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1.
Environ Int ; 158: 106990, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34991251

RESUMO

INTRODUCTION: Epidemiological evidence suggests that motorized vehicle users have a higher air pollutant exposure (especially from vehicle exhaust) than active (walking or cycling) transport users. However, studies often relied on insufficiently diverse sample and ignored that minute ventilation has an effect on individuals' inhaled dose. This study examined commuters' breathing zone concentration and inhaled doses of black carbon (BC) when travelling by different transport modes in the Grand Paris region. METHODS: Personal exposure to BC was continuously measured with MicroAethalometer (MicroAeth AE51) portable monitors strapped on participants' shoulder with tube inlet at the level of the neck (breathing zone), and inhaled doses were derived from several methods estimating ventilation [based on metabolic equivalents from accelerometry [METs], heart rate, and breathing rate]. Trip stages and transport modes were assessed from GPS and mobility survey data. Breathing zone concentrations and inhaled doses of BC were compared across transport modes at the trip stage level (n = 7495 for 283 participants) using linear mixed effect models with a random intercept at individual level. RESULTS: Trip stages involving public transport and private motorized transport were associated with a 2.20 µg/m3 (95% CI: 1.99, 2.41) and 2.29 µg/m3 (95% CI: 2.10, 2.48) higher breathing zone concentration to BC than walking, respectively. Trip stages with other active modes had a 0.41 µg (95% CI: 0.25, 0.57) higher inhaled dose, while those involving public transport and private motorized transport had a 0.25 µg (95% CI: -0.35, -0.15) and 0.19 µg (95 %CI: -0.28, -0.10) lower inhaled dose of BC per 30 min than walking. CONCLUSION: The ranking of transport modes in terms of personal exposure was markedly different when breathing zone concentrations and inhaled doses were considered. Future studies should take both into account to explore the relationship of air pollutants in transport microenvironments with physiological response.


Assuntos
Poluentes Atmosféricos , Exposição Ambiental , Poluentes Atmosféricos/análise , Carbono , Exposição Ambiental/análise , Monitoramento Ambiental , Humanos , Exposição por Inalação , Material Particulado/análise , Fuligem/análise , Emissões de Veículos/análise
2.
Sci Total Environ ; 807(Pt 1): 150790, 2022 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-34624281

RESUMO

The vertical distribution of atmospheric aerosols plays an essential role in aerosol-radiation and aerosol-cloud interactions. Because of strong light absorption, the radiative effects of black carbon (BC) are highly sensitive to its vertical distribution; the lack of high-resolution observations is the reason for their poor quantification. We used a tethered balloon platform to acquire high-resolution vertical profiles of BC, particle number concentration, and meteorological parameters in the semi-arid region of Northwest China in December 2018. A total of 112 BC profiles were classified into four vertical distribution categories, which were determined by local emissions, regional transport, vertical mixing due to the ABL evolution, and topography. BC profiles with peaks near or above the atmospheric boundary layer (ABL) accounted for 57% of the profiles. Vertical single scattering albedo (SSA) profiles were subsequently calculated using the profiles of BC and particle size distribution. The vertical SSA distribution is generally modulated by BC profiles. The diurnal variations of the BC and SSA profiles were summarized using a boundary-layer normalization method. In the ABL, BC decreased and SSA increased with increasing height at 02:00, 08:00, and 20:00, while both BC and SSA exhibited a uniform distribution at 14:00. The SSA decreased above the ABL at 14:00, which might have had a profound impact on ABL development. These results provide a better understanding of the vertical BC and SSA distributions, which can also be used to reduce uncertainties in estimating the BC radiative effects.


