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2023

Archives Journal Chemical Bulletin Vol. 6

Analysis of the effect of technological parameters on desulfurization of agglomeration charges

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 5-17 p.
Abstract
This paper presents an analysis of the influence of technological parameters such as temperature, basicity and carbon content on the degree of desulfuration (removal of sulfur) during agglomeration of iron ore raw materials, which in the future will help to detect and calculate the most effective mode of operation of firing conveyor and sintering machines during heat treatment and processing of mineral iron ore raw materials. It was found that the most significant effect on the desulfurization of fluxed sulfate-containing charges is to reduce the size of the ore and the introduction of fusible additives that reduce the viscosity of the slag. It was revealed that the effect of the first factor is limited by the capabilities of crushing departments of mining and processing plants and the difficulties of sintering fine-grained charges, and a decrease in the fusibility of the sintering charge can lead to a deterioration of combustion processes and a drop in the technical and economic indicators of the sintering process. Gorenje It was found that the implementation of additional measures to obtain low-sulfur agglomerate from sulfate-containing ores is hampered by the lack of research on the kinetics of the main reactions that determine the final sulfur content in the agglomerate. It has been shown that dissociation of calcium and barium sulfates in contact with silicon, iron and aluminum oxides is possible at temperatures of 1000-1100°C. It was found that the dissociation of sulfates proceeds at a rate that ensures an increase in the degree of desulfuration. A decrease in the degree of desulfurization is observed in the temperature range of1200-1300°C, due to liquid-phase contact with silicon, iron and aluminum oxides. It was found that further studies of the kinetics of thermally activated reactions of high-temperature dissociation of barite and calcium sulfate under conditions close to agglomeration processes in operating heat treatment units of iron ore raw materials are necessary to increase the degree of desulfuration of sulfate-containing fluxed agglomeration charges.
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The impact of environmental problems on epidemiological aspects and human health because of human industrial activity

 18-26 p.
Abstract
Industry is one of the main directions of economic development not only in the Russian Federation, but also in other developed countries of the modern world. Industry contributes to the acceleration of scientific and technological progress and the pace of economic development, improving the level of well-being of the population. Despite a number of objective advantages observed with the intensive development of industry, many problems caused because of industrial activity of a person. One of the most urgent problems of the subject area under con-sideration is environmental pollution and its negative impact on epidemiology and human health. The main pur-pose of the presented article is to complete an analysis regarding the impact of human industrial activity on epide-miological aspects and human health. Because of the work, the main factors that negatively affect the environmen-tal situation, as well as the relevance and necessity of reducing this influence in order to improve the epidemiologi-cal situation and human health, examined. Based on the considered factors, the author's approaches to ensuring environmental safety in the operation of industrial enterprises are formed. The practical value of the presented work consists in the possibility of applying such approaches in establishing a safe from the point of view of the eco-logical situation of the functioning of industrial enterprises.
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Surface-active and micelle-forming properties of binary mixtures of glycyrrhizin and decyl glycoside and stabilization of foam stabilized by such a mixture with xanthan and keratin additives

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 27-42 p.
Abstract
The surface and micelle-forming properties of two surface-active sugar derivatives and their binary mixtures were studied: dipotassium glycyrrhizinate, which is an anionic surfactant of natural origin (saponin) and has biologically active properties, and a nonionic sugar surfactant decyl glycoside. Decyl glycoside has a noticeably higher surface activity and a noticeably lower CMC value than dipotassium glycyrrhizinate. Using Rubin's equations, the composition of mixed micelles and the parameters of surfactant interaction in them were calculated. It has been shown that a synergistic effect is observed in aqueous solutions of binary mixtures of these surfactants. Due to this, dipotassium glycyrrhizinate can be used together with decyl glycoside as a base for foaming solutions for cosmetic, pharmaceutical and medical foams. Using dispersion analysis of foam over time, the stability of foam stabilized with a mixture of dipotassium glycyrrhizinate and decyl glycoside in a molar ratio of 0.2:0.8 and the ef-fect on the stability of foam of the addition of two different biopolymers: polysaccharide - xanthan (xanthan gum) and protein - keratin of sheep wool hydrolyzate were studied. Based on dispersion analysis of foam micrographs, it was shown that both polymers increase the durability of the foam over time. Foam containing xanthan breaks down primarily through Ostwald ripening rather than coalescence. Foam with keratin hydrolyzate has a lower initial dispersion and number of bubbles than foam with keratin hydrolyzate. The stability of both foams is close, but slightly higher in the case of the addition of keratin.
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A method for producing high-purity carbon material from plant waste

