Carbonaceous Compounds Research Articles

A reaction-dissolution strategy for designing solid electrolyte interphases with stable energetics for lithium metal anodes

The spatial variations in chemical composition and transport properties of the interphase formed on reactive metal electrodeposits dictate the stability and reversibility of electrochemical cells that use reactive metals as anodes. Here we report on the influence of carbonate and fluorinated electrolytes infused with ethers as additives on the physical-chemical characteristics and reversibility of metallic lithium (Li) during early stages of electrodeposition and later stages of deep cycling of Li metal anodes. We show that a feasible strategy for achieving and sustaining kinetically enhanced interphases through the cycle life of Li electrodeposits is by simultaneous use of sacrificial electrolyte components that undergo electroreduction to enrich the interphase with fluorinated species in tandem with cleaning electrolyte components that promote dissolution and removal of less desirable carbonaceous compounds. We demonstrate that this approach translates to high electrochemical reversibility during deep cycling of the Li metal anode and improved performance of Li metal batteries. • Rational design of liquid carbonate/fluorinated electrolytes with ether additive • Study of physiochemical characteristics and reversibility of metallic lithium (Li) • Employing reaction-dissolution strategy to enhance reversibility of Li anode • Demonstrating practical Li metal batteries with exceptional performance The rechargeability and stability of lithium metal batteries (LMBs) is affected by the interphase between the lithium metal anode and the electrolyte. Biswal et al. report rational selection of liquid electrolyte components to create, refresh, and sustain a kinetically enhanced interphase on the lithium metal anode through the cycle life of LMBs.

Effect of non-thermal plasma in the activation and regeneration of 13X zeolite for enhanced VOC elimination by cycled storage and discharge process

A non-thermal plasma (NTP) discharge is used in this study for the activation and regeneration of MS-13X pellets packed in a MS-13X & glass beads packed bed dielectric barrier discharge (DBD) reactor. NTP activation (in-situ) of MS-13X efficiently removes the adsorbed carbonaceous compounds and moisture resulting in an improved VOC adsorption. In addition, NTP exposure is used for the regeneration of the used MS-13X for cycled storage and discharge (CSD) removal of VOC from air. The amount of adsorbed toluene, products formed and the surface and bulk properties of the regenerated used MS-13X shows complete regeneration of used MS-13X. Finally, the stability of MS-13X during 10 cycles of CSD shows no degradation in performance. Thus, NTP exposure is proven to be successful for both the activation and regeneration of MS-13X pellets used for cyclic CSD process.

Magnetically separable Ni-based robust nanocatalyst for hydrogenation of substituted aromatics in renewable bio-kerosene

The magnetically separable Ni/NiO nanocatalyst was synthesized for hydrogenation of substituted aromatics in renewable biokerosene fuel. The catalyst showed acidity of 0.21 mmol/g and ferromagnetic character. The catalytic activity was compared with the traditional noble metal-based catalysts (Pd/NiO, Ni/Al2O3, Pd/Al2O3, and Pt/Al2O3). Among all the catalysts, the non-noble metal catalysts (Ni/NiO, Ni/Al2O3) showed complete conversion (100%) of aromatics to cycloalkanes at the optimal reaction conditions of temperature = 150 °C, Pressure = 100 bar, catalyst mass = 0.6 g, and reaction time = 14 hr. The activation energy for the Ni/NiO catalyst was 51 kjmol−1, similar to Ni/Al2O3 (53 kjmol−1). The coke deposition was much lower for Ni/NiO (<1 wt%) which was lower than Ni/Al2O3 catalyst. Furthermore, FTIR analysis also confirmed the absence of any observable carbon deposition in the used Ni/NiO catalyst while spent Ni/Al2O3 showed prominent peaks due to deposited carbonaceous compounds.

Application of Black Liquor Derived Carbonaceous Compound as Fuel in Direct Carbon Fuel Cell

Direct carbon fuel cell (DCFC) with higher power efficiency and lesser emissions is being viewed as a potential clean energy source. The application of renewable biochar as fuel for DCFC is found to be feasible to replace coal or carbon black for power generation. Black liquor from the paper production might be a suitable fuel source for DCFC due to its high lignin or carbon content. In this study, the feasibility of using compound extracted from black liquor as fuel source for DCFC was investigated in the aspect of physico-chemical and electrochemical properties. Suitable pyrolysis temperature in producing biochar from black liquor compound was first investigated. Results have shown that fixed carbon and ash content increased slightly with increasing pyrolysis temperature. The ash content is made up of majority of silica as depicted in FESEM-EDX results. Oxygen containing functional group was decomposed under high pyrolysis temperature of 700°C and 800°C. Besides, biochar obtained at 500°C of pyrolysis temperature has given the highest power density of 1.22 mW cm-2 whereas 1.44 mW cm-2 was obtained from coal which was used as the control. Future work on ash removal from the black liquor prior to pyrolysis might improve the potential of black liquor derived compound as a fuel source for DCFC.

