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Journal of Colloid and Interface Science

Horváth

et al. 2002

Controlled rate thermal analysis (CRTA) allows the separation of adsorbed and intercalated hydrazine. CRTA displays the presence of three different types of hydrogen-bonded hydrazine in the intercalation complex (a) adsorbed loosely bonded on the kaolinite structure fully expanded by hydrazine-hydrate and liberated between approx. 50 and 70°C (b) The second intercalated-hydrazine is lost between approx. 70 and 85°C, (c) The third type of intercalated-hydrazine molecule is lost in the 85-130°C range. CRTA at 70 °C enables the removal of hydrazine-water and results in the partial collapse of the hydrazine-intercalated kaolinite structure to form a hydrazine-intercalated kaolinite. Removal of the adsorbed hydrazine enables the DRIFT spectra of the hydrazine-intercalation complex. A band at 3626 cm -1• Author to whom correspondence should be addressed (r.frost@qut.edu.au) 2 attributed to the inner surface hydroxyls of kaolinite hydrogen bonded to the hydrazine is observed. The intercalation of hydrazine-hydrate into kaolinite is complex and results from the different types of surface interactions of the hydrazine with the kaolinite surfaces.

Section: Intercalation Of Kaolinitementioning

confidence: 99%

“…New thermoanalytical techniques, which can separate thermal processes, have been developed. (7,9,13). Under controlled rate conditions, i.e.…”

Section: X-ray Diffractionmentioning

confidence: 99%

Section: X-ray Diffractionmentioning

confidence: 99%

mentioning

confidence: 99%

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Complexity of Intercalation of Hydrazine into Kaolinite—A Controlled Rate Thermal Analysis and DRIFT Spectroscopic Study

Journal of Colloid and Interface Science

Horváth

et al. 2002

“…The interaction of the N is not expected to be as strong as that of potassium acetate and vibrational spectroscopic bands higher than 3605 cm −1 are predicted. The interaction of the H in the hydrazine-intercalation complex is expected to be similar to that of the hydrogens in urea (8)(9)(10)(11). Thus, there would be no additional hydroxyl bands and no decrease in the intensities of the inner-surface hydroxyls.…”

Section: Introductionmentioning

confidence: 98%

Deintercalation of Hydrazine-Intercalated Kaolinite in Dry and Moist Air

Journal of Colloid and Interface Science

Kloprogge

et al. 2002

The deintercalation of hydrazine-intercalated kaolinite has been followed using a combination of X-ray diffraction and diffuse reflectance Fourier transform infrared spectroscopy. Upon intercalation of the kaolinite with hydrazine, the kaolinite layers are expanded to 10.66 A and remain expanded for up to 22 h upon exposure to moist air. Only upon deintercalation are the peak at 10.39 A and a minor peak at 9.6 A observed. Complete deintercalation takes up to 18 days more. Upon intercalation with hydrazine an intense band is observed at 3628 cm(-1) and is attributed to the inner-surface hydroxyls hydrogen bonded to the hydrazine, which upon deintercalation decreased in intensity. This rate of deintercalation is affected by the presence or absence of moist air. Deintercalation in the presence of water vapor results in the observation of two additional bands at 3550 and 3598 cm(-1), which are attributed to the hydroxyl stretching modes of adsorbed water during deintercalation. The intensity of NH stretching vibrations observed at 3360, 3300, and 3200 cm(-1) also decrease in intensity with deintercalation time. Changes in the hydroxyl deformation modes of kaolinite in the 915 cm(-1) region and in the HNH deformation modes show strong interactions between the kaolinite surface and the inserting hydrazine molecule.

Raman microscopy of formamide‐intercalated kaolinites treated by controlled‐rate thermal analysis technology

Horváth

et al. 2001

J Raman Spectroscopy

Raman spectroscopy of formamide-intercalated kaolinites treated using controlled-rate thermal analysis technology (CRTA), allowing the separation of adsorbed formamide from intercalated formamide in formamide-intercalated kaolinites, is reported. The Raman spectra of the CRTA-treated formamideintercalated kaolinites are significantly different from those of the intercalated kaolinites, which display a combination of both intercalated and adsorbed formamide. An intense band is observed at 3629 cm −1 , attributed to the inner surface hydroxyls hydrogen bonded to the formamide. Broad bands are observed at 3600 and 3639 cm −1 , assigned to the inner surface hydroxyls, which are hydrogen bonded to the adsorbed water molecules. The hydroxyl-stretching band of the inner hydroxyl is observed at 3621 cm −1 in the Raman spectra of the CRTA-treated formamide-intercalated kaolinites. The results of thermal analysis show that the amount of intercalated formamide between the kaolinite layers is independent of the presence of water. Significant differences are observed in the C O stretching region between the adsorbed and intercalated formamide.