Mineral-specific sorption of Cs, Ni, Eu and Am on granodiorite and mica gneiss

Esa Puukko, Eini Puhakka, Anatero Lindberg, Markus Olin, Martti Hakanen, Jarmo Lehikoinen

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    Abstract

    The contribution of the University of Helsinki (HU) and VTT, Technical Research Centre of Finland, to FUNMIG WP 1.2 focuses on the sorption of nickel and europium on selected rock types in the area of the planned repository. Mechanistic understanding of the interaction of solutes and rock forming minerals is important because fracture surface minerals may be in a very thin layer or absent in reducing bed rock conditions. The specific objective of the work is to interpret from experimental data and molecular modelling of minerals the chemical reactions governing the sorption of Ni(II) and Eu(III) as well as their sorption kinetics and reversibility using well-established thermodynamic sorption models. In this report, the selection of mineral phases for further sorption experiments is described. The work was concentrated on phyllosilicates (e.g. biotite) and tectosilicates (e.g. plagioclase) typical for the bedrock of coastal regions of the Baltic Sea. Experiments were carried out to identify the important minerals for sorption. The methods used for evaluation of the mica gneiss and granodiorite were optical microscopy for mineral contents of the samples and thin section autoradiography of Ni-63, Cs-134, Eu-152 and Am-241 to identify the minerals on which the radionuclides were mainly sorbed. Biotite was the mineral chosen for the experiments. Modelling techniques were utilised in order to obtain an insight of minerals on the molecular level. The starting point for the modelling studies was the crystallographic structures of eight minerals: biotite, chlorite, cordierite, epidote, K-feldspar, muscovite, plagioclase and sillimanite.
    Original languageEnglish
    Title of host publication1st Annual Workshop Proceedings of Integrated Project Fundamental Processes of Radionuclide Migration IP FUNMIG
    Place of PublicationParis
    Pages80-85
    Publication statusPublished - 2006
    MoE publication typeA4 Article in a conference publication
    Event1st Annual Workshop of Integrated Project "Fundamental processes of Radionuclide Migration"(IP FUNMIG) - Paris, France
    Duration: 28 Nov 20051 Dec 2005

    Publication series

    SeriesRapport
    NumberCEA-R-6122
    ISSN0429-3460

    Conference

    Conference1st Annual Workshop of Integrated Project "Fundamental processes of Radionuclide Migration"(IP FUNMIG)
    CountryFrance
    CityParis
    Period28/11/051/12/05

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    Keywords

    • biotite
    • surface complexation modelling

    Cite this

    Puukko, E., Puhakka, E., Lindberg, A., Olin, M., Hakanen, M., & Lehikoinen, J. (2006). Mineral-specific sorption of Cs, Ni, Eu and Am on granodiorite and mica gneiss. In 1st Annual Workshop Proceedings of Integrated Project Fundamental Processes of Radionuclide Migration IP FUNMIG (pp. 80-85). Rapport, No. CEA-R-6122