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Ingestion of plastic fragments by the Guri sea catfish Genidens genidens (Cuvier, 1829) in a subtropical coastal estuarine system
2019
Dantas, David V. | Ribeiro, Cristian I. R. | Frischknecht, Catarina de C. A. | Machado González Prada, Rodrigo | Farias, Eduardo G. G.
One of the most recognized anthropogenic impacts in marine environments is solid waste pollution, especially plastic, which can be ingested by fish, thus interfering with their health. In this context, the aim of this study is to describe the ingestion of plastic fragments and to identify the possible effect of this contamination in the condition factor of Genidens genidens in the Laguna Estuarine System. The stomach contents of 92 G. genidens (26 juveniles and 66 adults) were analyzed. The Index of Relative Importance was performed to identify the contribution of each prey item. Condition factor (CF) was used to analyze the effect of plastic ingestion on the fish’s body condition (by comparing individuals in the same ontogenetic phase). For the juveniles, eight items were observed, the most important of which were Penaeidae, followed by Portunidae and plastic. For the adults, 12 items were observed, the most important of which were Penaeidae, Portunidae, Polychaeta, and plastic. The analysis of CF demonstrated higher values for individuals without plastic in the stomach, which indicated a better health condition. The CF of a fish may be affected by variations in the physiological condition, environmental stresses, and nutritional and biological variations, and could be used to compare the body condition or health of a fish species. The ingestion of plastic could significantly influence the worst body condition of the individuals that were analyzed in the present study. The plastic pollution in marine coastal waters is associated with the appropriate waste management levels.
显示更多 [+] 显示较少 [-]Synthesis and characterization of Ag2O/B2O3/TiO2 ternary nanocomposites for photocatalytic mineralization of local dyeing wastewater under artificial and natural sunlight irradiation
2019
Tijani, Jimoh Oladejo | Momoh, Ufon Ojogbane | Salau, Rasaq Bolakale | Bankole, Mercy Temitope | Abdulkareem, Ambali Saka | Roos, Wiets Dániel
In this work, Ag₂O/B₂O₃/TiO₂ ternary nanocomposite was synthesized by a combination of green and precipitation method involving mixing of different concentrations of silver nitrate, boric acid, and titanium (IV) isopropoxide precursor with Plumeria acuminate leaf extract. The extract was obtained by boiling the mixture of distilled water and the powdered leaves in a beaker for few minutes followed by filtration. The microstructure, morphology, chemical composition, surface area, phase structure, and optical properties of the various prepared nanomaterials were determined by HRTEM, HRSEM, UV-Vis/DRS, BET, XRD, and XPS. The photocatalytic potential of TiO₂ nanoparticles and Ag₂O/B₂O₃/TiO₂ nanocomposites to degrade local dyeing wastewater under artificial and natural sunlight irradiation was investigated. The extent of degradation of the organic pollutants was measured using chemical oxygen demand (COD) and total organic carbon (TOC) as indicator parameters. The XRD pattern of Ag₂O/B₂O₃/TiO₂ nanocomposites revealed that the formation of pure anatase TiO₂ phase and the addition of both silver and boron precursors did not influenced the phase structure of the nanocomposites. The oxidation states of +1 and +3 for both Ag and B on the surface of Ag₂O/B₂O₃/TiO₂ nanocomposites were confirmed by XPS. Optical characterization of the sample revealed reduction of band gap energy from 2.6 to 2.0 eV for TiO₂ and Ag₂O/B₂O₃/TiO₂, respectively. The Ag₂O/B₂O₃/TiO₂ nanocomposites demonstrated excellent photocatalytic activity under natural sunlight and artificial light than mono and binary oxide systems with TOC and COD degradation efficiencies of 86.11% and 75.69%, respectively. The kinetics of degradation of organic dyes in the wastewater followed the order of Langmuir–Hinshelwood pseudo-first-order > Freundlich > Zero > Parabolic diffusion model. The coupling effect of Ag₂O and B₂O₃ onto TiO₂ framework was responsible for the enhanced photochemical stability of the nanocomposites even after five repeated cycles.
