This study explores the synthesis of activated biochar (ABC) from date pits and CuO-ABC nanocomposite for the adsorption elimination (AE) of model and commercial fuels. Outcomes deduced from FESEM, TEM, EDX, XRD, and the N2 adsorption-desorption isotherms confirmed the microporous structures of both adsorbents. The SABET as well as pore diameter of the ABC were, respectively, 765.52 m2/g and 1.79 nm, while the SABET and pore diameter of CuO-ABC nanocomposite were, respectively, 621.57 m2/g and 1.99 nm, referring to the micro-porous structures of both adsorbents. The maximum AE % of 200 mg/L DBT solution by the ABC was 98.09 % using 0.20 g of the ABC at 30 degrees C for 25 min. In comparison, the highest AE % of 200 mg/L DBT solution over the CuO-ABC nanocomposite was 99.24 %, achieved with 0.15 g of nanocomposite at 30 degrees C for 20 min. The isothermal and kinetic studies revealed that the Langmuir adsorption isotherm and the pseudo-2nd-order kinetic model best described the adsorption of DBT. Both adsorbents exhibited sustained activity across five consecutive cycles. The S-content of real gasoline was reduced to 80.12 % and 84.22 % using 0.60 g of both adsorbents at 30 degrees C for 120 min. This work presents cost-efficient adsorbents for desulfurization of a model desulfurization system and actual fuel oils at the industrial scale.
The purpose of this study was to investigate the influence of electron vacancies on the superconducting properties of transition metal sulfide compounds (Cr, Cu) to evaluate their potential in increasing the critical transition temperature. This study reviewed the theoretical models and experimental data on superconductivity based on copper, chromium, and sulfide compounds. Synthesis and stability data for the FeCuS2 compound were used for analysis, and temperature coefficients for various superconducting materials, including oxides and sulfides, were calculated. The study considered the compound Fe2Cu3S6, which exhibited superconductivity at 89 K, with a narrow transition interval and evidence of ferromagnetic ordering. Experimental data indicated the influence of electron vacancies in the crystal lattice on conductivity, which favors the occurrence of the superconducting state. Model calculations revealed a linear dependence between the number of electron vacancies Qelv and the transition temperature Tc in a series of sulfide systems, including Cr-Cu-S. This gives prospects for the search for superconductors with high transition temperatures. Comparison with other materials, such as oxide compounds, revealed that sulfides can exhibit greater critical superconductivity temperatures. The practical significance of the study lies in the development of new approaches to the design of sulfide compounds that promote the generation of a superconducting state at room temperatures.
We report the fabrication of catalytically active AgNPs/Cu oxygen reduction cathodes using the method of galvanic replacement of copper with silver in K[Ag(CN)(2)] solutions. It was shown that the formed AgNPs with an average size < 50 nm are uniformly distributed on the copper surface, and their content depends on the concentration of the cyanocomplex and the duration of the GR process. It was determined that in a broad silver concentration range (0.02-0.86 at. %) on the copper surface, the AgNPs/Cu cathodes exhibit 15 % higher ORR activity than silver cathodes, and exhibit superior parameters E-onset (by similar to 0.02 V) and E-1/2 (by similar to 0.05 V). The testing results in alkaline zinc-air fuel cells showed that the discharge voltage of cells based on AgNPs/Cu cathodes rivals that of the cells based on silver cathodes.
The present study investigates the relevance of producing fluorine-containing polymers based on tetrafluoroethylene (TFE) and TFE-hexafluoropropylene (HFP) compositions. It has been demonstrated that the byproducts resulting from the degradation of these polymers are hazardous, and their recycling or disposal is challenging. A thorough analysis of contemporary methods of polytetrafluoroethylene (PTFE) recycling has been conducted, indicating that chemical processing of PTFE results in the generation of substantial quantities of monomers, including TFE, HFP, and cyclooctafluorobutene. These monomers can be utilized in the synthesis of new fluoropolymers, contingent upon the assurance of sufficient purity. The article puts forward a novel absorption-based method for the purification of HFP and TFE from fluorinated hydrocarbon compounds. It has been established that ethyl acetate (EA) is a selective solvent for TFE, HFP, and the associated fluorinated hydrocarbons. The solubility of all components of the gas mixture in EA was investigated within the temperature range of 263-313 K. An analysis was conducted on the temperature dependence of Henry's law constant during dissolution, the results of which indicated an increase in the solubility of fluorinated organic gases in EA with an increase in temperature. The parameters of the absorption purification process for perfluoromonomers were determined, thereby enabling the reduction of fluorinated hydrocarbon compounds by two orders of magnitude and yielding monomer products with a main substance content of no less than 99.99 vol. %.
