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Promotional effect of Mn modification on DeNOx performance of Fe/nickel foam catalyst at low temperature
2019
Zi, Zhaohui | Zhu, Baozhong | Sun, Yunlan | Fang, Qilong | Ge, Tingting
Manganese (Mn)-modified ferric oxide/nickel foam (Fe/Ni) catalysts were prepared using Ni as a carrier, Fe and Mn as active components to study NH₃–SCR of NOₓ at low temperature. The effects of different Fe loads and Mn-modified Fe/Ni catalysts on the DeNOₓ activity were investigated. Results show that when the amount of Fe is 10%, Fe/Ni catalyst has the highest NOₓ conversion. For the Mn-modified Fe/Ni catalysts, the NOₓ conversions firstly increase and then decrease with the Mn loading amount increasing. 3MnFe/Ni catalyst shows high NOₓ conversions, which reach 98.4–100% at 120–240 °C. The characterization analyses reveal that Mn-modified Fe/Ni catalysts increase the FeOₓ dispersion on Ni surface, improve significantly the valence ratio of the Fe³⁺/Fe²⁺, the content of lattice oxygen which promotes the catalyst storage and exchange oxygen capacity at low temperature, and the number of Brønsted active acid sites on the catalyst surface, and enhance the low-temperature redox capacity. These factors remarkably increase the NOₓ conversions at low temperature. Especially, 3Mn10Fe/Ni catalyst not only has excellent DeNOₓ activity but also has better water resistance. However, the anti-SO₂ poisoning performance needs to be improved. To further analyze the reason why different catalysts show different DeNOₓ performance, the reaction kinetics was also explored.
Show more [+] Less [-]Modelling aggregate exposure to pesticides from dietary and crop spray sources in UK residents
2019
Kennedy, Marc C. | Garthwaite, David G. | de Boer, Waldo J. | Kruisselbrink, Johannes W.
Human exposure to pesticide mixtures can occur from the diet and other sources. Realistic exposure and risk assessments should include multiple sources and compounds and include the relative hazards of the different compounds. The EU-funded Euromix project is developing new web-based tools to facilitate these calculations. A case study is presented that exemplifies their use for a population of UK residents, including exposure from crop-spraying. A UK pesticide usage survey provided information on real pesticide combinations applied to crops of wheat, potatoes, sugar beet and dessert apples. This information was combined with outputs from two alternative simulation models of spray drift to estimate dermal, oral and inhalation exposures of residents. These non-dietary exposures were combined with dietary exposure estimates using the Monte Carlo Risk Assessment software to produce a distribution of aggregated and cumulative exposures. Compounds are weighted by relative potency to generate a measure of overall risk. Uncertainty quantification was also included in the distribution of exposures. These tools are flexible to allow diverse sources of exposure and can provide important information to decision-makers and help to prioritise testing of pesticide mixtures. Including non-dietary sources changed the prioritisation of pesticide mixtures, when compared to dietary exposure alone.
Show more [+] Less [-]Human health damages related to air pollution in China
2019
Gu, Hejun | Cao, Yuxia | Elahi, Ehsan | Jha, Sunil Kumar
In recent years, air pollution in China has posed serious threats to human health. In this study, we investigate the relationship between air pollution and residents’ health by nesting the household registration data of the China Migrant Dynamic Survey in 2014 with city characteristic data and pollution data. The results indicated that an increase in the concentration of air pollution significantly reduced residents’ health levels. After using the instrumental variable (IV)-Oprobit model to solve endogenous problem, we have found that the negative impact of air pollution on residents’ health remained significant. Moreover, the lag term of environmental indexes was introduced and found that air pollution significantly increased health risk. The results also demonstrated that the impact of air pollution on human health was heterogeneous. Men and urban residents were more sensitive to air pollution and more adversely affected. In addition to air pollution, the study found that, among the influencing factors at the individual level, males’ health was better than females’ health, and education positively impacted on residents’ health. The health effects were consistent with the theoretical predictions of the Grossman model. The financial expenditure and medical input were negatively correlated with residents’ health levels. Based on the results, we suggest the Chinese government should implement rigorous air pollution laws and regulations.
Show more [+] Less [-]Use of spent coffee ground biochar as ambient PAHs sorbent and novel extraction method for GC-MS analysis
2019
Tala, Wittaya | Chantara, Somporn
In recent years, biochar has received a significant amount of attention for its potential beneficial applications in various fields due to its bio-physico-chemical properties. The spent coffee ground biochar was prepared by slow pyrolysis for adsorption of 16-polycyclic aromatic hydrocarbons (PAHs) in ambient air. New materials and extraction methods were developed for PAHs analysis, particularly for low molecular weight (2–4 rings) PAHs, which are likely to evaporate at room temperature. Production and characterization of biochar and its extraction parameters after PAHs adsorption were investigated and optimized. The biochar production at 500 °C provided adequate quality for PAHs adsorption with a 35% yield. An effective clean-up method for biochar was proposed. A new method of PAHs extraction from biochar was developed using 25 mL of a mixture of dichloromethane and 2-propanol (4:1) for 30 min at low temperatures (5–10 °C). A test on the efficiency of the extraction method was carried out and recoveries of 85–104% of PAHs were obtained. The lab-made biochar was also tested for its potential in ambient PAHs sampling and compared with a commercial sorbent (XAD-2). The results revealed that almost the same concentrations of ambient PAHs (ng/m³) were absorbed by both sorbent types, particularly with regard to the 4 ring-PAHs.
