Alternative Sources Of Raw Materials Research Articles

Current recycling innovations to utilize e-waste in sustainable green metal manufacturing.

The ever-increasing market demand and the rapid uptake of the technologies of electronics create an unavoidable generation of high-volume electronic waste (e-waste). E-waste is embedded with valuable metals, alloys, precious metals and rare earth elements. A substantial portion of e-waste ends up in landfills and is incinerated due to its complex multi-material structure, creating loss of resources and often leading to environmental contamination from the release of landfill leachates and combustion gases. Conversely, due to the ongoing demand for valuable metals, global industrial and manufacturing supply chains are experiencing enormous pressure. To address this issue, researchers have put multifaceted efforts into developing viable technologies and emphasized right-scaling for e-waste reclamation. Several conventional and emerging recycling technologies have been recognized to be efficient in recovering metal alloys, precious and rare earth metals from e-waste. The recovery of valuable metals from e-waste will create an alternative source of value-added raw materials, which could become part of supply chains for manufacturing. This review discusses the urgency of metal recycling from e-waste for sustainability and economic benefit, up-to-date recycling technologies with an emphasis on their potential role in creating a circular economy in e-waste management.This article is part of the discussion meeting issue 'Sustainable metals: science and systems'.

Порівняння ущільнюваності асфальтобетонної суміші із золою-винесення та вапняковим наповнювачем

Introduction. In Ukraine, about 30 % of all electricity is generated from the combustion of solid fuels — coal, shale, peat. In our country, there are about 15 operating thermal power plants that generate about 5 – 6 million tons of ash and slag waste per year as a secondary product. Thus, the fuel and energy complex waste generated in the furnaces of thermal power plants is a huge accumulation of ash in the form of dusty residues and lumpy sludge, as well as various ash and slag mixtures. These products of high-temperature processing (1 200 – 1 700 ºС) of the mineral part of the fuel are widely used in many countries of the world and, given the global trend towards an increase in the share of the secondary market for the use of waste, it is necessary to predict an increase in the rate of their processing in Ukraine. Problem Statement. The road construction industry is one of the strategic industries of Ukraine, and the issue of quality and availability of basic building materials for road construction is particularly acute now, which is directly related to its high material intensity. The known reserves of high-quality raw materials that could be used as asphalt concrete components are constantly decreasing, so it is necessary to look for alternative sources of raw materials for construction materials and explore the possibility of their use. In this regard, the most effective use of local raw materials is the use of industrial waste, which can be one of the solutions to the problem of lack of raw materials of inorganic origin.

INVESTIGATION OF WETTABILITY, ANTIBACTERIAL ACTIVITY, THERMAL INSULATION, AND MECHANICAL CHARACTERISTICS OF ELASTOMER BLEND ADHESIVES WITH HIGH-DENSITY FIBERBOARD WOOD AND ALUMINUM

Attention has recently been given to finding alternative and sustainable raw material sources for wood and metal adhesives, such as polyvinyl alcohol (PVA), corn starch (CS), arabic gum (AG), and dextrins (D). Modifying polymer dispersion using unique substances, such as modifying reactive elastomer liquid (EL) using PVA, CS, AG, or D results in sufficiently moisture-resistant adhesive joins. In the present study, the physical characteristics of EL/blended with the natural polymers PVA, CS, AG, and D, based on high-density fiberboard (HDF) wood and aluminum (Al) adhesives and coatings, were investigated and compared to those of pure EL. The EL was blended with PVA, CS, AG, or D at a ratio of 60/40 (w/w) to form EL/blends. The chemical structures, surface and interface morphology, adhesion strengths (including shear strength and pull-off strength), surface roughness, wettings, color intensity, and thermal insulation of the prepared EL and EL/blends were investigated. A scanning electron microscopy (SEM) investigation confirmed filler dispersion and adhesion between the blends, and coated HDF wood, or Al. The developed EL/AG blend had a pull-off strength of 144±5 and 102±3 MPa and a shear strength of 771±11, and 52±3 N with HDF wood and Al substrate, respectively. The EL/PVA blend had a maximum surface roughness value 4.57 µm, and its average water contact angle (WCA) was 85.6°. A plasma jet was used to treat the surface roughness and hence the wettability of the pure EL and the EL/blends, for example, plasma treatment decreased the roughness of the EL/AG blend from 4.36 to 3.28 μm. WCA, and hence wettability, was also significantly influenced by plasma treatment, for example, plasma treatment decreased the WCA of the pure EL from 71.7±0.4° to 30.7±0.7°. The lightness value of the EL/blends was less than that of the pure EL, indicating that (the color adhesives have darkened). Similarly, the yellowness-blueness and redness-greenness values of the EL/blends were greater than those of the pure EL,( rendering the blended adhesives more reddish and bluish). The EL/AG blend was found to have a minimum thermal conductivity (of 0.27 W/m.K), indicating maximum insulation.