Assuntos
Poluentes Atmosféricos , Aerossóis/análise , Poluentes Atmosféricos/análise , Carbono , Monitoramento Ambiental , Fuligem/análise
3.
Sci Total Environ ; 806(Pt 3): 151300, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34736751

RESUMO

Non-road construction equipment (NRCE) has become a vital contributor to urban air pollutants with the rapid urbanization in China. Black carbon (BC), as a key pollutant emitted from NRCE (mainly diesel-fueled), has attracted considerable concerns due to adverse impacts on climate change, visibility, and human health. However, the understanding of its emissions is still unclear based on limited research results. In this study, we conducted real-world measurements on BC emissions from 12 excavators and 9 loaders to characterize the variation and quantify fuel-based emission factors (EFs) by using a synchronous platform based on PEMS (SP-PEMS). We analyzed the impacts of key factors (operation mode, emission standard, and engine rated power) on BC emission comprehensively. High BC emission in working mode may be mainly owing to the increase of fuel consumption and the deterioration of air-fuel ratio. With more stringent emission standards, BC EFs of all tested NRCE present significant decreasing trends. Interestingly, NRCE with high rated power generally exhibits lower BC emissions. Through comparison, we find BC EFs in this study are generally higher than elemental carbon (EC) EFs reported in previous studies, which will lead BC emissions from NRCE to be underestimated while EC EFs are used instead of BC EFs. Furthermore, BC EFs of NRCE with Stage III are significantly higher (1-3 orders of magnitude) than those of on-road diesel trucks with the current mainstream emission standards of China IV and China V, which reinforces the urgency and importance of controlling BC emissions from NRCE in China. Finally, we recommend BC EFs of excavators and loaders under different emission standards and operation modes, and which preliminarily fills the gap in localized BC EFs of typical NRCE to relieve the urgent needs for emission inventory calculation.


Assuntos
Poluentes Atmosféricos , Emissões de Veículos , Poluentes Atmosféricos/análise , Carbono , China , Monitoramento Ambiental , Humanos , Fuligem/análise , Emissões de Veículos/análise
4.
Waste Manag ; 137: 110-120, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34752944

RESUMO

To promote the use of recycled waste materials as an industrial feedstock, this study examined the preparation of carbon black (CB) by partial oxidation of a spent tyre pyrolysis oil using a drop tube furnace. The effect of reaction temperature, the residence time of gas in the reactor and inlet gas oxygen concentration on the yield and properties of the CB were evaluated. The surface chemistry, chemical composition, morphological and thermal properties of the CB samples were characterised using XPS, EA, TEM, BET, and TGA, respectively. The CB yield increased with increasing reaction temperature but decreased as the residence time or oxygen concentration increases. The CB primarily consisted of C (90.5-98.6%) and O (0.9-7.4%), with small traces of S (<1%), Si (<1%) and H (<2%). Hydroxyl, carbonyl, and carboxyl are the key functional groups found on the CB surface, with the hydroxyl groups being dominant. The CB were highly graphitic with a lattice spacing in the range of 0.338-0.350 nm and had BET surface areas of 4-22 m2g-1. The mean primary particle size ranged from 92 to 176 nm and decreased with increasing reaction temperature and oxygen concentration. The CB aggregate configuration became more complex with increasing reaction temperature, residence time and oxygen concentration. The results were not only comparable with commercial CB products from fossil fuel feedstocks but are expected to provide the needed motivation to move towards circular economy strategies, which have positive impacts from a sustainability perspective.


Assuntos
Pirólise , Fuligem , Carbono , Temperatura , Resíduos
5.
Chemosphere ; 286(Pt 1): 131583, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34293558

