Carbon Content Research Articles

Temperature sensitivity of soil respiration declines with climate warming in subalpine and alpine grassland soils

AbstractWarming as a climate change phenomenon affects soil organic matter dynamics, especially in high elevation ecosystems. However, our understanding of the controls of soil organic matter mineralization and dynamics remains limited, particularly in alpine (above treeline) and subalpine (below treeline) grassland ecosystems. Here, we investigated how downslope (warming) and upslope (cooling) translocations, in a 5-years reciprocal transplanting experiment, affects soil respiration and its temperature sensitivity (Q10), soil aggregation, and soil organic matter carbon (C) and nitrogen (N) composition (C/N ratio). Downslope translocation of the alpine (2440 m a.s.l.) and subalpine (1850 m a.s.l.) to the lowland site (350 m a.s.l.) resulted in a temperature change during the growing seasons of + 4.4K and + 3.3K, respectively. Warming of alpine soils (+ 4.4K) reduced soil organic carbon (SOC) content by 32%, which was accompanied by a significant decrease of soil macroaggregates. Macroaggregate breakdown induced an increased respiration quotient (qCO2) by 27% following warming of alpine soils. The increase in qCO2 respiration was associated with a significant decrease (from 2.84 ± 0.05 to 2.46 ± 0.05) in Q10, and a change in soil organic matter composition (lower C/N ratios). Cooling did not show the opposite patterns to warming, implying that other mechanisms, such as plant and microbial community shifts and adaptation, were involved. This study highlights the important role of SOC degradability in regulating the temperature response of soil organic matter mineralization. To predict the adverse effect of warming on soil CO2 release and, consequently, its negative feedback on climate change, a comprehensive understanding of the mechanisms of C storage and turnover is needed, especially at high elevations in the Alps that are particularly affected by rising temperatures.

Investigating the physical characteristics and antibacterial properties of the cork back from Quercus variabilis

This study presents for the first time results on structure feature, basic physical properties, torrefaction treatment, adsorption property, component content and antimicrobial properties of the cork back from Quercus variabilis. The cork back consisted of numerous white stone cell bundles with a dense and firm texture and irregularly shaped cells exhibiting considerable deformation and wrinkles. The cork back had the average density of 0.37 g/cm3, average hardness of 91.60 HA and the average thickness was 31.44 % of the total cork thickness. The average colorimetric parameters values of L*, a*, and b* of the cork back were 21.92, 2.34, and 6.42, respectively. Increasing torrefaction temperature increased the quality loss of the cork back, decreased energy yield and volatile matter content, and increased ash and fixed carbon content. With the elevation of fixed carbon, the higher calorific value of the cork back also increased. Following high-temperature torrefaction at 300 °C, the higher calorific value of cork back was 24.00 MJ/kg which increased by 30.29 % compared to untreated cork back. The cork back powder had significant adsorption performance for methylene blue and the maximum adsorption capacity could reach 511.61 mg/g. Compared with cork，the cork back had a high content of lignin and polysaccharides, with a suberin content of only 4.07 %. The total extractives content in cork back was 7.49 %. The water extractives of the cork back exhibited the most significant inhibitory effect on Escherichia coli, with the lowest inhibitory concentration recorded at 2 mg/mL. This research offers essential data for the processing and utilization of the cork back, which contributes to enhance the utilizing efficiency of cork resources.

Regulating Composition and Structure of Coal-based Graphene and Its Electrochemical Characteristics