Show more [+] Less [-]The potential of Mikania micrantha (Chinese creeper) to hyperaccumulate heavy metals in soil contaminated by electronic waste
2019
Leung, Ho Man | Yue, Patrick Ying Kit | Sze, Stephen Cho Wing | Au, Chi Kin | Cheung, Kwai Chung | Chan, Ka Loi | Yung, Kin Lam Ken | Li, Wai Chin
The objective of this study is to investigate the contributions of Mikania micrantha (chinese creeper) to remediate heavy metal pollutants present in an e-waste-contaminated soil. Different proportions of e-waste soil (0%, 25%, 50%, 75%, and 100% w/w) planted with Cynodon dactylon together with the test species were prepared for testing relative seed germination (RSG), relative root growth (RRG), and germination index (GI) tests. A significant higher value of GI (77.8%) was found in M. micrantha than that of the other species when planting in 100% e-waste-contaminated soil. A significant correlation (< 0.05) was found between heavy metal concentration and germination assays in M. micrantha. A significant decrease in heavy metal concentration of the polluted soil after the experiment indicated that biomolecule development studies to determine the aggregate benefit of M. micrantha for phytoremediation remain to be studied in future.
Show more [+] Less [-]The nephroprotective effects of allicin and ascorbic acid against cisplatin-induced toxicity in rats
2019
Abdel-Daim, Mohamed M. | Abushouk, Abdelrahman Ibrahim | Donia, Thoria | Alarifi, Saud | Alkahtani, Saad | Aleya, Lotfi | Bungau, Simona G.
Cisplatin (CDDP) may induce nephrotoxicity through oxidative stress, DNA damage, and inflammation. This study was performed to evaluate the antioxidant and anti-inflammatory effects of allicin and ascorbic acid (AA) and investigate the nephroprotective efficacy of their combination against CDDP-induced intoxication. Rats were divided into seven groups: control, allicin (10 mg/kg for 14 days), AA (20 mg/kg for 14 days), CDDP (7 mg/kg as a single dose on the seventh experimental day), CDDP-allicin, CDDP-AA, and CDDP-allicin-AA (at the aforementioned doses). The administration of CDDP induced marked body weight loss and renal damage, manifested by significant increases (p < 0.05) in serum creatinine, urea, and uric acid levels and significant reductions in serum Na, Ca, and phosphorus concentrations, in addition to severe alterations in serum and renal tissue levels of tumor necrosis factor-α in comparison with control rats. Moreover, CDDP-intoxicated rats exhibited significantly (p < 0.05) higher lipid peroxidation, as well as lower levels of reduced glutathione and activities of glutathione peroxidase, superoxide dismutase, and catalase enzymes in the renal tissue, compared with control rats. The administration of allicin or AA significantly reduced (p < 0.05) the CDDP-induced changes in all the aforementioned parameters. Interestingly, allicin achieved comparable nephroprotection to AA in most assessed parameters; however, the restoration of normal serum and renal tissue concentrations of these parameters was more frequent in the CDDP-AA group. In conclusion, both allicin and AA showed significant nephroprotective effects against CDDP intoxication and their combination exhibited better protection than either agent alone. These results are probably mediated by their antioxidant and anti-inflammatory activities.
Show more [+] Less [-]Monte Carlo fingerprinting of the terrestrial sources of different particle size fractions of coastal sediment deposits using geochemical tracers: some lessons for the user community
2019
Gholami, Hamid | Jafari TakhtiNajad, Ebrahim | Collins, Adrian L. | Fathabadi, Aboalhasan
A sediment source fingerprinting method, including a Monte Carlo simulation framework, was used to quantify the contributions of terrestrial sources of fine- (< 63 μm) and coarse-grained (63–500 μm) sediments sampled from three categories of coastal sediment deposits in the Jagin catchment, south-east of Jask, Hormozgan province, southern Iran: coastal dunes (CD), terrestrial sand dunes or onshore sediments (TSD), and marine or offshore sediments (MD). Forty-nine geochemical properties were measured in the two size fractions and a three-stage statistical process consisting of a conservation test, the Kruskal–Wallis H test, and stepwise discriminant function analysis (DFA) was applied to select final composite fingerprints for terrestrial source discrimination. Based on the statistical tests, four final fingerprints comprising Be, Ni, K and Cu and seven final fingerprints consisting Cu, Th, Be, Al, La, Mg and Fe were selected for discriminating terrestrial sources of the coastal fine- and coarse-grained sediments, respectively. Two geological spatial sources, including Quaternary (clay flat, high and low level fans and valley terraces) and Palaeocene age deposits, were identified as the main terrestrial sources of the fine-grained sediment sampled from the coastal deposits. A geological spatial source consisting of sandstone with siltstone, mudstone and minor conglomerate (Palaeocene age deposits) was identified as the main terrestrial source for coarse-grained sediment sampled from the coastal deposits.
