Kinetics of deintercalation of potassium acetate from kaolinite - a Raman spectroscopic study

The kinetics of structural change of a highly ordered kaolinite intercalated with potassium acetate have been studied through both intercalation and deintercalation. Deintercalation of the intercalated kaolinite, brought about by washing for different time intervals was followed by both X-ray diffraction and Raman microscopy. X-ray diffraction shows the kaolinite to be highly ordered with a Hinckley index of 1.42 and intercalated to similar to 90%. X-ray diffraction also showed that the intercalated kaolinite was deintercalated by 80% in the first minute of washing. An additional Raman band, attributed to the inner surface hydroxyl groups, strongly hydrogen bound to the acetate, is observed at 3605 cm(-1) for the potassium acetate intercalate with the concomitant loss of intensity in the bands at 3652, 3670, 3684 and 3693 cm(-1). Upon deintercalation, the intensity of the 3605 cm-l band decreased as the 3695 cm(-1) band increased. The Raman spectral changes brought about upon deintercalation mirrored the changes observed by X-ray diffraction. Deintercalation of kaolinite caused disordering of the kaolinite.