RESUMO

Chemical degradation is one of the crucial methods for the remediation of hydrophobic organic compounds (HOCs) in soil/sediment. The sequestration effect of black carbon (BC) can affect the adsorption state of HOCs, thereby affecting their chemical degradability. Our study focused on the chemical degradability of 2-Chlorobiphenyl (PCB1) sequestrated on the typical BC (fly ash (FC), soot (SC), low-temperature biochar (BC400) and high-temperature biochar (BC900)) by iron-nickel bimetallic nanomaterials (nZVI/Ni) based on TENAX desorption technology. The results showed that PCB1 adsorbed in various states were simultaneously dechlorinated by nZVI/Ni. Specifically, rapid-desorption-state PCB1 tended to degrade more easily than resistant-desorption-state PCB1. Moreover, the degradation mechanism varied according to the type of BC. In the case of FC and SC, the degradation rate was lower than the desorption rate for the PCB1 in rapid and slow desorption states, and the degradation rate of PCB1 in the resistant desorption state was negligible. The PCB1 on FC and SC was first desorbed from BC and then degraded. However, in terms of BC400 and BC900, the degradation rate was higher than the desorption rate, and the degradation rate of the resistant-desorption-state PCB1 was 1.4 × 10-2 h-1 and 4.1 × 10-2 h-1, respectively. The graphitized structure of BC900 can directly transfer electrons, so more than 90% of the resistant-desorption-state PCB1 could be degraded. In addition, BC may affect the longevity of nZVI/Ni, thereby affecting its degradability. Therefore, the chemical degradability of BC-adsorbed HOCs should be comprehensively evaluated based on the adsorption state and the properties of BC.


Assuntos
Poluentes do Solo , Fuligem , Adsorção , Carvão Vegetal , Solo , Poluentes do Solo/análise , Tecnologia
6.
Chemosphere ; 286(Pt 1): 131520, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34298294

RESUMO

The remediation of oil spills and treatment of oily wastewater remains challenging to cope with nowadays. This has caused a surge in demand on adsorbent materials with multi-functionalities to effectively separate oils and nonpolar solvents from water. A superhydrophobic composite aerogel prepared from industrial waste-derived leached carbon black waste (LCBW) and polyvinyl alcohol (PVA) was developed in this work via conventional freeze-casting followed by surface coating. The composite aerogel was ultralight and porous with porosity >85% and tunable density ranging between 0.015 and 0.065 g/cm3. It was found that the embedded LCBW in the PVA network is crucial to impart superhydrophobicity and superoleophilicity to the aerogel as it enhances the surface roughness. Wettability test showed that composite aerogel prepared from 0.5 wt% PVA at PVA/LCBW ratio of 1 exhibited the highest water contact angle (156.7 ± 2.9°). LCBW also improved the thermal stability of the composite aerogel. With its superior selectivity, PVA/LCBW aerogel was used as selective adsorbent for a variety of oils and organic solvents. The adsorption test showed that the composite aerogel exhibited an adsorption capacity up to 35 times its original weight and could be reused repeatedly and easily recovered through a simple drying method.


Assuntos
Álcool de Polivinil , Água , Géis , Óleos , Óleos Vegetais , Fuligem , Molhabilidade
7.
J Environ Sci (China) ; 112: 218-230, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34955206

RESUMO

Aiming to investigate the impacts of n-octanol addition on the oxidation reactivity, morphology and graphitization of diesel exhaust particles, soot samples were collected from a four-cylinder turbocharged diesel engine fueled with D100 (neat diesel fuel), DO15 (85% diesel and 15% n-octanol, V/V) and DO30 (70% diesel and 30% n-octanol, V/V). All tests were conducted at two engine speeds of 1370 and 2150 r/min under a fixed torque of 125 N·m. The soot properties were characterized by thermogravimetric analyzer (TGA), transmission electron microscopy (TEM) and Raman spectroscopy (RS). The higher volatile organic fraction content, lower soot oxidation temperatures and lower activation energy from TGA results indicated that both the increasing n-octanol concentration and engine speed enhanced the soot oxidation reactivity. Additionally, quantitative analysis of TEM images showed that the soot derived from DO30 had the smallest primary particle diameters and fractal dimension, followed by those of soot produced by DO15 and D100. The RS results demonstrated that the n-octanol addition and higher engine speed led to a larger D1-FWHM (D1-full width at half maximum), AD1/AT (area ratio of D1 band and the total spectral) and AD3/AT (area ratio of D3 band and the total spectral) as well as a smaller La (crystallite width), revealing a lower degree of graphitization. Furthermore, the correlations between characterization parameters of soot properties and reactivity were nonlinear.


