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Selenium uptake onto natural pyrite

Curti, Enzo ; Aimoz, Laure ; Kitamura, Akira

In: Journal of Radioanalytical and Nuclear Chemistry, 2013, vol. 295, no. 3, p. 1655-1665

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    Titre
    • Selenium uptake onto natural pyrite
    Auteur
    • Curti, Enzo. Laboratory for Waste Management, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
    • Aimoz, Laure. Laboratory for Waste Management, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
    • Kitamura, Akira. Laboratory for Waste Management, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Journal of Radioanalytical and Nuclear Chemistry, 2013, vol. 295, no. 3, p. 1655-1665. Springer Netherlands
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:320576
    Summary
    79Se is a major dose-determining redox-sensitive nuclide in safety analysis of radioactive waste disposal sites. In aqueous solutions, selenium forms soluble anionic species (SeIVO3 2− and SeVIO4 2−) that hardly sorb on negatively charged surfaces of common host-rock minerals. However, Se is known to have a strong affinity with sulphides and interacts with pyrite, a common minor mineral of argillaceous rocks being considered as host formations for radioactive waste repositories. In this study, we present micro- and bulk X-ray spectroscopy data (μ-XRF, μ-XANES, and EXAFS) showing that, under nearly anoxic conditions, dissolved SeO3 2− and SeO4 2− sorb directly onto the pyrite surface and are subsequently reduced to Se0 with increasing ageing time (up to 8months). These results suggest that the mobility of 79SeIV released from radioactive waste could greatly decrease through uptake on the pyrite surface followed by transformation into a sparingly soluble reduced form