The results of previously published studies of the ion mobility, phase transitions, and electrophysical properties of tetrafluoroantimonates(iii) with heteroatomic cation sublattices composed of alkali metal and ammonium cations are analyzed, corrected, supplemented, and summarized. The influence of outer-sphere monovalent cations of different nature on the character of ion mobility, phase transitions, and conductivity in crystalline tetrafluoroantimonates(iii) is considered. It was found that phase transitions of most compounds in question are followed by the formation of superionic β-phases with a high conductivity of the order of 10−4–10−2 S cm−1 in the temperature range of 400–500 K.

Методом ЯМР 19F, 31P, 1Н в диапазоне температур 150-350 K и ЯМР с вращением под магическим углом (ВМУ) исследованы фосфатофторидные соединения MSbF(PO4)·H2O (M = Na, Rb, NH4). Определены виды ионных и молекулярных движений в соединениях, оценены энергии их активации. Установлено присутствие кислых фосфатных групп в соединениях натрия и рубидия. Спектры ЯМР ВМУ 19F фосфатофторидов сурьмы(III) схожи между собой вследствие близкого строения этих соединений, при этом множество сигналов в спектрах отражает разупорядоченность катионных подрешеток комплексов.

The Bi2O3/Bi2SiO5 heterostructures were obtained with various samples of silica as a precursor:on the basis of biogenic silica isolated from rice husk and rice straw and the silica of mineral ori-gin.A mixture of Bi(NO3)3 and SiO2 with a mass content of 15％was used for synthesizing all the samples.Fourier transform infrared(FT-IR)spectroscopy,scanning electron microscope(SEM),X-ray phase,X-ray fluorescence,and ultraviolet-visible diffused reflectance spectroscopy(UV-vis DRS)were used to systematically characterize as-obtained materials.Photodegradation of methyl orange in neutral aqueous solutions(pH=6.8)under UV irradiation was studied to evaluate their photocatalytic activities.Morphology,bandgaps,the value of the zero charge point,and photo-catalytic activity of the samples depended on the characteristics of the original silica.The degree of methyl orange degradation reached the maximum values(81％-85％)for samples based on precipitated silica from rice husks,straw,and the minimum value(16％)for a composite with thermal silica from rice straw.Composites based on thermal silica from rice husks and reagents from mineral raw materials did not statistically differ from each other in the degree of methyl orange degradation(67％-74％).

Phosphate-fluoride compounds MSbF(PO4)·H2O (M = Na, Rb, NH4) are studied by 19F, 31P, 1H NMR and by magic-angle spinning NMR (MAS NMR) in the temperature range 150-350 K. The types of ionic and molecular motions in these compounds are determined, their activation energies are estimated. The presence of acidic phosphate groups in sodium and rubidium compounds is established. The 19F MAS NMR spectra of antimony(III) phosphate fluorides are similar to each other due to the similar structure of these compounds, while the multitude of signals in the spectra indicates the disorder of cationic sublattices of the complexes.

The present analytical review has been revised according to the results of studies on the nature of ionic mobility and conductivity in complex antimony(III) fluorides with thallium cations. The studies have been carried out at the Institute of Chemistry of the Far Eastern Branch of the Russian Academy of Sciences. The relationship between the NMR data, ionic mobility, and conductivity of the compounds has been determined. The suggested mechanisms of the appearance of ionic mobility in the studied antimony fluorides have been investigated, and the factors determining their conductivity have been analyzed. The possibility of using antimony(III) fluorides with thallium(I) cations as functional materials has been discussed.

Oxide heterostructure photocatalysts Bi2O3/Bi2SiO5 have been prepared by mechanical stirring of anhydrous bismuth nitrate and biogenic silica from rice husk (BiSi‑X, Х = 1–50% SiO2) followed by calcination at 600°C. The materials were characterized by IR and electronic spectroscopy, X-ray powder diffraction and X-ray fluorescence analysis. Effect of silica content on sample morphology has been determined. Zero-charge point for theses materials is in the range from 7.20 (BiSi-1) to 8.64 (BiSi-50). The photocatalytic activity of the samples in the reaction of Methyl Orange degradation under exposure to UV and sun radiation has been studied. Degradation degree of Methyl Orange under sun light irradiation has been shown to be 27% and is independent of sample composition. The range of SiO2 content (23–39%) in photocatalysts samples, which provides 78–87% Methyl Orange degradation degree under UV irradiation, has been found.

