Decomposition Of Oil Research Articles

Research on the effect of eco-friendly additives on selected parameters and microbial decomposition of marine diesel oil (MDO)

This paper presents the effect of environmentally friendly additives on selected parameters and microbial degradation of Marine Diesel Oil (MDO). Microbiological contamination is a serious problem in MDO and other petroleum products. For this reason, it was decided to investigate the effects of environmentally friendly additives such as silver solution and colloidal nanosilver, as well as effective liquid microorganisms and ceramic tubes with different percentages of them in diesel oil (MDO) on its selected parameters and inhibition of bacterial and fungal growth. The tests were conducted on a mixture of fuel with four types of environmentally friendly additives at concentrations of 2% and 5%, and on fuel without any additives. The effect of the additives on selected diesel parameters, including flash point, water content and acid number, as well as density and kinematic viscosity, is presented. The diesel oil was also subjected to microbiological tests. It was found that the most beneficial additive that positively influenced diesel parameters and microbial degradation was a silver solution at a concentration of 2%. The lowest ignition temperature was obtained when ionic silver was used, i.e. 60 °C, which is closest to the value for pure diesel fuel. The addition of effective microorganisms in liquid form to the fuel in an amount of 2%, increases the ignition temperature to 62.2 °C and this is the highest value obtained in comparison with other additives. The lowest water content in the test samples was obtained for the effective microorganisms in ceramic form at − 0.0068%, while the highest value was obtained for the silver solution at 0.0123%. At 100 °C, the highest kinematic viscosity was obtained for EM in ceramic, at 1.11 mm2/s. While for pure oil it was 1.03 mm2/s. For pure diesel, a value of 1.1 × 106 cfu/1 dm3 for bacteria and 7.3 × 103 cfu/1 dm3 was obtained. For each type of mixture, a value of less than 1 × 102 cfu/1 dm3 for bacteria was obtained, while in terms of fungal counts in the mixtures, a decrease of 73 times is also observed for diesel mixed with effective microorganisms in liquid form and ceramics, 48 times less was recorded after the use of non-ionic silver. The use of these additives is an innovative solution that has a positive effect on slowing down microbial degradation, without any loss of diesel performance.

Tracking hydrothermal infiltration within light oil reservoirs using organic geochemical proxies in the Shunbei area of Tarim Basin in China

Deep oil reservoirs are becoming increasingly significant fields of hydrocarbon exploration in recent decades. Hydrothermal fluid flow is deemed as a potentially crucial factor affecting the occurrence of deep oil reservoirs, such as enhancing porosity/permeability of reservoirs, accelerating oil generation and thermal cracking, and modifying organic properties of crude oils. Understanding the interplay between hydrothermal fluids and crude oils would provide useful constraints for reconstructing hydrocarbon accumulation processes and predicting the distribution patterns of crude oils. Voluminous crude oils have been discovered in the deeply buried Ordovician carbonate reservoirs within the Shunbei area of the northern Tarim Basin. Previous studies revealed that the Early Permian Tarim Large Igneous Province (LIP) has affected the Shunbei area, whereas it is still debated whether the LIP-related hydrothermal infiltration affected hydrocarbons within the Ordovician reservoirs. To resolve this puzzle, this study was designed to unravel the potential thermal impact of hydrothermal infiltration on hydrocarbons according to molecular and stable carbon isotopic compositions of oils and associated natural gases, reflectance analysis of solid bitumen, and fluid inclusion thermometry. The studied crude oils are characterized by uniform organic indicators of paraffin, terpanes, steranes, and light hydrocarbons, implying that crude oils are derived from the same source rock. Genetic binary diagrams, such as dibenzothiophene/phenanthrene (DBT/P) vs. Pr/Ph (pristane/phytane), Pr/n-C17 alkane vs. Ph/n-C18 alkane, C31R/C30hopane vs. C26/C25tricyclic terpane (TT), and C24/C23 TT vs. C22/C21 TT, indicate that marine shales deposited in a reducing-weakly oxidized environment are major source rocks. Natural gases are associated with oil reservoirs and are mainly generated via the decomposition of kerogen and crude oil. Solid bitumen with abnormally high reflectance values (2.17–2.20%) occurred in the studied area, suggesting their formation temperatures were 252–254 °C. The abnormally high temperatures may be caused by hydrothermal infiltration related to the Tarim LIP. Hydrothermal infiltration is supported by the presence of high contents of CO2 (30–48%) with enriched δ13C ratios (between − 2.5‰ and − 2.3‰), enriched n-alkane δ13C ratios, and incongruent temperatures estimated by multiple indicators, such as light hydrocarbon compositions, homogenization temperatures of fluid inclusions, and bitumen reflectance. Outcomes of this study support the interpretation that hydrothermal infiltration indeed occurred and may have facilitated hydrocarbon generation in the Shunbei area, and possibly elsewhere in the cratonic regions of the northern Tarim Basin.

