Aromatic Fractions Research Articles

Investigation on the oxidation aging resistance of asphalt by rejuvenator-loaded porous CaCO3 microparticles

ABSTRACT To delay asphalt binder oxidation-aging, a slow-release strategy was proposed, wherein porous CaCO3 microparticles act as a sustained-release carrier. Porous CaCO3 microparticles act as rejuvenators to supplement the evaporated saturate and aromatic fractions during the asphalt pavements service life. Porous CaCO3 microparticles were designed and synthesised via a double-decomposition method, and a vacuum-assisted method was applied to load the rejuvenator into the nanopores. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and laser particle size analysis indicated the successful synthesis of porous CaCO3 microparticles and the realisation of loading for the rejuvenator. Furthermore, CaCO3 microparticles were added as alternatives to mineral fillers in the neat asphalt binder, and short – and long-term aging was conducted on the asphalt mastic. The aging resistance performance results suggested that the CaCO3 microparticles loaded with the rejuvenator exhibited good slow-release behaviour after 20 and 40 h of pressure vessel aging when the dose of the microparticles reached 30%–50%. In addition, the rejuvenator release mechanism investigated by molecular dynamics (MD) simulations demonstrated that the rejuvenator's diffusion coefficient in the aging asphalt system reached 32.9 × 10−7 cm2/s, an increase of about 24% compared to that of the unaged asphalt system and the binding energy of the asphalt rejuvenator after aging was 7.1 times the binding energy of the nanopore rejuvenator. This study indicates that rejuvenator-loaded porous CaCO3 microparticles are promising sustainable candidates for delaying oxidative aging in the asphalt pavement industry.

Effect of Sulfur Contents on Polycyclic Aromatic Compounds in Low-Rank Bituminous Coals

Different coal seams go through distinct biological, physical, and chemical processes. Polycyclic aromatic compounds (PACs) in coal may retain information about these processes, especially in low-rank bituminous coals. Three coal seams with different sulfur contents from the Ningwu Coalfield were studied to understand the relation of different sulfur contents with PAC formation in low-rank bituminous coals. Coal samples were extracted by solvent and separated using liquid chromatography. The collected aromatic hydrocarbon fractions were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). A total of 27 sulfur-containing PACs (SPACs) were identified in the high-sulfur samples, whereas only 8 SPACs were found in the low-sulfur coal and middle-sulfur coal. The total SPACs to total PACs ratios (T-SPACs/T-PACs) are 1.15%, 2.17%, and 10.65% in the low-sulfur, middle-sulfur, and high-sulfur coal, respectively. The variations of SPAC species and their content ratios indicate that SPAC formation is controlled by the sulfur contents in the low-rank bituminous coals. A total of 18 oxygen-containing PACs (OPACs) were identified in the low-sulfur coal and middle-sulfur coal, whereas only 11 OPACs were found in the high-sulfur samples. The average ratios of OPACs to the identified aromatic compounds (T-OPACs/T-PACs) are 9.81%, 9.62%, and 6.91% in the low-, middle-, and high-sulfur coals, exhibiting a negative correlation with sulfur contents and indicating that OPACs were also influenced by sulfur contents in low-rank bituminous coals. The ratios of total contents of polycyclic aromatic hydrocarbons (PAHs) to total PACs (T-PAHs/T-PACs) are 89.1%, 88.2%, and 82.0% in the low-, middle-, and high-sulfur coals, respectively, indicating a decreasing trend from low- and middle-sulfur coal to high-sulfur coal. This variation could be caused by the reaction of PAHs and sulfur to form SPACs.

Bioremediation of petroleum-contaminated soil based on both toxicity risk control and hydrocarbon removal-progress and prospect.