A DFT investigation of lithium adsorption on carbonaceous compounds as a potential anode material in lithium-ion batteries

Li atom and Li+ ion adsorptions on carbonaceous compounds of four series i.e., C19H11 (denoted by R23), C25H13 (R34), C31H15 (R45), and C37H17 (R56), and derivatives were investigated using the B3LYP-D3/6–31+G(d,p) method. The thermodynamics of the Li atom and Li+ ion adsorptions on carbonaceous derivatives were obtained using frequency calculations at the same level of theory. The selectivity coefficients of Li in terms of the Li/Li+suggested that R23U, R45U derivatives and their single and double C-vacancy such as [R23U+VC]566, [R45U+VC]65,666, [R45U+2VC]56,566 and [R45U+2VC]56,656 could be used as an anion in a Li-ion battery (LIB) but single C-vacancy defect R56U in form of [R56U+VC]566,666 could be used as the cathode in LIB. The Li/[R23U+VC]566 derivative was suggested to be used as sensing materials for the electrical conductivity measurement of Li atoms.

Highly selective hydrodeoxygenation of wood pallet sawdust pyrolysis oil to methyl phenol derivatives using cobalt and iron on activated carbon supported catalysts

• Effect of Co, Fe, and Co-Fe on AC support was investigated for WPS bio-oil upgrading. • 20 wt% 4Co-1Fe/AC catalyst was optimal with HHV (34.16 MJ/kg) and liquid yield (68.85%) at 350 °C and 60 bar. • Methyl Phenol derivates was the main component in upgraded bio-oil. • The deactivation was occurred by external coke formation and oxidation of metals. The catalytic hydrodeoxygenation (HDO) processes for upgrading pyrolysis bio-oils from wood pallet sawdust (WPS) were studied using activated carbon (AC) as a support of mono- (Co/AC and Fe/AC) and bi-metallic (Co-Fe/AC) catalysts. The effects of the reaction temperature and hydrogen pressure on products and high heating value (HHV) were systematically investigated. At 350 °C and 60 bar, 20 wt% Co/AC showed the highest liquid yield (70.46 wt%) along with HHV of 34.22 MJ/Kg. Among the tested bimetallic catalysts, comparable liquid yield (68.85 wt%) and HHV (34.16 MJ/kg) were achieved with 20 wt% 4Co-1Fe/AC catalyst. Methyl phenol derivatives were found to be the main component in upgraded bio-oil. The carbon number of the upgraded bio-oil was mainly distributed in C 5 –C 11 fraction, especially with the C 8 component (20.40 wt%). The catalysts were deactivated by the formation of carbonaceous compounds on the external surface, oxidation of metal species, and blocking of active sites on catalysts.

Research on the electric life evaluation technology of the arc extinguishing chamber of the 550 kV circuit breaker

When the circuit breaker is switched on and off, the phenomenon of arc ablation will occur. Under the action of the electric arc, the surface of the contact is constantly damaged, resulting in deformation and material evaporation. With the increase in the electric arc temperature, the material loss on the contact surface of the circuit breaker increases. In this paper, according to the three major factors affecting the electrical life of the circuit breaker arc extinguishing chamber—the state of the arc contact, the nozzle, and the SF6 gas—the corresponding test detection methods and evaluation methods are proposed. With the continuous accumulation of the breaking current, the effective contact displacement between the arc contacts decreases and the average contact resistance increases. The effective contact displacement decreases exponentially with the increase in the cumulative breaking energy. The content of CF4 can be used not only to characterize the discharge ablation on the surface of the nozzle insulating material but also to characterize the discharge decomposition degree of SF6 in the system by adding carbonaceous compounds. Through the experiment, it is suggested that CF4 should reach 600 µl/l as the threshold for judging whether the arc extinguishing chamber needs maintenance. This method can be extended to the working condition evaluation of the arc extinguishing chamber of other types of the SF6 circuit breaker.