Comparative analysis of wellbore electrical heating, low-frequency heating, and steam injection for in-situ conversion in continental shale oil reservoirs

In-situ conversion represents a potential method for developing immature continental shale oil, with efficient heating technology serving as its key component. This study employs coupled thermo-hydraulic-chemical numerical simulation techniques to comprehensively compare the feasibility and efficiency of three methods—wellbore electrical heating, low-frequency electrical heating, and steam injection—during the in-situ conversion process from the perspectives of reservoir heating efficiency, kerogen and heavy oil decomposition, and oil/gas production. The comparison reveals that steam injection, due to the introduction of significant water content, exhibits the poorest heating performance, whereas low-frequency electrical heating demonstrates the most effective results in reservoir heating. When employing electrical heating, particularly low-frequency methods, higher proportions of kerogen and heavy oil decomposition lead to increased overall oil and gas production. Steam heating offers advantages in heavy oil accumulation and production as well as wellbore protection, yet it yields higher water production as a drawback. Through an integrated discussion across five dimensions—heating capacity, wellbore protection, kerogen decomposition, heavy oil decomposition, and fluid production—we find that low-frequency electrical heating performs the best overall. The insights and comparisons discussed in this paper are expected to guide the selection and optimization of heating strategies for in-situ conversion.

Investigation of carbon-black emissions of a tractor biofuel diesel

BACKGROUND: On the one hand, a petroleum-based liquid fuel diesel engine is a reliable basis for tractors and self-propelled agricultural machines, and on the other hand, the current trends make us to think about the environmental component of these diesel engines and besides to remember about reasonable use of non-renewable petroleum motor fuel. In order to reduce the anthropogenic impact on natural ecosystems and to assess the smokiness of exhaust gases from a tractor diesel running on ethanol and rapeseed oil, the paper considers the relevant model of the carbon-black formation inside it. AIM: Development of the relevant model of carbon-black emission in a tractor diesel running on ethanol and rapeseed oil to assess the smokiness of exhaust gases and to reduce anthropogenic impact on natural ecosystems. METHODS: To simulate the processes of formation and burnout of carbon-black particles in a tractor diesel engine, the volume of the combustion chamber was conditionally divided into several areas (soot content indicators in different areas were added up), and the cycle of calculating the exhaust gas smokiness level included several stages (determination of pressure, integral and differential characteristics of heat dissipation, average temperature of the working fluid, fuel supply indicators and fuel evaporation rate, local coefficients of excess air, composition of gases, concentration of decomposition and oxidation products of rapeseed oil and ethanol, the number of carbon-black particles, the mass of dispersed carbon, the rate of transition of particles to the burnout zone). RESULTS: The developed mathematical model is capable of calculating the carbon-black concentration and the main components of the gas mixture in the reaction zone of the combustion chamber, the content of carbon-black in the exhaust gases at various speed and load modes of operation of a tractor diesel engine. It is capable of obtaining valuable information about the dynamics of the main stages of carbon-black formation and burnout in the cylinder of a tractor diesel engine running on ethanol and rapeseed oil. The results of numerical simulation of carbon-black formation and burnout in a tractor diesel cylinder when running on diesel fuel, ethanol and rapeseed oil are obtained and presented. CONCLUSION: Based on the developed relevant model of carbon-black emission in a tractor diesel engine running on ethanol and rapeseed oil, an assessment of its exhaust gas smokiness was carried out, clearly showing a decrease by 3.4–3.8 times in comparison with diesel fuel operation. The presented method for calculating the carbon-black emission of tractor diesel can be used in the multi-area modeling and researches of such in-cylinder processes as heat generation, heat transfer, etc. The accuracy of calculations based on the proposed model is characterized by the perfection of mathematical algorithms describing the rate of fuel evaporation, the development of a fuel flare, the determination of local temperatures, the rate of flame propagation, the local composition of gases in the cylinder, etc.

