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Shachneva E.Yu.

Candidate of Chemical Sciences (Ph.D.), Professor of RANS, Astrakhan State University

MAIN FEATURES AND CHARACTERISTICS OF CHEMICAL AND PHYSICAL-CHEMICAL METHODS OF ANALYSIS OF SURFACTANTS

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 4-15 p.
Abstract
One of the most acute and pressing problems of sustainable development in the coming century can be providing the population with quality drinking water. According to estimates of the World Health Organization, the frequency of diseases arising from the use of poor-quality drinking water is the highest. Pollution of the environment by surfactants is a great danger to the entire biosphere. Unlike organic substances, they are not subject to degradation and, in addition to the direct toxic effect on living and plant organisms, tend to accumulate in food chains, which increases their danger to humans.
The flow of surfactants into reservoirs occurs mainly from man-made sources. With the inefficient purification of water, surfactants enter the natural reservoirs, the soil, and along trophic feeding routes reach people. Accumulating in reservoirs, surfactants have a strong toxic effect on the flora and fauna, worsen the organoleptic characteristics of water, prevent the processes of self-purification of water bodies. Even small amounts of surfactants cause abundant foaming, disrupt oxygen exchange in water bodies, and inhibit photosynthesis.
To achieve one hundred percent purification of wastewater from surfactants is almost impossible. In this connection, the search for new and improvement of existing methods of analysis of surface-active substances is very important.
The article presents the main features and characteristics of chemical and physico-chemical methods for the analysis of synthetic surfactants.
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ON THE RELATIONSHIP BETWEEN THE CONTENT OF CHEMICAL ELEMENTS IN RAW MATERIALS WITH DEBYE TEMPERATURE

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 34-41 p.
Abstract
The relationship between the content of heavy metals in plant raw material with such an important integral physical parameter as the Debye temperature of a metallic element is considered. This is confirmed by the high values of the correlation coefficient. This parameter is calculated for cadmium, lead, copper, manganese, nickel, chromium and zinc ions.
The graphical dependence of the accumulation coefficient k of heavy metals from the soil is presented for the wild grassy plants of the Lower Don. Wetweed ambrosia (Ambrosia artemisiifolia L.), tansy (Tanacetum vulgare L.), Austrian wormwood (Artemisia austriaca Pall. ExWilld.), Cedar grass (Elytrigia repens (L.)) are considered. Samples were taken at a distance of 1 km from Novocherkasskaya SDPP.
The value of the mobilization factor (the factor of technogenic enrichment) of EF is described as the ratio of the technogenic flow of a chemical element to a natural element, in the transfer of metallic elements. Dependences of the mobilization factor (EF) on the Debye temperature of the metal are presented.
The dependence of the heavy metals content in the soil-vegetation-invertebrate animals system in steppe biogeocoenoses on the Debye temperature of the metal is characterized. This will allow us to predict the possible mechanism for the transport of heavy metals in nature.
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THE INFLUENCE OF THE METHOD OF COPPER SURFACE TREATMENT ON THE INTERACTION WITH ORGANIC LIGAND IN NON-AQUEOUS SOLVENT

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 16-18 p.
Abstract
Oxide films on the metal surface in the presence of dissolved oxygen in the organic solvent interact with the dissolved ligand to form a complex compound. The effect of preliminary treatment of the copper surface on the interaction with a ligand of salicyl alanine and α-benzoinoxime in a non-aqueous solvent of dimethylformamide and methylpyrrolidone is considered. The ligand concentration is 0.01 mol / l. The surface treatment of copper was carried out in a 12% solution of hydrochloric acid; by electrochemical deposition of copper on a copper substrate; treatment with 10% nitric acid solution; electrochemical polishing; The untreated surface of copper (spontaneous oxide and hydrocarbonate films) was used; chemical polishing; mechanical restoration; treatment with 30% and 68% nitric acid solution. The highest rate of dissolution is characteristic for samples pretreated with 12% (3,6 M) hydrochloric acid, as well as for samples whose surface was formed by electrolytic precipitation of copper from an acid solution of copper sulfate.
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METHODS OF SORPTION CONCENTRATION OF SURFACE ACTIVE SUBSTANCES