Numerical and experimental study of heterogeneous reactions involving carbonaceous compounds in clay brick firing

Clay bricks have been used as a construction material by humans since thousands of years. Modern brick making however is challenged by the still energy-intensive production, coming together with considerable amounts of greenhouse gas emissions and consequently climate impact. Therefore, the physicochemical fundamentals of the brick firing process should be studied, in order to provide insight to possible technological changes. The present study deals with the heterogeneous chemical reactions, which occur in the thermo-chemical conversion of a clay brick mixture rich in carbonates and blended with organic additives. An integrated solution of the actual mass and heat transfer phenomena resulting from the reactions of carbon-related compounds inside a porous brick body under heat exposure is provided. The partial and global mass balances as well as the heat balance are represented by the relevant differential equations, which were solved using a finite differences method. The chemical kinetics of the carbonates’ calcination and the oxidation of the added organic substance (wood particles) were obtained by thermogravimetric analysis and the results deployed for parameterizing the global reaction model. An accurate description of the effective diffusion coefficients by means of the mean transport-pore model was implemented to the global reaction model. Combustion experiments with cylinder-shaped clay specimens conducted in a fluidized bed lab reactor were used for evaluation of the model. After simple adaptations of the parameterization, the model predictions showed good agreement with the experimental data. Parameter sensitivity analyses and various model tests demonstrate the practical suitability of the presented reaction model for the thermo-chemical process of brick firing.

Organic aerosol compositions and source estimation by molecular tracers in Dushanbe, Tajikistan

To elucidate the molecular composition and sources of organic aerosols in Central Asia, carbonaceous compounds, major ions, and 15 organic molecular tracers of total suspended particulates (TSP) were analyzed from September 2018 to August 2019 in Dushanbe, Tajikistan. Extremely high TSP concentrations (annual mean ± std: 211 ± 131 μg m−3) were observed, particularly during summer (seasonal mean ± std: 333 ± 183 μg m−3). Organic carbon (OC: 11.9 ± 7.0 μg m−3) and elemental carbon (EC: 5.1 ± 2.2 μg m−3) exhibited distinct seasonal variations from TSP, with the highest values occurring in winter. A high concentration of Ca2+ was observed (11.9 ± 9.2 μg m−3), accounting for 50.8% of the total ions and reflecting the considerable influence of dust on aerosols. Among the measured organic molecular tracers, levoglucosan was the predominant compound (632 ± 770 ng m−3), and its concentration correlated significantly with OC and EC during the study period. These findings highlight biomass burning (BB) as an important contributor to the particulate air pollution in Dushanbe. High ratios of levoglucosan to mannosan, and syringic acid to vanillic acid suggest that mixed hardwood and herbaceous plants were the main burning materials in the area, with softwood being a minor one. According to the diagnostic tracer ratio, OC derived from BB constituted a large fraction of the primary OC (POC) in ambient aerosols, accounting for an annual mean of nearly 30% and reaching 63% in winter. The annual contribution of fungal spores to POC was 10%, with a maximum of 16% in spring. Measurements of plant debris, accounting for 3% of POC, divulged that these have the same variation as fungal spores.

Synergistic conversion of CO2 into C1 and C2 gases using hybrid in-doped TiO2 and g-C3N4 photocatalysts

Achieving high-efficiency photocatalytic conversion of CO2 into value-added chemicals remains a challenge. This study synthesizes In-doped TiO2 and g-C3N4 composites (In-TiO2/g-C3N4) via a facile and reliable method. The as-synthesized In-TiO2/g-C3N4 produces CO, CH4, and C2H4 under UV, and CO and CH4 under visible light from gaseous CO2 and H2O vapor. A prolonged photocatalysis results in the continuous production of the same set of carbonaceous compounds over 30 h, with a photonic yield of ∼ 40%. The yield of C2H4 with In-TiO2/g-C3N4 is ∼ 11-times greater than the sum of In-TiO2 and g-C3N4. The CO2 adsorption isotherms show that In-TiO2 acts as a CO2 adsorbent and photocatalyst whereas g-C3N4 mainly works as a photocatalyst. In-situ FTIR study reveals the formation of CH4 and C2H4 on In-TiO2/g-C3N4. Time-resolved photoluminescence indicate that In-doping facilitates charge transfer and a strongly coupled g-C3N4 induces cascaded charge transfer. This leads to inhibited charge recombination and long-lived charge carriers.

