The Experts below are selected from a list of 579 Experts worldwide ranked by ideXlab platform
V.n. Belyakov - One of the best experts on this subject based on the ideXlab platform.
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Heterogeneous Membranes Modified with Nanoparticles of Inorganic Ion-Exchangers for Whey Demineralization☆
Materials Today: Proceedings, 2020Co-Authors: Yuliya Dzyazko, Yurii Zmievskii, S. L. Vasilyuk, Liudmyla Rozhdestveskaya, Yurii Volfkovich, Valentin E. Sosenkin, N. F. Nikol’skaya, Valerii Myronchuk, V.n. BelyakovAbstract:Composite materials were obtained by modification of polymer ion exchange membranes with nanoparticles of zirconium hydrophosphate and hydrated zirconium dioxide. Empirical parameters related to porosity of the membranes and ion transport were proposed. Nanoparticles (4-20 nm) in clusters and channels of ion exchange polymer improve transport of counter-ions: transport number of cations increases from 0.46 to 0.78 under limiting current. The aggregates in non-transport pores are a barrier against organic matters. The composites were applied to whey electrodialysis. Current efficiency reaches 97% for K+, Na+, Ca2+, Mg2+ cations and 11-22% for HPO42− and H2PO4− anions.
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PHYSICAL CHEMISTRY OF SURFACE PHENOMENA Interaction of Sorbed Ni(II) Ions with Amorphous Zirconium Hydrogen Phosphate
2020Co-Authors: S. Dzyazko, L. M. Rozhdestvenskaya, S. L. Vasilyuk, V. V. Trachevskii, V.n. BelyakovAbstract:Samples of amorphous zirconium hydrogen phosphate with different zirconium and phosphorus concentrations in hydrogen and nickelsubstituted forms are studied by means of electronic, 31 P NMR, and impedance spectroscopy. It is shown that Ni(II) → H + ion exchange is accompanied by the hydrolysis of sorbed cations and the formation of complexes with the dihydroand hydrophosphate groups of the inorganic ionite. It is found that the coordination environment of Ni(II) in the sorbent phase includes 2-4 fragments of phosphate groups, along with OH groups and water molecules.
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Desalination of glycerol-water solutions by electrodyalysis using the organo-inorganic membranes
Journal of Water Chemistry and Technology, 2017Co-Authors: L. M. Rozhdestvenskaya, Yu. S. Dzyazko, E. O. Kudelko, S. L. Vasilyuk, V.n. BelyakovAbstract:The organo–inorganic ion exchange membranes based on heterogeneous membrane materials and inorganic ion exchangers (zirconium hydrophosphate and hydrated zirconium dioxide) have been developed for electrodialysis desalination of glycerol–water solutions. It was shown that the electrodialysis efficiency with pristine polymer membranes decreases with time due to formation of deposit directly in the membrane pores. In contrast, the organo–inorganic membranes exhibit resistance to poisoning by organic substances, and the current yield during the electromembrane treatment can reach 95–98%.
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Composite Ion-Exchangers Based On Flexible Resin Containing Zirconium Hydrophosphate for Electromembrane Separation
2015Co-Authors: Yuliya Dzyazko, Yu. M. Volfkovich, Valentin E. Sosenkin, L.n. Ponomaryova, Vladimir V. Trachevskii, V.n. BelyakovAbstract:Organic-inorganic materials based on flexible gel-like cation exchange resin were obtained by means of its modification with zirconium hydrophosphate. The samples were investigated using transmission and scanning electron microscopy, standard contact porosimetry as well as impedance spectroscopy. Single nanoparticles (4-10 nm) and their aggregates were found inside the polymer. Evolution of porous structure of the polymer constituent affected by the inorganic particles is considered, the modifier has been shown to decrease the content of free water in the polymer, to increase swelling pressure, which is determined according to Gregor model, and to provide a growth of ion-exchange capacity in a comparison with the pristine resin (from 0.56 up to 2.3 mmol cm -3 ). The inorganic constituent formally behaves like a cross-linking agent. However, increasing of the modifier amount causes a growth of electrical conductivity of the composites from 0.2 to 0.8 Ohm -1 m -1 . The ion-exchanger with a maximal content of zirconium phosphate (67 %) was applied to removal of Cd 2+ ions from a solution containing also hardness ions and organics. The composite provide continuity of the process, the removal degree of toxic ions reaches 96-98%. Redistribution of the nanoparticles in the polymer, which is affected by electric field, has been found.
