Hydrocarbon Compounds Research Articles

Microbial Bioremediation of Petroleum Contaminated Soil: Structural Complexity, Degradation Dynamics and Advanced Remediation Techniques

Soil contamination with petroleum hydrocarbons poses a significant environmental challenge, necessitating effective remediation strategies to mitigate ecological risks. This review paper systematically examines the current state of knowledge regarding soil contamination with petroleum hydrocarbons, focusing on diverse sources and the extent of contamination. The investigation encompasses a range of hydrocarbon compounds, including aliphatic and aromatic fractions, emphasizing the dynamic nature of the contamination scenarios. A thorough review of bioremediation techniques, which have shown promise and sustainability as methods for cleaning up soil contaminated with petroleum hydrocarbons are also involved in order to solve these issues. Each of the three microbial processes, biodegradation, bioaugmentation, and biostimulation, is covered in detail in the paper, along with the complex mechanics underlying each technique. The report also emphasises new developments in genetics and molecular biology that add to our understanding of the metabolic pathways and microbial interactions involved in hydrocarbon breakdown. The effectiveness of plant-assisted bioremediation coupled with bioaugmentation and stimulation, specifically phytoremediation, is also explored, emphasizing the potential of certain plant species to enhance the removal of petroleum hydrocarbons from contaminated soils through rhizosphere interactions and plant-associated microbial activities. Furthermore, the paper evaluates the influence of environmental variables including soil composition, temperature, and moisture content on the effectiveness of bioremediation techniques, offering valuable perspectives on enhancing remediation efficiency through optimal conditions. The possibility for enhancing conventional bioremediation techniques through the incorporation of cutting-edge technology like nano-remediation is also explored.

Octane Response of Gasoline Fuels to Different Anti-knock Oxygenates Addition

Abstract A series of renewable and clean oxygenated compounds possessing high octane numbers, including alcohols, ethers, esters and furans, were used as octane boosters for gasoline fuels, and the octane responses of the gasoline fuels to these oxygenates addition were evaluated. Gasoline model fuels of different typical hydrocarbon compounds, including iso-octane, n-heptane, toluene, diisobutylene, and cyclohexane, were designed to have the identical octane rating. The research octane number (RON) and motor octane number (MON) of the gasoline model fuels with anti-knock oxygenates addition were experimentally measured on a standard cooperative fuel research (CFR) engine. The results highlight the varied impact of anti-knock oxygenates on the octane enhancement of gasoline fuels, with 2-methylfuran exhibiting the most pronounced RON boost effect and ethanol demonstrating the strongest MON enhancement effects, and isopropyl ether and dimethyl carbonate shows the weakest RON and MON boost effects, respectively. The anti-knock enhancement effects of the oxygenated additives are dependent on gasoline fuel compositions. With the anti-knock oxygenates addition, PRF model fuel shows more significant octane enhancements, and the octane boosting effects are reduced for the gasoline model fuels containing toluene or diisobutylene, indicating an antagonistic interaction between the oxygenates and toluene/diisobutylene. By comparing the octane enhancement effects of the tested anti-knock additives, it is evident that 2-methylfuran and ethanol are the more superior anti-knock candidates for gasoline fuels.

Bio-sorption of methylene blue and production of biofuel by brown alga Cystoseira sp. collected from Neom region, Kingdom of Saudi Arabia

Abstract The risks and challenges of the NEOM project on water bodies can be somehow resolved by using Cystoseria sp., a brown-green macroalga, and natural renewable resource species, which are appealing due to their sustainability, cost-effectiveness, and eco-friendliness. Lipid was extracted from Cystoseria sp. collected from Sharma beach, Neom, Tabuk, Kingdom of Saudi Arabia. It was treated with different solvents, petroleum ether, methanol, and petroleum ether:methanol (1:1), to obtain biofuel. Petroleum ether and methanol were the most significant solvents for extractions of six different hydrocarbon compounds, followed by methanol. Tetrahydradecane 5-methyl 60.03% in petroleum ether, 59.51% in methanol, and 51.39% in petroleum ether:methanol is obtained. Removal of 10 mg·L−1 methylene blue (MB) by alga using 0.2 g·L−1 of Cystoseria sp. and its residues after methanol extract was achieved in 120 min. Zeta potential analysis of alga confirms that different negative charges on adsorbent surfaces undergo conformational change with different solvents and adsorb the positively charged MB via electrostatic interaction force. The production of bioethanol efficiency percentage from Cystoseria sp. ranges from 5% to 68.97%. Hence, Cystoseria sp. can be a renewable resource to yield biodiesel and bioethanol and eliminate MB from wastewater, maintaining environmental sustenance and economic development.

