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Keywords: purification

Effective methods of concentration and purification of omega-3 polyunsaturated fatty acids: a systematic review and prospects

https://doi.org/10.58224/2619-0575-2024-7-4-64-86
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 64 – 86 p.
Abstract
The article is devoted to methods of concentrating and purifying omega-3 polyunsaturated fatty acids (PUFAs). The text discusses methods such as transesterification, urea complexation, chromatographic methods, low-temperature crystallization, supercritical fluid extraction, molecular distillation, and iodolactonization.
The aim of the research is to systematize literature data to identify the most effective methods for obtaining pu-rified, concentrated omega-3 PUFAs. The methods include transesterification for converting triglycerides into ethyl esters, urea complexation for separating fatty acids, chromatographic methods for high product purity, low-temperature crystallization for simplicity and cost-effectiveness, supercritical fluid extraction for environmental cleanliness and efficiency, molecular distillation for high selectivity, and iodolactonization for prospective separa-tion of omega-3 acids.
The article discusses the advantages and disadvantages of methods for concentrating omega-3 PUFAs. It also considers the prospects for developing effective and economical methods of enriching omega-3 fatty acids to re-duce costs and meet future demand for highly purified products.
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NICKEL IONS ADSORPTION BY THERMOMODIFIED FALLEN LEAVES OF CHESTNUT

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 48-59 p.
Abstract
In recent years, the attention of researchers has been attracted by industrial and agricultural waste, which can be used as sorption materials. A special group is made up of lignocellulose-containing components of woody biomass (leaves, bark, needles, fruits, etc.) and wood processing products (sawdust, shavings, chips, etc.). Advantages of using the latter as reagents for wastewater treatment include simple technique, small processing, good adsorption capacity, selective adsorption of heavy metal ions, low cost, free availability and easy regeneration. Trees foliage attracts attention аmong the components of the woody biomass, it has a large specific surface area and falls annually under the conditions of the Russian Federation, which facilitates its collection and use.
Nickel ions are one of the most toxic pollutants that enter water bodies with industrial wastewater. The infor-mation on the nickel compounds toxic effect on living organisms is briefly presented. In this work, we studied the sorption properties of chestnut fallen leaves (CFL) in relation to nickel ions. The sorption capacity maximum value of the thermally modified CFL at a temperature of 250° C (CFL250) is 1.3 mmol / g for nickel ions. By processing the obtained isotherm within the framework of the Langmuir, Freundlich, BET, Dubinin-Radushkevich sorption models, it was found that the adsorption process is most accurately described by the Langmuir model (R2 = 0.9912). The calculated Gibbs energy is equal to -7.86 kJ / mol, it indicates the occurrence of spontaneous physical adsorption of Ni2 + ions on the CFL250 surface.
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PURIFICATION OF STARCH-CONTAINING WASTEWATER

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 14-20 p.
Abstract
The paper considers the possibility of purification of starch-containing wastewater by thermally modified waste of sugar production – saturation sediment. Starchy wastewaters with a large amount of organic compounds quickly rot, create a favorable environment for the development of microorganisms, so these waters should be subjected to deep purification. Thermo-modified saturation residue (TMSR) is a fine black powder, the main component of which is CaCO3, formed during the chemical reaction between Ca (OH)2 and CO2 in saturation columns in the process of diffusion beet juicetreatment in sugar production. CaCO3 acts as a basis for the carbon layer, which covers the surface of the particles and formed during the calcination of TMSR through carbonization of organic substances contained in the original saturation sediment. The authors investigated the effect of some technological factors on the purification efficiency. It was established that 40 minutes at a temperature of the reaction medium of 20-30°C is sufficient for flow of the process. The purification efficiency of starchy wastewater systems reaches 88%.
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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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