Interplay between storage temperature, medium and leaching kinetics of hazardous wastes in Metakaolin-based geopolymer.
J Hazard Mater
; 384: 121377, 2020 02 15.
Article
em En
| MEDLINE
| ID: mdl-31629598
Notwithstanding the success of carbon-free nuclear power in the new energy industry, an effective way to address nuclear contamination is still lacking. As a generally accepted method to date, immobilization of radioactive nuclear wastes with inexpensive and environment-friendly matrix such as geopolymer has attracted extensive attention. In this contribution, Na-based and K-based metakaolin geopolymer were prepared to encapsulate simulated radioactive Cs+ and Sr2+ under different temperatures and environments during long-term leaching tests. The temperature-dependent and environmental-dependent leaching kinetics as well as their dominant leaching mechanisms have been revealed. The results showed that Na-based and K-based geopolymer exhibited better immobilization performance than that of Portland cement, ceteris paribus. For the immobilization of Cs+, Na-based geopolymer showed lower leaching rate than K-based geopolymer under the same leaching conditions. Both higher temperature and salt solution accelerated the leaching behaviors of Sr+ and Cs2+ from the encapsulation matrix. This contribution sheds light on understanding the dominant leaching mechanisms of hazardous elements under different storage environments and highlights the significance of salt-tolerant matrix for the immobilization of nuclear wastes.
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MEDLINE
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En
Ano de publicação:
2020
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Article