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Polymer Ion-Exchangers Modified with Zirconium Hydrophosphate for Removal of Cd2+ Ions from Diluted Solutions
Separation Science and Technology, 2013Co-Authors: Yuliya Dzyazko, Yurii Volfkovich, Valentin E. Sosenkin, L.n. Ponomaryova, V.n. BelyakovAbstract:Hybrid ion-exchangers have been synthesized by modification of strongly acidic cation-exchange resin with zirconium hydrophosphate. The samples were investigated with scanning and transmission electron microscopy and standard contact porosimetry. Single nanoparticles and their aggregates have been found in the polymer. The nanoparticles in transport pores increase the electrical conductivity of ion-exchanger from 0.21 to 0.65 Ohm−1 m−1. The diffusion coefficient of Cd2+ ions reaches 2.43 × 10−11 m2 s−1 for initial resin and (2.50–4.34) × 10−11 m2 s−1 for nanocomposites. The inorganic constituent improves Cd2+ recovery from a solution, which contains also Ca2+ and Mg2+. The degree of Cd2+ removal is 18% for non-modified resin and 99% for the sample containing 38 mass% zirconium phosphate.
T. V. Safronova - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of the Nanoscale Calcium Hydroxyapatite from Calcium Malate and Ammonium Hydrophosphate
Inorganic Materials: Applied Research, 2019Co-Authors: T. V. Safronova, V. I. Putlyaev, A. V. Knot’ko, T. B. Shatalova, V. Yu. SavinovaAbstract:—A new method for obtaining the nanoscale hydroxyapatite with low crystallinity from aqueous solution of calcium malate Ca(C_4H_5O_5)_2 and ammonium hydrophosphate (NH_4)_2HPO_4 at room temperature, molar ratio Ca/P = 1.67, and pH 9 was proposed. After synthesis and drying, the sample was a transparent composite with a matrix from the by-product of the reaction of organic nature containing nanoscale particles of calcium phosphate. The phase composition of the sample after thermal treatment at 900°C was represented by calcium hydroxyapatite.
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Calcium Phosphate Powder Synthesized from Calcium Acetate and Ammonium Hydrophosphate for Bioceramics Application
Ceramics, 2018Co-Authors: T. V. Safronova, G. K. Kazakova, V.i. Putlayev, Yaroslav Filippov, Tatiana Shatalova, Evgeny A. Karpushkin, Dmitrii Larionov, Yury ShakhtarinAbstract:Calcium phosphate powder was synthesized at room temperature from aqueous solutions of ammonium hydrophosphate and calcium acetate without pH adjusting at constant Ca/P molar ratio 1.5. Phase composition of the as-synthesized powder depended on the precursors concentration: At 2.0 M of calcium acetate in the starting solution, poorly crystallized hydroxyapatite was formed, 0.125 M solution of calcium acetate afforded brushite, and the powders synthesized from 0.25–1.0 M calcium acetate solutions were mixtures of the mentioned phases. Firing at 1100 °C led to complete elimination of the reaction by-products, yet the phase composition of the annealed compacted samples was the following: When 2.0 M solution of calcium acetate was used, the obtained ceramics consisted of β-Ca3(PO4)2, whereas at 0.125 to 1.0 M of calcium acetate, the ceramics was a mixture of β-Ca3(PO4)2 and β-Ca2P2O7. Synthesized calcium phosphate powders can be used as the powdered precursors for biocompatible bioresorbable composite ceramics production.
