Russian Journal of Applied Chemistry最新文献

The necessity of global market shift for production of light olefins influenced the catalytic cracking process in the direction of process optimization and construction modernization. This work investigated the influence of configuration (distribution) of feedstock injection nozzles on the hydrodynamic regime and performance of the riser-reactor for production of light gases (C₁–C₄). We considered eight feedstock injection nozzles in two cases. In case (a), eight nozzles are distributed in one plane around the riser-reactor, while in case (b), eight nozzles are distributed in two planes (four nozzles on each plane). Computational fluid dynamic modeling with four-lump reaction scheme with consideration of coke formation was used. Applied kinetic parameters were determined for an industrial riser-reactor with microspherical zeolite-containing catalyst. It was achieved that the distribution of solid-gas phases was enhanced for geometry (b). Mass fraction of light gases was obtained up to 0.5 (50 wt %). Moreover, the formation of coke was up to 14–15 and 9–10 wt % for geometry (a) and (b), respectively. It was observed that the main zone of chemical reactions is up to 10–15 m above the feedstock injection zone. Therefore, shortening the riser-reactor is recommended.

Rechargeable magnesium batteries (RMBs) have attracted attention as next-generation energy storage systems due to their high safety, large volumetric capacity, low redox potential of magnesium anode, and cost effectiveness. However, the development of highly reversible cathode materials for RMBs with fast intercalation kinetics is very challenging due to the slow diffusion of Mg²⁺ ions and the low reversible capacity, characteristic of divalent magnesium ions in the cathode material. This is a consequence of the strong electrostatic interaction between the Mg²⁺ ions and the cathode material, which makes the reversible intercalation difficult. In this work, a cathode material based on aluminum-doped vanadium oxide with an expanded interlayer space was synthesized. The structure of the material was studied by high-resolution X-ray diffraction. Its electrochemical properties in propylene carbonate magnesium-containing electrolytes have been studied by cyclic voltammetry. The initial values of the specific capacity of the Al_xV₂O₅ cathode of about 136 mAh g^–1 at a scan rate of 0.4 mV s^–1 were obtained from the CVs by integrating the current under the cathodic curve. The analysis of chemical composition of the Al_xV₂O₅ cathode after the discharge cycle showed a significant amount of intercalated magnesium ions.

This work aims at the exploitation of huge quantities of iron scrap wasted during iron production via recycling iron wastes using an electric arc furnace as a partial replacement to ordinary Portland cement to increase the production capacity of Portland cement without further firing and hence decreasing the ecological problems associated with its production. Six mixes were prepared with different additives of iron scrap wastes up to 50 wt. % on the expense of the cement content. Physico-mechanical properties namely water of consistency, setting time, hydration behavior, sintering parameters (bulk density and apparent porosity) as well as mechanical properties (cold crushing strength) were tested according to the International Standard Specifications. X-ray diffraction technique was used to investigate the phase compositions of the hydrated cement samples. The results indicated a marked improvement in the physicomechanical properties of the prepared cement mixes as the content of iron scrap waste additives increased. The mix composed of 70 wt. % Portland cement with 30 % iron scrap waste additive was considered as the optimum mix due to its outstanding physical and cementing properties (setting time; initial:48 min., final: 160 min., combined water; 43.25 %, bulk density; 3.22 g/cm³, apparent porosity; 10.46 %, cold crushing strength; 530 kg/cm²) which satisfy the requirement of International standard of mixed cement.

The Phycoerythrin-Nitrocellulose test paper (PNTP) for the content of copper ions in water is prepared by loading the Phycoerythrin on activating nitrocellulose membrane, which can be used on the test of wastewater. Its detection ability is explored under different pH values and various additional metal ions through the colorimetry. The optimal conditions of PNTP preparation have been determined to be the material/liquid ratio of 1 : 1 and PE concentration of 0.04 mg/mL, respectively. Meanwhile, its specificity for detection copper ions has been proved by our experiments. Our experimental results show that the detection accuracy of copper ions reaches 10 mg/L at pH 3 and 4, 0.01 mg/L at pH 5 and 7, and 0.1 mg/L at pH 6 and 8. This meets the requirements of most water quality monitoring and is suitable for on- site rapid detection of copper ion concentration in water.

