The radiation resistance of natural zeolite, cation exchange resin, carbon sorbent, and titanium phosphate were investigated, as well as the ability to adsorb strontium ions after internal adsorbents irradiation. It is shown, that upon irradiation the adsorption properties of all these materials are slightly reduced. The only exception is titanium phosphate with a surface modified with NH ₄ OH. Initial and residual concentration of stable strontium isotopes was measured by direct complexometric titration. Some experiments were performed with radioactive ⁹⁰ Sr as well. The amount of ⁹⁰ Sr was controlled by liquid scintillation techniques. The values of adsorption of strontium ions by irradiated and non-irradiated samples of amorphous titanium phosphate were determined. The analysis of changes of titanium phosphate surface under the action of external irradiation was conducted by the method of low-temperature nitrogen adsorption-desorption isotherms. The proportion of micro and mesopores, as well as the total surface area of the investigated adsorbent, were estimated. The pore volume and pore radius were calculated by the DFT and BJH methods. A brief comparison of these methods was made.

1. H. Vasylyeva et al.,“Adsorption of zirconium ions by X-type zeolite,” Biointerface Res. Appl. Chem., vol. 11, no. 5, pp. 13421 – 13431, Feb. 2021.
   DOI: 10.33263/BRIAC115.1342113431
2. N. V. Sych et al., “Porous structure and surface chemistry of phosphoric acid activated carbon from corncob,” Appl. Surf. Sci., vol. 261, pp. 75 – 82, Nov. 2012.
   DOI: 10.1016/j.apsusc.2012.07.084
3. Y. Takahatake, A. Shibata, K. Nomura, T. Sato, “Effect of Flowing Water on Sr Sorption. Changes of Hydrous Sodium Titanate,” Minerals, vol. 7, no. 12, 247, Dec. 2017.
   DOI: 10.3390/min7120247
4. I. Mironyuk, T. Tatarchuk, H. Vasylyeva, M. Naushad, I. Mykytyn, “Adsorption of Sr(II) cations onto phosphated mesoporous titanium dioxide: Mechanism, isotherm and kinetics studies,” J. Environ. Chem. Eng., vol. 7, no. 6, 103430, Dec. 2019.
   DOI: 10.1016/j.jece.2019.103430
5. I. F. Mironyuk, I. M. Mykytyn, O. Y. Kaglyan, D. I. Gudkov, H. V. Vasylyeva, “90Sr adsorption from the aquatic environment of Chornobylexclusion zone by chemically enhanced TiO2,” Nucl. Phys. At. Energy, vol. 21, no. 4, pp. 347 – 353, Dec. 2020.
   DOI: 10.15407/jnpae2020.04.347
6. H. Vasylyeva, I. Mironyuk, I. Mykytyn, K. Savka, ^“ Equilibrium studies of yttrium adsorption from aqueous solutions by titanium dioxide,” Appl. Radiat. Isot., vol. 168, 109473, Feb. 2021.
   DOI: 10.1016/j.apradiso.2020.109473
   PMid: 33658128
7. E. A. Abdel-Galil, H. Moloukhia, M. Abdel-Khalik, S. S. Mahrous, “Synthesisand physico-chemical characterization of cellulose/HO₇Sb ₃ nanocomposite as adsorbent for the removal of some radionuclides from aqueous solutions,” Appl. Radiat. Isot., vol. 140, pp. 363 – 373, Oct. 2018.
   DOI: 10.1016/j.apradiso.2018.07.022
   PMid: 30142577
8. I. F. Mironyuk et al., “Effects of enhanced clusterization of water at a surface of partially silylated nanosilica on adsorption of cations and anions from aqueous media,” Microporous Mesoporous Mater., vol. 277, pp. 95 – 104, Mar. 2019.
   DOI: 10.1016/j.micromeso.2018.10.016
9. I. F. Mironyuk, H. V. Vasylyeva, V. I. Mandzyuk, N. A. Bezruka, T. V. Dmytrotsa, “The kinetics of adsorption binding of Ba2+ ions by trimethylsilylated silica,” Phys. Chem. Solid State, vol. 19, no. 1, pp. 66 - 73, Mar. 2018.
   DOI: 10.15330/pcss.19.1.66-73
10. H. V. Vasylyeva et al., “Radiochemical studies of state of lanthanum microamounts in water solution,” J. Mol. Liq., vol. 118, no. 1 - 2, pp. 41 – 44, Apr. 2005.
    DOI: 10.1016/j.molliq.2004.07.008
11. V. V. Strelko, “New sol–gel processes in the synthesis of inorganic sorbents and ion exchangers based on nanoporous oxides and phosphates of polyvalent metals,” J. Solgel Sci. Technol., vol. 68, no. 3, pp. 438 - 446, Mar. 2013.