Time-varying Relationship between Oil Prices, Stock Market Performance, and Covid-19 in United States of America, China, and Malaysia: Evidence from Wavelet Approach

The purpose of this paper is to have a better understanding of the reactions to the oil price and stock market performance over a different period of the Covid-19 pandemic from January 2019 to August 2022 (Pre Covid, During Covid, and Post Covid) in the United States of America, China, and Malaysia. In the study, various approaches such as line graphs, descriptive statistics, correlation, wavelet correlation, continuous wavelet transform, and wavelet coherence analysis were used to analyse the decomposition of time series oil and stock market data in different time period. The study provides evidence of positive linear relationships between crude oil prices with the 3 countries’ stock markets in pre-covid, during-Covid and post-covid. In addition, both oil price and stock prices have evidence of a lead-lag relationship with each other, which differs in the period of time. The research results will benefit investors for better prediction during future pandemic situations and economic crises.

Study on the Inhibition Effect of C6F12O on Charged Particles in the Flame of Transformer Oil Discharge Gas

ABSTRACT The accidental combustion of insulating oil poses a significant risk in the event of transformer failure. The charged particles generated through the combustion ionization reaction exert considerable influence on the combustion speed and stability of the flame. Therefore, the detailed chemical reaction mechanism including neutral matter and charged particle is simplified. The two-dimensional finite rate reaction model is established. The theoretical calculation investigates the suppressive effect of the novel fire extinguishing agent C6F12O on charged particles in the flame resulting from transformer oil decomposition. The analysis encompasses changes in flame temperature, free radicals, and charged particles in the decomposition gas of transformer oil under C6F12O concentrations ranging from 0% to 4%. The findings reveal that the addition of C6F12O exerts a discernible inhibitory effect on the flame temperature of the transformer oil exhaust gas. The large reduction of charged particles in the flame caused by C6F12O is achieved by its consumption of large amounts of O and OH radicals in the flame. It hampers key elementary reactions responsible for charged particle generation. In conclusion, C6F12O demonstrates a pronounced inhibitory effect on charged particles in the flame resulting from transformer oil decomposition.

Effect of sesame protein/PVA nanofibers on oil separation and rheological properties in sesame paste

AbstractThis study aimed to prevent or minimize the oil phase separation that occurs during storage (0‐90 days) of sesame paste at room temperature. In order to determine the changes during storage in the sesame paste samples, the zeta potential, rheological properties, and the separated oil ratio were determined. Significant (p < 0.01) effects of applied storage time and additives on the amount of oil separated in sesame pastes were determined. The oil separated in sesame paste samples varied between 3.83% and 16.29%. While the rate of separated oil increased three times in the control group over time, it showed an insignificant (p > 0.05) increase especially in the samples where 2% nanofiber was added. It was determined that the separation of the oil phase from the structure could be prevented up to 24.73% with the addition of SPI and up to 63.02% with addition of SPINL (nanofiber containing protein isolate) compared to the control.Practical applicationsDuring storage, the particles in the sesame paste tend to precipitate, causing oil separation and residue cake, thus negatively affecting the acceptability of consumers. Additives were added in order to prevent or minimize oil phase separation, which occurs in sesame paste stored at room temperature and is not desired by consumers. As additives, nanofibers containing sesame proteins produced by the electrospinning method and sesame protein isolates (SPIs) were added. Added additives acted by preventing the separation of the oil phase from the structure. It has been determined that the addition of SPI to sesame pastes does not completely prevent the problem of oil separation in sesame paste, but is effective in delaying and reducing it. Since the oil decomposition can be reduced, the amount of oil separated and therefore the part that can sink to the bottom will decrease, so sesame paste will be consumed more appropriately and will contribute to the country's economy.

