Raman spectroscopy of potassium acetate-intercalated kaolinites over the temperature range 25-300,°C
Frost, Ray L., Kristof, Janos, Horvath, Erzsebet, & Kloprogge, J. Theo (2001) Raman spectroscopy of potassium acetate-intercalated kaolinites over the temperature range 25-300,°C. Journal of Raman Spectroscopy, 32(4), pp. 271-277.
Raman spectra of the hydroxyl-stretching region of potassium acetate-intercalated kaolinite were obtained under an atmosphere of both air and nitrogen using a thermal stage over the temperature range 25-300 °C. At 25 °C, an additional band at 3606 cm-1 attributed to the inner surface hydroxyl hydrogen bonded to the acetate ion is observed with a concomitant loss of intensity in the bands attributed to the inner surface hydroxyls. Heating the intercalated complex to 50 °C results in two hydroxyl-stretching wavenumbers at 3594 and 3604 cm-1. At 100 °C, the bands shift to 3600 and 3613 cm-1. At temperatures from 100 to 300 °C, bands are observed in similar positions. Upon cooling in air to 25 °C, the acetate-bonded inner surface hydroxyl stretching wavenumber shifts back to 3606 cm-1. Upon heating the intercalated kaolinite to 300 °C under an atmosphere of nitrogen and upon cooling the acetate-bonded inner surface hydroxyl stretching wavenumber is observed at 3601 cm-1. Upon cooling to 150 °C and subsequently to 25 °C, two bands are observed at 3611 and 3600 cm-1. Upon rehydration, the hydroxyl stretching wavenumber returns to 3606 cm-1. The changes in the Raman spectra of the hydroxyl-stretching region during dehydration and rehydration are reversible. When the potassium acetate-intercalated kaolinite is heated to 300 °C and cooled to 25 °C, the inner-hydroxyl band is observed at 3630 cm-1. The shift in the wavenumber of the inner hydroxyl band is attributed to the insertion of the potassium ion in the ditrigonal cavity of the siloxane layer.
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|Item Type:||Journal Article|
|Divisions:||Past > QUT Faculties & Divisions > Faculty of Science and Technology|
|Copyright Owner:||Copyright 2001 John Wiley and Sons|
|Deposited On:||17 Jun 2009 22:57|
|Last Modified:||11 Aug 2011 01:19|
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