Abstract Coal, a carbon-rich mineral with plentiful reserves, serves not only as a fuel but also as a raw material, presenting lower pollution emissions in the latter use. From a materials chemistry standpoint, coal is a viable raw material for graphene production. This study develops a promising and sustainable method to convert coal into graphene, leveraging its unique macromolecular aromatic structure and high carbon content. The investigation includes an analysis of the lateral size, morphology, and chemical composition of coal-derived graphene using techniques such as X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and optical microscopy. Results confirm that coal can effectively replace natural graphite flakes in graphene production, with the derived graphene featuring 3-6 exfoliated layers and an oxygen content below 5.5%. While the graphene from coal shares a similar morphology to that derived from graphite, it exhibits more structural defects. Interestingly, the macroscopic size of the coal does not influence the microscopic composition and structure of the graphene. However, the thermal reduction method for oxidized graphene proves more effective at repairing structural defects than chemical reduction. Employing coal-derived graphene as a supercapacitor electrode demonstrates excellent cycling stability and ultra-high capacitance storage capacity. The H-CG-325 shows the highest discharge area-specific capacitance across various current densities. At an increased current density of 10 A/g, the H-CG-325 maintains 80.6% of its initial capacitance of 79 F/g observed at 1 A/g. Electrochemical tests reveal that coal-based graphene holds significant potential as a supercapacitor material, indicating promising applications in energy storage and conversion.

Biochar affects organic carbon composition and stability in highly acidic tea plantation soil

Biochar amendments are effective in stabilizing soil aggregates and improving soil organic carbon (SOC) content. However, the effects of biochar on highly acidic soil and their relation with soil SOC stability remain understudied. The study aimed to investigate the impact of biochar on changes of aggregate distribution and SOC stability in a highly acidic tea plantation soils over an eight-year period. Soil samples were collected from plots with varying biochar application amounts (0, 2.5 t ha−1, 5 t ha−1, 10 t ha−1, 20 t ha−1 and 40 t ha−1). The content of SOC, iron bound organic carbon (OC-Fe), particulate organic carbon (POC), mineral-associated organic carbon (MAOC) and the functional group composition of SOC was analyzed. The results indicated that in the biochar application treatments, the value of soil pH, SOC, POC and MAOC contents were increased from 3.92 to 4.28, 6.68%–187.02%, 8.31%–66.78% and 13.07%–236.47% respectively, compared with CK, while the content of macro-aggregate (particle size>0.25 mm) and soil aggregates mean weight diameter (MWD) significantly increased with higher biochar application amounts. But dissolved organic carbon (DOC) and OC-Fe content exhibited downward trend, decreased from 2.43% to 6.97% and 4.18%–19.91%. Furthermore, aromatic-C levels increased, with increased biochar application amounts. The integration of biochar not only bolstered soil aggregate stability but also amplified the presence of aromatic-C, thereby enhancing the resilience of organic carbon in highly acidic tea garden soil (BC40 > BC20 > BC5>BC2.5 > BC10 > CK), with increases ranging from 6% to 47%. The principal component analysis and structural equation modeling identified soil pH, TN, SOC, POC, MAOC, R > 0.25 and MWD as key factors of soil organic carbon stability. These findings provide crucial insights into the mechanism underlying biochar's efficiency in fortifying organic carbon stability, particularly in the context of highly acidic soil.

Characterization of bio-crude produced by graphene carbon tetranitrate catalyzed hydrothermal liquefaction and ultrasonication of Ulva prolifera mixed Chicken waste

