Losses of gold minerals with fine grades remain an urgent problem of modern flotation technology. Gold minerals associated with iron sulfides (pyrite, arsenopyrite) can be extracted using sulfhydryl collectors. As it is known, the maximum flotability of iron sulfides is observed in case of simultaneous presence on their surface of both xanthate and dixanthogen. The aim of the work is to study the effect of partial oxidation of amyl potassium xanthate (AKs) on the efficiency of flotation enrichment of gold-bearing sulfide ore. Partial oxidation of potassium amyl xanthate solution using turboflotation generator is proposed to obtain a collector including xanthate and dixanthogen in its composition. Testing of collectors AKs and AKs + AKsokisil. on sulfide gold-bearing ore showed that partial oxidation of xanthate to dixanthogen improves technological indicators of flotation. Partial oxidation of xanthate allows to increase gold recovery from 83.8 to 89.3 % at reduction of gold content in flotation tailings from 0.48 to 0.32 g/t. Turboflotation generator allows to increase gold recovery from 89.2 to 91.7 % at reduction of gold content in flotation tailings from 0.31 to 0.24 g/t.
Multilayer Ti3С2Tx MXene was synthesized from Ti3AlC2 MAX phase via hydrofluoric acid etching followed by a gentle shaking-assisted delamination strategy, yielding well-preserved layered structures with expanded interlayer spacing of ~1.2–1.3 nm. Structural and spectroscopic analyses confirmed effective removal of Al layers and the formation of functionalized accordion-like MXene sheets. The electrochemical behavior was systematically investigated in symmetric two-electrode cells using alkaline and acidic electrolytes. The MXene electrode exhibited quasi-rectangular CV curves and symmetric charge–discharge profiles in alkaline media, indicating predominantly capacitive charge storage with good reversibility and rate capability. Significantly higher capacitance and improved retention were obtained in 6 M KOH, reaching ~70–72 F g-1 at low scan rates, which is attributed to enhanced ionic conductivity, reduced charge-transfer resistance, and faster ion diffusion, as further supported by EIS analysis. In contrast, the acidic electrolyte showed distorted CV responses and increased polarization, suggesting slower charge-transfer kinetics and diffusion limitations. These findings highlight the decisive role of electrolyte chemistry in governing charge-storage mechanisms and demonstrate the strong potential of multilayer Ti3С2Tx MXene for supercapacitor applications in concentrated alkaline electrolytes.
The dearomatization, denitrification and oxidative desulfurization of commercial diesel fuels were investigated using glycerol-based deep eutectic solvents. The optimal conditions of liquid-liquid extraction processes were chosen as room and 90°C temperatures and 3 hours of mixing time. Ammonium chloride-glycerol, triethylammonium acetate-glycerol and choline chloride-glycerol were used as extractive solvents in the purification processes. Diesel-Deep eutectic solvents (Diesel-DESs) were taken as the volume ratios of 1:1 for the dearomatization and denitrification processes. The volume ratios of Diesel-DESs-H2O2 were 1:1:2 for the oxidative desulfurization. H2O2 was selected as the oxidative agent of oxidation desulfurization. Before and after separation processes, the exploitation properties were studied by ASTM standards and compared to commercial diesel. All separation processes were controlled by gas chromatography and 1H NMR methods. Based on the NMR analysis, NH4Cl/6Glycerol with H₂O₂ and ChCl/6Glycerol were the most effective extractive agents for purified diesel samples, from the alkyl aromatic, naphthenic, and heteroatomic compounds.