    DOI: 10.1007/s10971-013-2990-0
12. J. J. Surman, J. M. Pates, H. Zhang, S. Happel, “Development andcharacterization of a new Sr selective resin for the rapid determination of ⁹⁰Sr in environmental water samples,” Talanta, vol. 129, pp. 623 – 628, Nov. 2014.
    DOI: 10.1016/j.talanta.2014.06.041
    PMid: 25127642
13. H. Tazoe, “Novel method for low level Sr-90 activity detection in seawaterby combining oxalate precipitation and chelating resin extraction,” Geochem. J., vol. 51, no. 2, pp. 193 – 197, Mar. 2017.
    DOI: 10.2343/geochemj.2.0441
14. M. M. S. Ali, E. A. Abdel-Galil, M. M. Hamed, “Removal of strontium radionuclides from liquid scintillation waste and environmental water samples,” Appl. Radiat. Isot., vol. 166, 109357, Dec. 2020.
    DOI: 10.1016/j.apradiso.2020.109357
    PMid: 32755756
15. A. Surrao et al., “Improving the separation of strontium and barium with SrResin using chelating eluent solutions,” J. Radioanal. Nucl. Chem., vol. 319, no. 3, pp. 1185 – 1192, Jan. 2019.
    DOI: 10.1007/s10967-019-06432-w
16. V. J. Angadi et al., “Mechanism of γ-irradiation-induced phase transformations in nanocrystalline Mn0.5Zn0.5Fe2O4 ceramics,” J. Solid State Chem., vol. 246, pp. 119 – 124, Feb. 2017.
    DOI: 10.1016/j.jssc.2016.11.017
17. H. M. Khalid, M. T. Rahman, M. K. Basher, M. J. Afzal, M. S. Bashar, “Impact of ionizing radiation doses on nanocrystalline TiO2 layer in DSSC’s photoanode film,” Results Phys., vol. 11, pp. 1172 - 1181, Dec. 2018.
    DOI: 10.1016/j.rinp.2018.10.006
18. I. Mironyuk, I. Mykytyn, H. Vasylyeva, K. Savka, “Sodium-modified mesoporous TiO2: Sol-gel synthesis, characterization and adsorption activity toward heavy metal cations,” J. Mol. Liq., vol. 316, 113840, Oct. 2020.
    DOI: 10.1016/j.molliq.2020.113840
19. Г. Васильєва, В. Яковлев, Ю. Килівник, М. Циба, “Вплив модифікування поверхні фосфату титану на його здатність поглинати йони стронцію із водних розчинів,” Фізика і хімія твердого тіла, т. 17, но. 4, с. 548 – 551, Грудень 2016. (H. Vasylyeva, M. Tsyba, Yu. Kylivnyk, V. Yakovlev, “The Influence of Chemical Modificate of Surface of Titanium Phosphate on its Ability to Sorb Strontium Ions from Aqueous Solutions,” Phys. Chem. Solid State, vol. 17, no. 4, pp. 548 – 551, Dec. 2016.)
    DOI: 10.15330/pcss.17.4.548-551
20. А. Е. Каглян та інші, “Radionuklidy v aborigennykh vidakh ryb Chernobyl`skoj zony otchuzhdeniya,” Ядерна фізика та енергетика, т. 13, но. 3, с. 306 – 315, 2012.(Ye. Kaglyan et al., “Radionuclides in the indigenous fish species of the Chernobyl exclusion zone,” Nucl. Phys. At. Energy, vol. 13, no. 3, pp. 306 – 315, 2012.)
    Retrieved from: http://jnpae.kinr.kiev.ua/13.3/Articles_PDF/jnpae-2012-13-0306-Kaglyan.pdf
    Retrieved on: Dec. 15, 2020
21. Yu. Kilivnik, S. Vuchkan, I. Syika, H. Vasylyeva, O. Sych, “Purification of aqueous solutions from strontium ions by natural and synthetic sorbents under increased radiation background,” in Book of Abstr. 9^th Int. Conf. Radiation and Applications in Various Fields of Research (RAD 2021) , Herceg Novi, Montenegro, 2021, p. 62.
    DOI: 10.21175/rad.abstr.book.2021.11.4
22. S. Agostinelli et al., “Geant4 — a simulation toolkit,” Nucl. Instrum. Methods Phys. Res. A, vol. 506, no. 3, pp. 250 – 303, Jul. 2003.
    DOI: 10.1016/S0168-9002(03)01368-8