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Powders Synthesized from Calcium Acetate and Mixed-Anionic Solutions, Containing Orthophosphate and Carbonate Ions, for Obtaining Bioceramic
Glass and Ceramics, 2018Co-Authors: T. V. Safronova, V. I. Putlyaev, A. V. Knot’ko, P. V. Evdokimov, Ya. Yu. Filippov, E. S. Klimashina, K. Kh. Peranidze, S. A. VladimirovaAbstract:X-ray amorphous powder was synthesized from a water solution of calcium acetate and a mixed-anionic HPO 4 2 − / CO 3 2 − $$ \left({\mathrm{HPO}}_4^{2-}/{\mathrm{CO}}_3^{2-}\right) $$ water solution, including ammonium hydrophosphate and ammonium carbonate, at room temperature without pH regulation. The powders synthesized from the mixed-anionic HPO 4 2 − / CO 3 2 − $$ \left({\mathrm{HPO}}_4^{2-}/{\mathrm{CO}}_3^{2-}\right) $$ solution can be recommended for fabricating composite materials with a polymer matrix or for obtaining ceramic containing tricalcium phosphate and calcite phases with firing temperature not exceeding 600°C.
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Synthesis of Calcium-Phosphate Powder from Calcium Formiate and Ammonium Hydrophosphate for Obtaining Biocompatible Resorbable Biphase Ceramic Materials
Glass and Ceramics, 2017Co-Authors: T. V. Safronova, V. I. Putlyaev, Ya. Yu. Filippov, S. A. Vladimirova, D. M. Zuev, G. S. CherkasovaAbstract:Calcium phosphate powder was synthesized from calcium formiate Ca(CHO_2)_2 and ammonium hydrophosphate (NH_4)_2 HPO_4 with Ca/P ratio in the initial water solutions equal to 1. The phase composition of the powders synthesized from 0.5M solutions was represented by brushite CaHPO_4 · 2H_2O and octacalcium phosphate Ca_8(HPO_4)_2 (PO_4)_6 · 6H_2O. After firing at 1100°C the phase composition of the powder was represented by calcium pyrophosphate β-Ca_2P_2O_7 and tricalcium phosphate β-Ca_3 (PO_4)_2. The synthesized powder can be used to obtain biocompatible resorbable biphase ceramic materials and composites with a polymer matrix.
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Ceramics based on calcium phosphate powder synthesized from calcium saccharate and ammonium hydrophosphate
Inorganic Materials: Applied Research, 2016Co-Authors: T. V. Safronova, T. B. Shatalova, G. K. Kazakova, P. V. Yevdokimov, A.v. Knotko, A. V. Korotkova, V. I. PutlyayevAbstract:A microporous ceramic with a pore size ranging from 1 to 6 μm and a relative density up to 56% was obtained from the calcium phosphate powder synthesized from aqueous solutions of monocalcium saccharate (CaC12H22O11) and ammonium hydrophosphate. The composition of the synthesized nanosized powder is found to include hydroxyapatite and sucrose. The phase composition of the ceramic after calcination in the range from 900 to 1200°C is represented by β-tricalcium phosphate and hydroxyapatite. The resulting ceramic material can be recommended for the manufacture of bone implants.
V. I. Putlyaev - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of Calcium Phosphate Powders in Nonaqueous Media for Stereolithography 3D Printing
Russian Journal of Inorganic Chemistry, 2020Co-Authors: D. S. Larionov, P. V. Evdokimov, M. A. Kuzina, A. V. Garshev, N. K. Orlov, V. I. PutlyaevAbstract:Methods were presented to synthesize tricalcium phosphate Ca_3(PO_4)_2 (TCP), calcium pyrophosphate Ca_2P_2O_7 (CPP), and TCP/CPP composites in nonaqueous media in the temperature range 25–300°C. It was shown that solvo- and ionothermal synthesis methods can give phosphates of complex composition. The phase composition, micromorphology, and particle size distribution of the obtained powders and their evolution during synthesis were described. The synthesis at 110°C while slowly adding ammonium hydrophosphate to a solution of calcium ethylene glycolate in ethylene glycol gives a nanocrystalline β-TCP powder with an average size of aggregates of platy crystals of 150 nm and a distribution width of 50 nm. The morphological characteristics and sinterability of the powders synthesized in solutions in ethylene glycol make them suitable for producing macroporous ceramics by stereolithography 3D printing methods.