Modified Cinnabaris-stabilized Pickering emulsions loaded with the essential oil of Acorus tatarinowii Schott: preparation, characterization and in vitro evaluation.

Essential oil of Acorus tatarinowii Schott (ATEO) have significant biological activity, but their physical and chemical properties are unstable and susceptible to interference by external factors, resulting in oxidation, decomposition, and isomerization of essential oils (EOs), ultimately diminishing the quality of EOs and escalating clinical risks. In this research, based on the concept of " combination of medicine and adjuvant, " the unsuitable stabilizer Cinnabaris in Lingzhu powder prescription was modified with a SiO2 surface to become a stabilizer suitable for Pickering emulsion. The modified Cinnabaris was synthesized, with a focus on exploring the surface modification of Cinnabaris to facilitate its role as a stabilizer in Pickering emulsion. Thermal stability studies showed that modified Cinnabaris-stabilized emulsion had higher EOs retention and lower peroxide value and hydrogen peroxide content. GC-MS analysis showed that the volatile components in the emulsion were more stable than the EOs. In vitro dissolution experiments showed that in the dissolution medium of artificial gastric juice and artificial intestinal juice, compared with the ATEO, the release in Pickering emulsion was faster within 48 h, indicating that the ATEO had been encapsulated in Pickering emulsion, which could improve the in vitro dissolution rate of EOs. This study convincingly demonstrates the potential of modified Cinnabaris-stabilized Pickering emulsion to improve the thermal stability and in vitro dissolution rate of EOs.

Effects of natural and prolonged crude oil pollution on soil enzyme activities

In this study the effects of natural and long-term oil pollution levels (H: high, M: moderate and L: low) on the activity of lipase, β-glucosidase, urease, phosphatase, and dehydrogenase were analyzed. For this purpose, 120 oil-contaminated soil samples were collected from four locations located in oil-rich region of the west of Iran (Kermanshah province, Iran). After determining the physicochemical characteristics of soils, microbial counting and enzyme activities were measured. To determine the total bacterial population and bacteria involved in crude oil decomposition, bacterial counting was done in NA and CFMM culture media, respectively, which had a direct relationship with the increase in crude oil content. The average percentage of crude oil measured by Soxhlet method was 4.03%, 9.95% and 22.50% respectively for L, M and H levels. The results showed that the bacterial population increased with the increase of the contamination intensity. All the studied enzymes, except urease, had the highest activity in heavily polluted soils (H soil), and their lowest activity was observed in lightly polluted soils (L soils). Location 1 had the highest bacterial population as well as the highest activity of dehydrogenase (52.13 μg TPFg−1 h−1), acid phosphatase (35.86 μg PNPg−1 h−1), alkaline phosphatase (78.13 μg PNPg−1 h−1), lipase (92.58 μ MLA g−1 h−1) and β-glucosidase (21.67 μg PNPg−1 h−1) enzymes. In the soil samples of location 4, which had the lowest number of bacteria, the highest activity of urease enzyme (592.36 μg NH4g−1 h−1) was obtained. Principal components analysis (PCA) was also performed and 67% of the cumulative of the samples could be explained by the first two components (biochemical and physical). The findings of this research showed that natural and prolonged crude oil pollution caused the selection of oil-resistant microbial communities, and therefore we saw their positive response to the presence of oil compounds and increased enzyme activity other than urease activity.

ReaxFF Molecular Dynamics Study on the Microscopic Mechanism for Kerogen Pyrolysis.