Halogenated Polycyclic Aromatic Hydrocarbon for Hole Selective Layer/Perovskite Interface Modification and Passivation for Efficient Perovskite‐Organic Tandem Solar Cells with Record Fill Factor

AbstractPerovskite whentandemed with organic photovoltaics (OPV) for double‐junctions have efficiencypotentials over 40%. However, there is still room for improvement suchas better current matching, higher fill factor, as well as lower voltage and fill factor losses in the top perovskite cell. Here weaddress the issue associated with the top perovskite cell by utilising anovel halogenated polycyclic aromatic hydrocarbon compound, 1‐naphthylammoniumchloride (NA─Cl) playing dual roles of surface modification for the hole selectivelayer (HSL) and passivation of HSL/perovskiteinterface. Results of X‐ray photoelectron spectroscopy and density functionaltheory calculations reveal that NA─Cl retains self‐assembly property for the HSLwhile demonstrating high dipole moment and polarizability. This induces asurface dipole at the HSL/perovskite interface reducing the energetic barrierfor hole extraction by 210 meV thereby enhancing voltage output and fill factorof the device. Such scheme when implemented in a high bandgap (1.78 eV)perovskite solar cell, results in a respectable efficiency of 19.7% and thehighest fill factor of 85.4% amongst those of 1.78 eV perovskite cells reported.We have also achieved 23% cell efficient monolithic perovskite‐OPV tandem withan impressive fill factor of 84%, which is the highest for perovskite‐OPVtandem cells reported to‐date.

Techno-economic and Life Cycle Assessment for the Zero-Carbon Emission Process of the Production of Methanol from VOCs

Volatile organic compounds (VOCs) are one of the major sources of air pollutants, and the efficient treatment technologies for VOCs have garnered significant attention. The conventional VOCs treatment system converts VOCs into CO2 and directly releases them into air, and it is one of the biggest challenges for carbon neutrality. This paper integrates emerging water electrolysis and carbon utilization technologies with traditional VOCs thermal conversion to produce methanol in a zero-emission approach, converting harmful hydrocarbon compounds into valuable fuel, methanol, without CO2 emission. This paper conducts a comprehensive techno-economic analysis (TEA) and life cycle assessment (LCA) to evaluate their economic and environmental impacts. The research demonstrates that under current market conditions, the treatment costs for this technology range between $5.8 and $8.8 per kilogram. However, when bio-methane is utilized as a VOCs accelerant in this project, it significantly reduces the project's carbon footprint compared to traditional VOCs treatment. It provides insight into the waste-to-worth process in a zero-carbon footprint approach

Polyaromatic hydrocarbon profile and health risk assessment of popularly consumed species of fish in Remo Zone, Ogun State, South-West Nigeria

Polyaromatic hydrocarbon (PAH) compounds are usually introduced into foods through processing methods like smoking, grilling, etc and they have been identified as potential carcinogens. This study was aimed assessing the concentrations of PAHs and evaluating the health risk associated with consumption of 3 main fish species popularly consumed in the study area. Health risk factors like daily dietary intake (DDI), carcinogenic potencies of individual PAHs (B(A)Pteq) and the excess cancer risk (ECR) induced by dietary exposure of smoked fish consumers were examined for 16 PAHs considered as priority pollutants.. The three fish species analyzed in this study: Herring (Clupea harengus), Blue Whiting (Micromesistius poutassou) and Mackerel (Scomber scombrus) samples were extracted by liquid extraction and the concentrations of 22 selected PAHs were analyzed using GC-MS. The cumulative concentrations of PAH22 and PAH16 in the three species of fish are of the order Herring > Blue wilting > Mackerels. The results from the GC-MS analysis showed a significant difference (p<0.05) in the PAH concentration detected in the fish samples collected from the five study locations. The DDI for PAH16 in smoked Herring was found to be between 0 and 0.1277 µg/day, 0 and 0.007124 µg/day for mackerel and 0 and 0.07946 µg/day for blue whiting. Most of the ECR values obtained in this work were higher than the 10-5 guideline and this calls for intense monitoring.

