Cs–sorption in weathered biotite from Fukushima granitic soil

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Author(s)

    • KIKUCHI Ryosuke
    • Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo
    • MUKAI Hiroki
    • Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo
    • KURAMATA Chisaki
    • Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo
    • KOGURE Toshihiro
    • Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo

Abstract

The sorption characteristics of cesium (Cs) ions into weathered biotite with biotite–vermiculite interstratification collected from weathered granodiorite in Fukushima Prefecture, Japan has been investigated. Both single crystals and crushed powder forms of the weathered biotite were experimentally reacted with 20–2000 ppm CsCl aqueous solutions, and analyzed by powder X–ray diffraction (XRD), scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) to examine the distribution of Cs inside the crystals. From the XRD pattern, the proportion of vermiculite unit layers in the weathered biotite was estimated at ~ 12%, with a tendency for segregation, and the whole XRD pattern was explained by the coexistence of biotite and vermiculite packets as well as the interstratified regions. Powder XRD of Cs–sorbed specimens showed that the 14.9 Å peak of the vermiculite packets was weakened at a low Cs concentration in the solution. Single crystals of the weathered biotite with a polished edge–surface were immersed in the CsCl solutions and examined using SEM and high–angular annular dark field (HAADF) imaging in STEM. Cs was not only incorporated in the vicinity of the exposed surface but also penetrated deeply inside the crystals. These analyses and observations revealed the Cs–sorption process in weathered biotite. At first, Cs preferentially replaced specific vermiculite interlayers in the vermiculite packets. With a higher Cs concentration in the solution, the Cs–substituted vermiculite interlayers increased in the vermiculite packets, and vermiculite layers interstratified in biotite also incorporated Cs.

Journal

  • Journal of Mineralogical and Petrological Sciences

    Journal of Mineralogical and Petrological Sciences 110(3), 126-134, 2015

    Japan Association of Mineralogical Sciences

Codes

  • NII Article ID (NAID)
    130005083499
  • Text Lang
    ENG
  • ISSN
    1345-6296
  • Data Source
    J-STAGE 
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