Abstract The kinetics of sorption and regeneration from industrial nitric acid–phosphoric acid solutions with the use of ion-exchange resins like KU-2 has been studied for both individual rare-earth elements (REEs) and their mixtures with the measurement of sorption and regeneration isotherms. The high rate of the mentioned processes enables the use of these resins in pulsed columns with a fluidized

Abstract The Henry constants upon the adsorption of inert gases with a natural isotopic composition (argon, krypton, and xenon) on activated carbon of the AG-3, VSK-5, SKT-3, and NWC 12x40 brands in a temperature range of 15–80°C are determined. A positive correlation of the Henry constants with the specific surface and micropore volume and surface normalized to the unit volume of the solid phase is

Abstract Decomposition NLP/LP/NLP methods are considered for the automated process design of the economically optimal distributed heat exchange networks between process streams using the assignment problem. The principle of fixation of intermediate variables and issues of the design of the superstructures of a heat exchange network and their decomposition are discussed. Methods to reduce the computational

Abstract This review is devoted to describing the main synthesis methods, the properties of MgO nanoparticles, and their areas of application, such as the creation of coatings for transformer and other types of steels, coatings on glass to control the energy of transmitted solar radiation, the creation of transparent and translucent one-component ceramics, the creation of multicomponent ceramic compositions

Abstract New methods for extracting cobalt and zinc ions from sulfuric acid solutions, of silver and lead ions from nitric acid solutions, and of copper ions from hydrochloric acid solutions with liquid membranes based on di(2-ethylhexyl)phosphoric acid under conditions of galvanostatic electrodialysis with cathodic electrodeposition of metals are presented. Almost complete (93–100%) extraction from

Abstract The results of an analysis of mathematical models for a continuous fermentation process for lactic acid production have been presented. Mathematical models are represented by equations with the kinetics of the formation of lactic acid for strains of the following types: strains that consume only the main substrate (most frequently, glucose) and do not form by-products; strains that form by-products;

Abstract The results of an analysis for ginsenosides in the Multiphytoadaptogene (MPA) phytoadaptogene composition with antitumor properties by high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) are presented. Ginsenosides are identified with the use of commercial standards of ginsenosides and some literature data. Ginsenosides Rb1, Rb2, Rc, Rd, Rg1, Rg2, Re, Rf, and

Abstract Taylor–Couette flow between independently rotating cylinders with a relatively small aspect ratio Γ = 2.4 has been investigated numerically. The Navier–Stokes equations with the uncoupled convection-diffusion-reaction equation are solved using a spectral development in one direction combined together with a finite element discretization in the two remaining directions. The study includes the

Abstract An improved approach to determining the kinetic characteristics of electrochemical pressure-driven membrane separation of solutions has been proposed. It is based on the Spiegler friction theory and takes into account the combination of the effects of chemical and electrochemical potentials. The numerical values of the coefficients of friction fωm, f+m, and f+ω in the solvent–membrane, solute

Abstract The efficiency of polyethylene glycol methyl ether 350 (PEG ME-350) in the process of extracting thiophene from model motor fuel has been studied experimentally. The influence of the contact time of the phases, the composition of the extractant, the initial concentration of thiophene, and the volume ratio of the extractant and model fuel on the extraction of thiophene has been investigated

Abstract A method is described to solve the inverse problem of chemical kinetics (estimation of the rate constants for elementary steps of chemical reactions) from the data of nonstationary experiments in an open isothermal plug-flow reactor without using optimization algorithms. This method is used to determine the rate constants for elementary steps and the intervals of their values for reactions

Abstract The importance of aqueous two-phase systems has been increased recently as a method with greater performance capability in separation and purification of biological products along with economic and operational advantages compared to the conventional methods. However, the thermodynamic modeling of some of applicable aqueous two-phase systems like tetrahydrofuran + polyols has not yet developed

Abstract A method is proposed and multifactorial experiments are carried out to determine the effectiveness of various compositions of chemical additives for intensifying the processes of phytoextraction of mercury and other heavy metals from soils. White creeping clover (lat. Trifolium repens L.) is used as the object of experiment. As a result of a systematic analysis of the results of experiments

Abstract The problem of tritiated wastewater treatment is a pressing challenge in many countries. The principal man-made sources of tritium are nowadays represented by nuclear reactors of different applications, as well as plants for processing spent nuclear fuel. This article presents a review of literature data dedicated to the problems of formation of tritium in nuclear energy installations of various

Abstract The possibility of preparing a variety of fertilizers from Lao Cai apatite raw material with various contents of a water-soluble form of phosphorus at a nearly identical fraction of total and assimilable phosphates is shown.

