Search Results (53)

The main advantage of using biomass for energy generation is the reduction in carbon dioxide emissions. For a fast reduction effect, it is important to use biomass characterised by an annual growth cycle. These may be fallen leaves. The fuel properties of the leaves can change during the growth period. These changes can result from both the natural growth process and environmental factors—particulate matter adsorption. The main objective was to determine changes in the characteristics of leaves and needles during the growth period (from May to October). Furthermore, to determine the effect of adsorbed particulate matter, the washing process was carried out. Studies were carried out for three tree species: Norway maple, horse chestnut and European larch. Proximate and ultimate analysis was performed and mercury content was determined. During the growth period, beneficial changes were observed: an increase in carbon content and a decrease in hydrogen and sulphur content. The unfavourable change was a significant increase in ash content, which caused a decrease in calorific value. The increase in ash content was caused by adsorbed particulate matter. They were mostly absorbed by the tissues of the needle and leaves and could not be removed by washing the surface. Full article

Solid fuels are still widely used in household heating in Europe and North America. Emissions from boilers are released in proximity to people. Therefore, there is a need to minimise the toxicity of emissions affecting human health to the greatest extent possible. This study compares the genotoxic potential of the emissions of four boilers of modern and old design (automatic, gasification, down-draft, over-fire) operating at reduced output to simulate the real-life combustion fed by various fossil and renewable solid fuels (hard coal, brown coal, brown coal briquettes, wood pellets, wet and dry spruce). Organic emissions were tested for genotoxic potential by analysing bulky DNA adducts and 8-oxo-dG adduct induction. There was no consistent genotoxic pattern among the fuels used within the boilers. Genotoxicity was strongly correlated with polycyclic aromatic hydrocarbon (PAH) content, and even stronger correlation was observed with particulate matter (PM). In all measured variables (PM, PAHs, genotoxicity), the technology of the boilers was a more important factor in determining the genotoxic potential than the fuels burned. The highest levels of both bulky and 8-oxo-dG DNA adducts were induced by organics originating from the over-fire boiler, while the automatic boiler exhibited genotoxic potential that was ~1000- and 100-fold lower, respectively. Full article

Hopanoids are a series of important lipid biomarkers in the bacterial cellular membranes that are found ubiquitously in different spatial and temporal environments. Squalene-hopane cyclase, a key and prerequisite molecular component of the hopanoid biosynthesis pathway, is encoded by the sqhC gene. To investigate the composition, niche, and distribution of microbial sqhC-containing communities, we analyzed hopanoid producer data and environmental parameters across different ecosystems on the basis of sequencing reads of peat samples from increasing gradient depths across peatland profile C in the Dajiuhu Peatland, as well as data collected from available published papers. The results indicated that the acidic Dajiuhu Peatland harbored mainly Acidobacteria (59.16%) among its sqhC-containing groups. The main composition of hopanoid producers in the peatland was different from that in other ecosystems, with Alphaproteobacteria found in soil (37.78%), cave (48.21%), hypersaline lagoon (34.04%), and marine (32.59%) ecosystems; Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria found in reef (100%), acid mine drainage (55.00%), and estuary, mangrove, and harbor (39.66%) ecosystems; and an unknown cluster found in freshwater (29.43%) and hot spring (89.58%) ecosystems. Compared with other phyla or sub-phyla, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria were the most widespread, occurring in eight ecosystems. Peatland was significantly separated from the other nine ecosystem modules in the occurrence network, and the marine ecosystem had the greatest impact on the eco-network of sqhC microbes. An RDA indicated that pH, DO, salinity, and TOC had significant impacts on sqhC-containing microbial communities across the different ecosystems. Our results will be helpful to understanding the diversity, composition, and distribution of the sqhC community and its response to multiple environmental factors across different ecosystems. Full article