<p style="text-align:justify;"><span style="font-family:"Times New Roman",serif;font-size:12pt;line-height:200%;">The utilization of macroalgae, specifically </span><em><span style="font-family:"Times New Roman",serif;font-size:12pt;line-height:200%;">Ulva prolifera</span></em><span style="font-family:"Times New Roman",serif;font-size:12pt;line-height:200%;">, for the manufacture of bio-crude demonstrates great potential as a viable alternative to conventional fossil fuels. This is mostly owing to its abundant availability and renewable characteristics, making it an optimal choice for bio-oil production. This study examined the synthesis of bio-crude through the Hydrothermal Liquefaction (HTL) method. The combination of Ultra-sonicated </span><em><span style="font-family:"Times New Roman",serif;font-size:12pt;line-height:200%;">Ulva prolifera</span></em><span style="font-family:"Times New Roman",serif;font-size:12pt;line-height:200%;">, Chicken Waste, and water facilitated the transformation of the moist biomass into Bio-crude. The study also examined the influence of process parameters, including the optimal operational temperature, retention time, and feedstock mixing ratio (275 <sup>o</sup>C, 30 minutes, and 1:4 ratio) for the graphene-C<sub>3</sub>N<sub>4 </sub>catalyst, KOH. The study's findings verified that a significant amount of bio-oil, specifically 23.5wt.% based on dry weight measurements, was successfully produced. The bio-oil mostly consists of alcohols, esters, phenols, ketones, and acidic chemicals. Furthermore, the bio-oil exhibited a significant heating value of 38.15 MJ/kg, which can be attributed to the presence of carboxylic acid groups and aliphatic hydrocarbons. Furthermore, the carbon content in the bio-oil was found to be double that of the macroalgae used as feedstock. Additionally, the heating value of the bio-oil was shown to be 2.5 times greater than that of the macroalgae. Hydrothermal liquefaction may be used to efficiently create bio-oil from </span><em><span style="font-family:"Times New Roman",serif;font-size:12pt;line-height:200%;">Ulva prolifera</span></em><span style="font-family:"Times New Roman",serif;font-size:12pt;line-height:200%;">, a third-generation fuel that has great potential as an environmentally benign and sustainable energy source.</span></p>

Effects of Two Different Size ZnO Nanoparticles on the Growth of Aspergillus oryzae

Two different kinds of ZnO nanoparticles (NPs) with distinct particle sizes were synthesized by a precipitation method. For the first time, the effects of two distinct sizes ZnO NPs on the growth, photoluminescence properties and kojic acid (KA) yield of Aspergillus oryzae (A. oryzae) were examined. The findings showed that ZnO-A and -B NPs, with average particle sizes of 11.93 nm and 34.41[Formula: see text]nm, respectively, exhibited a hexagonal crystal structure. It was found that when the concentration of NPs was below 100[Formula: see text][Formula: see text]g/mL, ZnO NPs were nontoxic and served as activators to stimulate the growth of A. oryzae, and the biomass of solid and liquid medium, the total integral emission intensity, the content of extracellular protein and total organic carbon and KA yield of A. oryzae grown with ZnO-A (ZnO-B) NPs were about 2.19 (1.97), 2.47 (1.56), 1.67 (1.16), 2.45 (1.95), 0.47 (0.50) and 2.07 (1.37) times more than that of control sample (without NPs), respectively.

Phosphogypsum with Rice Cultivation Driven Saline-Alkali Soil Remediation Alters the Microbial Community Structure

The improvement of saline-alkali land plays a key role in ensuring food security and promoting agricultural development. Saline soils modifies the response of the soil microbial community, but research is still limited. The effects of applying phosphogypsum with rice cultivation (PRC) on soil physicochemical properties and bacterial community in soda saline-alkali paddy fields in Songnen Plain, China were studied. The results showed that the PRC significantly improved the physicochemical properties of soil, significantly reduced the salinity, increased the utilization efficiency of carbon, nitrogen, and phosphorus, and significantly increased the activities of urease and phosphatase. The activities of urease and phosphatase were significantly correlated with the contents of total organic carbon and total carbon. A redundancy analysis showed that pH, AP, ESP, HCO3−, and Na+ were dominant factors in determining the bacterial community structure. The results showed that PRC could improve soil quality and enhance the ecosystem functionality of soda saline-alkali paddy fields by increasing nutrient content, stimulating soil enzyme activity, and regulating bacterial community improvement. After many years of PRC, the soda-alkali soil paddy field still develops continuously and healthily, which will provide a new idea for sustainable land use management and agricultural development.

