Measurement and Correlation of the Activity Coefficients of H⁺ And HSO₃^- in Concentrated Aqueous Solutions of NaCl

Abstract

The activity coefficients of HSO₃^– and H⁺ were determined in concentrated aqueous solutions of NaCl in order to provide a theoretical basis for using sea water as a solvent in flue gas desulfurization processes.
The activity coefficient of HSO₃^– was determined at 313 K and 323 K by measuring the pH of mixtures of NaCl, H₂O and small amounts of NaHSO₃ at a known partial pressure of SO₂. The activity coefficient of H⁺ was determined over a temperature range of 296 K–333 K by measuring the pH of mixtures of NaCl, H₂O and small amounts of HCl.
As the ionic strength increased, the activity coefficient of HSO₃^– decreased while that of H⁺ increased. The Pitzer Equation could correlate the activity coefficients of both species with reasonable accuracies for practical use.