The paper presents the results of a study of the porous structure and sorption characteristics of technogenic foam silicate obtained in the process of complex processing of waste ore raw materials and modified in the process of thermochemical treatment in the gas phase of hydrocarbons. The parameters of thermochemical modification of the surface of foam silicate to obtain an oleophilic adsorbent for the removing of petroleum products from aqueous media, as well as the modes of its regeneration, have been determined. It has been established that the degree of extraction of petroleum products from water by the resulting adsorbent under static conditions is 99.8

Single crystals of hexahydrates of divalent fluoridotitanates MTiF6·6H2O (M = Mn, Co, Ni, Zn) are synthesized. Their crystal structures are determined by X-ray diffraction at room temperature (RT-structure) and below the phase transition (LT structure). The phase transition is accompanied by a transformation of the disordered trigonal lattice into the ordered monoclinic one. The initial RT-structures differ in the set and strength of O–H⋯F hydrogen bonds linking isolated [M(H2O)6]2+ and [TiF6]2– octahedra into a 3D framework. There is a correlation between the strength of hydrogen bonds and the thermal behavior of the complexes.

Синтезированы монокристаллы гексагидратов фторидотитанатов двухвалентных металлов MTiF6∙6H2O (M = Mn, Co, Ni, Zn). Методом рентгеновской дифракции определены их кристаллические структуры при комнатной температуре (RT-структура) и ниже фазового перехода (LT-структура), сопровождающегося трансформацией тригональной разупорядоченной решетки в моноклинную упорядоченную. Исходные RT-cтруктуры различаются набором и силой водородных O–H∙∙∙F связей, объединяющих изолированные [M(H2O)6]2+ и [TiF6]2– октаэдры в трехмерный каркас. Наблюдается корреляция между силой водородных связей и термическим поведением комплексов.

The interaction of tungsten mineral raw materials with a mixture of NH 4 HF 2 and (NH 4 ) 2 SO 4 upon heating was studied. It was determined that, first, at temperatures up to 200°C, the incoming components are fluorinated to form complex and simple fluorides. A further increase in temperature is accompanied by the decomposition of ammonium sulfate to form NH 4 HSO 4 , which leads to the conversion of fluorides into sulfates and of the tungsten ammonium fluoride complex into tungstic acid H 2 WO 4 . It was shown that water leaching of the product of the decomposition of tungsten-containing mineral raw materials with a mixture of NH 4 HF 2 and (NH 4 ) 2 SO 4 makes it possible to extract tungsten from mineral raw materials in the form of the commercial product WO 3 .

Fluoride metal-organic frameworks (MOFs) based on pillared [NbOF5](2-) anion have been recently received research attention as ultramicroporous materials for gas storage and separation. The trans-directing property of the NbOF5 octahedron plays a significant role in designing mixed metal oxyfluoride compounds composed of the alternating transition metal polyhedra, which are linked via oxide and fluoride ligands. Mixed metal CuNbOF5 center dot 4H(2)O is the only unique example when the trans-directing properties of [NbOF5](2-) are realized in the formation of a strong O-H.F hydrogen bond (HB). Well-shaped single crystals of this compound were grown and their structure was refined by X-ray diffraction. Under quasi-isobaric conditions, a phase transition at 88 degrees C takes place, which is associated with the weakening of HBs and formation of ordinary chains through conventional trans-(O,F) bridges. The character of hydrogen bonding in CuNbOF5 center dot 4H(2)O affects its thermal behavior described by the dehydration and pyrohydrolysis processes.

An effective sorption material for the immobilization of cobalt radionuclides into highly safe and reliable solid-state matrices is proposed. The resulting silicate sorbent CaSiO3 had an amorphous mesoporous structure (ABET 53 m2/g) and a sorption capacity Co ions of 3.32 mmol/g. The physico-chemical characteristics of the CaCoSi2O6 sample obtained after Co2+ ions sorption were studied using XRD, N2 and Ar adsorption-desorption, SEM-EDX and TG/DTA methods. Solid-state silicate matrices characterized by high density values (2.86-3.16 g/cm3), compressive strength (150-637 MPa) and Vickers microhardness (1.80-5.25 GPa) were obtained by spark plasma sintering (SPS). The sample obtained at 1000 degrees C had the lowest values of Co2+ ions leaching (RCo ~10-7 g/(cm2xday)) and diffusion coefficient (De 1.73 x10-17 cm2/s) from silicate matrices. Thus, the obtained CaCoSi2O6 silicate matrices saturated with Co ions comply with the regulatory requirements of GOST R 50926-96 and ANSI/ANS 16.1 for 60Co immobilization. (c) 2022 Elsevier B.V. All rights reserved.

