X-ray absorption studies of uranium sorption on mineral substrates

Book · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:99502

Hudson, E A; Terminello, L J; Viani, B E ^[1]; Reich, T ^[2]; Bucher, J J; Shuh, D K; Edelstein, N M ^[3]

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1. Lawrence Livermore National Lab., CA (United States)
2. Forschungszentrum Rossendorf e.V., Dresden (Germany). Institut fuer Radiochemie
3. Lawrence Berkeley Lab., CA (United States)

Aqueous transport of actinides in the geosphere can be significantly retarded by sorption and/or precipitation upon mineral surfaces. Despite the importance of this effect to environmental remediation efforts and nuclear waste repository design, there is only limited direct knowledge about the microscopic nature of the actinide-mineral interaction. Here, uranium L{sub 3}-edge x-ray absorption spectra have been measured for uranium-mineral sorption systems. An expansible layer silicate, vermiculite, was treated to obtain a collapsed phase, thereby limiting access to the interior cation exchange sites. Samples were prepared by exposing the finely powdered mineral, in the natural and modified form, to aqueous solutions of uranyl chloride. EXAFS spectra of the encapsulated samples were measured at the Stanford Synchrotron Radiation Laboratory. Results indicate that the uranyl ion possesses a more symmetric local structure for the natural vermiculite than for the collapsed form, suggesting structural differences between uranyl species within the interlayer regions of vermiculite and on the external surfaces.

• DOE Contract Number: W-7405-ENG-48; AC03-76SF00098
• OSTI ID: 99502
• Report Number(s): CONF-941144--; ISBN 1-55899-277-4
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
36 MATERIALS SCIENCE
CLATHRATES
DEBYE-WALLER FACTOR
EXPERIMENTAL DATA
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE FACILITIES
REMEDIAL ACTION
SORPTION
SORPTIVE PROPERTIES
URANIUM
VERMICULITE