PREPARATION AND STANDARDIZATION OF EXPERIMENTAL BATCHES OF "PHOTORAN E6, LYOPHILIZATE FOR THE PREPARATION OF SOLUTION FOR INFUSIONS", A DRUG FOR PHOTODYNAMIC THERAPY USING HOGWEED LEAVES AS RAW MATERIALS

Introduction. In recent years, there has been a sharp increase in the number of oncological diseases associated with more frequent detection of malignant neoplasms, including in the early stages. Photosensitizers are widely used for the diagnosis and treatment of oncological diseases. Already at the beginning of the twentieth century, it was discovered that a cancer cell is able to accumulate and retain colored substances [1]. In Russia, the photosensitizer "Photoran E6, lyophilizate for the preparation of an infusion solution" is widely used for the diagnosis of malignant tumors. The sub-stance for its production is sodium chloride E6, obtained by chemical synthesis from methylpheophorbide A. which, according to the patent, is extract-ed from the biomass of the green microalgae Spirulina Platensis, native to Japan and California. In this regard, there is an urgent question of replacing imported intermediates with more affordable ones. For this purpose, Sosnowski's hogweed (Heraculum sosnowskyi) was chosen. In connection with the above, the aim of this study was to obtain and standardize in terms of quality the finished drug for photodynamic therapy "Pho-toran E6, lyophilizate for the preparation of an infusion solution" produced from sodium chloride E6, synthesized using a new type of raw material (leaves of borscht Sosnowski). Material and methods. The object of the study was three series of the finished medicine product (hereinafter referred to as GLS) "Photoran, lyophi-lizate for the preparation of an infusion solution", produced from an active pharmaceutical substance synthesized from methylpheophorbide a, ob-tained, in turn, from the leaves of borscht Sosnovsky as an alternative source of vegetable raw materials [2]. The quality indicators of the finished me-dicinal product were determined according to the methods described in the regulatory documentation in accordance with the Regulatory Documentation of the XIV and XV editions. Results. For the research, the aseptic production of three series of GLS was carried out from the previously produced active pharmaceutical sub-stance Sodium Chloride E6. AFS was synthesized from an intermediate obtained from the leaves of borscht Sosnowski. The standardization of the ob-tained series of the drug has been carried out. The possibility of using Sosnowski's hogweed as a plant raw material for the production of photosensi-tizers based on chlorophyll derivatives has been evaluated. Conclusion. In the course of the study, the technology of aseptic production of GLS "Photoran, lyophilizate for the preparation of solution for infusions" was implemented. The quality indicators of the three produced batches of the finished drug have been determined.

Prospects for the use of Foam Glass Products in the Foundation of Buildings and Structures on Long Term Frozen Soils

The degradation of permafrost is the reason for the increase in deformability of the foundations of buildings and structures built on long term frozen soils. It is necessary to develop geotechnical solutions that guarantee their operational reliability in a warming climate. The introduction of foam glass for use in the cryolithozone as thermal insulation solutions making it possible to preserve the frozen state of the soils of the bases is relevant. This will make it possible to limit the use of materials with lower durability. The existing scope of application of foam glass in Russia and the prospects for the use of foam glass products in the permafrost zone are considered. The high prospects of using foam glass at the base of buildings and structures on permafrost soils are determined by its physico-mechanical and thermos-physical characteristics such as durability, low water absorption and environmental safety. These properties of foam glass make it a promising material for use in the long term frozen soils zone. The main advantages of foam glass in comparison with its analogues are also low sorption capacity and capillary absorbency, high strength, fire resistance and resistance against aggressive media. In the production of foam glass for use in the cryolithozone, it is possible to use alternative local sources of raw materials: aluminosilicate and siliceous rocks. This will reduce the cost of the material, make it more affordable and increase sales volumes.