Petroleum contamination remains a worldwide issue requiring cost-effective bioremediation techniques. However, establishing a universal bioremediation strategy for all types of oil-polluted sites is challenging. This difficulty arises from the heterogeneity of soil textures, the complexity of oil products, and the variations in local climate and environment across different oil-contaminated regions. Several factors can impede bioremediation efficacy: (i) differences in bioavailability and biodegradability between aliphatic and aromatic fractions of crude oil; (ii) inconsistencies between hydrocarbon removal efficiency and toxicity attenuation during remediation; (iii) varying adverse effect of aliphatic and aromatic fractions on soil microorganisms. This review examines the ecotoxicity risk of petroleum contamination to soil fauna and flora. It also discusses three primary bioremediation strategies: biostimulation with nutrients, bioaugmentation with petroleum degraders, and phytoremediation with plants. Based on current research and state-of-the-art challenges, we highlighted future research scopes should focus on (i) exploring the ecotoxicity differentiation of aliphatic and aromatic fractions of crude oil, (ii) establishing unified risk factors and indicators for evaluating oil pollution toxicity, (iii) determining the fate and transformation of aliphatic and aromatic fractions of crude oil using advanced analytical techniques, and (iv) developing combined bioremediation techniques that improve petroleum removal and ecotoxicity attenuation.

Geochemical evidences linking the Lower Cretaceous source rocks to the biodegraded bitumen seeps and tar sands in the Gulf of Guinea Basin

The source of biodegraded bitumen seeps and tar sands in the Nigerian axis of the Gulf of Guinea province has been a contentious issue for decades. The most prevalent opinion is that the biodegraded bitumen seeps are migration oils that were degraded by bacterial. In the present study, outcrop source rocks (Lower Cretaceous), core samples (Upper Cretaceous) from a shallow well-x, and bitumen seeps and tar sands from the eastern axis of the Dahomey Basin of Nigeria were analyzed. Rock-Eval™ pyrolysis show that the outcrop rocks are classified as having excellent-very good source quality; in contrast, those from well-x are classified as having only poor-fair quality. The cross plot of hydrogen index (HI) against Tmax indicates that samples from the outcrops contain type II/III organic matter, whereas well samples contain type III organic matter and all source rocks are thermally immature, which is supported by vitrinite reflectance (Ro: 0.20–0.48 %), and biomarker maturity parameters (C32 (S/S + R), MPI-I). In the bitumen seeps and tar sands, isoprenoids, n-alkanes, steranes and hopanes have been degraded, and tricyclic and tetracyclic terpanes are still mostly intact. In addition, C30 hopane and homohopanes have been demethylated, and C25 norhopanes are present in abundance, suggesting that the bitumen seeps and tar sands experienced heavy biodegradation in the range of PM-6 or greater. The distribution of 4,9-DMD, 4,8-DMD and 3,4-DMD diamondoids and the δ13C of saturate and aromatic fractions indicate that the bitumen seeps and tar sands were generated from Types II and III source rocks. The ratio of demethylated Ts/Tm indicates that the samples are low maturity and were generated from immature source rocks. Cross plots of tricyclic terpane ratios (C25/C26TT vs C25TT/C24TeT, C23/C21TT vs (C19+20)/C23TT, and C24TeT/C24TeT + C26TT vs (C19+20)/C23TT) also reveal that the biodegraded bitumen seeps and tar sands are closely related to source rocks in outcrop groups 1 and 2. This conclusion is supported by the ternary plots of tricyclic terpanes, 4,9DMD, 4,8DMD and 3,4DMD diamondoids, and the cross plot of EAI against DMDI-1. The occurrence of exsudatinite in the outcrop source rocks in group 1, consistent with early hydrocarbon generation, and the low ratio of demethylated Ts/Tm (<1) in the bitumen samples confirms that the biodegraded bitumen seeps and tar sands in the Nigerian Dahomey Basin were generated by the Lower Cretaceous source rocks in group 1. The study advances on the previous propositions on the source of bitumen seeps and tar sands and contributes our knowledge in the Gulf of Guinea Basin.

Analysis of Aromatic Fraction of Sparkling Wine Manufactured by Second Fermentation and Aging in Bottles Using Different Types of Closures

Analysis of Aromatic Fraction of Sparkling Wine Manufactured by Second Fermentation and Aging in Bottles Using Different Types of Closures

Study of cork from Quercus suber L. with and without yellow spot: aromatic fraction and cellular structure

Study of cork from Quercus suber L. with and without yellow spot: aromatic fraction and cellular structure

