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Clays and Clay Minerals

, Volume 59, Issue 3, pp 215–232 | Cite as

Solubility and Thermodynamic Properties of Carbonate-Bearing Hydrotalcite—Pyroaurite Solid Solutions with A 3:1 Mg/(Al+Fe) Mole Ratio

  • K. B. RozovEmail author
  • U. Berner
  • D. A. Kulik
  • L. W. Diamond
Article

Abstract

The naturally occurring layered double hydroxides (LDH, or anionic clays) are of particular interest in environmental geochemistry because of their ability to retain hazardous cations and especially anions. However, incorporation of these minerals into predictive models of water-rock interaction in contaminant environments, including radioactive-waste repositories, is hampered by a lack of thermodynamic and stability data. To fill part of this gap the present authors have derived properties of one of the complex multicomponent solid solutions within the LDH family: the hydrotalcite-pyroaurite series, Mg3(Al1−xFex)(OH)8(CO3)0.5·2.5H2O.

Members of the hydrotalcite-pyroaurite series with fixed MgII/(AlIII+FeIII) = 3 and various FeIII/(FeIII+AlIII) ratios were synthesized by co-precipitation and dissolved in long-term experiments at 23±2°C and pH = 11.40±0.03. The chemical compositions of co-existing solid and aqueous phases were determined by inductively coupled plasma-optical emission spectroscopy, thermogravimetric analysis, and liquid scintillation counting of 55Fe tracers; X-ray diffraction and Raman were used to characterize the solids. Based on good evidence for reversible equilibrium in the experiments, the thermodynamic properties of the solid solution were examined using total-scale Lippmann solubility products, ΣΠT. No significant difference was observed between values of SPT from co-precipitation and from dissolution experiments throughout the whole range of Fe/Al ratios. A simple ideal solid-solution model with similar end-member ΣΠT values (a regular model with 0 < WG < 2 kJ mol −1 sufficient to describe the full range of intermediate mineral compositions. In turn, this yielded the first estimate of the standard Gibbs free energy of the pyroaurite end member, G 298,Pyr o = −3882.60±2.00 kJ/mol, consistent with G 298,Htlc o = −4339.85 kJ/mol of the hydrotalcite end member, and with the whole range of solubilities of the mixed phases. The molar volumes of the solid-solution at standard conditions were derived from X-ray data. Finally, Helgeson’s method was used to extend the estimates of standard molar entropy and heat capacity of the end members over the pressure-temperature range 0−70°C and 1–100 bar.

Key Words

Aqueous Solubility Hydrotalcite LDH Molar Volume Pyroaurite Solid Solutions Thermodynamic Modeling 

