The results of a study of the influence of the thickness of porous glass (PG) plates modified with zinc oxide on its photocatalytic properties and ability to photogenerate oxygen in aqueous media are presented.

Composite materials (CMs) based on matrices of high-silica porous glasses activated by Cu2+ and Y3+ ions are synthesized. The influence of the composition of composites (concentration and ratio of copper and yttrium introduced) and the temperature of their heat treatment (in the range of 50–870°C) on their spectral properties is studied. Examining samples using optical and IR spectroscopy reveals absorption bands related to Cu2+ ions and caused by vibrations of the Y–O bonds in Y2O3. It is established that, depending on the synthesis conditions, the obtained materials possess UV, blue-green, and IR luminescence due to the presence of various active centers (defects and oxygen vacancies in CuO, Cu2+ ions, radicals , and F centers in Y2O3, =Si0 centers, E' centers (O3≡ Si· ), neutral oxygen vacancies (O3≡Si–Si≡O3), and nonbridging oxygen defect centers in the silica matrix of glass.

Bismuth-containing composite materials (CMs) with variable yttrium oxide content are synthesized by impregnating porous silicate glass matrices in acidified aqueous-salt solutions of Bi(NO3)3·5H2O in the presence of Y(NO3)3·6H2O with their subsequent heat treatment at 650 or 870°C, and their luminescent properties are studied. It is found that the synthesized materials exhibit photoluminescence in a wide spectral range (230–900 nm) due to the presence of various active centers (=Si0, Y3+– O_3^2 - , Si-BAC (silicon-associated bismuth active centers), radicals , Bi3+ and Bi2+ ions, Bi3+ pairs, silicon–oxygen defects), as well as the Bi3+ → Y3+ MMCT (metal-to-metal charge transfer) transition, as a result of which they can be considered as new promising solid-state phosphors.

This paper presents the results of a study of the toxicity of high-silica quartzoid glasses (QGs) containing cesium, obtained on the basis of two-phase alkali borosilicate glass. It is established that the toxicity of the studied QGs in relation to Paramecium caudatum does not exceed the permissible level and varies depending on the content of alkaline ions in the QG and the time of contact of fine QG powder with water. It is assumed that the identified toxicity is associated primarily with the extraction of sodium and cesium ions into the aqueous solution.

Исследовано взаимодействие водного раствора нитрата стронция с допированными магнием калий-титанатными нанотрубками, синтезированными методом соосаждения с последующей гидротермальной обработкой. Установлено, что после 2 ч выдержки в растворе при комнатной температуре наибольшую сорбционную емкость проявил состав с замещением 10 ат.% титана магнием. Полученные результаты показывают перспективность использования допированных магнием калий-титанатных нанотрубок в качестве адсорбентов ионов стронция из водных растворов.

The interaction of an aqueous solution of strontium nitrate with magnesium-doped potassium titanate nanotubes synthesized by coprecipitation followed by hydrothermal treatment is studied. It is found that after 2 h of exposure in the solution at room temperature, the composition with the replacement of 10 at % titanium by magnesium showed the greatest sorption capacity. The results obtained show the promise of using magnesium-doped potassium titanate nanotubes as adsorbents of strontium ions from aqueous solutions.

New vitreous composite materials (CMs) with two magnetic subsystems are synthesized by impregnation magnetite-containing matrices from iron-containing nanoporous glasses in aqueous MnCl 2 and H 2 C 2 O 4 solutions and the subsequent formation of manganese oxides Mn x O y ( x = 1, 2, 3; y = 1, 2, 3, 4) inside the pore space of the matrices as a result of thermolysis of the reaction product of the dopants (MnC 2 O 4 ). The chemical (elemental) and phase compositions, the valence-coordination state of iron and manganese, and the characteristics of the magnetic state of the synthesized CMs are studied and compared with the characteristics of nanoporous matrices.

The adsorption of lithium, sodium, and potassium cations by synthetic aluminosilicate sorbents of various chemical compositions and particle morphologies is studied. Layered silicates with the montmorillonite structure, framework aluminosilicates, and layered silicates of the kaolinite subgroup with spherical and platy particle morphology are used as objects of the study. The adsorption of sodium and potassium cations is studied from synthetic biological fluids simulating blood plasma, and the adsorption of lithium cations is studied from aqueous solutions of lithium carbonate. The concentration of cations in solutions and samples is determined by flame photometry. The results obtained showed the promise of using synthetic aluminosilicate sorbents for the development of hemosorbents and carriers of lithium-containing drugs.

