Search Results (7,272)

The potential of biochar to mediate shifts in soil microbial communities caused by polycyclic aromatic hydrocarbon (PAH) stress in farmland, thus assisting in the bioremediation of contaminated soil, remains uncertain. This study introduced wheat straw biochars generated at 300 °C (W300) and 500 °C (W500) at varying levels (1% and 2% w/w) into agricultural soil contaminated with phenanthrene at 2.5 and 25 mg/kg. The aim was to investigate their effects on microbial community structure and phenanthrene degradation by indigenous microbes. Biochar application in both slightly (PLS) and heavily (PHS) contaminated soils increased overall microbial/bacterial biomass, preserved bacterial diversity, and selectively enriched certain bacterial genera, which were suppressed by phenanthrene stress, through sorption enhancement and biotoxicity alleviation. The abundances of PAH-degrading genera and nidA degradation gene were promoted by biochar, especially W300, in PHS due to soil nutrient improvement, enhancing phenanthrene biodegradation. However, in PLS, biochar, particularly W500, inhibited their abundance due to a reduction in phenanthrene bioavailability to specific degraders, thus hindering phenanthrene biodegradation. These findings suggest that applying wheat straw biochar produced at appropriate temperatures can benefit soil microbial ecology and facilitate PAH elimination, offering a sustainable strategy for utilizing straw resources and safeguarding soil health and agricultural product quality. Full article

Spent ion exchange resins were subjected to hydrothermal carbonization (HTC) and physical activation to produce adsorbents, which were tested for the adsorption of bisphenol A (BPA) and sodium diclofenac (DCF) in water. PAHF0.35.WV and PAHF0.50.WV were the materials that presented the largest specific surface area, around 200 m²/g. The best performance was in the adsorption of BPA, with an adsorption capacity of 24.45 and 23.34 mg/g. The kinetic and adsorption isotherm models that presented the best adjustments of the curves to the experimental data were the pseudo-second-order model and the Freundlich model. The maximum adsorption capacity of DCF was 17.82 mg/g for PAHF0.35.WV and 15 mg/g for PAHF0.50.WV. The best fit of the adsorption kinetic curves to the experimental data was for the pseudo-second-order model. In the adsorption isotherms, the Langmuir and Freundlich models presented the best fit. The toxicity study with the microalgae Raphidocelis subcapitata did not demonstrate any toxic effects of the adsorbents. Material regeneration tests indicated a recovery of the adsorption capacity of around 50% in the first cycle, and from the second cycle onwards, the recovery was not satisfactory. However, the results indicate that the anionic resin residue has potential for use in the production of activated hydrocarbons. Full article

This study investigates the composition, abundance, and vertical export of polycyclic aromatic hydrocarbons (PAHs) across three deep basins of the northeastern Mediterranean Sea (NEMS) over one year. Sinking particles were collected using sediment traps, and PAH analysis was conducted via gas chromatography-mass spectrometry. PAH fluxes varied significantly, peaking in the north Aegean Sea due to mesotrophic conditions, nutrient-rich riverine and Black Sea water inflows, and maritime anthropogenic inputs. The fluxes were highest in winter and lowest in fall. In the Cretan Sea, petrogenic sources (~70%) dominated, driven by currents, with fluxes highest in spring and lowest in winter. The Ionian Sea exhibited lower fluxes, peaking in summer and decreasing in fall. Atmospheric deposition seems to be the main transport pathway of pyrolytic PAHs in this site, while its high-water column depth (4300 m) compared to the other sites presumably enables extended degradation of organic constituents during particle settling. The positive matrix factorization (PMF) and principal component analysis (PCA) results reveal complementary insights into PAH sources and transport mechanisms. PMF analysis identified combustion (61%) and petrogenic (22%) sources, while PCA highlighted biogenic fluxes (57.7%) and atmospheric deposition. Seasonal productivity, riverine inputs, and water circulation shaped PAH variability, linking combustion-related PAHs to atmospheric soot and petrogenic PAHs to organic-rich particles. Full article

