Home – Home – Jornals – Chemistry for Sustainable Development 2020 number 4

Disorders of hematopoiesis caused by the action of various factors (hemotoxic substances, drugs, cytotoxic drugs, radiation) lead to a deviation from the norm and the development of the diseases varying in complexity. The restoration of hematopoiesis under extreme conditions is vital, and the search for the drugs stimulating hematopoiesis is an extremely urgent task. The most interesting agents are low molecular weight compounds that can stimulate hematopoiesis in case of its disorders. The presented literature review discusses various factors leading to hematopoietic disorders, and drugs that have shown sufficient effectiveness in eliminating these disorders, in particular with cytostatic therapy and the treatment of hemolytic pathologies. The review can be useful in the search for agents that stimulate hematopoiesis, and is addressed not only to medical and chemical professionals, but also to a wide range of readers.

The results of a comprehensive study of an illite-containing sorbent (IS) are presented. The sorbent was obtained by means of acid-water treatment of the sample of clay-salt slimes, which are industrial wastes of JSC “Belaruskali” (the Republic of Belarus). The material composition of the IS is established, indicating that the main clay mineral is illite, the content of which is 65.2 mass %. The specific surface area of the IS is determined to be (66 ± 4) m²/g. According to mineralogical composition, the IS refers to hydromica group. The sorption ability of the IS sample to extract ¹³⁷Cs⁺ from natural waters of different chemical composition was studied. It is shown that the major ions of natural waters, namely Ca²⁺ and Na⁺, do not have a significant effect on the sorption of ¹³⁷Cs⁺ by the IS for pH of water solution within the range of 5-9. It is determined that the IS has shown high selectivity with respect to ¹³⁷Cs⁺ sorption from aquatic medium, and the main competitor is K⁺ ion. When K⁺ concentration in the aquatic medium is higher than 0.5 mol/dm³ in, the sorption of ¹³⁷Cs⁺ on the IS is completely inhibited. It is established that IS sorbs ³⁷Cs⁺ from natural water 2-4 times more efficiently than clinoptilolite of the Shivertuinskoye deposit (Chita region, Russia), which is currently used as a sorbent of ¹³⁷Cs⁺. The obtained results indicate the possibility and prospects of using CSS reserves accumulated in the Republic of Belarus to manufacture the IS and to use it for purification of aquatic medium from ¹³⁷Cs⁺, as well as for solving a number of environmental problems, including rehabilitation of radioactively contaminated soils and territories.

The effect of KOH concentration on the rate of the target reaction of metal tellurium deposition from alkaline tellurite solutions and on the rate of the side reaction of tellurium dissolution was studied by means of voltammetry with the linear potential scanning on a graphite electrode coated with tellurium deposit. It was established that KOH only weakly (with a change by 5-10 %) affects the rates of the target and side reactions within the range of alkali concentrations 2-4 M, which is used for the production of tellurium. The reasons of a decrease in the rates of the target and side reactions at low alkali concentrations were considered. It was shown that the target and side cathode reactions have the diffusion-determined nature in the range of alkali concentrations 0.5-4 M with tellurium deposition and 0.1-4 M with tellurium dissolution. The side cathode reaction of Те dissolution has a one-electron mechanism, and it requires 20 % of the amount of electricity used for tellurium deposition.

Nickel-containing zeolite samples were prepared by dry mechanical mixing of ZSM-5 zeolite (silica modulus 40) and nickel powder with the average particle size of 50 nm in the amount of 0.5 mass %. The samples were mechanically treated in a ball mill for 24-120 h. The crystallinity of the initial zeolite and mechanically treated nickel-containing zeolites was determined by means of IR spectroscopy and XRS. The degree of zeolite crystallinity was revealed to decrease due to loosening of the structure of both the polycrystalline units and primary crystallites as a result of mechanical treatment. The analysis of the state of nanosized nickel in zeolite catalysts by means of UV spectroscopy and XPS revealed almost complete absence of the oxidation of nickel particles. The morphology of the crystals of the initial and mechanically treated zeolites was studied by means of the high resolution transmission electron microscopy. Mechanical treatment was determined to cause a decrease in the particle size of initial ZSM-5 and partial migration of nickel from the surface into zeolite pores. The size of nickel particles decreases during the initial period of mechanical treatment, while a longer mechanical impact, on the contrary, contributes to the agglomeration of nickel particles. The particles of ZSM-5 zeolite in the initial sample look like coarse agglomerates with the overall size of several micrometres. The agglomerates are composed of smaller polycrystalline units 0.5-1.0 mm in size. However, the primary particles are zeolite crystals 50-100 nm in size. Mechanical treatment causes disintegration of coarse zeolite agglomerates into smaller polycrystalline units less than 1 mm in size; primary crystallites comprising the polycrystalline structure are dispersed, too, decreasing in size to ~50 nm. According to the data of low-temperature desorption of nitrogen, mechanical pretreatment of nickel-containing zeolite causes a decrease in its specific surface and pore volume. The changes in the physicochemical properties of the Ni/ZSM-5 catalyst caused by mechanical treatment should promote selective conversion of feedstock components and flexibility of the regulation of selective formation of target products in oil refining processes.

