The sorption performance of corroded Gaomiaozi bentonite by evolved cement water at different temperatures: the case of europium removal

In the Chinese high-level radioactive waste geological disposal program, Gaomiaozi (GMZ) bentonite has been selected as the potential buffer/backfill material. After the closure of the repository, the Ca-OH-type alkaline solution (evolved cement water) released by cement degradation may last for mor...

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Bibliographic Details
Published in:Environmental science and pollution research international 2020-07, Vol.27 (20), p.25057-25068
Main Authors: Sun, Zhao, Chen, Yong-gui, Shang, Yinghui, Cui, Yu-jun, Ye, Wei-min, Wu, Dong-bei
Format: Article
Language:English
Subjects:
Aquatic Pollution
Atmospheric Protection/Air Quality Control/Air Pollution
Backfill
Bentonite
Cement
Corrosion
Dry density
Earth and Environmental Science
Ecotoxicology
Engineering Sciences
Environment
Environmental Chemistry
Environmental Health
Environmental science
Europium
High level radioactive wastes
High temperature
Mechanics
Mechanics of materials
Radioactive waste disposal
Radioactive wastes
Repositories
Research Article
Sorption
Waste Water Technology
Water Management
Water Pollution Control
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Summary:In the Chinese high-level radioactive waste geological disposal program, Gaomiaozi (GMZ) bentonite has been selected as the potential buffer/backfill material. After the closure of the repository, the Ca-OH-type alkaline solution (evolved cement water) released by cement degradation may last for more than 100,000 years. The bentonite will undergo the corrosion of evolved cement water (ECW) for a long period. This work focuses on the sorption property of GMZ bentonite altered by ECW. Firstly, the corrosion experiments on compacted GMZ specimens with the dry density of 1.70 Mg/m 3 were carried out under constant volume conditions at two temperatures. Then, the sorption of europium (Eu (III)) onto the corroded GMZ bentonite was studied by batch experiments. The results of batch sorption tests indicate that the altered GMZ bentonite keeps an effective removal property with the uptake of Eu (III) more than 99%. The effect of high-temperature conditions of the repository on the sorption property of bentonite is not significant. The results also suggest that the evolved cement water presents no detrimental effect on the long-term adsorption performance of bentonite even under higher temperature conditions.
ISSN:0944-1344
1614-7499
DOI:10.1007/s11356-020-08895-x