Concentrations Of Hydrocarbons Research Articles

Assessment of the contamination by carbonaceous anthropogenic particulates and polycyclic aromatic hydrocarbons (PAHs) concentration in recreational areas of an estuary heavily industrialized in Northern Spain

The commercial management of coal and its by-products has the potential to negatively impact natural coastal environments. The coal conversion processes and coke production are sources of polycyclic aromatic hydrocarbons (PAHs) emissions that also contribute to the pollution of those aquatic environments. This research assesses the contamination by carbonaceous anthropogenic particles and by polycyclic aromatic hydrocarbons of some recreational sites (Arañón, Peña del Caballo and San Balandrán area) located in the Avilés' estuary, an area in Northern Spain that has been heavily industrialized since the 1950s. The results obtained indicate a low concentration of solid organic anthropogenic particles in the intertidal sediments of the recreational sites in the estuary, probably due to the protective measures set in place at the facilities managing bulk coal and coke, which prevents the dispersion of coal dust (and other materials) as well as the eventual failure into the estuary. The characteristics of 16 priority pollutants PAHs analyzed in two recreational sites of the estuary (San Balandrán area), their distribution by aromatic ring number together with their diagnostic ratios demonstrate a pyrogenic nature with a main source from processes of coal and coke conversion (including combustion) in the facilities around the estuary. Some contribution of PAHs derived from petroleum cannot be ruled out. This contamination by PAHS is constant and sustained over time. The majority of the considered PAHs are well above the Spanish Generic Reference Level, (GRL) established for “protection of ecosystems with aquatic organisms”, and only a few of them are notably above the corresponding Spanish GRL established for “other uses of land”, which should include lands for recreational activities. The analysis of the potential toxicity risk of PAHs for human health and the organisms of the aquatic ecosystem suggests a relatively low toxicity risk to very high toxicity risk in the San Balandrán environment according to the concentration and distribution trend of PAHs identified in this area. This trend is dependent on the coastal dynamics and the protection level of the site, which also affect the distribution of the anthropogenic carbonaceous particulates in the same way.

Concentration and health risk valuation of polycyclic aromatic hydrocarbons in Tilapia zilli in selected wetlands

Globally, food safety is growing, and the residues of PAHs (polycyclic aromatic hydrocarbons) in fish species above the standard threshold could elicit serious public and community health concerns. This study investigated the PAHs contamination concentrations of <i>Tilapia zilli</i> in the wetlands of the Niger Delta. The study was conducted from March to August 2023, and fish samples were collected within these periods from 5 wetlands. The results obtained were as follows: pyrene; 2.46±0.11 µg/kg, chrysene; 2.54±0.12 µg/kg, BaP; 2.52±0.11 µg/kg, BaA; 2.54±0.13 µg/kg and BbF; 2.54±0.13 µg/kg. The mean results of characterising the PAHs in the fish were insignificant at <i>p>0.05</i>. The results of the health risk evaluation showed that Beneze (a) pyrene had the highest value (12.33 µg/kg), followed by Benzo (a) anthracene and Benzo (b) fluoranthene (1.51 and 1.20) of the toxicity equivalent factors. Meanwhile, the sum across the station was significantly higher than the standard limits. The CDI (chronic daily intake) results obtained in this study for each PAH (polycyclic aromatic hydrocarbon) congener were considerably high and fluctuated across the stations. However, the results for the ILCR (incremental life cancer risk) showed that the values were higher (1 × 10<sup>−2</sup>) than the threshold set for this study (1 × 10<sup>−6</sup> to 1 × 10<sup>−4</sup>). The fish were thus contaminated above the acceptable limit; therefore, they are not fit for human consumption or for compounding animal feed.