Development of Ethnosciene Reels of Ketapang Malay Tribe as Supplementary Learning Resources on Hydrocarbon Compounds

The habit of the Malay community in using natural materials as fuel can be integrated into chemistry teaching materials in schools. The aim of this research is to assess the validity and practicality of reels as a learning resource and to develop reels based on the ethnoscience of the Ketapang Malay tribe. The research development model used is the Three Stages Research and Development (TSRD) model, which consists of three steps: planning, development, and dissemination. Data collection techniques involve indirect communication using validation sheets and response instruments. The subjects of the research are students from SMA N 1 Sungai Laur. The results of the study indicate that the ethnoscience-based reels of the Malay tribe are valid and practical, with validity and practicality scores of 96.3% and 90.30%, respectively. The reels can be used as an independent, practical, and engaging learning resource that is relevant to students. Therefore, the validity and practicality results of the development of ethnoscience-based reels are expected to serve as an innovative and contextual alternative media for chemistry education in schools.

Personal exposure of women to PM2.5-bound PAH derivatives from cooking emissions in varied rural kitchen setups

The present study investigates the personal exposure of women to PM2.5 and associated chemical constituents such as Elemental Carbon, Organic Carbon and 63 Poly Aromatic Hydrocarbons (PAH) compounds in varied kitchen setups viz. Indoor kitchen without partition (IKWO); Indoor kitchen with partition (IKWP); Separate enclosed kitchen outside the home (SEKO); Open kitchen (OK); and Open kitchen under stairway (OK_S) of south India. The exposure to PM2.5 was found to be highest in OK_S followed by IKWP, SEKO, IKWO and OK with average concentrations of 8943.54 ± 699, 6117.80 ± 1732, 4257.85 ± 2215, 2118.07 ± 524 and 1505.89 ± 431 μg/m3, respectively. Similarly, OK_S had the greatest levels of PM2.5-bounded PAHs (∑PAH63, ∑PAH16, and BaP) due to their small size and poor ventilation. The lifetime Excess Cancer Risk (ECR) indicated the highest lifetime exposure risk per million population (400) in OK_S type of kitchens followed by IKWO (307), SEKO (151), IKWP (149), and then OK (7) using the relative potency factor (RPF) which includes nitro-PAHs as well as methyl-PAHs apart from PAHs with high molecular weight. Additionally, it was shown that the lifetime ECR of biomass fuel was six times greater than that of LPG. The current analysis recommends a complete transition to LPG and strictly avoiding open kitchens under the staircase. Thus, the findings of this study will provide valuable information to improve the quality of the indoor environment of rural houses in India.

Effective methane decomposition using spark discharge assisted laser-induced plasma: An approach based on Fourier transform infrared (FTIR) spectroscopy

The widespread utilization of fossil fuels cause to significantly elevate greenhouse gas emissions. Consequently, the developments of the innovative methods are essential to convert methane into the green energy. Recently, significant effort is made to enhance the performance of the plasma-based conversion technologies. Here, the dissociation rate of methane into heavier hydrocarbon compounds are carefully determined by making use of a hybrid laser-induced plasma (LIP) and spark discharge (SD). Fourier-transform infrared (FTIR) spectroscopy reveals a couple of characteristic peaks after laser triggering, whose intensities notably increase at higher applied voltages. The corresponding peaks indicate the formation of heavier compounds including sp and sp2 C–H stretching bonds. The findings elucidate that the methane decomposition rate notably elevates in favor of hybrid SD-LIP against that of traditional LIP. It is worth noting that the simultaneous ablative effect of the catalyst surface to remove the carbon soot by the successive laser shots could prevent the catalytic deactivation leading to the sustained performance.

