Yuliya Yurievna Petrova

Comparative efficiency of three surfactants for washing motor oil-contaminated soil | Ryumin | Proceedings of Universities. Applied Chemistry and Biotechnology Сравнительный анализ моющей способности трех поверхностно-активных веществ при очистке почв, загрязненных моторным маслом | Рюмин | Известия вузов. Прикладная химия и биотехнология

Влияние нефти на критическую концентрацию мицеллообразования поверхностно-активных веществ

Chemical and biological approaches are widely applied to assess petroleum hydrocarbon contamination in soils; however, their results are often difficult to compare due to the use of fundamentally different extraction media. Chemical analytical methods typically rely on non-polar organic solvents, whereas biological toxicity assessments are based on aqueous soil extracts, reflecting water-soluble fractions of contaminants. This methodological discrepancy complicates the integrated evaluation of soil contamination and the assessment of remediation effectiveness. This study proposes an FTIR-based approach for assessing petroleum hydrocarbon contamination in sandy podzolic soil based on extraction with aqueous dimethyl sulfoxide (DMSO). The proposed method aims to reduce the methodological gap between classical chemical monitoring and aqueous-based biological assessment frameworks. The extraction performance of distilled water and aqueous DMSO solutions with different concentrations was evaluated using model soil samples artificially contaminated with crude oil. Crude oil was used as a multicomponent contaminant, whereas “petroleum hydrocarbons” refers to the operationally defined hydrocarbon fraction extracted from the soil–oil system and detected by FTIR in the C–H stretching region. Hydrocarbon extraction efficiency was assessed based on characteristic C–H stretching absorption bands in the 2800–3100 cm⁻¹ infrared region. Distilled water exhibited limited extraction capacity and rapidly reached saturation, resulting in weak and concentration-independent absorption responses. In contrast, aqueous DMSO increased the apparent solubility of hydrocarbons and yielded reproducible, concentration-dependent spectral responses. A 75% (v/v) aqueous DMSO solution was selected as a practical compromise extraction medium, increasing analytical sensitivity while remaining more compatible with aqueous conditions than conventional non-polar organic solvents. The proposed method provides a lower-hazard and methodologically coherent extraction approach for FTIR-based chemical monitoring of petroleum-contaminated soils and may facilitate improved comparability between chemical measurements and aqueous-based biological assessment approaches in integrated soil contamination and remediation studies.

The experimental study deals with the formation of multicomponent microdroplets with a size of 110–210 μm in a double-emulsion flow-focusing microfluidic chip by the squeezing mechanism during the interaction of three liquids. They include aqueous solutions of sodium alginate (shell) and beef gelatin with the addition of common thyme extract (core), as well as sunflower oil. A physical and mathematical energy and mass conservation-based model was developed to predict the diameter of a multicomponent liquid microdroplet, Dd. As a result of modeling, the factors defining Dd were explored, on the basis of which an empirical model rose from the capillary number for the oil phase (Cao≈ 0.05–0.15) was proposed and verified. Empirical modeling of nanodosing characteristics revealed the multiscale influence of the flow rates of the three liquids involved and the concentrations of sodium alginate and thyme extract. The practical significance of the modeling is reflected by the correlation of the values of Dd with the nanodoses of biologically active substances with complex pharmacological effects, which were calculated using high-performance liquid chromatography of thyme extract. The feasibility of encapsulating aqueous thyme extract to create biologically active microsystems was confirmed.