Chemical exposure from the Hebei spirit oil spill accident and its long-term effects on mental health

While evidence indicates that exposure to oil spill incidents can affect mental health, it is unclear whether the mental health effects result from the incident itself or from exposure to associated chemicals. Oil contains chemicals that can impact mental health and these chemicals may have long-term effects due to their persistence in the environment. To address the gap in current knowledge, we conducted cross-sectional and prospective analyses of data from adults who participated in the Health Effects of the Hebei Spirit Oil Spill study. To assess chemical exposure from oil spills, we used indirect exposure indicators such as distance from the contaminated oil band to residences and duration of clean-up work, along with direct exposure indicators such as urine metabolite concentrations of volatile organic compounds and polycyclic aromatic hydrocarbons. Mental health assessments covered posttraumatic stress disorder (PTSD), depression, state anxiety, and trait anxiety. In the cross-sectional analyses, all four mental health issues were found to be associated with proximity to the oil band (p-value<0.05) and showed a positive association with clean-up work duration (p-value<0.05). Cox regression analysis revealed that higher urinary t, t-muconic acid levels were associated with an increased risk of depression (Hazard Ratio [HR] = 1.55, 95 % Confidence Interval [CI] = 1.05–2.28), and elevated 1-hydroxypyrene levels increased the risk of PTSD (HR = 1.60, 95 % CI = 1.03–2.48). Additionally, higher urinary 2-naphthol levels were associated with increased state anxiety (HR = 1.39, 95 % CI = 1.00–1.93) and trait anxiety (HR = 1.64, 95 % CI = 1.15–2.32). These associations persisted even after controlling for distance and duration variables related to psychosocial exposure. Our findings suggest that environmental disaster response plans should prioritize minimizing chemical exposure while also considering the duration and nature of the mental health impacts.

Quantitative expression of LNAPL pollutant concentrations in capillary zone by coupling multiple environmental factors based on random forest algorithm

The capillary zone plays a crucial role in migration and transformation of pollutants. Light nonaqueous liquids (LNAPLs) have become the main organic pollutant in soil and groundwater environments. However, few studies have focused on the concentration distribution characteristics and quantitative expression of LNAPL pollutants within capillary zone. In this study, we conducted a sandbox-migration experiment using diesel oil as a typical LNAPL pollutant, with the capillary zone of silty sand as the research object. The variation characteristics of LNAPL pollutants (total petroleum hydrocarbon) concentration and environmental factors (moisture content, electrical conductivity, pH, and oxidationreduction potential) were essentially consistent at different locations with the same height. These characteristics differed within range of 10.0–50.0 cm and above 60.0 cm from groundwater. A model for quantitative expression of concentrations was constructed by coupling multiple environmental factors of 968 sets-7744 data via random forest algorithm. The goodness of fit (R2) for both training and test sets was greater than 0.90, and the mean absolute percentage error (MAPE) was less than 16.00 %. The absolute values of relative errors in predicting concentrations at characteristic points were less than 15.00 %. The constructed model can accurately and quantitatively express and predict concentrations in capillary zone.

Physicochemical and Fungal Analysis of a Hydrocarbon-Polluted Soil at Amadi-Ama Creek of Bonny River Port Harcourt, Rivers State, Nigeria

