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Biosorption of tungstate onto garlic peel loaded with Fe(III), Ce(III), and Ti(IV) Full text
2020
Wang, Yaoyao | Huang, Kai
In present study, garlic peel (GP) was modified by loading with Fe(III), Ti(IV), and Ce(III) through a cation exchange process, i.e., nGP-COOH + Mⁿ⁺ = (nGP-COO)-Mⁿ⁺ + nH⁺ (M = Fe, Ce, Ti), which could adsorb tungstate effectively under the weakly acidic conditions. The optimal initial pH for maximum adsorption of W(VI) was determined at 1~3 for Ti-GP, 1~4 for Fe-GP, and 3 for Ce-GP, respectively; and at pH 2.5, the corresponding maximum adsorption capacity for Fe-GP, Ti-GP, and Ce-GP was evaluated as 91.5 mg/g, 83 mg/g, and 84 mg/g tungsten respectively. Coexisting anions like chloride, sulfate, and carbonate showed little effect on tungsten adsorption, while fluoride and phosphate inhibited the adsorption drastically. The column adsorption showed that the breakthrough point for Ce-GP, Ti-GP, and Fe-GP was 180 min, 200 min, and 270 min respectively. And 0.1 mol/L NaOH effectively eluted the adsorbed tungsten, and concentration of the eluted solution had almost 6, 19.9, and 22 factors of the initial tungstate concentration correspondingly.
Show more [+] Less [-]Investigation of exhaust emissions of an isolated diesel engine blended with ethylhexyl nitrate using experimental and ANN approach Full text
2020
Sevinc, Huseyin | Hazar, Hanbey
Thermal barrier coating (TBC) implementations and oxygenated additives are remarkable issues that may decrease the exhaust emissions of engines. This study examines the effect of chromium oxide (Cr₂O₃) coating and the addition of ethylhexyl nitrate (EHN) on exhaust emissions of a diesel engine. In addition, an artificial neural network (ANN) model was designed which estimates exhaust emissions based on engine speed in order to reduce time, labor, and costs lost in experimental studies, and the performance of the ANN was evaluated. Piston crown and valves of engine were processed with Cr₂O₃. The E3, E6, and E9 blends were produced by blending 3%, 6%, and 9% (vol.) ratios of 2-ethylhexyl nitrate with diesel fuel. Engine speed was used as input parameter and carbon monoxide (CO), nitrogen oxide (NOX), hydrocarbon (HC), and smoke density were used as output parameters. To evaluate the performance of ANN, error rates, and regression (R) values were considered. Experimental results revealed that CO, HC, and smoke density decreased in the CE whereas NOX values increased compared with the UE. The addition of EHN reduced NOX emission and smoke density, whereas it increased CO and HC emissions. The result showed that ANN model can predict the exhaust emissions at a high accuracy rate. The lowest regression results were achieved as 0.98395, 0.99047, 0.99268, and 0.98383 for the CO, NOX, smoke density, and HC, respectively. Moreover, the average R values of NOX, HC, CO, and smoke density were obtained as 0.99767, 0.99131, 0.99396, and 0.99741. The maximum error rates of the estimated outcomes were obtained as 5.25% on average. Graphical abstract
Show more [+] Less [-]Role of public-private partnerships investment in energy and technological innovations in driving climate change: evidence from Brazil Full text
2020
Ahmad, Mahmood | Raza, Muhammad Yousaf
This study aims to examine the impact of public-private partnerships (PPP) investment in energy, technological innovations (TI), economic growth (EG), exports, and foreign direct investment (FDI) on CO₂ emissions in Brazil over the period from 1984 to 2018. In doing so, we employ the Ng-Perron unit root test to examine the stationarity and autoregressive lag distributed (ARDL) model for cointegration between CO₂ emissions and its determinants. The outcomes are as follows: first, in the long run, the PPP investment in energy deteriorates the environmental quality by increasing CO₂ emissions, while TI has a significant negative effect on CO₂ emissions. It is also found that the exports and FDI degrade the environmental quality and the relationship between EG and CO₂ emissions is inverted U-Shaped, presence of the EKC hypothesis. Second, in the short run, PPP investment in the energy sector is negatively influencing, while TI has a positive association with carbon emissions. The empirical findings provide new insights for policymakers to regulate PPP investment in the energy sector for the improvement of environmental quality in Brazil. Graphical abstract