Abstract The effect of climatic factors is studied on the properties of basalt and glass textolite prepared by the infusion method by the sequential laying of the reinforcing material on the mold, impregnation with a three-component epoxy binder consisting of ED-22 epoxy resin, Iso-MTHFA (isomethyltetrahydrophthalic anhydride) hardener, Agidol 53, an accelerator for the hardening of epoxy compositions

Abstract The modification of functional materials with rare-earth elements (REEs) for different purposes by the low-temperature extraction–pyrolysis method has been carried out. Luminophors and magnetic and biomedical materials have been synthesized, and their compositions and properties have been studied. It has been established that the introduction of modifying additives (REE ions) could significantly

Abstract Using chemical and XRD phase analysis, along with electron microscopy, the hydrolytic processing of metallic bismuth into high-purity citrate has been studied. A comparison of two synthesis methods is carried out for bismuth(III) citrate of BiC6H5O7 composition by precipitation from technological nitric acid solutions by the addition of a citric acid solution and by the reactions of solid

Abstract The possibility of removing U(VI) from aqueous solutions using layered double hydroxides of Mg and Al, which contain β-cyclodextrin (LDH-Mg-Al-CD), has been studied. It is found that LDH-Mg-Al-CD does not sorb [UO2(CO3)3]–4 (the sorption degree does not exceed 0.001% after 24-h contact between the solid and liquid phases). At the same time, it is established that the application of LDH-Mg-Al-CD

Abstract A method for producing lanthanum–cerium phosphates activated by terbium of the compositions La0.8Ce0.15Tb0.05PO4 and La0.8Ce0.15Tb0.05(PO3)3 has been suggested. The main advantage of this method in comparison with those that are already known is a decrease in temperature and process time. Luminophores demonstrated an intensive green luminescence in the range 450–620 nm. It has been determined

Abstract Phase equilibria in the sections of the Ca(NO3)2–CO(NH2)2–H2O system and the deicing properties of calcium nitrate and carbamide mixtures with a ratio between the components ranging from 90 : 10 to 40 : 60 have been studied. Eutectic temperatures with ice, melting ability at a temperature of –5 and ‒10°C, and the character of interaction with water (the occurrence of an endothermic or exothermic

Abstract Phase equilibria have been studied in the sections of the NaCl–CaCl2–H2O and NaCl–CaCl2–NaHCOO–H2O systems at different concentration ratios between the salts at temperatures below 0°C. The effect of sodium formate on the deicing properties of sodium and calcium chloride compositions is considered.

Abstract Results of an experimental study on a semibatch multistage chromatographic extraction process for the separation of a binary mixture of components in a multistage setup with eluent recycling under different mixture-loading conditions are presented.

Abstract Computational studies of the separation processes of mixtures of three, four, and six components using the example of lanthanides have shown that, using recirculation–countercurrent chromatography, it is possible to separate complex mixtures of metals with different distribution coefficients with the simultaneous production of concentrated fractions of metals.

Abstract The processes of converting propane-butane and propane-propylene fractions into aromatic hydrocarbons on zeolite catalysts modified by the introduction of Zn, La, Fe, Co, and phosphorus has been investigated. The behavior of catalysts in the processing of light hydrocarbons depends on the structure and state of active centers. Physicochemical characteristics of the developed catalysts have

Abstract Sulfur compounds are found in crude benzene from coke production. One of these compounds is thiophene. Extractive distillation (ED) with dimethylformamide as a separating agent can be used to remove it from crude benzene. The relative volatility in the benzene–thiophene binary system increases in the presence of dimethylformamide from 1.13 to 1.46–2.18. The purpose of this work is to study

Abstract A method for producing metamaterial cross-linked polyvinyl alcohol–magnetite nanoparticles based on the chemical deposition of Fe3O4 ions with NH3 solution into the volume of polymer granules is considered. The granules of the metamaterial are used as a sensor element for determining the composition of solutions by optical micrometry: the kinetic dependences of the swelling of the granules

Abstract The scientific and technical problem of calculating the transfer of momentum, heat and mass of water vapor in cooling towers has been solved theoretically using a turbulent boundary layer model in the gas phase for irrigated packing blocks. A dissipative mathematical model for determining the average tangential friction stress at the gas–liquid interface in film contact devices (sprinkler

Abstract Dueck’s mathematical model of biofilm is discussed. This model is also generalized to cover all substratum types. This system is based on a nonlinear reaction–diffusion equation that includes a nonlinear term related to square law of microbial death rate. In this paper, the analytical expression of the substrate consumption and flux in a biofilm is obtained by solving the nonlinear differential

Abstract A mathematical model of the processes of heat and mass transfer during the convective drying of a colloidal capillary-porous material, taking into account the phenomenon of shrinkage, is presented. This model is formulated in an area with a movable boundary. The mass conductivity equation includes a convective term to describe the additional internal mass transfer of the material by the matrix

Abstract A statistical model of porosity formation during climatic tests of a composite material with basalt reinforcing fibers is proposed based on an analysis of experimental data.