显示更多 [+] 显示较少 [-]Electrokinetic remediation of antibiotic-polluted soil with different concentrations of tetracyclines
2019
Li, Binxu | Zhang, Zhiguo | Ma, Yanlin | Li, Yanling | Zhu, Changxiong | Li, Hongna
This study investigated the efficacy of electrokinetic remediation of soils polluted with different concentrations of tetracyclines (TCs). Three widely used TCs (oxytetracycline, chlortetracycline, and tetracycline) were selected, and concentrations of 0, 5, 10, 20, and 50 mg/kg (C0, C5, C10, C20, C50) were selected for comparison. Antibiotic-polluted soils with no electric field served as controls. The average removal rates of TCs in different treatments ranged from 25 to 48% after 7-day remediation. The contributing ratios of electrokinetics to TCs removal varied from 22 to 84%. The concentrations of NH₄⁺ increased in soils and electrolytes, which indicated the decomposition of TCs in the electric field. The highest removal amount of TCs was obtained in the C50 treatment, due to efficient reactions of TCs with oxidative radicals generated during the electrolysis. The fluctuant range of pH in the electrolytes was decreased with increasing concentration of TCs, while the soil pH was increased. The removal rate of antibiotic-resistant bacteria (ARB) in the C5 treatment was significantly higher than that in other treatments. The abundance of antibiotic resistance genes (ARGs) increased with the concentrations of TCs in soils. It might result from the induction of increasing selective pressure of antibiotics. Significant removal of ARGs occurred in the C50 treatment (38–60%). In terms of controlling ARB and ARGs, which were more resistant, the electrokinetic technology showed advantageous effects. Above all, electrokinetic technology provides an effective remediation method, especially for TC-polluted soil with a concentration of 20–50 mg/kg.
显示更多 [+] 显示较少 [-]Construction of precious metal-loaded BiOI semiconductor materials with improved photocatalytic activity for microcystin-LR degradation
2019
Zhang, Fan | Peng, Hui | Jiang, Qishao | Wang, Chuqiao | Xu, Xia | Wang, Liping
The composite photocatalyst of precious metal loaded on BiOI (M/BiOI, M = Pt, Au, Ag) was prepared by photochemical deposition and used for the photocatalytic degradation of microcystins (MC-LR). The material was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), ultraviolet visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), and photoluminescence spectra (PL). The effect of photodegradation of MC-LR and the possible mechanism were investigated. It turned out that, among precious metals of Pt, Au, and Ag, Ag had the most significant improvement for photocatalytic activity of BiOI and Au was the least. The Ag/BiOI catalyst was illuminated 2 h under the simulated visible-light condition with the optimal load ratio of Ag catalyst (1.0 wt%) and the 2-h illumination under simulated visible-light condition, the degradation rate of MC-LR was 61.26% ± 0.12%. In addition, through the experiment of trapping agent and the analysis of electron spin resonance (ESR), we could conclude that the main active species is O₂⁻ in the process of the degradation of MC-LR by three precious metal-loaded BiOI semiconductor materials.
