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Microanalysis (Micro-XRF, Micro-XANES, and Micro-XRD) of a Tertiary Sediment Using Microfocused Synchrotron Radiation

Published online by Cambridge University Press:  09 May 2007

Melissa A. Denecke ,
Andrea Somogyi ,
Koen Janssens ,
Rolf Simon ,
Kathy Dardenne  and
Ulrich Noseck
Melissa A. Denecke
Affiliation:
Forschungszentrum Karlsruhe, Institut für Nukleare Entsorgung, P.O. Box 3640, D-76021 Karlsruhe, Germany
Andrea Somogyi
Affiliation:
Synchrotron Soleil, Saint-Aubin—BP 48, F-91192 Gif-sur-Yvette, France
Koen Janssens
Affiliation:
Department of Chemistry, University of Antwerp, Universiteitsplan 1, B-2610 Antwerp, Belgium
Rolf Simon
Affiliation:
Synchrotron Soleil, Saint-Aubin—BP 48, F-91192 Gif-sur-Yvette, France
Kathy Dardenne
Affiliation:
Forschungszentrum Karlsruhe, Institut für Nukleare Entsorgung, P.O. Box 3640, D-76021 Karlsruhe, Germany
Ulrich Noseck
Affiliation:
Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH, Theodor-Heuss-Straße 4, D-38122 Braunschweig, Germany
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Abstract

Micro-focused synchrotron radiation techniques to investigate actinide elements in geological samples are becoming an increasingly used tool in nuclear waste disposal research. In this article, results using μ-focus techniques are presented from a bore core section of a U-rich tertiary sediment collected from Ruprechtov, Czech Republic, a natural analog to nuclear waste repository scenarios in deep geological formations. Different methods are applied to obtain various, complementary information. Elemental and element chemical state distributions are obtained from μ-XRF measurements, oxidation states of As determined from μ-XANES, and the crystalline structure of selected regions are studied by means of μ-XRD. We find that preparation of the thin section created an As oxidation state artifact; it apparently changed the As valence in some regions of the sample. Results support our previously proposed hypothesis of the mechanism for U-enrichment in the sediment. AsFeS coating on framboid Fe nodules in the sediment reduced mobile groundwater-dissolved U(VI) to less-soluble U(IV), thereby immobilizing the uranium in the sediment.

Keywords

micro-XANESmicro-XRFnatural analoguraniumarsenicmicrofocus
Type
SPECIAL SECTION: MICROANALYSIS OF MATERIALS TODAY
Information
Microscopy and Microanalysis , Volume 13 , Issue 3 , June 2007 , pp. 165 - 172
Copyright
© 2007 Microscopy Society of America

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References

REFERENCES

ANKA Instrumentation Book. (2005). Available at http://ankaweb.fzk.de/_file/extras/extras_download_3.pdf.
Denecke, M.A., Friedrich, H., Reich, T., Bernhard, G., Knieß, T., Rettig, D., Zorn, T. & Nitsche, H. (1996). Determination of relative arsenite and arsenate concentrations in aqueous mixtures. In HASYLAB Annual Report, p. 751. Available at: http://hasylab.desy.de/science/annual_reports/index_eng.html.
Denecke, M.A., Janssens, K., Proost, K., Rothe, J. & Noseck, J. (2005). Confocal micro-XRF and micro-XAFS studies of uranium speciation in a tertiary sediment from a waste disposal natural analogue site. Environ Sci Technol 39, 2049–2058.Google Scholar
Hammersley, A.P. (1997). Fit2D code. Available at http://www.esrf.fr/computing/scientific/FIT2D/.
Janssens, K., Proost, K. & Falkenberg, G. (2004). Confocal microscopic X-ray fluorescence at the HASYLAB microfocus beamline: Characteristics and possibilities. Spectrochim Acta B 59, 1637–1645.Google Scholar
Mullen, D.J.E. & Nowacki, W. (1972). Refinement of the crystal structures of realgar, AsS and orpiment, As2S3. Zeitschrift Kristall 136, 48–65.Google Scholar
Nazmov, V., Reznikova, E., Somogyi, A., Mohr, J. & Saile, V. (2004). Planar sets of cross X-ray refractive lenses from SU-8 polymer. In Proceedings of SPIE 2004, vol. 5539, pp. 235–242. Bellingham. WA: SPIE Press.
Noseck, U., Brasser, Th., Raijlich, P., Hercik, M. & Laciok, A. (2004). Mobility of uranium in tertiary argillaceous sediments—A natural analogue study. Radiochim Acta 92, 797–804.Google Scholar
Ressler, T. (1997). WinXAS: A new software package not only for the analysis of energy-dispersive XAS data. J Phys IV 7, C2-269–C2-270.Google Scholar
šmit, Ž., Janssens, K., Proost, K. & Langus, I. (2004). Confocal μ-XRF depth analysis of paint layers. Nucl Instrum Methods Phys Res B 219–220, 35–40.Google Scholar
Somogyi, A., Tucoulou, R., Martinez-Criado, G., Homs, A., Cauzid, J., Bleuet, P., Bohic, S. & Simionovici, A. (2005). ID22: A multitechnique hard X-ray microprobe beamline at the European Synchrotron Radiation Facility. J Synchr Rad 12, 208–215.Google Scholar
Vekemans, B., Janssens, K., Vincze, L., Adams, F. & Van Espen, P. (1994). Analysis of X-ray spectra by iterative least squares (AXIL): New developments. X-Ray Spectrom 23, 278–285.Google Scholar