Decoupling of inorganic and organic carbon during slab mantle devolatilisation

Serpentinites are an important sink for both inorganic and organic carbon, and their behavior during subduction is thought to play a fundamental role in the global cycling of carbon. Here we show that fluid-derived veins are preserved within the Zermatt-Saas ultra-high pressure serpentinites providing key evidence for carbonate mobility during serpentinite devolatilisation. We show through the O, C, and Sr isotope analyses of vein minerals and the host serpentinites that about 90% of the meta-serpentinite inorganic carbon is remobilized during slab devolatilisation. In contrast, graphite-like carbonaceous compounds remain trapped within the host rock as inclusions within metamorphic olivine while the bulk elemental and isotope composition of organic carbon remains relatively unchanged during the subduction process. This shows a decoupling behavior of carbon during serpentinite dehydration in subduction zones. This process will therefore facilitate the transfer of inorganic carbon to the mantle wedge and the preferential slab sequestration of organic carbon en route to the deep mantle.

Accuracy prediction using data-driven algorithm for carbon containing compounds

Technology is usually a solution to a problem and seeks materials with specific properties; therefore, materials are tailored to specific needs and serve a particular purpose. Therefore, careful research is needed to meet this growing demand for new materials. However, the conventional method of discovering materials has two key drawbacks: high cost and a lot of time. Materials research focuses on a more efficient side to address these obstacles. It is currently looking for data-driven, highly computational approaches with maximum accuracy to develop tailored materials in a short time. In recent years, work in this area has increased significantly, and some have made significant discoveries. Machine learning is an entirely data-driven technique that meets all these requirements equally. Various machine learning algorithms may be taught, and significant findings are produced from many computational and experimental data in materials science. In this work, datasets of carbonaceous compounds are used to predict the accuracy of data-driven machine learning algorithms. First, the optimal number of clusters is calculated using the elbow method. Then, the whole datasets are divided into four clusters. Afterward, the accuracy is predicted using the decision tree and random forest regression models for performance evaluation. It is found that the decision tree model achieves 99.4% accuracy compared to the random forest model (99.23%).

Associations of Carbonaceous Compounds and Water-Soluble Inorganic Ions in Ambient PM2.5 with Renal Function in Older Individuals: The China BAPE Study.

Exposure to fine particulate matter (PM2.5) is proven to be associated with a decline in renal function. However, few studies have explored the acute renal damage from carbonaceous compounds and water-soluble inorganic ions (WSIIs), which constitute the bulk of total PM2.5 mass. We examined the acute effect of these constituents of ambient PM2.5 on renal function in older Chinese individuals. Seventy-one healthy people aged 60-69 years from Jinan, China, were enrolled and visited monthly and asked to complete survey questionnaires, undergo physical exams, and provide blood samples. The hourly concentrations of organic carbon, elemental carbon (EC), and WSIIs in ambient PM2.5 were collected from a fixed-site monitoring station. The association between PM2.5 constituents and estimated glomerular filtration rate (eGFR) was evaluated using linear mixed-effects models after controlling for a series of covariates. We observed that ambient carbonaceous compounds and WSIIs were associated with a significant decline in renal function. The interquartile range increased in the 24 h moving average of carbonaceous compounds, and WSIIs in ambient PM2.5 were associated with -13.11% [95% confidence interval (95% CI): -19.49, -6.21%] to -0.81% (95% CI: -4.17, 2.67%) changes in eGFR. We found significant associations between EC, chlorine (Cl-), sodium (Na+), and magnesium (Mg2+) and eGFR in single-pollutant, constituent-PM2.5, and residual-constituent models with a lag period of 0-24 h. This study demonstrated that carbonaceous compounds and WSIIs in PM2.5 were inversely associated with renal function.

Putative fossil blood cells reinterpreted as diagenetic structures.

Red to red-orange spheres in the vascular canals of fossil bone thin sections have been repeatedly reported using light microscopy. Some of these have been interpreted as the fossilized remains of blood cells or, alternatively, pyrite framboids. Here, we assess claims of blood cell preservation within bones of the therizinosauroid theropod Beipiaosaurus inexpectus from the Jehol Lagerstätte. Using Raman spectroscopy, Energy Dispersive X-ray Spectrometry, and Time of Flight Secondary Ion Mass Spectroscopy, we found evidence of high taphonomic alteration of the bone. We also found that the vascular canals in the bone, once purported to contain fossil red blood cell, are filled with a mix of clay minerals and carbonaceous compounds. The spheres could not be analyzed in isolation, but we did not find any evidence of pyrite or heme compounds in the vessels, surrounding bone, or matrix. However, we did observe similar spheres under light microscopy in petrified wood found in proximity to the dinosaur. Consequently, we conclude that the red spheres are most likely diagenetic structures replicated by the clay minerals present throughout the vascular canals.