A new approach to the use of rice straw as a difficult-to-recycle agricultural waste was proposed. Potassium aluminosilicate was obtained by spark plasma sintering as an effective material for subsequent immobilization of 137Cs into a solid-state matrix. The sorption properties of potassium aluminosilicate to 137Cs from aqueous solutions were studied. The effect of the synthesis temperature on the phase composition, microstructure, and rate of cesium leaching from samples obtained at 800–1000 °C and a pressure of 25 MPa was investigated. It was shown that the positive dynamics of compaction was characteristic of glass ceramics throughout the sintering. Glass ceramics RS-(K,Cs)AlSi3O8 obtained by the SPS method at 1000 °C for 5 min was characterized by a high density of ∼2.62 g/cm3, Vickers hardness ∼ 2.1 GPa, compressive strength ∼231.3 MPa and the rate of cesium ions leaching of ∼1.37 × 10−7 g cm−2·day−1. The proposed approach makes it possible to safe dispose of rice straw and reduce emissions into the atmosphere of microdisperse amorphous silica, which is formed during its combustion and causes respiratory diseases, including cancer. In addition, the obtained is perspective to solve the problem of recycling long-lived 137Cs radionuclides formed during the operation of nuclear power plants into solid-state matrices.

The results of studying the solid-phase reaction of a datolite concentrate with ammonium sulfate are described. It is found that the reactions of the main components of the concentrate with (NH 4 ) 2 SO 4 begin when the temperature of thermal decomposition of (NH 4 ) 2 SO 4 is reached (about 300°C) and continue at the highest rate in the temperature range of 340–365°C. Conditions are determined for transferring the main amount of boron into the solution and separating it from the accompanying components in the form of H 3 BO 3 .

The conditions for the synthesis of two polymorph modifications of ammonium tetrafluorobismutate(III) from the heated water solution of ammonium fluoride (bifluoride) were studied with different BiF 3 :NH 4 HF 2 (NH 4 F) reagent concentrations. The crystal structure of monoclinic β–NH 4 BiF 4 ( a =8.1014(3), b =6.6208(2), c =8.1045(3) Å, β =111.003(1)°, sp.gr. P 2 1 / c ) was determined for the first time. The structure of α–NH 4 BiF 4 ( a = 8.3185(6), b = 7.5902(6), c = 6.4866(5) Å, β = 93.687(1)°, sp.gr. P 2 1 / c ) was refined. Both polymorph modifications have layered structures with a single nine-coordinated bismuth site. The thermal decomposition of NH 4 BiF 4 was studied and two products of the decomposition having a cubic structure were isolated. The fluorine and ammonium mobility in obtained phases was probed with 1 H, 19 F NMR.

An effective sorption material for cesium radionuclides immobilization in highly safe and reliable solid-state matrices was proposed. Prepared aluminosilicate (KAlSi3O8) adsorbent had amorphous mesoporous structure and Cs+ ions sorption capacity of similar to 3.7 mmol/g . The physical-chemical characteristics of (Cs, K)AlSi3O8 sample saturated with Cs+ ions were studied using XRD, FT-IR, SEM-EDX, and DTA-TG methods. Firstly, solid-state aluminosilicate matrices were obtained using spark plasma sintering (SPS) technology with high values of relative density (up to 99.9%), compressive strength (31.3-79.2 MPa), and Vickers microhardness (0.9-5.3 GPa). The sample obtained at 1000 degrees C had a low value of Cs+ leaching from matrices (R-Cs within the range of 10(-7) g cm(-2).day(-1)) and cesium diffusion coefficient (D-e 9.07 x 10(-14) cm(2)/s). It was shown that prepared aluminosilicate cesium matrices comply with regulatory requirements of GOST R 50926-96 and ANSI/ANS 16.1.

The processes of solid-phase interaction between calcium and rare-earth fluorides and ammonium sulfate have been studied. Based on thermogravimetric and X-ray diffraction data, the stages and intermediate products of these processes have been identified. It has been established that the heating of ammonium sulfate in a mixture with calcium and rare-earth fluorides to 400°C leads to the conversion of the latter into sulfates.

Ion mobility and conductivity of Rb0.4Bi0.60-xInxF2.2 (x = 0, 0.05, 0.1, 0.15) solid solutions with fluorite structure have been investigated using F-19 NMR, X-ray diffraction and impedance spectroscopy methods. Several types of fluoride ions in the solid solution composition were found by analyzing the F-19 NMR spectra at 150 K. Attribution of fluoride ions to the specific sublattice was carried out by deconvolution of the spectra. Diffusion of the fluoride ions above 300-350 K was found to be the dominating type of ionic motion in the fluoride sublattice of solid solutions under study. The influence of the size and polarizability of trivalent cations on the nature of ionic mobility in solid solutions in the RbF-BiF3-InF3 ternary system is discussed. Due to the high ionic conductivity of these solid solutions (1.6x10(-3) and 7.3x10(-4) S/cm at 500 K for x = 0.10 and 0.05), they can be considered as superionic conductors.

New glasses have been synthesized in the InF3-BaF2-BiF3-BiPO4 system. The introduction of the phosphate component into fluoroindate glass increases the resistance of the glass to crystallization, but the presence of phosphate polyhedra in the glass structure, even in small amounts, reduces the transmission region. It is shown that glasses in the InF3-BaF2-BiF3-BiPO4 system can be a convenient base for obtaining glass-crystalline materials consisting of an oxide glass matrix with crystalline fluoride phases. Luminescence was detected in the near IR region (1182 nm) in the glasses under discussion.