Sugarcane straw biochar: effects of pyrolysis temperature on barite dissolution and Ba availability under flooded conditions

AbstractReductive dissolution of barium (Ba) sulfate in wetland soils may increase Ba bioavailability in the environment, yet no information is available regarding Ba remediation using biochar. This study investigated the effectiveness of sugarcane (Saccharum officinarum) straw biochar pyrolyzed at 350 °C (BC350), 550 °C (BC550), and 750 °C (BC750) in inhibiting barite dissolution and, consequently, Ba availability in a soil artificially spiked with barite and flooded for 365 days. Increasing pyrolysis temperature alters the carbon structure, and increases dehydration and depolymerization, resulting in more stable biochar that releases less DOC (8.6-fold decrease from BC350 to BC750). Additionally, high-temperature biochar (BC750) had 1.7 times higher carbon (C) content, 2.4 times higher ash content, and a 13.1 times greater specific surface area (SSA) than low-temperature biochar (BC350). Amending soil with BC750 increased pH but did not promote reducing conditions, and thus did not promote barite dissolution. Conversely, greater DOC in low-temperature biochar, particularly BC350, favored reducing conditions and increased barite dissolution by 23%, with BC550 also showing an 18% increase. This enhancement led to a greater pool of Ba sorbed into more labile exchangeable sites. In summary, pyrolysis temperature affects biochar attributes, which in turn influences the soil geochemical environment and Ba speciation. Low-temperature biochar (BC350) shows potential as an amendment to increase the bioavailable Ba pool in assisted remediation programs, such as biochar-assisted phytoremediation. Graphical Abstract

Microstructural Study of Medieval Crucible Steels from Archaeological Sites in Central and Northwest Asia: Identifying the Bulat

The microstructure of 9th–15th century artifacts made of crucible steel, found at sites in Central and Northwest Asia, is described. Metallographic study of items from settlements and burials with precise data on chronology, location, and accompanying artifacts is important for reconstructing the history of bulat steel and the technology of melting and processing ultra-high-carbon crucible steel. The study of the macro- and microstructure, and the chemical analysis of such items indicate an extremely high content of carbon—1.7–2.1 %. The characteristic feature of their microstructure is a dark matrix with white inclusions of ledeburite and iron carbides. The combination of structural components is reflected in the patterned structure of the metal. These properties suggest that such metal is identical to bulat steel. Findings of macrostructural analysis extend our knowledge of the varieties of this metal, its structural features, phase composition of separate groups of ultra-high-carbon crucible steel, smelting technology, plastic and thermal treatment, and physical properties.

Exotic mangrove Laguncularia racemosa litter input accelerates nutrient cycling in mangrove ecosystems

Exotic plant litter presents different chemical and physical properties relative to native plant litter and alters ecosystem processes and functions that may facilitate exotic plant dispersal. However, these effects are largely unknown, especially within wetland ecosystems. This study examines whether introducing litter from the exotic mangrove Laguncularia racemosa could result in (1) accelerated community litter decomposition rates and increased nutrient cycling rates and (2) microbial community structure changes in the invaded areas. A single decomposition experiment using litterbags was conducted to examine the short-term effects of L. racemosa litter in the native mangrove forest ecosystem. The soil nutrients and microbial communities of Rhizophora stylosa, L. racemosa, and mixed forests were also compared to explore the long-term cumulative effects of L. racemosa litter in native ecosystems. The results indicated that L. racemosa has lower-quality leaf litter than R. stylosa and a significantly faster decomposition rate. This may result from changes in the soil microbial community structure caused by L. racemosa leaf litter input, which favors the decomposition of its own litter. Both the short-term and cumulative effect experiments demonstrated that L. racemosa leaf litter significantly increased the relative abundance of microbes related to litter decomposition, such as Proteobacteria and Bdellovibrionota, and enhanced the alpha diversity of soil fungi, thus creating a microbial environment conducive to L. racemosa leaf litter decomposition. Moreover, the accumulation of soil nutrients was lower under L. racemosa than under R. stylosa over several years. This may be related to the more rapid growth of L. racemosa, which causes soil nutrient absorption and storage within the plant tissues, thereby reducing the soil nutrient content. Inputting exotic mangrove L. racemosa leaf litter reduced the soil blue carbon content, potentially adversely affecting global climate change. L. racemosa may employ a unique strategy to lower soil nutrient levels in native mangroves based on its low-quality leaf litter, thereby weakening the competitive ability of native plants that are intolerant to low-nutrient conditions and enhancing its own competitive advantage to further spread into these areas. In summary, the input of exotic L. racemosa leaf litter accelerates nutrient cycling in local mangroves.