Show more [+] Less [-]The performance of micro-meso-pore HY zeolite for supporting Mo toward oxidation of dibenzothiophene Full text
2020
Dadashi, Mohaddese | Mazloom, Golshan | Akbari, Azam | Banisharif, Farhad
A uniformly distribution of 3 wt.% Mo (with tetrahedral coordination) on a commercial HY zeolite having both micro- and meso-pores, provided a new active catalyst which resulted 100% removal of DBT in this work. Respectively, H₂O₂ and acetonitrile were used as the oxidant and extraction solvent for oxidative desulfurization (ODS) at a mild condition. The structure of three-dimensional meso-pores, despite major micro-pores, was proved to be intriguing for the use of acidic HY zeolite as a support material in this process. The catalyst samples were characterized by different analyses of XRPD, XRF, FTIR, SEM, EDX, TEM, N₂ adsorption desorption, BET, BJH, UV-vis, and NH₃-TPD. High amounts of Mo were not in favor of the catalytic performance because of increasing non-framework polymolybdate formation, which led to decreasing meso-pore volume. Acid sites strength also decreased by increasing Mo content. The Mo active sites at a low loading of 3 wt.% reached the best performance for the complete removal of DBT (t = 90 min, T = 60 °C, catalyst/fuel = 8 g/L, O/S = 2, VSₒₗᵥₑₙₜ/VOᵢₗ = 1/2, DBT = 1000 ppm), mainly due to the presence of isolated Mo species in the framework of HY. The efficiency still reached to 90% after recycling the catalyst three times. The reusability of catalyst revealed the adsorption of the aqueous phase by this hydrophilic catalyst during the process being as a major deactivation factor. This was significantly diminished via a subsequent washing by acetonitrile.
Show more [+] Less [-]Optimizing reaction conditions and experimental studies of selective catalytic reduction of NO by CO over supported SBA-15 catalyst Full text
2020
Souza, Monique S. | Araújo, Rinaldo S. | Oliveira, Alcineia C.
Selective catalytic reduction of NO with CO (CO-SCR) was investigated based on optimizing the operating conditions by response surface methodology (RSM) and by appropriately choosing the supported SBA-15 catalysts. The effects of the CO-SCR reaction parameters such as NO:CO molar ratios and oxygen concentrations on the catalytic performance were determined by RSM to evaluate the NO conversion using a first-order polynomial model. The CuO/SBA-15 and Fe₂O₃/SBA-15 catalysts were synthesized by a hydrothermal method and characterized by X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), N₂ adsorption-desorption (BET), scanning electron microscopy coupled to energy dispersive X-Ray spectroscopy (SEM-EDS), and Fourier transform infrared spectroscopy (FTIR) to investigate the physicochemical properties of the solids. The RSM showed a very good agreement between predicted values and experimental results with the Pareto analysis confirming the accuracy and reliability of the model. The optimized results indicated the maximum NO conversion at 500 °C with using the NO to CO molar ratio of 1:2 (500:1000 ppm) in the absence of oxygen. Under these conditions, CuO/SBA-15 catalyst achieved 99.7% of NO conversion, whereas Fe₂O₃/SBA-15 had 98.1% of the catalytic parameter. Catalytic tests in CO-SCR reaction were performed on both catalysts at optimum operating conditions with CuO/SBA-15 exhibiting better performance compared to that of Fe₂O₃/SBA-15. The results revealed that CuO/SBA-15 was a promising catalyst for CO-SCR of NO due to the well-dispersed CuO phase on SBA-15 surface that allows the solid being more tolerant to the presence of oxygen.
Show more [+] Less [-]Toxicological potential of penconazole on early embryogenesis of white mice Mus musculus in either pre- or post-implantation exposure Full text
2020
El-Shershaby, Abd El-Fattah M. | Lashein, Fakhr El-Din M. | Seleem, Amin A. | Ahmed, Abeer A.