Assuntos
Gasolina , Fuligem , 1-Octanol , Gasolina/análise , Microscopia Eletrônica de Transmissão , Fuligem/análise , Emissões de Veículos/análise
8.
Sci Total Environ ; 806(Pt 2): 150570, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34582869

RESUMO

Brown carbon (BrC) can affect atmospheric radiation due to its strong absorption ability from the near ultraviolet to the visible range, thereby influencing global climate. However, given the complexity of BrC's chemical composition, its optical properties are still poorly understood, especially in mountainous areas. In this study, the black carbon (BC) tracer method is used to explore the light-absorbing properties of primary and secondary BrC at Mount Hua, China during the 2018 summer period. The primary BrC absorption contributes to 10-15% of the total BrC absorption at a wavelength of 370 nm. From the positive matrix factorization analysis, traffic emissions are found to be a major source of primary BrC absorption (44%), followed by industry and biomass-burning emissions (29%). The secondary BrC accounts for 87% of the total BrC absorption at a wavelength of 370 nm, indicating that BrC is dominated by secondary formation. The observation of a higher secondary BrC absorption diurnal pattern at Mount Hua can be affected by secondary BrC in the residual layer after sunrise and the formation of light-absorbing chromophores by photochemical oxidation in the afternoon. The estimated average mass absorption efficiencies of primary and secondary BrC (MAE_pri and MAE_sec, respectively) are 0.4 m2/g and 2.1 m2/g at wavelengths of 370 nm, respectively, indicating a stronger light-absorbing ability for secondary BrC than for primary BrC. There is no significant difference in MAE_pri within a daily variation, but the daytime MAE_sec value is higher than that during the night. Our study shows that secondary BrC is important to light absorption in mountainous areas.


Assuntos
Poluentes Atmosféricos , Carbono , Aerossóis/análise , Poluentes Atmosféricos/análise , Carbono/análise , Monitoramento Ambiental , Fuligem
9.
Chemosphere ; 286(Pt 2): 131712, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34333188

RESUMO

This work focuses on the thermally induced variation in the nanostructure, size of primary particles and oxidative reactivity of diesel soot and a commercial carbon black in an inert gas environment at temperatures ranging from 600 to 1000 °C. Soot nanostructure and size were characterized by high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The soot reactivity was evaluated with respect to activation energy (Ea) and characteristic oxidation temperature, including peak temperature (TP) and burnout temperature (Tb), using thermogravimetric analysis (TGA). The mass loss of diesel soot and carbon black rises when increasing the thermal treatment temperature, especially at 1000 °C, and a significant quantity of mass loss can be observed, which is primarily due to thermal fragmentation and the desorption of chemical species on soot surfaces. The HRTEM and XRD results all indicate that the thermally treated soot samples have more ordered nanostructure than the untreated samples. There is a reduction in the size of primary particles as thermal treatment temperature increases. The soot reactivity decreases after thermal treatment, as manifested by the elevation in Ea, TP, and Tb values. Moreover, the oxidation reactivity of soot samples is closely associated with the fringe length, tortuosity, and fringe tortuosity. Compared to carbon black, diesel soot with a more disorder structure has a higher oxidative reactivity.


Assuntos
Nanoestruturas , Fuligem , Microscopia Eletrônica de Transmissão , Oxirredução , Emissões de Veículos/análise
10.
J Environ Sci (China) ; 113: 104-117, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34963520

