{sup 133}Cs NMR and XPS investigation of cesium adsorbed on clay minerals and related phases
- Univ. of Illinois, Urbana, IL (United States)
- Sandia National Laboratories, Albuquerque, NM (United States)
{sup 133}Cs MAS NMR and Cs XPS were used to study the adsorption of Cs on kaolinite, montmorillonite, corundum, and gibbsite from 0.1 N and 0.01 N CsCl solutions. XPS spectra for all samples except gibbiste contain strong signals associated with Cs 3d{sub 3/2} and 3d{sub 5/2} photopeaks. This result indicates that minerals without exchangeable cation sites have a tendency to sorb Cs on surfaces and along grain boundaries, although less than 1 mol% Cs is observed on these surfaces. Multiple surface or interlayer sites for Cs cannot be resolved from the individual Cs XPS peaks. The {sup 133}Cs NMR data, combined with TEM/XRD data for kaolinite show the following: (1) For montmorillonite, most of the Cs is adsorbed in the interlayers and at room humidity is motionally averaged among two or more sites at room temperature. (2) The spectra for kaolinite are similar to those of montomorillonite, and the tightly bonded Cs in our sample appears to be in expandable interlayers which exits as mixed layers with kaolinite and not as discrete smectite. (3) The Cs environments in both montmorillonite and kaolinite are sensitive to humidity. (4) For kaolinite the {sup 133}Cs chemical shift changes at low temperature and 100% humidity, indicating that the interlayer charge of its expandable layers is very small. (5) No {sup 133}Cs NMR signal could be detected for gibbsite or corundum. {sup 133}Cs NMR may be a useful probe of the presence and characteristics of expandable layers in kaolinite. 62 refs., 14 figs.
- Research Organization:
- Sandia National Laboratory
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 281140
- Journal Information:
- Geochimica et Cosmochimica Acta, Journal Name: Geochimica et Cosmochimica Acta Journal Issue: 6 Vol. 60; ISSN GCACAK; ISSN 0016-7037
- Country of Publication:
- United States
- Language:
- English
Similar Records
{sup 23}Na and {sup 133}Cs NMR study of cation adsorption on mineral surfaces: Local environments, dynamics, and effects of mixed cations
{sup 133}Cs NMR study of cesium on the surfaces of kaolinite and illite