MODEL FOR DESCRIBING ACTIVITY-COEFFICIENTS IN MIXED ELECTROLYTE AQUEOUS-SOLUTIONS

Most models for describing activity coefficients in ionic solutions are only appropriate for single aqueous electrolyte solutions. Extensions to mixed electrolyte solutions are rarely found and are often unreliable, especially at higher electrolyte concentrations. A new model is developed by combining ionic solvation equilibria and physical interaction forces. It is shown that by using the parameters correlated from single electrolyte aqueous systems, the activity coefficients in mixed electrolyte aqueous solutions can be accurately predicted up to the solubility limit, for example, at very high ionic strength.