This article presents the results of a comprehensive study on the chemical composition and antioxidant activity of aqueous-ethanolic extracts obtained from Persea americana Mill. (avocado) seeds using extractants of different concentrations (40 % and 70 %) and raw materials in different states (fresh and dry). Thin-layer chromatography confirmed the presence of ascorbic acid as well as phenolic compounds in all extracts, including gallic acid and quercetin. The total phenolic content was determined spectrophotometrically using the Folin-Ciocalteu method, while the total flavonoid content was measured by the aluminum chloride colorimetric assay based on a linear regression equation derived from the quercetin calibration curve (expressed in QE). Quantitative analysis showed that the total phenolic content ranged from 1.204 to 1.861 mg/g, flavonoids-from 2.663 to 3.395 mg/g, and amino acids (determined by the ninhydrin reaction)-from 0.054 to 0.140 % in terms of alanine equivalent. The highest phenolic content was found in the 40 % extract from dry seeds, whereas flavonoids were more efficiently extracted with 40 % ethanol from fresh raw materials. Modeling of lipid peroxidation and protein oxidative modification processes in vitro revealed pronounced antioxidant activity in all extracts, particularly in the 40 % extracts from dry seeds, which reduced the levels of thiobarbituric acid-reactive substances by 44.3 % and protein carbonyl groups by 73.1 % (p <= 0.001). These findings indicate the high antioxidant potential of Persea americana seeds, suggesting their promise as a natural source of antioxidants for pharmaceutical, cosmetic, and food applications.
Research on the exploration of active compounds from Sacha Inchi (SI) seeds, Pluketenia volubilis L., has been conducted. The study aimed to profile the secondary metabolites of SI seeds using liquid chromatography-orbitrap high-resolution mass spectrometry (LC-Orbitrap HRMS), screen for chemical compounds, determine total phenolic and flavonoid contents, and assess antibacterial activity. The antibacterial assay included inhibition zone measurement, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). The results revealed that the acetone extract of SI seeds contains steroid/triterpenoids, alkaloids, and flavonoids. According to LC-Orbitrap HRMS data, 41 steroids, 20 alkaloids, and one flavonoid were identified in the acetone extract. Neriifolin, Dehydrated antipain, and Artoindonesianin B were the predominant steroid, alkaloid, and flavonoid, respectively, representing the novelty of this research. The acetone extract of SI seeds exhibited a total phenolic content (TPC) of 28.04 +/- 1.40 mg GAE/g and a total flavonoid content (TFC) of 25.98 +/- +/- 1.40 mg QE/g. The acetone extract of SI seeds was fractionated with several solvents and tested for antibacterial activity. SI seed extract inhibited Staphylococcus epidermidis ATCC 25923, Staphylococcus aureus ATCC 12228, and Methicillin-resistant Staphylococcus aureus (MRSA). The chloroform fraction demonstrated the strongest inhibition against MRSA, with an inhibition zone of 16.4 +/- 0.4 mm (strong), MIC 3.125 mg/mL, and MBC 25 mg/mL, while the n-hexane fraction showed the strongest activity against S. aureus (15.7 +/- 0.3 mm (strong), MIC 3.125 mg/mL, MBC 6.25 mg/mL) and S. epidermidis (10.5 +/- 0.3 mm (strong), MIC 3.125 mg/mL, MBC 25 mg/mL). This study provides a solid foundation for future research, particularly on the secondary metabolites of SI seeds as antibacterial candidates.
Aluminum alloys are widely used in the automotive and aeronautical industries due to their good mechanical properties, high corrosion resistance, and low weight. In this study, an aluminum-based medium-entropy alloy was fabricated by adding copper and silver. The alloy composition consisted of 97 wt.% aluminum, with 1.5 wt.% copper and 1.5 wt.% silver. The processing technique was carried out using the powder metallurgical route. After the sintering phase, different thermal aging treatments were conducted to improve the aluminum alloy's mechanical properties. Heat treatments were performed at different times and temperatures. The results revealed a microstructure with very fine grain sizes, consisting of two phases: an alpha-solid solution matrix with a composition close to the nominal alloy, and an intermetallic beta-phase composed of dispersed, copper-rich AlCuAg precipitates.