The widespread adoption of electric transportation is leading to the accumulation of spent lithium-ion batteries requiring sorting prior to recycling or reuse. Effective triage of end-of-life (EoL) batteries necessitates rapid non-destructive diagnostic methods capable of assessing the state of health at the individual cell level. This study proposes an approach to rapid diagnostics based on electrochemical impedance spectroscopy. Using a 10S6P battery pack from an electric scooter operated under sharply continental climate conditions as an example, we demonstrate that equivalent circuit model parameters – including ohmic resistance, charge transfer resistance, and constant phase element exponents – enable the identification of intra-pack degradation heterogeneity and classification of cells according to their suitability for reuse. Analysis revealed two distinct degradation patterns: localized critical discharge attributed to battery management system malfunction, and a gradient of accelerated aging in peripheral cells due to thermocyclic stress. It was established that 80% of the cells in the investigated pack retain characteristics permitting second-life applications, while 10% exhibit signs of irreversible degradation and require immediate recycling. The results confirm the promise of impedance spectroscopy as a tool for high-throughput triage of EoL batteries within the circular economy framework.
Manganites-perovskites are an important class of materials with unique physical properties such as tremendous magnetoresistance and magnetocaloric effect. They have a perovskite structure and can be described by the general formula AMnO₃, where A is a rare earth or alkali metal and Mn is manganese. The introduction of dopants into the composition of rare-earth element manganite can serve as an effective way to improve the properties of semiconductors. The aim of this work is the synthesis and X-ray diffraction study of a new nickelite-manganite of neodymium and magnesium of the composition NdMg2NiMnO6. A new nickelite-manganite of neodymium and magnesium composition NdMg2NiMnO6 was synthesized by the method of ceramic technology. The identification was carried out by XRD method. On the basis of indication it was found that NdMg2NiMnO6 crystallizes in cubic syngony with the following lattice parameters: a=10.056 ± 0.067 Å; Z=4; Vo=4139.39 ± 0.20 Å3; Vounit cell.=1034.85 ± 0.02 Å3, rх-ray.=2.5824; rpycn. =2.4970 ± 0.052 g/cm3. The tolerance factor t=0.90, which is a criterion of structure stability, was calculated. IR spectra of the investigated nickelite-manganite were obtained. The obtained results are of interest for further work on the study of thermodynamic, electrophysical properties of this compound and can be used in inorganic materials science to obtain similar substances with promising physical and chemical properties, and as initial information arrays for loading into fundamental data banks on X-ray characteristics.
В настоящем исследовании впервые синтезированы флуоресцентно-меченые образцы хитозана и полиакриловой кислоты (ПАК) для изучения глубины проникновения в лесную почву полимеров и интерполиэлектролитного комплекса (ИПЭК) и их устойчивости к вымыванию. Cинтез флуоресцентно-меченых полимеров и ИПЭК проводился методом смешения растворов c применением флуоресцеин изотиоцианата (FITC) и флуоресцеинамина (FA). Для идентификации состава и определения структуры синтезированных продуктов использовали ИК-cпектроскопию. Оптимальный мольный состав полученного ИПЭК [Хитозан]:[ПАК] = [1:9] подтвержден методом гравиметрии. Реовизкозиметрическим методом установили псевдопластичное течение хитозана и дилатантное течение ПАК и ИПЭК. В условиях лабораторных модельных опытов изучены механическая прочность и противоэрозионная устойчивость почвенно-полимерных структуратов. Обработка почвы ИПЭК способствовала формированию защитной почвенно-полимерной пленки, которая значительно повышает устойчивость почвенной поверхности к ветровой эрозии до 93% и к водной эрозии до 90%, а также усиливает механическую прочность почвенных агрегатов в 13 раз. Исследование подтверждает наибольшую устойчивость к вымыванию ИПЭК в отличие от индивидуальных полимеров, что представляет важное значение для практики структурирования и стабилизации почв в условиях эрозии.