Dolomitization is a critical diagenetic alteration that impacts the formation of carbonate hydrocarbon reservoirs. In the offshore Bohai Bay Basin, the Lower Paleozoic carbonate reservoirs in buried hill traps, and the basement highs unconformably overlain by younger rock units, are emerging as a prospective target and predominantly occur in dolomite layers. Meanwhile, the formation mechanisms of the dolomite are not clear, which affects the understanding of the occurrence of deep dolomite reservoirs and hinders oil and gas exploration. Based on comprehensive observations of the thin sections of the carbonate samples, the dolomite types were meticulously categorized into micritic dolostone, fine-crystalline dolostone, and saddle dolomite. Then, carbon, oxygen, and strontium isotope and trace elements were examined to elucidate the dolomitization fluids and propose diagenetic models for the three kinds of dolomite formation. The mineralogical and geochemical evidence reveals that there were two kinds of dolomitization fluids, including penecontemporaneous seawater, and hydrothermal fluid. The diagenetic fluid of the micritic dolostone and fine-crystalline dolostone both involved penecontemporaneous seawater, but fine-crystalline dolostone is also affected by later burial dolomitization processes. The saddle dolomite, filling in pre-existing fractures or dissolution pore cavities, is attributed to a hydrothermal fluid associated with magmatic activities. Notably, the extensive layered fine-crystalline dolostone was the predominant reservoir rock. The initial mechanism for its formation involves penecontemporaneous seepage reflux dolomitization, which is superimposed by later burial dolomitization. The burial dolomitization enhanced porosity, subsequently facilitating the formation of a fracture-related dissolution pore cavity system, and partly filled by saddle dolomite during the Cenozoic hydrothermal events. The findings highlight that the layered fine-crystalline dolostone that underwent multiphase dolomitization is the most potential target for hydrocarbon exploration. Full article

2-Methylfuran (2-MF) has emerged as a promising renewable alternative fuel, primarily due to its sustainable production processes and its potential to significantly reduce soot emissions. However, when blended with diesel, it presents challenges, including an increase in NOx emissions, which is attributed to the lower cetane number (CN) of the M30 blend. This study investigates the effect of adding 2-ethylhexyl nitrate (2-EHN), a cetane enhancer, to the M30 blend (30% 2-MF by volume), on combustion characteristics and exhaust emissions. Experiments were conducted using a modified four-cylinder, four-stroke, direct-injection compression ignition (DICI) engine featuring a common rail fuel injection system. The engine was evaluated under different load conditions, with brake mean effective pressure (BMEP) ranging from 0.13 to 1.13 MPa, while maintaining a constant engine speed of 1800 rpm. The incorporation of 1.5% and 2.5% 2-EHN into the M30 blend enhanced combustion performance, as indicated by a reduction in the maximum pressure rise rate, a shorter ignition delay (ID), and an extended combustion duration (CD). Furthermore, the brake-specific fuel consumption (BSFC) reduced by 2.78% and 5.7%, while the brake thermal efficiency (BTE) increased by 3.54% and 7.1%, respectively. Moreover, the inclusion of 2-EHN led to a significant reduction in Nox by 9.20–17.57%, with the most significant reduction observed at a 2.5% 2-EHN, where hydrocarbon (HC) decreased by 7.93–21.59%, and carbon monoxide (CO) reduced by 12.11–33.98% as compared to the M30 blend without 2-EHN. Although a slight increase in soot emissions was observed with higher concentrations of 2-EHN, soot levels remained significantly lower than those from pure diesel. The results indicate that the addition of 2-EHN can effectively mitigate the trade-off between NOx and soot emissions in low cetane number oxygenated fuels. Full article

