Clays and Clay Minerals

, Volume 42, Issue 5, pp 634–642 | Cite as

Redox Treatment of an Fe/Al Pillared Montmorillonite. A Mössbauer Study

  • T. Bakas
  • A. Moukarika
  • V. Papaefthymiou
  • A. Ladavos


Pillared structures with an interlayer opening of ∼0.3 nm were obtained after successive heat treatments of the PILC precursor in reducing and oxidizing conditions. This precursor was prepared by reacting a Na+-montmorillonite with an intercalant containing Al and Fe oxo-hydroxides (Al/Fe = 1). Powder X-ray diffraction, elemental analysis, 57Fe Mössbauer spectroscopy, catalytic activity measurements and surface area data were used to characterize the samples. On the basis of Mössbauer spectra taken at temperatures between 4.2 and 300 K, it is deduced that oxidizing steps produce Al substituted maghemite which converts into Al substituted magnetite upon reducing heat treatment. Firing the precursor in oxidizing atmosphere forms pillars of few nm in diameter. However, heating under reducing conditions yields pillars of smaller diameter. This later behaviour is maintained even after reheating the material in oxidizing atmosphere. From the temperature dependence of Mössbauer spectra it is deduced that the diameter of the Fe oxide particles in the pillars is smaller than 10 nm.

