Deintercalation of hydrazine-intercalated kaolinite in dry and moist air
Frost, Ray L., Kristof, Janos, Kloprogge, J. Theo, & Horvath, Erzsebet (2002) Deintercalation of hydrazine-intercalated kaolinite in dry and moist air. Journal of Colloid and Interface Science, 246(1), pp. 164-174.
The deintercalation of a low defect kaolinite intercalated with hydrazine has been followed by X-ray diffraction, diffuse reflectance infrared spectroscopy (DRIFT) and Raman microscopy over an extended period of time. X-ray diffraction showed the kaolinite was totally intercalated and that more than 120 hours were required for the hydrazine intercalate to be decomposed. The Raman spectra of the hydrazine intercalate showed only a single band at 3620 cm-1 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 occurs the bands assigned to the inner surface hydroxyl groups at 3695, 3682, 3670 and 3650 cm-1 appeared 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. Further, the 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 asymmetric stretching bands observed. Deintercalation was easily 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 new 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 the new band at 3626 cm-1 in the DRIFT spectra.
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|Item Type:||Journal Article|
|Keywords:||Intercalation, hydrazine, kaolinite, hydroxyls, hydrogen bonding, Raman microscopy, X, ray powder diffraction|
|Subjects:||Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > INORGANIC CHEMISTRY (030200)|
|Divisions:||Current > Schools > School of Chemistry, Physics & Mechanical Engineering|
Past > QUT Faculties & Divisions > Faculty of Science and Technology
Current > QUT Faculties and Divisions > Science & Engineering Faculty
|Copyright Owner:||Copyright 2002 Elsevier|
|Copyright Statement:||Reproduced in accordance with the copyright policy of the publisher.|
|Deposited On:||21 Apr 2005|
|Last Modified:||08 Aug 2013 11:48|
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