Chemical characterization of bitumen-derived pyrolysis oil

The objective of this study is to characterize the elemental and functional group analysis of oils obtained from the pyrolysis of oil sand bitumen with the aim of determining oil quality. For this purpose, the present study extracted bitumen from oil sand using toluene, thermally cracked the bitumen using a fixed bed reactor, chromatographically separated the derived oil into saturate and aromatic fractions, and employed Energy dispersive x-ray fluorescence and Fourier transform-infrared spectroscopy to characterize them. The results of the elemental analysis indicated that potassium had the highest mean concentration of about 531 mg/L and 552 mg/L in the saturate and aromatic fractions respectively. The mean elemental concentrations of the aromatic fraction were relatively higher than the saturate fraction. The functional group analysis showed the predominant presence of C-H (CH3) and C-H (CH2) groups, indicating the presence of aliphatic compounds in the pyrolytic oils, in addition to the presence of sulfur reflected by the sulphoxide index. The findings of the study provide valuable information on the feedstock potential of the pyrolysis oil in the petrochemical industry. This study provides baseline information required for exploitation of the heavy oil resource which is yet to be commercially mined in Nigeria.

Structural Characteristics of the Yunnan Deashed Lignite and Construction of the Macromolecular Structure Model.

The structural characteristics and macromolecular model of lignite are important for its effective utilization. In this paper, Yunnan (YN) lignite was taken as the study object, and deashing pretreatment was carried out to remove the influence of minerals in lignite before spectroscopic analysis. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and 13C nuclear magnetic resonance (NMR) spectroscopy of deashed lignite and gas chromatography and mass spectrometry (GC/MS) of methanol lignite extract were subsequently performed. Then, the lignite structural parameters were calculated, and lignite macromolecular models were constructed and optimized. The results showed that the aromatic carbon ratio and molar fraction of aromatics in YN lignite were 0.62 and 0.19, respectively. The numbers of benzene, naphthalene, phenanthrene, pyrrole and pyridine groups were calculated as 4, 4, 1, 1, and 4, respectively. Afterward, 2D and 3D macromolecular structure models of YN lignite were drawn and optimized by ChemDraw software, and the chemical shift regions of the predicted 13C NMR spectrum agreed well with the experimental spectrum, suggesting the reliability of the constructed macromolecular structure model of YN lignite.

Acetaminophen removal by peroxymonosulfate catalyzed by C and O co-doped graphitic carbon nitride in synthetic secondary treatment effluent matrix

Catalytic oxidation using carbonaceous materials and peroxymonosulfate (PMS) has attracted attention because of high potential in pharmaceuticals removal. For successful field applications, it is essential to identify the components and characteristics in real water matrices affecting the performance, though it has hardly been elaborated. Therefore, acetaminophen (ACT) removal by C and O co-doped graphitic carbon nitride (COCN) and PMS was investigated in synthetic secondary treatment effluent (SSTE) and compared to that in deionized water (DIW). ACT removal was significantly suppressed in SSTE (20.33 %) compared to that in DIW (94.20 %) under 10 mg/L ACT, 100 mg/L COCN, and 0.5 mM PMS. However, it was enhanced greatly with increasing COCN and/or PMS dose. The reactive species were the same in SSTE and DIW, of which 1O2 from O2− dominantly contributed. However, the amount of them was considerably lower in SSTE than in DIW. ACT removal was slightly affected by the anions in SSTE, such as Cl−, SO42−, and NO3−, at 1.41 × 10−3–0.71 mM. But it was suppressed greatly by 0.71 mM phosphates and by 10 mg/L humic acid and natural organic matter, via consuming hydrophobic and aromatic fractions. It is strongly suggested that the reactivity of COCN/PMS in SSTE was dominantly affected by raised pH and scavenging O2− reducing DOM, which decreased 1O2 generation. The results would significantly contribute to successful practical applications of catalytic systems.

