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Результаты 3121-3130 из 4,938
Impact of stabilizer on the environmental behavior of PVC films reinforced 1,2,4-triazole moiety Полный текст
2019
Yousif, Emad | Ahmed, Dina S. | Ahmed, Ahmed | Abdallh, Mustafa | Yusop, Rahimi M. | Mohammed, Salam A.
A new Schiff base containing 1,2,4-triazole ring system (L) was synthesized and confirmed by ¹HNMR, FTIR spectroscopy. The chemical modification of PVC with a new Schiff base (L) was synthesized to produce a homogenous blend (PVC-L). A homogenous blend (PVC-L) was added to copper chloride to produce PVC-L-Cu (II). The PVC films had been irradiated with ultraviolet light for a long period and confirmed by FTIR spectroscopy and weight loss; the surface morphology was inspected by scanning electron microscopy.
Показать больше [+] Меньше [-]Use of Salvinia sp on the adsorption of hexavalent chromium Полный текст
2019
Oliveira, Jessika Cabral G. | de Moraes Ferreira, Rachel | Stapelfeldt, Danielle M. A.
The remotion of hexavalent chromium in the form of chromate in aqueous solution was done using the aquatic plant Salvinia sp as biosorbent. The chemical modification of the Salvinia surface was performed by organosolv adapted method. The untreated Salvinia and the modified were characterized by infrared spectroscopy, Boehm titration, scanning electron microscopy, energy dispersive system, point of zero charge, surface area analysis, and porosity. Batch adsorption experiments were performed to observe the effects of pH, contact time, initial concentration, and temperature on the metal removal process. The characterization results show the chemistry modifically changed the modified Salvinia structure compared with untreated Salvinia. The adsorption test results showed the maximum adsorption capacity of 26.03 mg g⁻¹. The kinetic equilibrium was reached in about 3 h, and the better temperature and pH were 298 K and 7, respectively. The adsorption and kinetic models were Freundlich and pseud-second order, respectively. This study showed the Salvinia sp after the chemical treatment can be used with biosorbent for hexavalent chromate in the form of chromate, being a natural material with low cost and plentiful in the environment.
Показать больше [+] Меньше [-]Uncovering the driving forces of carbon dioxide emissions in Chinese manufacturing industry: An intersectoral analysis Полный текст
2019
Shi, Yingying | Han, Botang | Zafar, Muhammad Wasif | Wei, Zixiang
As the pillar of national economy, manufacturing industry is the largest primary energy consumer and emitter of carbon dioxide (CO₂) in China. Therefore, capturing the determinants of CO₂ emissions in manufacturing industry is extremely important for national efforts to mitigate carbon emissions. This paper explores the major driving forces behind CO₂ emission changes in China’s manufacturing industry during 2000–2015 from perspectives of the whole sector and 28 subsectors, by applying the temporal logarithmic mean Divisia index (LMDI) method. Moreover, an intersectoral LMDI model is built to uncover the intersectoral discrepancies of CO₂ emissions among 28 subsectors. The temporal analysis indicates that industrial activity and energy intensity are crucial factors respectively contributing to the increase and mitigation of CO₂ emissions. The intersectoral analysis reveals that energy intensity is the dominant factor responsible for the intersectoral discrepancies of CO₂ emissions among 28 subsectors. The great mitigation towards CO₂ emissions can be achieved if energy efficiency is largely improved in carbon-intensive subsectors. Priority should be given by governments to the industrial technology advancement, such as subsidies for energy-saving technological transformation and promotion of international advanced techniques and equipment, which can greatly improve production efficiency and mitigate emissions in manufacturing industry.
Показать больше [+] Меньше [-]Orchard management under the effects of climate change: implications for apple, plum, and almond growing Полный текст
2019
Gitea, Manuel Alexandru | Gitea, Daniela | Tit, Delia Mirela | Purza, Lavinia | Samuel, Alina Dora | Bungău, Simona | Badea, Gabriela Elena | Aleya, Lotfi
The authors analyzed certain species and varieties of fruit tree in which applied crop technology is used and also undergoes the effects of climate change. The aim is to extend productive crop varieties, resistant to disease and pests, in order to obtain superior yields. The research was conducted in orchards located in northwestern Romania (on 8.59 ha), intensively cultivated with apple, plum, and almond species. The blooming period of the species and fruit production was studied in 2009, the first year of the farm’s commercial production, and then compared to figures from 2016 to see the changes that occurred. Climatic conditions were studied throughout the period of existence of the farm (2002–2016). To determine the influence of the climatic factor on the blooming and production periods, respectively, every year is considered having pre-blooming, blooming, and ripening periods. It was found that climate change influences the annual biological cycle of the trees: the vegetative rest period of the trees shortens, the tree vegetation begins earlier in the spring, and the blooming period is advanced by as much as 10 days compared to normal cultivated varieties. All these factors have direct repercussions on the quantity of production.
