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2023

Archives Journal Chemical Bulletin Vol. 6

Using the spectrophotometric method to evaluate the properties of complex compounds of iron (III), copper (II) and magnesium with organic ligands

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 29-37 p.
Abstract
In this paper, we propose a spectrophotometric method for assessing the effect of organic ligands on the oxidizing properties of complexing agents (iron (III), copper (II)) and on the heterogeneous equilibrium in the magnesium-hydrophosphate system. An analysis of experimental data shows that glutamic acid at a concentration in solution from 50 to 250 mg/l does not affect the reduction of iron (III), however, the interaction of copper (II) with glutamic acid reduces the ability of Cu2+ to reduce by 9% and 39% at concentration in solution from 50 to 100 mg/l, respectively. The greatest complexing interaction with magnesium, in the "magnesium-hydrophosphate" system, was shown by proton pump inhibitors: rabeprazole and pantoprazole, and the smallest - esomeprazole and omeprazole.
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Structural and morphological characteristics of layered hydroaluminosilicates activated by solutions of alkali metal chlorides

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 38-49 p.
Abstract
This study presents the results of a comparative investigation into the chemical and mineralogical compositions, as well as the structural-morphological characteristics of enriched and modified forms of clay, which contains layered hydroaluminosilicate – montmorillonite – as its main mineral phase. Impurity minerals in the clay raw material include kaolinite, low-temperature trigonal quartz, calcite, and illite, whose presence is confirmed by transmission electron microscopy and infrared Fourier spectrometry. Activation of the enriched rock was performed by treating it with solutions of alkali metal chlorides – lithium, potassium, and sodium chlorides. It is shown that the original form of the clay does not contain Na2O and Li2O oxides. However, through the salt treatment of the enriched hydroaluminosilicate rock, products with a content of lithium, sodium, and potassium oxides were obtained, amounting to 1.96%, 3.98%, and 6.28% by mass, respectively. It is established that the treatment with potassium chloride solution has the most significant influence on the structural-morphological characteristics of montmorillonite clay. Specifically, the sample treated with KCl solution exhibits an increased tendency towards particle aggregation and the formation of relatively large, spherical grains. It is also shown that the activated product mentioned above is almost entirely devoid of the mineral phase known as calcite. Meanwhile, the impact of LiCl and NaCl salt solutions on the enriched clay raw material hardly alters the microstructure of the resulting products.
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Kinetics of Cu(II) removal from aqueous solution with the use of Fe3O4/C nanocomposite

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 5-12 p.
Abstract
this work studied the sorption kinetics of the Fe3O4/C nanocomposite obtained by heating polyacrylonitrile (PAN) and FeCl2∙4H2O in air, the preparation procedure of which was described in the previous works [9, 10]. The main task was to calculate the sorption characteristics and check the practical application of this nanocomposite, that is the possibility of purification from heavy metals from water sources, verified on the example of modeling the sorption of copper ions from an aqueous solution of copper(II) acetate hexahydrate, hence the equations of diffusion (Morris-Weber model) and chemical kinetics (Lagergren's pseudo-first order, Ho and McKay's pseudo-second order), as well as the Elovich chemosorption model were applied. Analysis of the data illustrated that the diffusion of copper ions inside the pores of the nanocomposite and chemical interactions between copper ions and functional groups of the sorbent surface, such as hydroxyl, carboxyl, carbonyl, etc., which are typical of carbon sorbents, contribute to the total sorption rate. Experimentally, the capacity of this nanocomposite for copper sorption was 208.4 mg/g, however, modeling showed that this value could theoretically be higher by 37%.
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Determination of the content of triterpene saponins in plant raw materials Scutellaria baicalensis Georgi and Scutellaria galericulata L. depending on the age of the plant

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 13-20 p.
Abstract
The work is aimed at determining the content of triterpene saponins in plant raw materials Scutellaria galericulata L. and Scutellaria baicalensis Georgi depending on the age and morphological parts of the plant. Plants of the genus Lamiaceae (Scutellaria baicalensis Georgi and Scutellaria galericulata L.), which were cultivated and harvested in the form of aboveground and underground parts in the Astrakhan region, were chosen as the object of analysis. In the work, raw materials of one-year-old (2019), two-year-old (2020) and three-year-old plants (2021) were analyzed. The content (%) of triterpene saponins was determined by the spectrophotometric method in terms of ursolic acid according to the State Pharmacopoeia XIV. During the experiment, it was found that differences in the content in the aboveground and underground parts relative to plants of the first and second years of life were not observed, the most significant difference was determined for the third year of collection. Revealed the reliability of differences between the content of saponins in the aboveground and underground parts for each of the plants, which can be traced for three years. In addition, the aerial part is the richest in the accumulation of triterpene compounds. Significant differences in the content of triterpene compounds of Scutellaria baicalensis Georgi relative to Scutellaria galericulata L. were observed only in the third year of harvesting raw materials. The data obtained in the study characterize a promising opportunity for further study of plant raw materials Scutellaria baicalensis Georgi and Scutellaria galericulata L. as a promising source of biologically active substances, namely triterpene compounds.
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Features of the use of ozone in water treatment in the experimental installation UL-2

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 21-29 p.
Abstract
The deterioration of water quality in water supply sources is an urgent problem both in Russia and around the world, which is why it is so important to develop new methods of water purification and filtration, which justifies the goal and emphasizes the relevance and practical significance of the research described in this article. As part of this work, pilot tests were conducted to determine ozone doses and evaluate the effectiveness of the ozonation method at a number of water supply stations. Taking into account the different chemical composition of water in the water supply sources, the convenience of transportation and installation of experimental equipment at the work site, an experimental installation UL-2 was created. The installation allows you to simulate the processes of ozonation and filtration of water. Based on the results of the tests carried out, the effectiveness of the ozonation method is determined, as well as recommendations for the hardware implementation of the water ozonation process and an assessment of its technical and economic indicators are formulated.
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Experimental studies of the effect of ozonation on the water treatment process in the design of an ozone generator

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 30-40 p.
Abstract
Purpose – this article discusses a new approach to the process of ozonation of water from the point of view of its hardware design for water treatment plants of centralized water supply. At the same time, it is shown how the quantitative use of ozone in water treatment (dose) depends on the chemical composition of water and is determined in each specific case and requires determining its place in the technological scheme. The operating characteristics of ozonators, which were used to determine design requirements and find operating modes, are considered in detail. The purpose of these studies was to conduct pilot tests to determine ozone doses and evaluate the effectiveness of the ozonation method at a number of water supply stations, including at the WTF of Tyumen, the source of the Tura river.
Methods: in the conducted studies, computational, theoretical and experimental methods were used to determine the minimum voltage at which the discharge in the discharge gap "burns" and power-amplitude voltage curves were constructed. Since the specific energy is the intensive parameter that determines the kinetics of ozone synthesis, the ozone concentration at the outlet of the ozonator and its dependence on the experimental parameters were studied during the experiments. The developed methods were used in determining design solutions at water treatment plants of the Russian Federation.
Results: it was shown that the discharge ignition voltage determines the geometry of the ozone generator itself and the pressure in the discharge gap. As a result of the research, it was revealed that the concentration of ozone at the outlet of the ozonator depends almost linearly on the specific energy and the effective dose of ozone is a key parameter in the hardware filling of ozonator complexes.
Conclusions: the projects carried out with its use received a positive conclusion of the state expertise. The equipment developed taking into account the data obtained experimentally is successfully operated as part of the ozone absorption units of water treatment facilities.
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