Kinetic insights and pollution mitigation in waste tire pyrolysis: Targeting sulfur, nitrogen, and PAHs emissions

Waste tires have potential to be used for generation of fuel via thermal degradation because of their non-biodegradable nature. Nevertheless, the formation of various pollutants such as sulfur-based and nitrogen-based are inevitable due to presence of nitrogen and sulfur containing compounds during waste tires production. The main purpose was to examine the effect of variating heating rates on pollutants release because heating rate is an important parameter which influences the pollutants releasing profile. Moreover, Ar and CO2 as reaction medium were used to identify their behavior for restraining the PAHs in gas phase. The present study investigates the influence of heating rates and carrier gas environment (Argon and CO2) to reduce the pollutants emission. Thermogravimetry-Mass Spectrum coupled with Fourier transform infrared spectrometer was used to evaluate the thermal degradation and pollutants formation. The major degradation of waste tires occurred between 300 and 500 ℃. The sulfur-based (H2S, CS2, COS, SO2, and CH3SH), nitrogen-based (NH3, HNCO, NO, and HCN) and 9 series of PAHs pollutants were detected. The higher heating rates promoted the pollutants emission. The degradation of compounds having sulfur content formed -SH radials and -SH helped in further release of sulfur based-pollutants. The NH3 releasing profile started after 200 ℃ and released till around 800 ℃ for 30 ⁰C/min and 40 ⁰C/min but its emission was very low after 600 ⁰C for heating rates 5 ⁰C/min, 10 ⁰C/min, and 20 ⁰C/min. The aromatic compounds fraction was more at higher heating rate due to short residence time for pyrolytic products to go through secondary reaction. The 5 ℃/min and 10 ℃/min were considered favorable heating rates in terms of achieving lowest activation energy in both gas environments. The thermodynamic parameters analysis suggested that waste tires pyrolysis was non-spontaneous and endothermic reaction as well as feedstocks showed potential to be utilized for waste conversion.

Impact of deodorisation time and temperature on the removal of different MOAH structures: a lab-scale study on spiked coconut oil

Vegetable fats and oils are prone to contamination by mineral oil hydrocarbons due to the lipophilic and ubiquitous character of the latter. As the aromatic fraction of these hydrocarbons, MOAH, is associated with carcinogenicity, mutagenicity, and detrimental effects on foetal development, finding strategies to limit or reduce their contamination is highly relevant. Deodorisation (i.e. a refining step) has shown the ability to remove MOAH < C25 in vegetable fats and oils, but there is little information about the structures removed. Therefore, the present study investigated the impact of deodorisation conditions on the removal of different structures of MOAH in spiked coconut oil. An inscribed central composite design was built with time and temperature as variables (0.5-4h, 150-240 °C), while pressure (3 mbar) and steam flow (1 g water/g oil per hour) were kept constant. The analysis of MOAH in the oil was performed using a fully automated liquid chromatography coupled with two parallel comprehensive two-dimensional gas chromatography systems with flame ionisation and time-of-flight mass spectrometric detection. Response surfaces plotting the MOAH loss according to time and temperature were built for different MOAH fractions. The latter were defined based on the number of aromatic rings (>3 or ≤3) and the number of carbon atoms present (C16-C20, C20-C24, C24-C35, C35-C40). It was found that at 200 °C, compounds < C24, including weakly alkylated triaromatics, could be reduced to below the limit of quantification, while at 230 °C, it was possible to remove >60% of the C24-C35 fraction, including pentaromatics of low alkylation.

Thermal steam treatment effect of metallic sodium nanoparticles for high-carbon, low permeability Domanic rocks

In a study aimed at exploring novel methods for enhancing hydrocarbon extraction from shale reservoirs, we conducted an experimental study to model the effects of thermal steam treatment on high-carbon, low-permeability Domanic shale in the presence of sodium metal nanoparticles. We characterized the mineral composition of the rock samples and evaluated the yield and quality of extracted hydrocarbons before and after treatment. Our results demonstrated an increase in extract yield with increasing treatment temperature. Notably, we observed a significantly augmented effect when we introduced sodium nanoparticles into the reaction system, enabling a 100 °C reduction in treatment temperature while maintaining comparable capabilities for extracting organic matter. It was found that the experimental products exhibited enrichment in saturated hydrocarbons, coupled with a decrease in resinous-asphaltenic substances. Within the saturated fraction, we observed a shift towards lighter alkanes and cycloalkanes (C12–C14). Moreover, it has been found that the highest yield of low molecular weight liquid hydrocarbons is acheived in the experiment involving sodium nanoparticles at 250 °C. Upon further increasing the temperature to 300 °C, we noted a decline in liquid hydrocarbon content, accompanied by an increase in gaseous hydrocarbons (C1–C4). Besides, thermal steam treatment substantially reduced the proportion of sulfur-containing aromatic compounds, such as alkylbenzothiophenes, dibenzo- and naphthothiophenes, in the aromatic fraction. The addition of sodium nanoparticles facilitated near-complete desulfurization of this fraction. Moreover, we observed a significant reduction in the total sulfur content of the extracted organic matter. Hydrothermal treatment in the presence of nanoparticles induced transformations in the kerogen structure and structural and phase changes in the mineral components of the shale.