The present investigation was conducted to evaluate the effect of penconazole (PEN) fungicide on early embryogenesis of white mice. In the first experiment, 48 pregnant females were divided into different groups; the first group is control (G1). The second group (G2) was treated daily with PEN (30-, 20-, 10-, 5-mg/kg BW). The third group (G3) was treated with PEN (5-mg/kg BW; day after the other day). The fourth group (G4) was treated with PEN (2.5-mg/kg BW daily) during pre-implantation stage (from the 1st to the 4th day of gestation). The fifth group (G5) was treated with PEN (2.5-mg/kg BW daily) during post-implantation (from the 5th to the 8th day of gestation). The pregnant females were sacrificed at the 14th day of gestation. In the second experiment, 63 pregnant females were classified into control, PEN-treated during pre-implantation period (2.5-mg/kg BW), and PEN-administered during post-implantation period (2.5-mg/kg BW). Each group was sacrificed at stages E6.5, E7.5, E8.5, E9.5, E11.5, E14.5, and E18.5. The high doses of PEN in the first experiment showed failed pregnancy, foetoresorption, and embryo disorganization. High doses of PEN induce alterations in the uterus tissue at the level of histology and immunohistochemistry for the expression of TGFβ2, TNFR2, Caspase 10, and HSP70. The low doses of PEN in the second experiment showed upregulated expression of TGFβ2, TNFR2, Caspase 10, and HSP70 at stages E6.5 and E7.5. In conclusion, PEN was found to alter the suitable uterine environment for proper implantation and development at the levels of histological and immunohistochemical that could create a risk during the full course of embryogenesis.
Show more [+] Less [-]Argyrophilic nucleolar organizer regions in oral mucosa cells of crack and cocaine users: a cross-sectional study Full text
2020
Góes Rabelo, Rosângela | Salgueiro, Arthur Pias | Visioli, Fernanda | da Silva, Viviane Palmeira | das Graças Alonso Oliveira, Maria | Ribeiro, Daniel Araki | Cury, Patricia Ramos | dos Santos, Jean Nunes
The objective of this study was to analyze and compare the presence of argyrophilic nucleolar organizer regions (AgNORs) in exfoliated cells obtained from the buccal mucosa among crack and cocaine users and non-users by the AgNOR staining technique. Seventy-three males ≥ 18 years were categorized into two groups: 38 crack and/or cocaine users and 35 non-user volunteers. They were interviewed and responded a questionnaire regarding general health and drug addiction. Exfoliative cytology specimens were collected from the clinically intact buccal mucosa, and cytological preparations were fixed and stained by AgNOR technique. The mean number of AgNORs (p = 0.02) and the percentage of epithelial cells with more than 3 (p = 0.01) and 4 (p = 0.04) AgNORs/nucleus were significantly higher in the non-user group. In conclusion, the frequency and diversity of substances present in the drugs—cocaine, crack, and alcohol—consumed by the volunteers of this study may have influenced the number of AgNORs and the response to damage and consequent effect on protein synthesis.
Show more [+] Less [-]Biological activity and safety profile of monoterpenes against Plutella xylostella L. (Lepidoptera: Plutellidae) Full text
2020
Cai, Yuehong | Hu, Xian | Wang, Pan | Xie, Yongjian | Lin, Zhufeng | Zhang, Zhilin
Plutella xylostella L. is a cosmopolitan pest of wild and cultivated crucifer vegetables worldwide. It has developed resistance to almost all commercial chemicals, making them one of the most problematic field pests in China. The natural plant extracts and essential oils (EOs) could be a safe alternative for agricultural pests. The development and production of EOs decrease the negative effects of synthetic chemicals. In the present study, the fumigation activity of 8 pure monoterpenes against P. xylostella was evaluated. Results from fumigation tests revealed that 8 tested compounds exhibited various degrees of toxicity against adults of the diamondback moth. Cuminaldehyde was the most toxic compound based on the 12-h LC₅₀ (0.17 mg/L) and 24-h LC₅₀ (0.12 mg/L) values, respectively. Also for larvae and eggs, cuminaldehyde was the most toxic compound. The 12-h LC₅₀ value for cuminaldehyde to 1st, 2nd, and 3rd instar larvae was 0.10 mg/L, 0.12 mg/L, and 0.55 mg/L, respectively. The 24-h LC₅₀ value for the different instar larvae was 0.07 mg/L, 0.09 mg/L, and 0.35 mg/L, respectively. The 24-h LC₅₀ value for eggs (endpoint hatching rate) was 1.95 mg/L for cuminaldehyde, followed by carvacrol and eugenol (2.05 mg/L and 2.31 mg/L, respectively). Cuminaldehyde was very friendly to the larvae and adults of Harmonia axyridis and did not cause any mortality. Our results indicated that cuminaldehyde had potential insecticidal activity against P. xylostella and could be utilized in the novel biological pesticide development.
