The incomplete inner subshell (i.e., 4f) makes rare-earth elements (REE) different from other elements in the periodic table. Incorporating an atomic number across the lanthanide group merely adds an extra electron to the inner 4f rather than the outer shell. To prove this, we tested Nd and Ce doped vanadates as facile and convenient way for simultaneous detection of para-nitrophenol and 2,4,6-trichlophenol via the electrochemical way over modified glassy carbon (GC) electrode (GC/CeVO4; NdVO4). For the materials preparation convenient single-step hydrothermal procedure was developed and resulting material (CeVO4) demonstrate high grade of crystallinity with average size through the crystalline plain (200) equal to 57.4 nm and absence of any additional phases. GC/CeVO4 electrode was applied for the pioneering study of simultaneous determination of p-nitrophenol (pNP) and 2,4,6-trichlorophenol (TCP) via the SWV method in Britton-Robinson buffer solution at pH5. The developed method of evaluation demonstrate the span of p-nitrophenol calibration graph in range from 0.2 mu M to 100 mu M with the detection limit 0.058 mu M in the presence of 100 mu M of 2,4,6-trichlorophenol. The TCP calibration graph comprise concentrations in range from 0.2 mu M to 60 mu M with the detection limit 0.111 mu M in the presence of 100 mu M of pNP. Simultaneous determination of pNP and TCP may be performed in range from 0.2 mu M up to 60 mu M with the limits of detection equal to 0.091 mu M for pNP and 0.151 mu M for TCP. GC/CeVO4 electrode demonstrate 9.2 % deviation of pNP signal and 11.3 % of TCP signal deviation within 8 cycles of measurement. Interference study was held with K+, Mg2+, Sr2+, ascorbic acid, citric acid, urea, phenol, resorcinol each taken in 10-fold excess, while the electrode demonstrated retention of signal level not less than 75 % of initial. Application of electrode to tap water investigation had shown the 15 % deviation of pNP signal while the TCP signal stays intact. The abovementioned makes GC/CeVO4 electrode promising for the evaluation of aromatics in wastewaters.

The sorption of organic dyes was studied by the methods of X-ray phase analysis, spectrophotometry, and infrared spectroscopy, using methylene orange (MO) and methylene blue (MB) as a case study, by layered double hydroxide (LDH) of magnesium and aluminum with a specific surface area of ~ 200 m2/g, obtained by the low saturation method. It has been shown that the sorption capacity of lay-ered double hydroxide in the case of a solution of MO reaches 82%, and for a solution of MB it is 15%. It has been experimentally established that the sorption of dyes does not lead to structural changes in LDH, as evidenced by the absence of any significant changes in the X-ray diffraction pat-tern of the samples before and after sorption. An assumption has been made that the sorption of dyes occurs on the surface of the sample (physical sorption). The theory of physical sorption is supported by the large specific surface area of the layered double hydroxide. Possible reasons for different sorp-tion capacities for MO and MB solutions have been analyzed.

— Properties of porous materials prepared from glasses of the Na 2 O–B 2 O 3 –SiO 2 –GeO 2 system have been studied using low-temperature nitrogen adsorption/desorption measurements. The results demonstrate that germanium substitution for silicon in the glasses studied leads to an increase in pore volume at SiO 2 /GeO 2 ratios of down to 0.5. The porous glass with this composition has the largest specific surface area and micro- and mesopore volumes. We assume that the observed changes in the porosity parameters of glass in the case of complete germanium substitution for silicon are related to structural features of the borogermanate glass network, associated with B–O–B bond breaking and the formation of non-bridging oxygen atoms.

Magnesium–aluminum layered double hydroxides and mixed oxides based on them were obtained by high and low supersaturation methods and analyzed. It was shown that the phase composition and formation of nano-sized particles with a large surface area is significantly affected by the rate of introduction of magnesium–aluminum systems into the medium of the precipitated material. All of the obtained samples were studied by thermogravimetric analysis with mass-spectrometric detection, X-ray diffractometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and infrared spectroscopy.

Методом низкотемпературной адсорбции/десорбции азота определены характеристики пористых материалов, полученных из стекол системы Na 2 O–B 2 O 3 –SiO 2 –GeO 2 . Показано, что при замещении кремния на германий наблюдается увеличение объема пор в изученных стеклах вплоть до состава с соотношением SiO 2 /GeO 2 , равным 0.5. Пористое стекло этого состава характеризуется наибольшими удельной поверхностью, объемами микро- и мезопор. Кроме того, мы предположили, что изменение пористых характеристик стекла в случае полного замещения кремния на германий связано со структурными особенностями борогерманатной сетки, обусловленными разрывом связей B–O–B с образованием немостиковых атомов кислорода.