Показать больше [+] Меньше [-]Ecotoxicological biomarkers as investigating tools to evaluate the impact of acrylamide on Theba pisana snails Полный текст
2019
Radwan, Mohamed A. | El-Gendy, Kawther S. | Gad, Amira F. | Khamis, Awatef E. | Eshra, El-Sayed H.
Acrylamide (ACR) is a widespread industrial chemical with recognized adverse effects not only to humans but to other organisms in the environment as well. In the present study, the ecotoxicological effects of dietary exposure to sublethal concentration (1/20 LC₅₀) of ACR on the land snail, Theba pisana after 2 weeks of exposure and 1-week recovery with respect to oxidative stress parameters; lipid peroxidation (LPO), reduced glutathione (GSH), catalase (CAT), and glutathione-S-transferase (GST), cytogenetic parameter; deoxyribonucleic acid (DNA) content, as well as immunological parameters; cell death, phagocytosis, lysosomal membrane stability (LMS), lectins, superoxide anion (O₂⁻) generation, phenoloxidase (PO), peroxidase (POD), and hemocyanin (Hc) were examined. The results showed that ACR significantly increased LPO level and the activity of CAT and GST, cell death, and Hc level, whereas a significant decline in DNA and GSH contents, phagocytic activity, LMS, lectins, O₂⁻ generation, POD, and PO activities compared to the controls after 2-week exposure was observed. After 1-week recovery, most of the tested parameters in exposed snails were permanent and not reversible to the control levels. This study suggests that the tested multiple parameters of T. pisana species may be used as biomarkers of ACR exposure. Besides, T. pisana snails could be used as a good sentinel organism for ACR exposure in pollution monitoring studies.
Показать больше [+] Меньше [-]Phthalates in residential and agricultural soils from an electronic waste-polluted region in South China: distribution, compositional profile and sources Полный текст
2019
Zhang, Shao-hui | Guo, Ai-jing | Fan, Tong-tong | Zhang, Rong | Niu, Yu-jie
Electronic waste (e-waste) recycling has proven to be a significant source of phthalate (PAE) contamination in the environment. A detailed investigation was conducted to understand the concentration, distribution, profile and possible source of PAEs in residential and agricultural soils from Guiyu, Shantou, China, the largest e-waste processing and recycling areas in the world. Sixteen PAEs were analysed in 46 surface soil samples from three different sampling areas in terms of individual and total concentrations, together with pH and soil organic matter. High concentrations of the total PAEs were found in residential area A (more than 20,000 ng g⁻¹), revealing a clear urban pulse, whereas in residential area B and agricultural areas, concentrations were lower than 10,000 ng g⁻¹. The dominant PAEs were bis (2-nbutoxyethyl) phthalate, bis (4-methyl-2-pentyl) phthalate and dicyclohexyl phthalate. These PAEs were high-molecular weight PAEs (alkyl chains ≥ 6 carbons) and mainly derived from polyvinyl chloride commonly used in electrical and electronic equipment, indicating a distinctive composition in relation to the e-waste area. Three individual and the total PAEs exhibited significant positive correlations with pH. Principal component analysis indicated that PAEs were mainly distributed in three groups according to the alkyl chain length and potential source. This study showed that the informal e-waste recycling has already introduced PAEs into surrounding areas as a pollutant which should draw more attention and regulatory control.
Показать больше [+] Меньше [-]Effects of long-term 4-nonylphenol dietary exposure on reproductive ability of Japanese quails (Coturnix japonica) Полный текст
2019
As an endocrine disruptor, 4-nonylphenol (4-NP) is widespread in the environment. Here, we investigated the effect of long-term 4-NP dietary exposure on Japanese quails (Coturnix japonica). A total of 72 quails were evenly divided into 24 cages (12 cages for the reproductive toxicity study and 12 cages for the histopathology study, with one male quail and two female quails in each cage) and fed with various doses of 4-NP in diet. The body weight in quails administered with 4-NP was significantly decreased (P < 0.05) in a time- and dose-dependent manner. The egg fertilization rate significantly decreased (P < 0.05) in all treated groups, which was 91.4%, 86.5%, 85.4%, and 86.2% in the control group, 10 mg·kg⁻¹, 20 mg·kg⁻¹, and 50 mg·kg⁻¹ treatment groups, respectively. Moreover, the hatching rate was also significantly decreased (P < 0.05) in the 50 mg·kg⁻¹ treatment group compared with the control group. Furthermore, the 14-day survival rate of young quails was significantly decreased (P < 0.05) in all treated groups, which was 98.0%, 91.1%, 89.8%, and 86.8% in the control group, 10 mg·kg⁻¹, 20 mg·kg⁻¹, and 50 mg·kg⁻¹ treatment groups, respectively. Damaged spermatogenesis in male quails was found in all treated groups. In conclusion, oral administration of 4-NP impaired the gonads of male quails, leading to reproduction performance damage of Japanese quails.
