Oil Fractions Research Articles

Long-term management of rice agroecosystem towards climate change mitigation

The Intergovernmental Panel on Climate Change recognize to agriculture the responsibility for about 15 % of global anthropogenic greenhouse gas (GHG) emissions, contributing to global warming. The increasing nutrient inputs in industrial agriculture affect the GHG concentration in the atmosphere and varies substantially due to rate and type of fertilizers applied to the crops, making the management more or less sustainable. In this perspective, this study has investigated at small scale the effect of different adjusted agricultural management practices, based on different nutrient dosage, to optimize the effect of rice cropping systems on carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions. Farmyard manure (FYM), rice stubbles and Azolla integrated with chemical fertilizers have been correlated with microbial and enzymatic activities, and with different carbon and nitrogen fractions in acid Inceptisol. Results have revealed that the integrated nutrient management used in rice-rice agroecosystem yielded a peak for CO2 and CH4 emissions, whereas two peaks for N2O emission. This study has shown an increase in greenhouse gas emission intensity (GHGI) and grain yield of rice in the following order: rice stubbles > FYM > Azolla and it has confirmed CH4 emission as the dominant contributor to GHGI from the rice-rice agroecosystem. When analyzed together GHGs emission and soil properties, a positive correlation was found with biological properties as well as with the different carbon and nitrogen fractions in soil. The highest GHGI has been highlighted in the treatment where recommended dose of chemical fertilizers has been combined with rice stubbles, primarily due to the increase in CH4 emissions. In contrast, the lowest GHGI has been exhibited in Azolla treated plot, probably due to the cumulative effects of the photosynthetic rate of Azolla, the release of oxygen from the Azolla roots, and the physical protection capacity of the Azolla cover, which partially avoid the CH4 diffusion from the standing water. The seasonality did not affect the estimated rates of GHGI that have been lower both in case of winter and autumn rice compared to previous studies, probably for dissimilarities in management practices. Further research is required in other cropping sequences for addressing the ecological contribution of smallholder agriculture to help reducing GHG emissions, thus, mitigating global warming with actions at local scale.

Effect of severe wildfire on soil phosphorus fractions and adsorption in a cold temperate coniferous forest after 5 years

AbstractForest fires are a primary driver of biogeochemical processes in ecosystems and affect the soil nutrient balance by altering the distribution of organic matter and associated nutrients as well as the composition and availability of elemental nutrients. We investigated the changes in soils’ phosphorus (P) fractions and the adsorption characteristics of potassium dihydrogen orthophosphate (orthoP) and myo‐inositol hexakisphosphate (IHP) at two depths (0–5 and 5–10 cm) in soils from two sites differing in fire severity: long‐unburned and heavily burned. Five years after the fire, there were increases in the total P and extractable inorganic P (H2O‐P, NaHCO3‐Pi, NaOH‐Pi, D.HCl‐Pi and C.HCl‐Pi) contents. Conversely, there was a decrease in organic P (NaHCO3‐Po, NaOH‐Po and C.HCl‐Po). The adsorption of soil for orthoP at a depth of 0–5 cm was dependent on the amount of P supplied by the soil; at low concentrations, heavily burned soil showed a lower adsorption than long‐unburned soil. However, at high concentrations, the adsorption of heavily burned soil was significantly larger than that of long‐unburned soil. With respect to IHP, the adsorption of long‐unburned soil was also more significant at depths of 0–5 cm. The adsorption of both orthoP and IHP of heavily burned soil was significantly higher than that of long‐unburned soil at a depth of 5–10 cm. Fire also decreased the binding degree (k1) of soil‐P and the solid phase at depths of 0–5 and 5–10 cm. The increase in P adsorption capacity outweighed the addition of P from ash, resulting in less leaching in heavily burned areas and minimizing P loss. Overall, forest fires significantly affect the adsorption characteristics and P fractions of soil, specifically orthoP and IHP, during the initial stage of postfire recovery. These effects are closely related to the direct influences of iron oxide, soil organic matter and aluminium oxide in the soil and may even produce relatively long‐term effects on the P recycling process of the entire ecosystem.