Dynamic changes in aroma compounds and precursor substances during rice cooking

Cooking is a key process in forming cooked rice flavor, and more data on aroma compounds should be needed during rice cooking. This paper tracked dynamic changes in aroma compounds, sugars, amino acids, and fatty acids during cooking. After soaking, the content of glucose, fructose, oleic acid, and linoleic acid increased. In the hydrothermal cooking stage, glucose, aspartic acid, glutamic acid, and alanine increased significantly (p < 0.05), while fructose, oleic acid, and linoleic acid first increased and then decreased. In raw rice and soaked rice, alkanes and alkenes were the main volatile compounds, and the content of hydrocarbon compounds decreased in the hydrothermal cooking stage, and many aldehydes, alcohols, ketones, and furan compounds were generated. A total of 28 aroma compounds were sniffed by GC-O-MS, and 13 aroma compounds with OAV >1 were screened out. These results showed that raw rice and soaked rice had similar aroma characteristics and aroma precursor substances that mainly accumulated in the SO10 or ST10 stage, and hydrothermal cooking was the key process of rice aroma formation.

Degree of Impact of Applying Environmental Cost Accounting on Tax Revenues from Oil Companies Operating in Iraq

Protecting the environment and its natural resources is an issue of great importance at the local and global levels. The phenomenon of environmental pollution resulting from the work of oil companies is one of the dangerous phenomena facing the environment in Iraq in general, and the environment of Kirkuk Governorate in particular, as the latter is considered one of the governorates rich in mineral resources, especially oil, as it contains six oil fields, and it contains the largest oil field in Iraq. Estimates indicate that it produces (40%) of the total Iraqi oil, so it suffers from a significant increase in the proportions of toxic and environmentally polluting gases resulting from the work of these companies in it. The work of oil companies from exploration, extraction and refining oil will naturally result in the emission of many gases that are highly toxic, dangerous and harmful to human health. The most important of these gases are carbon monoxide, sulfur dioxide, nitrogen dioxide, hydrocarbon compounds, hydrogen sulfide and other gases that pollute the environment, which has resulted in the spread and increase in the number of patients with respiratory diseases in a clear and increasing manner in the governorate. This increase in environmental costs falls on society as a whole, so it was necessary to identify and measure environmental costs from the society’s point of view and work to re-charge them to oil companies by applying the environmental tax.

Characterizing Wall Loss Effects of Intermediate-Volatility Hydrocarbons in a Smog Chamber with a Teflon Reactor

Intermediate-volatility organic compounds (IVOCs) serve as pivotal precursors to secondary organic aerosol (SOA). They are highly susceptible to substantial wall losses both in indoor environments and within smog chambers even with Teflon walls. Accurately characterizing the wall loss effects of IVOCs is thus essential for simulation studies aiming to replicate their atmospheric behaviors in smog chambers to ensure precise modeling of their physical and chemical processes, including SOA formation, yet a comprehensive understanding of the wall loss behavior of IVOCs remains elusive. In this study, we conducted a thorough characterization of wall losses for typical intermediate-volatility hydrocarbon compounds, including eight normal alkanes (n-alkanes) and eight polycyclic aromatic hydrocarbons (PAHs), using the smog chamber with a 30 m3 Teflon reactor. Changes in the concentrations of gaseous IVOCs with the chamber were observed under dark conditions, and the experimental data were fitted to the reversible gas–wall mass transfer theory to determine the key parameters such as the wall accommodation coefficient (αw) and the equivalent organic aerosol concentration (Cw) for different species. Our results reveal that Cw values for these hydrocarbon IVOCs range from 0.02 to 5.41 mg/m3, which increase with volatility for the PAHs but are relative stable for alkanes with an average of 3.82 ± 0.92 mg/m3. αw span from 1.24 × 10−7 to 1.01 × 10−6, with the values for n-alkanes initially showing an increase followed by a decrease as carbon numbers rise and volatility decreases. The average αw for n-alkanes and PAHs are 3.34 × 10−7 and 6.53 × 10−7, respectively. Our study shows that IVOCs exhibit different loss rates onto clean chamber walls under dry and dark conditions, with increasing rate as the volatility decreases. This study demonstrates how parameters can be acquired to address wall losses when conducting smog chamber simulation on atmospheric processes of IVOCs.