The article presents the results of a study of the optical properties of cesium-containing quartzoid glasses (QG NFF-Cs) obtained as a result of the heat treatment of high-silica porous glasses (PGs) impregnated with aqueous solutions of CsNO3. It is established that the introduction of cesium into the composition of high-silica quartz glasses (QG NFF) led to the emergence of absorption bands at 332, 384, 388, 442, 492, 565, 567, 583, 586, 621, 635, 695, 696, and 703 nm, which are related to the absorption of cesium atoms. The introduction of cesium into the composition of the glass leads to a decrease in the absorbance QG NFF-Cs by 15–20

Composite materials (CMs) based on matrices of high-silica nanoporous glasses activated by silver and lanthanum are synthesized. It is established that, depending on the composition, the CM samples exhibit luminescence in the UV, violet-blue, green, red, and infrared spectral ranges due to the presence of isolated Ag+-ions, Ag+–Ag+ paired centers, molecular clusters (MCs) and nanoparticles (NPs) of silver, and oxygen vacancies in La2O3, together with various silicon defect centers.

New vitreous composite materials (CMs) with two magnetic subsystems are synthesized by impregnation magnetite-containing matrices from iron-containing nanoporous glasses in aqueous MnCl2 and H2C2O4 solutions and the subsequent formation of manganese oxides MnxOy (x = 1, 2, 3; y = 1, 2, 3, 4) inside the pore space of the matrices as a result of thermolysis of the reaction product of the dopants (MnC2O4). The chemical (elemental) and phase compositions, the valence-coordination state of iron and manganese, and the characteristics of the magnetic state of the synthesized CMs are studied and compared with the characteristics of nanoporous matrices.

Bismuth containing porous glasses (BPGs) were prepared on the basis of high-silica micro- and macroporous glasses and also of microporous glasses thermally treated at 750°C. The chemical composition of the glasses was determined by standard analytical methods and X-ray fluorescence analysis. Energy dispersive X-ray analysis showed that bismuth is predominantly formed at the half-thickness of the membranes. Characterization of the glass morphology was carried out by scanning electron microscopy. Their structural properties (specific surface area, volume porosity, structural resistance coefficient, average pore radius) and electrosurface ones (specific electrical conductivity, transport numbers of ions in the pore channels, electrokinetic potential) were studied in 10 −4 –10 −1 M KNO 3 solutions in a neutral pH range. The results were compared with similar properties of PG membranes not modified with bismuth(III) oxide. Porous glasses doped with bismuth oxide were found to restore their electrosurface characteristics in the neutral pH range in the concentration range of KNO 3 solutions under study.

Composite materials (CMs) based on porous glass matrices activated by yttrium in the presence of copper or bismuth are synthesized. It is established that, depending on the composition, the CM samples exhibit UV, blue-green, red, and infrared luminescence due to the presence of various centers, including Bi3+ and Cu+ ions, F centers in Y2O3, and molecular ions O_3^ - 2 associated with cation vacancies Y3+.

The spectral-optical and luminescence properties of bismuth-containing composite materials based on matrices of high-silica porous glasses are investigated. Luminescence spectra, luminescence excitation spectra, infrared transmission spectra (8000–4000 cm-1) depending on the composition of different types of matrices and sintering atmosphere (nitrogen, argon) of bismuth-containing composite materials were examined. It was found that the samples of bismuth-containing composite materials are characterized by UV (λem = 350 nm), blue-green (λem = 410–550 nm) and orange-red (λem = 600–725 nm) luminescence due to the presence of various bismuth active centers. The analysis of the spectra obtained by near-infrared spectroscopy demonstrates the formation of Bi2+ dimers of bismuth and bismuth active centers associated with silicon.

The spectral-optical and luminescence properties of bismuth-containing composite materials based on matrices of high-silica porous glasses are investigated. Luminescence spectra, luminescence excitation spectra, infrared transmission spectra (8000-4000 cm -1 ) depending on the composition of different types of matrices and sintering atmosphere (nitrogen, argon) of bismuth-containing composite materials were examined. It was found that the samples of bismuth-containing composite materials are characterized by UV (λ em =350 nm), blue-green (λ em =410-550 nm) and orange-red (λ em =600-725 nm) luminescence due to the presence of various bismuth active centers. The analysis of the spectra obtained by near-infrared spectroscopy demonstrates the formation of Bi 2+ dimers of bismuth and bismuth active centers associated with silicon. Keywords: Bismuth-containing composite materials, high-silica porous glass, near-infrared spectroscopy, luminescence, bismuth active centers.

