Sulfur-containing Components Research Articles

Composition of Sulfur-Containing Components of Crude Oils from the Volga–Ural Petroleum and Gas Province: a Study by Various Mass Spectrometric Methods

Composition of Sulfur-Containing Components of Crude Oils from the Volga–Ural Petroleum and Gas Province: a Study by Various Mass Spectrometric Methods

Phosphate, magnesium containing additives and biochar regulate compost maturity and synergistically reduce odor emission in chicken manure composting: Role of physicochemical, bacterial and fungal dynamics

This study explored the odor composition and emission in chicken manure composting process, employing chemical fixatives and biochar to mitigate odors effectively. Compost maturity, ammonia, sulfur-containing odor emissions, as well as the bacterial and fungal community structure were analyzed to assess composting performance and mechanisms. The results indicated that four malodorous substances were identified as major contributors: dimethyl disulfide (Me2S2), hydrogen sulfide (H2S), methyl sulfide (Me2S), and ammonia (NH3). Biochar (BC) augmented compost maturity by enhancing the relative abundance of Thermobifida and Saccharomonospora, while reducing the emission of total malodorous sulfur-containing components by 65.3% by mitigating Halocella and Hydrogenispora, albeit without affecting NH3 emissions. Superphosphate (SP) mitigated malodorous sulfur-containing components by 51.3% through its calcium (Ca) components and associated bacteria (Pseudomonas, Halocella and Hydrogenispora). Notably, magnesium (Mg) emerged as a limiting factor for NH3 fixation by SP. The combination of SP and magnesium sulfate (MS) decreased NH3 emissions by 47.9% via the formation of struvite crystals (MgNH4PO4) and further reduced the emission of malodorous sulfur-containing components by 60.0% by enhancing functional fungi inhibiting malodorous substance production. Ultimately, the combined application of BC, SP, and MS yielded the most significant odor reduction effects, with reductions of 86.8%, 35.3%, 92.8%, and 38.8% observed in Me2S2, H2S, Me2S, and NH3, respectively.

Molecular dynamics study of waste tire pyrolysis: Focus on intermediate product evolution and sulfur migration law

With the rapid development of the automotive industry, the large number of waste tires poses significant environmental and health pressures. Pyrolysis technology offers a way to resourcefully utilize waste tires by converting them into pyrolysis oil, pyrolysis gas, and pyrolysis char, which has promising application prospects. However, there are still considerable challenges in the application of this technology, such as unclear reaction mechanisms and the high sulfur content of the products, which limit its practical implementation. Although some research has elucidated the pyrolysis mechanisms, there remain significant gaps in understanding the evolution paths of key intermediate and final products, as well as the detailed migration and transformation patterns of sulfur. This study uses reactive molecular dynamics simulation to investigate the pyrolysis process of tires. A three-dimensional polymer molecular model was constructed to study the pyrolysis process of waste tires at different temperatures, focusing on the evolution of key products, intermediate products, and sulfur-containing components. The results indicate that CH4 and ·CH3 radicals collide with unsaturated hydrocarbons through carbon-hydrogen transfer reactions and radical chain reactions, leading to polymerization. During the initial stage of pyrolysis, sulfur primarily exists in the form of sulfur-containing hydrocarbons (CHS). As pyrolysis progresses, the quantity of CHS decreases. With increasing pyrolysis temperature, the proportion of sulfur in the S form far exceeds that of CHS. At a pyrolysis temperature of 3000 K, the proportion of S is 64 %, while the proportion of CHS is 23 %.

Harnessing Nature's Potential: Innovating Antibacterial Cream through Garlic and Clove Extracts