Secretory structures and histochemistry of roots, stem, and leaves of medicinal plant Fibraurea tinctoria Lour.

Fibraurea tinctoria Lour. (Menispermaceae) is a medicinal plant used by many local tribes in Indonesia and other countries. This species has pharmacological potential, such as antimalaria, antibacterial, antitumor, antioxidant, anticancer, antidiabetic, anti-inflammatory, and hepato-protector. However, the secretory structures and sites of secondary metabolite accumulation still need to be studied. This study aimed to explore the secretory structures and reveal the accumulation sites of the main classes of secondary metabolites in the root, stem, and leaves of F. tinctoria. Histochemical analysis using various specific reagents was performed on freehand sections of the fresh organs to detect alkaloids, phenolics, terpenoids, and lipophilic compounds. Observations of secretory structures were carried out using light microscopy. The result showed that idioblast was the predominant secretory structure in the plant organs and contained all the chemical groups investigated, while laticifer accumulated alkaloids were found only in the stem. Some secondary metabolites were localized in the xylem, intercellular space, and cuticle layer. Crystals were observed in the root, stem, and leaf of this species. These results might be helpful as guide information for extracting the particular plant parts to obtain the desired secondary metabolites. It suggested that leaves are a potential alternative source of medicinal raw material of this species, in addition to the stem. RESEARCH HIGHLIGHTS: The first study on secretory structures of Fibraurea tinctoria. Secondary metabolites in F. tinctoria organs accumulate in specialized and unspecialized structures. The idioblast is the primary secretory structure in the organs of F. tinctoria spreading over the root, stem, and leaves.

The Effects of Animal Bone Ash on Asphalt Pavement Mixtures

This study focuses on alternative raw material sources to meet the demand for sustainable construction materials. Particularly, it is suggested that waste materials, such as animal by-products, could provide a solution for enhancing the mechanical properties and durability of asphalt concrete. The research aims to improve the physical and mechanical properties of asphalt concrete by utilizing bone powder obtained from Category 3 animal by-products through a hydrolysis procedure. Experiments conducted showed that the addition of 5% bone powder increased maximum stability when used in conjunction with different percentages of bitumen. Overall, some positive developments were observed in the physical and mechanical properties of asphalt concrete containing animal bone ash, possibly due to strengthening the bond between aggregate particles and bitumen material. This study highlights the potential of animal bone ash in improving the mechanical properties of asphalt concrete and recommends a 5% bone powder addition for optimum stability and durability. However, further research and field tests are needed to better understand the long-term effects of animal bone ash and its performance under different road conditions.

Investigation of the possibility of using depleted bauxite in alumina production at the Pavlodar aluminum plant

The topic of processing low-grade or low-quality bauxite is highly relevant in modern conditions due to the gradual depletion of high-quality bauxite reserves. Consequently, there is an increasing need to explore alternative sources of raw materials for aluminum production and its derivatives. Processing low-quality bauxite ores can become an effective solution, reducing dependence on limited high-quality resources and ensuring production stability in the long term. Such research has significant potential for developing technologies capable of optimizing aluminum production processes and enhancing its competitiveness in the global market. Bauxites from the Krasnooktyabrsky bauxite ore management with low aluminum oxide content (37 – 40% by mass) and a silicon module up to 2.0 are considered as potential blending materials for sintering bauxite in alumina production due to the depletion of high-quality bauxite reserves. This article presents the results of research on their processing into alumina at the Pavlodar Aluminum Plant. Laboratory and pilot-scale studies were conducted to assess the feasibility of using low-quality bauxite in alumina production and to determine the techno-economic indicators of processing. The research results confirmed the technological feasibility of processing depleted bauxites with a silicon module of 1.95 - 2.0 in the sintering section while maintaining the quality of sinter and extracting useful components. The maximum proportion of blending of depleted bauxites with the main bauxite was determined not to exceed 50%.