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 43-53 p.
Abstract
Сarbon materials are widely in demand, used in many sectors of human life. Due to their complex properties, they are indispensable both in industry or agriculture, and in environmental protection. However, the ecological and economic aspects of their production: the availability of primary raw materials and the cost of obtaining high-quality adsorbents sharply increase the cost of these products. On the other hand, a lot of plant waste is generated annually, estimated in Russia at several million tons. Organic fractions of municipal waste represent potential raw materials for thermal processing into carbon materials. This direction of their utilization allows us to solve two tasks at once – to obtain inexpensive high-quality carbon material and reduce the amount of waste of plant origin. In this work, the object of research was pre-dried rose flowers, which were crushed, heat treated at 450-500 °C for 4 hours, followed by multistage washing with hydrochloric and hydrofluoric acids and water. It is shown that the chemical purity of the product depends on the sequence and number of washing steps. The resulting carbonizate was characterized by relative purity (ash content 0.9 wt. %. with a carbon content of 84%) and satisfactory porosity, which, according to the test results for test substances – iodine and methylene blue (adsorption capacity for which is 35.5% and 45 mg·g–1, respectively), considered this material promising in wastewater treatment water treatment and other fields. For comparison, the article presents the quality indicators of activated carbon from birch wood of the BAU brand and a number of agricultural waste.
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Investigation of the features of sunflower oil emulsions and the effect of the emulsifier on the efficiency of sorption purification

 5-13 p.
Abstract
The emulsifying ability of surfactants is determined by the presence of hydrophobic and hydrophilic functional groups. The properties of the emulsifier affect the dispersed phase average size. Edible refined sunflower oil was used to prepare the emulsions. In the composition of oils, even after refining, small amounts of accompanying components are found after the plant tissues destruction. This allows the vegetable oil to be emulsified without surfactants addition. The article examined emulsions without the addition of surfactants and with sodium lauryl sulfate, as one of the most common components of detergents in the Russian Federation.
The purpose of the research was to study the colloidal chemical characteristics of vegetable oil emulsions in water and the influence of their properties on the efficiency of sorption purification. It has been shown that sodium lauryl sulfate in an amount of 0.05 mg/dm3 in the sunflower oil-water system leads to a decrease in the average diameter of oil droplets, as well as to a change in the ζ – potential of the oil micelle, from a weakly positive one it goes into a weakly negative region with an increase in charge as the emulsifier concentration increases. In the presence of an emulsifier, the efficiency of extraction of vegetable oils from aqueous media using the OSP600 sorp-tion material decreases.
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Analysis of physical and chemical processes of sulfur removal during agglomeration of ore raw materials

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 14-27 p.
Abstract
This paper analyzes the physical and chemical processes of sulfur removal during agglomeration of iron ore mineral raw materials to build a technologically efficient processing model. Thermodynamic aspects of the formation of sulfates are considered, taking into account the features of desulfurization of calcined ore materials in the presence of alkali-earth metal compounds in the charge of agglomerates, when sulfur dioxide is partially captured by them. It was found that the addition of limestone to concentrate and pure pyrite has no noticeable ef-fect on the removal of sulfur from the charge in the temperature range of 600-900 ° C during short-term firing due to the weak absorption of calcium carbonate by sulfur dioxide. Analysis of the agglomeration processes of sulfu-rous iron ore materials found that free lime absorbs sulfur well, since an intermediate stage is necessary for lime-stone absorption – dissociation of calcium carbonate. The factors contributing to decarbonization, which lead to a more complete removal of sulfide sulfur from oxidized iron ore materials, have been investigated. The thermody-namic analysis carried out by the authors allowed us to scientifically substantiate the experimentally observed in-tensification of the dissociation reaction of sulfates with an increase in temperature, a decrease in the partial pres-sure of oxygen in the furnace atmosphere during the processing of iron ore agglomerate. The data obtained in the study show that in oxidizing and slightly oxidizing conditions, sulfates decompose with increasing temperature if their contact with silicon and iron or aluminum oxides is ensured, and the formation of a melt accelerates mass exchange and promotes desulfurization. It is revealed that at the same time, liquid-phase sintering intensifies, in-hibiting the release of gases. In the conditions of the agglomeration process as a whole, the atmosphere is oxidiz-ing, although in some micro-volumes near the burning coke particles, the reducing potential of the gas phase is possible. Therefore, it makes sense to consider a uniform ratio between sulfate and sulfide sulfur in various gaseous environments.
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Overview of surfactant flooding as a method of increasing oil recovery and the applicability of microcapsulation technology to improve the efficiency of surfactant flooding