The onset of the antibiotics period was characterised by the clinical implementation of penicillin, the inaugural antibiotic, unearthed in 1928 by Alexander Fleming in the green mould Penicillium notatum. Garlic and clove have long been used as traditional treatments for different diseases, including infections. Their antibacterial qualities have been attributed to their sulfur-containing components, such as allicin and ajoene in garlic, and eugenol and isoeugenol in clove. In this study, we wanted to produce a novel antibacterial cream leveraging the synergistic properties of garlic and clove extracts. The cream was manufactured utilizing a simple and scalable technique, and its antimicrobial activity was assessed against a panel of microbes present in our surrounding. The results indicated that the cream had considerable antibacterial action against all tested microorganisms, with minimum inhibitory concentrations (MICs) comparable to conventional antibiotics. This study establishes a groundbreaking, ecologically-oriented method for safeguarding and healing the skin. The tropical antimicrobial cream provides a secure and efficient substitute for traditional antimicrobials that may have harsh effects, while also including the nourishing and rejuvenating qualities of tropical botanicals. This groundbreaking research marks a significant advancement in the realm of natural, holistic skin health solutions. The tropical antimicrobial cream stands as a potent alternative to conventional, potentially harsh antimicrobials, offering a safe and effective way to combat skin infections and irritations. Furthermore, its incorporation of nourishing and restorative tropical botanicals transcends mere protection, promoting overall skin health and well-being. Beyond the individual benefits, this innovation holds immense potential for promoting sustainable practices within tropical ecosystems by leveraging resources responsibly and ethically. This paves the way for a future where nature's wisdom empowers us to safeguard our skin with gentle effectiveness, while simultaneously cherishing and preserving the biodiversity that holds the key to our well-being.

Effect of pre-oxidation on the rate of formation of sulfur-containing aromatic compounds during vacuum gas oil thermal cracking

It was shown that oxidation followed by heat treatment is an effective method for desulfurization of vacuum gas oil. Patterns of changes in the quantitative content of the thiophene series compounds in liquid cracking products of vacuum gas oil and liquid cracking products of pre-oxidized vacuum gas oil are described. A mixture of hydrogen peroxide and formic acid (molar ratio 3:4) was used as the oxidation system. The hypothetical mechanism for the formation of thiophene, benzo- and dibenzothiophene and their homologues from high-molecular weight components of the initial vacuum gas oil and its oxidation products is proposed. Presumably, main path of formation considerate compounds is thermal decomposition of high-molecular weight sulfur-containing components. On the basis of IR spectroscopy and structure-group analysis data, the averaged structures of such components were constructed. The influence of pre-oxidation and its conditions on the value of the rate constants for the formation of thiophene, benzo- and dibenzothiophene and their homologues during thermal cracking of initial and oxidized vacuum gas oils is studied.

S-Benzyl-L-cysteine Inhibits Growth and Photosynthesis, and Triggers Oxidative Stress in Ipomoea grandifolia

L-cysteine, a precursor of essential components for plant growth, is synthesized by the cysteine synthase complex, which includes O-acetylserine(thiol) lyase (OAS-TL) and serine acetyltransferase. In this work, we investigated how S-benzyl-L-cysteine (SBC), an OAS-TL inhibitor, affects the growth, photosynthesis, and oxidative stress of Ipomoea grandifolia plants. SBC impaired gas exchange and chlorophyll a fluorescence, indicating damage that compromised photosynthesis and reduced plant growth. Critical parameters such as the electron transport rate (J), triose phosphate utilization (TPU), light-saturation point (LSP), maximum carboxylation rate of Rubisco (Vcmax), and light-saturated net photosynthetic rate (PNmax) decreased by 19%, 20%, 22%, 23%, and 24%, respectively. The photochemical quenching coefficient (qP), quantum yield of photosystem II photochemistry (ϕPSII), electron transport rate through PSII (ETR), and stomatal conductance (gs) decreased by 12%, 19%, 19%, and 34%, respectively. Additionally, SBC decreased the maximum fluorescence yield (Fm), variable fluorescence (Fv), and chlorophyll (SPAD index) by 14%, 15%, and 15%, respectively, indicating possible damage to the photosynthetic apparatus. SBC triggered root oxidative stress by increasing malondialdehyde, reactive oxygen species, and conjugated dienes by 30%, 55%, and 61%, respectively. We hypothesize that dysfunctions in sulfur-containing components of the photosynthetic electron transport chain, such as the cytochrome b6f complex, ferredoxin, and the iron–sulfur (Fe-S) centers are the cause of these effects, which ultimately reduce the efficiency of electron transport and hinder photosynthesis in I. grandifolia plants. In short, our findings suggest that targeting OAS-TL with inhibitors like SBC could be a promising strategy for the development of novel herbicides.