Numerous hydrocarbon-utilizing fungal species have been implicated with the ability to utilize/degrade hydrocarbon as carbon source, which indicate their potential for environmental cleanup in hydrocarbon-contaminated sites. In this study, five (5) indigenous fungal species were isolated from a petroleum-hydrocarbon polluted soil at Amadi-ama Creek, Bonny river shoreline, Port Harcourt, Rivers State. These fungal species may have high potential to biodegrade petroleum hydrocarbon pollutants. Samples were collected randomly from the hydrocarbon impacted soil at Amadi-ama Creek, Bonny river shoreline. Sabouraud’s Dextrose Agar (SDA) and Czapek Agar were used as growth media. Samples were examined to assess the physical and chemical characteristics such as conductivity, pH, temperature, nitrate, iron, copper, zinc, chromium, phosphate, sulphate, total hydrocarbon content, total petroleum hydrocarbon, and polycyclic aromatic hydrocarbon. These parameters are known to influence the occurrence, diversity and distribution of microorganisms in an ecological niche. Soil pH showed to be acidic (6.21), result also showed that Total hydrocarbon content, Total petroleum hydrocarbon and Polycyclic aromatic hydrocarbon values were at 306.55mg/kg, 112.134mg/kg, 44.227mg/kg respectively establishing the incidence of hydrocarbon pollution. Electrical conductivity and Temperature were at 1250 Us/cm, and 29.580C respectively while Nitrate, Phosphate, Sulphate, Iron, Copper, Zinc, and Chromium values were at 1.228mg/kg, 0.751mg/kg, 20.214mg/kg, 18.431mg/kg, 0.113mg/kg, 0.121mg/kg, and 0.042mg/kg respectively. Monitoring of the soil quality established the incidence of hydrocarbon pollution as well the incidence of anthropogenic influence on the soil putting into cognizance human activities at the shoreline. Morphological identification of obtained fungal species led to their assignment into four (4) genera and five (5) species; Aspergillus niger (28%), Aspergillus flavus (22%), Cladosporium herbarum (20%), Penicillium notatum (17%), Fusarium spp (11%). The predominance of Aspergillus isolates (28% and 22%) in this study could be a pointer to their potential to utilize hydrocarbon as their sole source of nutrient. The isolation of these indigenous fungal species could serve as a baseline study on which further analysis such as hydrocarbon degradation screening test could determine their individual hydrocarbon degradation potentials and subsequent consideration as hydrocarbon degrading microbes in subsequent bioremediation study.

Metagenomic and isotopic insights into carbon fixation by autotrophic microorganisms in a petroleum hydrocarbon impacted red clay aquifer

Autotrophic microorganisms, the pivotal carbon fixers, exhibit a broad distribution across diverse environments, playing critical roles in the process of carbon sequestration. However, insights into their distribution characteristics in aquifers, particularly in those petroleum-hydrocarbon-contaminated (PHC) aquifers that were known for rich in heterotrophs, have been limited. In the study, groundwater samples were collected from red clay aquifers in the storage tank leakage area of a PHC site, a prevalent aquifer type in southern China and other regions. Metagenomics combined with hydrochemical and inorganic carbon isotope analyses were employed to elucidate the presence of microbial carbon fixation and its driving forces. Results showed that there were hundreds of autotrophic microorganisms participating in distinct carbon fixation processes in the red clay PHC aquifers. Reductive tricarboxylic acid (rTCA) and dicarboxylate/4-hydroxybutyrate (DC/4HB), as well as 3-hydroxypropionate (3HP or/and 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB)) were the predominant carbon fixation pathways. The abundances of carbon fixation genes and autotrophic microorganisms were significantly and positively correlated with hydrocarbon concentrations and δ13C of dissolved inorganic carbon (δ13C-DIC) values. This finding indicated that the petroleum hydrocarbon significantly promoted the proliferation of carbon fixation microorganisms, leading to a substantial uptake of inorganic carbon. Therefore, we deduce that this process holds considerable potential for carbon sequestration in PHC-contaminated aquifers.

Study on pyrolysis characteristics of Gonghe oil shale using Py-GC/MS under different atmospheres

ABSTRACT Taking Gonghe oil shale as raw material, the rapid pyrolysis experiment was carried out using the Py-GC/MS device under different atmospheres. The effects of different pyrolysis atmospheres on the rapid pyrolysis products of Gonghe oil shale were studied. The results show that the H2 atmosphere can not only increase the content of saturated hydrocarbons and reduce the content of unsaturated hydrocarbons but also reduce the content of oxygen-containing heterocyclic compounds. This may be because more H free radicals under the H2 atmosphere are produced to react with the free radical fragments formed by kerogen decomposition. The coupling between H free radicals and free radical fragments can prevent the polymerization among macromolecular free radicals and inhibit the generation of heavy byproducts, which can promote the kerogen pyrolysis and increase the release of volatile matter. In addition, the pyrolysis atmosphere is conducive to the deoxygenation of oxygen-containing heterocyclic compounds to a certain extent.