Innovative ceramic pigments from recycled lithium-ion battery cathodes for inkjet applications

The booming of the electric mobility together with the need of storing renewable energies have increased the demand of lithium-ion batteries which will bring about increasing amounts of electronic waste. Besides, the need for alternative sources of certain raw materials considered critical has changed the perception of determined wastes, which are no longer considered residues but sources of raw materials. In this work, the active cathode material present in end-of-life lithium-ion batteries (Ni, Co, and Mn) was used as secondary raw material, after being properly separated, in the synthesis of a cobalt iron nickel manganese chromium black spinel ((Co, Fe, Ni, Mn) (Fe,Cr)2O4). The pigment was used in the formulation of a ceramic inkjet ink which was deposited over a single-fired porous tile and porcelain tile. Texture and brightness of the ink were not affected by the use of this waste, thus presenting excellent prospects for the industrial ceramic application.

<i>Heracleum sosnowskyi</i> (Apiaceae): eradication or wise utilization of plant raw Materials?

The uncontrolled spreading of the monodominant colonies of Sosnowsky's hogweed Heracleum sosnowskyi Manden. (Apiaceae) in Russia made the researchers look for methods of using its biomass in various sectors of the economy, which should prevent its further spread. The proposed methods of using plant biomass and technologies for obtaining useful substances from H. sosnowskyi have been developed regardless of inevitable changes in populations’ characteristics: in populations on abandoned lands that are currently unaffected by anthropogenic disturbance, under regular utilization the regeneration will decrease, resulting in reduced yields and profitability of production. It is possible to maintain a high yield of hogweed necessary for its utilization only under strictly controlled cultivation, which prevents its “escape”; however, it is not possible now, as this species has been removed from the State Register of Breeding Achievements Approved for Use. At the same time, there is a sufficient range of alternative sources of raw materials that contain useful substances, which are suggested to be obtained from H. sosnowskyi. Harvesting of H. sosnowskyi for raw materials from the roadside treelines and small rivers' riparian areas is so much a problem, that it is not considered in publications, although these particular ecotopes are the constant foci of ongoing invasion. Due to the uncontrolled spread of the H. sosnowskyi, the biodiversity of agricultural lands, including wild-growing food, technical and medicinal plants (including wild relatives of cultivated plants) are under threat.

PLANT RAW MATERIAL AS A SOURCE OF METABOLITES FOR WOUND HEALING AND ANTI-SCARRING PRODUCT

Cosmeceutical products based on plant raw materials have a complex effect, are available, and low-toxic. The creation of new natural products for wound healing without tissue scarring is topical. For this, the secondary metabolites of the plant must demonstrate antibacterial, anti-inflammatory, and antioxidant effects, and have low cytotoxicity. Aim. To conduct an analysis of literary sources in electronic databases, regarding products on the market with a wound healing effect and plant raw materials that would have a therapeutic effect on wound healing without the formation of scars. Results. The characteristics of four types of scars are described. Plants and secondary metabolites are listed according to their action: antibacterial, antioxidant, anti-inflammatory, collagenstimulating, and anti-scarring. Lupeol, allicin, and cinnamaldehyde show antibacterial effect; quercetin, resveratrol, luteolin, naringenin, gallic acid, and curcumin show antioxidant effect; asiatic acid, pinocembrin, and myricetin show anti-inflammatory effect. Cryptotanshinone, bexarotene, taspine, sesamol, and astragaloside IV contribute to the deposition of fresh collagen in the wound. On the Ukrainian market, there are natural wound healing products in the form of a balm, cream, and gel. They include vegetable oils, essential oils, extracts of Thymus L., Arnica montana, Inula helenium, Aloe vera, Matricaria chamomilla, etc. Wound healing medicinal products of a chemical nature occupy a large part of the Ukrainian market, among them the products with dexapentanol predominate. The use of the cell culture method as an alternative source of plant raw materials for wound and scar treatment is perspective. The biotechnological method helps preserve biodiversity and obtain chemically pure plant raw materials regardless of environmental conditions. Conclusions. The study demonstrates the possibilities of using plant raw materials to create new cosmeceuticals with wound healing and anti-scaring effects for use in combined therapy.