Исследование нефтеемкости природных опоков Астраханской области

The article deals with the issues of studying the absorption capacity of oil and petroleum products (oil capacity) by a natural sorbent- the flask of the Central Kamennoyarsk field of the Astrakhan region. The study of oil capacity makes it possible to determine the possibility of using natural flakes as oil sorbents to collect oil and more viscous petroleum products from the surface of soils and hard coatings. In this work, the influence of the granulometric composition of the sorbent, the sorption temperature and the viscosity characteristics of oil and petroleum products on the oil capacity of the sorbent is studied. The regularities of the absorption capacity of natural flakes in the presence of oil, fuel oil, oil, gasoline and diesel fractions at temperature range from –5 to 40°C have been established. To determine the oil capacity, a static research method was used, in which the sorbent was not subjected to mechanical mixing during contact with the petroleum product. Thus, when testing sorbent fractions with particle sizes less than 1 and 2.5 mm it was stated that high oil capacity results (0.79-0.88 g/g) were achieved at temperature range from –5 and 20ºC in the presence of fuel oil and oil. The greatest sorption effect is achieved due to the influence of external adsorption and the adhesive action of high-viscosity petroleum products. A further increase in temperature to 40ºC reduces the viscosity of petroleum products and prevents the formation of a stable mixture with the sorbent. Relatively low values of the sorption capacity were obtained in the presence of watered oil. Regardless of the temperature, the oil capacity does not exceed 0.75 g/g. The collection of gasoline and diesel fuel is ineffective due to their low viscosity and high volatility.

Permafrost degradation and its consequences for carbon storage in soils of Interior Alaska

Permafrost soils in the northern hemisphere are known to harbor large amounts of soil organic matter (SOM). Global climate warming endangers this stable soil organic carbon (SOC) pool by triggering permafrost thaw and deepening the active layer, while at the same time progressing soil formation. But depending, e.g., on ice content or drainage, conditions in the degraded permafrost can range from water-saturated/anoxic to dry/oxic, with concomitant shifts in SOM stabilizing mechanisms. In this field study in Interior Alaska, we investigated two sites featuring degraded permafrost, one water-saturated and the other well-drained, alongside a third site with intact permafrost. Soil aggregate- and density fractions highlighted that permafrost thaw promoted macroaggregate formation, amplified by the incorporation of particulate organic matter, in topsoils of both degradation sites, thus potentially counteracting a decrease in topsoil SOC induced by the permafrost thawing. However, the subsoils were found to store notably less SOC than the intact permafrost in all fractions of both degradation sites. Our investigations revealed up to net 75% smaller SOC storage in the upper 100 cm of degraded permafrost soils as compared to the intact one, predominantly related to the subsoils, while differences between soils of wet and dry degraded landscapes were minor. This study provides evidence that the consideration of different permafrost degradation landscapes and the employment of soil fractionation techniques is a useful combination to investigate soil development and SOM stabilization processes in this sensitive ecosystem.

Biological Activities and Chemical Compositions of Prangos platychlaena Boiss. Essential Oil and Fractions, Multivariate Statistical Analyses.

