Critical evaluation of CuSO4-H2O system up to solubility limit, from eutectic point to 373.15 K

Abstract

• CuSO 4 -H 2 O system is modelled from freezing point to boiling point. • The behaviour of the electrolyte solution is described by Pitzer model. • Several parameter sets with different temperature dependency were evaluated. • Only four parameters with eight temperature dependent terms are required. • Model is tested against independent vapour pressure and electrochemical cell data. The solubility of copper(II) sulfate in water as a function of temperature and ionic strength is successfully modelled using Pitzer formalism. Four types of experimental data from the literature were implemented for the assessment, namely activity and osmotic coefficients, freezing point depression and solubility of CuSO 4 in water. This work proved that four Pitzer parameters with eight terms are sufficient to create a consistent thermodynamic model of the CuSO 4 -H 2 O system up to 5 mol/kg-H 2 O of CuSO 4 , from the eutectic point to 373.15 K. The whole optimization study included a critical deviation analysis to sort out less reliable experimental data. To verify the results of this work, comparisons were carried out with experimental data which were not included in the assessment, i.e. the vapour pressure of the saturated solution, thermodynamic values of the cell reaction as well as electrochemical cell potential (EMF).