Toxicity of the oil spilled on the Brazilian coast at different degrees of natural weathering to early life stages of the zebrafish Danio rerio

Toxicity of water accommodated fractions (WAF) from the oil spilled on the Brazilian coast at different stages of weathering were investigated using Danio rerio. Weathering stages included emulsified oil that reached the coast (OM) and oil collected 50 days later deposited on beach sand (OS) or adhered to shore rocks (OR). Parent and alkylated naphthalenes decreased whereas phenanthrenes increased from less weathered WAF-OM to more weathered WAF-OS and WAF-OR. More weathered WAF-OS and WAF-OR were more potent inducers of zebrafish developmental delay, suggesting that parent and alkylated phenanthrenes are involved. However, less weathered WAF-OM was a more potent inducer of failure in swim-bladder inflation than more weathered WAF-OS and WAF-OR, suggesting that parent and alkylated naphthalenes are involved. Decreases in heart rates and increased heart and skeletal deformities were observed in exposed larvae. Lowest observed effect concentrations for different developmental toxicity endpoints are within environmentally relevant polycyclic aromatic hydrocarbon concentrations.

Changes of structural characteristics, functional properties and volatile compounds of Tenebrio molitor larvae protein after sustainable defatting process: Influence of the different volume ratios of n-hexane to ethanol

This work aimed to study the effect of defatting via the mixture of n-hexane and ethanol under different volume ratio on the changes of structural characteristics, functional properties and volatile compounds of Tenebrio molitor larvae protein (TMLP). The results showed that 1:0.6 vol ratio of n-hexane to ethanol rendered the highest defatting rate (P < 0.05), as well as led to the highest EAA/AA contents, sulfhydryl contents, surface hydrophobicity, solubility, water/oil holding capacities and emulsifying properties of TMLP (P < 0.05). However, higher volume ratio of n-hexane to ethanol led to negative impacts on functionalities of TMLP. Moreover, the contents of aldehydes and hydrocarbons which rendered off-flavour to TMLP significantly decreased with the increasing volume ratio of n-hexane to ethanol (P < 0.05), while the contents of pleasure flavour (hydrocarbons and ester compounds) were obviously enhanced. This study provides an eco-friendly defatting method on the processing of TMLP with superior quality attributes.

An integrated convolutional neural network prediction framework for in situ shale oil content based on conventional logging data

The quantification of total organic carbon (TOC) and the free hydrocarbon content (S 1 ) is crucial for evaluating the shale oil generation and bearing properties of source rocks. This study aimed to enhance the accuracy of TOC and S 1 quantification in shale oil evaluations. The scope encompassed the development of a novel deep learning framework to overcome the limitations of traditional physical and machine learning or deep learning methods. This paper proposes an integrated swarm optimization algorithm–convolutional neural network/machine learning framework. This framework uses a swarm optimization algorithm for the hyperparameter optimization of a convolutional neural network or machine learning framework, utilizing experimental data from core samples preserved in liquid nitrogen alongside well logging data. The application of the proposed framework to the H11 well in the Subei Basin, China, using 110 core samples, demonstrated a superior performance. The results validate the framework's effectiveness in predicting the TOC and S 1 contents at various depths. The proposed framework stands out for its convenient methodology, wide application range and high precision in prediction. These attributes contribute significantly to the field of petroleum engineering and development, offering a novel approach that promises to enhance both the efficiency and accuracy of well logging evaluation.

Analysis of the microbial community structure and characteristic flavor of traditional fermented bean paste.

Bean paste is a traditional Chinese fermented condiment, which is loved by consumers for its pleasant flavor and nutritional properties. However, the microbial communities and related flavor compounds in bean paste remain unclear. We studied the correlation between the core functional microorganisms and flavor compounds in bean paste samples at different fermentation stages. Bacterial and fungal communities changed significantly during fermentation. The results indicated that the dominant bacterial genera were Staphylococcus, Lactococcus, and Bacillus. The dominant fungi were Aspergillus and Lichtheimia. During the early and late stages of bean paste fermentation, alcohols, hydrocarbons, esters, and phenols were the main flavor compounds detected. The types and proportions of alcohols and esters in the bean pastes fermented for different durations were similar, whereas the relative contents of phenols and hydrocarbons were higher in the later stages of fermentation. Correlation analysis revealed that core functional microorganisms played a key role in the fermentation process, and the potential correlation between bacterial genera and flavors was stronger than that of fungal genera. Staphylococcus abundance was significantly correlated with the flavor levels of ethyl oleate, ç-pinene, diallyl disulfide, á-myrcene, D-limonene, and tetradecanoic acid, ethyl ester. The abundance of Aspergillus and Lichtheimia was significantly correlated with the flavor levels of á-myrcene, ç-pinene, and DL-3-phenyllactic acid. This study explored the relationship between microorganisms and flavor compounds in bean paste to deepen our understanding of the mechanism of flavor formation for bean paste.

