Adsorption behavior of Se(Ⅳ) and Se(Ⅵ) on sodium bentonite
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Cong Huang
and
Rong Hua
Abstract
Se is one of the radionuclides focused on in the safety evaluation of deep geological disposal repositories for high-level wastes, and elements with different valence states have different chemical properties and adsorption behaviors, which directly affects their adsorption efficiency and mechanism on bentonite. This study investigated the adsorption behavior of selenium in different valence states (Se(IV) and Se(VI)) on sodium bentonite through batch static adsorption experiments to assess its potential application in deep geological disposal repositories. The results indicate that the adsorption distribution coefficients (Kd) of Se(IV) and Se(VI) on sodium-based bentonite decrease first, then increase, and finally decrease again with increasing pH. However, the adsorption of Se(IV) is less affected by ionic strength, while the adsorption of Se(VI) decreases with increasing ionic strength, temperature, and initial concentration. The adsorption of Se(IV) is an entropy-increasing, non-spontaneous, and endothermic chemical process influenced by environmental pH, which can be described by the Langmuir isotherm model and the pseudo-second-order kinetic model; the adsorption of Se(VI) is a pH-dependent, entropy-decreasing, spontaneous, and exothermic physical process, which can be described by the Langmuir isotherm model and the pseudo-first-order kinetic model. Both exhibit weak competitive adsorption on sodium-based bentonite, and the electrostatic repulsive forces between the negatively charged Se species and the sodium-based bentonite surface inhibit adsorption. FTIR and XRD spectral analyses show no significant changes in functional group characteristics before and after adsorption. The research results are of great significance for understanding the behavior of nuclides during geological migration.
Funding source: Project of Nuclear Technology Research and Development (Proto-Nuclear Energy Development)
Award Identifier / Grant number: HNKF202311(48)
Funding source: The China Uranium Industry Co., Ltd.- the Foundation of State Key Laboratory of Nuclear Resources and Environment Joint Innovation Fund Project
Award Identifier / Grant number: 2022NRE-LH-15
Funding source: Key Project of Jiangxi Natural Science Foundation
Award Identifier / Grant number: 20232ACB203014
Acknowledgments
The China Uranium Industry Co., Ltd.- the Foundation of State Key Laboratory of Nuclear Resources and Environment Joint Innovation Fund Project (2022NRE-LH-15), Key Project of Jiangxi Natural Science Foundation (20232ACB203014) and Project of Nuclear Technology Research and Development (Proto-Nuclear Energy Development) (HNKF202311(48)).
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Research ethics: The local Institutional Review Board deemed the study exempt from review. OR.
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Informed consent: Informed consent was obtained from all individuals included in this study, or their legal guardians or wards.
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Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Use of Large Language Models, AI and Machine Learning Tools: None declared.
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Conflict of interest: All other authors state no conflict of interest.
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Research funding: The China Uranium Industry Co., Ltd.- the Foundation of State Key Laboratory of Nuclear Resources and Environment Joint Innovation Fund Project (2022NRE-LH-15), Key Project of Jiangxi Natural Science Foundation (20232ACB203014) and Project of Nuclear Technology Research and Development (Proto-Nuclear Energy Development) (HNKF202311(48)).
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Data availability: The data in this article can be made public without any restrictions.
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© 2025 Walter de Gruyter GmbH, Berlin/Boston
Articles in the same Issue
- Frontmatter
- Serpent 2 simulations of the historic Haigerloch B8 nuclear reactor of 1945
- Safety behaviour of a material testing reactor using U3Si2 fuel during reactivity insertion accident
- Augmentation of the neutronic safety aspect of high-density fuel research reactor using new control element design
- Analysis of neutronic performance of VVER 1200 reactor using accident tolerant fuel
- Reliability assessment of equal height difference passive containment cooling system based on the adaptive metamodel-based subset importance sampling method in inverse uncertainty quantification framework
- Numerical investigation of three-tube intertwined HX design
- Prediction of LOCA break sizes using LSTM architecture for pressurized water reactors
- Decoupling and controller design of multivariable systems for small modular reactors
- Adsorption behavior of Se(Ⅳ) and Se(Ⅵ) on sodium bentonite
- Calendar of events
Articles in the same Issue
- Frontmatter
- Serpent 2 simulations of the historic Haigerloch B8 nuclear reactor of 1945
- Safety behaviour of a material testing reactor using U3Si2 fuel during reactivity insertion accident
- Augmentation of the neutronic safety aspect of high-density fuel research reactor using new control element design
- Analysis of neutronic performance of VVER 1200 reactor using accident tolerant fuel
- Reliability assessment of equal height difference passive containment cooling system based on the adaptive metamodel-based subset importance sampling method in inverse uncertainty quantification framework
- Numerical investigation of three-tube intertwined HX design
- Prediction of LOCA break sizes using LSTM architecture for pressurized water reactors
- Decoupling and controller design of multivariable systems for small modular reactors
- Adsorption behavior of Se(Ⅳ) and Se(Ⅵ) on sodium bentonite
- Calendar of events