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Synthesis of the Nanoscale Calcium Hydroxyapatite from Calcium Malate and Ammonium Hydrophosphate
Inorganic Materials: Applied Research, 2019Co-Authors: T. V. Safronova, V. I. Putlyaev, A. V. Knot’ko, T. B. Shatalova, V. Yu. SavinovaAbstract:—A new method for obtaining the nanoscale hydroxyapatite with low crystallinity from aqueous solution of calcium malate Ca(C_4H_5O_5)_2 and ammonium hydrophosphate (NH_4)_2HPO_4 at room temperature, molar ratio Ca/P = 1.67, and pH 9 was proposed. After synthesis and drying, the sample was a transparent composite with a matrix from the by-product of the reaction of organic nature containing nanoscale particles of calcium phosphate. The phase composition of the sample after thermal treatment at 900°C was represented by calcium hydroxyapatite.
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Powders Synthesized from Calcium Acetate and Mixed-Anionic Solutions, Containing Orthophosphate and Carbonate Ions, for Obtaining Bioceramic
Glass and Ceramics, 2018Co-Authors: T. V. Safronova, V. I. Putlyaev, A. V. Knot’ko, P. V. Evdokimov, Ya. Yu. Filippov, E. S. Klimashina, K. Kh. Peranidze, S. A. VladimirovaAbstract:X-ray amorphous powder was synthesized from a water solution of calcium acetate and a mixed-anionic HPO 4 2 − / CO 3 2 − $$ \left({\mathrm{HPO}}_4^{2-}/{\mathrm{CO}}_3^{2-}\right) $$ water solution, including ammonium hydrophosphate and ammonium carbonate, at room temperature without pH regulation. The powders synthesized from the mixed-anionic HPO 4 2 − / CO 3 2 − $$ \left({\mathrm{HPO}}_4^{2-}/{\mathrm{CO}}_3^{2-}\right) $$ solution can be recommended for fabricating composite materials with a polymer matrix or for obtaining ceramic containing tricalcium phosphate and calcite phases with firing temperature not exceeding 600°C.
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Synthesis of Calcium-Phosphate Powder from Calcium Formiate and Ammonium Hydrophosphate for Obtaining Biocompatible Resorbable Biphase Ceramic Materials
Glass and Ceramics, 2017Co-Authors: T. V. Safronova, V. I. Putlyaev, Ya. Yu. Filippov, S. A. Vladimirova, D. M. Zuev, G. S. CherkasovaAbstract:Calcium phosphate powder was synthesized from calcium formiate Ca(CHO_2)_2 and ammonium hydrophosphate (NH_4)_2 HPO_4 with Ca/P ratio in the initial water solutions equal to 1. The phase composition of the powders synthesized from 0.5M solutions was represented by brushite CaHPO_4 · 2H_2O and octacalcium phosphate Ca_8(HPO_4)_2 (PO_4)_6 · 6H_2O. After firing at 1100°C the phase composition of the powder was represented by calcium pyrophosphate β-Ca_2P_2O_7 and tricalcium phosphate β-Ca_3 (PO_4)_2. The synthesized powder can be used to obtain biocompatible resorbable biphase ceramic materials and composites with a polymer matrix.
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Calcium Phosphate Ceramic Based on Powder Synthesized From a Mixed-Anionic Solution
Glass and Ceramics, 2016Co-Authors: T. V. Safronova, V. I. Putlyaev, A. V. Knot’ko, T. B. Shatalova, P. V. Evdokimov, M. S. KostinAbstract:Ceramic based on calcium phosphates is obtained from powders synthesized from water solutions of calcium nitrate, ammonium hydrophosphate, and ammonium pyrophosphate as well as from a mixed-anionic solution containing simultaneously ammonium pyro- and orthophosphate in the molar ratio (NH_4)_2HPO_4/(NH_4)_4P_2O_7 = 1. The ceramic obtained contains biocompatible bioresorbable phases and can be used to make implants used in regenerative methods for the treatment of bone tissue defects. This represents the first time synthesis from mixed-anionic solutions is used to obtain powders of calcium phosphates with significant quantities of each anion.
