Journal of Solution Chemistry

, Volume 38, Issue 2, pp 171–186 | Cite as

A New Gibbs Energy Model for Obtaining Thermophysical Properties of Aqueous Electrolyte Solutions

  • K. Khederlou
  • G. R. Pazuki
  • V. Taghikhani
  • M. Vossoughi
  • C. Ghotbi


In this paper, a new Gibbs energy model is proposed to study the thermophysical properties of aqueous electrolyte solutions at various temperatures. The proposed model assumes that the electrolytes completely dissociate in solution. The model also has two temperature-independent adjustable parameters that were regressed using experimental values of the mean ionic activity coefficients (MIAC) for 87 electrolyte solutions at 298.15 K. Results from the proposed model for the MIAC were compared with those obtained from the E-Wilson, E-NRTL, Pitzer and the E-UNIQUAC models, and the adjustable model parameters were used directly to predict the osmotic coefficients at this temperature. The results showed that the proposed model can accurately correlate the MIAC and predict the osmotic coefficients of the aqueous electrolyte solutions better on the average than the other models studied in this work at 298.15 K. Also, the proposed model was examined to study the osmotic coefficient and vapor pressure for a number of aqueous electrolyte solutions at high temperatures. It should be stated that in order to calculate the osmotic coefficients for the electrolyte solutions, the regressed values of parameters obtained for the vapor pressure at high temperatures were used directly. The results obtained for the osmotic coefficients and vapor pressures of electrolyte solutions indicate that good agreement is attained between the experimental data and the results of the proposed model. In order to unequivocally compare the results, the same experimental data and same minimization procedure were used for all of the studied models.


Electrolyte solution Local composition Gibbs energy Thermophysical properties 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Debye, P., Hückel, E.H.: The theory of electrolytes. I. Lowering of freezing point and related phenomena. Phys. Zeit. 24, 185–206 (1923) Google Scholar
  2. 2.
    Pitzer, K.S.: Thermodynamics of electrolytes. I. Theoretical basis and general equations. J. Phys. Chem. 77, 268–277 (1973) CrossRefGoogle Scholar
  3. 3.
    Pitzer, K.S., Mayorga, G.: Thermodynamics of electrolytes. II. Activity and osmotic coefficients for strong electrolytes with one or both ions univalent. J. Phys. Chem. 77, 2300–2308 (1973) CrossRefGoogle Scholar
  4. 4.
    Chen, C.C.: A segment-based local composition model for the Gibbs energy of polymer solutions. Fluid Phase Equil. 83, 301–312 (1993) CrossRefGoogle Scholar
  5. 5.
    Chen, C.C., Evans, L.B.: A local composition model for the excess Gibbs energy of aqueous electrolyte systems. AIChE J. 32, 444–454 (1986) CrossRefGoogle Scholar
  6. 6.
    Cruz, J.L., Renon, H.: New thermodynamic representation of binary electrolyte solutions nonideality in the whole range of concentrations. AIChE J. 24, 817–830 (1978) CrossRefGoogle Scholar
  7. 7.
    Zhao, E., Yu, R.M., Sauvé, E., Khoshkbarchi, M.K.: Extension of the Wilson model to electrolyte solutions. Fluid Phase Equil. 173, 161–175 (2000) CrossRefGoogle Scholar
  8. 8.
    Xu, X., Macedo, E.A.: New modified Wilson model for electrolyte solutions. Ind. Eng. Chem. Res. 42, 5702–5707 (2003) CrossRefGoogle Scholar
  9. 9.
    Thaghikhani, V., Vera, J.H.: Correlation of activity coefficients in electrolyte solutions using a Kelvin hard sphere-mean spherical approximation (K-MSA) model. Ind. Eng. Chem. Res. 39, 759–766 (2000) CrossRefGoogle Scholar
  10. 10.
    Ghotbi, C., Azimi, G., Thaghikhani, V., Vera, J.H.: On the correlation of the activity coefficients in aqueous electrolyte solutions using the K-MSA model. Ind. Eng. Chem. Res. 42, 1279–1284 (2003) CrossRefGoogle Scholar
  11. 11.
    Messnaoui, B., Ouiazzane, S., Bouhaouss, A., Bounahmidi, T.: A modified electrolyte-Uniquac model for computing the activity coefficient and phase diagrams of electrolytes systems. Calphad 32, 566–576 (2008) CrossRefGoogle Scholar
  12. 12.
    Pazuki, G.R., Taghikhani, V., Vossoughi, M.: Correlation and prediction the activity coefficients and solubility of amino acids and simple peptide in aqueous solution using the modified local composition model. Fluid Phase Equil. 255, 160–166 (2007) CrossRefGoogle Scholar
  13. 13.
    Pazuki, G.R., Taghikhani, V., Vossoughi, M.: Study of VLE phase behavior and correlating the thermophysical properties of polymer solutions using a local composition based model. J. Appl. Polymer Sci. (2009, in press) Google Scholar
  14. 14.
    Robinson, R.A., Stokes, R.H.: Electrolyte Solutions, 2nd edn. Butterworth, London (1970) Google Scholar
  15. 15.
    Zaytsev, I.D., Aseyev, G.G.: Properties of Aqueous Solutions of Electrolytes, 1st edn. CRC Press, Boca Raton (1992) Google Scholar
  16. 16.
    Prausnitz, J.M., Lichtenthaler, R.N., de Azevedo, E.G.: Molecular Thermodynamics of Fluid Phase Equilibria, 3rd edn. Prentice Hall, Englewood Cliffs (1999) Google Scholar
  17. 17.
    Vargaftik, N.B., Vinogradov, Y.K., Yargin, V.S.: Handbook of Physical Properties of Liquids and Gases (Pure Substances and Mixtures), 3rd augmented and revised edn. Begell House, New York (1996) Google Scholar
  18. 18.
    Patil, K.R., Tripathi, A.D., Pathak, G., Katti, S.S.: Thermodynamic properties of aqueous electrolyte solutions. 2. Vapor pressure of aqueous solutions. J. Chem. Eng. Data 36, 225–230 (1991) CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • K. Khederlou
    • 1
  • G. R. Pazuki
    • 1
  • V. Taghikhani
    • 1
  • M. Vossoughi
    • 1
    • 2
  • C. Ghotbi
    • 1
  1. 1.Department of Chemical and Petroleum EngineeringSharif University of TechnologyTehranIran
  2. 2.Institute for Nano-science and Nano-technologySharif University of TechnologyTehranIran

Personalised recommendations