Driven by the growing threat of antimicrobial resistance, the search for novel antibacterial agents has identified decahydroquinoline derivatives as promising structural scaffolds. The aim of this work was a comparative study of the synthetic reactivity of two decahydroquinolone isomers and the subsequent antimicrobial activity of their N-cyanoethylated products. The target compounds were synthesized via an aza-Michael addition, wherein the influence of stereochemistry on reactivity was investigated, and a Cu(OAc)₂ catalyst was optimized for the sterically hindered isomer. Antimicrobial activity was assessed by the broth microdilution method, while cytotoxicity was evaluated using an MTT assay on the MDCK kidney cell line. It was established that the position of the methyl group within the decahydroquinoline core is a critical determinant of both the steric accessibility for N-cyanoethylation and the resulting biological activity. The N-(β’-cyanoethyl)-2a-methyldecahydroquinolin-4-one exhibited selective bactericidal activity against the Gram-positive strain Staphylococcus aureus (MBC = 5 mg/mL), whereas its 10-methyl substituted analogue was completely inactive. Importantly, the active compound demonstrated low cytotoxicity (CTC₅₀ > 0.8 mg/mL), indicating a favorable selectivity profile. These findings identify the 2a-methyldecahydroquinolin-4-one fragment as a promising scaffold for the rational design of new selective antibacterial agents.
The use of lithium metal as an anode in lithium-metal batteries is desired due to its high capacity and highly negative potential but is still not achieved due to the high activity and consequent chemical and electrochemical instability of this metal. On contact with the electrolyte, a film (SEI) is formed on the lithium surface consisting of the electrolyte decomposition products. Typically, this film has a heterogeneous structure, making it unstable and it cracks during cycling, which leads to lithium local deposition in the form of outgrowths – dendrites. A short circuit can occur when the dendrites grow to the cathode, followed by a possible battery fire. To solve this problem, it was proposed to coat lithium anodes with artificial SEI with the desired properties: homogeneous structure, high ionic and low electronic conductivity, and mechanical and chemical stability. The main methods for applying such coatings are dipping, dripping, doctor blade smearing, chemical or electrochemical reaction with lithium, and techniques such as magnetron sputtering, atomic and molecular layer deposition, and plasma activation. In this review examples of artificial protective coatings of different nature on lithium, their structure and functional features are considered. The reasons for their enhancement of lithium-metal anode operation stability and the characteristics obtained as a result of anode protection by these films are also indicated. At comparison of various approaches to creation of artificial SEI the methodological problem on an estimation of their efficiency is revealed and the decision variant is offered.
В последние два десятилетия в научной литературе широко освещаются вопросы использования просроченных лекарственных препаратов для антикоррозионной защиты металлов. Целью данной работы является исследование просроченного лекарства Дротаверин (Но-шпа) в качестве ингибитора коррозии углеродистой стали Ст3 в 1 М растворе НСl. Концентрация Дротаверина варьировала в пределах 20-80 мг/л. Исследования проведены методами гравиметрии, потенциодинамической поляризации, импедансной спектроскопии, сканирующей электронной микроскопии. Гравиметрические исследования ингибирующего действия Дротаверина проведены при комнатной температуре в течение 2 и 24 ч и при 80°С в течение 0,5 ч с защитным эффектом (Z, %) 72, 82 и 96 %, соответственно, при концентрации 80 мг/л. Рассчитанные по поляризационным и импедансным измерениям величины Z близки к определенным гравиметрически. Оценены степени заполнения поверхности электрода ингибитором и показано подчинение адсорбции Дротаверина изотерме Ленгмюра. Рассчитанная свободная энергия адсорбции, равная -29 кДж/моль, свидетельствует о физической адсорбции препарата на поверхности стали с некоторой долей хемосорбции. Дротаверин вызывает замедление катодной и анодной электродных реакций.
В настоящей работе исследовано взаимодействие тетрабутиламмониевых солей анионов [B10H10]2- и [B12H12]2- с тетрагидрофураном, 1,4-диоксаном и тетрагидропираном в присутствии водных растворов H[BF4] и H2[SiF6]. Показано, что в результате данных реакций с высокими выходами образуются монозамещенные производные клозо-декаборатного аниона ([2-B10H9O(CH2)4]-, [2-B10H9O(CH2)4О]-, [2-B10H9O(CH2)5]-) и клозо-додекаборатного анионов ([B12H11O(CH2)4]-, [B12H11O(CH2)4О]-, [B12H11O(CH2)5]-). Доказано, что в случае аниона [B10H10]2- взаимодействие протекает региоселективно и приводит именно к продукту с заместителем в экваториальном поясе борного кластера. Производное клозо-додекаборатного аниона с экзо-полиэдрическим тетрагидропирановым заместителем было далее функционализировано за счет реакции с цианидом калия в среде ДМФА. Исследования показали, что в результате происходит раскрытие циклического заместителя с образованием производного, содержащего пендантную циано-группу, присоединенную к борному кластеру через пентаметиленовый спейсер. Данное соединение может быть далее модифицировано за счет концевой группы с целью получения биологически активных борсодержащих производных, перспективных для применения в 10В-нейтронозахватной терапии злокачественных опухолей, а также антимикробной и противовирусной терапии. Строение всех полученных производных было подтверждено с помощью комплекса современных физических и физико-химических методов анализа (элементный анализ, ИК-спектроскопия, мультиядерная ЯМР-спектроскопия, ESI масс-спектрометрия).
