A homogeneous MgO-Y2O3 (50:50 vol%) nanocomposite semispherical green bodies with diameter up to 90 mm and relative green density of 46 % were successfully fabricated by the slip casting using nanopowder, synthesized by the glycine-nitrate method. To advance the rheological properties of MgO-Y2O3 aqueous suspensions, the effect of Dolapix CE64 and NH4PAA as dispersants was examined by viscosity measurements, sedimentation tests. A stable MgO-Y2O3 slurry showing near-Newtonian behavior was prepared with 30 wt% solid loading and 2 wt% of Dolapix CE64. Finally, sinterability of MgO-Y2O3 composite nanopowder was studied by vacuum sintering method for the first time. MgO-Y2O3 nanocomposite of complex shape vacuum-sintered at 1300 degrees C demonstrate optical transmittance of 45 % at the wavelength of 5.3 mu m, and the average grain size of MgO and Y2O3 components of 355 nm and 342 nm, respectively.

The work presents the results of research of compacted ceramic systems based on zirconium dioxide partially stabilized with cerium oxide and aluminium oxide, with additives of silicon carbide and silica; these materials could potentially be used as surgical implants or devices. The composite materials ZrO2-5wt.%CeO2-10wt.%SiC have shown higher biocompatibility with the human osteosarcoma cell line MG-63 than samples of compositions Al2O3-20wt.%SiO2- 10wt.%ZrO2 and ZrO2-5wt.%CeO2. Samples demonstrated hydrophilic behavior according to contact angle measurements. Zeta potential experiments showed that the nanoparticles were negatively charged in all cases in this study. Since the samples compacted in the temperature range of 1300-1600 degrees C are biocompatible with MG-63 cells, zirconia-based ceramics compacted research.

The paper presents the results of an investigations of the sintered zirconia ceramics that have been stabilized with Y2O3 2 O 3 and CeO2. 2 . The initial powders were synthesized via decomposition of the fluoride salts, which determined morphological features and dimensions of the particles. The specific electroconsolidation process, performed using the modified spark plasma sintering device, allowed for the retention of the nanoscale grain sizes and related properties of the sintered ceramic composites. It was found that the as-obtained materials with cerium oxide exhibited high bending strength of 609 MPa, by ca. 33 % higher than that of yttria-stabilized ones (410 MPa). In turn, the best combination of hardness and fracture toughness, K 1 & Scy; = 5.8 & Mcy; P & acy;& sdot; m 1/2 & acy; nd & Ncy; v = 14.8 GP & acy;, & acy;, respectively, exhibited ZrO2+3 2 +3 wt% Y2O3. 2 O 3 . This result can be attributed to the chemical composition and morphology of the powders, which in turn is influenced by the synthesis conditions and calcination time and temperatures, as well as to the sintering parameters. In particular, yttria-stabilized zirconia showed higher sensitivity to the variations of the sintering temperatures and holding times.

The paper presents a novel, low-cost and simple route for synthesis of TiOF2/CuO and F-TiO2/CuO out of fluoride solutions. The obtained materials after calcination can be used in various photocatalytic applications, e.g. in water treatment. It was demonstrated that control of synthesis process parameters, such as pH, allowed for synthesis of particles with different phase composition and properties. Thus, pH≤4 environment had created conditions for formation of two structures of TiOF2, hexagonal and cubic ones, as well as CuTiF6(H2O)4. Increase of Cu content promoted increase of the cubic c-TiOF2 phase. When the solutions exhibited pH>5, the synthesized particles consisted of (NH4)2TiF6·2H2O, (NH4)3TiF7, and (NH4)2СuF4·4H2O. Calcination above 300 °С provided formation of TiOF2/CuO particles, while elevated temperatures of 600 °С ensured appearance of F-TiO2/CuO material. It was found that higher copper concentrations resulted with higher fluoride percentage after calcination at 600 °С. It was also demonstrated that F-TiO2/CuO particles synthesized at рН≤4 exhibited energy band gap Eg of 3.3–3.25 eV, which decreased down to 2.85 eV for higher copper(II) oxide concentrations of 10 wt.%. Notably, the particles F-TiO2/CuO synthesized at pH>5 exhibited band gap Eg of 3.4–3.5 eV, which decreased down to 2.9 eV for higher CuO concentrations.