Key Words

Lepidocrocite Maghemite Magnetite Modified montmorillonite Mössbauer PILC Superparamagnetism 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Annersten, H. and Hafner, S. S. (1973) Vacancy distribution in synthetic spinels of the series Fe3O4-γ-Fe2O3: Z Kris-tallogr. 137: 321–340.Google Scholar
  2. Bartley, G. J. J. (1988) Zirconium pillared clays: Catal. Today 2: 233–241.CrossRefGoogle Scholar
  3. Bergaya, F. and Barrault, J. (1990) Mixed Al-Fe pillared laponites: Preparation characterization and their catalytic properties in syngas conversion: in Pillared Layered Structures: Current Trends and Applications: I. V. Mitchell, ed., Commission of European Communities, Elsevier Applied Science, London, 167–184.Google Scholar
  4. Bergaya, F., Hassoun, N., Gatineau, L., and Barrault, J. (1991) Mixed Al-Fe pillared laponites: Preparation, characterization and catalytic properties in syngas conversion: in Preparation of Catalysts V: G. Poncelet, P. A. Jacobs, P. Grange, and B. Delmon, eds., Elsevier Science Publishers B. V., Amsterdam, 329–337.Google Scholar
  5. Bergaya, F., Hassoun, N., Barrault, J., and Gatineau, L. (1993) Pillaring of synthetic hectorite by mixed [Al13−xFex] pillars: Clay Miner. 28: 109–122.CrossRefGoogle Scholar
  6. Braddell, O., Barklie, R. C., Doff, D. H., Gangas, N. H. J., and McKimm, A. (1987) EPR of Cu2+ ions in pillared clay: Zeit. Phys. Chem. 151: 157–164.CrossRefGoogle Scholar
  7. Brindley, G. W. and Sempels, R. E. (1977) Preparation and properties of some hydroxy-aluminiun beidellites: Clay Miner. 12: 229–236.CrossRefGoogle Scholar
  8. Coey, J. M. D. (1980) At. Energy Rev.. 18. no. 1. 73–124.Google Scholar
  9. Christiano, S. P. and Pinnavaia, T. J. (1986) Intercalation in montmorillonite of molybdenum cations containing the Mo6Clg cluster core: J. Solid State Chem. 64: 232–239.CrossRefGoogle Scholar
  10. Christiano, S. P., Wang, J., and Pinnavaia, T. J. (1985) Intercalation of Niobium and Tantalum M6Cl12n+ cluster cations in montmorillonite: A new route to pillared clays: Inorg. Chem. 24: 1222–1227.CrossRefGoogle Scholar
  11. De Grave, E., Bowen, L. H., and Weed, S. B. (1982) Moss-bauer study of Aluminum-substituted hematites: J. Mag. Mag. Mat. 27: 98–108.CrossRefGoogle Scholar
  12. De Villiers, J. M. and van Rooyen, T. H. (1967) Solid solution formation of lepidocrocite-boehmite and its occurrence in soil: Clay Miner. 7: 229–235.CrossRefGoogle Scholar
  13. Doff, D. H., Gangas, N. H. J., Allan, J. E. M., and Coey, J. M. D. (1988) Preparation and characterization of iron oxide pillared montmorillonite: Clay Miner. 23: 367–377.CrossRefGoogle Scholar
  14. Dormann, J. L., Seqqat, M., Fiorani, D., Nogues, M., Soubey-roux, J. L., Bhargava, S. C., and Renaudin, P. (1990) Mössbauer studies of FeAl2O4 and FeIn2S4 spin glass spinels: Hyper. Inter. 54: 503–508.CrossRefGoogle Scholar
  15. Endo, T., Mortland, M. M., and Pinnavaia, T. J. (1980) Intercalation of silica in smectites: Clays & Clay Minerals 28:105–110.CrossRefGoogle Scholar
  16. Fripiat, J. J. (1986) Internal surface of clays and constrained chemical reactions: Clays & Clay Minerals 34: 501–506.CrossRefGoogle Scholar
  17. Gangas, N. H. J., van Wonterghem, J., Morup, S., and Koch, C. J. W. (1985) Magnetic bridging in nontronite by intercalated iron: J. Phys. C. 18. L1011–L1015.CrossRefGoogle Scholar
  18. Gangas, N. H., Bakas, T., Moukarika, A., Petrides, D., and Simopoulos, A. (1987) Magnetic ordering in nontronite pillared with Al-polyoxo cations: NATO ASI Chemical Physics of Intercalation, Castera-Verduzan, France.Google Scholar
  19. Harsh, J. B. and Doner, H. E. (1984) Specific adsorption of copper on an hydroxy-aluminium-montmorillonite complex: Soil Sci. Am. Proc. 48: 1034–1039.CrossRefGoogle Scholar
  20. Karydas, A. G. and Paradellis, T. (1990) Coal XRF analysis using a proton induced copper X-ray beam: J. Coal Qual.. 9. no. 2. 39–43.Google Scholar
  21. Lahav, N., Shani, U., and Shabtai, J. (1978) Cross-linked smectites. I—Synthesis and properties of hydroxy-alumi-num-montmorillonite: Clays & Clay Minerals 26:107–115.CrossRefGoogle Scholar
  22. Longworth, G. (1984) Spectral data reduction and refinement: in Mössbauer Spectroscopy Applied to Inorganic Chemistry, Vol. 1, G. J. Long, ed., Plenum Press, New York and London, 43–56.CrossRefGoogle Scholar