Kerogen is mainly composed of carbon, hydrogen, and oxygen, which are the main components of crude oil and gas. The pyrolysis of kerogen is an efficient method to generate clean energy. In the present work, the pyrolysis reaction process of three types of kerogen is simulated using ReaxFF molecular dynamics (MD) methods to study the microscopic mechanism and the distribution of products. The results indicated that the pyrolysis products of the three types of kerogen significantly depend on the molecular structures, temperature, and reaction time. As the temperature increases, the gaseous hydrocarbon and the light and heavy oil fractions decreased, where small molecular fragments polymerized to form new molecular fragments. For an isothermal temperature, with the reaction proceeding, some component polymerization of the pyrolyzed fragments occurred, resulting in the generation of new light oils and heavy oils. Moreover, quantum chemical analysis was employed to reveal the kerogen pyrolysis mechanism. First, the weak bonds such as C-O, C-N, and C-S structures were decomposed to generate large carbon and some heavy shale oil fragments. Second, the cycloalkanes and long-chain alkanes were decomposed to generate a large amount of light shale oil and gaseous hydrocarbons. Finally, the decomposition of C═C in the aromatic ring, the secondary decomposition of light and heavy shale oils, and the further decomposition of short-chain alkanes occurred. In addition, the production of hydrogen (H2) occurred at the late stage of the pyrolysis reaction. Hydrogen radicals were formed by the decomposition of C-H bonds and subsequently collided with each other, resulting in the formation of H2 molecules. The pyrolysis and chemical analysis of kerogen can clearly determine the type and content of hydrocarbon substances, providing scientific data for exploration, development, and utilization of shale gas and shale oil.

Kinetics of thermal decomposition of crude oils: Insights from principal component analysis and products characterization

Energy demand is souring, and fossil fuel reserves are dwindling, making heavy oil resources more attractive. In this study, thermogravimetric and Py-GC/MS analyses were conducted on Iranian crude oil samples to compare high and low API (American Petroleum Institute) crude oils. A kinetic study based on mass loss of crude oil was performed using three model-free methods and distributed activation energy model (DAEM). To do that, TG analysis carried out, the temperature was increased from room temperature to 1000 °C with heating rates of 10, 20, and 30 °C min−1. Activation energy (Ea) and pre-exponential factor (A0) were estimated from Friedman, Kissinger–Akahira–Sunose (KAS), and Ozawa-Flynn–Wall (OFW) methods for oil sample. The Ea and A0 for heavy crude oil (Koroosh) pyrolysis varied between 59.85 and 193.83 kJ mol−1 and 1.34 × 105 to 4.36 × 1011 s−1, respectively. For light crude oil sample Lavan, the Ea and A0 ranged between 35.93 to 62.89 kJ mol−1 and 337.41–722.65 s−1, respectively. Pearson's correlation analysis found that the activation energy barrier increases as the reaction progresses and the temperature rises. This makes it harder to form the activated complex, which is a key step in the reaction. Principal component analysis supported these findings. Saturated and aromatic hydrocarbons were liberated at mild temperature while the resins and asphaltenes consecutively released in favorable condition for developing sustainable heavy oil recovery systems. Py/GC–MS analysis shows the evolution of saturated hydrocarbon in Koroosh-oil and aromatic hydrocarbons in Lavan-oil and demonstrates their suitability for fuel applications.

Study of the kinetics of aviation oils thermal conversion under non-isothermal conditions

The paper discusses the results of a kinetic study of the thermal decomposition of MS-8P, TN-98, and TN-600 aviation oils under conditions of continuous heating at a constant rate of 5 K/min to a temperature of 1 073 K. An integral method was used to describe the reaction mechanism and determine the macrokinetic parameters. It has been established that, from a phenomenological point of view, the average reaction of aviation oils conversion under the experimental conditions corresponds to the reaction model described by the surface-limited reaction equation (MS-8P), the power law (TN-98) and the model described by the three-dimensional diffusion-limited reaction equation (TN-600). When dividing the averaged reaction into two reactions (the first is completed at a temperature of 550–600 K, the second at a temperature of 638–655 K), it is determined that the first reaction is described by the reaction equation of the 2nd order (MS-8P), the first order (TN-98) and the reaction equation of one-dimensional diffusion (TN-600), and the second the reaction equation of the first order (three types of oil). The activation energy of the first reaction was 99 kJ/mol (MS-8P), 145.6 kJ/mol (TN-98) and 57.4 kJ/mol (TN-600), the value of the pre-exponential factor was – 144 241 567 min–1 (MS-8P), 62 161 395 942 min–1 (TN-98) and 236.16 min–1 (TN600). The activation energy of the second reaction is 160 kJ/mol (MS-8P), 91.6 kJ/mol (TN-98) and 127.1 kJ/mol (TN-600), the pre-exponential factor is 8.81 ‧ 1011 min–1 (MS-8P), 1.26 ‧ 104 min–1 (TN-98) and 2.04 ‧ 108 min–1 (TN-600). It is shown that the use of these values of the activation energy and the pre-exponential factor leads to agreement between the calculated values of the degree of decomposition of the studied oil samples and the experimental ones in the range of values of the degree of decomposition from 0 to 1.