 24-30 p.
Abstract
The scarcity of water resources and their pollution speaks about the need to provide the population with environmentally safe drinking water. This problem is very relevant at the present time. Accumulating in reservoirs, surface-active substances exert a strong toxic effect on flora and fauna, impair the organoleptic characteristics of water, and hinder the processes of self-purification of water bodies. The processes of destruction of the majority of surfactants in natural waters occur rather slowly. One of the effective ways to combat water pollution by surfactants is to prevent them from entering water. Many of the techniques are laborious enough, they require expensive equipment, they are not precise enough and express. Therefore, the development of simple, rapid, accessible techniques suitable for determining the content of surfactants of different classes in soils, sewage and other objects is still an important and urgent task. The article describes methods of sorption concentration of surface-active substances with the use of inorganic residues, and with the use of natural and synthetic sorbents. In the methods of sorption concentration of surfactants with the use of inorganic residues, as precipitating agents and sorbents, oxides of calcium, magnesium, aluminum, marble chips, bischofite, magnesium sulfate can be simultaneously used. A method using electrochemical destructive oxidation is also used. Natural sorbents include various natural porous hydrophobic materials, which, due to their structure, possess considerable sorption ability. Natural sorbents are very diverse because of the difference in structure and conditions of their formation. These include inorganic products of natural precipitation reactions (bauxites, laterites, ferrolites, etc.), clays (hydroaluminosilicates), active earths (sili-cates), as well as organic precipitates and products of the transformation of organic substances of plant and animal origin (muds of lakes and seas, humus, peat, lignite, etc.). The process of application is quite expensive, which sig-nificantly reduces the economic efficiency of the use of natural sorbents.
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SORPTION-PHOTOMETRIC DETERMINATION OF ANIONIC SURFACTANTS IN THE PRESENCE OF ORGANIC REAGENT

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 27-36 p.
Abstract
The article describes the characteristics of a class of surfactants and the use of substances in the petrochemical industry. The classification of anionic surfactants is considered. The main structural elements of the structure of substances of the considered class are presented. A brief description of the most commonly used methods for the analysis of anionic surfactants is given. Advantages of using photometric, extraction-photometric and spectrophotometric methods for the determination of anionic surfactants using triphenylmethane dyes are described. In the course of the study, the content of the anionic surfactant (sulfonol) in the solution was monitored spectrophotometrically using the indicator reaction with malachite green. The use of the method in question to study sorption processes in a surfactant system is justified by the fact that surfactants are able to form complex compounds (ionic associates) with organic reagents with characteristic light absorption bands.
The results of a photometric determination of an anionic surfactant (sulfonol) using an organic reagent, malachite green, are presented. The effect of the acidity of the environment on the process of adsorption of a component in aqueous solutions is described. A calibration graph for determining the concentration of the component is given.
The main thermodynamic parameters of sulfon adsorption on activated carbon, such as enthalpy (∆H), isobaric-isothermal potential (∆G) and entropy (∆S) sorption were determined during the research. The obtained research results can be used for quantitative determination of the component and modeling of adsorption mechanisms.
The main characteristics of the sorption kinetics of a surfactant (sulfanol) on active coal are calculated. Isotherms of sorption kinetics are given. The possibility of purification from the above-described component using the sorbent under consideration is described.
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ABOUT CONNECTION OF LIQUACTION WITH THE DEBYE TEMPERATURE

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 41-46 p.
Abstract
The article describes the concept of liquation. Within the framework of the research, the definition of the concept described is given. The types of liquation (zonal and dendritic) are given. It is established that a number of parameters characterizing the segregation process are related to the characteristic Debye temperature of a chemical element. The interrelation between the values of the effective atomic radius, intensity, and also the liquation coefficient from the Debye temperature is considered. The role of the values of the maximum supercooling parameter on the Debye temperature is described. The dependence of the content of elements in interdendritic volumes on the Debye temperature is considered. The dependence of the chemical composition of local regions on the Debye temperature is given. A similar trend was observed with the values of the viscosity of the molten metal. The correlation coefficients always exceeded 0.9.
It should be noted that the liquation process adversely affects the steel properties. This can affect the values of the toughness of transverse specimens. The considered dependences of the process parameters can be useful for describing the processes of eliminating the heterogeneity of steels. All this will not only improve its properties, but also describe in more detail the process of eliminating the chemical heterogeneity of steel. In addition, this will allow us considering the melting process with a change in volume. Increased interest causes the content of elements in the axes of the dendrites in the initial cast state. It was found that the distribution of elements in the axes of dendrites in interdendritic microvolumes in the structure of the pressed steel does not depend on the quenching method. For the dependence considered, the values of the correlation coefficient are calculated. The main conditions of the quenching process as well as the content of the elements in percent are given.
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