Development of Multiple Representation Learning Videos on Hydrocarbon Nomenclature

This research focuses on the development of learning media based on multiple representations in organic chemistry courses. Multiple representation-based learning media has the potential to improve students understanding of the concepts of chemical materials that are often considered difficult. However, the lack of learning media used by lecturers to discuss the three aspects of representation is a problem that needs to be addressed. This research aims to produce a nomenclature of hydrocarbon compounds learning video based on multiple representations and to find the eligibility and response for the developed learning video. The research methods are research and development using the 4d development model. The instruments used were the eligibility sheet and response questionnaire using a Likert scale. The eligibility for learning video is included as very feasible, with an average eligibility percentage of 95,03%. The eligibility of learning video was viewed in three aspects, namely, the lesson aspect (94.67%), the language aspect (95.56%), and the media aspect (94.87%). The responses given by students were included as a good category, as shown by the percentage of response results on the small-scale trial of 83,79% and large-scale trial of 83,31%. Based on the outcome of eligibility assessment and field trials, the nomenclature of hydrocarbon compounds learning video based on multiple representations is very feasible for learning media in the organic chemistry of monofunctional compounds course.

Transcriptome responses to benzo[a]pyrene in liver slices of sub-arctic fish species

Due to the expanding oil-related activities, the arctic and sub-arctic marine environments are increasingly vulnerable to oil-related pollution such as accidental oil spills. These cold-water ecosystems harbor many fish species that are both ecologically and economically important such as the pelagic polar cod (Boreogadus saida), capelin (Mallotus villosus), and benthic long rough dab (Hippoglossoides platessoides). The latter two are much less studied and it is crucial to characterize their responses to oil-related contaminants and develop molecular biomarkers and genomic resources for future monitoring. In this study, liver slice preparation and culture methods were used to characterize the transcriptome responses (using RNA-seq) in capelin and long rough dab to exposures of the polycyclic aromatic hydrocarbon (PAH) compound benzo[a]pyrene (BaP). The liver slice culture and exposure experiments were performed onboard a research vessel in the Barents Sea. Strong up-regulation of genes involved in biotransformation, particularly the aryl hydrocarbon receptor signaling pathway was observed in both species. A comparison of the number of differentially expressed genes (DEGs) with previously published polar cod exposures indicates that the latter responded more strongly (higher number of genes), suggesting higher uptake and bioconcentration of BaP in the fatty liver tissue, although other factors such as differences in clearance rate could potentially affect the responses. This study provides new genomic resources and gene expression biomarkers in capelin and long rough dab, enhancing our understanding of their response mechanism to oil-related contaminants.

Evaluation of the phytotoxicity and accumulation potential of nitro-polycyclic aromatic hydrocarbon, 3-nitrofluoranthene, on water status, photosystem II efficiency, antioxidant activity and ROS accumulation in Salvinia natans

