CO2 effect on the pH of compacted bentonite buffer on the laboratory scale

Aku Itälä (Corresponding Author), Joonas Järvinen, A. Muurinen

    Research output: Contribution to journalArticleScientificpeer-review

    2 Citations (Scopus)

    Abstract

    Disposal of Finnish spent nuclear fuel is planned to be based on the KBS-3 repository concept. The role of the bentonite buffer in this concept is essential, and thus the behaviour of the bentonite has to be known. The experiments in this paper concentrated on providing information about the effects of carbon dioxide CO2(g) partial pressure on compacted sodium bentonite, giving an insight into the buffering capacity. The experimental setup consisted of a hermetic box which had a CO2-adjusted atmosphere, and the bentonite was in contact with this atmosphere through water reservoirs. The results indicated that it is possible to measure online the changing pH in the porewater inside compacted bentonite using IrOx electrodes. It was found that the pH fell if the CO2 partial pressure increased above atmospheric conditions. The experimental results indicated a greater fall in pH than in our model in the test cases where CO2 was present. The pH in the experiment with 0 PCO2 remained nearly constant throughout the 5 month period. On the other hand, the pH dropped to near 6 with 0.3 PCO2 and to 5.5 with 1 PCO2 .
    Original languageEnglish
    Pages (from-to)277-283
    Number of pages6
    JournalClay Minerals
    Volume48
    Issue number2
    DOIs
    Publication statusPublished - 2013
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Bentonite
    bentonite
    Buffers
    partial pressure
    Partial pressure
    atmosphere
    Spent fuels
    Nuclear fuels
    buffering
    Carbon Dioxide
    repository
    porewater
    electrode
    carbon dioxide
    experiment
    Sodium
    Experiments
    sodium
    laboratory
    effect

    Keywords

    • alteration
    • bentonite
    • buffer
    • carbon dioxide
    • compaction
    • ph

    Cite this

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    title = "CO2 effect on the pH of compacted bentonite buffer on the laboratory scale",
    abstract = "Disposal of Finnish spent nuclear fuel is planned to be based on the KBS-3 repository concept. The role of the bentonite buffer in this concept is essential, and thus the behaviour of the bentonite has to be known. The experiments in this paper concentrated on providing information about the effects of carbon dioxide CO2(g) partial pressure on compacted sodium bentonite, giving an insight into the buffering capacity. The experimental setup consisted of a hermetic box which had a CO2-adjusted atmosphere, and the bentonite was in contact with this atmosphere through water reservoirs. The results indicated that it is possible to measure online the changing pH in the porewater inside compacted bentonite using IrOx electrodes. It was found that the pH fell if the CO2 partial pressure increased above atmospheric conditions. The experimental results indicated a greater fall in pH than in our model in the test cases where CO2 was present. The pH in the experiment with 0 PCO2 remained nearly constant throughout the 5 month period. On the other hand, the pH dropped to near 6 with 0.3 PCO2 and to 5.5 with 1 PCO2 .",
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    author = "Aku It{\"a}l{\"a} and Joonas J{\"a}rvinen and A. Muurinen",
    year = "2013",
    doi = "10.1180/claymin.2013.048.2.09",
    language = "English",
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    CO2 effect on the pH of compacted bentonite buffer on the laboratory scale. / Itälä, Aku (Corresponding Author); Järvinen, Joonas; Muurinen, A.

    In: Clay Minerals, Vol. 48, No. 2, 2013, p. 277-283.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - CO2 effect on the pH of compacted bentonite buffer on the laboratory scale

    AU - Itälä, Aku

    AU - Järvinen, Joonas

    AU - Muurinen, A.

    PY - 2013

    Y1 - 2013

    N2 - Disposal of Finnish spent nuclear fuel is planned to be based on the KBS-3 repository concept. The role of the bentonite buffer in this concept is essential, and thus the behaviour of the bentonite has to be known. The experiments in this paper concentrated on providing information about the effects of carbon dioxide CO2(g) partial pressure on compacted sodium bentonite, giving an insight into the buffering capacity. The experimental setup consisted of a hermetic box which had a CO2-adjusted atmosphere, and the bentonite was in contact with this atmosphere through water reservoirs. The results indicated that it is possible to measure online the changing pH in the porewater inside compacted bentonite using IrOx electrodes. It was found that the pH fell if the CO2 partial pressure increased above atmospheric conditions. The experimental results indicated a greater fall in pH than in our model in the test cases where CO2 was present. The pH in the experiment with 0 PCO2 remained nearly constant throughout the 5 month period. On the other hand, the pH dropped to near 6 with 0.3 PCO2 and to 5.5 with 1 PCO2 .

    AB - Disposal of Finnish spent nuclear fuel is planned to be based on the KBS-3 repository concept. The role of the bentonite buffer in this concept is essential, and thus the behaviour of the bentonite has to be known. The experiments in this paper concentrated on providing information about the effects of carbon dioxide CO2(g) partial pressure on compacted sodium bentonite, giving an insight into the buffering capacity. The experimental setup consisted of a hermetic box which had a CO2-adjusted atmosphere, and the bentonite was in contact with this atmosphere through water reservoirs. The results indicated that it is possible to measure online the changing pH in the porewater inside compacted bentonite using IrOx electrodes. It was found that the pH fell if the CO2 partial pressure increased above atmospheric conditions. The experimental results indicated a greater fall in pH than in our model in the test cases where CO2 was present. The pH in the experiment with 0 PCO2 remained nearly constant throughout the 5 month period. On the other hand, the pH dropped to near 6 with 0.3 PCO2 and to 5.5 with 1 PCO2 .

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    KW - bentonite

    KW - buffer

    KW - carbon dioxide

    KW - compaction

    KW - ph

    U2 - 10.1180/claymin.2013.048.2.09

    DO - 10.1180/claymin.2013.048.2.09

    M3 - Article

    VL - 48

    SP - 277

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    JO - Clay Minerals

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    SN - 0009-8558

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