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1.
Anal Chem ; 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31895543

RESUMO

Formaldehyde (HCHO) is the most abundant atmospheric carbonyl compound and plays an important role in the troposphere. However, HCHO detection via traditional incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) is limited by short optical path lengths and weak light intensity. Thus, a new light-emitting diode (LED)-based IBBCEAS was developed herein to measure HCHO in ambient air. Two LEDs (325 and 340 nm) coupled by a Y-type fiber bundle were used as an IBBCEAS light source, which provided both high light intensity and a wide spectral fitting range. The reflectivity of the two cavity mirrors used herein was 0.99965 (1 - reflectivity = 350 ppm loss) at 350 nm, which corresponded with an effective optical path length of 2.15 km within a 0.84 m cavity. At an integration time of 30 s, the measurement precision (1σ) for HCHO was 380 parts per trillion volume (pptv), and the corresponding uncertainty was 8.3%. The instrument was successfully deployed for the first time in a field campaign and delivered results that correlated well with those of a commercial wet-chemical instrument based on Hantzsch fluorimetry (R2 = 0.769). The combined light source based on a Y-type fiber bundle overcomes the difficulty of measuring ambient HCHO via IBBCEAS in near-ultraviolet range, which may extend IBBCEAS technology to measure other atmospheric trace gases with high precision.

2.
Environ Sci Technol ; 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31722174

RESUMO

The hygroscopic properties of BC-containing particles (BCc) are important to determine their wet scavenging, atmospheric lifetime, and interactions with clouds. Such information is still lacking in the real world because of the challenges in isolating BCc from other aerosols to be directly characterized. In this study, the size-resolved chemical components of BCc including the refractory BC core and associated coatings were measured by a soot particle-aerosol mass spectrometer in suburban Nanjing. The size-resolved hygroscopicity parameter of BCc (κBCc) was obtained based on this full chemical characterization of BCc. We found increased inorganic fraction and more oxidized organic coatings with thicker coatings, which modified κBCc besides the determinant of particle size. The bulk κBCc was observed to range from 0.11 to 0.34. The size-resolved κBCc consistently showed minima at coated diameter (Dcoated) of 100 nm, parametrized as κ(x) = 0.28-0.35 × exp(-0.004 × x), x = Dcoated. Under critical supersaturations (SS) of 0.1% and 0.2%, the D50 values of BCc were 200 ± 20 and 135 ± 18 nm, respectively. On average 33 ± 16% and 59 ± 20% of BCc in number could be activated at SS = 0.1% and 0.2%, respectively. These results provide constraints on surface CCN sources for the light-absorbing BC-containing particles.

3.
Sci Total Environ ; 685: 976-985, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31390715

RESUMO

Secondary organic aerosol (SOA) species formed in atmospheric aqueous phases is recently recognized as an important contributor to fine aerosols, which is known to be a prominent human health risk factor internationally. This work, for the first time, systematically investigated aqueous-phase photochemical oxidation of 4-ethylphenol (4-EP) - a model compound from biomass burning and a surrogate of intermediate volatility organic compounds, under both ultraviolet (UV) (Hg lamp) and simulated sunlight (Xe lamp). We found that 4-EP could degrade upon hydroxal radical (OH) oxidation under UV light nearly 15 times faster than that under simulated sunlight, but large aqueous SOA (aqSOA) yields (108%-122%) were observed under both situations. AqSOA masses and oxidation states continuously increased under simulated sunlight, yet they increased first then decreased quickly under UV light. We proposed a reaction scheme based on identified products, showing that oligomerization, functionalization and fragmentation all can occur during 4-EP oxidation. Our results demonstrate that OH radical may suppress oligomerization and functionalization, but is favorable for fragmentation. Under UV light with H2O2 (high OH), fragmentation was dominant, producing more volatile and smaller molecules, and less aqSOA in later oxidation; Under simulated sunlight with H2O2 (moderate OH), functionalization that can form hydroxylated monomer was more important. Moreover, 4-EP oxidation by the organic triplet excited state (3C*) could form species with stronger visible light absorptivity than those from OH-mediated oxidation, and the absorptivity showed positive link with contents of humic-like substances.