RESUMO

Ultrafine particles represent a growing concern in the public health community but their precise role in many illnesses is still unknown. This lack of knowledge is related to the experimental difficulty in linking their biological effects to their multiple properties, which are important determinants of toxicity. Our aim is to propose an interdisciplinary approach to study fine (FP) and ultrafine (UFP) particles, generated in a controlled manner using a miniCAST (Combustion Aerosol Standard) soot generator used with two different operating conditions (CAST1 and CAST3). The chemical characterization was performed by an untargeted analysis using ultra-high resolution mass spectrometry. In conjunction with this approach, subsequent analysis by gas chromatography-mass spectrometry (GC-MS) was performed to identify polycyclic aromatic hydrocarbons (PAH). CAST1 enabled the generation of FP with a predominance of small PAH molecules, and CAST3 enabled the generation of UFP, which presented higher numbers of carbon atoms corresponding to larger PAH molecules. Healthy normal human bronchial epithelial (NHBE) cells differentiated at the air-liquid interface (ALI) were directly exposed to these freshly emitted FP and UFP. Expression of MUC5AC, FOXJ1, OCLN and ZOI as well as microscopic observation confirmed the ciliated pseudostratified epithelial phenotype. Study of the mass deposition efficiency revealed a difference between the two operating conditions, probably due to the morphological differences between the two categories of particles. We demonstrated that only NHBE cells exposed to CAST3 particles induced upregulation in the gene expression of IL-8 and NQO1. This approach offers new perspectives to study FP and UFP with stable and controlled properties.


Assuntos
Poluentes Atmosféricos , Hidrocarbonetos Policíclicos Aromáticos , Aerossóis , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/toxicidade , Células Epiteliais/química , Humanos , Tamanho da Partícula , Material Particulado/análise , Material Particulado/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Fuligem
11.
Chemosphere ; 287(Pt 4): 132370, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34592209

RESUMO

The aim of this study is to produce an electrode that can be used in H2O2 production and Electro-Fenton (EF) process by an effective, cheap, and easy method. For this reason, a superhydrophobic electrode with a higher PTFE ratio and high thickness was produced with a simple press. The produced electrode was used in the production of H2O2 and mineralization of Atrazine. First, the effect of pH, cathode voltage, and operation time on H2O2 production was evaluated. The maximum H2O2 concentration (409 mg/L), the highest current efficiency (99.80%), and the lowest electrical energy consumption (3.16 kWh/kg) were obtained at 0.8 V, 7.0 of pH, and 120 min, and the stability of the electrode was evaluated up to 720 min. Then, the effects of the operational conditions (pH, cathode voltage, operating time, and catalyst concentration) in electro-Fenton were evaluated. The fastest degradation of Atrazine (>99%) was obtained at 2.0 V, 3.0 of pH, and 0.3 mM of Fe2+ in 15 min. In the final part of the study, the degradation intermediates were identified, and the characterization of the electrode was evaluated by SEM, XRD, FT-IR, tensiometer, potentiostat, and elemental analyzer.


Assuntos
Atrazina , Poluentes Químicos da Água , Carbono , Eletrodos , Peróxido de Hidrogênio , Oxirredução , Oxigênio , Fuligem , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
12.
Talanta ; 236: 122881, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635261

RESUMO

For the first time carbon black based electrode modified with paraffin was applied as a sensor on voltammetry of immobilized microparticles (VIMP) approach for determination of lead solid residues in hair dye samples. The solid microparticles of Pb(II) (Pb(CH3COO)2(s)) immobilized into the carbon paste sensor containing carbon black and paraffin were firstly reduced at initial potentials and further reoxidized at around -0.60 V during anodic scan. Electroanalytical parameters as well as supporting electrolyte composition, and pH were also evaluated. An analytical curve in 0.2 mol L-1 phosphate buffer solution (pH 5.0) from 0.04 to 3.2 µg (R2 = 0.999) with detection and quantification limits of 4 and 13 ng, respectively, were achieved. The method was applied to quantify lead solid residues in hair dye samples without previous mineralization or complex sample pre-treatment. Besides adequate repeatability, stability and selectivity of the developed sensor based on VIMP features, the method using carbon black based sensor was considered advantageous comparing to the results recorded by a spectrometric method (relative error lower than 8%) from several analytical viewpoints.