В работе рассмотрены особенности технологии получения гранулированного активированного угля из некондиционных мелкозернистых углеродных фракций, являющихся отходом промышленного производства спецкокса АО «Шубарколь комир». Разработана технологическая схема получения активированного угля на основе отходов промышленного производства спецкокса, включая методы и режимы грануляции, карбонизации и активации. Проведена оценка физико-химических характеристик и структуры полученных целевых углеродных материалов.Получены гранулированные и порошковые активированные угли на основе коксовой мелочи с составом: 60% коксовая мелочь, 35% связующее вещество, 5% химический активирующий агент. Определены температурные зависимости процесса активации. Методами адсорбционно-структурного анализа изучена структура активированного угля, показано наличие развитой пористой структуры, включающей мезопоры с размером щелей от 2 до 32 нм.
В работе изучена возможность получения активированных углей из малоликвидных фракций карбонизованных материалов коксохимического производства АО «Шубарколь комир» (г. Караганда). Для получения угольного сорбента коксовую мелочь размером ≤ 10 мм измельчали и просеивали, получая фракцию 2–5 мм. Полученную фракцию активировали на опытной установке в присутствии углекислого газа при температурах 700-900°C и времени активации 60-180 мин. Установлено, что максимальная сорбционная способность достигается при температуре 800°C и времени активации 180 мин. При этих условиях достигается максимальная сорбционная ёмкость по йоду (56,73%) и метиленовому голубому (100 мг/г). С помощью метода низкотемпературной адсорбции азота по методу БЭТ (Брунауэра, Эммета и Теллера) определена удельная поверхность сорбента, которая составила 446,8±4,4 м2/г. Анализ адсорбционной и десорбционной ветвей изотермы указывает на мезопористую структуру полученных сорбентов. Исследование состава отходящих газов показало наличие водорода, оксида углерода, диоксида углерода и азота. Анализ газового состава отходящих продуктов активации выявил значительное содержание CO (51,52%), что свидетельствует о глубокой термической модификации коксовой мелочи в процессе активации углекислым газом CO2.
The temperature dependence of the heat capacity of lanthanum and lithium zirconmanganite LаLi2ZrMnO6 was studied by the method of experimental dynamic calorimetry in the range of 298.15- 673 K. On the curve of the dependence Ср°~f(Т) at 348 K, a λ-shaped effect wasrevealed, probably related to a type II phase transition. Taking into account the temperature of the phase transition, the equations of the temperature dependence of the heat capacity of zirconmanganite are derived. The calculated value of the standard heat capacity of lanthanum and lithium zircono-manganite is in satisfactory agreement with experimental data within the error limits of experimental and computational methods. The standard entropy of the investigated zircono-manganites is calculated by the method of ion increments. In the range 298.15-673 K, the temperature dependences Ср°(Т) and the thermodynamic functions S°(T), H°(T)-H°(298.15) and Fxx(Т) were calculated. According to the developed methodology, the fundamental thermodynamic constant, the standard enthalpy of formation of zircono-manganite LаLi2ZrMnO6,was calculated.