4.
Oncol Lett ; 18(1): 838-845, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31289561

RESUMO

Lung cancer is the leading cause of cancer-associated mortality worldwide. Previous studies have demonstrated that long non-coding RNAs (lncRNAs) serve important roles in diverse biological processes. However, the molecular function and prognostic value of the majority of lncRNAs in non-small cell lung cancer (NSCLC) remain unknown. The present study investigated the expression of the lncRNA GABPB1 intronic transcript (GABPB1-IT1) in NSCLC tissues using publicly available databases. Subsequently, protein-protein interaction (PPI) and co-expression networks were constructed to identify key targets of lncRNA GABPB1-IT1. Furthermore, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed to investigate the potential roles of lncRNA GABPB1-IT1. The current study identified that the expression of GABPB1-IT1 was significantly downregulated in NSCLC samples compared with normal samples. Furthermore, the expression levels of GABPB1-IT1 were lower in high grade NSCLC samples compared with low grade NSCLC samples. Additionally, overexpression of GABPB1-IT1 in cancer samples was associated with improved survival of patients with NSCLC. GABPB1-IT1 was revealed to be involved in the regulation of cell cycle-associated biological processes, including sister chromatid cohesion, mitotic nuclear division, DNA replication, chromosome segregation, G1/S transition of mitotic cell cycle, mitotic cytokinesis and cell division. Finally, a GABPB1-IT1-associated protein-protein interaction network was constructed for NSCLC. To the best of our knowledge, the present study was the first to demonstrate that GABPB1-IT1 is associated with the prognosis of NSCLC. The current study provides useful information to assist with the investigation of potential candidate biomarkers for diagnosis, prognosis and drug targets for NSCLC.

5.
Sci Total Environ ; 678: 301-308, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31075597

RESUMO

Heavy metals are widely recognized as toxic components in urban air particulate matter (PM). However, the major toxic metals and their interactions are poorly understood. In this study, we attempted to explore the toxicity contribution and combined effects of PM-bounded metals in human lung epithelial cells (A549). Real-time cell analysis indicated that the critical toxic concentration (EC50) of PM detected in this study was 107.90 mg/L (r2 = 1.00, p < 0.01). The cell viability of A549 increased significantly (12.3%) after metal removal in PM, demonstrating an important contribution of metal components to PM toxicity. Among eleven elements examined (Zn, Cr, Mn, Fe, Ni, Cu, As, Se, Sr, Cd, and Pb), six heavy metals (Zn, Cr, Mn, Fe, Cu, and Pb) might account for PM toxicity in A549 cells, and their co-exposure led to a high mortality of A549 cells (36.5 ±â€¯7.3%). For combination treatments, cell mortality caused by single or multiple metal mixtures was usually alleviated by Fe addition, while it was often aggravated in the presence of Mn. The varying effects of other metals (Zn, Cu, Pb and Cr) on different metal mixtures might be explained by their interactions (e.g., similar or dissimilar membrane transporters and intracellular targets). Furthermore, the concentration addition model (CA), independent action model (IA), integrated addition model (IAM) and integrated addition and interaction model (IAI) were used to predict mixture toxicity, and the IAI model exhibited the least variation between observed and predicted toxic effects (r2 = 0.87, p < 0.01). Our results highlight the potential contribution from heavy metals and their interactions to PM toxicity, and promote the application of toxicity prediction models on metal components in PM.