显示更多 [+] 显示较少 [-]Simultaneous removal of nitrogen oxides and sulfur dioxide using ultrasonically atomized hydrogen peroxide
2019
Wei, Jiaqi | Gu, Junjie | Guo, Junheng | Li, Wei | Wang, Chenglong | Zhang, Jinli
A new method was developed for denitrification and desulfurization using hydrogen peroxide with the aid of an ultrasonic nebulizer to obtain high removal efficiency of NOx and SO₂. Comparing with the atomizing nozzles having the aperture size of 0.01~0.02 mm, the droplets generated using the ultrasonic nebulizer show the smallest d₅₀ value of 7.2 μm, with 72% possessing the size less than 10 μm. Based on the numerical simulation of the vaporization rate of droplets, it is indicated that the droplets with the size of 7.2 μm can be vaporized totally at very short residence time (0.11 s) under 130 °C. Effects of influence factors including the reaction temperature, the initial H₂O₂ concentration, pH value, and the flue gas flow rate were studied on the removal efficiencies of NO and SO₂. Using the in-series double-oxidation subsystems with H₂O₂ concentration of 6 wt%, pH 5.0, and the reaction temperature of 130 °C, the removal efficiencies of SO₂ and NO are respectively 100% and 89.3% at the short residence time of 1.8 s, and the removal efficiency of NO can be increased to 100% as the residence time is longer than 3.7 s. It is confirmed that the ultrasonically atomized H₂O₂ can indeed enhance the removal efficiencies of NO and SO₂ at the optimal temperature, owing to the fast vaporization rate of fine droplets as well as the formation of more active radicals to be captured by NO and SO₂ simultaneously. The results here provide a promising route to remove effectively the emissions of NO and SO₂ simultaneously. Graphical abstract
显示更多 [+] 显示较少 [-]Technologies for deodorization of malodorous gases
2019
Wysocka, Izabela | Gębicki, Jacek | Namieśnik, Jacek
There is an increasing number of citizens’ complaints about odor nuisance due to production or service activity. High social awareness imposes pressure on entrepreneurs and service providers forcing them to undertake effective steps aimed at minimization of the effects of their activity, also with respect to emission of malodorous substances. The article presents information about various technologies used for gas deodorization. Known solutions can be included into two groups: technologies offering prevention of emissions, and methodological solutions that enable removal of malodorous substances from the stream of emitted gases. It is obvious that the selection of deodorization technologies is conditioned by many factors, and it should be preceded by an in-depth analysis of possibilities and limitations offered by various solutions. The aim of the article is presentation of the available gas deodorization technologies as to facilitate the potential investors with selection of the method of malodorous gases emission limitation, suitable for particular conditions.
显示更多 [+] 显示较少 [-]Concentrations of particulate matter, carbon dioxide, VOCs and risk assessment inside Korean taxis and ships
2019
Kim, Ho-Hyun | Park, Gee-Young | Lee, Jeong-Hun
The objective of this study was to investigate the concentration distribution of indoor air pollutants in taxis and ships (passengers) which are frequently used for public transportation and recreational activities in South Korea. In addition, it aimed to assess air quality factors to establish and evaluate the health risks of exposure to polluted indoor air. Particulate matter (PM₁₀) concentrations were not affected by the number of passengers, time of day, and driving characteristics because there were only a few passengers (2 to 4 people) and the space was confined. In the ships, indoor air pollutants responded more sensitively to the operation characteristics depending on the time of sailing (i.e., anchoring and departure, movement of vehicles on the ship, movement of passengers, combustion in the shop, and ventilation) than to the number of people boarding and alighting. The carbon dioxide concentrations in different ship rooms did not vary according to season and degree of congestion; however, there were differences between different ships. These differences may result from the size, type, and operating characteristics of the ships. Volatile organic compounds (VOCs) and aldehydes in new taxis exceeded the standard levels during summer. VOC concentrations in ships were particularly high during summer when the outdoor temperature was high. Similar observations were made for other means of transportation. The risk assessment depended on the means of transportation and demonstrated that mortality risks due to PM₁₀ and excess carcinogenic and non-carcinogenic risks from VOCs and aldehydes were within safety levels.