Environmental and technical assessment on the application of slate waste in Portland-composite cement CEM II

Large volumes of waste are generated from the manufacture of slabs, roofing, and tiles using slate stone. The use of waste in the construction industry is prevalent due to the environmental advantages associated with the implementation of circular economy standards. This paper examines the production of Portland cement CEM II using heat-treated slate waste. The fineness index results were 10.95 % for the 75-μm sieve and 23.53 % for the 45-μm sieve. Assessment of reactivity using mechanical methods showed that mortars produced with 20 % slate waste (SW) achieved a strength of 42.35 MPa and a mechanical index of 84.93 %. Direct measurement (FTIR), along with chemical methods (Frattini Test and Saturated lime test), confirm the pozzolanic activity of the slate waste. The environmental impact assessment demonstrated a reduction in the carbon dioxide emission rate by 21.49 % (6.54E+02 kgCO2-eq/t) with the use of Portland cement CEM II/CSW. The valorization of slate waste can contribute to the availability of an alternative source of raw material and the reduction of natural resource consumption. However, further studies on mechanical performance and durability are necessary for this waste to be applied in structural cementitious matrices.

ТЕХНІКО-ЕКОНОМІЧНЕ ОБҐРУНТУВАННЯ ДОЦІЛЬНОСТІ ЗАСТОСУВАННЯ АСФАЛЬТОБЕТОННИХ ШАРІВ ІЗ ЗОЛОЮ ВИНЕСЕННЯ

Introduction. The road construction industry is currently one of the strategic industries of Ukraine, and the issue of quality and availability of basic building materials for road construction is particularly topical, which is directly related to its high material intensity. The known reserves of high-quality raw materials that could be used as asphalt concrete components are constantly decreasing, so it is necessary to look for alternative sources of raw materials for construction materials and explore the possibility of their use. In this regard, the most efficient use of local raw materials is the use of industrial waste, which can be one of the solutions to the problem of shortage of raw materials of inorganic origin. Problem statement. In road construction, when repairing or arranging road pavement layers, in particular asphalt mixtures, the need for carbonate mineral fillers, which are scarce in some regions, is constantly growing. Industrial by-products can be an alternative. One of these materials is fly ash from thermal power plants, which can be used instead of mineral fillers in asphalt mixtures. Objective. To perform a feasibility study of the use of asphalt concrete layers with fly ash. Materials and Methods. Analysis of information sources and the materials market of Ukraine and calculation of the technical and economic efficiency of fly ash application in asphalt mixtures.

Grades of cassava starch (flours) as sustainable substrates for use in neutral spirit and biofuel production—Industry approach

One way to mitigate the adverse impacts of climate change is through aggressive replacement of fossil energy sources with plant derived renewable energy. The potential of different grades of cassava starch, including decayed cassava starch, as viable alternative and cheaper source of renewable raw materials for bio-ethanol production was studied. The global population keeps expanding and poverty levels keep increasing. Conflict in the use of food-grade cassava starch as raw material for bio-ethanol production will pose a threat to food security. The highest alcohol yield (AY) of 539 LA/t dm was obtained from food grade cassava starch. Food grade cassava starch per-boiled for 5 min produced lower AY (524 LA/t dm). Cassava starch per-boiled for more than 5 min gave much lower AY (507 LA/t). The mildly decayed cassava starch gave a relatively higher AY of 491 LA/t dm than the more decayed cassava substrate that produced AY of 453 LA/t dm. The AY value obtained from the more decayed cassava starch is similar to the AY values obtained with some cereals. Decayed cassava is not fit for human consumption, would not compete with food requirements. This will assist in food security, secure our environment from pollution and other adverse effects.