Abstract The spontaneous precipitation of caffeine from black coffee bean extracts obtained by extraction with supercritical carbon dioxide has been found. This effect is observed for various types of coffee when using pressure values of the supercritical extractant on the order of 40–50 MPa. Two valuable products, caffeine and decaffeinated coffee oil, can be obtained by the simple centrifugation

Abstract The results of an experimental study and numerical modeling of the distribution of the gas velocity and pressure in tangential swirlers are presented. The modeling is executed by the finite element method using the k–ε turbulence model in the Comsol Multiphysics program. The resistance coefficient of tangential devices at different design parameters of the swirler is experimentally determined

Abstract Analytical solutions of the non-steady-state Brinkman equation that describes the flow of a fluid inside a porous spherical shell with a solid impermeable core immersed into it, which makes translational oscillatory motions, and of the Navier–Stokes equation in the Stokes approximation outside the shell are obtained. The fields of the filtration rates in the porous medium and velocities of

Abstract The change in the viscosity of a reaction mixture in the process of polystyrene synthesis and the possibility of controlling it in the course of polymerization have been studied. A laboratory reactor is used in this study, and the plots meeting our expectations are obtained for the change in the reactor stirrer rotation speed and output adjustable speed drive signal. An adequate fuzzy viscosity

Abstract A photoactive р-Si/p-Cu2O/n-ITO heterostructure synthesized via the pyrolytic-extraction deposition of copper oxide and indium–tin oxide onto a silicon substrate is presented. This method is demonstrated to provide the formation of an electron-hole p-Cu2O/n-ITO junction, thus opening up opportunities for the creation of heterostructural solar cells on large surfaces at decreased expenditures

Abstract A choline chloride–sulfosalicylic acid deep eutectic solvent (DES) is proposed for dissolving the oxides Co(II), Cu(II), Zn(II), Fe(III), Ni(III) and Mn(III). An experimental study of the influence of the dissolution time, solid : liquid mass ratio, temperature, and molar ratio of choline chloride and sulfosalicylic acid on the dissolution of metal oxides in the proposed DES has been carried

Abstract We studied the possibility of using a modified cascade of mixing and settling centrifugal extractors as a device for carrying out liquid–liquid chromatography processes. Based on the results, it is concluded that the cascade can operate in the chromatography mode with relatively small changes in the piping system of the apparatus.

Abstract The dissolution of concentrated ozone in water at liquid and gas counter-flows has been studied. It was shown that the ozone flow rate can be increased from 0.042 cm3/s cm2 (flotation treatment of water with ozone) to 3.6 cm3/s cm2 (counter-flow). A scheme of counter-mixing of ozone in gas with water without using flotation technology was suggested. The optimum ratio of ozone carrier gas to

Abstract A new approach is proposed to increase the recovery of Ni and Cu from the fly ash formed by roasting the copper–nickel matte in the production of nickel at PAO MMC Norilsk Nickel. This approach is based on the gas-phase treatment of fly ash in the HNO3(vapor)–air or NOx–H2O(vapor)–air atmosphere with subsequent leaching of Ni and Cu with water. It is shown that nitrating media efficiently

Abstract A mathematical model was presented to describe the injection of “warm” carbon dioxide into a porous geological formation that is initially saturated with methane and its hydrate with a negative (below the melting point of ice) temperature. A scheme in which three regions emerge in the formation was considered: a near region, which contains carbon dioxide and its gas hydrate; an intermediate

Abstract A new technology has been considered to process monazite concentrate by treating it by a phosphoric acid solution in the presence of strong acid cation exchange resin. The end products are a carbonate of hydroxide concentrate of rare-earth elements (REEs), orthophosphoric acid, and thorium concentrate.

Abstract A brief review of studies of the extraction-pyrolytic method to produce inorganic materials of various purposes is presented. The potential to use products of the extraction-pyrolytic method as precursors in additive manufacturing is discussed. Modern methods of 3D printing using powder materials are considered. A process flow diagram is proposed for an extraction-additive technology (from

Abstract Lanthanum extraction from chloride-acetate solutions using mixtures of bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) and caprylic acid in hexane has been studied depending on the composition of aqueous and organic phases. Based on the results, it is found that the lanthanum extraction from chloride-acetate solutions proceeds according to a cation-exchange mechanism occurring in the

Abstract A systematic analysis of the mercury content in various subsystems of the environment of the Crimean Peninsula has been carried out which includes (1) an assessment of the presence of natural geochemical and anthropogenic sources of mercury input into the subsystems of the Crimean environment, (2) an assessment of the load on the territory of the peninsula with mercury-containing waste according