International airport emissions and their impact on local air quality: chemical speciation of ambient aerosols at Madrid–Barajas Airport during the AVIATOR campaign

Abstract. Madrid–Barajas Airport (MAD) is the fourth-busiest airport in Europe. The aerosol chemical composition and the concentrations of other key pollutants were measured at the airport perimeter during October 2021 to assess the impact of airport emissions on local air quality. A high-fidelity ambient instrumentation system was deployed at Madrid–Barajas Airport to measure the following: concentrations of organic aerosols (with their composition), black carbon (eBC), carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NOx), sulfur dioxide (SO2), particulate matter (PM2.5, PM10), total hydrocarbon (THC), and total particle number. The average concentrations of eBC, NOx, SO2, PM2.5, PM10, CO, and THC at the airport for the entire campaign were 1.07 µg m−3, 22.7 µg m−3, 4.10 µg m−3, 9.35 µg m−3, 16.43 µg m−3, 0.23 mg m−3, and 2.30 mg m−3, respectively. The source apportionment analysis of the non-refractory organic aerosol (OA) using positive matrix factorisation (PMF) allowed us to discriminate between different sources of pollution, namely less oxidised oxygenated organic aerosol (LO-OOA), alkane organic aerosol (AlkOA), and more oxidised oxygenated organic aerosol (MO-OOA). The results showed that LO-OOA and MO-OOA account for more than 80 % of the total organic particle mass measured near the runway. Trace gases correlate better with the AlkOA factor than LO-OOA and MO-OOA, indicating that AlkOA is mainly related to primary combustion emissions. Bivariate polar plots were used for pollutant source identification. Significantly higher concentrations of the obtained factors were observed at low wind speeds (&lt;3 m s−1) from the southwest, where two of the runways and all terminals are located. Higher SO2/NOx and CO/eBC ratios were observed when the winds originated from the northeast, where the two northern runways are located. These elevated ratios are attributed to the aircraft activity being the major pollutant source in the northeast area.

Green transformation of oily sludge through geopolymer: Material properties and hydration mechanisms

Oily sludge (OS) is a kind of hazardous waste generated from the petrochemical industry. Currently, pyrolysis has been widely applied for OS disposal, while low-oil content (<5 wt%) OS still lacks novel technology to achieve efficient resource utilization and harmful substances immobilization. In this study, a kind of OS-based geopolymer was developed by OS and ground granulated blast furnace slag (GGBS). The results showed that in geopolymer with 30 wt% OS, the content of total petroleum hydrocarbons (TPHs) decreased by 82%, Zn achieved 100% stabilization, and the 28 d compressive strength could still reach 32.8 MPa. The appropriate oil content filled the pores and cracks in geopolymer matrix. The constructed model compounds further elucidated the hydration mechanisms of OS-geopolymer. The nucleation effect of crude oil and micro-aggregate effect of minerals jointly improved the polymerization degree of C-(A)-S-H gels. OS promoted the transformation of [SiO4]4− monomers into C-(A)-S-H unbranched middle groups and three-dimensional networks, thereby efficiently stabilizing harmful substances. Sustainability analysis showed that OS-based geopolymer had good environmental and economic benefits. Overall, this work provides theoretical guidance for the green transformation of OS in the construction field.

