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Preparation of high porosity biochar materials by template method: a review Texte intégral
2020
Xi, Jingen | Li, Hui | Xi, Jiamin | Tan, Shibei | Zheng, Jinlong | Tan, Zhongxin
Biochar plays an important role in soil improvement, pollutant removal, and nitrogen reduction. The excellent adsorption performance of biochar is closely related to its pore structure. Therefore, this paper combines a large amount of literatures to investigate the principle and method of preparing carbon materials by using the template method, and the idea of preparing high porosity biochar by template method was proposed. The results show that: (1) The specific surface area of the carbon materials prepared by the template method is more than 400 m² g⁻¹, and the total pore volume is more than 0.3 cm³ g⁻¹, which is much higher than the biochar materials prepared under the traditional high temperature anoxic pyrolysis. (2) Compared with the hard template method, a soft template method with simple operation, low toxicity of the compound, and low cost is selected. (3) The lignin, which is also a hydrophilic carbon source similar to phenolic resin, can be used as an ideal carbon precursor. (4) In the selection of templating agents, the specific surface area and total pore volume of carbon materials prepared by using F127 as a template are relatively large, showing more excellent pore size performance. (5) Finally, the idea of using template method to prepare high porosity biochar is proposed: lignin extracted from straw material is used as precursor, block polymer F127 is used as template, an appropriate amount of a cross-linking agent and a solvent is added, and finally the target biochar material is prepared by pyrolysis carbonization.
Afficher plus [+] Moins [-]Inflammatory effects of particulate matter air pollution Texte intégral
2020
Arias-Pérez, Rubén D. | Taborda, Natalia A. | Gómez, Diana M. | Narvaez, Jhon Fredy | Porras, Jazmín | Hernández, Juan C.
Air pollution is an important cause of non-communicable diseases globally with particulate matter (PM) as one of the main air pollutants. PM is composed of microscopic particles that contain a mixture of chemicals and biological elements that can be harmful to human health. The aerodynamic diameter of PM facilitates their deposition when inhaled. For instance, coarse PM having a diameter of < 10 μm is deposited mainly in the large conducting airways, but PM of < 2.5 μm can cross the alveolar-capillary barrier, traveling to other organs within the body. Epidemiological studies have shown the association between PM exposure and risk of disease, namely those of the respiratory system such as lung cancer, asthma, and chronic obstructive pulmonary disease (COPD). However, cardiovascular and neurological diseases have also been reported, including hypertension, atherosclerosis, acute myocardial infarction, stroke, loss of cognitive function, anxiety, and Parkinson’s and Alzheimer’s diseases. Inflammation is a common hallmark in the pathogenesis of many of these diseases associated with exposure to a variety of air pollutants, including PM. This review focuses on the main effects of PM on human health, with an emphasis on the role of inflammation.
Afficher plus [+] Moins [-]Comparative analysis on freshwater yield from conventional basin-type single slope solar still with cement-coated red bricks: an experimental approach Texte intégral
2020
Kabeel, Abd Elnaby | El-Agouz, El-Sayed | Athikesavan, Muthu Manokar | Duraisamy Ramalingam, Rajendran | Sathyamurthy, Ravishankar | Prakash, Nakka | Prasad, Chandran
This manuscript communicates the use of cement-coated red bricks for augmenting the production of distilled water using a traditional single slope solar still by low cost energy storage. The exposure area of water is increased in modified solar still (MSS) by keeping the cement-coated red bricks in the absorber. Using the energy storage material in the absorber, the water temperature was higher in the case of MSS at 20 kg water mass which was the minimum mass used during the experiment in the basin. From the results, it was also found that there is an improvement of about 34% in the temperature of water which acts as the driving force for evaporation of water inside the closed chamber. Furthermore, with increase in water temperature the productivity was enhanced by 45% as compared to the CSS. Comparison of different solar still on productivity was also analysed, and it is seen that the yield is higher in the present study by 38.8% than double slope-double basin solar still with different energy storage. The daily yield from CSS for water depth of 20, 30, 40 and 50 was found as 3.2, 2.8, 2.7 and 2.6 kg, whereas the modified solar still produced 6.3, 6, 5. 8 and 5.6 kg, respectively. Due to the reduced daily yield at higher water masses, the cost per litre of water produced from both conventional and modified solar still is higher.