Organic pollutants, which have become one of the most striking problems of today, raise concerns about the spread of polyaromatic hydrocarbon (PAH) compounds into ecosystems and their toxic effects on living organisms. The purpose of this study was to determine how harmful 3-nitrofluoranthene (3-NF) exposure was to Salvinia natans, a freshwater macrophyte. Furthermore, it clarifies how this aquatic plant, which is frequently used in phytoremediation of water contaminants and wastewater treatments, interacts with PAHs and contributes to the development of bioremediation methods. In S. natans exposed to stress (10 μM (3-NF10), 25 μM (3-NF25), 50 μM (3-NF50), 100 μM (3-NF100), 250 μM (3-NF250), 500 μM (3-NF500), 1000 μM (3-NF1000) 3-nitrofluoranthene), 3-NF accumulation, oxidative stress indicators, photosynthetic efficiency, and antioxidant system activity alterations were investigated for this objective. The findings demonstrated that S. natans could effectively accumulate 3-NF, and at a concentration of 1000 μM, the 3-NF content in the leaves reached approximately 1112 mg/kg. While its adverse effects on growth (RGR) and photosynthesis (Fv/Fm) remained mild up to a concentration of 250 μM, the severity of the inhibitions increased at higher concentrations. On the other hand, exposure to 3-NF triggered the antioxidant system in S. natans plants and resulted in an increase of 60 %, 80 %, 47 % and 27 % in superoxide dismutase (SOD) activity in 3-NF10–25–50-100 groups, respectively. Conversely, in comparison to control plants, higher concentrations of 3-NF treatments resulted in insufficient antioxidant activity, increased lipid peroxidation (TBARS concentration), and hydrogen peroxide (H2O2). In conclusion, S. natans plants tolerated 3-NF accumulation up to 250 μM concentration despite limitations in growth suppression and photosynthetic capacity, proving that S. natans has the potential to be used in phytoextraction studies of 3-NF-polluted waters.

Kairomonal Effect of Hexane Extracts of Corcyra cephalonica and Spodoptera frugiperda on the Parasitizing Activity of Trichogramma pretiosum.

Egg parasitoids, particularly Trichogrammatidae, play a crucial role in global biocontrol efforts. Their behavior is influenced by chemicals emitted by their hosts, such as kairomones. Among them, Trichogramma pretiosum(Riley)(Hym.; Trichogrammatidae)shows promise as a biocontrol agent on destructive Fall Armyworm (FAW), Spodoptera frugiperda(J.E. Smith) (Lep.; Noctuidae). Given the invasiveness and widespread impact of FAW, early-stage prevention in the field is imperative. This study aimed to assess the potential of host insects viz.,Corcyra cephalonica (Stainton) (Lep.; Pyralidae) and S. frugiperda kairomones in optimizing the performance of T. pretiosum while parasitizing S. frugiperda.The top two hexane extracts from each host insect were also sent to JNU, AIRF in New Delhi for detailed GC-MS analysis. A four-armed olfactometer was developed to track the movements of T. pretiosum and validated with olfactory cues. Laboratory bioassays revealed that extracts from C. cephalonica and S. frugiperda eggs and moths effectively enhanced the performance of T. pretiosum. Optimal concentrations were determined through Petri dish bioassays, with C1 (10%) concentration of C. cephalonica eggs extract showing the highest Parasitoid Activity Index (PAI), percent parasitization, and adult emergence. Meanwhile, C2 (1%) concentration of S. frugiperda female extract exhibited the highest parasitization percentage and adult emergence. Further assessments in a polyhouse setting demonstrated that treated egg cards positioned 1m from the release point achieved the highest mean percentage parasitization. Chemical composition analysis via GC-MS revealed that distinctive hydrocarbon and alcohol profiles in the extracts, suggesting their potential for manipulating parasitoid activity in biocontrol efforts. In the S. frugiperda female extract, 12 hydrocarbons and 3 alcohol groups were identified, with tetracontane as the predominant hydrocarbon compound followed by octane, heneicosane, and others. Meanwhile, the C. cephalonicaegg extract displayed 9 hydrocarbons and 1 alcohol group, with dodecane leading in area percentage among the hydrocarbons followed by decane, nonane and others. The outputs of current study highlighted that T. pretiosum's utilization of kairomones from C. cephalonica and S. frugiperda, enhancing its search behavior for host eggs. The identification and synthesis of these kairomonal compounds have the potential to revolutionize pest management, emphasizing the role of kairomones in empowering natural predators and parasitoids for sustainable agriculture.