Optical investigation on lubricant combustion characteristics under the ammonia-methane premixed environment

The combustion process is an indispensable energy conversion step in modern industry and energy production. Especially in high-performance engines and energy conversion systems, understanding and controlling the combustion process is critical to improving efficiency and reducing environmental pollution. As a key component of mechanical systems, the combustion characteristics of lubricants at high temperatures and pressures have a direct impact on system performance and emissions. This study investigated the combustion characteristics of lubricant films in an ammonia-methane premixed environment using Planar Laser-Induced Fluorescence (PLIF) and Planar Laser-Induced Incandescence (PLII). It focused on the effects of varying ammonia concentrations on the emission of soot and polycyclic aromatic hydrocarbons (PAHs) in the constant volume combustion vessel. Experiments varied the ammonia-to-methane molar ratios, initial oil film thickness, and base oil type to study their influence on the lubricant combustion characteristics. Results indicated that ammonia significantly reduced soot formation by altering the dynamics of NH* and OH* and impacting PAH distribution. For the lubricating oil soot formation factors, the increase of the initial mean oil film thickness was more obvious for the promotion of soot formation, the increase of the unsaturated hydrocarbon content in the oil film also promoted the generation of carbon soot to a certain extent, and the initial flame energy ratio had the least influence on the promotion of soot formation. Overall, the study contributed to the understanding of the formation mechanism of soot caused by lubricating oil in zero-carbon and low-carbon blended atmospheres and provided a new insight into the interaction between nitrogen-containing zero-carbon fuels and large-carbon-number hydrocarbons, which is of great significance for controlling soot emissions from engines under zero-carbon fuel blending.

The ATP-binding cassette transporter subfamily G member 4 mediates cuticular hydrocarbon transport to regulate drought tolerance in Acyrthosiphon pisum

ABC transporters are a highly conserved membrane protein class that promote the transport of substances across membranes. Under drought conditions, insects primarily regulate the content of cuticular hydrocarbon (CHC) to retain water and prevent evaporative loss. Involvement of ABC transporter protein G (ABCG) subfamily genes in insect CHC transport has been relatively understudied. In this study, we demonstrated that ABCG4 gene in Acyrthosiphon pisum (ApABCG4) is involved in CHC transport and affects drought tolerance by regulating CHC accumulation. ApABCG4 is strongly expressed in the abdominal cuticle and embryonic stages of A. pisum. Effective silencing of ApABCG4 was achieved using RNAi, and the silencing duration was analyzed. ApABCG4 silencing resulted in a significant decrease in the total and component contents of the CHC and cuticular waxy coatings of A. pisum. Nevertheless, the internal hydrocarbon content remained unchanged. The lack of cuticular hydrocarbons significantly reduced the drought tolerance of A. pisum, shortening its survival time under drought stress. Drought stress caused significant upregulation of ApABCG4. Molecular docking showed that ApABCG4 has a high binding affinity for nine n-alkanes of CHC through electrostatic interactions. These results indicate that ApABCG4 is a novel RNAi target with key applications in aphid biological control.

Determination of Gas–Oil minimum miscibility pressure for impure CO2 through optimized machine learning models

Minimum miscibility pressure (MMP) is one of the most important parameters for designing CO2 enhanced oil recovery (EOR) and associated storage in depleted oil reservoirs. The injection gas stream often contains a certain concentration of impurities such as N2, H2S, and CH4 depending on the source of CO2. These impurities have different effects on CO2 MMP, but there is a lack of widely accepted approaches to account for these effects on MMP calculation. In this study, a series of activities were conducted to develop a machine learning (ML)-based methodology for determining MMP for CO2 with various impurities. A database containing 234 CO2 MMP test sets with around 5000 data points was built based on the reported experimental measurements in the public domain. The database was then subgrouped by three specific criteria: CO2 concentration in the injection gas, type of impurities in the injection gas, and heavier hydrocarbon content in the oil. This subgrouping was essential to capture the impact of different factors on CO2 MMP. An ensemble ML approach with seven ML models, including random forest, adaptive boosting, light gradient boosting machine, extreme gradient boosting (XGBoost), stacking, artificial neural network, and voting regressor, was employed to calculate MMP based on the subgrouped database. The hyperparameters of these ML models were optimized by the grid search technique to minimize the relative errors between calculated and measured MMP values. The performance of each algorithm was assessed using three regression metrics: average absolute relative error (AARE), R-squared score (R2), and root mean square error (RMSE). All of these metrics exhibited satisfactory values for the optimized ML models. The average values of R2, RMSE, and AARE were 0.962, 1.571, and 4.55%, respectively, for the three subgroups, indicating a high accuracy of MMP calculations using the optimized ML models. The XGBoost model emerged as the top performer across the three metrics, with an R2 of 0.979, an AARE of 2.835%, and an RMSE of 1.183 for a dataset with 190 cases. The overall high level of accuracy confirmed the reliability of these ML models in calculating MMP for CO2 with different impurities as well as the importance of optimization in the modeling process.