This study shows the effect of conditions on methylene blue sorption from aqueous solutions using amorphous silicon dioxide obtained from rice husk by oxidative roasting with and without pre-treatment with 0.1 M HCl. Adsorption activity for methylene blue increases with increasing pH, reaching its maximum above the point of zero charge. Thermodynamic parameter values (ΔG298 > 0, ΔH < 0, ΔS > 0) indicate that methylene blue adsorption is exothermic and occurs with an increase in molecular mobility in the adsorption layer. The process is described by the Freundlich and Dubinin-Astakhov equations, which indicates that it is determined by both electrostatic interaction with active centers on the surface and the volumetric filling of micropores.

A comparative study of the microscopic morphology and chemical characteristics of spicules of Hexactinellids (Hexactinellida) with different structural features of the skeletons, as well as the freshwater Baikal sponge belonging to the class of common sponges (Demospongia), was carried out. The trace element composition of sponge spicules was determined by X-ray fluorescence spectrometry. The spicules of siliceous sponges contain many elements, arranged in decreasing order of concentration: Si, Ca, Fe, Cl, K, Zn, and others. It was shown that the surface layer of sea sponges contains mainly carbon (C), oxygen (O), and to a lesser extent nitrogen (N), silicon (Si), and sodium (Na). The spicules of the studied siliceous sponges can be divided into two groups according to the phase composition, namely one containing crystalline calcium compounds and one without them. Analysis of infrared absorption spectra allows us to conclude that the sponges Euplectella aspergillum, E. suberia and Dactylocalyx sp. contain silica partially bound to the organic matrix, while the silica skeleton of the sponges of the other group (Schulzeviella gigas, Sericolophus sp., Asconema setubalense, Sarostegia oculata, Farrea sp. and Lubomirskia baicalensis sp.) practically does not differ from the precipitated SiO2. This comparative study of the chemical composition of the skeletons of marine Hexactinellids and common freshwater sponge allows us to conclude that there are no fundamental differences in the chemical composition of spicules, and all of them can be used as a starting material for creating new composite silicon–organic functional materials.

Oxide heterostructure photocatalysts Bi 2 O 3 /Bi 2 SiO 5 have been prepared by mechanical stirring of anhydrous bismuth nitrate and biogenic silica from rice husk (BiSi‑X, Х = 1–50% SiO 2 ) followed by calcination at 600°C. The materials were characterized by IR and electronic spectroscopy, X-ray powder diffraction and X-ray fluorescence analysis. Effect of silica content on sample morphology has been determined. Zero-charge point for theses materials is in the range from 7.20 (BiSi-1) to 8.64 (BiSi-50). The photocatalytic activity of the samples in the reaction of Methyl Orange degradation under exposure to UV and sun radiation has been studied. Degradation degree of Methyl Orange under sun light irradiation has been shown to be 27% and is independent of sample composition. The range of SiO 2 content (23–39%) in photocatalysts samples, which provides 78–87% Methyl Orange degradation degree under UV irradiation, has been found.