Online Chemical Characterization and Sources of Submicron Aerosol in the Major Mediterranean Port City of Piraeus, Greece

Port cities are affected by a wide array of emissions, including those from the shipping, road transport, and residential sectors; therefore, the characterization and apportionment of such sources in a high temporal resolution is crucial. This study presents measurements of fine aerosol chemical composition in Piraeus, one of the largest European ports, during two monthly periods (winter vs. summer) in 2018–2019, using online instrumentation (Aerosol Chemical Speciation Monitor—ACSM, 7-λ aethalometer). PMF source apportionment was performed on the ACSM mass spectra to quantify organic aerosol (OA) components, while equivalent black carbon (BC) was decomposed to its fossil fuel combustion and biomass burning (BB) fractions. The combined traffic, shipping and, especially, residential emissions led to considerably elevated submicron aerosol levels (22.8 μg m−3) in winter, which frequently became episodic late at night under stagnant conditions. Carbonaceous compounds comprised the major portion of this submicron aerosol in winter, with mean OA and BC contributions of 61% (13.9 μg m−3) and 16% (3.7 μg m−3), respectively. The contribution of BB to BC concentrations was considerable and spatially uniform. OA related to BB emissions (fresh and processed) and hydrocarbon-like OA (from vehicular traffic and port-related fossil fuel emissions including shipping) accounted for 37% and 30% of OA, respectively. In summer, the average PM1 concentration was significantly lower (14.8 μg m−3) and less variable, especially for the components associated with secondary aerosols (such as OA and sulfate). The effect of the port sector was evident in summer and maintained BC concentrations at high levels (2.8 μg m−3), despite the absence of BB and improved atmospheric dispersion. Oxygenated components yielded over 70% of OA in summer, with the more oxidized secondary component of regional origin being dominant (41%) despite the intensity of local sources, in the Piraeus environment. In general, with respect to local sources that can be the target of mitigation policies, this work highlights the importance of port-related activities but also reveals the extensive wintertime impact of residential wood burning. While a separation of the BB source is feasible, more research is needed on how to disentangle the short-term effects of different fossil-fuel combustion sources.

An overview of recent advances in sediment microbial fuel cells for wastewater treatment and energy production

In developing countries, the presence of wastewater is undesirable due to a costly investment for the treatment unit and energy-intensive for the operation. The wastewater treatment units in developing countries usually are not appropriately operated due to lacking operational cost. Therefore, it is not surprising if wastewater has never been considered a potential resource, even though it is rich in organics and nutrient substances. Biological treatment enables the conversion of wastewater into valuable products and energy. Sediment Microbial fuel cells (SMFCs) are emerging technologies envisaged as a feasible solution for simultaneous removal of carbonaceous compounds and generation of electricity. In SMFCs, power can be generated naturally by embedding an anode in the sediment and immersing the cathode in the water above the sediment. One of the most significant obstacles to upscaling and practical applications of the SMFCs appears to be the low-power output. The entire performance of an SMFC is determined by microorganisms, proper electrode materials, optimal SMFC designs, and process parameter optimization. This paper will discuss the recent progress of SMFC research related to its application in wastewater treatments and energy production. The advantages and obstacles of using SMFC in wastewater treatment are also presented.

Comparison of Carbonaceous Compounds Emission from the Co-Combustion of Coal and Waste in Boilers Used in Residential Heating in Poland, Central Europe

In this study, the effect of the addition of waste on the emissions from coal co-combustion was investigated. Coal was co-combusted with different additions of medium-density fiberboard and polyethylene terephthalate plastic (10 and 50%), in a low-power boiler (18 W). Polycyclic aromatic hydrocarbons, phenols, alkylphenols, phthalates, and biomass burning markers emissions were determined. Gas chromatography, coupled with a mass spectrometry detector, was used to analyze these compounds in particulate matter and gas phase, after extraction and derivatization. The emissions of polycyclic aromatic hydrocarbons were the highest among all the compounds determined. The total emission of these compounds was 215.1 mg/kg for coal, and 637.7 and 948.3 mg/kg for a 10 and 50% additive of polyethylene terephthalate plastic, respectively. For the 10 and 50% additive of medium-density fiberboard, the total emission was 474.2 and 464.0 mg/kg, respectively. The 50% addition of PET also had the highest emissions of phenols (638.5 mg/kg), alkylphenols (246.5 mg/kg), and phthalates (18.1 mg/kg), except for biomass burning markers, where the emissions were the highest for the 50% addition of medium-density fiberboard (541.3 mg/kg). In our opinion, the obtained results are insufficient for the identification of source apportionment from household heating.

