Bentonite Rock from Oglanlynski Field (Turkmenistan) and Composites Based on It as Sorbents for 90 Sr
- PDF / 482,978 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 13 Downloads / 209 Views
ICAL CHEMISTRY OF WATER TREATMENT PROCESSES
Bentonite Rock from Oglanlynski Field (Turkmenistan) and Composites Based on It as Sorbents for 90Sr S. A. Kobetsa, *, A. A. Kosorukova, V. Ya. Demchenkoa, and G. N. Pshinkoa a
A.V. Dumansky Institute of Colloid Chemistry and Water Chemistry, National Academy of Sciences, Kyiv, Ukraine *e-mail: [email protected] Received May 7, 2020; revised May 12, 2020; accepted May 14, 2020
Abstract—Removal of 90Sr from aqueous media by sorbents prepared from bentonite from the Oglanlynski field and by their composites with magnetite is studied. It is shown that the sorbents can be used for purification of large volumes of radioactively contaminated waters. Here, we study bentonite rock material (a natural mineral), montmorillonite in Na-form derived from it, clinoptilolite and cristobalite (impurities in bentonite), and composites obtained by depositing magnetite onto the surface of listed materials. The 90Sr sorption is effective in a broad pH range (3.7–9). The developed composites can be successfully used in purification of radioactively contaminated aquatic environments. The magnetite in sorbents functions exclusively as a magnetically active component, which enables us to use an external magnetic field in separation of sludge resulting from water purification process. The maximum adsorption of strontium ions, as calculated from the Langmuir equation, is obtained for montmorillonite in Na-form and the initial rock material: 20.8 and 14.5 mg/g, respectively. For the composites based on these materials, the values are smaller: 18.5 and 10.6 mg/g, respectively. The effectiveness of sorbents for removal of 90Sr from natural waters and liquid radioactive wastes is shown to be determined mostly by the mineral content of media to be purified, i.e., the type and concentration of macro elements: Na+, K+, and Ca2+. Among the indicated competing ions, calcium affects the removal of strontium from aquatic environments to the largest extent. Keywords: strontium-90, water purification, sorption, bentonite, montmorillonite, composites, magnetite DOI: 10.3103/S1063455X20040050
INTRODUCTION The Fukushima nuclear accident that occurred in Japan in 2011 showed that in nuclear power plants large-scale accidents similar to the Chernobyl disaster are not accidental. Ukraine is surrounded by more than 160 operating nuclear units of nuclear power plants located in different countries of the Western and Eastern Europe (worldwide there are overall 192 nuclear plants with 438 nuclear units). Although a chance for an accident to occur in these plants is reduced to a minimum, such a possibility cannot be fully eliminated. In modern radioecology, removal of radionuclides with a high migration ability, such as U(VI), Np(V), and Tc(VII), from contaminated natural and waste waters is a very important problem for countries with developed nuclear energy industry. High-charge cations of americium, plutonium, and other transuranium elements can rapidly bind to mineral and organo-mineral constituents of soils and to aqu
Data Loading...
