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


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
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


Conference2006 MRS Fall Meeting
Country/TerritoryUnited States


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