In this research, essential oil was obtained from the aerial parts of Prangos platychlaena Boiss. by hydrodistillation using a Clevenger-type apparatus, separated into fractions having different polarities by column chromatography. Both essential oil and the fractions were analyzed by GC-FID and GC/MS simultaneously. Nona-3,5-diyne-2-yl acetate (46%) and 3,5-nonadiyne (13.5%) were found to be the main constituents of the essential oil. While the main components of the n-hexane fraction were characterized as 3,5-nonadiyne (45.6%) and germacrene B (16.4%), the major components of the methanol fraction were found to be nona-3,5-diyne-2-yl acetate (59.6%) and 3,5-nonadiyne-2-ol (25.9%). In addition, principal multivariate statistical analyses were performed with principal component analyses and Venn diagram calculations, utilizing chemical compositions of the essential oil and the fractions. Furthermore, in vitro anti-inflammatory activities of the essential oil and the fractions were evaluated to correlate the chemical composition with the biological activity, and to the best of our knowledge, this study was performed for the first time in this aspect. LOX inhibitions of the essential oil, n-hexane, and methanol fractions were determined to be 70.98 ± 1.7, 67.10 ± 2.5, and 50.11 ± 4.8%, respectively. Preliminary initial findings of this study will be extended in the future with new biological assays.

Development of the composition of anoxidation-stable dressing with high nutritional value

The solution to the problem of developing an oxidation-stable dressing with high nutritional value based on unrefined first cold-pressed linseed, corn and sesame oils is considered. The objects of the study are the following indicators: antioxidant, fatty acid composition, induction period of accelerated oxidation of oils, blends and finished products. The rational range of oilratios in the blend, enriched with a-linolenic acid, stabilized against oxidative spoilage due to natural antioxidants – tocopherols, sesamol, sesamolin, is substantiated. The ratio of linseed, corn and sesame oils is 1:2:1, respectively. The characteristics of the blend are as follows: the ratio of ω-3:ω-6 fatty acids is 1:1.7; the induction period of accelerated oxidation (at 80 °C) – 4.1 h. A model sample of the dressing was produced using the developed blend. It was proven that the sample of the dressing of the proposed composition retains its organoleptic and physico-chemical parameters (titratable acidity, dry matter content, acid and peroxide values of the oil fraction) during 30 days of storage at a temperature of 8±1 °C. A feature of the obtained results is the possibility of increasing the nutritional value of the dressing based on unrefined oils while preserving the extended shelf life of products. From a practical point of view, the development of such products allows expanding the range of competitive dressings with high nutritional value. An applied aspect of using the obtained scientific result is the possibility of modeling the composition of dressings or other oil products based on valuable oil raw materials, depending on the ratios of the oil base components of the product

Diversity and Biotechnological Potential of Cultivable Halophilic and Halotolerant Bacteria from the "Los Negritos" Geothermal Area.

Soil salinization is negatively affecting soils globally, and the spread of this problem is of great concern due to the loss of functions and benefits offered by the soil resource. In the present study, we explored the diversity of halophilic and halotolerant microorganisms in the arable fraction of a sodic-saline soil without agricultural practices and two soils with agricultural practices (one sodic and one saline) near the geothermal area "Los Negritos" in Villamar, Michoacán state. This was achieved through their isolation and molecular identification, as well as the characterization of their potential for the production of metabolites and enzymes of biotechnological interest under saline conditions. Using culture-dependent techniques, 62 halotolerant and moderately halophilic strains belonging to the genera Bacillus, Brachybacterium, Gracilibacillus, Halobacillus, Halomonas, Kocuria, Marinococcus, Nesterenkonia, Oceanobacillus, Planococcus, Priestia, Salibactetium, Salimicrobium, Salinicoccus, Staphylococcus, Terribacillus, and Virgibacillus were isolated. The different strains synthesized hydrolytic enzymes under 15% (w/v) of salts, as well as metabolites with plant-growth-promoting (PGP) characteristics, such as indole acetic acid (IAA), under saline conditions. Furthermore, the production of biopolymers was detected among the strains; members of Bacillus, Halomonas, Staphylococcus, and Salinicoccus showed extracellular polymeric substance (EPS) production, and the strain Halomonas sp. LNSP3E3-1.2 produced polyhydroxybutyrate (PHB) under 10% (w/v) of total salts.

Revealing the synergistic effect of hydration and pulsed ultrasound on the emulsifying properties of silkworm pupa protein and its stabilized emulsion.