A series of the bismuth containing fluorozirconate glasses are synthesized in the ZrF4-BiF3-BiPO4, ZrF4-BiF3-MFBiPO4 (M Li, Na, K) and ZrF4-BiF3-Ba(Pb)F-2-BiPO4 systems. The introduction of the BiPO4 component into the bismuthfluorozirconate system led to increases in the glass transition and crystallization onset temperatures, thermal stability and crystallization resistance of the glass. The possibility of obtaining glassy matrices with crystallized phases of certain compositions under heat treatment of the discussed systems has been shown. Glass networks are built of fluorozirconate, fluorobismuth and phosphate polyhedra. The presence of phosphate polyhedra decreases the transmission region. It was found that 40ZrF(4)-50BiF(3)-10BiPO(4) glass exhibits luminescent properties in the near-IR region at 1169 nm when excited by radiation with wavelengths of 420 and 370 nm.

This article describes an original sol-gel (template) method for the synthesis of a dispersed form of nanostructured wollastonite (CaSiO3), its gold nanoparticles (40-60 nm) functionalized form CaSiO3/Au-NPs, and its composite in the composition with 20 mass% of hydroxyapatite CaSiO3/HAp and synthetic hydroxyapatite, that are widely used in medicine for the reconstruction and regeneration of bone defects. The method provides the formation of porous silica carcass in samples with an average pore size of 100-160 nm due to the application of polymer siloxane-acrylate as a pore-forming template. The authors studied the processes of template destruction and phase formation in the composition of samples using TGA/DTA/DSC (thermogravimetric analysis/differential thermal analysis/differential scanning calorimetry), and XRD (X-ray diffraction analysis). The methods of SEM (scanning electron microscopy), low-temperature nitrogen adsorption, and mercury porosimetry were used to identify the morphology and study the structural characteristics (Sspec and Vpor, pore size distribution) for dispersed nanostructured samples based on wollastonite and hydroxyapatite. An "in vitro" model was used to study the functional activity (metabolism and cytokine production) of innate immune cells (neutrophils and macrophages) in contact with the obtained samples and to evaluate the viability of cells, the activity of ATPase activity, the number of cationic proteins, and apoptosis of cells. The study is novel for these systems and contributes to the existing knowledge on the biocompatibility for "in vivo" model, which provides a complex evaluation of the quality of wollastonite biomaterials used as grafts.

The data on investigation of the possibility of breakdown of ilmenite concentrate of the Ariadnensky deposit in Primorsky Krai with ammonium sulfate are presented in the article. For study the ilmenite concentrate and ammonium sulfate interaction, the concentrate and (NH4)2SO4 were mixed based on the formation of sulfates of the main components of the concentrate and then double sulfates of the components of the concentrate and ammonium. The interaction was carried out in glassy carbon crucibles, which were placed in a muffle furnace controller company Nabertherm GmbH (Germany). The weight of sample was 10–40 g. Thermogravimetry, X-ray diffraction and atomic absorption analyses were used in the study. It was found that when the temperature of thermal decomposition of (NH4)2SO4 (3000С) is reached, the interaction of the main components of the concentrate with (NH4)2SO4 begins and proceeds in the temperature range of 300-3600С with the formation of a mixture of double salts well soluble in water - ammonium sulfate and iron compounds (NH4)2Fe2(SO4)3 and NH4Fe(SO4)2 and ammonium sulfate and titanyl of the composition (NH4)2TiO(SO4)2. The interaction at a temperature above 3600С leads to thermal decomposition of the formed double sulfates of ammonium and titanyl and ammonium and iron to sulfates and then oxides. It was shown that water leaching of the product of the interaction of ilmenite concentrate with (NH4)2SO4 at 3600С allows to extract practically all titanium and the bulk of iron to water in the form of well soluble double salts. The conditions for the titanium dioxide separation in the form of anatase from the water leaching solution were found.

The article presents an original way of getting porous and mechanically strong CaSiO3-HAp ceramics, which is highly desirable for bone-ceramic implants in bone restoration surgery. The method combines wet and solid-phase approaches of inorganic synthesis: sol-gel (template) technology to produce the amorphous xonotlite (Ca6Si6O17·2OH) as the raw material, followed by its spark plasma sintering–reactive synthesis (SPS-RS) into ceramics. Formation of both crystalline wollastonite (CaSiO3) and hydroxyapatite (Ca10(PO4)6(OH)2) occurs “in situ” under SPS conditions, which is the main novelty of the method, due to combining the solid-phase transitions of the amorphous xonotlite with the chemical reaction within the powder mixture between CaO and CaHPO4. Formation of pristine HAp and its composite derivative with wollastonite was studied by means of TGA and XRD with the temperatures of the “in situ” interactions also determined. A facile route to tailor a macroporous structure is suggested, with polymer (siloxane-acrylate latex) and carbon (fibers and powder) fillers being used as the pore-forming templates. Microbial tests were carried out to reveal the morphological features of the bacterial film Pseudomonas aeruginosa that formed on the surface of the ceramics, depending on the content of HAp (0, 20, and 50 wt%).