Investigation of metabolic processes of alcohol yeast during the fermentation of buckwheat-corn wort

To expand the range of competitive alcoholic beverages with original organoleptic properties, it is promising to study the use of new types of plant raw materials in grain distillate technologies. The purpose of this work was to establish the influence of the characteristics of the composition of grain wort prepared with the joint use of an alternative raw material source — buck- wheat and corn, which is widely used in alcohol production, on the metabolic processes of the yeast Saccharomyces cerevisiae 985-T and alcoholic fermentation. The objects of the study were buckwheat and corn; enzyme preparations — sources of amylases, xylanases, β-glucanases and proteases; samples of grain wort, mash and mash distillates. The prospects of introducing mixed grain media prepared using non-traditional buckwheat raw materials into the technology of original alcoholic bever- ages are substantiated. It was shown that the use of buckwheat as a source of biocomplete protein, essential amino acids and minerals together with corn containing a high level of starch and a low level of non-starch polysaccharides contributed both to an increase in the yield of alcohol and a change in the quantitative content of secondary metabolites in the composition of volatile impurities. It was found that an increase in the concentration of soluble carbohydrates in the wort and a decrease in its viscosity by 15.5–40.3% occurred due to the inclusion of corn in the composition of the grain mixture, and the enrichment of the wort with nitrogen assimilated by yeast by 19.0–41.8% — as a result adding buckwheat. The optimal ratio of corn and buckwheat in the composition of the grain mixture (7:3) was selected, which made it possible to improve the biochemical and technological parameters of grain must, increase the efficiency of the vital processes of yeast and alcoholic fermentation, ensure an increase in the yield of alcohol by 1.8%, reduce the formation of side metabolites, especially higher alcohols, and change their composition in the direction of increasing the proportion of aldehydes and esters, which can have a positive effect on the organoleptic characteristics of the distillate.

Getting a Face Brick of Light Shades Based on Marl

The article reflects the topic of the shortage of raw materials for the production of face bricks of light colors. This problem has particularly affected producers in the European part of Russia due to the cessation of clay supplies from the territory of Donbass. Therefore, one of the relevant directions is the search for alternative sources of raw materials. The accumulated experience and laboratory tests have shown the possibility of producing light bricks using marl. As components of the ceramic mass, clays from the Vladimirovsky deposit in the Rostov region of the East Kazakhstan region, charge and marl KO-2 were also accepted from deposits in the Rostov region. By changing the percentage of marl and refractory clay and the firing temperature, it is possible to adjust the color of the fired products, as well as water absorption, average density, strength of products and their shrinkage. Industrial tests conducted on the basis of two brick factories in Rostov-on-Don and the region showed positive results. The use of marl ranged from 40 to 70% of the total weight. Clay from the East Kazakhstan region Vladimirovskoye deposit in the amount of 30 to 60%, respectively, acted as a plastic component. The brick turned out to be light beige to light yellow in color. One of the factories launched the “Svetly” brick into mass production. The material fully meets the requirements of GOST 530–2012. Thus, the problem of the shortage of light clays can be solved by using alternative raw materials – marl. The introduction of 50 to 70% of the mass into the composition is particularly effective. Preliminary calculations show the profitability of the technology by saving raw materials up to 20–25%, while increasing the aesthetic characteristics of the front brick.

A New Alternative Source of Clay Raw Materials for Ceramic Materials Based on the Muddy Deposits in Water-Reservoirs

A New Alternative Source of Clay Raw Materials for Ceramic Materials Based on the Muddy Deposits in Water-Reservoirs

Simulasi Aliran Daya Pada Pembangkitan PLTBG 1 MW Di Laboratorium Teknik Listrik Dengan Koneksi PLN Penyulang RA.01 Rantau Prapat Menggunakan Software Electric Transient And Analysis Program (Etap) 12.6.0

