Experimental electron energy loss spectroscopy of clays

Laboratoire MSSMAT, École Centrale Paris et CNRS UMR 8579, Grande Voie des Vignes, 92295 Châtenay-Malabry, France

Corresponding authors: saoussen.laribi@ensmp.fr bernard.jouffrey@ecp.fr jean-marie.fleureau@ecp.fr

Received: 8 February 2007
Accepted: 19 June 2007
Published online: 12 July 2007

Abstract

The behaviour of clays is not still well understood. Most information concerning clays has been obtained by techniques which give statistical information on the structure and chemistry. However papers have reported results from scanning and high resolution electron microscopy. This work presents a nanoscopic approach, using electron energy loss spectroscopy (EELS), of different purified clays. EELS permitted to detect all the elements found by classical chemistry at a macroscopic level. In particular it made it possible to determine the Si/Al ratio in kaolinite (Si/Al ~ 1), smectite and illite (Si/Al ~ 2). In all the cases, the K edge oxygen energy loss near edge structure (ELNES) is often similar to that of other clays we studied, but a strong heterogeneity has been observed. It was also possible to highlight an influence of the presence of iron on the profile of the oxygen peak.