Catalytic pyrolysis of straight-run light oil to light olefins: Role of molecular structure and catalytic materials

The development of straight-run light oil catalytic pyrolysis to light olefins process is an important approach of achieving the transformation and upgrading of the current oil refining industry. However, the industrialization of the catalytic pyrolysis process for straight-run light oil has been slow. Herein, we investigated the decomposition of complex straight-run light oil into different structural units and further examined their effects on light olefins production. The results indicated that the yields of light olefins cracked over MFI zeolite were about 45 % and 30 % for alkane structure and cycloalkane ring structure, respectively. Further analysis showed that the olefin structure could theoretically be cracked to 100 % light olefins, but in fact, 40 % of the light olefins were lost due to the transfer of 10 % hydrogen. Subsequently, the effects of zeolite topology and acid properties on the cracking of different structural units were further analyzed. It was found that zeolites with MTT and MFI topologies contributed to the catalytic pyrolysis of chain and cycloalkane ring structures, respectively, because appropriate pore size helped diffusion of hydrocarbon molecules and inhibited side reactions such as hydrogen transfer. Compared with MFI zeolite, the light olefins yield produced by chain structure cracking over MTT zeolite increased by 5.83 %-10.54 %. In addition, it was discovered that zeolites with total and strong acids in the range of 0.2–0.4 mmol/g and 0.1–0.2 mmol/g, respectively, were beneficial for the cracking of light alkanes in straight-run light oils to light olefins. This work provides useful insights into the fundamental understanding and development of straight-run light oil catalytic pyrolysis to light olefins process.

The Prokaryotic Community Structure of Oil-Contaminated Chernozem during the Introduction of Nitrate and Potassium Chloride

The effect of nitrate and potassium chloride salts, on the structure of the metabolically active prokaryotic community of oil-contaminated chernozem has been studied. Molecular biological approaches and bioinformatic methods of analysis were used in the study. The objects of the study were samples of chernozem selected in the Voronezh region (N 51°1′41″, E 40°43′31″). The phylogenetic and functional diversity of the prokaryotic complex of oil-contaminated chernozem was considered when introducing nitrate and potassium chloride under conditions of a slightly alkaline reaction of the medium. Contamination of chernozem with oil in an amount of 5% of the soil mass led to alkalinization of the medium from 7.1 to 7.9. The introduction of nitrate and potassium chloride, both separately and together in a total dose of 2 mmol/100 g of soil removed this negative effect. The combined addition of nitrate and potassium chloride led to a more than twofold increase in the biomass of metabolically active prokaryotic cells and the number of copies of functional genes responsible for the synthesis of alkanmonooxygenase enzymes involved in the decomposition of oil. In the presence of oil, the formation of a specific complex of bacteria was revealed, in which representatives of A-ctinobacteria (Rhodococcus erythropolis) and Alphaproteobacteria (Bradyrhizobium japonicum) prevailed. Rhodococcus erythropolis and Bradyrhizobium japonicum, being autochthonous organisms in uncontaminated soil, began to occupy dominant positions in oil-contaminated samples, and the introduction of nitrates enhanced this effect.

Adsorption of SF6 gas and insulating oil decomposition gas by CoO-doped SnSe monolayer in various environments: A study of strong adsorption performance

Taking into account that Sulfur hexafluoride (SF6) gas leakage can result in environmental pollution, the insulating oil used in high-voltage equipment can decompose into various detectable dissolved gases, allowing for the monitoring of its operational status. In this study, we use a CoO-doped SnSe (SnSe-CoO) monolayer to achieve strong adsorption of SF6 gas, CO, and C2H2 gas, and highly sensitive monitoring of H2 and CH4. Thus, the SnSe-CoO monolayer can serve as an adsorbent for SF6 gas leakage and a material for monitoring insulating oil-dissolved gas. Furthermore, we also observed that the adsorption energy of each gas on the intrinsic material increases with the solvent dielectric constant, facilitating the control of gas adsorption. Our research provides a significant theoretical foundation for future adsorption and monitoring of insulating gases and insulating oil decomposition gases.