V. T. Kalinnikov - One of the best experts on this subject based on the ideXlab platform.
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Compositional dependence of the ion-exchange properties of a sorbent based on oxotitanium hydrophosphate
Russian Journal of Applied Chemistry, 2008Co-Authors: V. I. Ivanenko, E. P. Lokshin, R. I. Korneikov, S. V. Aksenova, V. T. KalinnikovAbstract:Effect of the degree of hydration and the phosphorus to titanium ratio in sorbents based on hydrated oxotitanium hydrophosphate on their sorption properties: constant of heterogeneous substitution of hydrogen ions by cations of sodium, cesium, and strontium and static exchange capacity, was studied.
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Synthesis of fine powders of KTP-group compounds of stoichiometric composition
Powder Technology, 2006Co-Authors: V. I. Ivanenko, E. P. Lokshin, I. A. Udalova, Michael Rosenbluh, Yu. Kaganovskii, S.v. Zdobina, V. T. KalinnikovAbstract:Precipitation of crystalline monophase nanopowders (50–100 nm in diameter) of stoichiometric binary orthophosphates of titanyl and alkaline metal in aqueous solutions has been studied. It has been shown that, in the formation of those powders, titanyl hydrophosphate can be used as a precursor. Rising temperature and alkaline ion concentration in the solution decrease the size of the powder grains, while elongating the exposure of the synthesized solid phase in the suspension increases grain sizes. An effective technique to synthesize fine-dispersed powders of monophase stoichiometric binary orthophosphates of titanyl and alkaline metal has been developed.
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Purification of Water–Salt Solutions by Ti(IV) and Zr(IV) Phosphates
Atomic Energy, 2002Co-Authors: E. P. Lokshin, V. I. Ivanenko, Kh.-m. B. Avsaragov, V. V. Vladimirova, V. T. KalinnikovAbstract:The sorption of γ- and β-emitting radionuclides from processed solutions of liquid wastes with a salt background, using powdered titanium and zirconium phosphates with the composition TiO(OH)_2(1– x )(HPO_4)_ x · n H_2O, where x = 0.23–1, and Zr(HPO_4)_2· n H_2O, was studied. The decontamination process was most efficient on titanyl hydrophosphate in the range pH = 4–6. It was found that stagewise sorption of radionuclides under static conditions and with flow of solution and sorbent is best. It was found that for decontamination of liquid wastes an amorphous sorbent based on titanium (IV) hydroxide-phosphate matrix makes it possible to remove radionuclides and simultaneously petroleum products from the processed solutions.
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Purification of water-salt solutions by Ti(IV) and Zr(IV) phosphates
Atomic Energy, 2002Co-Authors: E. P. Lokshin, V. I. Ivanenko, Kh.-m. B. Avsaragov, V. V. Vladimirova, V. T. KalinnikovAbstract:The sorption of γ- and β-emitting radionuclides from processed solutions of liquid wastes with a salt background, using powdered titanium and zirconium phosphates with the composition TiO(OH)2(1–x)(HPO4) x ·nH2O, where x = 0.23–1, and Zr(HPO4)2·nH2O, was studied. The decontamination process was most efficient on titanyl hydrophosphate in the range pH = 4–6. It was found that stagewise sorption of radionuclides under static conditions and with flow of solution and sorbent is best. It was found that for decontamination of liquid wastes an amorphous sorbent based on titanium (IV) hydroxide-phosphate matrix makes it possible to remove radionuclides and simultaneously petroleum products from the processed solutions.