Plastic waste (PW) presents a significant environmental challenge due to its persistent accumulation and harmful effects on ecosystems. According to the United Nations Environment Program (UNEP), global plastic production in 2024 is estimated to reach approximately 500 million tons. Without effective intervention, most of this plastic is expected to become waste, potentially resulting in billions of tons of accumulated PW by 2060. This study explores innovative approaches to convert PW into high-value carbon nanomaterials (CNMs) such as graphene, carbon nanotubes (CNTs), and other advanced carbon structures. Various methods including pyrolysis, arc discharge, catalytic degradation, and laser ablation have been investigated in transforming PW into CNMs. However, four primary methodologies are discussed herein: thermal decomposition, chemical vapor deposition (CVD), flash joule heating (FJH), and stepwise conversion. The scalability of the pathways discussed for industrial applications varies significantly. Thermal decomposition, particularly pyrolysis, is highly scalable due to its straightforward setup and cost-effective operation, making it suitable for large-scale waste processing plants. It also produces fuel byproducts that can be used as an alternative energy source, promoting the concept of energy recovery and circular economy. CVD, while producing high-quality carbon materials, is less scalable due to the high cost and required complex equipment, catalyst, high temperature, and pressure, which limits its use to specialized applications. FJH offers rapid synthesis of high-quality graphene using an economically viable technique that can also generate valuable products such as green hydrogen, carbon oligomers, and light hydrocarbons. However, it still requires optimization for industrial throughput. Stepwise conversion, involving multiple stages, can be challenging to scale due to higher operational complexity and cost, but it offers precise control over material properties for niche applications. This research demonstrates the growing potential of upcycling PW into valuable materials that align with global sustainability goals including industry, innovation, and infrastructure (Goal 9), sustainable cities and communities (Goal 11), and responsible consumption and production (Goal 12). The findings underscore the need for enhanced recycling infrastructure and policy frameworks to support the shift toward a circular economy and mitigate the global plastic crisis. Full article

The pheromones of crane flies (Tipulidae), one of the largest families within the order Diptera (over 15,000 species), are unknown. The aim of our study was to identify the chemical compounds involved in communication in Tipula autumnalis, a representative species of the family. Female cuticular washes were found to be attractive to males in a bioassay. GC-EAD analysis revealed nine EAG-active compounds, which were identified as cuticular hydrocarbons (CHCs). Both males and females contained these CHCs, though in different ratios. The strongest antennal responses in male T. autumnalis were evoked by n-pentacosane, (Z)-9-pentacosene, and (Z, E)-6,9-pentacosadiene, which were the predominant components in females. Each of these compounds were attractive to males in the behavioral assay and are therefore attributed to the female sex pheromone of T. autumnalis. (Z)-9-tricosene and (R)-3-methylheneicosane elicited both EAG and behavioral responses in males and were abundant in washes from same-sex individuals. In addition to the compounds involved in female–male interactions, it is evident that T. autumnalis also employs CHCs in male–male interactions. The exact roles of some compounds remain undetermined. Among the semiochemicals, the established stereostructure of (Z, E)-6,9-pentacosadiene and the olfactory/behavioral effects of (R)- and (S)-3-methylheneicosane were novel findings in insects. Full article

The application of persulfate (PS) for the remediation of petroleum hydrocarbon contamination is among the most widely employed in situ chemical oxidation (ISCO) techniques, and it has received widespread attention due to its limited impact on soil integrity. This study employed a FeSO₄-activated PS oxidation method to investigate the feasibility of remediating soil contaminated with total petroleum hydrocarbons (TPHs). The factors tested included the TPH concentration, different PS:FeSO₄ ratios, the reaction time for remediation, soil physical and chemical property changes before and after remediation, and the effect of soil before and after remediation on soybean growth. The TPH degradation rate in soil was highest for high-, medium-, and low-TPHs soils—81.5%, 81.4%, and 72.9%, respectively, with minimal disruption to the soil’s physicochemical properties—when PS:FeSO₄ = 1:1. The remediation verification results indicated that the condition of the soybeans was optimal when PS:FeSO₄ = 1:1. Under this condition, the net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, and transpiration rate all remained high. Therefore, the best remediation effect was achieved with PS:FeSO₄ = 1:1, which also minimized the damage to the soil and the effects on crop growth. Full article

The measurement of atmospheric deposition fluxes is an excellent tool for assessing the contamination of territory and the subsequent exposure of the population to major contaminants through the food chain. In this context, the aim of this study was to measure the polycyclic aromatic hydrocarbon (PAH) deposition fluxes in the city of Rome (ISS Station) during the year 2022/2023 at two different heights above the ground (vertical profile), in order to evaluate the influence that the vertical profile has on PAH deposition. Two measuring positions were identified, one at street level and one at a height of 20 m. The collection of bulk atmospheric depositions was carried out approximately every 30 days, and the PAHs were determined according to the indications given in ISTISAN Report 06/38 and Standard UNI EN 15980:2011. The results show that throughout the year, the deposition rates of settleable dust were always higher at the lower (annual average of 48.5 mg m⁻² day⁻¹) collection position than at the higher position (annual average of 17.5 mg m⁻² day⁻¹). Despite this difference, the concentrations and profiles of the main PAHs analyzed, as indicated in EU Directive 2024/2881, in the dust collected at the two positions were almost similar, showing that the vertical profile did not influence the composition and concentration of PAHs in the collected settleable dust. Furthermore, a comparison of the deposition rates of sedimentable dust and PAHs with the legislative references currently present in Europe was made, highlighting that in the city of Rome during the monitoring period of this study, the values of dust and PAHs were lower than the limit and guide values and were also in line with other Italian urban locations. Full article

