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Geochemical, geotechnical and microbiological changes in mg/ca bentonite after thermal loading at 150 °C
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SYSNO ASEP 0545541 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Geochemical, geotechnical and microbiological changes in mg/ca bentonite after thermal loading at 150 °C Author(s) Kašpar, V. (CZ)
Šachlová, Š. (CZ)
Hofmanová, E. (CZ)
Komárková, Bára (UACH-T) RID, SAI, ORCID
Havlová, V. (CZ)
Aparicio, C. (CZ)
Černá, K. (CZ)
Bartak, D. (CZ)
Hlaváčková, V. (CZ)Number of authors 9 Article number 965 Source Title Minerals. - : MDPI
Roč. 11, č. 9 (2021)Number of pages 21 s. Language eng - English Country CH - Switzerland Keywords Cation exchange capacity ; Magnesium bentonite ; Microbial survivability ; Montmorillonite content ; Radioactive waste disposal ; Saturated hydraulic conductivity ; Water retention curves Subject RIV CA - Inorganic Chemistry OECD category Inorganic and nuclear chemistry Method of publishing Open access Institutional support UACH-T - RVO:61388980 UT WOS 000701551800001 EID SCOPUS 85114265210 DOI 10.3390/min11090965 Annotation Bentonite buffers at temperatures beyond 100 °C could reduce the amount of high-level radioactive waste in a deep geological repository. However, it is necessary to demonstrate that the buffer surrounding the canisters withstands such elevated temperatures, while maintaining its safety functions (regarding long-term performance). For this reason, an experiment with thermal loading of bentonite powder at 150 °C was arranged. The paper presents changes that the Czech Mg/Ca bentonite underwent during heating for one year. These changes were examined by X-ray diffraction (XRD), thermal analysis with evolved gas analysis (TA-EGA), aqueous leachates, Cs sorption, cation exchange capacity (CEC), specific surface area (SSA), free swelling, saturated hydraulic conductivity, water retention curves (WRC), quantitative polymerase chain reaction (qPCR), and next-generation sequencing (NGS). It was concluded that montmorillonite was partially altered, in terms of the magnitude of the surface charge density of montmorillonite particles, based on the measurement interpretations of CEC, SSA, and Cs sorption. Montmorillonite alteration towards low-or non-swelling clay structures corresponded well to significantly lower swelling ability and water uptake ability, and higher saturated hydraulic conductivity of thermally loaded samples. Microbial survivability decreased with the thermal loading time, but it was not completely diminished, even in samples heated for one year. Workplace Institute of Inorganic Chemistry Contact Jana Kroneislová, krone@iic.cas.cz, Tel.: 311 236 931 Year of Publishing 2022 Electronic address http://hdl.handle.net/11104/0322227
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