Local environment of iron and uranium ions in vitrified iron phophate glasses studied by Fe K and U L{sub}III-edge x-ray absorption fine structure spectroscopy.
The local structure of iron and uranium ions in a series of iron phosphate glasses with the general composition (40 - x)Fe{sub 2}O{sub 3-x}UO{sub 2}-60P{sub 2}O{sub 5} and (1-x-y)(40Fe{sub 2}O{sub 3}-60P{sub 2}O{sub 5})-xUO{sub 2-y}(Na{sub 2}O or CaO) was investigated using Fe K-edge and U L{sub III}-edge x-ray absorption fine structure spectroscopy. Replacing Fe{sub 2}O{sub 3} by UO{sub 2} in the glass caused more distortion in the coordination environment of Fe(III) ions. Extended x-ray absorption fine structure fits revealed that the Fe-P bonds observed in the base glass also existed in all the waste-loaded glasses. X-ray absorption near-edge structure showed that the uranium ions were predominantly present as U(IV) in the glasses. Uranium ions were coordinated to approximately 8 {+-} 1 oxygen atoms and 2.5 {+-} 0.6 phosphorus atoms at an average distance of 2.47 {+-} 0.02 and 3.8 {+-} 0.02 {angstrom}, respectively. There were no Fe-U or U-Fe neighbors observed, indicating that uranium ions occupied voids in the glass away from the PO{sub 4} units. These conclusions were supported by Moessbauer, x-ray photoelectron, and Raman spectroscopic data.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 943163
- Report Number(s):
- ANL/MSD/JA-37943; JMREEE; TRN: US1000566
- Journal Information:
- J. Mater. Res., Vol. 15, Issue 9 ; Sep. 2000; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- ENGLISH
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