Measurements of Eh and pH in compacted MX-80 bentonite

Torbjörn Carlsson, Arto Muurinen

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

    Abstract

    The low-content free water and high swelling pressure in compacted bentonite, planned to be used as a buffer in nuclear waste repositories, create adverse conditions for direct measurements of the chemical conditions. This paper presents laboratory results from online measurements with Eh and pH electrodes in water-saturated compacted MX-80 bentonite. The Eh was measured with Au and Pt wires as electrodes, while the pH was determined with IrOx electrodes. The latter were prepared in accordance with the method by Yao et al. [1]. The measurements were carried out in two types of cells: 'squeezing cells' and 'diffusion cells'. The squeezing cell excludes almost completely all chemical interactions between the sample and the surrounding environment outside the cell. The diffusion cell, on the other hand, contains a sample that stays in contact with an external solution and therefore allows following of the physico-chemical interaction between the sample and the external solution. The measuring electrodes were positioned inside the cell in the compacted bentonite, while the reference electrode was positioned outside the cell.
    Original languageEnglish
    Title of host publicationSymposium NN - Scientific Basis for Nuclear Waste Management XXX
    Place of PublicationWarrendale, PA, USA
    PublisherMaterials Research Society
    Pages533 - 540
    DOIs
    Publication statusPublished - 2007
    MoE publication typeA4 Article in a conference publication
    Event2006 MRS Fall Meeting: Symposium NN – Scientific Basis for Nuclear Waste Management XXX - Boston, United States
    Duration: 27 Nov 20061 Dec 2006

    Publication series

    SeriesMaterials Research Society Symposia Proceedings
    Volume985
    ISSN0272-9172

    Conference

    Conference2006 MRS Fall Meeting
    CountryUnited States
    CityBoston
    Period27/11/061/12/06

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