Assuntos
Fuligem , Eletrodos
13.
Talanta ; 237: 122869, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34736707

RESUMO

Point-of-care devices have attracted a huge interest by the scientific community because of the valuable potentiality for rapid diagnosis and precision medicine through cost-effective and easy-to-use devices for on-site measurement by unskilled personnel. Herein, we reported a smartphone-assisted electrochemical device consisted of a screen-printed electrode modified with carbon black nanomaterial and a commercially available smartphone potentiostat i.e. EmStat3 Blue, for sensitive detection of tyrosine. Once optimized the conditions, tyrosine was detected in standard solutions by square wave voltammetry, achieving a linear range comprised between 30 and 500 µM, with a detection limit equal to 4.4 µM. To detect tyrosine in serum, the interference of another amino acid i.e. tryptophan was hindered using a sample treatment with an extraction cartridge. The agreement of results analyzing serum samples with HPLC reference method and with the developed smart sensing system demonstrated the suitability of this smartphone-assisted sensing tool for cost-effective and rapid analyses of tyrosine in serum samples.


Assuntos
Técnicas Eletroquímicas , Smartphone , Eletrodos , Limite de Detecção , Fuligem , Tirosina
14.
J Hazard Mater ; 421: 126781, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34396976

RESUMO

The diversification of the production process and application of ultrafine carbon black (UFCB), one of the nanomaterials, make the difference in particle sizes that exposed to environment. Currently, few size-dependent toxicity studies of UFCB pay attention to targeted effects on detoxification organs. And there is a research gap in the size-dependent molecular toxicity of UFCB. Based on this, mouse hepatocytes and catalase (CAT) were used as targeted receptors for UFCB size-dependent cellular and molecular toxicity studies. Results indicate that UFCB13 nm induced higher ROS and lipid peroxidation levels. And the cell viability decreased to 22.5%, which is sharp contrast to UFCB50 nm (45.3%) and UFCB95 nm (55.1%). Mitochondrial dysfunction and a 25.2% early apoptosis rate are the further manifestation of the stronger cytotoxicity of UFCB13 nm. At the molecular level, the exposure of UFCB with better dispersity resulted in more significant changes in the CAT backbone and secondary structure, fluorescence sensitization and enzyme function inhibition. The combined experiments show that the cellular uptake and dispersity of UFCB are the dominating factors for the discrepancy in size-dependent cellular and molecular toxicity, respectively. This study provides a theoretical basis for the necessary circumvention and substitution of UFCB in engineering applications.


Assuntos
Apoptose , Fuligem , Animais , Catalase , Hepatócitos , Camundongos , Estresse Oxidativo , Tamanho da Partícula , Espécies Reativas de Oxigênio , Fuligem/toxicidade
15.
Chemosphere ; 287(Pt 1): 131984, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34438206

RESUMO

Modification and bandgap engineering are proposed to be extremely significant in improving the photocatalytic activity of novel photocatalysts. The current research focused on the fabrication of ultrafast and efficient visible light-responsive ternary photocatalyst containing g-C3N4 nanostructures in conjugation with polypyrrole doped carbon black (PPy-C) and gold (Au) nanoparticles by highly effectual, simple, and straightforward methodology. Various analytical techniques like XRD, FESEM, TEM, XPS, FTIR, and UV-Vis spectroscopy were applied for characterization purposes. The XRD and XPS results confirmed the successful creation of a nanocomposite framework among Au, PPy-C and g-C3N4. The TEM images revealed that bare g-C3N4 holds sheets or layered graphitic structure with sizes ranging from 100 to 300 nm. The sponge-like PPy-C network intermingled perfectly with g-C3N4 sheets along with homogeneously distributed 5-15 nm Au nanoparticles. The band gap energy (Eg) for bare g-C3N4, PPy-C/g-C3N4 and Au@PPy-C/g-C3N4 nanocomposites were found to be 2.74, 2.68, and 2.60 eV, respectively. The photocatalytic activity for all newly designed photocatalysts have been assessed during the degradation of insecticide Imidacloprid and methylene blue (MB) dye, where Au@PPy-C/C3N4 was found to be extremely efficient with ultrafast removal of both imidacloprid and MB in just 25 min of visible light irradiation. It was revealed that the Au@PPy-C/g-C3N4 ternary photocatalyst removed 96.0% of target analyte imidacloprid, which is ⁓ 2.91 times more efficient than bare g-C3N4 in treating imidacloprid. This report provides a distinctly promising, highly effectual and straightforward route to destruct extremely toxic and notorious pollutants and opens a new gateway in the present challenging scenario of environmental concerns.