The oil and gas industry’s view of water production, once regarded primarily as a waste stream, has shifted in recent years due to the growing environmental and economic challenges. Industries now recognize the substantial volumes of water produced during production operations and are actively exploring alternative water management strategies. Among these, water treatment stands out as a leading approach, aimed at purifying the water to achieve specific element concentrations suited for targeted applications. The produced water from oil and gas reservoirs is a complex mixture of various organic and inorganic compounds, as well as dissolved and suspended solids. It is considered a highly contaminated waste stream, making effective treatment essential to meet future critical water demand. The physical and chemical properties of the produced water vary depending on the extraction location, geological formations, and type of hydrocarbon produced. This review examines multiple treatment methods used for the beneficial reuse of produced water, covering physical, chemical, and biological techniques, along with examples demonstrating their effectiveness in field case studies. Full article

This review explores biochar’s potential as a sustainable and cost-effective solution for remediating organic pollutants, particularly polycyclic aromatic hydrocarbons (PAHs) and pesticides, in water. Biochar, a carbon-rich material produced from biomass pyrolysis, has demonstrated adsorption efficiencies exceeding 90% under optimal conditions, depending on the feedstock type, pyrolysis temperature, and functionalization. High surface area (up to 1500 m²/g), porosity, and modifiable surface functional groups make biochar effective in adsorbing a wide range of contaminants, including toxic metals, organic pollutants, and nutrients. Recent advancements in biochar production, such as chemical activation and post-treatment modifications, have enhanced adsorption capacities, with engineered biochar achieving superior performance in treating industrial, municipal, and agricultural effluents. However, scaling up biochar applications from laboratory research to field-scale wastewater treatment poses significant challenges. These include inconsistencies in adsorption performance under variable environmental conditions, the high cost of large-scale biochar production, logistical challenges in handling and deploying biochar at scale, and the need for integration with existing treatment systems. Such challenges impact the practical implementation of biochar-based remediation technologies, requiring further investigation into cost-effective production methods, long-term performance assessments, and field-level optimization strategies. This review underscores the importance of addressing these barriers and highlights biochar’s potential to offer a sustainable, environmentally friendly, and economically viable solution for large-scale wastewater treatment. Full article

This study aims to address the limited understanding of wash oil degradation in benzene units by analysing changes in the composition and properties of fresh and operating oils from different manufacturers. The findings will provide insights into the degradation pathways and stability of these oils. Gas chromatography/mass spectrometry was used to analyse the provided samples, and the dynamic viscosity of the oils was determined using a Brookfield LV DV2T rotational viscometer. During operation, the “heavy” oil (HO) becomes less volatile, while the ”light” oil (LO) becomes slightly more volatile. The viscosity of the HO increases 1.25 times during operation. The LO is characterised by a higher total concentration of alkyl derivatives (48 wt.% compared to 44 wt.% for the HO). LO is enriched with naphthalene and indene, while HO loses 1- and 2-methylnaphthalenes and shows an increase in the concentrations of dibenzofuran, fluorene, anthracene, and phenanthrene. The oxidation products of LO include oxidised alkyl groups, while HO shows oxidised non-substituted hydrocarbons. The practical value of such studies lies in guiding the selection of fresh oil under current operating conditions. LO is more resistant to degradation as an absorbent than heavier wash oil. Full article