Assuntos
Poluentes Atmosféricos/toxicidade , Pulmão/efeitos dos fármacos , Metais Pesados/toxicidade , Material Particulado/toxicidade , Células A549 , Humanos , Testes de Toxicidade
6.
Nanoscale ; 11(11): 5058-5063, 2019 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-30839967

RESUMO

Hydrogen peroxide has been widely studied in cell biology and liquid fuel cells as an oxidant or fuel, and highly efficient and durable electrocatalysts for H2O2 reduction and detection are in high demand. Here, a simple strategy to fabricate conductive 2D single/several-layer [Co3(HHTP)2]n MOF nanosheets, based on 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) and Co2+ ions, was developed by the Langmuir-Blodgett (LB) method combined with layer-by-layer (LbL) growth technology. The [Co3(HHTP)2]n MOF nanosheets successfully boosted H2O2 reduction with ultrahigh mass activity and good durability, and a new method to detect the H2O2 concentration with an ultralow detection limit of 10-7 (2.9 µmol L-1) was developed. Meanwhile, a series of factors like layer number, surface tension, pH value, ion concentration, and annealing were systematically investigated to further prove the ultrahigh accuracy, sensitivity, and durability of the as-developed H2O2 detection method. The reaction mechanism and energy transfer process of H2O2 reduction catalyzed by the metal-organic nanosheets were investigated by first principles calculations using density functional theory (DFT), showing good agreement with the experiment.

7.
J Nanosci Nanotechnol ; 19(6): 3059-3078, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30744732

RESUMO

The carbon dioxide (CO2) is notorious as the greenhouse gas, which could cause the global warming and climate change. Therefore, the reduction of the atmospheric CO2 emissions from power plants and other industrial facilities has become as an increasingly urgent concern. In the recent years, CO2 capture and storage technologies have received a worldwide attention. Adsorption is considered as one of the efficient options for CO2 capture because of its cost advantage, low energy requirement and extensive applicability over a relatively wide range of temperature and pressure. The metal organic frameworks (MOFs) show widely potential application prospects in CO2 capture and storage owing to their outstanding textural properties, such as the extraordinarily high specific surface area, tunable pore size, ultrahigh porosity (up to 90%), high crystallinity, adjustable internal surface properties, and controllable structure. Herein, the most important research progress of MOFs materials on the CO2 capture and storage in recent years has been comprehensively reviewed. The extraordinary characteristics and CO2 capture performance of Zeolitic Imidazolate Frameworks (ZIFs), Bio-metal organic frameworks (bio-MOFs), IL@MOFs and MOF-composite materials were highlighted. The promising strategies for improving the CO2 adsorption properties of MOFs materials, especially the low-pressure adsorption performance under actual flue gas conditions, are also carefully summarized. Besides, CO2 is considered as an abundant, nontoxic, nonflammable, and renewable C1 resource for the synthesis of useful chemicals and fuels. The potential routes for resource utilization of the captured CO2 are briefly proposed.

8.
Environ Sci Pollut Res Int ; 26(10): 9672-9685, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30734252

RESUMO

Photocatalytic oxidation of formaldehyde (HCHO) is considered as one of the promising ways to resolve indoor air HCHO pollution. TiO2 has been well known as the most extended application in photocatalysis due to its strong oxidizing ability and stability. Owing to high activity under visible light irradiation, TiO2 and Bi2O3 doping mixed with Bi2WO6 was analyzed in this study. The formation of two kinds of heterojunction caused efficient charge separation, leading to the effective reduction in the recombination of photo-generated electron and hole. The special structure and enhanced performance of these catalysts were analyzed. For the first time, the loading of alkali salts was researched for photocatalytic oxidation. In order to understand the reaction mechanism of alkali salts enhanced effects, the catalysts were investigated by using BET, XRD, UV-Vis, FT-IR, SEM, and XPS. The results found more than 2 wt% of Na2SO4 loading and the mixed methods with different solutions were key factors affecting the performance of catalysts. Nearly 92% HCHO conversion could be completed over Bi2WO6/Bi0.15Ti0.85O2 (Na2SO4), and the concentration of HCHO was only 0.07 mg/m3 for 24 h, which was below the limit of specification in China. The results also indicated that the solution mixing method was more favorable to increase the HCHO conversion due to decrease the size of Bi0.15Ti0.85O2 particles. The catalysts with Na2SO4 loading provided more surface-adsorbed oxygen that facilitated the desorption of CO2 and markedly increased the photocatalytic oxidation of HCHO. Graphical abstract Plausible mechanism over W-Bi2WO6/ Bi0.15Ti0.85O2-Na2SO4 (1:4) catalysts.