A literature review of modern chemical methods for modifying road bitumen has been conducted, focusing on their popularity and the nature of their impact on binder properties. Sulfur, polyphosphoric acid, maleic anhydride, thermosetting resins (such as phenol-formaldehyde, epoxy, polyester, etc.), and polymers are the most commonly used chemical modifiers in road construction practices. The method of producing bituminous materials with varying penetration levels through the chemical modification of oil residues with formaldehyde has been considered. All bituminous materials produced via chemical modification demonstrate better homogeneity during high-temperature storage compared to those modified through physical methods due to the chemical interaction between a reactive modifier and bitumen. It has also been shown that chemical modifiers are often used in combination with physical modifiers to enhance their effectiveness.
This review outlines the main approaches to developing the energy recovery processes from leather waste. It discusses the challenges and opportunities for accelerating the utilization of solid leather waste for biofuel production and considers promising methods for processing biomass, chromium waste, sewage sludge, and fat into bioenergy feedstocks.
2-Aminothiazole and compounds with terminal phenoxy groups are privileged structures in medicinal chemistry. Compounds containing these two scaffolds are of interest for the design of new pharmaceuticals, particularly for treating malignant tumors. Hybridization, which is realized by combining both privileged fragments via the formation of covalent bonds, is a promising approach to finding lead compounds. The resulting conjugates can bind to a variety of receptors, and therefore, their synthesis and pharmacological screening is an actual task of modern medicinal chemistry. This review highlights the latest advances in the field of phenoxyalkylacylamino thiazoles and their analogs with anticancer potential, covering work published over the past two decades.
The increased utilization of lignite in "green" technologies represents a critical step toward the rational use and valorization of low-grade fossil fuels. This study examines the current state of lignite deposits in Ukraine and explores its potential applications in non-energy and environmentally sustainable energy sectors. The chemical composition of humic acids derived from brown coal was analyzed, along with their ability to undergo hybrid modification with biodegradable materials such as hydrogels, biofilms, and composites. The potential of lignite-based humic acids as sorbents for the removal of heavy metals from wastewater was evaluated, highlighting their role in ecological remediation. Special attention was given to the process of low-temperature gasification of lignite for the production of additives to polymer-modified bitumen. The results confirm the feasibility of developing innovative lignite processing methods in accordance with the principles of "green" technologies.
Functionalization of organic semiconductors with fluorine atoms and fluorine-containing groups can give rise to a wide variety of properties, for example, increase the rate of electron transport, induce harvesting of non-emissive triplet excitons through thermally activated delayed fluorescence (TADF) or room temperature phosphorescence (RTP), improve photoluminescence quantum yield (PLQY) by forming multiple intra- and intermolecular interactions, and increase solution-processabitily of the compounds, therefore, lowering the cost of device fabrication. Diverse synthetic approaches have been implemented to afford fluorinated organic semiconductors. In this review, we discuss some of the recent and most interesting organic semiconductors with C–F and C–CF3 bonds as well as their application.
Heterogenization of catalysts offers numerous advantages over homogeneous systems, including enhanced stability, reusability, and fine-tuning of properties. This approach is particularly relevant for developing environmentally friendly and sustainable catalytic processes. Microgels, with their unique properties, emerge as promising platforms for catalyst heterogenization. These crosslinked polymer networks exhibit tunable size, porosity, and responsiveness to external stimuli, making them ideal for encapsulating and stabilizing catalytic species. The integration of Se-containing functional groups into the microgel structure further enhances their catalytic potential, leveraging the redox properties of selenium for oxidation reactions. This bioinspired approach offers a novel route for catalyst design and contributes to the development of environmentally friendly and efficient processes.
The article analyzes the current understanding of the influence of coke quality on the ironmaking process. The requirements for its metallurgical characteristics are formulated. One of the main factors affecting the possibility of efficient operation of blast furnaces is the quality of coke. This quality significantly depends on the quality of coal raw materials, methods of coal batch preparation, and methods of its pretreatment. To ensure the efficiency and cost-effectiveness of coke production and expand the raw material base of coking coal, it is necessary to use scientifically sound, economically feasible approaches to the introduction of advanced technologies, such as frontal coal cleaning, prediction, and optimization of the batch composition taking into account the petrographic characteristics of its components and the expansion pressure of coal concentrates, modification of the batch using additives, rational preparation of coal by crushing, and coking of stamped batches. A comparison of coke quality prediction methods used in the testing of coal batches is presented. The main methods of improving coal and coal batch preparation (including those implemented at coke plants in Ukraine) are described. Research that was not available to the English-speaking reader is analyzed.