Effect of exogenous selenium on physicochemical, structural, functional, thermal, and gel rheological properties of mung bean (Vigna radiate L.) protein

Selenium (Se) biofortification during the growth process of mung bean is an effective method to improve the Se content and quality. However, the effect of Se biofortification on the physicochemical properties of mung bean protein is unclear. The objective of this study was to clarify the changes in the composition, Se forms, particle structure, functional properties, thermal stability, and gel properties of mung bean protein at four Se application levels. The results showed that the Se content of mung bean protein increased in a dose-dependent manner, with 7.96-fold (P1) and 8.52-fold (P2) enhancement at the highest concentration. Exogenous Se application promotes the conversion of inorganic Se to organic Se. Among them, selenomethionine (SeMet) and methyl selenocysteine (MeSeCys) replaced Met and Cys through the S metabolic pathway and became the dominant organic Se forms in Se-enriched mung bean protein, accounting for more than 80 % of the total Se content. Exogenous Se at 30 g/hm2 significantly up-regulated protein content and promoted the synthesis of sulfur-containing protein components and hydrophobic amino acids in the presence of increased levels of SeMet and MeSeCys. Meanwhile, Cys and Met substitution altered the sulfhydryl groups (SH), β-sheets, and β-turns of protein. The particle size and microstructural characteristics depend on the protein itself and were not affected by exogenous Se. The Se-induced increase in the content of hydrophobic amino acids and β-sheets synergistically increases the thermal stability of the protein. Moderate Se application altered the functional properties of mung bean protein, which was mainly reflected in the significant increase in oil holding capacity (OHC) and foaming capacity (FC). In addition, the increase in SH and β-sheets induced by exogenous Se could alter the protein intermolecular network, contributing to the increase in storage modulus (G′) and loss modulus (G″), which resulted in the formation of more highly elastic gels. This study further promotes the application of mung bean protein in the field of food processing and provides a theoretical basis for the extensive development of Se-enriched mung bean protein.

Influences of Sulfur-Containing Components on the Key Phases of FeS Spontaneous Combustion Dynamics

ABSTRACT In petroleum storage tanks, sulfur-containing crude oil continues to corrode equipment, generating sulfur corrosion products such as FeS. These products exhibit rapid exothermic reactions upon contact with air, thereby increasing the risk of fires and explosions. Additionally, sulfur monomers precipitated from sulfur or other compounds present in crude oil can adhere to FeS, consequently altering its spontaneous combustion characteristics. To explore the impact of associated sulfur content on the spontaneous combustion characteristics of FeS during its formation, this research synthesized FeS and its sulfur mixtures with sulfur concentrations of 5%, 10%, 15%, and 20%. These mixtures were prepared using a liquid-phase method, which involved the synthesis of self-made active FeS followed by the addition of different sulfur components. Differences in the spontaneous combustion characteristics of the five groups of samples were investigated in stages by simultaneous thermal analysis. The trends of the characteristic parameters of spontaneous combustion of FeS with different percentages of sulfur-containing components were analyzed. Finally, the apparent activation energy values of FeS with FeS and its associated sulfur were calculated by using thermodynamic analysis in the room-temperature spontaneous combustion stage (RT-75℃) and high temperature combustion stage (160–250℃). The findings indicate that the presence of sulfur components enhances the reactivity of FeS, yet reduces its oxygen absorption saturation threshold, thus advancing the oxygen absorption endpoint and facilitating entry into the high-temperature combustion stage. Moreover, FeS and its associated sulfur exhibit prolonged sustained combustion times when the sulfur component percentage is below 10%, favorably influencing the combustion behavior of FeS. As the percentage of sulfur component increases (from 10% to 20%), the combustion duration temperature rises from 60°C to 95°C. Additionally, an increase in the percentage of sulfur component (from 10% to 20%) leads to a higher combustion temperature. The activation energies of the five samples were determined using the Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) kinetic methods. During the room temperature spontaneous combustion stage, the activation energy increases from 65.05 kJ/mol to 112.44 kJ/mol as the percentage of sulfur component rises from 0% to 20%. During the high temperature combustion stage, the activation energy increased from 108.32 kJ/mol to 214.49 kJ/mol with the increase in the percentage of sulfur component. FeS and its associated sulfur necessitate energy to propel the process due to heat absorption from the melting of sulfur monomers. As the reaction progresses into the high temperature stage, the required activation energy escalates accordingly.