Carbon isotope of the kerogen (δ¹³C_org), steranes/hopanes (S/H), and C₂₈/C₂₉ sterane ratios in the source rocks from the SARK section at the Early Cambrian Yurtus Formation in the Fortunian Stage in the Tarim Basin of Northwest China reveal a positive excursion that is associated with biological diversity. The enrichment of vanadium/(vanadium + nickel) (V/(V + Ni)) ratios (0.64~0.99, averaging 0.87) for the Yurtus Formation of the Fortunian Stage provide evidence for predominant anoxic bottom water conditions. A sharply decreased V/(V + Ni) ratio in the middle Yurtus Formation suggests enhanced oxygen content of the water column in this interval. However, the total organic carbon (TOC) values in the sedimentary rocks show a marked increase in the middle Yurtus Formation, which is due to the enhanced productivity suggested by a positive δ¹³C_org increase of ~2.0‰ and enhanced S/H and C₂₈/C₂₉ sterane ratios. We suggest that the enhanced oxygen content may have contributed to the biological diversity during the Fortunian Stage in the Tarim Basin. The δ¹³C_org excursion first reported here associated with biological diversity can be correlated with that in South China and possibly elsewhere in this interval. Full article

The carbon isotopic behavior of hopane compounds during thermal maturation remains ambiguous due to limitations in current detection techniques. In this study, a low-maturity lacustrine shale sample was pyrolyzed in a hydrous semi-open pyrolysis system. The hopane compounds from the artificially matured samples (R_o = 0.72–1.28%) have been separated and enriched for the test of their carbon isotopes (δ¹³C). The results show that thermal maturity can somewhat affect the carbon isotopes of monomeric hopane compounds, with a maximum difference value over 21‰. However, thermal maturity has different effects on the δ¹³C values for different monomeric hopane compounds. For example, the carbon isotopic values of 22S-homohopane at different thermal stages can vary up to 21‰, while only 3‰ for C₂₉βα. In addition, the carbon isotopes of different monomeric hopane compounds show distinct evolution trends. For C₂₉αβ and C₂₉ Ts, their carbon isotopes first become slightly heavier and then become lighter, reaching the lightest value at 350 °C. When the pyrolysis temperature continues to increase, the δ¹³C values become heavier and finally become lighter. However, the δ¹³C values of Ts, Tm, 22S-homohopane, and 22R-homohopane show a completely reversed trend. They initially become slightly lighter and then become heavier, reaching the maximum value at 350 °C. When the pyrolysis temperature continues to increase, the δ¹³C values become lighter and finally become heavier. Meanwhile, the carbon isotopes of C₂₉βα, C₃₀αβ, C₃₀βα, and non-hopane gammacerane almost remain constant at different thermal stages. When the carbon isotopes of hopane compounds are used in the studies of oil–source correlation, it is prudent to consider the effects of thermal maturity on these values. Full article

This study investigates the performance of DC corona discharge electrostatic precipitators (ESPs) for NO conversion to increase DeNO_x technologies’ efficiency for small-scale biomass combustion systems. Experiments were conducted using a 5 kW automatic wood pellet domestic heat source with combustion gas treated in a specially designed ESP operated in both positive and negative corona modes, resulting in a reduction in NO concentrations from 130 mg/m³ to 27/29 mg/m³ for positive/negative polarities (at 0 °C and 101.3 kPa). NO conversion efficiency was evaluated across a range of specific input energies (SIEs) from 0 to 50 J/L. The results demonstrate that DC corona ESPs can achieve up to 78% NO reduction, with positive corona demonstrating a greater energy efficiency, requiring a lower SIE (35 J/L) compared to the negative corona mode (48 J/L). A detailed analysis of reaction pathways revealed distinct conversion mechanisms between the two modes. In positive corona, dispersed active species distribution led to more uniform NO conversion, while negative corona exhibited concentrated reaction zones with about 20% higher ozone production. The reactions involving O and OH radicals were more important in positive corona, whereas ozone-mediated oxidation dominated in negative corona. The research results demonstrate that ESP technology with DC corona offers a promising, energy-efficient solution for NO_x control in small-scale combustion systems. Full article

Electrostatic precipitators (ESPs) have shown promise in reducing particulate matter (PM) emissions, but their potential for simultaneous NOx reduction in small-scale combustion systems remains underexplored. This study focuses on using non-thermal plasma generated in a corona discharge to reduce PM and NOx emissions from small-scale combustion. ESP was specifically designed for a commercially available 15 kW boiler with wood pellet combustion and used with both positive and negative discharge polarity to control emissions without any chemical additives. ESP performance was evaluated across a range of specific input energies (SIE) in terms of particle mass and number concentrations and NOx concentrations obtained by continuous gas analysis. ESP ensured the reduction in PM concentrations from 48 mg/m³ to the magnitude of PM content in the ambient air. The highest precipitation efficiency was observed for particles in the 20–200 nm range. Concurrently, NOx emissions were reduced by up to 78%, from 178 mg/m³ to 39 mg/m³. These results were achieved at specific input energies of 36 for positive and 48 J/L for negative corona, which is significantly lower than those reported for many existing separate PM and NOx control systems. This study demonstrates the potential of ESPs as a compact, energy-efficient solution for simultaneous PM and NOx removal in small-scale combustion systems, offering promising implications for improving air pollution control technologies for small-scale combustion systems. Full article