Contamination of gray forest soils with oil and diesel fuel in concentrations of 50, 150, and 300 mL/kg led to a decrease in the soil capillary moisture capacity. With the introduction of 50 mL of oil per kilogram of soil, this indicator decreased from 62 (corresponding to the best capillary moisture capacity) to 22.6%; for 150 mL/kg, down to 19.1%; and for 300 mL/kg, down to 12.6%. The effect of diesel fuel on the capillary moisture capacity of the soil was similar. At 50, 150, and 300 mL of diesel fuel per kilogram of soil, the capillary moisture capacity decreased from 62% down to 28.3, 20.0, and 13.8%, respectively. After applying the microbial oil-destroying preparation “DOP-UNI” and subsequent exposure for three weeks, it was possible to restore this agrophysical characteristic in part. Even for such a short exposure time, the capillary moisture capacity of the soil contaminated with oil (50–300 mL/kg) increased by 1.3–1.8 times after treatment with the biopreparation compared to the untreated oil-contaminated sample. However, the soil capillary moisture capacity still remained lower than in uncontaminated (control) soil samples. A similar trend was noted in the experiment with diesel fuel. In addition, the treatment of oil-contaminated soil with the biopreparation “DOP-UNI” for three weeks led to a decrease (by about 20%) in phytotoxicity at an oil contamination level of up to 150 g/kg. The data obtained allow us to suggest prospects for using the biopreparation “DOP-UNI” for remediation of soils contaminated with oil products and for restoration of their agrophysical properties. At the same time, lowering the temperature down to 10°C in the experiment did not have a significant effect on the efficiency of the biopreparation, at least during the 3-week experiments. This indicates that it is possible to use “DOP-UNI” at low temperatures, which is typical for the main oil fields in the Russian Federation.

The contamination of gray forest soils with oil and diesel fuel at concentrations of 50, 150 and 300 ml/kg is shown to lead to a decrease in their capillary moisture capacity. When applying 50, 150 and 300 ml/kg of oil, this indicator decreased from 62 (corresponds to the best capillary moisture capacity) down to 22.6, 19.1 and 12.6%, respectively. The effect of diesel fuel on the capillary moisture capacity of the soil was similar. In the presence of 50, 150 and 300 ml/kg of this oil product, the capillary moisture capacity of the soil decreased from 62% down to 28.3, 20.0 and 13.8%, respectively. As a result of the introduction of the microbial oil-destroying preparation “DOP-UNI” and subsequent exposure for 3 weeks, it was possible to partially restore this agrophysical characteristic of the soil. Even during such a short exposure time, the capillary moisture capacity of the oil-contaminated soil (50–300 ml/kg), after treatment with the biological preparation, increased by 1.3–1.8 times compared to an untreated oil-contaminated sample. However, its values still remained lower than in uncontaminated soil samples. A similar trend was noted in our experiment with diesel fuel. In addition, the treatment of oil-contaminated soil with the biological preparation “DOP-UNI” for 3 weeks led to a decrease (by ~20%) in phytotoxicity at the level of oil contamination up to 150 g/kg. The obtained data allow us to judge the prospects of using the biopreparation “DOP-UNI” for soil remediation in the case of contamination with petroleum products and restoration of their agrophysical properties. At the same time, lowering the temperature down to 10°C did not significantly affect the effectiveness of the biopreparation, at least in the described 3-week experiments. This indicates the possibility of its use in low-temperature conditions, which is typical for the main oil production sites in the Russian Federation.

The study was aimed at comparing the effect of oil, diesel fuel, and motor oil on the capillary moisture capacity and hygroscopic moisture content of gray forest soil, as well as assessing changes in these characteristics of oil-contaminated soils following their washing with polysorbate 80. Water and a washing solution (with detergent concentrations of 1, 5, and 10 g/L) were added to the soil to be continuously mixed for 1 h at 20 °С using a shaker (60 rpm). The analyzed agrophysical characteristics of soils are shown to decrease when soils are contaminated with oil, diesel fuel, and motor oil at concentrations of 50, 150, and 300 mL/kg. The effect of motor oil on capillary moisture capacity is more pronounced than those of oil and diesel fuel at similar concentrations, while the effect on hygroscopic moisture content is, conversely, less pronounced. The washing of contaminated soils with polysorbate 80 partially restored these agrophysical characteristics; however, they remained lower than those of the original samples. The effectiveness of polysorbate 80 is also confirmed by the reduction in the phytotoxicity of contaminated soil samples following their washing with detergent solutions. At the level of oil contamination of up to 150 mL/kg, solutions containing 5 g/L of polysorbate 80 were found to be more effective, whereas at 300 mL/kg, it is recommended to increase the concentration of detergent up to 10 g/L. The recommended weight ratio of soil, washing solution, and water for soil washing is 1:1:4. Thus, the prospects for using polysorbate 80 to mitigate the negative impact of oil contamination in soil are demonstrated.