Silkworm (Bombyx moil L.) Pupa protein (SPP) is a high-quality insect protein and is considered a sustainable alternative source for traditional animal food protein. However, the utilization of SPP is limited because of its low solubility and emulsifying ability. In the present study, the synergistic effect of hydration and pulsed ultrasound on the physicochemical properties of SPP and SPP-stabilized Pickering emulsions was evaluated. Pulsed ultrasound changed the particle size of SPP and its conformation. As the pulsed ultrasound increased from 0 s to 5 s, the α-helix and SS contents of SPP decreased, whereas the β-sheet and SH contents increased, which in turn improved its solubility and amphiphilicity. As a result, the SPP treated by a combination of 12 h of hydration and 3 s of ultrasound exhibited a contact angle of 74.95°, hydrophobicity of 904.83, EAI of 6.66 m2 g-1 and ESI of 190.69 min. Compared with the combination of 1 h of hydration and 5 s of ultrasound, the combination of 12 h of hydration and 3 s of ultrasound exerted more soluble and hydrophobic SPP, whereas the EAI and ESI of the samples were higher. Notably, the ultrasound-treated SPP can form a stable gel-like emulsion (oil fraction ranging from 70% to 80%). The combination of hydration and ultrasound can effectively improve the physicochemical characteristics of SPP as well as its emulsion stability. Sufficient hydration is a cost-effective method for facilitating the modification of proteins by ultrasound treatment. © 2024 Society of Chemical Industry.

Efficient Capture of Cannabis Terpenes in Olive Oil during Microwave-Assisted Cannabinoid Decarboxylation.

The development of selective extraction protocols for Cannabis-inflorescence constituents is still a significant challenge. The characteristic Cannabis fragrance can be mainly ascribed to monoterpenes, sesquiterpenes and oxygenated terpenoids. This work investigates the entrapment of Cannabis terpenes in olive oil from inflorescences via stripping under mild vacuum during the rapid microwave-assisted decarboxylation of cannabinoids (MW, 120 °C, 30 min) and after subsequent extraction of cannabinoids (60 and 100 °C). The profiles of the volatiles collected in the oil samples before and after the extraction step were evaluated using static headspace solid-phase microextraction (HS-SPME), followed by gas chromatography coupled to mass spectrometry (GC-MS). Between the three fractions obtained, the first shows the highest volatile content (~37,400 mg/kg oil), with α-pinene, β-pinene, β-myrcene, limonene and trans-β-caryophyllene as the main components. The MW-assisted extraction at 60 and 100 °C of inflorescences using the collected oil fractions allowed an increase of 70% and 86% of total terpene content, respectively. Considering the initial terpene amount of 91,324.7 ± 2774.4 mg/kg dry inflorescences, the percentage of recovery after decarboxylation was close to 58% (mainly monoterpenes), while it reached nearly 100% (including sesquiterpenes) after extraction. The selective and efficient extraction of volatile compounds, while avoiding direct contact between the matrix and extraction solvents, paves the way for specific applications in various aromatic plants. In this context, aromatized extracts can be employed to create innovative Cannabis-based products within the hemp processing industry, as well as in perfumery, cosmetics, dietary supplements, food, and the pharmaceutical industry.

Duration of Steam Distillation Affects Essential Oil Fractions in Immortelle (Helichrysum italicum)

The composition of the essential oil depends on the duration and conditions under which the distillation of the plant material is carried out. In this study, one sample without fractionation and eight fractions (each after 15 min of steam distillation) of the essential oil of cultivated H. italicum were analysed by gas chromatography-mass spectrometry (GC-MS). The steam conditions for all samples were as follows: flow rate 800 L/h, temperature 104 °C, and pressure 0.4 bar. The test of the antimicrobial activity was performed with the modified Kirby–Bauer method (disc diffusion method) on non-selective nutrient media (blood agar) using the reference bacterial and fungal strains. A total of 75 different components were found in the essential oil samples obtained. A shorter distillation time makes the oil richer in monoterpenes and more suitable for the perfume and cosmetics industry. On the other hand, prolonged distillation leads to the essential oil being enriched with sesquiterpene oxides, which can have a negative effect on the fragrance of the essential oil. The essential oil of H. italicum showed antimicrobial activity only against Staphylococcus aureus ATCC 25923, and the best activity was shown by the sixth fraction.