Assuntos
Nanopartículas Metálicas , Nanocompostos , Catálise , Ouro , Luz , Polímeros , Pirróis , Fuligem
16.
Sci Total Environ ; 803: 150057, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34500269

RESUMO

Black carbon (BC), characterized by high aromaticity and stability, has been recognized as a substantial fraction of the carbon pool in soil and sediment. The effect of BC on the particulate organic carbon (POC) pool in lake water, which is an important medium of carbon transmission and transformation, has not been thoroughly studied. The investigations of BC composition and distribution, POC, polycyclic aromatic hydrocarbons (PAHs), and stable carbon and nitrogen isotopes were conducted in a eutrophic urban lake, Taihu Lake, which is the third largest freshwater lake in China. The results indicate that the BC is composed of 55 ± 12% char and 45 ± 12% soot and accounted for 12 ± 6% of POC (the maximum value is 31%). The comparatively high levels of BC and char are distributed in the northern Taihu Lake, especially in Meiliang Bay (0.72 ± 0.38 mg L-1 and 0.45 ± 0.24 mg L-1). The distribution of soot presents a declining trend from the lakeshore to the central lake, particularly in the northern, western, and southern lakes. Source apportionment results from positive matrix factorization of PAHs suggest that consumption of fossil fuel (79 ± 20%) is the dominant source of BC, which agrees with the low ratio of char/soot (1.41 ± 0.71) and relatively depleted δ13C. The covariation of BC and PAHs and terrestrial dissolved organic carbon indicate that the effect of terrestrial input significantly regulates the distribution of BC in Taihu Lake, which is reflected in the high BC value along the lakeshore.


Assuntos
Lagos , Hidrocarbonetos Policíclicos Aromáticos , Carbono/análise , China , Monitoramento Ambiental , Sedimentos Geológicos , Hidrocarbonetos Policíclicos Aromáticos/análise , Fuligem/análise
17.
Sci Total Environ ; 804: 150209, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34517331

RESUMO

The signals of fire activity induced from climate and ancient human activities could be recorded in sedimentary strata. We examined a 6000-year black­carbon (BC) record-including char and soot-of a sediment core from the South Yellow Sea. The climate change had a threshold effect on the fire regime, and dominated the char emissions. The soot/BC signals depicted that the anthropogenic emissions related to the evolution of the Chinese civilization since the Early Bronze Age (~4 ka) have overwhelmed natural soot emissions. The soot variation in the record closely matched periods when there was large-scale use of coal or charcoal after the Han Dynasty and when indigenous coking technology was promoted after the Tang Dynasty; low soot-abundance in the record coincided with periods of social unrest. This work illustrates how soot signals can be a robust tracer of civilization evolution.


Assuntos
Carbono , Monitoramento Ambiental , Carbono/análise , China , Civilização , Humanos , Fuligem/análise
18.
Sci Rep ; 11(1): 23378, 2021 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-34916540