Afficher plus [+] Moins [-]Si-Ca-K-Mg amendment reduces the phytoavailability and transfer of Cd from acidic soil to rice grain Texte intégral
2020
Wang, Yefeng | Ying, Yuqian | Lu, Shenggao
Cadmium (Cd) contamination in the soil-rice chain is the major threat to human health in China. It is very necessary to lower Cd phytoavailability in contaminated soils and reduce Cd transfer from soil to rice for food safety. This study applied the Si-Ca-K-Mg amendment (SCKM) to immobilize Cd in acidic soils and then reduce its accumulation in rice grain (Oryza sativa L.). Two agricultural soils (Alfisol and Ultisol) collected from Eastern China were treated with three levels of Cd concentration (0, 0.4, and 2.0 mg/kg), respectively, for pot experiment. The phytoavailability and chemical forms of Cd in two soils were determined using ethylenediaminetetraacetic acid (EDTA) and the European Community Bureau of Reference (BCR) extraction procedures. At 2.0 mg Cd/kg-treated soils, application of SCKM amendment increased the yield of rice grain by 10–17% for Alfisol and 14–39% for Ultisol, and reduced the concentrations of EDTA-extractable Cd by 6–27% for Alfisol and 5–25% for Ultisol, compared with treatment without amendment. SCKM amendment significantly (p < 0.05) reduced the bioconcentration factor (BCF) of Cd in root, straw, and grain of rice. Compared with treatment without amendment, the application of amendments decreased the Cd concentrations of rice grains by 35–76% for Alfisol and 31–72% for Ultisol, respectively. The BCR sequential extraction revealed that amendment reduced acid soluble Cd fraction by 6.2–13.6% for Alfisol and 6.1–13.5% for Ultisol, respectively, indicating that amendment could effectively transform the highly phytoavailable Cd into a more stable form. SCKM amendment addition significantly (p < 0.05) increased soil pH and exchangeable K⁺, and decreased exchangeable Al³⁺ contents in both soils. Our results demonstrated that SCKM amendment was effective in reducing the phytoavailability and transfer of Cd in soil-rice system, and ameliorating soil acidity. The SCKM amendment had greater potential as a low-cost and friendly environmentally amendment for safe production of rice in Cd-contaminated soils.
Afficher plus [+] Moins [-]Environmental cue affects the hearing-related behaviors of Drosophila melanogaster by targeting the redox pathways Texte intégral
2020
Dhar, Gyanaseni | Bag, Janmejaya | Mishra, Monalisa
Environmental cues like noise, pressure, and circadian rhythm can affect the hearing ability of human beings. Nevertheless, the complex physiology of the human being does not allow us to understand how these factors can affect hearing and hearing-related behaviors. Conversely, these effects can be easily checked using the hearing organ of Drosophila melanogaster, the Johnston organ. In the current study, the Drosophila was exposed to challenging environments like noise, low pressure, and altered circadian rhythm. The hearing organ of larvae, as well as adults, was analyzed for hearing-related defects. In the third instar larva, the cell deaths were detected in the antenna imaginal disc, the precursor of Johnston’s organ. Elevated levels of reactive oxygen species and antioxidant enzymes were also detected in the adult antennae of environmentally challenged flies. The ultrastructure of the antennae suggests the presence of abundant mitochondria in the scolopidia of control. Fewer amounts of mitochondria are found in the environmentally challenged adult antennae. In adults, various hearing-related behaviors were analyzed as a readout of functionality of the hearing organ. Analysis of climbing, aggressive, and courtship behaviors suggests abnormal behavior in environmentally challenged flies than the control. The current study suggests that the environmental cues can alter hearing-related behaviors in Drosophila. The methods used in this study can be used to monitor the environmental pollution or to study the effect of alteration of noise, pressure, and circadian rhythm on hearing-related behaviors taking Drosophila melanogaster as a model organism. Graphical abstract