Adjusting the morphological characteristics of a material can result in improved electrocatalytic capabilities of the material itself. An example of this is the introduction of rare-earth elements into the borate structure, which gives a new perspective on the possibilities of this type of material in the field of (bio)sensing. In this paper, we present the preparation of borates including La, Nd and Dy and their application for the modification of a glassy carbon electrode, which is used for the non-enzymatic detection of a biologically relevant molecule, vitamin B6 (pyridoxine). Compared with the others, dysprosium borate has the best electrocatalytic performance, showing the highest current and the lowest impedance, respectively, as determined using cyclic voltammetry and impedance tests. Quantitative testing of B6 was performed in DPV mode in a Britton–Robinson buffer solution with a pH of 6 and an oxidation potential of about +0.8 V. The calibration graph for the evaluation of B6 has a linear range from 1 to 100 μM, with a correlation coefficient of 0.9985 and a detection limit of 0.051 μM. The DyBO3-modified electrode can be used repeatedly, retaining more than 90% of the initial signal level after six cycles. The satisfactory selectivity offered a potential practical application of the chosen method for the monitoring of pyridoxine in artificially prepared biological fluids with acceptable recovery. In light of all the obtained results, this paper shows an important approach for the successful design of electrocatalysts with tuned architecture and opens new strategies for the development of materials for the needs of electrochemical (bio)sensing.

Black-red and orange magnesium perylene-3,4,9,10-tetracarboxylate species are synthesized in the ion-exchange reaction at room temperature and by boiling an aqueous solution, respectively. Upon heating the two species to 500°C in argon, they reversibly lose 19–27 wt % of their crystallization water, and the products become black. X-ray diffraction analysis results show the preservation of the layered structure upon heating, which is confirmed via transmission electron microscopy. Exposure to a humid atmosphere rehydrates and restores the original structure. Thermolysis to 1000°С in argon produces a composite of MgO nanoparticles in a porous glassy carbon matrix. The stability of perylenetetracarboxylates up to 500°C makes them a promising candidate for synthesizing metal–organic frameworks.

In the present paper the composite materials based on Fe3O4/TiO2 and Fe3O4/SiO2/TiO2 ox-ides, synthesized by the hydrothermal peroxide method, were studied. At the first stage, magnet-ite nanoparticles were precipitated by ammonium hydroxide from a mixture of aqueous solutions of iron(II) sulfate and iron(III) chloride under continuous exposure to ultrasound, after which they were washed with distilled water. At the second stage, the resulting hydrated magnetite particles were stabilized with polyvinyl alcohol (PVA) by dispersing them under the action of ultrasound in a hot saturated aqueous PVA solution. At the third stage, the photocatalytically active particles based on titanium oxide were introduced into the composite by mixing the stabilized magnetite suspension with an aqueous solution of peroxotitanic acid (optionally introducing a sol of silicic acid), followed by hydrothermal treatment of the mixture at 180°C for 24 hours, washing, and drying under vacuum followed by calcination in a muffle furnace. The effect of the molar content of iron and titanium on the properties of the samples, the introduction of silicon dioxide into them, as well as various calcination temperatures, were studied. The photocatalytic properties of the synthesized samples during photodegradation of methyl orange and methylene blue, as well as their magnetic recovery from suspension, were studied. The physicochemical characterization of the samples was performed using high-resolution scanning electron microscopy, energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, powder X-ray diffraction, low-temperature nitrogen sorption porosimetry, inductively coupled plasma mass spectrometry, thermal analysis (TG–DSC), combined with mass spectrometry of gaseous thermolysis products. The optimal conditions for the synthesis of composites exhibiting the best combination of photocatalytic and magnetic properties were determined. The resulting photocatalysts can be used to purify water from dyes, followed by extraction using a magnet