Multicomponent Photocatalytic-Dispersant System for Oil Spill Remediation.

In the present work, the potential application of a fabricated halloysite nanotubes-Ag-TiO2 (HNT-Ag-TiO2) composite loaded with a binary surfactant mixture made up of lecithin and Tween 80 (LT80) in remediating oil spillages was examined. The as-prepared Ag-TiO2 that was used in the fabrication of the HNT-Ag-TiO2-LT80 composite was characterized by X-ray diffraction, Raman spectroscopy, UV-vis and diffuse reflectance spectroscopy, CV analyses, and SEM-EDX. The synthesized composite was also characterized by thermogravimetric analysis, Fourier-transform infrared spectroscopy, and scanning electron microscopy-energy dispersive X-ray spectroscopy. The synthesized composite was active in both the UV and visible light regions of the electromagnetic spectrum. The oil-remediating potential of the as-prepared composite was examined on crude oil, and aromatics and asphaltene fractions of crude oil. The composite was able to reduce the surface tension, form stable emulsions and smaller oil droplet sizes, and achieve a high dispersion effectiveness of 91.5%. A mixture of each of the crude oil and its fractions and HNT-Ag-TiO2-LT80 was subjected to photodegradation under UV light irradiation. The results from the GC-MS and UV-vis analysis of the photodegraded crude oil revealed that the photocatal composite was able to photodegrade the crude oil, aromatics, and asphaltene fractions of crude oil with the formation of intermediate photodegradation products depicting that the HNT-Ag-TiO2-LT80 has a potential as an oil spill remediation material.

Agroforestry systems affect soil organic carbon stocks and fractions in deforested landscapes of Amazonia

Agroforestry systems affect soil organic carbon stocks and fractions in deforested landscapes of Amazonia

ИЗУЧЕНИЕ МЕТОДОМ ГАЗОЖИДКОСТНОЙ ХРОМАТОГРАФИИ СУММАРНОГО СОДЕРЖАНИЯ АЛКАНОВ, АРЕНОВ И ИЗОПРЕНОИДНЫХ АЛКАНОВ В НЕФТЕПРОДУКТАХ ДО И ПОСЛЕ ИХ ВЫГОРАНИЯ НА ПОЖАРАХ

The compositions of petroleum products obtained from different oil fractions were studied by gas-liquid chromatography. It is shown, that in order to establish the nature of the oil product before and after exposure to high temperatures in the fire-technical examination,
 it is necessary, along with the identification of peaks on chromatograms by chromatographic parameters, to process them using the internal normalization method. To establish the nature of the oil product and the fraction of oil from which this oil product was obtained, it was proposed to group all identified hydrocarbons into three main groups (alkanes, arenes, isoprenoids).
 To determine from which fraction of oil the oil product was obtained, it is sufficient to estimate the relative content of the selected groups.
 For petroleum products of the gasoline fraction, the group of arenes is the predominant group, and for petroleum products of the medium distillate fractions of oil, the group of alkanes predominates in their compositions. To determine the type of petroleum product both before and after exposure to high temperatures in the fire zone, it is sufficient to determine the alkane whose content in the alkane group is maximum, as well as to analyze the content of arene subgroups and identify the arene subgroup whose contribution to the composition of the oil product is maximum. In addition, to confirm that an oil product belongs to gasoline or diesel fuels, it is sufficient to detect in its composition a group of tetramethylbenzenes or alkanes of an isoprenoid structure, respectively.