  23. Lee Woo, Y. Raythatha, R. H., and Tatarchuk, B. J. (1989) Pillared-Clay Catalysts Containing Mixed-Metal Complexes: J. Catal. 115: 159–179.CrossRefGoogle Scholar
  24. Mitchell, I. V. (1990) ed. Pillared Layered Structures. Current Trends and Applications: Commission of European Communities, Elsevier Applied Science, London, 209–217.Google Scholar
  25. Morup, S. (1987) Mössbauer effect studies of microcrystal-line materials: in Mössbauer Spectroscopy Applied to Inorganic Chemistry, Vol. 2, G. J. Long, ed., Long, Plenum Press, New York and London, 89–119.Google Scholar
  26. Morup, S., Dumesic, J. A., and Topsoe, H. (1980) Magnetic microcrystals: in Applications of Mössbauer Spectroscopy, Vol. 2, R. Cohen, ed., Academic Press, New York.Google Scholar
  27. Murad, E. and Johnston, H. J. (1987) Iron oxides and hydroxides: in Mössbauer Spectroscopy Applied to Inorganic Chemistry, Vol. 2, G. J. Long, ed., Plenum Press, New York and London. 507–574.Google Scholar
  28. Occelli, M. L. (1983) Catalytic cracking with an interlayered clay. A two-dimensional molecular sieve: Ind. Eng. Chem. Prod. Res. Dev. 22: 553–559.CrossRefGoogle Scholar
  29. Petridis, D., Bakas, T., Simopoulos, A., and Gangas, N. H. 1989. Pillaring of montmorillonite by organotin cationic complexes: Inorg. Chem. 28: 2439–2443.CrossRefGoogle Scholar
  30. Pinnavaia, T. J. (1983) Intercalated clay catalysts: Science 220: 365–371.CrossRefGoogle Scholar
  31. Pinnavaia, T. J., Rainey, V., Ming-Shin Tzou, and White, J. W. (1984) Characterization of pillared clays by neutron scattering: J. Mol. Catal. 27: 213–224.CrossRefGoogle Scholar
  32. Plee, D., Borg, F., Gatineau, L., and Fripiat, J. J. (1985) High resolution solid state 27Al and 29Si nuclear magnetic resonance study of pillared clays: J. Amer. Chem. Soc. 107: 2362–2369.CrossRefGoogle Scholar
  33. Rozenson, I. and Heller-Kallai, L. (1976) Reduction and oxidation of Fe3+ in dioctahedral smectites— 1. Reduction with hydrazine and dithionite: Clays & Clay Minerals 24: 271–282.CrossRefGoogle Scholar
  34. Sa vidou, A. and Paradellis, T. (1990) Determination of light elements in a natural coal sample by PIGE spectroscopy: J. Coal Qual.. 9. no. 2. 45–47.Google Scholar
  35. Simopoulos, A., Kostikas, A., Sigalas, I., Gangas, N. H., and Moukarika, A. (1975) Mössbauer study of transformations induced in clays by firing: Clays & Clay Minerals 23: 393–399.CrossRefGoogle Scholar
  36. Sterte, J. (1986) Synthesis and properties of titanium oxide cross-linked montmorillonite: Clays & Clay Minerals 34: 658–664.CrossRefGoogle Scholar
  37. Takada, T., Kiyama, M., Bando, Y., Nakamura, T., Shiga, M., Shinjo, T., Yamamoto, N., Endoh, Y., and Takaki, H. (1964) Mössbauer study of a-, ß-, and γ-FeOOH: J. Phys. Soc. Japan. 19. 1744.CrossRefGoogle Scholar
  38. Terashima, T. and Bando, Y. (1985) Magnetism of ultrathin Fe3O4 films: J. Phys. Soc. Japan. 54. no. 10. 3920–3924.CrossRefGoogle Scholar
  39. Tzou, M. S. and Pinnavaia, T. J. (1988) Chromia pillared clays: Catal. Today 2: 243–259.CrossRefGoogle Scholar
  40. Tillak, D., Tennakoon, B., Jones, W., and Thomas, J. M. (1986) Structural aspects of metal-oxide-pillared sheet silicates: J. Chem. Soc, Faraday Trans. 182: 3081–3095.Google Scholar
  41. Vaughan, D. E. W. (1988) Recent developments in pillared interlayered clays: in Perspectives in Molecular Sieve Science, ACS Symposium Series 368: 308–323.CrossRefGoogle Scholar
  42. Vaughan, D. E. W. and Lussier, R. J. (1980) Preparation of molecular sieves based on pillared interlayered clays: in Proc. 5th International Conference on Zeolites, Naples, L. V. C. Rees, ed., Heyden, London, 94–101.Google Scholar
  43. Voorhoeve, R. J. H. and Trimble, L. E. (1975) Reduction of nitric oxide with carbon monoxide and hydrogen over Ruthenium catalysts: J. Catal. 38: 80–91.CrossRefGoogle Scholar
  44. Yamanaka, S., Doi, T., Sako, S., and Hattori, M. (1984) High surface area solids obtained by intercalation of iron oxide pillars in montmorillonite: Mat. Res. Bul.. 19. 161–168.CrossRefGoogle Scholar

Copyright information

© The Clay Minerals Society 1994

Authors and Affiliations

  • T. Bakas
    • 1
  • A. Moukarika
    • 1
  • V. Papaefthymiou
    • 1
  • A. Ladavos
    • 2
  1. 1.Physics DepartmentThe University of IoanninaIoanninaGreece
  2. 2.Chemistry DepartmentThe University of IoanninaIoanninaGreece

Personalised recommendations