The study focuses on the synthesis and pharmacological evaluation of novel structural analogs of the anesthetic and antiarrhythmic Kazcaine. Two new derivatives were synthesized by acylation of propylacetylene alcohol 1-(2-ethoxyethyl)-4-oxopiperidine with fluorobenzoyl chlorides. Their complexes with cyclodextrin were obtained for biological screening. The evaluation of the myelostimulating activity of these complexes revealed that one of them, specifically the 3-fluorobenzoyloxy derivative, demonstrated a pronounced myelostimulating effect, particularly with regard to the stimulation of leukopoiesis and thrombopoiesis. The compound, in complex with (3-cyclodextrin, showed significant stimulation of leukocyte and platelet proliferation, with a noticeable increase in the total number of leukocytes and improvement in granulocyte and lymphocyte recovery. These results indicate that the synthesized compounds have significant potential for pharmacological use, especially for stimulating hematopoiesis and protecting against myelosuppression. In addition, quantum chemical calculations of the reactions showed that ortho-and meta-fluorobenzoyl chloride have higher reactivity, which is confirmed by the high yields of the products (94% and 89%) obtained as a result of the synthesis.
The possibility of obtaining activated carbons from low-liquid fractions of carbonized materials from the coke chemical production of JSC "Shubarkol Komir" (Karaganda) has been studied. To obtain a coal sorbent, coke fines with a size of less than 10mm were crushed and sieved to obtain a fraction of 2-5mm. The resulting fraction was activated on a pilot plant in the presence of carbon dioxide at temperatures of 700-900 degrees C and an activation time of 60-180 min. It was found that the maximum sorption capacity is achieved at a temperature of 800 degrees C and an activation time of 180 min. Under these conditions, the maximum sorption capacity for iodine (56.73%) and methylene blue (100mg/g) is achieved. Using the method of low-temperature nitrogen adsorption using the BET method, the specific surface area of the sorbent was determined, which was 446.8 +/- 4.4 m2/g. The analysis of the adsorption and desorption branches of the isotherm indicated the mesoporous structure of the obtained sorbents. The study of the exhaust gas composition showed the presence of hydrogen, carbon monoxide, carbon dioxide and nitrogen. An analysis of the gas composition of the waste activation products revealed a significant CO content (51.52%), which indicates a deep thermal modification of coke fines during activation by carbon dioxide CO2.
The temperature dependence of the heat capacity of lanthanum and lithium zirconmanganite LaLi2ZrMnO6 was studied by the method of experimental dynamic calorimetry in the range of 298.15-673 K. On the curve of the dependence Cp degrees similar to(T) at 348 K, a lambda-shaped effect was revealed, probably related to a type II phase transition. Taking into account the temperature of the phase transition, the equations of the temperature dependence of the heat capacity of zirconmanganite are derived. The calculated value of the standard heat capacity of lanthanum and lithium zircono-manganite is in satisfactory agreement with experimental data within the error limits of experimental and computational methods. The standard entropy of the investigated zircono-manganites is calculated by the method of ion increments. In the range 298.15-673 K, the temperature dependences Cp degrees(T) and the thermodynamic functions S degrees(T), H degrees(T)-H degrees(298.15) and Fxx(T) were calculated. According to the developed methodology, the fundamental thermodynamic constant, the standard enthalpy of formation of zircono-manganite LaLi2ZrMnO6, was calculated.
The basic therapy for microbial infections involves the application of antibiotics. However, overuse of antibiotics has become the major factor for the emergence and dissemination of multi-drug resistant strains. The purpose of our work was to study the phytochemical composition of a thick extract of raspberry fruits, as well as to investigate in vitro and in silico antibacterial activity against clinical multidrug-resistant strains of A. baumannii, P. aeruginosa, K. pneumoniae and E. cloacae. The quantification of biologically active substances (BAS) was accomplished with spectrophotometric, titrimetric and HPLC methods of analysis; antimicrobial effects were evaluated by the well diffusion method, whereas minimum inhibition concentration was determined by well plate method. The total content of phenolic compounds was 0.60 and 10.10%, organic acids-4.60 and 1.60% for raspberry fruit thick and green tea leaf extract. The total content of anthocyanins in the raspberry fruit thick extract was 110.0 mg/100 g, where cyanidin-3-O-sophoroside was dominated (52.14 +/- 1.04 mg/100 g). Theoretical studies have shown that neither a single antibiotic nor anthocyanins are highly effective in inhibiting all antimicrobial mechanisms of resistant Gram-negative bacteria. The thick raspberry fruit extract actively inhibits all resistant strains of A. baumannii, K. pneumoniae, P. aeruginosa and E. cloacae. These findings have shown that to inhibit resistant strains of bacteria, you need to use only a complex drug or dietary supplements of raspberry together, and in turn, herbal medicines are a "lifeline" for their creation and there is a chance of old antimicrobial drugs back in life.