The Zonguldak coal basin is the area with the most important hard coal reserves in Turkey. This study focuses on coal samples extracted from three seams of the Kozlu Formation, specifically from the Kozlu underground mine, to assess the coals’ organic geochemical and petrographic properties. Analytical methods, including TOC-pyrolysis, biomarker analysis, and maceral distribution studies, were employed. Based on these analyses, the paleoenvironmental conditions and hydrocarbon generation potential of the coals were evaluated. The results reveal that the coals, characterized by high TOC, high HI, and low OI, contain type II–III kerogen. These findings, coupled with the high QI and low BI values, suggest the presence of oil–gas prone source rocks. Elevated Tmax (457–466 °C) and Rr (0.89%–1.17%) values indicate a maturity level ranging from mature to overmature stages. High GI and GWI values suggest a significant degree of gelification and wet conditions during formation. The high Pr/Ph (1–6.58), C₃₁R/C₃₀ hopane (<0.25), and low DBT/P (0.27–0.50) ratios show that the Acılık seam was formed in a lacustrine environment under anoxic–suboxic conditions, whereas the Büyük and Domuzcu seams were formed in a fluvial/deltaic environment under oxic conditions. The findings of this study suggest that the paleovegetation in coal-forming environments consisted of aquatic and herbaceous plants. Full article

Ferromanganese formations are widespread in the Earth’s aquatic environment. Of all the mechanisms of their formation, the biogenic one is the most debatable. Here, we studied the Fe-Mn crusts of hydrothermal fields near the underwater volcano Puy de Folles (rift valley of the Mid-Atlantic Ridge). The chemical and mineralogical composition (optical and electron microscopy with EDX, X-ray powder diffraction, X-ray fluorescence analysis, Raman and FTIR spectroscopy, gas chromatography—mass spectrometry (GC-MS)) and the magnetic properties (static and resonance methods, including at cryogenic temperatures) of the samples of Fe-Mn crusts were investigated. In the IR absorption spectra, based on hydrogen bond stretching vibrations, it was concluded that there were compounds with aliphatic (alkane) groups as well as compounds with double bonds (possibly with a benzene ring). The GC-MS analysis showed the presence of alkanes, alkenes, hopanes, and steranes. Magnetically, the material is highly coercive; the blocking temperatures are 3 and 13 K. The main carriers of magnetism are ultrafine particles and X-ray amorphous matter. The analysis of experimental data allows us to conclude that the studied ferromanganese crusts, namely in their ferruginous phase, were formed as a result of induced biomineralization with the participation of iron-oxidizing and iron-reducing bacteria. Full article

Although current EU regulations, such as EU Directive 2015/1189 on the eco-design of solid fuel boilers and Directive 2015/1188, in accordance with the Machinery Directive 2006/42/EC, require manufacturers to meet specific emission requirements for CE marking, the routine and regular onsite testing of household heating appliances is still not mandatory in many EU countries. This research endeavour addressed this gap by evaluating the effectiveness of the Bacharach method as a rapid and cost-effective tool for assessing flue gas quality, particularly in terms of particulate matter mass concentration. This study also compared the results of the Bacharach method with those obtained from two commercially available portable analysers. The research outcomes demonstrate that the Bacharach method, in combination with an innovative evaluation approach, offers a viable solution, enabling the swift and economical assessment of flue gas quality with the primary objective of determining the boiler class according to the limits specified by standard EN 303-5 under operating conditions. The modified Bacharach method for measuring TSP in solid fuel-fired boilers provides qualitatively similar results to the commercially used SM500 and STM225 instruments. The modified Bacharach methodology was primarily developed for comparison to the boiler class 3 limit (i.e., 125 and 150 mg/m³). The study revealed that the modified Bacharach method, when applied to biomass-based boilers, exhibited higher accuracies in the case of classification into classes 3 and 4, whereas fossil fuel-based boilers demonstrated higher accuracy in the case of class 5 limits. Full article