Assuntos
Formaldeído/química , Modelos Químicos , Adsorção , Poluição do Ar em Ambientes Fechados/análise , Álcalis , Bismuto/química , Catálise , China , Luz , Oxirredução , Oxigênio , Processos Fotoquímicos , Espectroscopia de Infravermelho com Transformada de Fourier , Titânio/química , Compostos de Tungstênio/química
9.
Materials (Basel) ; 12(2)2019 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-30654472

RESUMO

In the past two decades, great progress has been made in the aspects of fabrication and application of ordered mesoporous metal oxides. Ordered mesoporous metal oxides have attracted more and more attention due to their large surface areas and pore volumes, unblocked pore structure, and good thermal stabilities. Compared with non-porous metal oxides, the most prominent feature is their ability to interact with molecules not only on their outer surface but also on the large internal surfaces of the material, providing more accessible active sites for the reactants. This review carefully describes the characteristics, classification and synthesis of ordered mesoporous metal oxides in detail. Besides, it also summarizes the catalytic application of ordered mesoporous metal oxides in the field of carbon dioxide conversion and resource utilization, which provides prospective viewpoints to reduce the emission of greenhouse gas and the inhibition of global warming. Although the scope of current review is mainly limited to the ordered mesoporous metal oxides and their application in the field of CO2 catalytic conversion via heterogeneous catalysis processes, we believe that it will provide new insights and viewpoints to the further development of heterogeneous catalytic materials.

10.
Huan Jing Ke Xue ; 40(1): 94-103, 2019 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-30628263

RESUMO

To understand the characteristics and sources of water-soluble organic carbon (WSOC) and organic nitrogen (WSON) in atmospheric aerosols during spring in Changzhou, 84 fine particle (PM2.5) samples were collected from March 1 to May 30, 2017, in Changzhou. The water-soluble components, including water-soluble organic carbon, water-soluble total nitrogen (WSTN), water-soluble ions, and carbonaceous components (OC and EC), were analyzed. The levels of WSOC and WSON and their source characteristics were discussed. The results show that the average concentrations of PM2.5, WSOC, and WSON are 101.97, 7.63, and 1.50 µg·m-3, respectively, during the sampling period. The WSON accounts for 12.9% of the WSTN and the water-soluble inorganic nitrogen mainly exists in two forms, that is, NH4+ and NO3-, accounting for 86.15% of the WSTN. The WSOC is weakly correlated with WSON (r=0.58), indicating that WSOC and WSON do not have the same sources. The WSOC is related to SOC, K+, and secondary ions (SO42-, NH4+, and NO3-), indicating that it is mainly derived from biomass burning and secondary conversion; WSON is strongly correlated to secondary ions, indicating that it is mainly derived from secondary conversion. The wind speed is the main factor affecting the WSOC and WSON concentration levels. Furthermore, the WSON is positively correlated with the air pressure and negatively correlated with the temperature. The results of the principal component analysis show that PM2.5 mainly originates from four sources:secondary formation, dust, coal combustion, biomass burning, and the ocean. The backward trajectory analysis indicates that the total concentrations of PM2.5, WSOC, and WSON in air masses from long-distance transformation are higher than that from short-distance transmission, whereas there is no significant difference in the WSON/WSTN ratio from different transmission paths.