Titanium oxyfluoride TiOF2 finds a wide range of applications in photocatalytic processes, pigments, lithium ion batteries, etc. The present work proposes a novel, simple and productive TiOF2 synthesis route through hydrolysis of the titanium fluoride solution. It was demonstrated that the process resulted with the formation of two polymorph modifications, hexagonal h-TiOF2 (space group R3̅c) and cubic с-TiOF2 (space group Pm3̅m). It was found that the proportion between the resulting phases is dependent on synthesis conditions. In particular, the presence of hydrogen peroxide during titanium tetrafluoride hydrolysis provided formation of exclusively cubic TiOF2 phase. Moreover, the correlation between calcination temperature and phase composition of the synthesized titanium oxyfluoride samples was found. Band gap Eg was determined for the samples consisting of с-TiOF2 phase only, as well as for the mixture of both hexagonal and cubic modifications.

Crystals of solid solutions Cd0.9Zn0.1Te1-ySey with selenium concentration y = 0.02 – 0.07 were grown by the vertical Bridgman method under high pressure of argon gas (up to 26 atm) in graphite crucibles. The obtained crystals are characterized by the crystal structure similar to Cd0.9Zn0.1Te crystals. The distributions of the elemental composition in grown crystals were studied for different ways of raw materials loading. To obtain high-resistivity (detector) crystals an additional doping with Indium was carried out.

Single crystals of Co-doped magnesium-aluminum spinel (MALO:Co) are used for Q-switching of laser radiation at & lambda; = 1.54 & mu;m. Usually, they are grown by the Czochralski method from iridium crucibles that are too expensive. This investigation demonstrates the possibility of obtaining MALO:Co single crystals by the horizontal directional crystallization method using a molybdenum crucible in Ar + (CO, H2) protective reducing medium. The obtained MALO:Co crystals have the spinel structure of MgO ‧xAl2O3 with 1 & LE; x < 1.15, and the impurity of molybdenum in them does not exceed 0.019 wt%. Co2+ ions replace Mg2+ ions in the [MgO4] tetrahedral environment. This is confirmed by the broad absorption bands (& lambda;max & AP;600 nm and & lambda;max & AP; 1400 nm) in Vis-IR spectra. The absorption bands in the UV region of the spectrum are shown to originate from the complexes of point defects that can be eliminated by subsequent annealing in oxidizing/reducing environment. Experimentally shown is the possibility to obtain monoimpulses with the energy of -1-2 mJ and-10-15 ns duration at a wavelength of-1.54 & mu;m in passive Q-switches based on MALO:Co crystals.

The complex of polysaccharide chitosan with iodide acid was obtained and characterized. The possibility of obtaining iodine preparations in chitosan matrix with enhanced ability of chitosan to retain iodine is suggested. In this study to improve the stability of iodine, novel chitosan iodine complex was prepared by mixing chitosan with HI. Chitosan iodine complex was obtained as a solution, which can be treated to form bulk samples with open porosity and the enhanced ability to retain iodine. Silver-doped materials comprise insoluble silver iodide in amorphous or nanocrystalline form. The anti-bacterial as well as anti-fungal activity assessment of complexes of chitosan and iodine and chitosan and iodine with Ag has shown that chitosan iodide and chitosan iodide with Ag are more effective against fungi.

The effect of the conditions of synthesis on the formation of micro- and nanoparticles of zirconium dioxide from a fluoride solution has been studied. It is shown that the finest particles are formed by precipitation from dilute solutions with a zirconium concentration of 0.02–0.04 mol/L and impurities of polyvinyl alcohol at a mass ratio of m Zr : m PVC 1 : 0.1. To sinter ZrO 2 nanoparticles, it is proposed to use the electroconsolidation method in a vacuum to obtain ceramics with high values of the hardness and elastic modulus.

