Understanding water behavior through activity coefficients in aqueous solutions: insights from experimental and modeled relative static permittivity

The relative static permittivity is a pivotal property in electrolyte solutions, playing a crucial role in thermodynamic calculations. This study employs the “Ion − Ion + Ion-Water” approach to calculate individual ionic activity coefficients within various electrolyte solutions at 298.15 K, including aqueous sodium chloride solutions at different temperatures. Two types of relative static permittivity are employed for these calculations: experimental values and modeled values. Notably, the “Ion − Ion + Ion − IWater” approach demonstrates robust performance in determining activity coefficients, regardless of the type of relative static permittivity used. Although minor discrepancies arise between calculations employing these two approaches, this research also delves into the impacts of varying relative static permittivity on activity coefficient determination.