case aqueous sodium chloride. Using SAFT-VR Mie model, Debye-Hückel (DH) or Mean-Spherical Approximation (MSA) terms, as well Born-solvation term, are used to formulate an equation state. RSP obtained from a variety models, each differing their dependencies; we consider constant, temperature-, density- composition-dependent models. For fair comparison between different combinations electrostatic all ion-related parameters priori. A novel combining rule proposed obtain unlike solvents ions; its reliability systems. We also compare performance parameterised Both DH MSA terms yield similar results almost properties conditions. models have more-significant impact. Liquid densities solvent saturation pressures showed limited changes whereas osmotic coefficients, mean ionic activity coefficients carbon dioxide solubilities observed drastically behaviour. Analysing contributions various activities species mixture reveals important balance where significant over this balance, particularly when these carry solvent- ion-composition dependence.