In the last two decades, the scientific literature has widely covered the use of expired medicinal preparations for anticorrosion protection of metals. The aim of this work is to study expired Drotaverine (No-shpa) as a corrosion inhibitor for St3 carbon steel in a 1 M HCl solution. Drotaverine concentrations ranged from 20-80 mg/L. Studies were conducted using gravimetry, potentiodynamic polarization, impedance spectroscopy, and scanning electron microscopy. Gravimetric studies of Drotaverine's inhibitory effect were carried out at room temperature for 2 and 24 hours, and at 80 degrees C for 0.5 hours, showing a protective effect (Z, %) of 72, 82, and 96%, respectively, at a concentration of 80 mg/L. The Z values calculated from polarization and impedance measurements were close to those determined gravimetrically. The surface coverage of the electrode by the inhibitor was estimated, and it was shown that Drotaverine adsorption conforms to the Langmuir isotherm. The calculated free energy of adsorption, equal to-29 kJ/mol, indicates physical adsorption of the drug on the steel surface with some contribution from chemisorption. Drotaverine causes a deceleration of both cathodic and anodic electrode reactions.
This work investigates the reaction of tetrabutylammonium salts of [B10H10](2-) and [B12H12](2-) anions with tetrahydrofuran, 1,4-dioxane, and tetrahydropyran in the presence of aqueous H[BF4] and H-2[SiF6] solutions. It is shown that these reactions yield mono-substituted derivatives of the closo-decaborate anion ([2-B10H9O(CH2)(4)](-), [2-B10H9O(CH2)(4)O](-), [2-B10H9O(CH2)(5)](-)) and closo-dodecaborate anion ([B12H11O(CH2)(4)](-), [B12H11O(CH2)(4)O](-), [B12H11O(CH2)(5)](-)) in high yields. It was proven that in the case of the [B10H10](2-) anion, the reaction proceeds regioselectively, leading specifically to products with substituents in the equatorial belt of the boron cluster. The closo-dodecaborate anion derivative with an exo-polyhedral tetrahydropyran substituent was further functionalized by reaction with potassium cyanide in DMF. Studies showed that this reaction results in the opening of the cyclic substituent, forming a derivative containing a pendant cyano group attached to the boron cluster via a pentamethylene spacer. This compound can be further modified at the terminal group to obtain biologically active boron-containing derivatives, promising for use in B-10-neutron capture therapy (BNCT) of malignant tumors, as well as antimicrobial and antiviral therapy. The structures of all obtained derivatives were confirmed using a comprehensive set of modern physical and physicochemical analytical methods (elemental analysis, IR spectroscopy, multinuclear NMR spectroscopy, ESI mass spectrometry).
This study examines the specific features of the production technology of granular activated carbon obtained from substandard fine-grained carbon fractions, which are by-products of the special coke industrial production at JSC Shubarkol Komir. A technological scheme was developed for producing activated carbon based on this industrial waste, including the methods and conditions for granulation, carbonization, and activation. The physicochemical properties and structural characteristics of the resulting target carbon materials were evaluated. Granular and powdered activated carbons were produced from coke fines with the following composition: 60% coke fines, 35% binder, and 5% chemical activating agent. The temperature dependencies of the activation process were determined. Using adsorption-structural analysis methods, the structure of the activated carbon was studied, revealing a well-developed porous structure that includes mesopores with slit sizes ranging from 2 to 32 nm.