Surface sediment samples from Al-Qahma lagoon in the southern part and Al-Wajh lagoon in the northern part of the Red Sea coast of Saudi Arabia were collected by a Van Veen grab sampler to determine the characteristics, distribution, and sources of aliphatic and cyclic hydrocarbons. The total extractable organic matter (TEOM) was extracted with a dichloromethane/methanol mixture after drying and sieving the sediments and identified by gas chromatography–mass spectrometry. The TEOM comprised n-alkanes (302.6 ± 446.7 ng·g⁻¹ and 64 ± 50 ng·g⁻¹), hopanes (29.8 ± 132.3 ng·g⁻¹ and 1.0 ± 2.5 ng·g⁻¹), steranes (0.0 and traces), n-alkanoic acids (745.8 ± 799.6 ng·g⁻¹ and 120.7 ± 92.0 ng·g⁻¹), n-alkanols (457.4 ± 1085.6 ng·g⁻¹ and 49.7 ± 32.3 ng·g⁻¹), polycyclic aromatic hydrocarbons (PAHs) (54.5 ± 96.8 ng·g⁻¹ and 7.8 ± 8.5 ng·g⁻¹), and phthalates (185.3 ± 169.9 ng·g⁻¹ and 67.4 ± 70.4 ng·g⁻¹) in the Al-Qahma and Al-Wajh lagoon sediments, respectively. The percentages of the various sources relative to total aliphatic and cyclic hydrocarbon concentrations were 6.9 ± 6% for terrestrial plants, 53.7 ± 19% for algae, 10 ± 2% for microbial, 16 ± 12% for petroleum, and 13.4 ± 7 for plasticizer inputs in Al-Qahma lagoon. In Al-Wajh lagoon, they were 9.7 ± 4% for terrestrial plants, 30.8 ± 14% for algae, 25.2 ± 5% for bacteria, 11.2 ± 3% for petroleum, and 23.1 ± 11% for plasticizers. Full article

Little is known concerning terpenoids produced by members of the fungal order Ophiostomales, with the member Harringtonia lauricola having the unique lifestyle of being a beetle symbiont but potentially devastating tree pathogen. Nine known terpenoids, including six labdane diterpenoids (1–6) and three hopane triterpenes (7–9), were isolated from H. lauricola ethyl acetate (EtOAc) extracts for the first time. All compounds were tested for various in vitro bioactivities. Six compounds, 2, 4, 5, 6, 7, and 9, are described functionally. Compounds 2, 4, 5, and 9 expressed potent antiproliferative activity against the MCF-7, HepG2 and A549 cancer cell lines, with half-maximal inhibitory concentrations (IC₅₀s) ~12.54–26.06 μM. Antimicrobial activity bioassays revealed that compounds 4, 5, and 9 exhibited substantial effects against Gram-negative bacteria (Escherichia coli and Ralstonia solanacearum) with minimum inhibitory concentration (MIC) values between 3.13 and 12.50 μg/mL. Little activity was seen towards Gram-positive bacteria for any of the compounds, whereas compounds 2, 4, 7, and 9 expressed antifungal activities (Fusarium oxysporum) with MIC values ranging from 6.25 to 25.00 μg/mL. Compounds 4, 5, and 9 also displayed free radical scavenging abilities towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide (O²⁻), with IC₅₀ values of compounds 2, 4, and 6 ~3.45–14.04 μg/mL and 22.87–53.31 μg/mL towards DPPH and O²⁻, respectively. These data provide an insight into the biopharmaceutical potential of terpenoids from this group of fungal insect symbionts and plant pathogens. Full article

