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Hybrid multifunctional core/shell g-C3N4@TiO2 heterojunction nano-catalytic for photodegradation of organic dye and pharmaceutical compounds 全文
2021
Hussien, Mai S. A. | Yahia, Ibrahim S.
The pyrolysis of melamine was an effective one-pot method for preparing a nanostructured multifunctional photocatalytic based on core/shell g-C₃N₄@TiO₂ heterojunction. Various techniques entirely characterized these materials: X-ray diffraction (XRD) proved to enhance the as-prepared materials’ crystallinity through the variation of dislocation, strain, and crystallite size with TiO₂ loading. The stacked layered/sheet-like with a smooth surface of the as-prepared samples have been shown via scanning electron microscopy (SEM). Diffuse reflectance spectroscopy (DRS) showed an apparent decrease in the energy bandgap for these nanocomposites with TiO₂ loading. All the prepared materials were subjected to visible photocatalytic applications under the same conditions. The dye model (Methylene Blue, MB), and antibiotic model (Amoxicillin, AMO), was photodegraded using the as-prepared nanocomposites under visible light irradiation. In the recombination reduction among TiO₂ and g-C₃N₄ interfaces, g-C₃N₄ has been effectively utilized as a matrix. Our findings proved that g-C₃N₄@TiO₂ photocatalysts exhibited superior photocatalytic performance. CNT-5 of 2.58 eV bandgap had a higher activity of 99.7 in 50 min for MB and 100% in 20 min for AMO than the other represented photocatalysts in this work. The migration of photogenerated electrons from a g-C₃N₄ to TiO₂ via heterojunction among them as g-C₃N₄ (1 0 1) removes the electrons accumulated on (1 0 1) of TiO₂, improve the photodegradation efficiency. Therefore, the increase in photocatalytic reaction rates, recycling, and the sample’s photostability can be considered the result of successful interactions among the TiO₂ and g-C₃N₄ systems. The suggested photodegradation mechanism of MB and AMO was discussed in detail and compared with previously reported work. Therefore, the photodegradation rate of MB and AMO via CNT-5 composite is 6 and 3 times, respectively, higher than that of g-C₃N₄ under simulated solar irradiation. This research creates a new perspective on the production of nanocomposite materials in the area of treatment of pharmaceutical and dye contaminants.
显示更多 [+] 显示较少 [-]Impact of the increasing concentrations of selected perfluoroalkyl acids on the observed concentrations of red blood cell folate among US adults aged ≥20 years 全文
2021
Jain, Ram B.
For the first time (N = 6291), a study was undertaken to estimate associations between the concentratio ns of red blood cell folate (RBCF) and concentration of six perfluoroalkyl acids (PFAAs), namely, perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorodecanoic acid (PFDA), perfluorononanoic acid (PFNA), and perfluoroundecanoic acid (PFUnDA) for US adults aged ≥20 years by fitting regression models for the data from National Health and Nutrition Examination Survey for 2007–2014. In almost consistent fashion, increasing concentrations of PFAAs were associated with decreasing concentrations of RBCF. For the total population, for a 10% increase in the concentrations of PFOA, PFOS, PFDA, PFHxS, PFNA, and PFUnDA, percent decreases in RBCF concentrations were found to be 0.33%, 0.66%, 0.83%, 0.16%, 0.89%, and 0.43%, respectively. RBCF concentrations of PFAAs were found to be 1104, 1042, 100, and 936 nmol/L across the four quartiles of PFOS; 112, 1068, 1009, and 948 nmol/L across the four quartiles of PFDA; 1125, 1054, 1005, and 967 nmol/L across the four quartiles of PFNA; and 1099, 1094, 989, and 952 nmol/L across the four quartiles of PFUnDA. Perfluorinated carboxylic acids with carbon chain length > 8 decreased concentrations of RBCF to a greater degree than those carbon chain length ≤ 8. Perfluorinated chemicals with a sulfonic group with carbon chain length > 6 decreased concentrations of RBCF to a greater degree than those carbon chain length ≤ 6. The degree to which concentrations of RBCF decrease varied by age, gender, and race/ethnicity. Non-Hispanic blacks as compared to non-Hispanic whites and Hispanics had the lowest decreases in RBCF concentrations. Mechanisms responsible for negative associations between RBCF and PFAA concentrations are not known and will need to be researched further.