A fundamentally new concept of providing the population with high-quality drinking water is proposed, associated with the transfer of drinking water supply to cities and villages to the use of autonomous block installations for water purification in the sites of its direct consumption. Autonomous membrane installations for collective and individual use with biotesting and analytical control are developed. In these installations, preliminary water purification is carried out with the help of microfiltration tubular membranes made of lignocellulose (wood) and ceramic membranes made of clay minerals, which retain mechanical and colloidal impurities. The concentrations of these impurities after purification meet the drinking water standards. A technological scheme is developed for water purification from nitrate ions to drinking conditions with the production of mineral fertilizers through a rational combination of reverse osmosis and an improved electrodialysis process.

Complex coagulants comprise a developing and very promising area for the processes involved in the treatment of natural and waste waters. In spite of somewhat higher cost, complex coagulants are devoid of the disadvantages of many classic coagulants and demonstrate high efficiency in water purification from metals, fats, oil products and suspended matter; they also provide a substantial decrease in the concentrations of dissolved organic substances (chemical oxygen demand). The simplest method of manufacturing complex coagulants is the introduction of an additive composed of the products of hydrolysis of titanium-containing compounds into the classic reagents based on aluminium or iron salts. Soluble titanium salts or titanium dioxide may serve as the source of titanium compounds. The waste waters of dairy industry contain a large amount of dissolved organic substances and emulsified fat, so the purification of these waters is one of the most complicated problems. Trial coagulation treatment of model wastewater containing whey showed a high efficiency of complex titanium-containing reagents. Complex coagulants exceeded traditional reagents in efficiency by 10-15 % as average, and the rate of precipitate filtration was 1.2-1.5 times higher. The sediment had a looser structure, did not clog the pores of the filtering material, and readily gave moisture off. Tests of the best samples of complex reagents with the combined household and industrial waste waters of the dairy processing enterprises of the Moscow Region confirmed their high coagulation characteristics with respect to the most common pollutants, and the acceleration of sludge filtration processes will significantly reduce the capital costs of building local sewage treatment plants. The residual content of titanium ions in water, when using the entire line of modified coagulants, did not exceed the maximum permissible level for fishery water bodies.

Porous carbon materials with a specific surface area of 1200-1500 m²/g were obtained by carbonization of rice husks at 500 °C, followed by subsequent activation using potassium hydroxide at a temperature of 700, 800, 900 °C, and studied by means of Raman spectroscopy and electrochemical methods. It was established that mechanical activation of rice husks makes it possible to increase the specific surface area (to 2315 m²/g) and the volume of micropores (to 0.84 cm³/g) in the carbon material. As a result, an increase in electrical capacity and a decrease in the internal resistance of supercapacitor cells with electrodes based on them are achieved.