Kazakhstan ranks as the 12th largest oil producer globally and boasts a diverse range of crude oils. This research introduces a method for distinguishing between the different types of crude oils based on biomarker analysis of 28 crude oils from Western and Southern Kazakhstan using gas chromatography-mass spectrometry. Biomarkers serve as valuable tools, especially in forensic investigations of oil spills. These biomarkers effectively retain a significant portion of the original natural product’s carbon structure, providing crucial evidence regarding the origin and identity of the oils under examination. This study identifies a set of biomarkers, including pristine, phytane, n-C₁₇ and n-C₁₈ alkanes, hopanes, bisnorhopanes, iso-copalanes, pregnane, androstane, allopregnane, homopregnane, cholestane, and stigmastane. By examining ratios such as pristane/phytane, pristane/n-C₁₇ alkane, tricyclic/pentacyclic terpanes, and hopane, as well as the distribution of steranes, it was deduced that crude oils from West Kazakhstan exhibited resilience to biodegradation. These findings showed that gas chromatography-mass spectrometry is an effective method for oil biomarkers determination, especially because it provides efficient separation and identification. Additionally, this study delved into the origin conditions and maturity of these oils, contributing to a deeper understanding of their characteristics and analysis that is simple to use and available worldwide. Full article

The Tarim Basin, a significant region of coal-derived gas generation in China, has widely dispersed coal measure source rocks, especially in the Kuqa Depression. The typical coal measure strata from the Kuqa River and Kapushaliang River sections in the Kuqa Depression were systematically sampled. According to a conventional geochemical analysis (including materials and lithology), a total of 25 typical coal measure source rock samples were chosen for chromatography and chromatography–mass spectrometry examination. It was demonstrated that there were significant discrepancies in the coal source rock samples, particularly the coal rock from the Kuqa River section and the Kapushaliang River section. The specific performance of the Kuqa River section was characterized by a high Pr/Ph ratio (up to 9.29), a low gammacerane ratio, a low abundance of tricyclic terpane, and an “L”-type distribution of regular steranes, all of which are consistent with the properties of humic coal found in freshwater lakes that have undergone partial oxidation. The Kapushaliang River section, by contrast, exhibited a low Pr/Ph ratio (<1.0), a high gammacerane ratio, a concentration of tricyclic terpane comparable to that of hopane, and a distribution of regular steranes in a “V” shape, all of which indicate a strongly reduced saline water environment. Additionally, the degree of thermal evolution is not the key factor resulting in the above biomarker diversity within the CSRs, which was supported by the poor correlation between the maturity parameters (Ro%, Tmax °C), the sedimentary environment-related parameters (such as Pr/Ph and Ga/C₃₁H), and the biogenic-related parameters (such as ∑tricyclic terpane/∑ hopane and ∑sterane/∑hopane). A comparative analysis suggested that transgression-related changes in the redox conditions and parent materials triggered the biomarker diversity within the CSRs, resulting in a large difference in the hydrocarbon-forming parent materials between the two abovementioned outcrop sections. These might provide some insight for hydrocarbon exploration from CSRs, which have been attracting increasing attention in China, with proven coal reserves are ranked first in the world. Full article

Exhaust emissions from ships have garnered significant attention because of their impact on global climate change, deterioration of air quality, and potential risks to human health. Consequently, it is necessary and urgent to quantify the gaseous and particulate emission factors (EFs) of ships in a local area. In order to supplement native EF profile data, an inland cargo ship in China was selected for measuring gaseous and particle pollutants under real-world operation modes. The fuel-based EFs of carbon dioxide, carbon monoxide (CO), nitrogen oxides, and hydrocarbons (THC) were 2965–3144 g/kg, 8.04–83.53 g/kg, 64.51–126.20 g/kg, and 3.90–23.35 g/kg, respectively. The maximum values of CO EF and THC EF were achieved under idling mode, which were 10.4 and 5.3 times those observed under cruising (500 rpm) mode, as extremely poor engine loads under idling mode can result in low temperature, low pressure, and uneven mixture of air and fuel. Organic carbon and element carbon were identified as the most abundant compositions of particulate matter (PM). Ions and elements were primarily dominated by SO₄²⁻ and S, which can be attributed to the utilization of fuels with high sulfur content. Additionally, hopanes (dominated by 17α(H),21β(H)-Hopane and 17α(H),21β(H)-29-Norhopane) and fatty acids (dominated by n-Hexadecanoic acid and n-Octadecanoic acid) have the potential to serve as tracers for ship exhaust emissions. Pyrene and fluoranthene, two EPA priority polycyclic aromatic hydrocarbons (PAHs), were identified as the major constituents of PAHs and accounted for 50% of total PAHs. This finding also provides an explanation for the significant contribution of four-ring PAHs to the total PAHs mass. Full article