Carbon persistence of soils with long‐term biosolids amendments in California agroecosystems

AbstractBiosolids can build soil organic matter, but their ability to increase carbon and nitrogen in persistent fractions in deep soil is not well understood. We aimed to assess the mechanisms that influence soil carbon and nitrogen dynamics at three sites—Sacramento (irrigated, grazed grassland), Solano (rainfed, grazed grassland), and Merced (feed cropping system with alfalfa–corn rotation)—where soils were amended with biosolids for 20 years using density fractionations, organomineral extractions, and correlations between calcium and soil organic carbon at three depths (0–10, 30–50, and 75–100 cm). We found that amended soils had higher carbon and nitrogen content in the free‐ and occluded‐light fractions at all depths relative to the control in the Sacramento and Solano sites; however, the Merced site had a greater relative increase of carbon and nitrogen associated with the heavy fraction. Effect sizes show that biosolids increase carbon and nitrogen content in free‐ and occluded‐light fractions in the surface soil (0–10 cm), and in both light and heavy fractions in the deep soil layer (75–100 cm). Ratios of carbon to iron and aluminum show that chelation is an important mechanism of carbon stabilization in Sacramento and Solano sites throughout the soil profile. No (0–10 cm) to negative (75–100 cm) correlations were observed between calcium and soil carbon in the amended soils in the Merced site. Our results indicate that, while biosolids are typically incorporated at shallow depths, long‐term application of biosolids can increase the amount of free‐ and occluded‐light carbon fractions in deep soil.

Transcriptome analysis of Sparidentex hasta larvae exposed to water-accommodated fraction of Kuwait crude oil

Anthropogenic activities have been shown to significantly affect marine life. Water pollution and oil spills are particularly deleterious to the fish population, especially during their larval stage. In this study, Sobaity-sea bream Sparidentex hasta (Valenciennes, 1830) larvae were exposed to serial dilutions of water-accommodated fraction of Kuwait crude oil (KCO-WAF) for varying durations (3, 6, 24, 48, 72 or 96 h) in acute exposure regime. Gene expression was assessed using RNA sequencing and validated through RT-qPCR. The RNA sequencing data were aligned to the sequenced genome, and differentially expressed genes were identified in response to treatment with or without KCO-WAF at various exposure times. The highest number of differentially expressed genes was observed at the early time point of 6 h of post-exposure to KCO-WAF. The lowest number of differentially expressed genes were noticed at 96 h of treatment indicating early response of the larvae to KCO-WAF contaminant. The acquired information on the differentially expressed genes was then used for functional and pathway analysis. More than 90% of the differentially expressed genes had a significant BLAST match, with the two most common matching species being Acanthopagrus latus and Sparus aurata. Approximately 65% of the differentially expressed genes had Gene Ontology annotations, whereas > 35% of the genes had KEGG pathway annotations. The differentially expressed genes were found to be enriched for various signaling pathways (e.g., MAPK, cAMP, PI3K-Akt) and nervous system-related pathways (e.g., neurodegeneration, axon guidance, glutamatergic synapse, GABAergic synapse). Early exposure modulated the signaling pathways, while KCO-WAF exposure of larvae for a longer duration affected the neurodegenerative/nervous system-related pathways. RT-qPCR analysis confirmed the differential expression of genes at each time point. These findings provide insights into the underlying molecular mechanisms of the deleterious effects of acute exposure to oil pollution—on marine fish populations, particularly at the early larval stage of Sparidentex hasta.