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References

  1. Allada, R.K., Navrotsky, A., and Boerio-Goates, J. (2005) Thermochemistry of hydrotalcite-like phases in the MgOAl2O3-CoO2-H2O system: A determination of enthalpy, entropy and free energy. American Mineralogist, 90, 329–335.CrossRefGoogle Scholar
  2. Allmann, R. (1968) Crystal structure of pyroaurite. Acta Crystallographica. Section B. Structural Crystallography and Crystal Chemistry, B 24, 972.CrossRefGoogle Scholar
  3. Bish, D.L. and Howard, S.A. (1988) Quantitative phaseanalysis using the Rietveld method. Journal of Applied Crystallography, 21, 86–91.CrossRefGoogle Scholar
  4. Brindley, G.W. and Kikkawa, S. (1979) A crystal-chemical study of Mg, Al and Ni, Al hydroxy-perchlorates and hydroxy-carbonates. American Mineralogists, 64, 836–843.Google Scholar
  5. Brindley, G.W. and Kikkawa, S. (1980) Thermal-behavior of hydrotalcite and of anion-exchanged forms of hydrotalcite. Clays and Clay Minerals, 28, 87–91.CrossRefGoogle Scholar
  6. Carrado, K.A., Kostapapas, A., and Suib, S.L. (1988) Layered double hydroxides (LDHs). Solid State Ionics, 26, 77–86.CrossRefGoogle Scholar
  7. Cavani, F., Trifiro, F., and Vaccari, A. (1991) Hydrotalcitetype anionic clays: Preparation, properties and applications. Catalysis Today, 11, 173–301.CrossRefGoogle Scholar
  8. Chibwe, K. and Jones, W. (1989) Intercalation of organic and inorganic anions into layered double hydroxides. Journal of the Chemical Society - Chemical Communications, 926–927.Google Scholar
  9. Chisem, I.C. and Jones, W. (1994) Ion-exchange properties of lithium aluminum layered double hydroxides. Journal of Materials Chemistry, 4, 1737–1744.CrossRefGoogle Scholar
  10. Danton, A.R. (1991) Vegard’s law. Physical Review, 43, 3161–3164.CrossRefGoogle Scholar
  11. De Roy, A., Forano, C., El Malki, M., and Besse, J.-P. (1992) Anionic clays: Trends in Pillaring Chemistry. Van Nostrand Reinhold, New York.Google Scholar
  12. Drits, V.A. and Bookin, A.S. (2001) Crystal structure and X-ray identification of layered double hydroxides. Pp. 41–100 in: Layered Double Hydroxides. Present and Future (V. Rives, editor). Nova Science Publishers, New York.Google Scholar
  13. Drits, V.A., Sokolova, T.N., Sokolova, G.V., and Cherkashin, V.I. (1987) New members of the hydrotalcite-manasseite group. Clays and Clay Minerals, 35, 401–417.CrossRefGoogle Scholar
  14. Frost, R.L. and Reddy, B.J. (2006) Thermo-Raman spectroscopic study of the natural layered double hydroxide manasseite. Spectrochimica Acta. Part A. Molecular and Biomolecular Spectroscopy, 65, 553–559.CrossRefGoogle Scholar
  15. Gutmann, N. and Müller, B. (1996) Insertion of the dinuclear dihydroxo-bridged Cr(IV) aquo complex into the layered double hydroxides of hydrotalcite-type. Journal of Solid State Chemistry, 122, 214–220.CrossRefGoogle Scholar
  16. Helgeson, H.C., Delany, J.M., Nesbitt, H.W., and Bird, D.K. (1978) Summary and critique of the thermodynamic properties of rock-forming minerals. American Journal of Science, 278A, 1–229.Google Scholar
  17. Hummel, W. (2002) Nagra/PSI Chemical Thermodynamic Database 01/01. Universal-Publishers, Parkland, Florida, USA, 589 pp.Google Scholar
  18. Johnson, C.A. and Glasser, F.P. (2003) Hydrotalcite-like minerals (M2Al(OH)6(CO3)0.5·nH2O, where M = Mg, Zn, Co, Ni) in the environment: Synthesis, characterization and thermodynamic stability. Clays and Clay Minerals, 51, 1–8.CrossRefGoogle Scholar
  19. Khan, A.I. and O’Hare, D. (2002) Intercalation chemistry of layered double hydroxides: Recent developments and applications. Journal of Materials Chemistry, 12, 3191–3198.CrossRefGoogle Scholar
  20. Kovanda, F., Koulousek, D., Cilova, Z., and Hulinski, V. (2005) Crystallization of synthetic hydrotalcite under hydrothermal conditions. Applied Clay Science, 28, 101–109.CrossRefGoogle Scholar
  21. Lippmann, F. (1980) Phase diagrams depicting aqueous solubility of binary mineral systems. Neues Jahrbuch für Mineralogie Abhandlungen, 139, 1–25.Google Scholar
  22. Majzlan, J., Grevel, K.D., and Navrotsky, A. (2003a) Thermodynamics of Fe oxides: Part II. Enthalpies of formation and relative stability of goethite (α-FeOOH), lepidocrocite (γ-FeOOH), and maghemite (γ-Fe2O3). American Mineralogist, 88, 855–859.CrossRefGoogle Scholar
  23. Majzlan, J., Lang, B.E., Stevens, R., Navrotsky, A., Woodfield, B.F., and Boerio-Goates, J. (2003b) Thermodynamics of Fe oxides: Part I. Entropy at standard temperature and pressure and heat capacity of goethite (aα-FeOOH), lepidocrocite (γ-FeOOH), and maghemite (γ-Fe2O3). American Mineralogist, 88, 846–854.CrossRefGoogle Scholar
  24. Miyata, S. (1975) The syntheses of hydrotalcite-like compounds and their structures and physico-chemical properties. Clays and Clay Minerals, 23, 369–375.CrossRefGoogle Scholar
  25. Miyata, S. (1980) Physicochemical properties of synthetic hydrotalcites in relation to composition. Clays and Clay Minerals, 28, 50–56.CrossRefGoogle Scholar
  26. Miyata, S. (1983) Anion-exchange properties of hydrotalcitelike compounds. Clays and Clay Minerals, 31, 305–311.CrossRefGoogle Scholar
  27. Parkhurst, D.L. and Appelo, C.A.J. (1999) User’s guide to PHREEQC (version 2). Pp. 99–4259. US Geological Survey Water Resources Investigations Report.Google Scholar
  28. Prikhod’ko, R.V., Sychev, M.V., Astrelin, I.M., Erdmann, K., Mangel, A., and van Santen, R.A. (2001) Synthesis and structural transformations of hydrotalcite-like materials Mg-Al and Zn-Al. Russian Journal of Applied Chemistry, 74, 1621–1626.CrossRefGoogle Scholar
  29. Rozov, K., Berner, U., Taviot-Gueho, C., Leroux, F., Renaudin, G., Kulik, D., and Diamond, L.W. (2010) Synthesis and characterization of the LDH hydrotalcitepyroaurite solid solution series. Cement and Concrete Research, 40, 1248–1254.CrossRefGoogle Scholar
  30. Trave, A., Selloni, A., Goursot, A., Tichit, D., and Weber, J. (2002) First principles study of the structure and chemistry of Mg-based hydrotalcite-like anionic clays. Journal of Physical Chemistry, 106, 12291–12296.CrossRefGoogle Scholar
  31. Vagvolgyi, V., Palmer, S.J., Kristof, J., Frost, R.L., and Horvath, E. (2008) Mechanism for hydrotalcite decomposition: A controlled rate thermal analysis study. Journal of Colloid and Interface Science, 318, 302–308.CrossRefGoogle Scholar
  32. Vidal, O. and Dubacq, B. (2009) Thermodynamic modelling of clay dehydration, stability and compositional evolution with temperature, pressure and H2O activity. Geochimica et Cosmochimica Acta, 73, 6544–6564.CrossRefGoogle Scholar

Copyright information

© The Clay Minerals Society 2011

Authors and Affiliations

  • K. B. Rozov
    • 1
    • 2
    Email author
  • U. Berner
    • 1
  • D. A. Kulik
    • 1
  • L. W. Diamond
    • 2
  1. 1.Waste Management LaboratoryPaul Scherrer InstituteVilligenSwitzerland
  2. 2.Rock-Water Interaction Group, Institute of Geological SciencesUniversity of BernBernSwitzerland

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