11.
Sci Total Environ ; 646: 1567-1577, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30235641

RESUMO

The activated bio-chars (AB) were successfully synthesized from rice husk by one- and two-step KOH-catalyzed pyrolysis. The two-step pyrolysis can produce the high yields of AB compared to the one-step pyrolysis. Moreover, the yield of AB decreased with the increase of the mass ratio of KOH and char, which had a significant effect on the development of the surface area and porosity of carbon. In particular, the AB derived from the two-step pyrolysis at 750°C (mass ratio of KOH and char was 3) had the highest specific surface area (SBET=2138m2/g) with many micro-porous structures, which was favored for the phenol adsorption. The maximum adsorption capacity of AB2-3-750 reached 201mg/g because of its excellent surface porosity property. The phenol can be efficiently removed from water by only several minutes. The Langmuir model defined well the adsorption isotherm with a high correlation coefficient value, indicating a monolayer adsorption behavior. And the adsorption process defined well with the pseudo-second-order model. The phenol molecules passed into the internal surface via the liquid-film controlled diffusion, so the behavior of phenol adsorption onto the AB was predominantly controlled via the chemisorption. Furthermore, the functional groups on the outer surfaces of AB can attract the phenol molecules onto the internal surfaces via "π-π dispersion interaction" and "donor-acceptor effect".


Assuntos
Carvão Vegetal/química , Hidróxidos/química , Fenol/metabolismo , Compostos de Potássio/química , Adsorção , Modelos Químicos , Oryza , Fenóis
12.
Environ Technol ; 40(15): 1937-1947, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29364059

RESUMO

Bi2O3/TiO2 photocatalysts were prepared by a hydrothermal method. The photocatalysts were applied to the catalytic oxidation of indoor formaldehyde vapors under irradiation by an light-emitting diode energy-saving lamp. The characterization methods including Brunauer-Emmett-Teller, X-ay diffraction, UV-vis spectra, scanning electron microscopy, Transmission electron microscopy and X-ray photoelectron spectroscopy analysis were used to investigate the crystalline structure, morphology, specific surface area and porosity. The effects of the preparation conditions, including the type of alcohols, molar ratio and calcination temperature, on the morphology, structure and crystalline phase of the catalyst were also investigated. The results reveal that the morphology could be controlled by using different types of alcohols, especially mixed alcohols. The morphology played a key role in determining the photodegradation efficiency of formaldehyde. According to the experimental results, the Bi2O3/TiO2 catalysts with amorphous particles showed the highest activity. The presence of anatase TiO2 and Bi4(TiO4)3 with a heterojunction structure was the main reason for the high activity, and they were beneficial for increasing the separation of the photogenerated electrons and holes and decreasing their recombination through electron transformations.


Assuntos
Álcoois , Titânio , Catálise , Oxirredução , Espectroscopia Fotoeletrônica , Fotólise
13.
Chem Commun (Camb) ; 54(96): 13579-13582, 2018 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-30444509

RESUMO

A new class of 2D fewer-layer π-conjugated conductive metal-organic nanosheets was developed via the Langmuir-Blodgett method, exhibiting ultrahigh mass activity (64.63 A mg-1, 1.7 V vs. RHE) and stability for electrochemical oxygen evolution reactions (OER).

14.
Environ Technol ; : 1-13, 2018 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-30379618

RESUMO

A series of MnOx-CeO2 catalysts with MOx doping (M = Cu, Fe, Co and La) supported on cordierite were synthesized by the citric acid complex method, showing preferable catalytic oxidation of chlorobenzene. The distribution of active oxides, surface areas, as well as the structural morphology of M-MnOx-CeO2 catalysts varied with the different Mn/Ce and M/Mn molar ratios. Meanwhile, physicochemical properties of these catalysts were characterized by XRD, BET, SEM, TEM, H2-TPR and IR. More importantly, the catalytic oxidation routes were also investigated where the process was from chlorobenzene to CO2, H2O, HCl and other by-products for the FeOx-MnOx-CeO2 and CuO-MnOx-CeO2 catalysts. The CuO-MnOx-CeO2 catalysts showed a higher chlorobenzene conversion, and the measured light-off temperature T90 was approximately 400°C. However, a large amount of chloropropane as main by-products was observed. For the FeOx-MnOx-CeO2 catalysts, more carbon monoxide could be found with inadequate oxidation. Comparative analyses of two catalysts indicated that the main cause of the oxidation activities and mechanisms were different in the oxidation capacity and water absorbability of FeOx and CuO. Nevertheless, all of these catalysts did not exhibit any deactivation due to chloride with a high reaction temperature, with chloride transformed to form HCl in the off-gas stream.

