Clays and Clay Minerals

, Volume 41, Issue 3, pp 288–296 | Cite as

Modeling of H+ and Cu2+ Adsorption on Calcium-Montmorillonite

  • Markus Stadler
  • Paul W. Schindler


The interaction of H+- and Cu2+-ions with Ca-montmorillonite was investigated in 0.1 mol/dm3 solutions of Ca(CIO4)2 at 298.2 K by Potentiometrie titrations using both glass electrodes (for H+) and ion specific electrodes (for Cu2+ ). The experimental data were interpreted on the basis of the surface complexation model. The calculations were performed with the least-squares program FITEQL (Westall, 1982) using the constant capacitance approximation. The best fit was obtained with a set of equilibria of the general form
$$\begin{array}{c}pH^{+}+qCu^{2+}+\equiv{SOH}\Leftrightarrow(H^{+})_p(Cu^{2+})_q(\equiv{SOH})^{(p+2q)+}\\ \beta_{p,q(int)}^s=\frac{\text[H_pCu_q(\equiv{SOH})^{(p+2q)}]}{\text[H^+]^{p}[Cu^{2+}]^q[\equiv{SOH}]}\end{array}$$
and the constants logβ 1,0(int) S = 8.16 (± 0.04), logβ-1,0(int)S = −8.71 (± 0.08), logβ0,1(int)S = 5.87 (± 0.06), logβ−1,1(int)S = −0.57 (± 0.12), logβ−2,1(int)S = −6.76 (± 0.02). An appropriate modeling of the H+ adsorption data requires the introduction of a second surface group ≡ TOH with the acidity constant
In addition, the ion exchange equilibria Ca2+ − Cu2+ and Ca2+ − H+ had to be taken into account. Arguments are presented to identify the groups ≡ SOH and ≡ TOH as surface aluminol groups =Al(OH)(H2O) and surface silanol groups ≡ Si-OH, respectively.

