Deintercalation of Hydrazine-Intercalated Low-Defect Kaolinite

Ray L. Frost1, J. Theo Kloprogge1, Janos Kristof2 and Erzsebet Horvath3
1 Centre for Instrumental and Developmental Chemistry, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Q 4001, Australia
2 Department of Analytical Chemistry, University of Veszprem, H 8201 Veszprem, PO Box 158, Hungary
3 Research Group for Analytical Chemistry, Hungarian Academy of Sciences, H 8201 Veszprem, PO Box 158, Hungary
E-mail of corresponding author:

Abstract: The deintercalation of a low-defect kaolinite intercalated with hydrazine was studied by X-ray diffraction, diffuse reflectance infrared spectroscopy (DRIFT), and Raman microscopy over 30 d. X-ray diffraction showed that the kaolinite was fully intercalated. More than 120 h were required for the hydrazine-intercalate to decompose. The Raman spectra of the hydrazine intercalate showed only a single band at 3620 cm−1, which was attributed to the inner-hydroxyl group. Upon deintercalation, additional Raman bands were observed at 3626 and 3613 cm−1. These bands decreased in intensity with further deintercalation. As deintercalation proceeded, the bands assigned to the inner-surface hydroxyl groups at 3695, 3682, 3670, and 3650 cm−1 occurred and increased in intensity. DRIFT spectra showed two bands at 3620 and 3626 cm−1 for the fully intercalated kaolinite only. Upon deintercalation, an additional band assigned to intercalated water was observed at 3599 cm−1 and increased in intensity at the expense of the 3626-cm−1 band. Bands attributed to the inner-surface hydroxyl groups increased in intensity with deintercalation. Both the Raman and DRIFT spectra showed complexity in the NH-stretching region with two sets of NH-symmetric and antisymmetric stretching bands. Deintercalation was followed by the loss of intensity of these bands. Significant changes were also observed in the hydroxyl deformation and water-bending modes as a result of deintercalation. A model of hydrazine intercalation of kaolinite based on the insertion of a hydrazine-water unit is proposed. The hydrated end of the hydrazine molecule hydrogen bonds with the inner-surface hydroxyl groups resulting in the formation of a band at 3626 cm−1 in the DRIFT spectra.

Key Words: Hydrazine • Hydrogen Bonding • Hydroxyl Groups • Intercalation of Kaolinite • Powder X-ray Diffraction • Raman Microscopy

Clays and Clay Minerals; December 1999 v. 47; no. 6; p. 732-741; DOI: 10.1346/CCMN.1999.0470607
© 1999, The Clay Minerals Society
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