15.
Materials (Basel) ; 11(11)2018 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-30441828

RESUMO

The initiation and evolution of the localized corrosion in carbon steel were investigated in a simulated marine environment of Xisha Island in the South China Sea. In the initial stage, localized corrosion occurred in the form of corrosion spot. The localized corrosion morphology and electrochemical information during corrosion process were tracked by field emission scanning electron microscopy energy dispersive spectrometry (FE-SEM-EDS), scanning vibrating electrode technique (SVET) and scanning Kelvin probe force microscopy (SKPFM). Localized corrosion was induced by the microcrevices around Al2O3 inclusions. The occluded cells and oxygen concentration cell formed in the pits could accelerate the localized corrosion. Pearlite accelerated the dissolution of the inside and surrounding ferrite via the galvanic effect between Fe3C and ferrite. Overall, the localized corrosion was initiated and evaluated under a synergistic effect of crevice corrosion, occluded cells, oxygen concentration cell and the galvanic couple between FeC3 and ferrite.

16.
Front Chem ; 6: 393, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30333968

RESUMO

BiOCl/NaNbO3 p-n heterojunction photocatalysts with significantly improved photocatalytic performance were fabricated by a facile in-situ growth method. The obtained BiOCl/NaNbO3 samples were characterized by UV-vis absorption spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), photocurrent (PC) and photoluminescence spectroscopy (PL). The photocatalytic activity of the BiOCl/NaNbO3 samples was investigated by the degradation of a typical antibiotic Ofloxacin (OFX). The experimental results showed that BiOCl/NaNbO3 composites exhibited much higher photocatalytic activity for OFX degradation compared to pure NaNbO3 and BiOCl. The degradation percent of OFX reached 90% within 60 min, and the apparent rate constant was about 8 times as that of pure NaNbO3 and BiOCl. The improved activity can be attributed to the formation of p-n junction between NaNbO3 and BiOCl. The formed p-n junction facilitated the separation of photogenerated holes and electrons, thereby enhancing photocatalytic activity. In addition, the composite photocatalyst showed satisfactory stability for the degradation of OFX. Due to the simple synthesis process, high photocatalytic activity, and the good recyclability of these composite photocatalysts, the results of this study would provide a good example for the rational design of other highly efficient heterojunction photocatalytic materials.

17.
Bioresour Technol ; 269: 67-73, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30149256

RESUMO

This paper studied the KOH-catalyzed pyrolysis of rice husk (RH) and its pellet (RHP) at a high temperature (750 °C) for activated bio-carbons production. The mass ratio of KOH and biomass greatly impacted the pyrolysis kinetic and biochar property. The KOH catalysis (mass ratio: 1) reduced significantly the activation energy to 41 kJ/mol. During carbonization with KOH, the in-situ generated K2CO3 tailored the morphology and size of the self-template (SiO2 nanoparticles), giving rise to the chars with the open foam-like porous architectures enrich in micro- and meso-pores. Thus, the KOH activation via one-step pyrolysis could produce the micro-mesoporous carbons (e.g., RH-char 1 and RHP-char 1) with high specific surface areas and high content of oxygen-functionalities. Furthermore, the hierarchical porous carbons have high potential applications in adsorption process and electrochemical energy storage (e.g., supercapacitor) because of their unique physicochemical properties.


Assuntos
Carbono/química , Oryza , Adsorção , Catálise , Dióxido de Silício
18.
J Environ Manage ; 214: 94-103, 2018 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-29518601

RESUMO

This work studied the disposal of the non-metallic fraction from waste printed circuit board (NMF-WPCB) via the chemical pretreatments followed by pyrolysis. As a main heavy metal, the metallic Cu could be significantly removed by 92.4% using the HCl leaching process. Subsequently, the organic-Br in the brominated flame retardants (BFRs) plastics could be converted into HBr by pyrolysis. The alkali pretreatment was benefit for the Br fixation in the solid char. The Br fixation efficiency could reach up to 53.6% by the NaOH pretreatment followed by the pyrolysis process. The formed HBr could react with NaOH/KOH to generate the stabilized NaBr/KBr. Therefore, the integrated chemical pretreatment could be used for the eco-friendly disposal of the NMF-WPCB via pyrolysis.