Nickel catalysts supported on modified alumina were synthesized, their physicochemical properties and activity in the reaction of autothermal reforming of methane (ATR CH₄) were studied. Regulation of physicochemical and, consequently, functional properties of the samples was performed by the modification of (γ+δ)-Al₂O₃ support with the additives of different composition Ce_1-xM_xO_y (M = Gd, La, Mg; x = 0, 0.2, 0.5, 0.8 and 1; 1 ≤ y ≤ 2) in the amount of 10 mass %. It is shown that Ni/Ce_1-xM_xO_y/Al₂O₃ are mesoporous materials with specific surface area 80 ± 5 m²/g, slightly changing with the variations of the composition of modifying additive. The phases of alumina (γ+δ)-Al₂O₃, fluorite-like solid solution based on СеО₂ with an average crystallite size 9.0 ± 1.5 nm and nickel oxide NiO are present in the catalysts. The average size of NiO particles is varied in the range from 6.0 to 13.5 nm and is determined by the composition of modifying additive, decreasing with an increase of x, and in the following sequence of oxide additives: CeO₂ > MgО > Gd₂О₃ > La₂O₃. The catalysts are capable of self-activation under the ATR CH₄ reaction conditions, and this effect is enhanced in the following row of M: Mg < Gd < La, which is in good correlation with the reducibility of samples. The optimal catalyst Ni/Се_0.5La_0.5O_1.75/Al₂O₃ is revealed, providing the hydrogen yield of 80 % upon 100 % methane conversion at 850 ^oС. The use of the developed catalysts for the energy-effective conversion of natural and associated petroleum gases into the hydrogen-containing gas is promising.

The results of determining the ash content of perennial and annual plants growing near industrial zones, roads and in the urban environment of the administrative centres of the Novosibirsk Region (Iskitim, Berdsk, Novosibirsk) are presented. These plant habitats differ in the degree of anthropogenic impact on the environment, with the greatest pollution in the city of Iskitim. It is noted that the ash content of the leaves of plants of different systematic groups is determined by many factors, including species and varietal belonging, anthropogenic pollution of the environment, and the features of the growing season. A decrease in the content of ash substances in the leaves of herbaceous plants belonging to the families Hemerocallidaceae > Asteraceae > Iridaceae > Hostaceae > Laminaceae was established.

Red mud containing significant amounts of alumina, iron oxide, titanium dioxide and other valuable components (Ga 0.003-0.005 mass %, V 0.050-0.099 mass %) is the main waste in the alkaline extraction of alumina from alunites according to the Bayer method and a promising raw material for obtaining gallium and vanadium. The degree of sulphatization of gallium and vanadium from red mud during sulphating roasting was investigated. The technological scheme of sulphating process includes three main stages: 1) missing the moistened initial material with concentrated sulphuric acid; 2) sulphating roasting; 3) water leaching of the sulphated mass. The majority of minerals are transformed through sulphatization into the corresponding sulphate compounds. During subsequent roasting, unstable sulphates (mainly ferric sulphate) are decomposed to form the corresponding oxides, while other metals remain in the form of sulphates (Al₂(SO₄)₃, Ga₂(SО₄)₃, VOSO₄). As a result of leaching of the sulphated mass with water, iron and silicon oxides stay in the residue, while the sulphates of aluminium, gallium and vanadium pass into solution. The maximal degree of gallium and vanadium sulphatization under the conditions of laboratory experiments was detected within the range of 600-640 °C. The determination changes in the mineralogical composition of the sulphated mass of red mud were studied by means of thermogravimetry and differential thermal analysis. The developed method of gallium and vanadium extraction from red mud is distinguished by its simplicity and efficiency.

The high cost of hydrocatalytic processes is the reason of the attention of researchers to the search for alternative ways to process high-sulphur vacuum distillates. Pre-oxidation followed by cracking is considered as a promising method for refining petroleum products. This approach enables efficient destruction of polyaromatic sulphur-containing compounds in heavy hydrocarbon raw materials yielding additional amounts of distillate fractions. The effect of nano-sized molybdenum powder on the composition and quality of the products of cracking of vacuum gasoil oxidized preliminarily with a mixture of hydrogen peroxide with formic acid was investigated. It was demonstrated that the use of an optimal amount of nanosized molybdenum powder as the additive allows a substantial decrease in gas generation due to a decrease in the rates of aromatization and dealkylation of the oxidized high-molecular compounds including sulphur-containing ones. The effect of the amount of Mo additive on the transformation patterns of such sulphur-containing compounds as thiophene, benzo- and dibenzothiophene during the combined process was revealed. The changes in the structural-group parameters of resins and asphaltenes in the products of cracking of oxidized vacuum gasoil in the presence of the additive in different amounts were investigated. The data obtained allow us to extend our understanding of thermal transformations of the oxidized components of vacuum gasoil, which is an important step in the development of a technological scheme for processing high-sulphur gasoils relying on the combination of preliminary oxidation and cracking.