Method of composite materials formation based on particle-stabilized cerium dioxidezirconium nanopowders obtained from fluoride salt solutions has been investigated. The sintering ofthe powders was carried out by means of an electroconsolidation apparatus by hot pressing in avacuum chamber. X-ray phase analysis was performed on a Shimadzu XRD-6000 diffractometer.Phase analysis of the samples was carried out using the data base of the American Society for TestingMaterials. The surface morphology of the samples was investigated by scanning microscope JSM-6390LV. The most optimal method of nanopowders extraction was selected to produce solidnanostructured composites for bioengineering applications. Analysis of the microstructure of thesamples showed that the composite systems are composed of particles ranging in size from 100 nmto 1500 nm. The samples show pores and cracks, which can be associated with the passage of grainboundary diffusion in the process of electro-consolidation of the samples. Derivation of compositesbased on zirconium dioxide stabile at hot vacuum deposition by electrosintering makes it possible to obtain the high performance composites with high resistance to abrasion, hardness and thrustmodulus at a temperature of 1400 °C, a pressure of 30 MPa and a cycle time of 3 minutes. It wasfound that the method of electroconsolidation in vacuum provides the bonding of samples with highvalues of the Young’s modulus and friction strength. Mechanical characteristics of ceramic systemsbased on zirconium dioxide, molded with cerium oxide, have rather high values. The dependence ofchange in the relative specific gravity of the studied samples shows that the increase in temperatureof electroconsolidation, the overall level of composite density grows practically linearly, indicatinga good particle compatibility of the powders. The conducted studies allow us to assume that with thepurpose of further increasing of the properties of composites based on zirconium oxide, partiallystabilized by cerium dioxide, it is necessary to improve the homogeneity of the resulting sums andadd other oxides, in particular alumina oxide, alumina nitride, silicon oxide and magnesium oxide.

The mechanism of incorporation of aluminium oxide and aluminum oxyhydroxide into potassium dihydrogen phosphate (KDP) crystalline matrix is investigated. It was observed that: (1) aluminum phosphate is not formed on the surface of particles of aluminium oxide and aluminum oxyhydroxide particles in 1 M KDP solution irrespective of the treatment conditions and the size and phase composition of the particles, (2) phosphate groups are adsorbed on the surface of aluminum oxyhydroxide and aluminum oxide particles, and (3) a maximum observed at 1076 cm-1 of the absorption band in the 950-1200 cm-1 region of the infrared spectra is associated with the vibrations of phosphate ions adsorbed on the surface of the investigated particles. It is proposed that the phosphate groups adsorbed on the surface of aluminum oxyhydroxide and aluminum oxide particles interact with the phosphate groups of the growing KDP crystals by means of creation of hydrogen bonds between them, and that this interaction results in the "attraction" of the particles to the surface of the growing crystal and its subsequent overgrowth.

Prevention of water from the pollution with hard metals ions and radionuclides, as well as water treatment motivate for the research and investigations in the field of the new effective sorbents. This paper presents the results on (NH4)(2)TiOF4 sorption properties in the context of the synthesis conditions and related particle formation. It was demonstrated that proper control of the precipitation process could result with either spherical particles of 50-80 nm diameter or rod-like particles of length up to 10 mu m. Moreover, it was found that respective of synthesis conditions, (NH4)(2)TiOF4 particles exhibited high sorption efficiency towards lanthanum, yttrium, scandium, europium, and cerium, above 95% at pH greater than 3. The highest sorption capacity performed spherical particles synthesized at room temperature. Their respective capacities towards cerium, europium, lanthanum, yttrium, and scandium at pH 5.5 were 350, 300, 240, 200, and 270 mg/g. The researches indicated that increased precipitation temperature reduced sorption capacity by 50% and even 70% due to the larger dimensions of the obtained particles. The tests performed for static and dynamic equilibrium revealed selectivity of the (NH4)2TiOF4 particles towards the rare earth elements in the presence of divalent and monovalent ions.

The paper describes researches on new materials based on the MnO(OH)-modified diatomite synthesized for application in sorption of Eu, Co and Sr from aqueous solutions. The material was obtained through precipitation of MnO(OH) from initial solution on the surface of diatomite particles using MnO(OH) concentrations from 0.5 up to 10 wt%. Efficiency and sorption capacity were investigated, especially towards europium, cobalt and strontium solved in water. Since sorption efficiency of the pure diatomite is not high, it was demonstrated that its surface modification with MnO(OH) increased sorption capacity towards several heavy metals up to 95% and 98% in the range of pH between 4 and 8. Higher concentrations of MnO(OH) deposited on the diatomite particles surface increased sorption capacity. It was found that 1 wt% of MnO(OH) provided capacity 15, 10, and 17 mg/g towards Co, Eu, and Sr, respectively. Further, 10 wt% concentration of MnO(OH) ensured respective capacities toward the same elements 28, 16, and 64 mg/g. These results demonstrated capability of surface-modified with MnO(OH) diatomite particles to remove ions of divalent and trivalent metals out of the potable water.