This article studies inorganic components in Heliánthus tuberósus stems. Ash samples and extracts obtained at different pH values were examined. It is established that the extractant's nature has a significant effect on the yield of extractive substances from the ground stems: the greatest (45%) and the minimum (31%) yield was achieved by sodium hydroxide and distilled water, respectively. According to atomic absorption spectrometry, the main ions in the extracts obtained in different media are those of potassium, calcium, sodium, magnesium and iron. Following treatment of stems with solutions having different pH values, the mass fraction of ash varied from 0.4 to 2.3%. The smallest ash yield was observed for a stem sample after acid extraction. According to energy dispersive X-ray fluorescence spectrometry, all ash samples contained predominantly K, Ca, Si and P compounds. Acid hydrolysis produced the highest level of Si in samples, which allows this ash to be used as a silicon-containing material. The ash components of the core and outer part of the stem were compared with the initial sample. According to the nature of thermal decomposition, the initial sample and the outer shell were similar between themselves, though differing from the core. The ash content of the initial sample was 4.3%, with the ash content of the stem core being ~2 times higher than that of the outer shell (7 and 3.8%, respectively). The results of IR spectroscopy showed that splitting of bands in the IR spectra of ash samples depend on the part of the stem and the pre-treatment of raw materials at different pH values. The ash of the initial sample, core and outer shell, as well as the ash of the residues after the aqueous and alkaline hydrolysis of the stem, showed the absorption bands of carbonate groups. The IR spectra of the stem ash after acid extraction contained absorption bands characteristic of amorphous silicon dioxide. According to the conducted X-ray analysis, the studied ash samples were in an amorphous-crystal and crystalline state. The identification of phases was carried out.

The results of previously published NMR studies of amino acid complexes of antimony (iii) and indium(iii) fluorides are critically analyzed. Correlations between the NMR data, ion mobility, and structure of the complexes in question are considered. The interpretation of the low-temperature(19)F NMR spectra of amino acid complexes of antimony(iii) fluorides is corrected and certain figures were changed for better informativity. Mechanisms of the onset of ion mobility in the studied complexes of Sb(iii) and In(iii) fluorides are proposed and the possibility of application of these compounds in the design of functional materials is assessed.

The composition and morphology of hydrolytic lignin obtained from sunflower husk are studied before and after alkaline modification. The sorption properties of hydrolytic lignin towards Cr(VI) ions were studied under static conditions (at the solid to liquid phase ratio 1 : 1200, and a temperature of 20 degrees C) from the aqueous solutions of potassium dichromate with different initial concentrations of Cr(VI) ions (0.05-1.0 mg/L). Sorption kinetics was studied, and the analysis of the integral kinetic curves of sorption was carried out in accordance with chemical kinetic models.

Исследованы методами ДСК и ЯМР 19F, 1Н термические свойства и ионная подвижность (C2H6NO2)SbF4 во фториде сурьмы(III) с глицином в диапазоне температур 150—450 K. Проведено сравнение характера динамических процессов в комплексных фторидах (C2H6NO2)SbF4 и (C2H6NO2)3[InF6]. Приведен с некоторой коррекцией анализ данных ЯМР, изложенных ранее для соединения (GlyH)3[InF6]. Рассмотрена связь между данными ЯМР, ионной подвижностью и строением этих комплексов. Предложены механизмы появления ионной подвижности в комплексных фторидах Sb(III) и In(III) с глицином.

The results of a study into the acid-base surface properties of four silicon-containing ash samples obtained from the above-ground part of the field horsetail plant species (E. arvense L.) are presented. The samples were derived according to various schemes, comprising oxidative roasting both with and without preliminary treatments involving water and solutions of hydrochloric acid having a concentration of 0.1 and 1.0 mol/1. It was shown that the content of silicon dioxide in the samples varies from 33 to 98 % depending on the conditions of processing of raw materials. Preliminary processing of the raw material with an acid solution prior to roasting results in the formation of ash having a high silicon oxide content. The main impurity elements are calcium, potassium, magnesium, aluminum and iron. Samples prepared without preliminary treatment, as well as those treated with water, are characterised by a large amount of alkaline earth metal- and potassium oxides. A comparative characteristic of the surface condition of the obtained ash samples is given using pH measurements and the Hammett acidity function method. The pH measurements allow the integral acidity of the surface to be evaluated, while the Hammett method, based on the selective adsorption of acid-base indicators, is used to study the distribution of surface centres by acid-base properties. The pH values of the aqueous suspensions of neutral, alkaline or acidic samples are determined depending on the plant tissue processing scheme. It was found that the surface of the samples is characterised by the presence of Lewis acid(pKa +16.8), Bronsted basic- (pKa +7.15; +9.45) and acid- (pKa +2.5) active sites, the amount of which is determined by the composition of the samples. The high content of Lewis acid sites in the ash is associated with silicon atoms. The number of Bronsted sites depends on the horsetail treatment scheme. On the surface of samples obtained by oxidative roasting and those pretreated with water, the number of Bronsted active sites at pKa +2.5 and pKa +9.45 is higher compared to ash isolated following hydrolysis with hydrochloric acid. A comparative characteristic of the distribution curves of acid-base centres of silicon-containing ash samples obtained from the above-ground parts of field horsetail and rice straw is given, indicating their similarity.