Wax deposits create significant obstacles to the flow of crude oil, as they cause pressure anomalies in the pipeline, reduce its passage diameter, and lead to artificial blockages. For two types of oil from the Dolinske and Borislavske fields (the western region of Ukraine), the amount of deposits was determined using the Cold Finger method. The dynamics of the growth in the deposit amount within a time up to 24 hours were shown. The effectiveness of the Dodiflow 5236 pour point depressant as a wax deposition inhibitor was evaluated. It was found that the depressant reduces the amount of deposits formed by 1.5-2.5 times. In addition, the depressant reduces the rate of wax deposition and changes the structure of crystals. It was shown that the amount of deposits formed from crude oil and oil with a depressant depends not only on the physicochemical characteristics of the oil, but also on the temperature difference between the oil and the wall.
The effect of metal silicides, TiSi2, VSi2, MoSi2, HfSi2, TaSi2, and WSi2, on the initial stages of the liquidphase oxidation processes of 1,7-octadiene by molecular oxygen was investigated. It was established that the presence of a homogeneous initiator of radical processes, tert-butyl hydroperoxide, was necessary for the oxidation reaction to proceed. VSi(2 )is the best catalyst for the oxidation of 1,7-octadiene by O-2. VSi2 and MoSi2 exhibited excellent reusability over five cycles of use without significant loss in their catalytic activity. VSi2 and MoSi2 before and after the oxidation reaction were characterized by XRD and FTIR.
Materials based on polylactide 3D matrices with their subsequent filling with modified epoxy resin were developed. Their elastoplastic, deformation, and strength characteristics were investigated. It was found that the filling plane of the studied products significantly affects the values of deformation and hardness. The introduction of epoxidized soybean oil into the composition improves the impact strength of the composites, increasing the flexibility of the material and increasing its ability to absorb and dissipate energy under impact loads. The combined composites are characterised by increased flexural strength, tensile strength, and flexural strain.
The critical need for the restoration of the human musculoskeletal system, damaged due to osteoporosis, blast injuries, and congenital anomalies, has been identified. The needs of regenerative medicine aimed at the maximum possible restoration of the structure and functions of damaged tissues have been outlined. The necessity for the development of bioactive materials to substitute long bone defects through the creation of glass-ceramic materials with high biological activity and mechanical strength has been established. High-strength glass-ceramic materials have been developed through rapid low-temperature thermal treatment. These materials are characterized by the presence of bioactive phases such as hydroxyapatite and lithium phosphate, spodumene, eucryptite, diopside, and lithium disilicate. They can withstand significant mechanical (compressive strength 550-650 MPa, bending strength 350-450 MPa, fracture toughness 4.5-6.1 MPa & centerdot;m0.5) and thermal (CTE = (40.5-79.2)& centerdot;10(-7)degrees & Scy;(-1)) loads and are promising candidates for use as substitutes for bone tissue in long bone elements.
In this study, fly ash (FA)-based geopolymers were synthesized using varying proportions of sodium silicate/sodium hydroxide (Na2SiO3/ NaOH 10M) solution, ranging from 49% in the 51FA sample to 67% in the 33FA sample, used for the adsorption of methylene blue (MB) in water. Following curing at 60 degrees C for 24 h, the porosity of the resulting geopolymers decreased, attributed to the enhanced polycondensation process driven by the increased Na2SiO3 content, which resulted in the formation of a more compact gel structure in the obtained geopolymer. The Weber-Morris model indicated that surface interactions with MB molecules were predominant in the 51FA sample, while pore-filling mechanisms were more pronounced in the 33FA geopolymer. Adsorption experiments revealed that all geopolymer samples conformed to the Langmuir isotherm model, with correlation coefficients approaching unity.
Present research aimed to develop a method for synthesizing long-chain alcohol esters of fatty acids in high product yields and low excess of alcohol using available components and a catalyst. All samples were obtained under similar conditions: the molar ratio of the fatty acid and the corresponding alcohol was 1/1.1 mol/mol using ptoluenesulfonic acid as a catalyst. The cyclohexane was used to remove water. The esterification of oleic and stearic acids with linear alcohols C5-C22 and non-linear (isomeric and cyclic structure) alcohols C5-C8 was carried out in conversions above 99.5%. The alcohols did not line up in a chain length-dependent manner.