显示更多 [+] 显示较少 [-]Trace elements and human health risks assessment of finer aerosol atmospheric particles (PM1)
2019
Caggiano, Rosa | Sabia, Serena | Speranza, Antonio
The present study investigated PM₁ (aerosol particles with an aerodynamic diameter ≤ 1.0 μm) mass concentrations and sixteen (Al, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, S, Ti, and Zn) PM₁-related trace elements. PM₁ samples were collected in an anthropized area of international attention close to oil/gas pre-treatment plants in Agri Valley (Southern Italy). The PM₁ mass concentrations varied from 3 to 16 μg/m³. The decreasing pattern of the trace element concentrations was S > Ca > Na > K ≈ Mg ≈ Fe> Al > Li > Cr > Zn > Ti> Cu > Ni ≈ Mn > Pb ≈ Cd. Anthropogenic local emissions such as biomass burning, vehicular traffic, and industrial sources mainly related to oil/gas pre-treatment plants were identified by the principal component analysis. Further, air mass back-trajectory analyses suggest an important contribute to the long-range transport on PM₁ at Agri Valley. The carcinogenic (Cd, Cr(VI), Ni, and Pb) and non-carcinogenic (Cd, Cr(VI), Cu, Mn, Ni, Pb, and Zn) health risks both for children and for adults were assessed using the United State Environmental Protection Agency (USEPA) methods considering inhalation, ingestion, and dermal contact pathway. Chromium (VI) posed the highest carcinogenic risk for both children and adults. The integrated carcinogenic risks were respectively 3.45 × 10⁻⁵ and 1.38 × 10⁻⁴ for children and adults indicating that attention should be paid for carcinogenic health effects. Nickel posed the highest non-carcinogenic risk for children through inhalation pathway. The integrated non-carcinogenic risk showed a value higher than 1 highlighting that Cd, Cr(VI), Cu, Mn, Ni, Pb, and Zn may cause cumulative non-carcinogenic health effect for children from inhalation exposure.
显示更多 [+] 显示较少 [-]An empirical evaluation of financial development-carbon footprint nexus in One Belt and Road region
2019
Hafeez, Muhammad | Yuan, Chunhui | Sānval, K̲h̲uram Shahzād | Aziz, Babar | Iqbal, Kashif | Raza, Salman
The aspiration of study is to explore the financial development-carbon footprint nexus in One Belt and Road initiative (BRI) region utilizing the panel dataset from 1990–2017. The cross-sectional dependence tests and second-generation panel unit tests were applied to affirm the cross-section dependence and integration level. The panel regression estimators from the Driscoll-Kraay standard error method for robust estimators in the presence of cross-sectional dependence have been applied to compute the estimators concerning the financial development-carbon footprint nexus for One Belt and Road economies. The estimates infer that financial development, urban population, and FDI have an adverse effect on carbon footprint. Furthermore, economic growth and energy consumption pollute the environment by enhancing the carbon footprint. Based on findings, it infers that financial development is a potential instrument to keep the environment through financial reforms. The estimates signify that it is necessary to allocate resources for renewable energy, energy efficiency, and energy conservation projects in order to moderate environmental degradation.
显示更多 [+] 显示较少 [-]Chemical composition of essential oils from four Rhododendron species and their repellent activity against three stored-product insects
2019
Bai, Li | Jiao, Mei-Ling | Zang, Hong-Yuan | Guo, Shan-Shan | Wang, Yang | Sang, Yu-Li | Du, Shu-Shan
The objective of this work was to analyze four essential oils (EOs) from Rhododendron species in China and evaluate their repellent activity against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila adults. These four EOs from Rhododendron species, including R. capitatum, R. przewalskii, R. mucronulatum, and R. micranthum, were obtained by hydrodistillation. Major components of four EOs were identified as sesquiterpenoids by GC-MS. The relatively high components included cedrene (22.20%), borneol (36.64%), 4-(2,3,4,6-tetramethylphenyl)-3-buten-2-one (27.74%), and germacrene D (27.60%). Repellent activity of EOs from Rhododendron species was investigated against T. castaneum, L. serricorne, and L. bostrychophila adults for the first time. In this study, EOs had demonstrated their repellent activities against three stored-product insects in 2- and 4-h exposure. The above results can not only provide comprehensive utilization of plant resources of Rhododendron genus but also establish a very good perspective of novel application to control stored-product insects.
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