Chemometric investigation of disorder in kaolinite

Abstract

A series of kaolinites with various degrees of disorder were studied using both infrared absorption and diffuse reflectance infrared spectroscopy coupled with chemometrics. The hydroxyl stretching region of the infrared spectrum of kaolinite from 3550 to 3750 cm^–1 was studied. Typically, disorder determinations examine the 3695 cm^–1 band, but however this work indicates the importance of measurement of all four bands of the hydroxyl stretching region. Principal component analysis was used to separate the kaolinites with higher disorder from those with low disorder, through either principal component one or two, depending on the spectral method employed. Chemometrics provides a new means of quantifying the disorder of kaolinites based on the use of the infrared spectrum of the hydroxyl stretching region.