显示更多 [+] 显示较少 [-]Optimization of energy systems using the concept of balance in the nature 全文
2021
Hajabdollahi, Hassan | Shafiey Dehaj, Mohammad
In this paper, a concept of balance is used to improve the important parameters of the thermal systems. In fact, using this concept give the designer to propose some new configuration which is more efficient. To show the benefit of this concept, firstly, the proposed balancing method is introduced for a simple case study after that its application is used in optimization of thermal systems. In this regard, to achieve the better optimal results in each problem, the unbalanced factors are detected and some solutions are presented to reduce the system unbalancing. Three case studies including Rankine cycle, plate fin heat exchanger, and double pipe heat exchanger are discussed and optimized to show the benefits of this method.
显示更多 [+] 显示较少 [-]Pesticide and trace element bioaccumulation in wild owls in Brazil 全文
2021
Dal Pizzol, Gabriela Elisa | Rosano, Vitória Aquino | Rezende, Elinton | Kilpp, Jonas Claudiomar | Ferretto, Marcelo Menezes | Mistura, Enzo | da Silva, Arthur Nery | Bertol, Charise Dallazem | Rodrigues, Laura Beatriz | Friedrich, Maria Tereza | Rossato-Grando, Luciana Grazziotin
Owls are outstanding environmental quality bioindicators due to their position at the top of the food chain and susceptibility to pollutant accumulation. Exposure to chemical contaminants is often a risk for these animals. Moreover, studies addressing the bioaccumulation of trace elements and pesticide residues in tropical nocturnal raptor species are scarce. We analyzed the 26 organs (heart, liver, and kidney) of Tyto furcata (n=3), Megascops spp. (n=5), Pulsatrix koeniswaldiana (n=1), and Asio stygius (n=1) carcasses, collected from June 2018 to May 2019 in the Southern region of Brazil. The original vegetation consisted of areas of Araucaria forests and grassy-woody steppes with gallery forests, which were greatly modified by the introduction of agriculture. In four animals and eight organs, the pesticides abamectin, atrazine, chlorpyrifos-ethyl, and diurom were analyzed through high-performance liquid chromatography coupled with a mass detector. In six animals and eighteen organs, the trace elements cadmium, lead, chromium, and nickel were identified via atomic absorption spectrophotometry. Chlorpyrifos-ethyl was detected in the livers of the genus Megascops. Chromium was found at high concentrations in all matrices analyzed for this trace element. Moreover, P. koeniswaldiana presented lead levels indicative of high exposure. The bioaccumulation of these toxics in owls described here can impact the population levels of these species, impact on its ecological function, and consequently unbalance the ecosystem. Moreover, owls are considered bioindicators; therefore, the occurrence of bioaccumulation indirectly gives us information about the quality of the environment.
显示更多 [+] 显示较少 [-]Fate and Behaviour of TiO2 Nanoparticles in the Soil: Their Impact on Staple Food Crops 全文
2021
Thiagarajan, Vignesh | Ramasubbu, Seenivasan
In the agroecosystem, titanium dioxide nanoparticles are used in fertilisers, pesticides, remediation and bio-sensors. These applications lead to a pervasive and inevitable distribution of TiO₂ NPs in the agroecosystem. It is very important to understand the behaviour of TiO₂ NPs in the soil and to assess their impact on the agroecosystem. This review aims to provide an overview of the fate and behaviour of TiO₂ NPs in the soil and their impact on staple food crops. The first part of this review deals with the application, and release of TiO₂ NPs followed by their fate and behaviour of TiO₂ NPs in the soil. Furthermore, the dual (beneficial and toxic) impact of TiO₂ NPs on staple food crops such as wheat, rice and maize has been discussed. We also address the mechanism of impact of TiO₂ NPs. The second part deals with the beneficial impact of TiO₂ NPs followed by their critical assessment. The final section of the review deals with the existing knowledge gaps and future research directions. This review is to deliver information on the safer application of nanoparticles in agriculture.