Afficher plus [+] Moins [-]Developing the relationship between metal ionic characters and ecological risk assessment screening values using QICAR Texte intégral
2020
Li, Zhitao | Meng, Xiaoqi | Wang, Ying | Wang, Xuedong
Metals are widely released and distributed in soil and may have a negative impact on terrestrial organisms. Over the past years, a series of criteria or standards for assessing the ecological risks and toxicity of metals have been published in many countries; however, few studies have investigated their metal ionic properties and toxicity. In the present study, the ecological risk assessment screening values (ERASV) recommended by the Oregon Department of Environmental Quality were selected to investigate the correlation between metal toxicity and their ionic characters based on the hard and soft acids and bases (HSAB) concept. The results showed that more ionic characters were significantly correlated with ERASV using the HSAB theory, while only one metal ionic characteristic was correlated with ERASV in organisms. For borderline metal ions, maximum complex stability constants (log βn) and the softness (δp) of borderline ions were correlated with ERASV, while log βn and electronegativity (Xm) were significantly related to ERASV for borderline plus hard ions, and the boiling point (BP) and electron density (AR/AW) (AR indicates atomic radius and AW is atomic mass) were significantly related to ERASV for borderline plus soft ions. These results indicated that different metal ion characteristics play different roles in different types of metal toxicity in organisms and the mechanisms of toxicity are different. Based on these relationships, a set of quantitative ion characteristic parameter-activity relationship (QICAR) was developed. The QICAR predicted ERASV for metals that were reasonably consistent with those recommended by the Oregon Department of Environmental Quality, with differences between them generally < 2.0 orders of magnitude. However, there were discrepancies between the recommended and predicted values, and these discrepancies may be related to terrestrial geochemical properties. These soil properties should be further considered when developing QICAR models in future studies, such as soil type, organic matter, and pH. Overall, the QICAR models were able to determine the relationships between metal ionic properties and their toxicity and will be useful for assessing toxicity data on unknown toxic metals and will provide a basis for ecological assessment.
Afficher plus [+] Moins [-]Adsorption and reduction of Cr(VI) by hydroxylated multiwalled carbon nanotubes: effects of humic acid and surfactants Texte intégral
2020
Huang, Yu | Song, Ke | Luo, Wei | Yang, Jiewen
The present study investigated the impacts of humic acid (HA) and surfactants (SDBS and CTAB), which were ubiquitously found in the aquatic environments, on the removal of Cr(VI) by the hydroxylated MWCNTs-OH. The results showed that MWCNTs-OH could remove Cr(VI) from aqueous solution via adsorption coupled with reduction, and the kinetics followed the pseudo-first-order model with the rate of 3.5 × 10⁻³ h⁻¹. In the presence of anionic SDBS, the removal percentage of Cr(VI) was greatly inhibited because the hydrophobic interaction and π-π interaction between SDBS and MWCNTs-OH surfaces not only decreased the adsorption sites for Cr(VI) but also made the surfaces more negatively charged. On the contrary, the existence of cationic CTAB could lead to the surfaces more positively charged, which consequently enhance the electrostatic attraction between Cr(VI) and the surfaces as well as the removal of Cr(VI). Noticeably, the presence of HA could promote the removal of Cr(VI), which was attributed to the reduction of Cr(VI) by the adsorbed HA. The ESR spectra indicated the existence of π-type radicals in HA structure and conduction electrons in MWCNTs-OH, and then the π-π interaction between MWCNTs-OH and adsorbed HA possibly increase the electron-donating ability of HA. Moreover, the promotive effect of HA could be enhanced with the addition of Ca²⁺. This study was helpful for us to understand the role of MWCNTs-OH in controlling the fate of Cr(VI) when HA and surfactants were present.