The goal of the research was to evaluate the effect of a protective coating for tomatoes enriched with Melilotus officinalis extracts with pronounced antioxidant activity. The Methods. The extraction conditions were optimized: the dried plant material was ground to a particle size of 0.2-0.5 mm, the raw material to extractant ratio was 1:100, and the extraction time was 5 days. The content of phenolic compounds, flavonoids, and antioxidant activity of the extracts were determined by spectrophotometric methods. The Results. The extracts obtained using 10% and 50% ethyl alcohol demonstrated a high content of phenols (33.7 mg/g) and flavonoids (1.74 mg/g), respectively. The highest antioxidant activity (89.8%) was recorded in the extract obtained with 50% ethyl alcohol. The study of the effect of the protective coating on the preservation of tomatoes showed that during storage without cooling, the daily weight loss was 1.1±0.1% for uncoated samples and 0.9±0.1% for coated samples. During refrigeration storage, the weight loss was less pronounced: after 7 days, the difference between the samples with and without the coating was 0.7%. During the first 3 days of storage, the weight of the tomatoes decreased uniformly for all samples, but starting from the 4th day, the uncoated tomatoes began to lose weight much faster compared to the samples treated with a protective coating. The coating with the addition of extracts demonstrated the greatest efficiency: the weight loss without cooling and in a cooled state was 5.7% and 1.7%, respectively, while for tomatoes without coating, these figures were 7.3% and 2.3%. Conclusion. The data obtained indicate the potential of using protective coatings with Melilotus officinalis extracts to increase the shelf life of tomatoes and reduce weight loss.

This study examines the effects of oil contamination on three soil types—podzolic, sod-gley, and alluvial—in Western Siberia’s middle taiga, assessing key physical and chemical properties and the influence of the surfactant Modified Syntherol (MS) on oil degradation. In controlled laboratory experiments, oil was introduced at 50, 100, and 150 g/kg concentrations. Results indicate a substantial increase in soil pH, most notably in podzolic soils, alongside a significant decline in cation exchange capacity (CEC). For example, CEC in podzolic soils dropped five-fold at higher contamination levels, reflecting a reduced ability to retain essential nutrients. The water retention capacity decreased in all soil types, with the most pronounced decline observed in alluvial soils’ capillary moisture levels. MS application did not accelerate oil degradation; even after 35 days, natural decomposition rates in untreated soils remained low (0.02–0.4%), underscoring the persistence of oil contaminants. Notably, podzolic soils showed the highest susceptibility to oil contamination due to their acidic and low-organic nature, in contrast to sod-gley and alluvial soils, which demonstrated moderate resilience. These findings highlight the need for soil-specific remediation approaches, as general methods may be ineffective for soils with differing vulnerabilities and recovery capacities. This research provides essential insights for developing effective, tailored strategies to address the environmental challenges of oil pollution, advancing sustainable soil management practices for sensitive taiga ecosystems.

The operation of biofuel cells (BFC) based on the Micrococcus luteus 1-i strain under the action of the main representatives of various groups of surfactants has been analyzed. The following were tested: cetyltrimethylammonium bromide (cationic surfactant), Tween-80 (non-ionic surfactant), sodium lauryl sulfate (anionic surfactant). It was shown that cetyltrimethylammonium bromide reduced the electrical characteristics of BFC at concentrations of 10 mg/L, Tween-80—from 5 mL/L, sodium lauryl sulfate—from 100 mg/L. A comparison of the electrogenic activity of bacteria in BFCs with their viability and the kinetics of the redox potential of the anolyte allowed us to conclude that the decrease in the efficiency of the studied BFCs under the influence of surfactants in the tested concentration ranges is associated with their toxic effect on microbial cells.