Depth dimension in seepage detection: Insights for exploration and geological gas storage surveillance

The search for surface hydrocarbon seeps has historically served as a fundamental tool in the early stages of oil and gas exploration. However, as easily detectable surface hydrocarbon seeps become increasingly scarce, advancement in analytical capabilities have shifted the focus towards detecting ultra-trace levels of hydrocarbons, commonly referred to as microseepages. While it is critical to understand the distribution of hydrocarbon microseepage for assessing petroleum systems and optimizing exploration efforts, the role of sampling depth in the detection of microseepage remains poorly understood. In this study, we investigated the influence of sampling depth on microseepage detection, using passive soil-gas sampling techniques at depths ranging from 0.5 to 10 m at sites with hydrocarbon-bearing reservoirs and dry wells. Organic geochemical analysis, including thermal desorption-gas chromatography-mass spectrometry (GC-MS), was employed to identify and quantify hydrocarbon and nonhydrocarbon compounds.The study result demonstrates that sampling at the Minimal Interference Zone (MIZ) depths of 5 m or greater significantly mitigates the risk of interference signals, thereby enabling the identification and quantification of hydrocarbon microseepages at trace and ultra-trace concentrations. At these depths, the attenuation of non-hydrocarbon compounds was observed, making the hydrocarbon signal markedly more distinguishable. Geochemical characterization of the samples revealed spatial and vertical heterogeneity in the distribution of hydrocarbon compounds, indicative of variations in the microseepage mechanisms potentially influenced by factors such as sedimentary basin settings and secondary alterations associated with the vadose zone. By utilizing passive soil-gas sampling techniques coupled with GC-MS, this study emphasizes the importance of sampling depth to improve the detection of reliable microseepage signal while reducing interference and background noise. The proposed technique not only refines existing methodologies for petroleum system assessments but also paves the way for broader geological applications. Specifically, the approach offers critical insights for the development of high-resolution geochemical surveys adaptable for surface background profiling in CO2 sequestration projects to monitor for storage efficiency and seal integrity.

Synthesis of benzoic acid from catalytic co-pyrolysis of waste wind turbine blades and biomass and their kinetic analysis

This work aims to study the catalytic co-pyrolysis of waste wind turbine blades (WTB: consists of fiberglass/unsaturated polyester resin) and woody biomass (WB) over ZSM-5 and Y-type zeolite catalysts for the production of benzoic acid. The experiments were performed on an equal combination of WTB and WB (WTB/WB) and a fixed amount of catalyst (50 wt%) using a thermogravimetric (TG) analyser at 10, 20 and 30 °C/min. The evolved products from the catalytic co-pyrolysis process were recognized using TG-FTIR and GC/MS. The kinetic and thermodynamic characteristics of catalytic co-pyrolysis was studied using various linear and nonlinear approaches. Also, the decomposition curves were predicted mathematically using an artificial neural network algorithm. The results revealed that the mixture was decomposed in the presence of both catalysts in the form of dual decomposition peaks at 361–374 °C and 428–443 °C, respectively. Based on TG-FTIR results, the CO stretching and carbon dioxide clusters were their main functional groups. While the GC-MS analysis revealed that the released vapours were completely free of toxic styrene (the main compound of resin) and the catalytic co-pyrolysis treatment succeeded in converting it into highly abundant benzoic acid, especially at 10 °C/ min, with an estimated 71.4 % (ZSM-5) and 64 % (Y-type). Whereas the activation energy was estimated at 262–295 kJ/mol (ZSM-5) and 319–357 kJ/mol (Y-type) with almost similar reaction complexity when compared to the case of absence of catalysts. Finally, the developed ANN algorithm showed high efficiency in predicting TG decomposition zones for both WTB/WB mixtures over zeolite catalysts with R2 more than 0.99. These results demonstrate that WB and zeolite catalysts can be used for upgrading the pyrolysis oil of WTB and eliminate its toxic styrene and convert it into benzoic acid and other aromatic hydrocarbons compounds (such as benzene, alanine, and 2-Propanamine).

Pollutant Emissions and Oxidative Potentials of Particles from the Indoor Burning of Biomass Pellets.