Pore Morphology and Oxidation Behaviour of Deep-Loaded Granular Coal at High Initial Temperatures

ABSTRACT As coal mining proceeds deeper, fragmented coal is subjected to high geostress and elevated thermal environments, causing changes in its micro-physical properties and spontaneous combustion (SC) risks. Deep mining operations entail significant risks of coal fires. In order to investigate the effects of high stress and high thermal environments on the microstructural and physicochemical damage of fragmented coal, and to elucidate the mechanisms influencing oxidation behavior, we conducted experiments including low-temperature nitrogen adsorption, synchronous thermal analysis, and in-situ diffuse reflectance spectroscopy. These experiments aimed to explore the pore morphology and oxidation characteristics of high initial temperature unloading granular coal (HITU-GC) unloading conditions. The results indicate that with increasing initial temperature, characteristic point temperatures initially rise and then decrease, while both the mass loss and heat release during the low-temperature oxidation stage decrease. After pressure-unloading composite treatment, the oxidation process accelerates with more intense reactions, resulting in an overall increase in heat release. The pore shapes of HITU-GC show no significant difference compared to the original coal, mainly comprising non-rigid aggregates of micropores, platy or layered matrix particles, including numerous slit-shaped pores. The coal surface also exhibits ink bottle-shaped pores and cone-shaped pores. Higher pre-oxidation temperatures correlate with higher specific surface areas. Higher stress levels from pressurized unloading correlate with lower specific surface areas. The specific surface area of sample O60-P16 is reduced by 0.879 m2/g compared to sample O60-P0. Pressurized unloading treatment disrupts mesoporous pores. Following thermal environment and pressure-unloading, the coal’s aromatic hydrocarbon content decreases, while the contents of hydroxyl, aliphatic hydrocarbons, and oxygen-containing functional groups (FG) all increase. Sample O60-P4 shows the highest content of active FG. While thermal environments enhance coal oxidation activity, pressure-unloading treatment increases the extent of coal surface fragmentation. The synergistic effect of both significantly increases the SC risk of coal. This study provides a theoretical basis for controlling thermal hazards associated with high-initial-temperature unloading fragmented coal in deep goaf areas.

Biodegradation of oily waste sludge using vermiremediation and composting process bioaugmentated with isolated hydrocarbon-degrading bacteria: Performance and ecotoxicity assessment

Degradation of petroleum hydrocarbons (PHs) contents of oily waste sludge (OWS) is necessary in order to prevent the related environmental pollution. The present study aimed to investigate the degradation of total petroleum hydrocarbons (TPHs) from OWS using bioaugmentated composting (BC) with hydrocarbon-degrading bacterial consortium (HDBC) as pre-treatment followed by vermicomposting (VC) by Eisenia fetida. After isolating two indigenous bacterial strains from OWS, the ability of their consortium in degradation of crude oil was tested in Bushnell-Haas medium (BHM). Then, biodegradation of OWS was measured in the VC alone, BC alone, simultaneous BC and VC (BCVC), and BC followed by VC (BCFVC) containing high levels (30 g/kg) of TPHs. Toxicity tests including the mortality of mature earthworms and the numbers of juveniles were conducted at the TPHs of 0–40 g/kg. The obtained results indicated that the HDBC removed 18–64 % of TPHs of crude oil (1–5 %) in BHM after 7 days of incubation. After a period of 12 weeks, the removal rates of TPHs in the VC, BC, BCVC, and BCFVC experiments were 23.7, 79.5, 85.2, and 91.8 %, respectively, verifying the efficacy of simultaneous application of HDBC and worms in bioremediation of OWS. The TPHs contents of OWS exhibited toxic effects on E. fetida at some concentrations and the median lethal concentration (LC50) of TPHs was computed to be 14.5 g/kg after 28 days. This study demonstrated the effectiveness of composting bioaugmentated with HDBC as a pre-treatment step followed by vermicomposting in bioremediation of OWS.