Enzymatic Assessment of the State of Oil-Contaminated Soils in the South of Russia after Bioremediation.

Soil pollution with oil as a result of accidents at oil pipelines and oil refineries is a frequent occurrence in the south of Russia. To restore such polluted lands, it is necessary to carry out soil remediation measures. This work aimed to evaluate the use of ameliorants of various natures (biochar, sodium humate, and microbial preparation Baikal EM-1) to restore the ecological state of oil-contaminated soils with different properties (Haplic Chernozem, Haplic Arenosols, Haplic Cambisols). To assess the ecological state of soils, the following physicochemical and biological indicators were studied: residual oil content, redox potential, and medium reaction (pH). Changes in enzymatic activity were also studied, including catalase, dehydrogenases, invertase, urease, and phosphatase. The greatest decomposition of oil in Haplic Chernozem and Haplic Cambisols was provided by Baikal EM-1 (56 and 26%), and in Haplic Arenosols, this was provided by biochar (94%) and sodium humate (93%). In oil-contaminated Haplic Cambisols, the content of easily soluble salts with the addition of biochar and Baikal EM-1 increased by 83 and 58%, respectively. The introduction of biochar caused an increase in pH from 5.3 (Haplic Cambisols) to 8.2 (Haplic Arenosols). The introduction of oil-contaminated Haplic Arenosols of biochar, humate, and Baikal stimulated the activity of catalase and dehydrogenases by 52-245%. The activity of invertase was stimulated in the Haplic Chernozem after the introduction of ameliorants by 15-50%. The activity of urease was stimulated after the introduction of ameliorants into borax and Arenosol by 15-250%. The most effective ameliorant for restoring the ecological state of Haplic Cambisols after oil pollution was biochar. For Haplic Arenosols, this was sodium humate, and for Haplic Chernozem, the effectiveness of biochar and sodium humate did not differ. The most informative indicator for the remediation of Haplic Chernozem and Haplic Cambisols was the activity of dehydrogenases, and for Haplic Arenosols, this was the activity of phosphatase. The results of the study should be used to biomonitor the ecological state of oil-contaminated soils after bioremediation.

Incorporation of wet gases to kerogen in petroleum formation and evolution

The formation mechanism for thermogenic gas remains unresolved. Disputes are focused on: (1) stability barrier for decomposition of oil to gas and wet gas to methane, and (2) inconsistence in dryness ratio (C1/ΣC1–5) between gases produced in pyrolysis experiments and in natural reservoirs. Here, we demonstrate the variation trend of dryness ratio (C1/ΣC1–5) with temperatures and thermal stress levels, and the correlation of dryness ratios with the yields of liquid components (ΣC8+) in confined pyrolysis experiments (gold capsules) of twenty coals. At both heating rates of 2 and 20 °C/h, dryness ratios of gaseous hydrocarbons at first decrease, and then increase with increasing temperatures and thermal stress levels. Dryness ratios of produced gases can be very high in the range of 66.3–95.7 wt% at initial temperature about 334 °C and heating rate of 20 °C/h, corresponding to EASY%Ro 0.56. We suggest that these gases are not the original products released from kerogen, but have been altered via wet gas incorporation to kerogen. Larger oil molecules (C8+) are more competitive in incorporating to kerogen compared with wet gases, and therefore, prohibit wet gas incorporation, leading to the observed trend of gas dryness ratios with increasing temperature and maturity and the negative correlation between dryness ratios and the yields of liquid components (ΣC8+). The conflicting results between the yields and carbon isotopes of wet gases produced in the isothermal confined pyrolysis experiments for coal plus oil can be well interpreted using the reaction mechanism that wet gases incorporate to kerogen while oil components retard this incorporation. Once free oil and wet gas molecules are reincorporated to kerogen, the bound molecules can easily decompose to smaller molecules due to substantial reduction of activation energy for carbon-carbon bond rupture. Petroleum formation from kerogen can be a recycling process: kerogen first releases oil compounds, and then free molecules reincorporate to kerogen and further decompose to smaller molecules, and finally to methane.