显示更多 [+] 显示较少 [-]Matlodextrin-cinnamon essential oil nanoformulation as a potent protective against titanium nanoparticles-induced oxidative stress, genotoxicity, and reproductive disturbances in male mice 全文
2021
Salman, Asmaa S. | Al-Shaikh, Turki M. | Hamza, Zeinab K. | El-Nekeety, Aziza A. | Bawazir, Salwa S. | Hassan, Nabila S. | Abdel-Wahhab, Mosaad A.
Recently, bio-nanofabrication becomes one of the widest methods for synthesizing nanoparticles (NPs); however, there is scanty literature exploring the toxicity of these green NPs against living organisms. This study aimed to evaluate the potential protective role of encapsulated cinnamon oil (ECO) against titanium oxide nanoparticle (TiO₂NP)–induced oxidative stress, DNA damage, chromosomal aberration, and reproductive disturbances in male mice. Sixty male Balb/c mice were distributed into six groups treated orally for 3 weeks and included control group, TiO₂NP-treated group (25 mg/kg b.w), ECO at low or high dose–treated groups (50 or 100 mg/kg b.w), and the groups that received TiO₂NPs plus ECO at a low or high dose. The results of GC-MS revealed the isolation of 21 compounds and the majority was cinnamaldehyde. The average size zeta potential of TiO₂NPs and ECO were 28.9 and 321 nm and −33.97 and −17.35 mV, respectively. TiO₂NP administration induced significant changes in liver and kidney function, decreased antioxidant capacity, and increased oxidative stress markers in liver and kidney, DNA damage in the hepatocytes, the number of chromosomal aberrations in the bone marrow and germ cells, and sperm abnormalities along with histological changes in the liver, kidney, and testis. Co-administration of TiO₂NPs and ECO could alleviate these disturbances in a dose-dependent manner. It could be concluded that ECO is a promising and safe candidate for the protection against the health hazards of TiO₂NPs.
显示更多 [+] 显示较少 [-]Pb(II) Adsorption on Eastern Spruce Sawdust (Turkey) by Applying Taguchi Method and Adsorption Isotherms 全文
2021
Bilgin, Ayla | Ateş, Esra
Modern industry advances through time with the change in living conditions as more chemicals are used and released into the environment. This causes severe pollution problems, especially of heavy metals including lead (Pb(II)). Pb(II) is continuously released by different industries into the environment, and it leads to certain diseases such as anemia and kidney malfunction. This study examines the adsorption of Pb(II) from aqueous solution regarding eastern spruce sawdust (Picea orientalis) in Turkey, and SEM/EDS and FTIR analyses were applied to determine the chemical structure of Picea orientalis. Moreover, the Taguchi method was utilized to investigate the effects of initial metal ion concentration and contact time on Pb(II) removal. It was found that initial metal concentration has more impact on Pb(II) removal than contact time. The condition of 626 mg/L and 60 min by using 0.3 g sawdust usage was found to be the optimum setting for Pb(II) adsorption. Furthermore, the behavior of Pb(II) adsorption was examined by using Langmuir and Freundlich isotherms. The adsorption occurred not only on the monolayer but also on heterogeneous surfaces due to the R² values close to 1.