Two-stage hydrothermal liquefaction of Spirulina: Experimental observations, energy analysis and techno-economic assessment

The intensification of environmental pollution and significant consumption of fossil fuels has led to widespread attention on developing renewable resources. As a carbon-containing renewable energy source, Spirulina is characterized by its fast growth cycle and wide distribution. Currently, one of the research hotspots is the conversion of Spirulina into bio-oil through hydrothermal liquefaction. However, studies on the two-stage hydrothermal liquefaction of Spirulina predominantly concentrate on the product yield or composition. There is relatively little research on thermodynamic (energy) analysis and techno-economic assessment during the reaction process. The main bio-oil components from two-stage hydrothermal liquefaction of Spirulina are ketones and acids with 44.9 % and 34.1 %, respectively. Compared to no-catalysis, two-stage hydrothermal liquefaction of Spirulina over HZSM-5, alkili-modified HZSM-5, and Ni@alkali-modified HZSM-5 increase the relative content of hydrocarbons to 6.6 %, 32.9 % and 48.1 %, respectively. Energy analysis and techno-economic assessment are conducted with Aspen Plus simulation, revealing a exergy efficiency of 56.4 % for the catalytic two-stage hydrothermal liquefaction of Spirulina compared with 43.6 % over no-catalyst. The primary losses occur in the first stage of the reaction process (248.6 kW) and the cooling process (10.7 kW) for catalytic two-stage hydrothermal liquefaction of Spirulina. The hourly price of producing 1 kg bio-oil with a catalyst is $3.67, while without a catalyst, it is $4.54 kg−1; obtaining a unit of chemical exergy costs $0.14×10−3 kJ−1 through catalysis. Moreover, the fluctuations in the prices of sulfuric acid and catalysts are most sensitive to the cost price of bio-oil with or without catalysts in the two-stage hydrothermal liquefaction process, with the values being 10.06 % and 8.10 %. This study has important significance for efficient transformation and energy utilization of Spirulina.

Hydrogen Gas-Grilling in Meat: Impact on Odor Profile and Contents of Polycyclic Aromatic Hydrocarbons and Volatile Organic Compounds.

The effect of fuel (hydrogen vs. butane) on the formation of volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) was evaluated for grilled horse meat (very low-fat and low-fat) cooking vertically. Gas chromatography-mass spectrometry was used to analyze PAHs and VOCs. An electronic nose was used to evaluate the odor profile. Total high-molecular-weight PAHs ranged from 19.59 to 28.65 µg/kg with butane and from 1.83 to 1.61 µg/kg with hydrogen. Conversely, total low-molecular-weight PAHs went from 184.41 to 286.03 µg/kg with butane and from 36.88 to 41.63 µg/kg with hydrogen. Aldehydes and alkanes were the predominant family in a total of 59 VOCs. Hydrogen gas-grilling reduced significantly (p < 0.05) the generation of VOCs related to lipid oxidation. The odor profile was not modified significantly despite the change of PAHs and VOCs. The findings indicate that hydrogen is a viable alternative to butane for grilling horse meat. Hydrogen gas-grilling may be regarded as a safe cooking procedure of meat from a PAH contamination point and perhaps sustainable environmentally compared to a conventional technique. The present study provides the basis for the use of hydrogen gas in grilled meat.