Adsorption Property and Morphology Evolution of C Deposited on HCP Co Nanoparticles

Despite extensive studies of deposited carbon in Fischer–Tropsch synthesis (FTS), an atomic-level comprehension of the effect of carbon on the morphology of cobalt-based FTS catalysts remains elusive. The adsorption configurations of carbon atoms on different crystal facets of hexagonal close-packed (hcp) Co nanoparticles were studied using density functional theory (DFT) calculations to explore the interaction mechanism between C and Co surfaces. The weaker adsorption strength of C atoms on Co(0001), Co(10-10), and Co(11-20) surfaces accounted for lower diffusion energy, leading to the facile formation of C dimers. Electronic property analysis shows that more electrons are transferred from Co surfaces to C atoms on corrugated facets than on flat facets. The deposition of carbon atoms on Co nanoparticles affects surface energy by forming strong Co-C bonds, which causes the system to reach a more energetically favorable morphology with an increased proportion of exposed Co(10-12) and Co(11-20) areas as the carbon content increases slightly. This transformation in morphology implies that C deposition plays a crucial role in determining the facet proportion and stability of exposed Co surfaces, contributing to the optimization of cobalt-based catalysts with improved performance.

Effect of SiCN thin film interlayer for ZnO-based RRAM.

This study investigates the effect of silicon carbon nitride (SiCN) as an interlayer for ZnO-based resistive random access memory (RRAM). SiCN was deposited using plasma-enhanced chemical vapor deposition (PECVD) with controlled carbon content, achieved by varying the partial pressure of tetramethylsilane (4MS). Our results indicate that increasing the carbon concentration enhances the endurance of RRAM devices but reduces the on/off ratio. Devices with SiCN exhibited lower operating voltages and more uniform resistive switching behavior. Oxygen migration from ZnO to SiCN is examined by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses, promoting the formation of conductive filaments (CFs) and lowering set voltages. Additionally, we examined the impact of top electrode oxidation on RRAM performance. The oxidation of the Ti top electrode was found to reduce endurance and increase low resistive state (LRS) resistance, potentially leading to device failure through the formation of an insulating layer between the electrode and resistive switching material. The oxygen storage capability of SiCN was further confirmed through high-temperature stress tests, demonstrating its potential as an oxygen reservoir. Devices with a 20 nm SiCN interlayer showed significantly improved endurance, with over 500 switching cycles, compared to 62 cycles in those with a 5 nm SiCN layer. However, the thicker SiCN layer resulted in a notably lower on/off ratio due to reduced capacitance. These findings suggest that SiCN interlayers can effectively enhance the performance and endurance of ZnO-based RRAM devices by acting as an oxygen reservoir and mitigating the top electrode oxidation effect.

Unveiling the main drivers of tree decline in Zagros semi-arid forests

Abstract Tree decline in arid and semi-arid forest ecosystems causes severe socioeconomic and ecological problems and thus needs to be thoroughly quantified and monitored across space and time. This study investigates tree and forest decline in Iran’s Zagros forests, considering environmental factors (e.g. topographic, soil, and climatic variables). We used field data from Chaharmahal-and-Bakhtiari (a study area covering 165 km2) and environmental data derived from freely available databases. Relationships between tree, forest decline, and environmental data were analyzed using generalized additive models. Our findings reveal that slope and the BioClim-16 variable (precipitation of the wettest quarter) significantly influence tree decline across various decline classes (P-values: slope = .009, BioClim-16 = .02). The best multivariate model for forest decline incorporated soil organic carbon and silt as predictive variables, with soil organic carbon emerging as the key factor (P-value = .04). Additionally, a spectral analysis of bare soil in declining and non-declining areas consistently demonstrated reduced reflectance values in declining regions across 10 Sentinel-2 bands, with VNIR-3, SWIR-2, red, green, and blue bands consistently showing significant differences as unveiled by the Wilcoxon test in all seasons except winter. These reduced reflectance values may indicate that forests stocked on soils with larger grain size (a higher fraction of sand) and/or higher organic carbon content may be more vulnerable to decline. This study contributes to our hitherto understanding of the main drivers of tree and forest decline in semi-arid forests, among others underscoring the potential utility of the spectral properties of bare soil in sparse semi-arid forests to predict the likelihood of tree decline.