In-situ prepared dispersed Co and Ni catalysts for heavy oil upgrading: effect of Ni, Co, and acetone on product composition

Over the past decade, much attention has been paid to oil refining using various in-situ catalysts to increase the efficiency of the process. However, the influence of the solvent in the solvent-precursor (metal salt) system on the transformation of oil components has not been studied enough. In this study, acetone was used as an environmentally friendly and cheap solvent for the preparation of catalyst precursors based on Ni and Co. The presence of acetone in the system helps to reduce the amount of introduced metal in 5 times precursors due to the uniform distribution of active components. It has been established that a mixture of Ni in acetone has the most effective catalytic activity for accelerating the process of heavy oil refining. In this experiment, the yield of light fractions increases by 2 times compared to the original oil and reaches 63 wt. %. Using by XRD and SEM were found/determine formation catalytic active Ni9S8, Ni0.96S and Co9S8 with the sulfur-containing components of heavy oil, the content of which decreases by 1.5 wt. %.

Probing the optical and molecular properties of sedimentary dissolved organic matter in the laminated diatom mats from the southern Mariana Trench

Laminated diatom mats (LDMs) deposition, formed by the aggregation of giant diatoms (e.g., Ethmodiscus rex), are recognized as a crucial driver of the global carbon and silicon cycles due to their substantial contribution to the flux of organic carbon and biogenic silica. The biogenic silica-rich sediment is one of the typical sediment types in the deep-sea setting of the tropical Pacific Ocean. Here, we analyzed the concentrations of pore-water dissolved organic carbon (DOC) and phosphate (PO43−), the optical properties, and molecular compositions of dissolved organic matter (DOM) in the two LDMs cores and one non-LDMs core retrieved from the southern Mariana Trench. Our results showed that the LDMs sediments with higher total organic carbon (TOC) contents have lower concentrations of DOC and chromophoric dissolved organic matter (CDOM), compared to the non-LDMs core. Meanwhile, the LDMs samples exhibited lower relative intensity of fluorescent proteins-like, molecular lability boundary (MLBL%) and higher values for humification index (HIX) and aromaticity modification (AImod) compared to the non-LDM core, indicating a higher level of stability and recalcitrance of DOM likely resulting from microbial degradation of relatively labile DOM compounds. Furthermore, the LDMs samples were characterized by a high abundance of CHO-containing DOM components and a low abundance of nitrogen- and sulfur-containing components, potentially linked to microbial degradation of hydrocarbon compounds that were enriched in the LDMs sediments. Additionally, the unique formulas in the LDMs samples demonstrated higher degree of recalcitrance suggested by higher aromaticity and fraction of CRAM, which may be attributed to microbial transformation of DOM. These findings add to our limited knowledge of the optical properties and molecular composition of DOM in the deep-sea opal-rich sediments, and have implications for understanding DOM cycling in the deep oceans.

Microbial Conversion of Sulfur-Containing Compounds Contributed the Natural Biodegradation of Bituminous Coals

Microorganisms can affect coal biodegradation by driving elemental biogeochemical cycling. A detailed description of the sulfur conversion process led by indigenous bacteria during coal degradation is important. This study obtained sulfur-containing compounds conversion bacteria through indoor enrichment and conducted anaerobic culture experiments using coal supplemented with enriched bacteria. The study showed that the addition of enriched bacteria changed the microbial composition, particularly the microbial groups within Pseudomonadota and Bacillota. In addition, the sulfur-containing compounds conversion bacteria increased the pore volume and specific surface area of micropores (<10 nm) and transition pores (10–100 nm), as well changed the content of sulfur-containing organic components including polypeptides, aromatic compounds, alkyl compounds, and thiazoles. The genera related to inorganic sulfur conversion were mainly belonging to Bacillota and Actinomycetota. Additionally, functional genera that can degrade sulfur-containing organic compounds of dibenzothiophenes through the ring-opening of benzene rings were found within Pseudomonadota, Bacillota and Actinomycetota. In summary, organic sulfur-related Pseudomonadota, Bacillota and Actinomycetota and inorganic sulfur-related Bacillota and Actinomycetota detected in this study could accelerate the sulfur-containing compounds conversion and ultimately increase micropores in coal, and this holds great significance for understanding the biogeochemical cycling process of coal.