Key Words

Adsorption Copper Modeling Montmorillonite 


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  1. Baes, C. F., and Mesmer, R. E. (1976) The Hydrolysis of Cations: Wiley Interscience, New York, p. 189.Google Scholar
  2. Banin, A. (1969) Ion exchange isotherms of montmorillonite and structural factors affecting them: Isr. J. Chem. 6, 27–36.CrossRefGoogle Scholar
  3. Benson, L. V. (1982) A tabulation and evaluation of ion exchange data on smectites: Environ. Geol. 4, 23–29.CrossRefGoogle Scholar
  4. Davis, C. W. (1962) Ion association: Butterworths, London.Google Scholar
  5. Davis, J. A. and Kent, D. B. (1990) Surface complexation modeling in aqueous geochemistry: in Mineral-water Interface Geochemistry, M. F. Hochella, Jr. and A. F. White, eds. Reviews in Mineralogy 23, Mineralological Society of America, Washington, D.C., 177–260.CrossRefGoogle Scholar
  6. El-Sayed, M. H., Burau, R. G., and Babcock K. L. (1970) Thermodynamics of copper(II)-calcium exchange on Bentonite clay: Soil Sci. Soc. Am. J. 34, 397–400.CrossRefGoogle Scholar
  7. Eltantawy, I. M. and Arnold, P. W. (1973) Reappraisal of the ethylene glycol mono-ethyl ether (EGME) method for surface area estimations of clays: J. Soil Sci. 24, 232–238.CrossRefGoogle Scholar
  8. Fletcher, P. and Sposito, G. (1989) The chemical modeling of clay/electrolyte interactions for montmorillonite: Clay Miner. 24, 375–391.CrossRefGoogle Scholar
  9. Gaines, G. L. and Thomas, H. C. (1953) Adsorption studies on clay minerals. II. A formulation of the thermodynamics of exchange adsorption: J. Chem. Phys. 21, 714–718.CrossRefGoogle Scholar
  10. Hiemstra, T., Van Riemsdijk, W. H., and Bolt, G. H. (1989) Multisite proton adsorption modeling at the solid/solution interface of (Hydr)oxides: A new approach: J. Colloid Interface Sci. 133, 91–104.CrossRefGoogle Scholar
  11. James, R. O. and Parks, G. A. (1982) Characterization of aqueous colloids by their electrical double-layer and intrinsic surface chemical properties: Surface and Colloid Science, Vol. 12, E. Matijevic, ed., Plenum Publishing Corporation, New York.Google Scholar
  12. King, E. J. (1965) Acid-Base Eauilibria: Pergamon Press, Oxford, 117–128.Google Scholar
  13. Martell, A. E. and Smith, R. M. (1976) Critical Stability Constants, Vol. 4: Inorganic Complexes: Plenum Press, New York and London.Google Scholar
  14. Pulfer, K. (1981) Kinetik und Mechanismus der Auflösung von γ-Al(OH)3 (Bayerit) in HNO3-HF-Lösungen: Ph.D. thesis, University of Berne, Switzerland, # of pp.Google Scholar
  15. Pulfer, K. (1984) Kinetics and mechanism of dissolution of Bayerite (γ-Al(OH)3) in HNO3-HF solutions at 298.2°K: J. Colloid Interface Sci. 101, No. 2, 554–564.Google Scholar
  16. Schindler, P. W. and Gamsjäger H. (1972) Acid-base reactions of the TiO2 (anatase)-water interface and the point of zero charge of TiO2 suspensions: Kolloid Z. und Z. Polymere 250, 759–765.CrossRefGoogle Scholar
  17. Schindler, P. W. and Stumm, W. (1987) The surface chemistry of oxides, hydroxides and oxide minerals: in Aquatic surface chemistry, W. Stumm, ed., Wiley Interscience, New York, 83–110.Google Scholar
  18. Schindler, P. W., Liechti, P., and Westall, J. C. (1987) Adsorption of copper, cadmium and lead from aqueous solution to the kaolinite/water interface: Netherlands J. of Agricultural Science 35, 219–230.Google Scholar
  19. Schindler, P. W. and Sposito, G. (1991) Surface complexation at (hydr)oxide surfaces: in Interactions at the Soil Colloid-Soil Solution Interface, G. H. Bolt, M. F. DeBoodt, M. H. B. Hayes, and M. B. McBride, eds. NATO ASI Series; Series E; Applied Sciences Vol. 190; Kluwer Academic Publishers Dordrecht, Boston, London.Google Scholar
  20. Shaviv, A. and Mattigod, S. V. (1985) Cation exchnge equilibria in soils expressed as cation-ligand complex formation: Soil Sci. Soc. Am. J. 49, 569.CrossRefGoogle Scholar
  21. Sposito, G. (1981) Thermodynamics of Soil Solutions: Oxford Clarendon Press.Google Scholar
  22. Sposito, G., Holtzclaw, K. M., Charlet, L., Jouany, C., and Page, L. (1983) Sodium-Calcium and Sodium-magnesium exchange on Wyoming Bentonite in Perchlorate and chloride background ionic media: Soil Sci. Soc. Am. J. 47, 51–56.CrossRefGoogle Scholar
  23. Sposito, G. (1984) The Surface Chemistry of Soils: Oxford University Press, Oxford.Google Scholar
  24. Westall, J. C. (1987) Adsorption mechanisms in aquatic surface chemistry: in Aquatic Surface Chemistry, W. Stumm, ed., Wiley Interscience, New York, 3–32.Google Scholar
  25. Westall, J. C. (1982) A program for the determination of chemical equilibrium constants from experimental data: User’s Guide vs. 1.2., Oregon State University, Corvallis.Google Scholar

Copyright information

© The Clay Minerals Society 1993

Authors and Affiliations

  • Markus Stadler
    • 1
  • Paul W. Schindler
    • 1
  1. 1.Institute for Inorganic ChemistryUniversity of BerneBerneSwitzerland

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