Migration of Cu Ions in Cu Montmorillonite Heated With and Without Alkali Halides

L. Heller-Kallai1 and C. Mosser2
1 Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
2 Centre de Geochemie de la Surface, 1 rue Blessig, 67084 Strasbourg Cedex, France

Abstract: Cu montmorillonite heated with or without potassium halide was studied by IR and ESR spectroscopy, supplemented by XRD measurements, microprobe and chemical analyses. It appears that on heating Cu montmorillonite, most of the Cu ions migrate into hexagonal cavities and eventually, when dehydroxylation occurs, into octahedral vacancies. Some Cu ions may penetrate into octahedral vacancies before dehydroxylation. In the presence of potassium halide, deprotonation facilitates penetration of Cu into octahedral vacancies. The presence within the layers of non-exchangeable Cu ions that are inaccessible to water does not necessarily cause the perturbation of OH bending vibrations conventionally attributed to migration of small cations into the structure. Such perturbation was only observed when the basal spacing was reduced to ∼9.5Å.

Key Words: Cu-montmorillonite • K-halide • IR and ESR spectra

Clays and Clay Minerals; December 1995 v. 43; no. 6; p. 738-743; DOI: 10.1346/CCMN.1995.0430610
© 1995, The Clay Minerals Society
Clay Minerals Society (www.clays.org)