The results of extractive distillation of a four-component mixture of solvents are predicted by means of simulation using the Aspen Plus 10.0 software. Schematic flow diagrams of separation are suggested using various selective agents in distillation columns operating under different pressures.
The structural and energy characteristics of some commercial and laboratory microporous carbon adsorbents applied in the cyanide gold recovery technology are studied. The average effective widths of the micropores in these adsorbents are close to 1.1 nm. The successive application of such adsorbents is explained by molecular sieve effects with respect to the cyanide gold complex.
The paper studied the extraction of lanthanides from nitrate solutions (0.01 M HNO3 + 0.1 M NaNO3) in hexane–isopropanol–water three-component systems using Cyanex 572 as an extractant. The experiments showed the promise of using the extractant Cyanex 572 for the separation of lanthanides from nitrate media in three-component systems.
Laboratory samples of a new functional material are obtained by mixing two fractions of crushed gabbro rock with different particle sizes in the ratio coarse : fine = 1 : 10 and discrete basalt fibers in an amount of 8 wt % of the initial mass of the mixture. Potassium liquid glass is used as a binder. The resulting mass is placed in a mold, followed by pressing and molding of blanks. After drying, they are sintered. The sintered samples have the shape of a cylinder with dimensions h × d = 10 × 10 mm. For all samples, the following are determined: pycnometric density, Brinell hardness, tensile strength, and residual deformation.
An assessment is made of the current state of the global food security, which arises as a result of new challenges, in order to achieve the UN Sustainable Development Goals. Currently, aquaponic technologies are considered quite promising for providing regional consumers with food (hydrobionts and phytoproducts). Reagent-free technologies for intensifying plant growth and development (electromagnetic influence, ultrasonic waves, corona discharge) are analyzed. The use of installations for the electrolysis treatment of aqueous solutions for growing hydrobionts before feeding them into hydroponic modules is substantiated. The results indicate a significant increase in plant productivity by more than 30% after electrochemical treatment. Changes in the hydrochemical and hydrophysical properties of water after electrolysis are analyzed. A scheme of an aquaponic system for intensifying reagent-free electrolysis of growing microgreen plants is proposed and verified. It is substantiated that further research should be aimed at building process-control systems in aquaponic installations and creating specialized energy-efficient DC power supplies.
The general conditions of the synthesis of luminophores based on mixed oxides of rare-earth and rare elements by a low-temperature extractive–pyrolytic method are discussed. The dependence of the relative integral intensity of luminescence on the pyrolysis temperature of the precursors is studied on the example of samples of luminophores based on oxides of europium Eu2O3 and terbium Tb4O7; europium, terbium, yttrium, and praseodymium oxysulfides; europium phosphates Eu3PO7 and Eu(PO3)3 and phosphate Eu(PO3)3:Eu2+ doped with a Eu2+ ion; terbium phosphates TbPO4 and Tb(PO3)3; mixed phosphates La0.8Ce0.15Tb0.05PO4 and La0.8Ce0.15Tb0.05(PO3)3; europium polyniobates EuNb3O9 and EuNb5O14; europium polytantalates EuTa3O9, EuTa5O14, and EuTa7O19; terbium polytantalates TbTa3O9, TbTa5O14, and TbTa7O19; and europium ortho- and metaborates La0.95Eu0.05BO3 and La0.95Eu0.05(BO2)3 including La0.03Eu0.05Bi0.05BO3 and La0.90Eu0.05Bi0.05(BO2)3 doped with bismuth ions. It is found that, according to the data of X-ray diffraction, individual compounds are formed at temperatures as low as 600°C. Increasing the pyrolysis temperature of the precursors to the optimum temperature leads to a gradual growth in the relative integral intensity of the bands in the luminescence spectra. The luminescence spectra of the samples of luminophores based on compounds of europium or terbium consist of a series of bands corresponding to the 5D0–7Fj transitions between the multiplets (j = 0, 1, 2, 3, 4) characteristic of the Eu3+ ion (in the region of 550–750 nm) or 5D4–7Fj transitions (j = 1–6) characteristic of the Tb3+ ion (in the region of 500–650 nm), respectively.
Abtract—The possibility was shown of using a thin-film rotary apparatus for the preparation of dry precursor salts in the form of ammonium uranyl nitrate and uranyl formate containing up to 5 wt % low-background plutonium. Dioxide powders obtained after the thermal decomposition and reduction of the salts are represented by a solid solution (U0.95Pu0.05)O2 in both cases. Based on the analysis of the amounts of secondary radioactive waste (RAW), specific surface areas of powders, and particle shapes, it was decided to continue elaboration of the process using highly active uranium-plutonium solutions and formic acid.
A comparative analysis was made of the effect of high-density polyethylene (HDPE) and ultra-high-molecular-weight polyethylene (UHMWPE) on the vulcanization characteristics of rubber mixtures and the physicomechanical properties of vulcanizates based on BNKS-18AMN nitrile butadiene rubber. It was shown that the introduction of 10 pts wt HDPE has a reinforcing effect, but reduces the degree of crosslinking of vulcanizates and abrasion resistance. In comparison with HDPE, the introduction of 10 pts wt UHMWPE does not have a reinforcing effect, but on the contrary leads to a decrease in physicomechanical properties in tension, but at the same time increases the wear resistance and frost resistance of the samples.
Abstract—Information is provided on the synthesis of mono-azo compounds with 60–97% yields by the azo coupling reaction of 2-methylresorcinol with aryldiazonium salts of various structures. The synthesized mono-azo compounds are tested as acid and disperse dyes for dyeing of textile materials made of polycaproamide fibers. The results of research of color fastness to washing, sweat, and light show good operational properties of coloring. Conclusions on the dependence of color fastness on the structure of the studied azo compounds are made.
The effect of Tb3+ and Bi3+ sensitizing ions on the spectral luminescent characteristics of the Eu3+ activating ion in lanthanum ortho- and metaborates is studied. The compounds are studied by X-ray diffraction and luminescent spectroscopy. The doping of La1 – xEuхBO3 and La1 – xEuх(BO2)3 (х = 0.025; 0.05; 0.075; 0.10) with ions Tb3+ and Tb3+ in combination with Bi3 is found to enlarge the range of luminescence in the visible region. Moreover, due to energy transfer from Bi3+ to Eu3+ in lanthanum orthoborates, the integral luminescence intensity (λex ~ 615 nm) grows by ~25% as compared to the samples free from Bi3+ (optimal Bi3+ concentration is 5 mol %).
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