Evaluation of the Behavior of Two Tricyclic-Fused Host Systems in the Presence of Single and Mixed Isomers of the C8H10 Aromatic Crude Oil Fraction

Evaluation of the Behavior of Two Tricyclic-Fused Host Systems in the Presence of Single and Mixed Isomers of the C₈H₁₀ Aromatic Crude Oil Fraction

Seasonal studies of aquatic humic substances from Amazon rivers: characterization and interaction with Cu (II), Fe (II), and Al (III) using EEM-PARAFAC and 2D FTIR correlation analyses.

Aquatic humic substances (AHS) are defined asan important components of organic matter, being composed as small molecules in a supramolecular structure and can interact with metallic ions, thereby altering the bioavailability of these species. To better understand this behavior, AHS were extracted and characterized from Negro River, located near Manaus city and Carú River, that is situated in Itacoatiara city, an area experiencing increasing anthropogenic actions; both were characterized as blackwater rivers. The AHS were characterized by 13C nuclear magnetic ressonance and thermochemolysis GC-MS to obtain structural characteristics. Interaction studies with Cu (II), Al (III), and Fe (III) were investigated using fluorescence spectroscopy applied to parallel factor analysis (PARAFAC) and two-dimensional correlation spectroscopy with Fourier transform infrared spectroscopy (2D-COS FTIR). The AHS from dry season had more aromatic fractions not derived from lignin and had higher content of alkyls moities from microbial sources and vegetal tissues of autochthonous origin, while AHS isolated in the rainy season showed more metals in its molecular architecture, lignin units, and polysacharide structures. The study showed that AHS composition from rainy season were able to interact with Al (III), Fe (III), and Cu (II). Two fluorescent components were identified as responsible for interaction: C1 (blue-shifted) and C2 (red-shifted). C1 showed higher complexation capacities but with lower complexation stability constants (KML ranged from 0.3 to 7.9 × 105) than C2 (KML ranged from 3.1 to 10.0 × 105). 2D-COS FTIR showed that the COO- and C-O in phenolic were the most important functional groups for interaction with studied metallic ions.

Biological origin and depositional environment of crude oils in the Qiongdongnan Basin: Insights from molecular biomarkers and whole oil carbon isotope

Molecular biomarker and whole oil carbon isotope (δ13Coil) analyses were conducted on eleven typical crude oils from the Qiongdongnan Basin to investigate their biological sources and depositional environments. Saturated hydrocarbon biomarkers in most samples are characterized by angiosperm-derived compounds, with aromatic compounds dominated by the naphthalene, phenanthrene, biphenyl, and fluorene series. The related source rocks of these oils were mainly deposited under oxic condition, but a subanoxic–suboxic and enclosed water column condition in the Central Depression during Oligocene. The identification of simonellite and related compounds in the aromatic fractions provides reliable evidence for the input of coniferous gymnosperms. Cadalene may also have a potential association with gymnosperms since it shows a strong positive correlation with simonellite. Evidence from density, n-alkanes, short-chain alkylbenzenes and secondary brine inclusions indicates that the unique crude oil B13–1 may have suffered from thermal alteration. These crude oils (excluding B13-1) can be classified into four types based on the δ13Coil values and molecular biomarkers. Type A oil (solely S34-3) is characterized by non-angiosperm plants, with minor dinoflagellates and increasing contribution from conifer gymnosperms than others. Type B oils (L17–2, L18–1, L25-1, and L25-1W) show heavy δ13Coil (−24 ‰ to −25 ‰) and mixed contributions from both angiosperms and marine algae, with the marine algae contribution increasing. Type C oils (L13–2 and B21-1) share similar biological sources with Type B, but the moderately δ13Coil (−25‰ to −26‰) and high level of terrestrial biomarkers suggesting a predominant contribution of angiosperms. Type D oils (sample Y13-1a, Y13-1b, and Y13-4) possess the lightest δ13Coil (mainly below −26‰) and are primarily derived from angiosperms, with mangrove vegetation playing an important role. Spearman correlation analysis among 14 source biomarker parameters with δ13Coil and geological setting of related source rocks implied that the marine algae should be responsible for the heavy δ13Coil in the Type B. The contribution of marine algae in the Central Depression may have been neglected in the past, as it is usually covered by remarkable angiosperm biomarkers.