In the paper, synthesis process of the TiO2 particles was discussed, from the fluoride solution, through TiO2·nH2O gel thermal precipitation and decomposition, and its impact on the further sintering of the obtained powders. It was demonstrated that the main phase of the obtained titania was anatase. Morphology of the obtained TiO2 can be controlled through variations of the precipitation temperature and the emulsifier concentration. It was found that the addition of the chloride ions during gel formation caused crystallization of the (NH4)2TiOF4 phase. When it underwent decomposition under heating, agglomerated particles in form of rods several micrometers long were synthesized. Obtained powders were sintered, and both the sintering process and the final bulk structures were examined. The results indicated the lowest microhardness of 540 kg/mm2 in the specimens prepared out of the powders synthesized without emulsifier, while the highest hardness of 1450 kg/mm2 was reached when the TiO2 particles had been precipitated at room temperature with emulsifier proportion С(Ti):C(OР9) = 1:0.5. However, further increase of the emulsifier concentration led to the decrease of hardness.

New composite materials were obtained based on chitosan iodide and organic dyes – methylene blue and fuchsine in fucorcin (Castellani liquid) – by using a simple synthetic procedure. The materials were characterised by scanning electron microscopy, X-ray diffraction, temperature-programmed desorption mass spectrometry, infrared spectroscopy and visible and ultraviolet light spectroscopy. The dyes in the composites were distributed uniformly and did not form separate phases. These composites could form structured porous sponges and films and therefore be used in various fields of application. The materials displayed antibacterial activity against antibiotic resistant gram-positive and gram-negative bacteria.

We report the synthesis and evaluation of inclusion complexes between mefenamic acid (MFA) and 2-hydroxypropy1-13-cyclodextrin (HP-13-CD). The phase solubility studies reveal that MFA forms a complex with the HP-13-CD at a 1:1 molar ratio that was also confirmed by UV-vis spectral data (Job's plots). Characterizations of the prepared host-guest type solid complexes using a reliable spectroscopic and calorimetric methods indicate that MFA is found inside the cavity of the HP-13 -CD. Obtained thermodynamic parameters for MFA/HP-13-CD complex formation show that MFA inclusion in HP-13-CD cavities is favorable, spontaneous exothermic and enthalpy-driven process. The stability constant KS for MFA/HP-13-CD complexes determined from the Benesi-Hildebrand equation using fluorescence spectral data is adequate for the formation of an inclusion complex indicates that a fast MFA drug release from MFA/HP-13-CD complex should be expected. The presented results show the MFA/HP-13-CD complex as an effective new approach to design a novel formulation for pharmaceutical applications.

In our work, chitin was isolated from the adult grain moth biomass, its properties were studied, and a nanoform was obtained. The moth chitin differs from the classic crab chitin produced on an industrial scale by a lower degree of crystallinity, hygroscopicity, and a higher content of amino groups, which makes it easier to obtain nanoforms. Chitin nanoflbrils can be used for various medical applications.

In the paper, investigation results of the uptake efficiency of radionuclides 60Co, 90Sr, and 137Cs dissolved in water onto iron oxides α-Fe2O3 and Fe3O4 are presented. It was found that sorption efficiency increased for higher pH values. Independent of the oxide nature, the uptake characteristics are the best toward 60Co and the worst toward 137Cs, forming the row as follows: 60Co > 90Sr > 137Cs. The highest sorption ability at pH 9 was found for magnetite Fe3O4, which was 93%, 73%, and 26% toward 60Co, 90Sr, and 137Cs, respectively, while the respective percentages for hematite α-Fe2O3 were 85%, 41%, and 18%. It was assumed that the main sorption mechanism was ion exchange. That may explain some decrease of the sorption efficiency in drinking water due to the interfering presence of magnesium and calcium cations. The obtained results indicated the feasibility of the tested sorbents and their merits, especially in terms of relatively high uptake coefficients, low costs, availability, and lack of toxicity.