Whole-grain food ingredients enable the most balanced food products to be obtained, thus forming an important part of a healthy and sustainable diet. Wheat and barley grains are a traditional source of food ingredients for breads, breakfasts, drinks, and snacks in Russia. Such foods are suitable for all ages with many health benefits. However, the modern metropolitan citizen consumes large quantities of refined cereal products, thus impoverishing their diet. An alternative in dietary fortification could be sprouted and fermented food ingredients with an increased nutritional value. The present work was carried out to study the effect of a combination of germination with ultrasound treatment and fermentation with a complex starter of cereal crops on antioxidant activity and γ-aminobutyric acid content of food ingredients with the possibility of using them in the matrix of food products. In order to obtain germinated food ingredients, we used crops with the highest yield in the Ural region (Russia): two samples of soft spring wheat (Triticum aestivum L.) and a sample of spring barley grain (Hordeum vulgare L.). Obtaining food ingredients was divided into successive stages: ultrasonic treatment (22 ± 1.25 kHz) was performed by means of changing power and length of time (245 W/L, intensity for 5 min); germination and fermentation used complex starter “Vivo Probio”. The proposed technology of germination with haunting fermentation of cereal crops resulted in food ingredients with a more uniform distribution of granulometric composition, a low proportion of fine particles (4.62–104.60 µm) (p < 0.05) and large particles (418.60–592.00 µm) (p < 0.05). The particle size range (31.11–248.90 μm) (p < 0.05) was predominant. The germination and fermentation process resulted in 26 to 57% (p < 0.05) lower phytic acid content, 35 to 68% (p < 0.05) higher flavonoid content, 31 to 51% (p < 0.05) higher total antioxidant activity, 42.4 to 93.9% (p < 0.05) higher assimilability, and 3.1 to 4.7 times (p < 0.05) higher γ-aminobutyric acid content, which will allow production of food products with pronounced preventive action. The data was analyzed via one-way ANOVA analysis of variance using the free web-based software. The combination of the germination process with ultrasound treatment and subsequent fermentation with a complex starter can be used to support the development of healthful food products with increased GABA and antioxidant activity.

Fine atmospheric particles have physiological toxicity affecting human health. This study investigates the compositional and morphological properties of the particulate matter smaller than 10 mu m (PM10) collected from five different monitoring stations in Chelyabinsk, Russia. We used scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) for the investigation of PM10. In order to determine the possible sources of emissions of atmospheric particulate matter, a principal component analysis (PCA) was performed. The results revealed the presence of atmospheric PM10, such as aluminosilicates, calcium particles, sulfates, and metallic particles differentiated on the basis of the chemical composition and morphological parameters. Sulfate PM10 with metal inclusions contained Mn, Ti, Zn, Cu, and Cr. It obtained a higher content of potentially toxic elements in traffic-related S-rich particles compared with industrial-related PM10. It was the result of the solubilization of metals in airborne particles and increased toxicity. We obtained new coatings based on titanium nanooxide synthesized by the peroxy method for air purification from PM2.5 and PM10. They were macroporous and very effective means against industrial dust and PM air pollution.

In the present study the composite materials based on the Fe3O4/SiO2/TiO2 oxides, synthe-sized by the sol-gel method, were investigated. At the first stage, magnetite nanoparticles were precipitated by sodium hydroxide from a mixture of aqueous solutions of iron(II) and iron(III) sulfates under continuous ultrasonic treatment, after which they were washed with distilled water and dried under vacuum. At the second stage, the resulting magnetite particles were coated with silicon oxide according to the Stober method by dispersing them under the ultrasonic treatment in a solution of tetraethoxysilane in n-propanol, followed by hydrolysis of tetraethoxysilane in the presence of aqueous ammonia, washing and drying the obtained materials under vacuum. At the third stage, photocatalytically active particles based on titanium oxide were introduced into the composite by the solvent replacement procedure via dispersing the samples in an aqueous solution of peroxotitanic acid and adding n-propanol, stirring vigorously, followed by activation based on boiling in the water/ethanol (1:1) mixture, washing and drying under vacuum. The properties of samples influenced by the citrate stabilization and separation of magnetite particles at the stage of their synthesis into “light” and “heavy” magnetic fractions, as well as calcination of samples at 450 °C, were studied. The photocatalytic properties of the synthesized samples were studied during photodegradation of methyl orange, as well as their magnetic extraction from the suspension. The physicochemical characterization of the samples was performed using a high-resolution scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray powder diffraction, thermal analysis (TG–DSC), combined with mass spectrometry of gaseous thermolysis products. It has been found that the composites based on the mixed titanium-silicon oxide have a higher photocatalytic activity than the composites based on the pure titanium dioxide obtained via a similar procedure. The resulting photocatalysts can be used to purify water from dyes, followed by their extraction using a magnet.

For the first time, a simple and sensitive electrochemical sensor based on a screen printed electrode (SPE) modified with titanium dioxide (TiO2) and polytriazine imide submicrostructured composite (TiO2-PTI) has been developed for the simultaneous detection of fipronil (FIP) and its toxic metabolite fipronil sulfone (FIP-S). The submicrostructured composite material based on TiO2 and PTI was obtained by simple hydrothermal treatment of the Ti peroxocomplexes in the presence of pristine. This carbon nitride allotrope has better crystallinity and conductivity than its graphitic analog. It was found that the TiO2-PTI submicrostructured composite enhanced the electrochemical sensing of the SPE electrode towards FIP and its metabolite FIP-S in 0.1 M Britton-Robinson buffer (pH 10) at the oxidation potentials of 0.82 V and 0.94 V, respectively. In addition, it showed good stability and reproducibility for the determination of both analytes. Under optimal conditions, the peak currents by square wave voltammetry were found to vary linearly with FIP and FIP-S concentrations in the range from 0.01 to 10 mu M and from 10 to 50 mu M, with a detection limit of 8.42 nM, 3.6 mu g/kg for FIP and 9.72 nM, 4.04 mu g/kg for FIP-S. This sensor was successfully used to detect FIP and FIP-S in eggs and water samples with good recoveries of 90%- 106.6%.