Ion mobility and electrophysical properties in the compound (C2H6NO2)SbF4 have been studied by the methods of H-1, F-19 NMR and impedance spectroscopy. The types of ionic movements in the fluoride and proton sublattices of the compound have been determined within the temperature range 150-400 K, and their activation energy has been estimated. The mechanisms of the emergence of ionic mobility in tetrafluoroantimonate(III) with (GlyH)(+) have been suggested. Comparison of the electrophysical properties of three tetrafluoroantimonates(III) with different amino acids and ammonium cation has been presented.

Эколого-экономическая оценка комплексной схемы переработки рисовой шелухиНа сегодняшний день переработка отходов рисового производства стала важной технической и экологической проблемой.Но информации по эколого-экономической оценке предлагаемых проектов в научно-технической литературе немного.Цель данной работы заключалась в эколого-экономическом анализе комплексной схемы переработки рисовой шелухи с получением аморфного диоксида кремния, волокнистого остатка и щелочного лигнина.Объектом исследования была шелуха риса сорта Долинный, отобранная в пос.Тимирязевка Приморского края.В данной работе предложена технологическая схема

In the present study, the sol-gel technique helped to obtain Fe-containing samples with a base of amorphous silicon dioxide from rice husks RH-Fe and RH-Fe-300. These materials are characterized by IR spectroscopy, X-ray phase and X-ray spectral analysis. It was shown that the samples contain silicate structures Si-O-Si(Fe) and are in an amorphous state. Structure of the surface layers of RH-Fe-300 catalyst particles was established for the first time using X-ray photoelectron spectroscopy (XPS) and energy-dispersive spectra (EDX) methods. It was shown that the surface layers of the synthesized particles are oxygen depleted due to oxygen vacancies and silanol groups, therefore defects can form in its structure. Photocatalytic activity of the samples in the phenol oxidation reaction under ultraviolet and solar irradiation in the presence of hydrogen peroxide was studied. It was shown that the degree of phenol decomposition in the presence of RH-Fe for 24 hours under solar irradiation was 92%, in the presence of RH-Fe - 17%. Under two-stage irradiation (ultraviolet and solar), the percentage of phenol decomposition using both catalysts after a day amounted to more than 80%. It was established that RH-Fe-300 catalyst increases oxidation of phenolic compounds in alkaline rice husk hydrolysates under solar irradiation in the presence of hydrogen peroxide.

Thermal properties and ion mobility of (C2H6NO2)SbF4 in antimony(III) fluoride with glycine are studied by DSC, 19F NMR, and 1H NMR methods in the temperature region of 150–450 K. Dynamic processes in complex fluorides (C2H6NO2)SbF4 and (C2H6NO2)3[InF6] are juxtaposed. The NMR data reported earlier for compound (GlyH)3[InF6] are reanalyzed with some corrections. The relationship between NMR data, ion mobility, and the structure of these complexes is discussed. Possible mechanisms of ion mobility developing in complex fluorides Sb(III) and In(III) with glycine are proposed.

Sodium and potassium aluminosilicates samples are synthesized from solutions formed via the alkaline hydrolysis of rice straw. The fabricated samples are characterized by means of X-ray diffraction analysis and IR-spectroscopy, and their elemental composition, particle morphology, specific surface area, and thermal properties are determined. The sorption properties of the synthesized aluminosilicates with respect to Cs+ ions are investigated under static conditions. Kinetic curves and sorption isotherms are provided and a sorption kinetic model is described.