Assuntos
Resíduo Eletrônico , Plásticos , Retardadores de Chama , Metais Pesados
19.
Artigo em Inglês | MEDLINE | ID: mdl-29584626

RESUMO

Particulate matter (PM) air pollution has become a serious environmental problem in Nanjing and poses great health risks to local residents. In this study, characteristics of particulate matter with an aerodynamic diameter less than 2.5 µm (PM2.5) over Nanjing were analyzed using hourly and daily averaged PM2.5 concentrations and meteorological parameters collected from nine national monitoring sites during the period of March 2014 to February 2017. Then, the integrated exposure-response (IER) model was applied to assess premature mortality, years of life lost (YLL) attributable to PM2.5, and mortality benefits due to PM2.5 reductions. The concentrations of PM2.5 varied among hours, seasons and years, which can be explained by differences in emission sources, secondary formations and meteorological conditions. The decreased ratio of PM2.5 to CO suggested that secondary contributions decreased while the relative contributions of vehicle exhaust increased from increased CO data. According to the values of attributable fractions (AF), stroke was the major cause of death, followed by ischemic heart disease (IHD), lung cancer (LC) and chronic obstructive pulmonary disease (COPD). The estimated total deaths in Nanjing due to PM2.5 were 12,055 and 10,771, leading to 98,802 and 87,647 years of life lost in 2014 and 2015, respectively. The elderly and males had higher health risks than youngsters and females. When the PM2.5 concentrations meet the World Health Organization (WHO) Air Quality Guidelines (AQG) of 10 µg/m³, 84% of the premature deaths would be avoided, indicating that the Nanjing government needs to adopt more stringent measure to reduce PM pollution and enhance the health benefits.


Assuntos
Poluentes Atmosféricos/análise , Neoplasias Pulmonares/mortalidade , Mortalidade Prematura , Isquemia Miocárdica/mortalidade , Material Particulado/análise , Doença Pulmonar Obstrutiva Crônica/mortalidade , Acidente Vascular Cerebral/mortalidade , Adulto , Idoso , Monóxido de Carbono/análise , China/epidemiologia , Monitoramento Ambiental , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho da Partícula , Emissões de Veículos
20.
Ecotoxicol Environ Saf ; 153: 68-77, 2018 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-29407740

RESUMO

Laboratory analysis of trace metals using inductively coupled plasma (ICP) spectroscopy is not cost effective, and the complex spatial distribution of soil trace metals makes their spatial analysis and prediction problematic. Thus, for the health risk assessment of exposure to trace metals in soils, portable X-ray fluorescence (PXRF) spectroscopy was used to replace ICP spectroscopy for metal analysis, and robust geostatistical methods were used to identify spatial outliers in trace metal concentrations and to map trace metal distributions. A case study was carried out around an industrial area in Nanjing, China. The results showed that PXRF spectroscopy provided results for trace metal (Cu, Ni, Pb and Zn) levels comparable to ICP spectroscopy. The results of the health risk assessment showed that Ni posed a higher non-carcinogenic risk than Cu, Pb and Zn, indicating a higher priority of concern than the other elements. Sampling locations associated with adverse health effects were identified as 'hotspots', and high-risk areas were delineated from risk maps. These 'hotspots' and high-risk areas were in close proximity to and downwind from petrochemical plants, indicating the dominant role of industrial activities as the major sources of trace metals in soils. The approach used in this study could be adopted as a cost-effective methodology for screening 'hotspots' and priority areas of concern for cost-efficient health risk management.


Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Oligoelementos/análise , China , Análise Custo-Benefício , Monitoramento Ambiental/estatística & dados numéricos , Humanos , Indústrias , Medição de Risco/métodos , Medição de Risco/estatística & dados numéricos , Análise Espacial , Espectrometria por Raios X
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