Convenient high resolution mass spectrometry characterization of aromatic sulfur-containing petroleum components following by preliminary S-alkylation with aliphatic alcohols

This paper describes rather suitable and variable preliminary derivatization strategy that may precede the molecular level characterization of sulfur-containing compounds of a particularly aromatic nature by high-resolution MALDI and ESI mass spectrometry. We demonstrated for the first time that free aliphatic alcohols (primary 1-alkanols C3–C20) in the presence of triflic acid provide easy S-alkylation of not only saturated sulfides but also most typical aromatic sulfur-containing compounds (benzothiophene, dibenzothiophene and their homologues) widely distributed and frequently analyzed in oil. The reaction proceeds quantitatively at rather mild conditions and gives rise to corresponding S-alkyl sulfonium salts the cation moieties of which can be detected using MALDI and ESI mass spectrometry with excellent signal/noise (S/N) ratios; the response ratios for target ions being quite close for both methods. Collision-induced dissociation (CID) of S-alkylsulfonium cations proceeds only by the elimination of entire S-alkyl group yielding protonated molecule of the analyte. This process can be useful for a reliable determination of target aromatic heterocyclic compounds in complex mixtures. The applicability of the method is illustrated by the analysis of deasphalted medium petroleum sample. The proposed derivatization principle is considered to be highly applicable as an alternative approach to routine characterization and sensitive determination of most typical sulfur-containing compounds and particularly of aromatic S-heterocycles in crude oils by soft-ionization mass spectrometry methods.

Yb(OTf)3-Catalyzed Formal (4 + 3) Cycloaddition Reactions of 3-Benzylideneindoline-2-thiones with Donor-Acceptor Cyclopropanes.

A Yb(OTf)3-catalyzed formal (4 + 3) cycloaddition reaction of donor-acceptor cyclopropanes with 3-benzylideneindoline-2-thiones as sulfur-containing 4π components has been successfully achieved. A series of functionalized 5,10-dihydro-2H-thiepino[2,3-b]indole derivatives were synthesized with good yields and moderate to good diastereoselectivity. The reaction described herein represented the inaugural (4 + 3) cycloaddition of 3-benzylideneindoline-2-thiones.

Methane-assisted catalytic light oil desulfurization: Catalyst design, sulfur product distribution analysis and mechanistic study

The desulfurization of natural oil feedstock for fuel purposes is crucial for environmental protection and sustainable development. Methane is the main component of natural gas resources with low added value. Distinctive characteristics are demonstrated if methane can be directly used for oil desulfurization, instead of being converted into hydrogen via methane stream reforming for hydrodesulfurization. Here, the methane-assisted catalytic desulfurization process is specifically developed for light oils such as marine diesel oil. First, different catalyst supports are selected and compared, among which Al2O3 is confirmed to provide the most favorable reaction performances. Then, the reaction is operated under different gas atmospheres including CH4, N2, and H2, to reveal the uniqueness of methane for a desulfurization process. Next, model compound oils are selected with thiophene as the sulfur-containing oil component. Heptane and toluene are used as solvents to represent paraffin-rich and aromatic-rich oil, respectively. It is found that the structural characteristic of the oil significantly influences the desulfurization performance and product distribution, based on which the respective reaction mechanism networks are proposed. It is concluded that despite the unparalleled desulfurization performance under hydrogen, the methane-assisted desulfurization process demonstrates distinctive characteristics to prevent light end loss and oversaturation as well as the formation of H2S as the primary desulfurization product, which can be better utilized under certain circumstances.