Soil quality dynamics and degradation potentials as influenced by land use systems in humid tropical soil of Southeastern, Nigeria

An assessment of the effects of land use systems on soil quality dynamics and soil degradation potentials in Umuahia, Southeastern Nigeria was done in this study. Samples of soil were taken between 0 and 15 and between 15 and 30 cm. from coconut plantation (SSP1), palm plantation (SSP2), pineapple orchard (SSP3) and waste dump site (SSP4). The result revealed sand to be the dominant soil fraction in decreasing abundance: Waste dumpsite (WD)≥ Pineapple Orchard (PO) ≥ Coconut Plantation (CP)≥ Oil Palm Plantation (OPP), followed by silt :WD ≥ CP≥ PO ≥ OPP and clay: OPP≥CP≥PO≥WD. Land use systems recorded serious negative effects on soil physicochemical properties, with soil pH ranging between 3.43-7.20, waste dumpsite having neutral and others having less than 6.5-8.5 as the critical limit. The mean values of potentially toxic elements in soils as regard land use systems: Ni, Mn, Fe, Cr, Zn, Pb and Cu were all above the critical limits rendering the soil polluted. The effects of Land-use systems on biochemical indicators of soil degradation ranged from None to slightly (1) -Very highly degraded soils (4), with organic matter (OM) as biological indicator dominating the index. The effect of land use systems on soil degradation was in decreasing trend: WD > CP >OPP> PO constituting 32.5%, 26.7%, 20.8% and 20% respectively. Integrated waste management (IWM) and smart farming techniques should be encouraged for soil quality improvement.

Dispersant-enhanced migration of radiocesium among soil size fractions: A novel strategy for volume reduction of radioactively contaminated soil

In the aftermath of the Fukushima Daiichi Nuclear Power Plant accident, a pioneering large-scale decontamination project was initiated, aiming to enable the return of evacuees. This project, the first of its kind in human history, involved the transportation of soils collected during decontamination to interim storage facilities. Before recycling or disposal, these soils undergo processes like volume reduction. However, there's a need for innovative methods to reduce volume effectively and treat secondary wastes more efficiently. The current study explores the impact of a dispersant, sodium hexametaphosphate (SHMP), on the behavior of radiocesium (r-Cs: 137Cs) dynamics in different size fractions of radioactively contaminated soils from Fukushima. The solid-phase speciation analysis of Fukushima soils validated that at least 50% of the 137Cs or other minerals are associated with difficult-to-extract soil phases. Nonetheless, the low 137Cs/133Cs ratio in corresponding soil phases implies a slower r-Cs fixation mechanism. The wet-sieving of r-Cs contaminated soil fraction, < 2 mm, with SHMP, resulted in different soil subfractions (2000–212, 212–53, and < 53 μm). Following SHMP treatment, dispersion of > 92% of 137Cs associated with < 212 μm soil size fractions was observed. The migration of 137Cs towards smaller soil size fractions can be attributed to either SHMP-induced cation exchange or the formation of polyvalent complexes involving SHMP and soil minerals. The condensation of 137Cs in < 212 μm, as induced by SHMP, enabled the subsequent reuse of the larger soil fraction (> 212 μm), which was less contaminated. This study provides a new perspective on the effects of dispersants and contributes to a better understanding of the complex interactions among organic carbon, 137Cs, monovalent and polyvalent cations, and soil functional groups concerning the volume reduction of soils contaminated with r-Cs.