FEATURES AND EXPERIENCE OF CONVERTING GAS-OIL BOILERS OF INDUSTRIAL CHP PLANTS TO BURNING BIOMASS AND SUB-BITUMINOUS COAL

The paper examines the features of biomass as a fuel and substantiates that for agrobiomass waste with a high content of alkali metal oxides and slag properties of ash, it is more appropriate to burn it in a dense bed in the form of pellets, which ensures a temperature at the exit from the furnace of no more than 900 °C, a low part of fly ash and low content of unburned carbon in it, and so eliminates the risk of smoldering deposits with their melting and slagging. Technical solutions are given and the experience is presented of gas and oil boilers of CHP plants of sugar factories reconstruction with their transfer to the burning of biomass and/or coal in a dense bed on a direct-flow grate with the replacement of the air heater with air-water heater, with the addition of stages of the boiling economizer to compensate for the decrease in the heat perception of the furnace screens, maintaining the overall height of the boiler and the plane of the boiler cell. The reconstruction of boilers according to the developed technical solutions is possible to perform in the interval between production seasons, its implementation on boilers BKZ-75 GMA of Radekhiv and Chortkiv sugar factories allowed to achieve acceptable technical, economic and environmental indicators and ensured payback due to the difference in commercial prices of gas and of agrobiomass pellets. It is proposed to replicate the positive experience in the creation of decentralized regulating thermal generation capacities of the country. Bibl. 30, Fig. 3, Tab. 4.

Chemometric Discrimination of the Geographical Origin of Rheum tanguticum by Stable Isotope Analysis

Rheum tanguticum is one of the primary rhubarb species used for food and medicinal purposes, and it has recently been gaining more attention and recognition. This research represents the first attempt to use stable isotopes and elemental analysis via IRMS to identify the geographical origin of Rheum tanguticum. A grand total of 190 rhubarb samples were gathered from 38 locations spread throughout the provinces of Gansu, Sichuan, and Qinghai in China. The carbon content showed a decreasing trend in the order of Qinghai, followed by Sichuan, and then Gansu. Nitrogen content was notably higher, with Qinghai and Sichuan displaying similar levels, while Gansu had the lowest nitrogen levels. Significant differences were noted in the δ13C (−28.9 to −26.5‰), δ15N (2.6 to 5.6‰), δ2H (−120.0 to −89.3‰), and δ18O (16.0‰ to 18.8‰) isotopes among the various rhubarb cultivation areas. A significant negative correlation was found between %C and both longitude and humidity. Additionally, δ13C and δ15N isotopes were negatively correlated with longitude, and δ15N showed a negative correlation with humidity as well. δ2H and δ18O isotopes exhibited a strong positive correlation with latitude, while significant negative correlations were observed between δ2H and δ18O isotopes and temperature, precipitation, and humidity. The LDA, PLS-DA, and k-NN models all exhibited strong classification performance in both the training and validation sets, achieving accuracy rates between 82.1% and 91.7%. The combination of stable isotopes, elemental analysis, and chemometrics provides a reliable and efficient discriminant model for accurately determining the geographical origin of R. tanguticum in different regions. In the future, the approach will aid in identifying the geographical origin and efficacy of rhubarb in other studies.