Experimental study on dynamic release and transformation of sulfur during pyrolysis of Shanxi high-sulfur anthracites based on MFBRA and XPS

Pyrolytic desulfurization of two Shanxi high-sulfur anthracites was investigated experimentally under hydrogen atmospheres using a micro fluidized bed reaction analyzer (MFBRA), the dynamic release behavior of sulfur-containing gas during pyrolysis was characterized by a rapid online gas analyzer, and the transformation between sulfur-containing components in the resultant char was analyzed based on morphological and XPS characterizations. The results show that the dynamic release of sulfur-containing gas features two intensity peaks at 530–560 °C and 812–830 °C, respectively, indicating that the sulfur release proceeds by two subsequent processes: the reduction reaction of pyrite and the organic sulfur decomposition. The migration from inorganic to organic sulfur occurs predominately at lower temperatures, while the transformation between different forms of organic sulfur components is dominant at higher temperatures. Overall, the anthracite coal with a higher organic sulfur content has a higher sulfur removal efficiency in the hydrogen atmosphere. The research results provide the essential data supporting the development of highly efficient pyrolysis desulfurization technology for clean and efficient utilization of high sulfur anthracite coal resources.

Deep hydrodesulfurization of gas oils with high sulfur content: Experiment and kinetic modeling

The hydrodesulfurization of straight-run gas oils (SRGO-HS) with high content of sulfur (about 2 wt%) and its mixture with light coker gas oil (CGO) has been studied over CoMo/Al2O3 catalyst using a trickle bed down-flow reactor at the 335–365 °C, H2/HC − 300 Nm3/m3, LHSV − 0.8–2.5 h−1 and 3.5–5.1 MPa. The possibility of ultra-low sulfur diesel (<10 ppmS) production using feedstocks with sulfur content exceeding 2 wt% was demonstrated under conditions simulating industrial one. To predict the effect of process parameters on the amount of sulfur in products four kinetic models with different insight into the reactivity of individual S-containing compounds were considered. The first model is simplified kinetics based on power law rate equations, taking into account overall sulfur content, the second group includes LHHW type rate equations. The models 3 and 4 take into consideration the difference in the reactivity of sulfur-containing components. Model 3 classifies the total sulfur into two subgroups Se (easy reactive compounds) and Sr (refractory sulfur compounds - dibenzothiophene and its derivatives). In Model 4 the group Sr is divided into three more subgroups. Kinetic rate parameters i.e. frequency factors, apparent activation energies, and adsorption enthalpies, were estimated by fitting the experimental data obtained using the SRGO-HS/CGO feedstock to the models. All kinetic models predicted the experimentally determined conversions of sulfur with a relatively good accuracy (±20%). The kinetic models were verified by comparing the simulation results with the experimental data obtained using the other oil fractions (SRGO-LS) with lower content of sulfur (1.05 wt%). A better agreement was observed between the experiments and prediction by models 3 and 4.

The effect of strengthening thermal fragmentation by rotary kiln on sulfur distribution of fragmentation char with low-rank coal

Thermal fragmentation of low-rank coal was generally viewed as a negative effect. Actually, the thermal fragmentation had a positive effect on the pyrolysis desulfurization of low-rank coals, and it is expected to be a new way to realize the desulfurization of large-size char. A fixed bed pyrolysis device and rotary kiln pyrolysis device were used to investigate the effect of pure thermal action and thermo-mechanical action on the sulfur distribution in thermal fragmentation char of lignite and sub-bituminous coal at 300–900 °C. The intervention mechanism of thermo-mechanical strengthen thermal fragmentation on low-rank coal with different coalification degrees was obtained. For lignite, the non-sulfur components were more fragmented than the high-sulfur components due to thermo-mechanical action at the low-temperature stage. Fragmentation of high sulfur components dominated thermal fragmentation at the high-temperature stage. For sub-bituminous coal, conjoined structures and plastic layer hindered the fragmentation of sulfur-containing components by pure thermal action. The thermo-mechanical action under rotary kiln pyrolysis was helpful for the fragmentation of the conjoined structure and the separation of the char and plastic layer, thereby reducing the Fe-S minerals and organic sulfur content of the large-size char. The difference in organic sulfur caused by thermo-mechanical action is mainly due to the fragmentation of sulfone components.