显示更多 [+] 显示较少 [-]Nitrogen Recovery from Clear-Cut Forest Runoff Using Biochar: Adsorption–Desorption Dynamics Affected by Water Nitrogen Concentration 全文
2021
Kakaei Lafdani, E. | Laurén, Ari | Cvetkovic, Jovana | Pumpanen, Jukka | Saarela, Taija | Palviainen, Marjo
Forest regeneration operations increase the concentration of nitrogen (N) in watercourses especially outside the growing season when traditional biological water protection methods are inefficient. Biochar adsorption-based water treatment could be a solution for nutrient retention. We studied the total nitrogen (TN) and nitrate–nitrogen (NO₃⁻–N) adsorption–desorption properties of spruce and birch biochar. The adsorption test was performed under four different initial concentrations of TN (1, 2, 3, and 4 mg L⁻¹) using forest runoff water collected from ditch drains of boreal harvested peatland. The results showed that the TN adsorption amount increased linearly from the lowest to the highest concentration. The maximum adsorption capacity was 2.4 and 3.2 times greater in the highest concentration (4 mg L⁻¹) compared to the lowest concentration (1 mg L⁻¹) in spruce and birch biochar, respectively. The NO₃⁻–N adsorption amount of birch biochar increased linearly from 0 to 0.15 mg NO₃⁻–N g biochar⁻¹ when the initial concentration of NO₃⁻–N increased from 0.2 to 1.4 mg L⁻¹. However, in spruce biochar, the initial concentration did not affect NO₃⁻–N adsorption amount. The results indicate that concentration significantly affects the biochar’s capacity to adsorb N from water. The desorption test was performed by adding biochar extracted from the adsorption test into the forest runoff water with low TN concentration (0.2 or 0.35 mg L⁻¹). The desorption results showed that desorption was negligibly small, and it was dependent on the TN concentration for birch biochar. Therefore, biochar can be a complementary method supporting water purification in peatland areas.
显示更多 [+] 显示较少 [-]Abscisic acid modulates differential physiological and biochemical responses of roots, stems, and leaves in mung bean seedlings to cadmium stress 全文
2021
Leng, Yan | Li, Yi | Ma, Yan-Hua | He, Li-Fang | Li, Shi-Weng
Experiments were conducted to determine how exogenous abscisic acid (ABA) mediates the tolerance of plants to cadmium (Cd) exposure. Cd stress strongly reduced all the growth parameters of mung bean seedlings. Cd significantly increased ascorbate peroxidase (APX) and catalase (CAT) activities in roots and stems, and peroxidase (POD) activities in roots, stems, and leaves of mung bean seedlings. Cd caused remarkable increases in the levels of leaf chlorophyll and carotenoid, root polyphenols, and malondialdehyde (MDA) and proline in the three organs. However, Cd greatly decreased leaf CAT activity, root and leaf ascorbic acid (AsA) levels, and stem and leaf polyphenol levels. Foliar application of ABA partially alleviated Cd toxicity on the seedlings. ABA could restore most of the changed biochemical parameters caused by Cd, suggesting that ABA played roles in the protection of membrane lipid peroxidation and the modulation of antioxidative defense systems in response to Cd stress. Our results also implied the differential physiological and biochemical responsive patterns of roots, stems, and leaves to Cd and ABA in mung bean seedlings. The great changes in many biochemical parameters in roots suggested that roots were the first to be affected by Cd and play pivotal roles in response to Cd, especially in chelating Cd and reducing Cd absorption.
显示更多 [+] 显示较少 [-]The nexus between renewable energy consumption and economic growth in Morocco 全文
2021
Bouyghrissi, Soufiane | Berjaoui, Abdelmoumen | Khanniba, Maha
It is known that the transition to renewable energy can be a lever for the growth of both developed and developing countries. Thus, the whole world starts to become aware of the importance of the development of renewable energies, which became a priority for the future. In this context, Morocco belongs to the countries that set up some development policies for renewable energies in the short and medium term. Furthermore, this article investigates and analyzes the nexus and the relationship between renewable and non-renewable energy consumption, CO₂ emissions, and economic growth for Morocco over the period going from 1990 to 2014 using the auto-regressive distributed lag model approach and the Granger causality test. The empirical results support that renewable energies in Morocco start to give their positive effects on the economic dimension of sustainable development and it is found that there is causality from renewable energy consumption to economic growth and from economic growth to CO₂ emissions. However, the Moroccan government and private companies must look for innovative methods to finance renewable energy projects. In addition, these technologies can be the best substitute for fossil fuels: firstly, in order to reduce the burden of energy costs on the Moroccan economy (the energy bill in Morocco continues to rise, more than 100 billion DH in 2012); secondly, to strengthen its competitiveness without affecting the economic growth of the country.
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