Deintercalation of hydrazine-intercalated low-defect kaolinite

Ray L. Frost, J. Theo Kloprogge, Janos Kristof, Erzsebet Horvath

Research output: Contribution to journalArticle

25 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)732-741
Number of pages10
JournalClays and Clay Minerals
Volume47
Issue number6
DOIs
Publication statusPublished - Jan 1 1999

Keywords

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

ASJC Scopus subject areas

  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)

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