Activated carbons (AC) have been effectively produced from rice husk using the following activation methods: i) physical activation; ii) chemical activation. We prepared ACs using CO₂ gas as an activator under various activation temperatures for a time period of 1 hour. This study investigated the fabrication of activated carbon (AC) from rice husk using a chemical activation method that used H₃PO₄, KOH, and ZnCl₂. This study looked at how to make activated carbon (AC) from rice husk utilizing a chemical activation technique that included H₃PO₄, KOH, and ZnCl₂.The influence of several parameters, for instance carbonization temperature, carbonization duration and concentrations, on ACs BET surface area was investigated. Rice husk activated carbons (RHAC) were described by thermo-gravimetric investigation (TGA), Scanning Electron microscopy (SEM), Brunauer Emmett Teller (BET) surface and N₂ adsorption. Both techniques of activating activated carbon have high adsorption characteristics. During this, adsorption parameters for utilizing the GC-MS method to analyze gasoline. The agricultural wastes employed in the study have been demonstrated to be possible precursors for the cost-effective on-site generation of activated carbon, thereby easing the problem of agricultural waste management.

The main regularities of electrochemical transformations of lithium octasulfide in a 1 M LiN(CF₃SO₂)₂ solution in sulfolane on the surface of carbon nanomaterials synthesized by low-temperature pyrolysis of ethanol vapors in an argon atmosphere on aluminum foil in the presence of a nickel catalyst were studied. It was found that the depth of electrochemical transformations of sulfur and long-chain lithium polysulfides on the surface of the synthesized carbon nanomaterials is close to 100%. The carbon materials were characterized by Raman spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The Raman spectra of the synthesized carbon materials show characteristic D and G bands with maxima at 1323 and 1589 cm^–1, respectively. The D/G intensity ratio is 0.7, indicating a significant proportion of sp³-hybridized carbon atoms. SEM micrographs reveal carbon fibrous structures with diameters of 25–35 nm. The synthesized carbon nanomaterials contain (%): carbon 96, oxygen 2.8, iron 0.3, and nickel 0.9.

Iron(III) methacrylate was synthesized and characterized by elemental analysis and IR spectroscopy. The mechanism of thermal decomposition of iron(III) methacrylate was studied using differential scanning calorimetry combined with a mass spectrometer in a nitrogen environment. Experimental and statistical mathematical models of the thermolysis of iron(III) methacrylate were obtained, relating a number of response functions (carbon and hydrogen concentrations in the nanocomposite, content of hematite phases, α-Fe, average diameter of nanoparticles (according to X-ray diffraction data), saturation magnetization, residual magnetization, coercivity) with temperature and time of the thermolysis process. Response surfaces were constructed to illustrate the dependence of the listed response functions on temperature and time of thermolysis. As a result of the analysis of the obtained response surfaces, the conditions for the synthesis of a nanocomposite with specified characteristics, in particular with a higher content of the ferromagnetic α-Fe phase, were determined.

In this work, Ni/Ga₂O₃ catalysts were prepared via the cold plasma method. The Ni/Ga₂O₃ composite treated with plasma exhibited superior performance, achieving a CO₂ conversion of 13.8% and a methanol selectivity of 56% at 300°C and 5 MPa. These values were notably greater than those obtained with catalysts prepared through calcination or chemical reduction. Compared with the calcination method, cold plasma treatment results in smaller particle sizes (4.12 nm) because of the low temperature of the plasma, which increases the number of active sites. Additionally, high-energy electron bombardment within the plasma field strengthens the interaction between Ni and the Ga₂O₃ support. This enhanced metal‒support interaction, which is stronger than that achieved via calcination or chemical reduction, plays a critical role in improving the catalytic activity for the CO₂ hydrogenation reaction. The intricate mechanism of CO₂ hydrogenation on the Ni/Ga₂O₃-plasma-H₂ catalyst was elucidated via a combination of advanced characterization techniques and in situ DRIFTS analysis. Hydrogen dissociates on Ni nanoparticles and subsequently spills over onto the Ga₂O₃ support, whereas oxygen vacancies promote CO₂ adsorption, resulting in the formation of bidentate carbonate species as key intermediates. These intermediates are then hydrogenated to produce methanol.