RESUMO

Emissions of black carbon (BC) particles from anthropogenic and natural sources contribute to climate change and human health impacts. Therefore, they need to be accurately quantified to develop an effective mitigation strategy. Although the spread of the emission flux estimates for China have recently narrowed under the constraints of atmospheric observations, consensus has not been reached regarding the dominant emission sector. Here, we quantified the contribution of the residential sector, as 64% (44-82%) in 2019, using the response of the observed atmospheric concentration in the outflowing air during Feb-Mar 2020, with the prevalence of the COVID-19 pandemic and restricted human activities over China. In detail, the BC emission fluxes, estimated after removing effects from meteorological variability, dropped only slightly (- 18%) during Feb-Mar 2020 from the levels in the previous year for selected air masses of Chinese origin, suggesting the contributions from the transport and industry sectors (36%) were smaller than the rest from the residential sector (64%). Carbon monoxide (CO) behaved differently, with larger emission reductions (- 35%) in the period Feb-Mar 2020, suggesting dominance of non-residential (i.e., transport and industry) sectors, which contributed 70% (48-100%) emission during 2019. The estimated BC/CO emission ratio for these sectors will help to further constrain bottom-up emission inventories. We comprehensively provide a clear scientific evidence supporting mitigation policies targeting reduction in residential BC emissions from China by demonstrating the economic feasibility using marginal abatement cost curves.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , COVID-19/prevenção & controle , Material Particulado/análise , SARS-CoV-2/isolamento & purificação , Fuligem/análise , Algoritmos , Atmosfera/análise , COVID-19/epidemiologia , COVID-19/virologia , China , Mudança Climática , Monitoramento Ambiental/métodos , Monitoramento Ambiental/estatística & dados numéricos , Geografia , Atividades Humanas , Humanos , Modelos Teóricos , Pandemias , Características de Residência , SARS-CoV-2/fisiologia , Estações do Ano , Vento
19.
Water Sci Technol ; 84(9): 2278-2287, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34810311

RESUMO

Ti-based electrode coated with MnOx catalytic layer has presented superior electrochemical activity for degradation of organic pollution in wastewater, however, the industrial application of Ti-based MnOx electrode is limited by the poor stability of the electrode. In this study, the novel Ti-based MnOx electrodes co-incorporated with rare earth (Ce) and conductive carbon black (C) were prepared by spraying-calcination method. The Ti/Ce:MnOx-C electrode, with uniform and integrated surface and enhanced Mn(IV) content by C and Ce co-incorporation, could completely remove ammonia nitrogen (NH4+-N) with N2 as the main product. The cell potential and energy consumption of Ti/Ce:MnOx-C electrode during the electrochemical process was significantly reduced compared with Ti/MnOx electrode, which mainly originated from the enhanced electrochemical activity and reduced charge transfer resistance by Ce and C co-incorporation. The accelerated lifetime tests in sulfuric acid showed that the actual service lifetime of Ti/Ce:MnOx-C was ca. 25 times that of Ti/MnOx, which demonstrated the significantly promoted stability of MnOx-based electrode by Ce and C co-incorporation.


Assuntos
Amônia , Titânio , Eletrodos , Nitrogênio , Oxirredução , Fuligem
20.
J Nanosci Nanotechnol ; 21(6): 3283-3290, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34739783

RESUMO

Hybrid nanofluids, a new class of nanofluid has the ability to further enhance the thermo-physical properties by balancing the benefits of both kinds of nanomaterials as compared with nanofluids synthesized using only one kind of material. In this work, water-based nanofluids containing suspensions of carbon black (CB)-boron nitride (BN) (mass ratio = 50:50) nanoparticles are synthesized and studied for its rheological properties. The viscosity of CB-BN nanofluids are measured at temperatures between 30 °C-60 °C for volume concentrations 0.25 to 2 vol.%. The viscosity shows an increase with increasing particle concentration and decreases with temperature. A non-Newtonian nature with a dilatant behavior in the shear rate range of 5.4 s-1 to 130 s-1 is observed for all concentrations and temperatures. Also, it follows a power law model and its parameters, i.e., power index and consistency index are obtained by the curve fitting method. The non-Newtonian nature intensifies at low temperatures and concentrations. A new correlation is developed to predict the viscosity of CB-BN hybrid nanofluids.


Assuntos
Nanoestruturas , Fuligem , Compostos de Boro , Reologia , Viscosidade
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