Hostname: page-component-78c5997874-j824f Total loading time: 0 Render date: 2024-11-15T15:18:24.272Z Has data issue: false hasContentIssue false
  • English
  • Français

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
Get access

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

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

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