Sedimentary factors controlling the organic matter enrichment in oil shale, Seyitömer Lacustrine Basin, Western Anatolia: New implications from organic and inorganic geochemistry

AbstractWestern Anatolia, an important segment of the Alp‐Himalayan Belt, hosts numerous Neogene lacustrine basins with potential oil shale reserves surpassing 1.6 billion tonnes. Among these basins, the Seyitömer Basin (Kütahya) stands out, containing oil shales that are intercalated with claystone, marl, limestone and coal layers. This study presents a comprehensive dataset of organic and inorganic chemistry to gain insight into the palaeoclimate and palaeoenvironmental factors that control the enrichment of organic matter. The studied samples exhibit high total organic carbon contents, averaging 12.85% (ranging from 2.22 to 36.21%), high hydrogen indices (486–812 mgHC/g rock) and low oxygen indices (33–70 mgCO2/g total organic carbon), indicating their substantial hydrocarbon‐source potential. These characteristics indicate predominantly ‘excellent’ to occasionally ‘very good’ source rock qualities and very high oil potential. Their pyrolysis, gas chromatography and gas chromatography–mass spectrometer parameters indicate an immature‐early mature characteristic for Seyitömer oil shale samples. They comprise dominantly Type‐I kerogen with minor Type‐II kerogen and lacustrine algal organic matter. Their sedimentological characteristics, along with various geochemical values, such as total organic carbon versus S, B versus Ga and dibenzothiophene/phenanthrene, reveal a moderately deep fresh/brackish to saline lacustrine environment. The Ga/Rb, K/Al and Sr/Cu ratios suggest dominantly humid and warm climate conditions, occasionally interrupted by periods of less humidity. The prevalence of warm and humid climate conditions leads to intense chemical weathering processes, supported by high Chemical Index of Alteration and low Rb/Sr ratios in the associated oil shale samples. Intense chemical weathering and high runoff resulted in dissolved nutrient enrichment, promoting ecological dynamics favourable to increased productivity. Their low Pr/Ph and Mo/total organic carbon ratios, high Ni/Co ratio and, relatively low MoEF/UEF ratio, along with well‐developed lamination of the oil shales, indicate the presence of anoxic conditions in the bottom water. These anoxic conditions would have facilitated the preservation potential of organic matter in the samples. Thus, the palaeoclimate conditions integrated with sedimentary factors have an important role in the ecological dynamic and physical–chemical environmental conditions, ultimately contributing to the organic matter enrichment of the studied samples. This work provides a case study to better understand the sedimentary factors controlling organic matter enrichment in the lacustrine basins of the Alp‐orogenic belt.

Influence of pyrolysis temperature on biochar properties: Applications as a reinforcing filler in sbr and epdm elastomeric compounds

This study investigates the effect of pyrolysis temperature on the properties of biochar derived from Pinus spp. wood waste and its application as a reinforcing filler in styrene-butadiene rubber (SBR) and ethylene-propylene-diene monomer (EPDM) elastomeric compounds. Biochar was produced at 400°C and 900°C and its effects on the mechanical properties of the elastomers were analyzed. The results indicate that biochar produced at 900°C has higher fixed carbon content and lower volatile matter, resulting in improved mechanical properties such as tensile strength and elongation at break compared to biochar produced at 400°C. Despite a lower specific surface area, the irregular surface structure of biochar enhances its interaction with elastomers, providing a semi-reinforcement. This study highlights the potential of high-temperature biochar as a sustainable alternative to conventional fillers such as carbon black, contributing to the development of environmentally friendly materials from biomass waste. The results support further exploration of the role of biochar in elastomer applications, highlighting its environmental and mechanical benefits.