Comparison of water-soluble and water-insoluble organic compositions attributing to different light absorption efficiency between residential coal and biomass burning emissions

Abstract. There are growing concerns about the climate impacts of absorbing organic carbon (also known as brown carbon, BrC) in the environment, yet its chemical composition and association with the light absorption capabilities remain poorly understood. This study characterized water-soluble and water-insoluble organic carbon (WSOC and WIOC) from residential solid fuel combustion at the molecular level and evaluated their quantitative relationship with mass absorption efficiency (MAE). The MAE values at λ = 365 nm from biomass burning were significantly higher than those from coal combustion (p &lt; 0.05). Thousands of peaks were identified in the m/z range of 150–800, with the most intense ion peaks occurring between m/z 200–500 for WSOC and m/z 600–800 for WIOC, respectively. The CHO group predominated in the WSOC extract from biomass burning emissions, while sulfur-containing compounds (SOCs) including CHOS and CHONS were more intense in the WIOC extract, particularly from coal emissions. Emissions of the CHON group were positively correlated with the fuel nitrogen content (r = 0.936; p &lt; 0.05), explaining their higher abundance in coal emissions compared to biomass. The SOC emissions were more predominant during flaming phases, as indicated by a positive correlation with modified combustion efficiency (MCE) (r = 0.750; p &lt; 0.05). The unique formulas of coal combustion aerosols were in the lower H/C and O/C regions, with higher unsaturated compounds in the van Krevelen (VK) diagram. In the WIOC extract, coal combustion emissions contained significantly higher fractions of condensed aromatics (32 %–59 %) compared to only 4.3 %–9.7 % in biomass burning emissions. In contrast, the CHOS group in biomass burning emissions was characterized by larger condensed aromatic compound fractions than those in coal combustion. Moreover, the CHOS aromatic compound fractions were positively correlated with MAE values in both WSOC (r = 0.714; p &lt; 0.05) and WIOC extracts (r = 0.929; p &lt; 0.001), suggesting that these compounds significantly contributed to MAE variabilities across different fuels.

Exploring the potential of Canavalia ensiformis for phytoremediation of B10 biodiesel-contaminated soil: insights on aromatic compound degradation and soil fertility

The widespread use of petroleum-based fuels poses a significant environmental problem due to the risks associated with accidental spills. Among the treatments available, phytoremediation is increasingly accepted as an effective and low-cost solution. This study aimed to evaluate the degradation of the aromatic fraction of biodiesel B10 and the soil fertility analysis in artificially contaminated soils treated with phytoremediation. The experimental design consisted of a 3x3 factorial, with three types of soil treatment: control, autoclaved, and planted with C. ensiformis L, and three levels of B10 biodiesel contamination: 0, 1, and 2%, to simulate spills of 30,000 and 60,000 L ha−1. The soil was analyzed at three depths: 0–10, 10–20, and 20–30 cm. The results indicated that aromatic compound degradation after phytoremediation was superior to 92,76% and 88,65% for 1% and 2% B10 soil contamination, respectively. The fuel contamination affected soil fertility, reducing the availability of phosphorus and zinc while increasing the Total Organic Carbon (TOC), pH, and the availability of manganese and iron for plants.

