Fluorine Route Synthesis of Montmorillonites Containing Mg or Zn and Characterization by XRD, Thermal Analysis, MAS NMR, and EXAFS Spectroscopy
✍ Scribed by Marc Reinholdt; Jocelyne Miehé-Brendlé; Luc Delmotte; Marie-Hélène Tuilier; Ronan le Dred; Robert Cortès; Anne-Marie Flank
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 759 KB
- Volume
- 2001
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
EXAFS spectroscopy, combined with X-ray powder diffraction, chemical and thermal analysis, scanning electronic microscopy, 29 Si, 27 Al, and 19 F MAS NMR spectroscopy, are used in the structural analysis of montmorillonites, synthesised in an acidic fluoride medium. Hydrothermal synthesis performed under mild conditions (493 K, autogenous pressure) enables the formation of montmorillonite clays, containing Al and Zn or Mg in the octahedral sheet. It is shown that montmorillonites can only be synthesized in a narrow range of compositions. An accurate value of the Al for Si substitution rate in the tetrahedral sheet is determined by using 27 Al MAS NMR spectroscopy performed under def-