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 28-47 p.
Abstract
The problem of increasing the degree of oil recovery from reservoir formations has remained relevant over the past few decades.
Currently, there is a rapid increase in interest in chemical methods of increasing oil recovery to intensify oil production, in particular, flooding with surfactants (surfactants).
This article describes the factors affecting the efficiency of self-winding and the effect of adsorption on the eco-nomic component of the technology. To solve the problem of adsorption, preventing the large-scale introduction of surfactant, it is proposed to use the technology of microencapsulation of surfactants in a solid shell.
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Effect of nanostructure and surface morphology on Al2O3 coatings carried out during thermochemical treatment

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 48-64 p.
Abstract
The influence of thermochemical treatment of Al2O3 layers on their chemical composition, nanostructure, micromechanical and sclerometric properties, and surface morphology is presented. By anodizing in a three-component direct current electrolyte, oxide layers were obtained by means of an aluminum alloy EN AW-5251 (AlMg2). Thermochemical treatment was carried out directly in aqueous solutions of Na2SO4·10H2O and Na2Cr2O7·2H2O, as well as in water purified from mineral salts. A thermochemical treatment method is presented that transforms the surface structure of the layers (formation of a sublayer of Na2Cr2O7·2H2O and Na2SO4·10H2O) and significantly changes the thickness of the layers by 0.37 and 1.77 microns, respectively. It was revealed that thermochemical treatment in water led to the formation of a sublayer 0.63 microns thick. Micro-mechanical tests have shown an increase in the surface microhardness of layers in the case of their thermochemical treatment in water and Na2SO4·10H2O, as well as a decrease in layers modified in Na2Cr2O7·2H2O solution. The layer modified in Na2SO4·10H2O solution has the highest microhardness (7.1 GPa). Scratch tests indicate that thermochemically treated layers have better adhesive properties than the control layer. The optimal constancy with respect to scratches was demonstrated by the layer as a result of thermochemical treatment using a solution of 10H2O · Na2SO4 (the highest values for almost most critical loads), relates it to sliding contacts, which is provided with high load capacity and insignificant roughness.
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Adsorption of kappa-carrageenan on the surface of chitosan and its sulfuric acid salt and stabilization of chitosan-sulfate nanoparticles by it

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 5-18 p.
Abstract
Objectives: to investigate the adsorption of k-carrageenan on the surface of chitosan at pH 7.4 and chitosan treated with dilute sulfuric acid solution (pH 2.5-2.7). To develop a method for obtaining the sol of the chitosan sulfate salt - chitosan sulfate (CX) and to investigate its stability in time depending on the use of various acids as precursors, and its increase with the addition of different concentrations of k–carrageenan.
Methods. To determine the viscosity of polymer solutions, their molecular weight and to study the adsorption of k-carrageenan on CX, the method of capillary viscometry was used. The assessment of the stability of the zones over time was carried out photometrically.
Results. The adsorption of k-carrageenan on chitosan and CX has been studied: experimental isotherms of k-carrageenan adsorption have been constructed.on the surfaces of chitosan and CX, the constants of the Langmuir equation are calculated and complete theoretical adsorption isotherms are constructed using them. A method for obtaining a CX hydrosol with a positive particle charge has been developed. The stability of CX sols in time both without additives and with additives of k-carrageenan in time has been studied.
Conclusions. The adsorption of k-carrageenan on chitosan and CX is monomolecular. The adsorption equilibrium constant is greater with the adsorption of k-carrageenan on the surface of CX, and the maximum adsorption value is greater with the adsorption on the surface of chitosan. Of the acids used as precursors, the sol obtained using citric acid has the greatest stability. With an additional additive to the sols of the protective colloid - k-carrageenan to sols obtained using hydrochloric acid and citric acid, the sol obtained with the use of hydrochloric acid and carrageenan additives in the range of 0.04-0.06% has the greatest aggregate stability.
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Energy-efficient nanocomposite membrane-electrode blocks for chemical current sources

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 19-28 p.
Abstract
Electrode materials based on platinum metal nanoparticles are widely used to create alternative energy sources with high specific characteristics. Industrial carbon-containing carriers and perfluorinated proton exchange membranes of the Nafion type are used as matrices for the fuel cell electrodes formation. In this work, new effective polymer-carbon catalysts modified with platinum nanoparticles have been synthesized. Physicochemical and functional characteristics of nanocomposites have been studied by electron microscopy, X-ray phase analysis, small-angle X-ray scattering and cyclic voltammetry. Increased catalytic activity and stability of the formed electrodes in hydrogen-oxygen fuel cells had been found. The test results of hydrogen-air fuel cells in model operating conditions had been obtained. The current density maximum parameters of the membrane-electrode assemblies had been found for nanocomposites formed on multi-walled carbon nanotubes with a solubilization coefficient of ω equal to 1.5 and a platinum content of 0.35 mg/cm2. The creation of new membrane-electrode assemblies helps to reduce the cost of chemical current sources, as well as increase their energy efficiency.
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