Show more [+] Less [-]Multi-core-shell composite SnO2NPs@ZIF-8: potential antiviral agent and effective photocatalyst for waste-water treatment
2019
Chandra, Ramesh | Singh, Vedita | Tomar, Shailly | Nath, Mala
With increasing environment pollution and bacterial transmitted viral diseases globally, the development of new, effective, and low-cost materials/strategies is the current major challenge. To combat with this alarming problem, three new multi-functional and thermally stable SnO₂NPs@ZIF-8 composites (NC1, NC2, and NC3) were synthesized by a facile and sustainable approach involving in situ encapsulation of SnO₂NPs (150, 300, and 500 μL suspension in methanol) within zeolitic imidazole framework at room temperature. The morphology and crystallinity of ZIF-8 remained unchanged upon the proper encapsulation of SnO₂NPs in its matrix. Herein, for the first time, the antiviral potential of ZIF-8 and SnO₂NPs@ZIF-8 against chikungunya virus is reported by investigating their cytotoxicity against Vero cell line (employing MTT ((3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide)) assay). The maximum non-toxic doses were 0.04 mg mL⁻¹ for ZIF-8 and SnO₂NPs@ZIF-8 and 0.1 mg mL⁻¹ for SnO₂NPs. Further, NC1 exhibited (based on plaque assay) reduction in viral load/titers up to > 80% during post-treatment and > 50% during pre-treatment, greater than that of ZIF-8 and SnO₂NPs due to synergistic effect. Further, NC1 (10 mg) exhibited enhanced photocatalytic efficiency (≥ 96%) for degradation of methylene blue (0.5 × 10⁻⁵ M) at pH ˃ 7.0. The probable mechanism for their antiviral activity and photocatalytic activity has been discussed. The multi-functional composites can effectively be used to reduce water pollution and as remedy for mosquito/bacterial transmitted viral diseases.
Show more [+] Less [-]Potential application of oil-suspended particulate matter aggregates (OSA) on the remediation of reflective beaches impacted by petroleum: a mesocosm simulation
2019
Silva, Carine S. | de Oliveira, Olivia M. C. | Moreira, Icaro T. A. | Queiroz, Antonio F. S. | de Almeida, Marcos | Silva, Jessica V. L. | da Silva Andrade, Igor Oliveira
This paper presents the oil-suspended particulate matter aggregate (OSA) resulted from the interaction of droplets of dispersed oil in a water column and particulate matter. This structure reduces the adhesion of oil on solid surfaces, promotes dispersion, and may accelerate degradation processes. The effects of the addition of fine sediments (clay + silt) on the formation of OSA, their impact on the dispersion and degradation of the oil, and their potential use in recovering reflective sandy beaches were evaluated in a mesoscale simulation model. Two simulations were performed (21 days), in the absence and presence of fine sediments, with four units in each simulation using oil from the Recôncavo Basin. The results showed that the use of fine sediment increased the dispersion of the oil in the water column up to four times in relation to the sandy sediment. There was no evidence of the transport of hydrocarbons in bottom sediments associated with fine sediments that would have accelerated the dispersion and degradation rates of the oil. Most of the OSA that formed in this process remained in the water column, where the degradation processes were more effective. Over the 21 days of simulation, we observed a 40 % reduction on average of the levels of saturated hydrocarbons staining the surface oil.
Show more [+] Less [-]Eichhornia crassipes biodiesel as a renewable green fuel for diesel engine applications: performance, combustion, and emission characteristics
2019
Venu, Harish | Venkataraman, Dhinakaran | Purushothaman, Prince | Vallapudi, Dhana Raju
This work examines the feasibility of fuelling biodiesel derived from Eichhornia crassipes in a compression ignition engine. This work also proposes water hyacinth biodiesel (WHB) as a potential alternative energy source since the above species is available extensively in freshwater, marine, and aquatic ecosystems throughout the world. WHB was blended with petroleum diesel fuel at various volume proportions of 10%, 20%, 30%, 40%, and 100% and their properties were analyzed as per ASTM standards for its application as biofuel. The prepared test fuels were analyzed experimentally in a single-cylinder diesel engine at constant speed (1500 rev/min) for its performance, combustion, and emission characteristics. Test results projected that the characteristics of 20% WHB + 80% diesel fuel blend were in par with neat diesel fuel in terms of thermal efficiency, HC, CO, and smoke emissions. However, WHB blends resulted in slightly higher levels of CO₂ and NOx emissions. At full load, the attained cylinder pressure and heat release rate of WHB were comparatively lower than diesel fuel. Ignition delay is lowest for B100 blend and therefore the diffusion burning phase of biodiesel phase is found to be dominant in comparison with diesel fuel. For biodiesel blends, the combustion starts earlier due to higher cetane number, lessened delay period, and lowered calorific value followed by lowered HRR. Graphical abstract
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