Phase equilibria for aqueous systems containing salts and carbon dioxide: application of Pitzer's theory for electrolyte solutions

The semiempirical specific-interaction model developed by Pitzer is applied to aqueous salt solutions that also contain a dissolved nonelectrolyte. Pitzer's model is used to describe phase equilibria for aqueous solutions containing either sodium chloride and carbon dioxide to 600 bar or sodium sulfate and carbon dioxide to 200 bar at several temperatures. In contrast to predictions reported by previous authors, we find that, over wide ranges of pressure and temperature, Pitzer's equations provide an excellent description of salt solubilities in these ternary systems.