ENERGETIC SURFACE HETEROGENEITY OF ILLITES AND KAOLINITES

The surface properties of six clay samples (three illites and three ka olinites formed under different logical conditions) were evaluated by inverse gas chromatography at finite concentration conditions. The det ermination of the adsorption isotherms for several organic probes, hex ane, benzene, pyridine, and 2-propanol, on these clays allows the esti mation of their energetic surface heterogeneity through the determinat ion of their adsorption energy distribution functions. It was then sho wn that, when the organic probe is well chosen, this method allows dis tinguishing between the family of clay, illite or kaolinite, and even, in a same family, between the different geological formation conditio ns. The illite samples are more heterogeneous than the kaolinite sampl es.