A comparative study of the pyrolysis and hydrolysis conversion of tire

In the present study, we pyrolyzed a waste tire at various temperatures under an N2 atmosphere and a water environment in an autoclave reactor to investigate the effect of water on tire degradation. The analysis involved a comparison of product distribution, char properties, oil composition, and the behavior of heteroatom elements (especially oxygen, nitrogen, and sulfur) under different atmospheres. Elemental analysis, functional-group identification, and chemical state analysis of sulfur were performed for chars. In addition, the chemical composition, elemental composition, and molecular weight of the produced oils were evaluated. The heavy fraction of oils, not detectable by gas chromatography-mass spectrometry (GC-MS), was analyzed through Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The findings revealed that high temperatures promoted oil cracking, resulting in the formation of light oils in both pyrolysis and hydrolysis processes. Compared to pyrolysis, hydrolysis generated a higher yield of low molecular–weight oil. Elevated hydrolysis temperatures promoted aromatization, yielding an oil with a low H/C ratio and a high double bond equivalent number. Consequently, the concentration of aromatics in the light fraction of oils generated from the hydrolysis process exceeded that in oils from the pyrolysis process. Temperature exhibited a limited impact on oil composition during the pyrolysis process. Hydrolysis promoted the release of heteroatom-containing compounds at low temperatures. During pyrolysis, nitrogen was gradually released from the solid phase, whereas nitrogen-containing compounds were released early during hydrolysis, with gas-phase nitrogen accounting for more than 50 wt% at 320 °C. A maximum D-limonene yield of 45.58% was obtained at 360 °C within 0 min of hydrolysis, with the potential conversion of D-limonene into aromatics at higher hydrolysis temperatures. These results contribute to the understanding of tire valorization via hydrolysis.

Study on the influence of SARA fraction in heavy oil on the oil recovery during water flooding by experiments and the molecular dynamics simulation

W/O emulsification in the J-7 reservoir has been regarded as the main reason for enhancing oil recovery. Therefore, in this article, the chemical structures of SARA fractions of JD-1 crude oil were obtained through characterization experiments, and the effect of the influence of SARA fractions on the W/O emulsification and the oil recovery by using emulsification experiments, interfacial experiments, emulsification experiments, and water flooding experiments. Results showed from emulsification experiments that the emulsification degree of the simulated oil containing asphaltenes was higher than other simulated oils. All emulsions of SARA fractions after emulsifying were W/O emulsions, but compared with other components, the performance of emulsions of asphaltenes was the best. The viscosity of emulsions reached 8.16–18.38 times that of simulated oil, the average size of was only 0.68 μm, and the stability was also very good. From interface tension and expansion modulus experiments, it can be seen that after adding asphaltenes, the decrease degree of interface tension and the increased degree of expansion modulus were the most. The result of molecules dynamic simulations showed that the adsorption force on the oil-water interface of asphaltenes was greater than other components. The water flooding experiments found the recovery of the simulated oil containing asphaltenes reached 43.81%, which was higher than other simulated oil, indicating that the easier W/O emulsification was formed, the recovery rate was higher.

COMPARATIVE ANALYSIS OF CHEMICAL COMPOSITION OF THYMUS SERPYLLUM L. AND THYMUS MARSCHALLIANUS WILLD. ESSENTIAL OILS BY GAS-LIQUID CHROMATOGRAPHY WITH MASS SPECTROMETRY DETECTION

Introduction. Plant essential oils are natural sources of the different compounds, the action of which in the macroorganism is determined by their chemical composition, depending on environmental factors, including plant species. Aim. The aim of the study was to compare the chemical composition of essential oils, obtained from the aerial parts of Thymus serpyllum L. and Thymus marschallianus Willd. (Lamiaceae). Material and methods. The plant raw materials of Thymus marschallianus were collected in the flowering phase in the Saratov region in June, the plant raw materials of Thymus serpyllum were purchased in the pharmacy network. The essential oils were obtained by Ginsberg’s steam hydrodistillation method. Analysis of their chemical composition was performed by gas-liquid chromatography with mass spectrometry detection. Results. The main components of both types of the essential oils were represented by thymol and its isomers, their mass fraction in the essential oil of T. marschallianus is 38.4, in the essential oil of T. serpyllum is 44%. The comparative analysis was carried out using the non-parametric Mann-Whitney criterion. Statistically significant differences with 95% probability were established for tricyclic sesquiterpene alkenes, the total content of which in the essential oil of T. marschallianus is 4.73%, in the essential oil of T. serpyllum – 3.59%. Conclusion. According to their chemical composition the essential oils of the mentioned plant species belong to phenolic chemotype and are similar in the major compounds.