Manganese Oxide Loaded Carbon Fiber for Solar Energy Harvesting and Oil Decomposition

In this work, a manganese oxide electrode, containing carbon nanofiber composites (MnO2/CNF), has been made through electrospinning, oxidization, and partial carbonization high-temperature treatment. Scanning electron microscopy (SEM) was used to observe the morphology of the nanofiber and analyze the composition of the fiber. The fiber size range and element distribution were determined. The oxide nanoparticles were modeled as electrorheological suspensions in the polyacrylonitrile polymer solution during electrospinning. The dielectrophoretic behavior of the particles subjected to non-uniform electric fields were analyzed and the motion of the oxide particles under the actions from fluctuating electric fields was investigated to explain the sporadic distribution of nanoparticles within the composite nanofibers. A photoactive anode was made from the composite nanofiber and the decomposition of spilled oil was performed under sunlight illumination. It was observed that the manganese oxide containing carbon nanofiber composite electrode can generate electricity and clean the spilled oil under sunlight. Both energy conversion and environment cleaning concepts were demonstrated.

STUDY OF OIL DEGRADATION IN OIL-CONTAMINATED SOIL DURING PURIFICATION USING A BIOLOGICAL PRODUCT

During a scientific study, a laboratory experiment was conducted to investigate the degradation of oil by various microorganisms in a liquid mineral medium containing 2% oil. This experiment was conducted at temperatures of 24ºC and 5ºC for a duration of 10 days. Using infrared spectroscopy (IR spectroscopy), the degree of oil decomposition by each microorganism was determined. Based on these data, four associations of microorganisms were created, which proved to be effective in breaking down oil hydrocarbons. Using gravimetry and IR spectrometry, the degree of oil biodegradation by these microorganism associations was assessed, ranging from 30% to 70%. Based on the data obtained regarding microbial associations, a new bio-preparation was developed, containing the Pseudomonas sp. K3-H strain and two Rhodococcus strains (F2/2-Н4, F2/1-Н4). Subsequently, fieldwork was conducted on the premises of oil waste of the company "TOO Company – Daulet Asia." Over a period of 12 weeks, the population of oil-degrading microorganisms at the oil-contaminated site reached the required level, resulting in an 89.67% reduction in the amount of oil. It is worth noting that the ambient temperature varied from 05 to 39°C during the day and from 0 to 24°C at night during this period. The results of the field studies demonstrated the effectiveness of the developed bio-preparation based on the Rhodococcus erythropolis KZ1, Rhodococcus erythropolis KZ2, and Pseudomonas putida KZ3 strains. Thus, the proposed bioremediation strategy utilizing the developed bio-preparation successfully passed the testing phase at the landfill of "TOO Company - Daulet Asia" in the Kyzylorda region of the Republic of Kazakhstan.

Features of the self-restoration of the oil-contaminated peat-bog soil – a field study

The features of self-restoration processes of the oligotrophic peat-bog soil disturbed by crude oil pollution were studied. Soil contamination was carried out in field long-term experience. The key soil self-recovery indicators were: (1) the rate of carbon dioxide emission by the soil, which quantitatively characterizes the mineralization of petroleum hydrocarbons by microorganisms; (2) content of petroleum products. The microorganisms of the studied soil were characterized by low resistance to the toxic effects of oil: during the first three years of the experiment, the respiration of oil-contaminated soils was significantly lower than in pure soil. Restoration of microbial respiration to the control level and its further intensive growth occurred after 4-5 years of the experiment only in soils with low oil doses: 0.3 and 0.6 l m-2. In time, this coincided with the maximum rate of oil decomposition, which indicates the microbial nature of its utilization. The respiration of soil with oil high doses (1.8 and 3.0 l m-2) remained significantly lower than in pure soil throughout the entire experiment. At the same time, the amount of oil products in these samples markedly decreased. Oil degradation in these variants could occur due to the activity of anaerobic bacteria or abiotic processes.