Sorbents for radioactive waste and heavy metals

Contact persons: Jan Šubrt, Monika Motlochová
Titanic acid has a general formula of [TiOx(OH)4-2x]n. Various simple titanic acids have been described previously. However, due to the predominantly amorphous nature of this material, there is currently no crystallographic characterization, and only limited spectroscopic characterization is available. Metatitanic acid (H2TiO3) is an important intermediate in the production of titanium dioxide via the sulfate process. The high sorption capacity of this material for various cations and anions is well known, but some of its properties, such as poor filterability and the formation of stable colloids in aqueous environments, limit its broader use. A new method has been developed to prepare micro-rods of metatitanic acid derivatives in an aqueous environment, starting from solid titanyl sulfate hydrate crystals with a defined morphology. The particle size and morphology of the starting hydrated titanyl sulfate are well preserved in the pseudomorphs of the amorphous metatitanic acid, including details such as the layered structure of the original hydrated titanyl sulfate crystals. This material eliminates all the disadvantages of metatitanic acid for practical use as a sorbent while maintaining its high sorption capacity. The material exhibits a high sorption capacity for both radioactive ions (Cs+, Sr2+, Co2+, Eu3+, UO22+) and heavy metals (Pb2+, Cd2+, etc.), as well as for some organic cations (amines).

Contact person: Petra Ecorchard
Another group of sorbents that have been studied for a longer time, specifically for the sorption and detection of the aforementioned heavy metals and radionuclides, are generally nanocomposites with graphene oxide. Depending on the specific application, these nanocomposites contain either a polymer matrix or zeolite and sometimes even exfoliated graphite. Zeolites are studied to determine their limits, potential applications in radionuclide sorption, and possibly their selectivity. The nanocomposites are sometimes modified with ionic liquids, predominantly of the imidazolium type. This type of ionic liquid is widely used and contributes to the broader application of nanocomposite sorbents, which, depending on their composition, can also be applied to detect selected radionuclides.

References

1. M. Motlochová, L. Szatmáry, E. Plizingrová, P. Salacova, R. Fajgar, S. Lidin and J. Subrt, Highly efficient eco-friendly sodium titanate sorbents of Cs(I), Sr(II), Co(II) and Eu(III): synthesis, characterization and detailed adsorption study, Rsc Advances, 14(1) (2024) 743-754.
2. Fialova, K., et al. (2021). "Removal of manganese by adsorption onto newly synthesized TiO2-based adsorbent during drinking water treatment." Environmental Technology: 1-38.
3. M. Motlochova, V. Slovak, E. Plizingrova, S. Lidin, J. Subrt, Highly-efficient removal of Pb(ii), Cu(ii) and Cd(ii) from water by novel lithium, sodium and potassium titanate reusable microrods, RSC Advances, 10 (2020) 3694-3704.
4. M. Motlochova, V. Slovák, E. Pližingrová, L. Szatmáry, P. Bezdička, J. Šubrt, The influence of annealing temperature on properties of TiO based materials as adsorbents of radionuclides, Thermochimica Acta, (2019).
5. M. Motlochova, V. Slovak, E. Plizingrova, M. Klementova, P. Bezdicka, J. Subrt, Thermal decomposition study of nanostructured amorphous lithium, sodium and potassium metatitanates, Thermochimica Acta, 670 (2018) 148-154.
6. M. Klementova, M. Motlochova, J. Bohacek, J. Kupcik, L. Palatinus, E. Plizingrova, L. Szatmary, J. Subrt, Metatitanic Acid Pseudomorphs after Titanyl Sulfates: Nanostructured Sorbents and Precursors for Crystalline Titania with Desired Particle Size and Shape, Crystal Growth & Design, 17 (2017) 6762-6769.
7. M. Bubenikova, P. Ecorchard, L. Szatmary, O. Mrozek, P. Salacova, J. Tolasz, Sorption of Sr(II) onto nanocomposites of graphene oxide-polymeric matrix, Journal of Radioanalytical and Nuclear Chemistry, 315 (2018) 263-272.
8. J. Ederer, P. Ecorchard, M. Šrámová Slušná, J. Tolasz, D. Smržová, S. Lupínková, P. Janoš, A Study of Methylene Blue Dye Interaction and Adsorption by Monolayer Graphene Oxide, Adsorption Science & Technology, (2022) 7385541.
9. D. Smrzova, L. Szatmary, P. Ecorchard, A. Machalkova, M. Marikova, P. Salacova, M. Straka, Carbon and zeolite-based composites for radionuclide and heavy metal sorption, Heliyon, 8(12) (2022) e12293.
10. D. Smržová, P. Mohan Ramteke, P. Ecorchard, J. Šubrt, P. Bezdička, D. Kubániová, M. Kormunda, R. Maršálek, X. Vislocká, A. Vykydalová, S. Kumar Singh, R. Wathore, V. M. Shinde, N. K. Labhasetwar, Simultaneous removal of selenium and microbial contamination from drinking water using modified ferrihydrite-based adsorbent, J. Water Process Eng., 56 (2023) 104337.

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