Features of vanadium geochemistry in oils from the oil and gas fields of eastern region of Ukraine

The results of long-term studies of the geochemical features of vanadium in the oil from 36 deposits of the Eastern oil and gas region of Ukraine. Based on the results of correlation and regression analyses, the nature and forms of the relationship between the vanadium content in oil and nickel, zinc, chromium, manganese, cobalt, iron, mercury, aluminum and the total content of these metals were determined; average capacity of the productive horizon; oil density value; oil viscosity value; resin content; the density of formation water from the productive horizon; sulfur content in oil; actual depth of the productive horizon; actual temperature of the productive horizon; actual pressure of the productive horizon; oil boiling point; paraffin content; the value of mineralization for formation water from the productive horizon; content of asphaltenes. Correlation coefficients, pairwise linear regression equations as well as curves that illustrate relationships between these parameters are obtained. Based on the results of the cluster analysis, a dendrogram of the results for clustering by means of the weighted centroid method of the considered fields by the content of vanadium in the oils was elaborated. Based on the results of clustering by means of the weighted centroid method, the first natural classification of oil and gas fields of eastern region of Ukraine according to the content of vanadium in oils was developed. It has been proven that heteroatomic low-molecular sulfur-containing components of the petroleum system are the main concentrators of vanadium in the oil for the studied deposits. It has been shown that, based on the results of the cluster analysis, sample average values of vanadium concentrations that vary significantly between individual deposits or groups of deposits for established ranges could be interpreted in terms of qualitative assessment as follows: abnormally low; low; below average; average; above average; high; abnormally high. The implementation of this kind of approach makes it possible to visually compare and interpret in terms of geology various scale and various indicators of oil deposits obtained by means of experimental study. Keywords: vanadium, oil deposits, cluster analysis, linear regression equations, geochemical oil parameters, correlation coefficient.

High-valence sulfur-containing species in solid electrolyte interphase stabilizes lithium metal anodes in lithium–sulfur batteries

The interfacial stability of lithium metal anodes dictated by solid electrolyte interphase (SEI) is essential for long-cycling high-energy-density lithium–sulfur batteries. Nevertheless, critical components of SEI for interfacial stabilization are particularly indistinct. Herein, the effect of various sulfur-containing components in SEI for stabilizing lithium metal anodes is disclosed in lithium–sulfur batteries. High-valence sulfur-containing species (Li2SO3 and Li2SO4) in SEI are conducive to uniform lithium deposition and stabilizing lithium metal anodes. In contrast, low-valence sulfur-containing species (Li2S and Li2S2) in SEI result in aggressive lithium dendrites and dead lithium. This work identifies the role of sulfur-containing components in SEI for stabilizing lithium metal anodes and provides rational design principles of SEI for protecting lithium metal anodes in practical lithium–sulfur batteries.

Investigation of Filtration Phenomena of Air Pollutants on Cathode Air Filters for PEM Fuel Cells

Filtration of cathode air is one of the challenges in operating proton-exchange membrane (PEM) fuel cells. The poisoning with air contaminants can lead to rapid performance degradation and initiate an aging process of the fuel cell. Various commercially available cathode filters are being tested in a laboratory gas test bench within the research project X-EMU (03B10502B and 03B10502B2). A literature review of harmful gas contaminants in the air used for the oxygen reduction reaction (ORR) on the cathode side was conducted. Experimental investigations took place at 40 °C with synthetic humid air containing low concentration contaminants such as ammonia, nitrogen dioxide, carbon monoxide, sulfur dioxide, hydrogen sulfide, and toluene. Test durations varied from 3 to 24 h depending on the filtration efficiency. Each gas contaminant showed different reactions with the investigated filters. The filters did not let sulfur-containing components pass. However, carbon monoxide could not be filtrated by any of the tested filters. The filtration of nitrogen oxides was not efficient for all tested filters, while additional filter materials were essential for a successful filtration of ammonia. Comparative results lead to a discussion of possible effects on a fuel cell with an outlook on optimization of the filtration behavior.