Abstract The fluorination of elementary substances and inorganic and organic compounds with elementary fluorine is accompanied by high heat release (of about hundreds of kilojoules per mol of fluorine), which determines the high probability of their implementation in the unsteady-state temperature mode (combustion or thermal explosion mode) when the temperature of the process products is close to adiabatic

Abstract The features of distribution are studied and a complex technology for the separation of samarium, europium, and gadolinium is proposed. This technology involves the initial isolation of 70–80% of the europium concentrate by extraction with organophosphorus acids, which makes it relatively easy to obtain pure compounds of samarium and gadolinium in subsequent operations. At the last stage,

Abstract A complex for processing liquid radioactive waste from Mayak chemical metallurgical production plant has been designed, constructed, and put in operation. Pilot trials were performed to test the technology for processing liquid low-level radioactive waste using cross-flow ultrafiltration. The method was found to be efficient. A total of 126 000 m3 of solutions were processed during the trials

Abstract Issues of the formation of dust particles in high-temperature technological reactors are considered with an emphasis on the processes occurring in electrothermal ore-reduction furnaces of phosphorus production, when dust serves as a source of sludge that contaminates the product. A model of dust formation is proposed based on the hydrodynamic interaction of gas bubbles with liquid when they

Abstract Physical and mathematical simulation of the process of adsorption of gas components on the adsorbent injected into the steam-air flow in a cylindrical tube and Venturi tube was carried out. Calculated estimates of CO2 adsorption on aluminosilicate with a mass median particle size of 50 µm were carried out using the phase equilibrium coefficient found by the authors in [1] by comparing the

Abstract Results of experimental studies on the purification of a lithium chloride solution from soluble chemical impurities by dynamic sorption are presented. Chelate cationites Axionit 3S and Lewatit MonoPlus TP-260 in the Н+ and \({\text{NH}}_{4}^{ + }\) forms were used as sorbents. The mass content of lithium and impurities in the initial solution, eluates, and desorbate and the factors of lithium

Abstract A ceramic material from over 800 years ago has been studied. Ceramic manufacturing processes are classified among inorganic chemical technologies. The problems of ensuring the durability of buildings and reducing the cost of repairs are extremely relevant and due to the amount of industrial, residential, and individual construction. The elemental chemical composition of the material shows

Abstract A model and description of the monolithic structure of reinforced plastics in one direction (1D structure) in new generalized and reduced parameters (Θ, Θ/В, and Θ/Sf), which allow one to consider structure formation from the perspective of, on the one hand, the reinforcing fiber, taking into account its dimensions, packing, surface area, and content, and, on the other hand, the polymer matrix

Abstract The history of the formation and development of a new field of research in chemical technology, such as the theory of chemical process systems engineering, including methods for the analysis, optimization, and synthesis of chemical process systems (CPSs), is briefly surveyed. A classification of the modern engineering main types is given. Methods and techniques for chemical processes (CPs)

Abstract The mechanism of a heterogeneous reaction that occurs during the bubbling of gas bubbles released during the reaction has been investigated. Theoretical provisions on the formation of gas bubbles in a heterogeneous solid–liquid–gas reaction based on the formation of a moving microlayer of a liquid reagent under a gas bubble are considered. Analogously with boiling, a hydrodynamic model of

Abstract At the pilot plant, the main parameters of the electromembrane process of extracting cadmium ions from a sulphate-ammonium cadmium electrolyte with high performance characteristics and a bath for rinsing cadmium parts in stagnant water (collection baths) have been determined. It is shown that the degree of extraction under stationary conditions is about 99%, which corresponds to the values

Abstract Moderate hydrate forming conditions of tetra-n-butylammonium salts have made these compounds as attractive materials to store the cold in air conditioning systems. In this research, the rate of methane hydrate formation in presence of a thermodynamic additive, tetra-n-butylammonium chloride (TBAC), and a surfactant, Polysorbate 80, is studied. The tests were carried out in a 169 cm3 stirred

Abstract The current research work elucidates an experimental study on the stability performance of a green emulsion liquid membrane (GELM). A GELM based on rice bran oil (RBO) is a new subset of a previously existing organic solvent-based emulsion liquid membrane (ELM). These organic solvents are responsible for several environmental as well as for economic problems. A GELM is an economical and environmentally

Abstract The possibility of chemical encapsulation of surfaces of technological equipment made of PVC materials into porous H+- or OH–-conducting and hydrogen- or oxygen-producing layers. They consist of activated carbon grafted with ethanolamine derivatives of PVC and aqua complexes H2SO4, NaOH, or KOH and are bridges between electrolyte solutions in reactive electrochemical matrices. With cathodic

Abstract The results of studying the physical properties of a deep eutectic solvent based on choline chloride and sulfosalicylic acid have been presented. A phase diagram for this two-component mixture has been constructed, and the dependences of its density and refractive index on temperature have been studied for the first time. The molar refractivity of the deep eutectic solvent under study has