E. P. Lokshin - One of the best experts on this subject based on the ideXlab platform.
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Sorption extraction of lanthanides from phosphoric acid solutions
Russian Journal of Applied Chemistry, 2009Co-Authors: E. P. Lokshin, V. I. Ivanenko, O. A. Tareeva, R. I. KorneikovAbstract:The possibility of sorption extraction of lanthanides from nitric-phosphoric and phosphoric acid solutions with inorganic sorbents based on hydrated titanyl hydrophosphate was studied. New technological solutions were suggested for lanthanide sorption from the products which are formed in processing of the Khibiny apatite concentrate on mineral fertilizers (frozen nitric-phosphoric acid extract, a product of nitric acid decomposition of apatite, and the production phosphoric acid from the dihydrate process).
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Compositional dependence of the ion-exchange properties of a sorbent based on oxotitanium hydrophosphate
Russian Journal of Applied Chemistry, 2008Co-Authors: V. I. Ivanenko, E. P. Lokshin, R. I. Korneikov, S. V. Aksenova, V. T. KalinnikovAbstract:Effect of the degree of hydration and the phosphorus to titanium ratio in sorbents based on hydrated oxotitanium hydrophosphate on their sorption properties: constant of heterogeneous substitution of hydrogen ions by cations of sodium, cesium, and strontium and static exchange capacity, was studied.
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Synthesis of fine powders of KTP-group compounds of stoichiometric composition
Powder Technology, 2006Co-Authors: V. I. Ivanenko, E. P. Lokshin, I. A. Udalova, Michael Rosenbluh, Yu. Kaganovskii, S.v. Zdobina, V. T. KalinnikovAbstract:Precipitation of crystalline monophase nanopowders (50–100 nm in diameter) of stoichiometric binary orthophosphates of titanyl and alkaline metal in aqueous solutions has been studied. It has been shown that, in the formation of those powders, titanyl hydrophosphate can be used as a precursor. Rising temperature and alkaline ion concentration in the solution decrease the size of the powder grains, while elongating the exposure of the synthesized solid phase in the suspension increases grain sizes. An effective technique to synthesize fine-dispersed powders of monophase stoichiometric binary orthophosphates of titanyl and alkaline metal has been developed.
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Purification of Water–Salt Solutions by Ti(IV) and Zr(IV) Phosphates
Atomic Energy, 2002Co-Authors: E. P. Lokshin, V. I. Ivanenko, Kh.-m. B. Avsaragov, V. V. Vladimirova, V. T. KalinnikovAbstract:The sorption of γ- and β-emitting radionuclides from processed solutions of liquid wastes with a salt background, using powdered titanium and zirconium phosphates with the composition TiO(OH)_2(1– x )(HPO_4)_ x · n H_2O, where x = 0.23–1, and Zr(HPO_4)_2· n H_2O, was studied. The decontamination process was most efficient on titanyl hydrophosphate in the range pH = 4–6. It was found that stagewise sorption of radionuclides under static conditions and with flow of solution and sorbent is best. It was found that for decontamination of liquid wastes an amorphous sorbent based on titanium (IV) hydroxide-phosphate matrix makes it possible to remove radionuclides and simultaneously petroleum products from the processed solutions.
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Purification of water-salt solutions by Ti(IV) and Zr(IV) phosphates
Atomic Energy, 2002Co-Authors: E. P. Lokshin, V. I. Ivanenko, Kh.-m. B. Avsaragov, V. V. Vladimirova, V. T. KalinnikovAbstract:The sorption of γ- and β-emitting radionuclides from processed solutions of liquid wastes with a salt background, using powdered titanium and zirconium phosphates with the composition TiO(OH)2(1–x)(HPO4) x ·nH2O, where x = 0.23–1, and Zr(HPO4)2·nH2O, was studied. The decontamination process was most efficient on titanyl hydrophosphate in the range pH = 4–6. It was found that stagewise sorption of radionuclides under static conditions and with flow of solution and sorbent is best. It was found that for decontamination of liquid wastes an amorphous sorbent based on titanium (IV) hydroxide-phosphate matrix makes it possible to remove radionuclides and simultaneously petroleum products from the processed solutions.