Afficher plus [+] Moins [-]A new simple protocol for the synthesis of nanohybrid catalyst for oxidative desulfurization of dibenzothiophene Texte intégral
2020
Ghahramaninezhad, Mahboube | Ahmadpour, Ali
This study offers an investigation of the catalytic activity of TiO₂/SiO₂ during oxidative desulfurization (ODS) of a model fuel that includes dibenzothiophene (DBT), using hydrogen peroxide (H₂O₂) as a green oxidant in the absence of UV irradiation. For the first time, though a novel and simple protocol, TiO₂/SiO₂ nanohybrid was synthesized using ascorbic acid and glycerol as green complexing and polymerizing agents, respectively. The TiO₂/SiO₂ catalyst was thoroughly characterized by XRD, FT-IR, nitrogen adsorption-desorption measurements, TEM, FESEM, and TGA. Results revealed a high catalytic oxidative activity for the catalyst in the removal of DBT regarding sulfur removal up to 99.4% within 20 min under optimum reaction conditions. The main factors affecting the ODS process, including catalyst dosage, temperature, O/S molar ratio, and different oxidizing agents, were evaluated to identify optimum conditions. The desulfurization efficiency of the recoverable catalysts showed no loss in activity after four times. The present article suggests a new and green method for the synthesis and characterization of an efficient catalyst (TiO₂/SiO₂) in deep oxidative desulfurization at 25 °C and removal of refractory organosulfur compounds that yield ultra-low sulfur fuels. Also, it proved to have a much higher catalytic oxidation capacity when compared to pure TiO₂.
Afficher plus [+] Moins [-]Elevated exposure to polycyclic aromatic hydrocarbons (PAHs) may trigger cancers in Pakistan: an environmental, occupational, and genetic perspective Texte intégral
2020
Rehman, Muhammad Yasir Abdur | Taqi, Malik Mumtaz | Hucheina, Imarāna | Nasir, Jawad | Rizvi, Syed Hussain Haider | Syed, Jabir Hussain
Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic compounds which are emitted through incomplete combustion of organic materials, fossil fuels, consumption of processed meat, smoked food, and from various industrial activities. High molecular mass and mobility make PAHs widespread and lethal for human health. A cellular system in human detoxifies these toxicants through specialized enzymatic machinery called xenobiotic-metabolizing (CYP450) and phase-II (GSTs) enzymes (XMEs). These metabolizing enzymes include cytochromes P450 family (CYP1, CYP2), glutathione s-transferases, and ALDHs. Gene polymorphisms in XMEs encoding genes can compromise their metabolizing capacity to detoxify ingested carcinogens (PAHs etc.) that may lead to prolong and elevated exposure to ingested toxicants and may consequently lead to cancer. Moreover, PAHs can induce cancer through reprograming XMEs’ gene functions by altering their epigenetic markers. This review article discusses possible interplay between individual’s gene polymorphism in XMEs’ genes, their altered epigenetic markers, and exposure to PAHs in cancer susceptibility in Pakistan.
Afficher plus [+] Moins [-]The nexus between economic globalization and human development in Asian countries: an empirical investigation Texte intégral
2020
Ulucak, Recep | Danish, | Li, Nan
In recent years, countries both developed and developing ones have experienced a rapid economic globalization expanding economic activities. Although this economic globalization process is fruitful for the economy; however, what role it plays in the promotion of the human development index is still unknown. To this end, the study tries to explore the linkage among economic globalization, real income, and human development index in Asian countries from 1990 to 2015. The advanced econometric techniques that allow dependencies across countries are employed. The panel cointegration approach, Westerlund (2007) panel cointegration test, confirms the cointegration relationship among study variables, and the study estimates long-run cointegration parameters. Results reveal that economic globalization has not a significant impact on human development. However, real income promotes human development in Asian countries.
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