Residential solid fuel combustion significantly impacts air quality and human health. Pelletized biomass fuels are promoted as a cleaner alternative, particularly for those who cannot afford the high costs of gas/electricity, but their emission characteristics and potential effects remain poorly understood. The present laboratory-based study evaluated pollution emissions from pelletized biomass burning, including CH4 (methane), NMHC (nonmethane hydrocarbon compounds), CO, SO2, NOx, PM2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm), OC (organic carbon), EC (element carbon), PAHs (polycyclic aromatic hydrocarbons), EPFRs (environmentally persistent free radicals), and OP (oxidative potential) of PM2.5, and compared with those from raw biomass burning. For most targets, except for SO2 and NOx, the mass-based emission factors for pelletized biomass were 62-96% lower than those for raw biomass. SO2 and NOx levels were negatively correlated with other air pollutants (p < 0.05). Based on real-world daily consumption data, this study estimated that households using pelletized biomass could achieve significant reductions (51-95%) in emissions of CH4, NMHC, CO, PM2.5, OC, EC, PAHs, and EPFRs compared to those using raw biomass, while the differences in emissions of NOx and SO2 were statistically insignificant. The reduction rate of benzo(a)pyrene-equivalent emissions was only 16%, much lower than the reduction in the total PAH mass (78%). This is primarily attributed to the more PAHs with high toxic potentials, such as dibenz(a,h)anthracene, in the pelletized biomass emissions. Consequently, impacts on human health associated with PAHs might be overestimated if only the mass of total PAHs was counted. The OP of particles from the pellet burning was also significantly lower than that from raw biomass by 96%. The results suggested that pelletized biomass could be a transitional substitution option that can significantly improve air quality and mitigate human exposure.

Theoretical and experimental constraints on hydrogen isotope equilibrium in C1-C5 alkanes

Stable isotope ratios of C1–C5 alkanes, the major constituents of subsurface gaseous hydrocarbons, can provide valuable insights on their origins, transport, and fates. Equilibrium isotope effects are fundamental to interpreting stable isotope signatures, as recognition of them in natural materials indicates reversible processes and constrains the temperatures of equilibrated systems. Hydrogen isotope equilibrium of C1–C5 alkanes is of particular interest because evidence shows that alkyl H can undergo isotopic exchange with coexisting compounds under subsurface conditions. We present the results of a combined experimental and theoretical effort to determine equilibrium hydrogen isotope distributions in mixtures of these hydrocarbon compounds. We created two mixtures: one with C1, C2 and C3 (where C1 indicates methane, C2 ethane, etc., hereinafter called ‘C1–C3 mixture’) and another one with C2, C3, iC4, nC4, iC5 and nC5 (hereinafter called ‘C2–C5 mixture’); in both cases, the mixtures were created to start out of hydrogen isotope equilibrium. We tested the performance of several metal catalysts as aids to H isotopic exchange by exposing these mixtures to different metal catalysts at 100 or 200 °C and analyzing the compound-specific hydrogen isotope ratios of the product gases. The C1–C3 mixture exchanged hydrogen isotopes among the starting gas components rapidly in the presence of Ru/Al2O3 at 200 °C. The isotope ratios reach a steady-state (presumably equilibrium) after 72 h of heating (up to 120 h). The hydrogen isotopic ratios of alkanes in the C2–C5 mixture shifted significantly in the presence of Rh/Al2O3 at 100 °C and C3-C5 compounds approached steady state after 70 h, whereas C2 had not yet reached a steady state D/H ratio after 216 h of heating. We evaluated the reaction progress of isotope exchange for each compound as a function of time with a reaction-network model informed by constraints on chemical kinetics. The model indicates that C3, iC4, nC4, iC5 and nC5 in the C2-C5 mixture reached internal isotope equilibrium after 70 h, hence we used their values to calculate experimental equilibrium results. We also calculated equilibrium isotope fractionations with the Bigeleisen-Mayer theorem using vibrational frequencies computed from the density functional theory (B3LYP/aug-cc-pVTZ). We included torsional conformers and explicit H positions in the calculations. We found that the experimental results from both the 200 ˚C C1–C3 experiment and 100 ˚C C2–C5 experiment are consistent with theoretical equilibrium results within experimental uncertainty. Additionally, our reaction-network model for catalyzed hydrogen isotope exchange between alkanes succeeded in fitting our experimental results. This modeling framework can be adjusted to simulate exchange in natural settings for constraining temperature histories and sources of natural gases.