In the present work the influence of duration of thermal treatment on the properties and photocatalytic performance of carbon nitride materials is investigated. Preparation of photocatalytic material proceeded in the eutectic molten salts KCl/LiCl mixture. This way of thermal treatment results in crystalline material with ordered structure, improved in comparison to convenient preparation methods. Duration was altered in range from 2 to 10 hours. Materials were studied by the methods of X-ray diffraction patterns, scanning electron microscopy. It was found that most ordered materials with the maximal degree of crystallinity are formed after 2–6 hours of high-temperature treatment. Elongation of thermal treatment up to 8 and 10 hours leads to less ordered material with the enhanced share o amorphous phase. Carbon nitride materials were used as photocatalysts for the selective oxidation of benzyl alcohol to benzaldehyde and demonstrate high selectivities to target product. 2 hours of thermal treatment leads to formation of photocatalyst with the highest conversion (79.2 %) and selectivity (92.4 %) values. Less effective material is formed after 10 hours of treatment, where selecivity level retained, while conversion drops to 48.6 %. Morphology of materials has maximal effect on the photocatalytic properties – high crystallinity is the main feature of catalytically effective materials.

Surface properties of the nanostructured materials are essential in attaining particular functionality, which is why there are a plethora of surface modification methods applied during or past the synthesis of nanoparticular substrates. Depending on the resulting content of the surface it could be heterophase forming modifications or pristine titania modifications. In this communication, we study a novel approach to pristine titania surface alteration by controlled chemisorption of the stable water-soluble titanium complex on the nanocrystalline anatase. Following on-air calcination for removal of organic residues converts chemisorbed complexes into oxide phase increments. Such an approach retains crystallinity and specific surface with simultaneous withdrawal of surface hydroxyl groups.

In the present work the influence of duration of thermal treatment on the properties and photocatalytic performance of carbon nitride materials is investigated. Preparation of photocatalytic material proceeded in the eutectic molten salts KCl/LiCl mixture. This way of thermal treatment results in crystalline material with ordered structure, improved in comparison to convenient preparation methods. Duration was altered in range from 2 to 10 hours. Materials were studied by the methods of X-ray diffraction patterns, scanning electron microscopy. It was found that most ordered materials with the maximal degree of crystallinity are formed after 2–6 hours of high-temperature treatment. Elongation of thermal treatment up to 8 and 10 hours leads to less ordered material with the enhanced share o amorphous phase. Carbon nitride materials were used as photocatalysts for the selective oxidation of benzyl alcohol to benzaldehyde and demonstrate high selectivities to target product. 2 hours of thermal treatment leads to formation of photocatalyst with the highest conversion (79.2 %) and selectivity (92.4 %) values. Less effective material is formed after 10 hours of treatment, where selecivity level retained, while conversion drops to 48.6 %. Morphology of materials has maximal effect on the photocatalytic properties – high crystallinity is the main feature of catalytically effective materials.

The effect of structure of 25 aromatic compounds on the morphology of carbon formed from them during heating to a temperature of 970°C in an inert atmosphere is studied. The specific surface area is determined for a number of products via nitrogen adsorption (28–48 m2/g). Several aromatic compounds are shown to form carbon without melting stage. X-ray phase analysis nevertheless confirms the formation of just amorphous carbon in all cases, and a negligible amount of graphite in amorphous carbon in only two cases. The thermolysis of a number of compounds is studied via synchronous thermal analysis. It is shown that slow heating during thermolysis can reduce the temperatures of transformation by tens of degrees and even alter the nature of thermolysis.

Considering the vast importance of peptide and protein interactions with inorganic surfaces, probing hydrogen bonding during their adsorption on metal oxide surfaces is a relevant task that could shed light on the essential features of their interplay. This work is devoted to studying the dipeptides' adsorption on anatase nanoparticles (ANs) in light and heavy water to reveal differences arising upon the change of the major hydrogen bonding carrier. Thermodynamic study of six native dipeptides' adsorption on ANs in both media shows a strong influence of the solvent on the Gibbs free energy and the effect of side-chain mobile protons on the entropy of the process. The adsorption is endothermic irrespective of the medium and is entropy-driven. Computer simulations of peptide adsorption in both media shows similarity in binding via an amino group and demonstrates structural features of protonated and deuterated peptides in obtained complexes. Calculated peptide- anatase nanoparticle (AN) descriptors indicate surface oxygens as points of peptide-nanoparticle contacts.