Metals geochemistry and ecological risk assessment in lateritic soils and their transfer to tea plants

ABSTRACT Tea plant cultivation has been demonstrated to change the physicochemical properties of soils and metal bioavailability. The present study reported the geochemistry of four selected metals (Fe, Mn, Cr, and Ni) in lateritic soil cores regarding various depths cultivated with tea plants of different ages (3, 6, and 10 years old). The ecological risk and bioaccumulation of these metals in tea plants were also evaluated. The results indicate the acidic property of tea plant cultivation soils (pH < 4.5) and highlight further soil acidification due to long-term cultivation. The soils were strongly affected by farming methods and showed high levels (average from all soil cores) of total organic carbon contents (4.0% w/w), total nitrogen (2806 mg kg−1), and total phosphorus (1730 mg kg−1). We suggest that the selected metals originated naturally, supported by a high percentage in residual fractions from the results of soil sequential extraction (over 95% for Mn, Fe, and Ni and ∼ 90% for Cr). These metals exhibited no ecological risk to the adjacent environment. Mn showed the highest bioavailability, possibly due to the acidic soils and nitrogen fertiliser applications, increasing the release of Mn from soils. Mn also exhibited the highest bioconcentration factor (BCF) among four metals and 2.4 ÷ 6.5-folds higher BCFs in tea leaves than in roots. Despite the dominant content of Fe in soils (average of 20% w/w), Fe indicated lower amounts in tea leaves than Mn (average of 513 mg kg−1 vs 1354 mg kg−1). This could be attributed to the formation of Fe-rich root coatings on the tea plant root surface as a barrier to prevent Fe from translocating to other higher tea plant parts. Ni and Cr, as potentially toxic metals, were found at the lowest contents in tea leaves with low BCFs, indicating consumer safety in terms of exposure by these metals.

Incorporating date palm fibers for sustainable friction composites in vehicle brakes

The demand for eco-friendly materials in automotive components has spurred research into natural fibers as sustainable alternatives for brake pads. This study examines the potential of date palm fibers, particularly the palm frond midrib (PFM), in brake pad composites. The effects of epoxy, PFM, and calcium carbonate on the composites’ mechanical and tribological properties were analyzed. The optimal formulation (25% epoxy, 30% PFM, 35% calcium carbonate) exhibited superior properties, including a hardness of 87 HRB, wear rate of 1.5E-03 mg/mm, and COF of 0.73, surpassing commercial pads. Additionally, an inverse relationship between PFM/calcium carbonate content and compressibility was observed, with increased calcium carbonate enhancing wear resistance. This research underscores the potential of utilizing date palm resources in eco-friendly brake manufacturing, reducing the environmental and health impacts of traditional materials.

Combined Quantification and Characterization of Dissolved Organic Matter by Liquid Chromatography-Mass Spectrometry Using Charged Aerosol Detection.

Dissolved organic matter (DOM) is a complex mixture of thousands of molecular formulas comprised of an unknown number of chemical compounds, the concentration and composition of which are critical to ecosystem function and biogeochemical cycling. Despite its importance, our understanding of the DOM composition is lacking. This is principally due to its molecular complexity, which means that no single method is capable of describing DOM in its entirety. Quantification is typically done by proxy (e.g., relative to carbon content) and does not necessarily match well to compositional data, due to incomplete analytical windows and selectivity of different analytical methods. We present an integrated liquid chromatography (LC)-diode array detector (DAD)-charged aerosol detector (CAD)-mass spectrometry (MS) pipeline designed to both characterize and quantify solid-phase extractable DOM (SPE-DOM) in a single analysis. We applied this method to a set of eight Swedish water bodies sampled in the summer and winter. Chromophoric SPE-DOM was proportionally higher in samples with higher SPE-DOM concentrations but remained relatively consistent between sampling occasions. Ionizable SPE-DOM was relatively consistent across sites but was proportionally higher in summer. Overall, the carbon content of DOM was very consistently ∼40% across sites in both summer and winter. These findings suggest that SPE-DOM concentration at these sites is driven by (presumably allochthonous) chromophoric inputs, with an increased relative contribution in summer of material that is more ionizable and less chromophoric and may be either autochthonous or selectively enriched from allochthonous sources. Thus, with minimal additional effort, this method provided further compositional insights not attained by any single analysis in isolation.