Show more [+] Less [-]Urinary paraben concentrations and their implications for human exposure in Iranian pregnant women Full text
2020
Hajizadeh, Yaghoub | Kiani Feizabadi, Ghasem | Ebrahimpour, Karim | Shoshtari-Yeganeh, Bahareh | Fadaei, Saeid | Darvishmotevalli, Mohammad | Karimi, Hossein
Parabens are widely used as preservatives in cosmetics, medicines, and foods due to its antimicrobial properties. Concerns have been raised regarding the estrogenic activity and potential endocrine disruption effects of parabens. Studies on monitoring of paraben exposure in the Iranian population are very scarce. This study was carried out to measure urinary concentrations of parabens, to estimate their daily intake, and to identify some of the sociodemographic factors affecting exposure to these compounds. The concentrations of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) were measured in urine samples collected from 95 Iranian pregnant women by gas chromatography mass spectrometry. The highest median concentration was 87.0 μg/L for MP, followed by PP, EP, and BP with median concentrations of 15.6, 9.64, and 8.57 μg/L, respectively. Except BP, the urinary concentrations of other parabens were comparable to those in other countries. Also, the highest daily intake was related to MP (median = 16.5 μg/kg-BW/day), which is less than the acceptable daily intake (ADI). A significant positive correlation was observed between the measured parabens. Significant negative associations were observed between age and BP, BMI and EP as well as parity and PP. On the other hand, income and smoking were significantly positively associated with MP, BP and EP, BP, respectively. The urinary MP and BP concentrations were higher among the subjects with diploma education (P = 0.003 and P = 0.006, respectively), and during the spring, urinary MP concentration was higher than other seasons. The results showed that Iranian pregnant women are more prone to parabens and their urinary paraben concentrations are associated with sociodemographic factors. This result could serve as a basis for evaluating the rate of exposure of the Iranian population to parabens in future studies.
Show more [+] Less [-]Stakeholders’ perspective on strategies to promote contaminated site remediation and brownfield redevelopment in developing countries: empirical evidence from Pakistan Full text
2020
Ahmad, Naveed | Zhu, Yuming | Shao, Jing | Lin, Hongli
Due to the potential of reducing negative outcomes of brownfields on environment and contribution to urban sustainability, brownfield redevelopment (BR) gained considerable recognition in the more recent era. Comprehensive literature shows that many studies proposed strategies to promote BR in developed nations; however, studies focusing on developing economies are scarce. Therefore, this study intends to identify significant strategies to promote BR in developing countries by taking the case of Pakistan. A comprehensive literature review and expert opinion were commenced to identify potential strategies. Data were collected from the main stakeholders involved in BR process through an empirical questionnaire. The findings revealed that “Low-interest loans and subsidies with the collaboration of government and financial institutions,” “Standardized definition, guidelines, and simplified brownfield process,” “Development of technical and infrastructure support,” “Create investors interest,” “Strengthening remediation technologies R&D” were the five most important strategies to promote BR in Pakistan. Theoretically, the novelty of the current study is to highlight the key strategies to promote BR in developing countries. Practically, the study facilitates governments, urban policymakers, environmentalists, and stakeholders to propose and implement appropriate strategies for promoting BR. Future studies can consider modeling the interactions between strategies and their impact on BR adoption.
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