Volatile and semi-volatile compounds, such as petroleum hydrocarbons and equipment lubricating oils, often contaminate soil due to accidents, posing significant ecological and health risks. Traditional soil remediation methods, such as thermal desorption and bioremediation, are time-consuming and resource-intensive, prompting researchers to explore more efficient alternatives. This study investigates the effectiveness of an in situ reactor for microwave-assisted soil remediation, specifically focusing on the impact of soil type and moisture content on pollutant removal efficiency. The reactor, designed to operate within a modified household microwave oven, provides direct microwave irradiation to the soil surface, enabling precise control of heating conditions. Experiments were conducted using soil samples of varying particle sizes and moisture levels under standardized conditions (1000 W microwave power, 2.45 GHz frequency). The results show that moisture content plays a critical role in pollutant removal efficiency, with an optimal moisture content of 10 wt % enhancing microwave absorption and energy transfer, thus improving pollutant recovery. In comparison with traditional resistive heating, microwave heating achieved a faster temperature rise and higher final temperatures, significantly improving pollutant removal efficiency in a shorter time frame. This study highlights the advantages of microwave heating, including its superior energy efficiency, faster pollutant volatilization, and the potential for optimized soil remediation in real-world applications. These findings provide valuable insights for the development of more sustainable and efficient soil remediation technologies. Full article

In geoenergy science and engineering, well placement optimization is the process of determining optimal well locations and configurations to maximize economic value while considering geological, engineering, economic, and environmental constraints. This complex multi-million-dollar problem involves optimizing multiple parameters using computationally intensive reservoir simulations, often employing advanced algorithms such as optimization algorithms and machine/deep learning techniques to find near-optimal solutions efficiently while accounting for uncertainties and risks. This study proposes a hybrid workflow for determining the locations of production wells during primary oil recovery using a multi-modal convolutional neural network (M-CNN) integrated with an evolutionary optimization algorithm. The particle swarm optimization algorithm provides the M-CNN with full-physics reservoir simulation results as learning data correlating an arbitrary well location and its cumulative oil production. The M-CNN learns the correlation between near-wellbore spatial properties (e.g., porosity, permeability, pressure, and saturation) and cumulative oil production as inputs and output, respectively. The learned M-CNN predicts oil productivity at every candidate well location and selects qualified well placement scenarios. The prediction performance of the M-CNN for hydrocarbon-prolific regions is improved by adding qualified scenarios to the learning data and re-training the M-CNN. This iterative learning scheme enhances the suitability of the proxy for solving the problem of maximizing oil productivity. The validity of the proxy is tested with a benchmark model, UNISIM-I-D, in which four oil production wells are sequentially drilled. The M-CNN approach demonstrates remarkable consistency and alignment with full-physics reservoir simulation results. It achieves prediction accuracy within a 3% relative error margin, while significantly reducing computational costs to just 11.18% of those associated with full-physics reservoir simulations. Moreover, the M-CNN-optimized well placement strategy yields a substantial 47.40% improvement in field cumulative oil production compared to the original configuration. These findings underscore the M-CNN’s effectiveness in sequential well placement optimization, striking an optimal balance between predictive accuracy and computational efficiency. The method’s ability to dramatically reduce processing time while maintaining high accuracy makes it a valuable tool for enhancing oil field productivity and streamlining reservoir management decisions. Full article

The photoelectric Factor (PEF) log is a powerful tool for distinguishing between siliciclastic and carbonate lithofacies in well-log analysis and 2D correlations. However, its application in complex reservoirs has some challenges due to well spacing. We present a workflow to extend its capabilities into a 3D environment to characterize the Pennsylvanian Strawn and Canyon reef complex in the Salt Creek field, Kent County, West Texas. The productive zones within this reservoir are composed of porous oolitic grainstones and skeletal packstones. However, there are some porous shale beds within the reef complex that are indistinguishable from the porous limestone zones on the neutron porosity log that have posed major challenges to hydrocarbon production. To address these problems, we used a machine-learning procedure involving multiattribute analysis and probabilistic neural network (PNN) to predict photoelectric factor (PEF) volume to characterize the reservoir and identify the shale beds. By combining neutron porosity, gamma ray, and the predicted PEF logs, we found that (1) these shale beds, hereby referred to as shale-influenced carbonates, are characterized by photoelectric factor values ranging from 4 to 4.26 B/E. (2) Based on the PEF values, the least porous interval is the Canyon System, having <1% porosity and characterized by PEF values of >4.78 B/E; while the most porous interval is the Strawn System, composed mostly of zones with porosity ranging from 3% to 28%, characterized by PEF values varying from 4.26 to 4.78 B/E. Full article