Glasses with compositions 6Na 2 O⋅ x B 2 O 3 ⋅(86 – x )SiO 2 ⋅8Fe 2 O 3 , where x varies from 16 to 21 mol %, are preliminarily heat treated at a temperature of 550°C for 8–144 h and studied by scanning electron microscopy and dilatometry. The density and Vickers microhardness are measured, and the molar volume is calculated. It is found that in the course of heat treatment, a phase-separated structure with interpenetrating phases is formed in all studied glasses. As the SiO 2 content increases the diameter of the liquation channels decreases. It is shown that after 8 h, the coexisting liquid glass phases reach their equilibrium compositions, as indicated by the invariability of the glass transition temperature with an increase in the duration of heat treatment. With the maximum duration of heat treatment of 144 h for all the studied glasses, there is a decrease in the glass transition temperature of the low-viscosity phase and an increase in the density of glasses; this is accompanied by crystallization of the tridymite and cristobalite silica phases. The microhardness of the studied glasses does not depend on the SiO 2 content, and is about 2.5 GPa.

Composite materials (CMs) based on matrices of high-silica nanoporous glasses activated by bismuth and yttrium ions have been synthesized. A study was made of the spectral-optical properties (transmission, optical density) and optical absorption characteristics (Urbach energy) of CMs depending on the ratio of introduced bismuth and yttrium (the mass ratio of nitrates in Bi/Y solution from 1 : 1 to 10 : 1) and CM heat-treatment temperature (from 50 to 870°С). Optical spectroscopy revealed that bismuth is in various forms in composites: spherical colloidal particles of bismuth, Bi 3+ , Bi 2+ , Bi + ions; Bi_5^3 + polycations, bismuth dimers. It has been established that the Urbach energy increases with an increase in the heat-treatment temperature of CMs. It was found that an increase in the content of yttrium in CMs (ceteris paribus) leads to the disappearance or appearance of additional absorption bands in the range of 395–740 nm associated with bismuth, which is in various forms (spherical colloidal particles of bismuth, Bi 3+ , Bi 2+ , Bi + ions; Bi_5^3 + polycations, bismuth dimers). In the composites, near-IR region spectroscopy was used to identify vibrations characteristic of lattice vibrations in Y 2 O 3 , to absorb Bi + ions, Bi 0 and bismuth dimers Bi_2^ + .

Composite materials (CMs) based on matrices of high-silica nanoporous glasses (NPGs) activated by bismuth and yttrium ions are synthesized. The CMs are studied by IR spectroscopy (1000–400 cm–1), depending on the Bi/Y nitrate ratio in the solution (1 : 1 and 10 : 1) and the heat treatment temperature of the CMs (from 470 to 870°C). The method of IR spectroscopy in composites identifies vibrations characteristic of the cubic modification Y2O3 and for the monoclinic modification of bismuth oxide (α–Bi2O3); for vibrations of Bi–O and Bi–O–Bi bonds, as well as Bi3+ cations in [BiO6] and/or [Bio3] structural units; and for vibrations of Bi–O–Si bonds, and for Y–O–Y and Y–O bonds. It is established that an increase in the yttrium content in CMs heat-treated at 470 and 870°C, (all other things being equal) leads to the appearance of additional absorption bands at 564, 556, 432, and 424 cm–1, which may be related to the formation of the cubic phase Y2O3.

Glasses with compositions 6Na2O⋅xB2O3⋅(86 – x)SiO2⋅8Fe2O3, where x varies from 16 to 21 mol %, are preliminarily heat treated at a temperature of 550°C for 8–144 h and studied by scanning electron microscopy and dilatometry. The density and Vickers microhardness are measured, and the molar volume is calculated. It is found that in the course of heat treatment, a phase-separated structure with interpenetrating phases is formed in all studied glasses. As the SiO2 content increases the diameter of the liquation channels decreases. It is shown that after 8 h, the coexisting liquid glass phases reach their equilibrium compositions, as indicated by the invariability of the glass transition temperature with an increase in the duration of heat treatment. With the maximum duration of heat treatment of 144 h for all the studied glasses, there is a decrease in the glass transition temperature of the low-viscosity phase and an increase in the density of glasses; this is accompanied by crystallization of the tridymite and cristobalite silica phases. The microhardness of the studied glasses does not depend on the SiO2 content, and is about 2.5 GPa.