Influence of acidity and alkalinity of water environment on water stability of asphalt mixture: Phase II-microscopic erosion mechanism

Acidity and alkalinity of water environments have been proven to influence the water stability of asphalt mixture. However, the relevant influencing mechanism still remains unclear. To fulfill this research gap, this study conducted a series of microscopic tests, aiming at unveiling the microscopic erosion mechanism of the water environment on the water stability of asphalt mixture for better moisture stability achieved. Specifically, the asphalt-aggregate interfacial transition zone (ITZ) samples were prepared by combining #70 asphalt with limestone and granite, respectively, which were then immersed in water solutions at 3 different pH levels (pH = 3.0, 7.0, and 11.0) for 7 days. The chemical composition and microstructure of the asphalt film on the surface of the ITZ samples pre and post-treatment were scrutinized using the Fourier Transform Infrared Spectroscopy (FTIR) and the Atomic Force Microscope (AFM), while the development of microcracks at the asphalt-aggregate interface were identified and traced utilizing the Scanning Electron Microscope (SEM). The test results indicate that after treatment with acidic and alkaline aqueous solutions, the asphalt film's surface is enriched with polar components such as asphaltenes, resins, and aromatic fractions. The migration of these polar components to the surface of the asphalt film reduces the adhesion between asphalt-aggregate, leading to the formation of microcracks at the asphalt-aggregate interface. The most severe crack development occurs in alkaline water environment, followed by acidic water environment. It is interestingly noted that the adhesion at the asphalt-granite interface is improved under the acidic environment. This improvement may be attributed to the covalent nature of silica, which hinders the adsorption of ions from acidic solution into the asphalt film. This hindrance effectively prevents water intrusion at the asphalt-aggregate interface, thereby reducing the adhesion loss. These findings can help elucidate the mechanism of water damage in asphalt pavement exposed to real-world conditions and enhance its water stability with effective countermeasures proposed.

Quantification and isotopic characterization of benzene polycarboxylic acids (BPCA)-derived black carbon in deep oceanic sediments: Towards assessing pyrogenic inputs from marine sources

Methodologies based on benzene polycarboxylic acids (BPCA) selectively target the polymeric aromatic fraction of black carbon (BC) and are considered adequate to quantify pyrogenic inputs in environmental samples such as soils, lakes, and marine dissolved organic carbon. However, the usefulness of these methodologies to quantify BPCA-derived BC in deep-sea sediments has not been fully evaluated. In this manuscript we describe and validate a procedure to quantify BPCAs in deep oceanic sediments with very low organic carbon content. The resulting analytical procedure has produced reproducible quantitative data for BPCAs over a period of 10 months (coefficient of variation, CV = 6.4 − 6.6%). The stable carbon isotopes (δ13C) of BC_BPCA have been characterized using an LC Isolink™-irMS system with an accuracy better than 0.5‰. The quantitative and isotopic composition of several marine sediments has been characterized to investigate the relative contributions of marine/diagenetic and continental/pyrogenic sources to the BC accumulated in oceanic sediments from different contexts, ranging from upwelling systems to remote oceanic locations. Overall, a significant fraction of the sedimentary BC is of marine origin and should be considered in inventories of pyrogenic materials accumulated in the world oceans. However, the continental/pyrogenic sources can be largely dominant in marine settings with large inputs of pyrogenic materials.

Effect of oxidation kinetic aging on the adhesion behaviour of asphalt-aggregate interfaces from molecular view

ABSTRACT Asphalt oxidation kinetic aging effect on the adhesion behavior of asphalt-aggregate interfaces at atomistic scale was investigated in this study. The asphalts were aged at different aging durations. The sulfoxide and carbonyl functional group content as well as SARA fractions of the asphalts at different aging times were studied through the tests of Fourier Transform Infrared Spectroscopy (FTIR) and Saturate, Aromatic, Resin and Asphaltene (SARA) fractions. Asphalt molecular models of virgin, rapid-rate aged, slow-rate aged and full-aged were established based on SARA fractions and FTIR results, to construct asphalt quartz and asphalt-calcite interface systems at different aging stages. The simulation results showed that the nanostructure of asphalt is influenced by the aggregate type and asphalt oxidative aging. The growth rates of adhesion energy of asphalt-quartz and asphalt-calcite systems increase rapidly first and then slowly with aging time, but the growth rates are different. Meanwhile, the Van der Waals energy is the major energy source of adhesion energy, and the contribution of van der Waals and electrostatic energy to adhesion energy is different. The aging of asphaltene and resin promotes the adhesion ability to quartz or calcite, while the aging of aromatic components is not conducive and the saturate has almost no effect.