Unusual width of the superconducting transition in a hydride.

The long-sought goal of room-temperature superconductivity has reportedly recently been realized in a carbonaceous sulfur hydride compound under high pressure, as reported by Snider et al. [1]. The evidence presented in that paper is stronger than in other similar recent reports of high temperature superconductivity in hydrides under high pressure [2-7], and has been received with universal acclaim [8-10]. Here we point out that features of the experimental data shown in Ref. [1] indicate that the phenomenon observed in that material is not superconductivity. This observation calls into question earlier similar claims of high temperature conventional superconductivity in hydrides under high pressure based on similar or weaker evidence [2-7].

Progress of the Catalytic Deactivation of H‐ZSM‐5 Zeolite in Glycerol Dehydration

AbstractGlycerol conversion into value‐added chemicals has received much attention due to the prospect of increasing the biodiesel industry‘s profitability. The dehydration of glycerol is one of the most explored reactions in the valorization of glycerol, and the zeolite H‐ZSM‐5 is one of the furthermost used structures. In this study, several characterization techniques were used to investigate the detailed aging of coke in spent H‐ZSM‐5 zeolites after their use in the gas‐phase glycerol dehydration to produce acrolein. The carbonaceous deposits formed almost totally in the first minutes of the reaction. They rapidly got trapped inside the pores, hampering the accessibility to active sites and the zeolite‘s full catalytic action. Two types of coke were formed during the reaction: polyglycols, on the external surface, and aromatics, inside the pores, representing the majority (∼98 wt.%) of the carbonaceous compounds. Besides, aromatic compounds age over time, becoming bulkier and more deficient in hydrogen. We also found a correlation between the amount of coke, its size, accessibility to the acid active sites, and changes in crystallographic parameters of the zeolite with the presence of coke.

Seasonal changes in stable carbon isotopic composition in the bulk aerosol and gas phases at a suburban site in Prague

Isotope fractionation between the gas and aerosol phases is an important phenomenon for studying atmospheric processes. Here, for the first time, seasonally resolved stable carbon isotope ratio (δ13C) values are systematically used to study phase interactions in bulk aerosol and gaseous carbonaceous samples. Seasonal variations in the δ13C of total carbon (TC; δ13CTC) and water-soluble organic carbon (WSOC; δ13CWSOC) in fine aerosol particles (PM2.5) as well as in the total carbon of part of the gas phase (TCgas; δ13CTCgas) were studied at a suburban site in Prague, Czech Republic, Central Europe. Year-round samples were collected for the main and backup filters from 14 April 2016 to 1 May 2017 every 6 days with a 48 h sampling period (n = 66). During all seasons, the highest 13C enrichment was found in WSOC, followed by particulate TC, whereas the highest 13C depletion was found in gaseous TC. We observed a clear seasonal pattern for all δ13C, with the highest values in winter (avg. δ13CTC = −25.5 ± 0.8‰, δ13CWSOC = −25.0 ± 0.7‰, δ13CTCgas = −27.7 ± 0.5‰) and the lowest values in summer (avg. δ13CTC = −27.2 ± 0.5‰, δ13CWSOC = −26.4 ± 0.3‰, δ13CTCgas = −28.9 ± 0.3‰). This study supports the existence of different aerosol sources at the site during the year. Despite the different seasonal compositions of carbonaceous aerosols, the isotope difference (Δδ13C) between δ13CTC (aerosol) and δ13CTCgas (gas phase) was similar during the seasons (year avg. 1.97 ± 0.50‰). Moreover, Δδ13C between WSOC and TC in PM2.5 showed a difference between spring and winter, but in general, these values were also similar year-round (year avg. 0.71 ± 0.37‰). During the entire period, TCgas and WSOC were the most 13C-depleted and most 13C-enriched fractions, respectively, and although the resulting difference Δ(δ13CWSOC − δ13CTCgas) was significant, it was almost invariant throughout the year (2.67 ± 0.44‰). The present study suggests that the stable carbon isotopic fractionation between the bulk aerosol and gas phases is probably not entirely dependent on the chemical composition of individual carbonaceous compounds from different sources.