방사성폐기물학회지 (Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT))

  • 제22권3호
  • /
  • Pages.287-299
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  • 2024
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  • 1738-1894(pISSN)
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  • 2288-5471(eISSN)
한국방사성폐기물학회 (Korean Radioactive Waste Society)
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Sorption of Tc(IV) in Saline Solutions - II. Sorption on MX-80, Illite, Shale and Limestone in Na-Ca-Cl Solutions

  • 투고 : 2024.04.26
  • 심사 : 2024.06.11
  • 발행 : 2024.09.30
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초록

Technetium has been identified as an element of interest for the safety assessment of a deep geological repository for used nuclear fuel. In this study, the sorption of Tc(IV) onto MX-80 bentonite, illite, and shale in ionic strength (I) 0.1-6 mol·kgw-1 (m) Na-Ca-Cl solutions at pHm = 4-9 and limestone at pHm = 5-9 was studied. Tc(IV) sorption on MX-80 increased with pHm from 4 to 6, reached the maximum at pHm = 6-7, and then gradually decreased with pHm from 7 to 9. Tc(IV) sorption on illite gradually increased with pHm from 4 to 7, and then decreased as pHm increased. The sorption properties of Tc(IV) on shale were quite similar to those on illite. Tc(IV) sorption on limestone slightly increased with pHm from 5 to 6 and then seemed to be constant at pHm = 6-9. Tc(IV) sorption on all four solids was independent of ionic strength (0.1-6 m). The 2 site protolysis non-electrostatic surface complexation and cation exchange model successfully simulated the sorption of Tc(IV) onto MX-80 and illite and the optimized values of surface complexation constants were estimated.

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과제정보

This work was funded by the Nuclear Waste Management Organization of Canada. The authors appreciate Prof. Koichiro Takao at the Tokyo Institute of Technology and Dr. Taishi Kobayashi at Kyoto University for their valuable comments on the experimental methods and the procedures for confirmation of the reduction of Tc(VII) to Tc(IV).

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