PT Pangkatan Indonesia is an oil palm plantation company operating in Labuhanbatu Regency, North Sumatra Province, with a plantation area of 7,134.8 ha and has built a palm oil mill with an installed capacity of 40 tons / hour. Liquid waste from the plant has the potential to be an alternative source of raw materials for Biogas Power Plants (PLTBg) which is also a distributed generation (DG). The parameters to be studied in this study are the decrease in power losses and the voltage profile of the electrical power produced. The simulation process produces voltage under normal conditions, which only increases about 0.3% of the nominal voltage (complies with Ministerial Regulation No. 4 of 2009). In addition, the results of interconnection analysis at the 1 MW PLTBG show that the voltage at the ends before and after the connection has increased. Furthermore, the ratio of the total current before and after (load 75% - 95% ) is fixed (no change). The conclusion of the results of this study is, the greater the load, the greater the power produced.

Study of the adsorption of copper, nickel and zinc ions on a zeolite-containing sorbent synthesized from thermal power plant waste

The study investigated the possibility of using ash and slag waste from thermal power plants as an alternative raw material source to obtain an inexpensive zeolite-containing sorbent, which was synthesized by hydrothermal synthesis by adding 20% sodium hydroxide at a temperature of 120оC for 24 hours. Using X-ray diffraction, it was established that the synthesized material mainly consists of the framework aluminosilicate mineral hydrosodalite. Using the obtained material, the sorption of copper, zinc, and nickel cations from aqueous media was studied using the Langmuir, Freundlich, and Dubinin-Radushkevich models. The constants of these equations were determined, the values of the isobaric-isothermal potential and the free energy of ion adsorption were calculated. It has been established that the sorption of metal ions is of a physical nature. It was found that the Dubinin–Radushkevich equation better describes the process of adsorption of zinc and nickel, and the Langmuir equation better describes the sorption of copper ions. The decrease in the degree of affinity of sorbed ions to the surface of the synthesized zeolite-containing sorbent was determined as follows: . Thus, based on the obtained values of sorption of copper, zinc, and nickel ions, the fundamental possibility of using ash and slag waste as a raw material source for obtaining inexpensive and effective zeolite-containing sorbents for extracting the above metal ions from aqueous media was established.

CHEMICAL STABILITY OF CELLULOSE NITRATES: REVIEW

The results of the analysis of literature data on updated methods for determining the chemical stability of cellulose nitrates are presented. The relevance of research is due to the need to control the operation and storage of a widespread component of solid rocket fuels and explosive compositions. The criterion for chemical resistance is the value of the decomposition rate or the time dependence of the degree of decomposition of the sample. It is shown that methods for assessing the chemical resistance of cellulose nitrates are based on determining the rate of its thermal decomposition, which is measured by a specific parameter accompanying decomposition. These parameters include weight loss, amount of gaseous decomposition products released, decomposition temperature or thermal effects. Studies are carried out at elevated temperatures and allow you to control the magnitude or rate of change in the parameter that accompanies thermal decomposition. The possibility of using modern analytical methods for evaluating chemical resistance is shown: differential scanning calorimetry, thermogravimetric analysis, chemiluminescent analysis, infrared spectroscopy, high-performance liquid and thin-layer chromatography, gas chromatography, electron paramagnetic resonance, mass spectrometry, X-ray diffraction analysis. The preference for methods of differential scanning calorimetry or differential thermal analysis is substantiated. The results of studies on improving the chemical resistance of cellulose nitrates and compositions based on it with the use of new stabilizers of the aniline series, stabilizers of natural origin with the advantage of the latter on the examples of curcumin and lignins are presented. Due to the insufficient stability of cellulose nitrates, stabilizers added to the formulation of explosive compositions lengthen the induction period of the decomposition of nitro compounds and do not allow the development of the autocatalytic decomposition stage. Methods for determining the chemical stability of cellulose nitrates obtained from alternative sources of raw materials are presented. For citation: Vdovina N.P., Korchagina А.А., Budaev I.А. Chemical stability of cellulose nitrates: Review. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 5. P. 6-20. DOI: 10.6060/ivkkt.20236605.6725.