Показать больше [+] Меньше [-]Guiding the development of sustainable nano-enabled products for the conservation of works of art: proposal for a framework implementing the Safe by Design concept Полный текст
2019
Nanotechnology provides innovative and promising solutions for the conservation of cultural heritage, but the development and application of new nano-enabled products pose concerns regarding their human health and environmental risks. To address these issues, we propose a sustainability framework implementing the Safe by Design concept to support product developers in the early steps of product development, with the aim to provide safer nano-formulations for conservation, while retaining their functionality. In addition, this framework can support the assessment of sustainability of new products and their comparison to their conventional chemical counterparts if any. The goal is to promote the selection and use of safer and more sustainable nano-based products in different conservation contexts. The application of the proposed framework is illustrated through a hypothetical case which provides a realistic example of the methodological steps to be followed, tailored and iterated along the decision-making process.
Показать больше [+] Меньше [-]A comparative study of using barberry stem powder and ash as adsorbents for adsorption of humic acid Полный текст
2019
In the present research, investigation of the practical utility of barberry stem powder (BSP) and barberry stem ash (BSA) for humic acid (HA) removal from an aqueous medium by adsorption was carried out. The adsorption process was tested by varying of pH (3–11), reaction time (5–20 min), initial HA concentration (5–40 mg/L), adsorbent dosage (1–4 g/L), and temperature (15–35 °C). The isothermal results revealed that the adsorption process is favorable for both used adsorbents and it is highly described using the Freundlich and Langmuir models (R² > 0.960). Also, the maximum uptakes of BSP and BSA for HA were 20.220 and 16.950 mg/g at the abovementioned optimized conditions (pH = 7, reaction time = 10 min, temperature = 15 °C, initial HA concentration = 40 mg/L, and adsorbent amount = 1.0 g/L), respectively. The results achieved from the fitting of the experimental data with Dubinin-Radushkevich isotherm model showed that the HA molecules are adsorbed onto the BSP and BSA by physiosorption process. From the thermodynamic study, it appeared that the biosorption process of the HA onto two studied adsorbents was of exothermic nature. The kinetics of the adsorption process of HA has been found to be pseudo-second-order model (R² = 0.930–0.999). Thus, the results obtained from this paper elucidated that the BSP exhibited higher adsorption capacity in comparison to BSA, for HA removal up to permissible concentrations.
Показать больше [+] Меньше [-]Efficacy of two actinomycete extracts in the amelioration of carbon tetrachloride–induced oxidative stress and nephrotoxicity in experimental rats Полный текст
2019
Actinomycetes are a group of the Gram-positive bacteria famous for their antimicrobial, anticancer, anti-parasitic, and anti-inflammatory activities. This study aimed to investigate the efficacy of two bacterial extracts derived from two soil actinomycete strains (S19 and G30) against carbon tetrachloride (CCl₄)–induced nephrotoxicity in experimental rats. Sixty-four male rats were assigned to four groups of 16 rats in each group. The 1st group was kept as a normal (control) group and given corn oil combined with the used production medium, while the 2nd group received only CCl₄ (CCl₄ group). On the other hand, the 3rd group (CCl₄+S19) was administered CCl₄ and the extract of the actinomycete strain S19 and the 4th group (CCl₄+G30) received CCl₄ and the extract of the actinomycete strain G30, both treatments for 8 weeks. The results revealed that the two actinomycete extracts S19 and G30 could significantly (p < 0.01) lower the elevated levels of serum creatinine, urea, and uric acid caused by the CCl₄ administration. Additionally, the two actinomycete extracts improved the decreased serum total protein. Interestingly, treatment of the CCl₄-intoxicated rats with S19 and G30 extracts remarkably reversed the lowered renal glutathione (GSH), glutathione peroxidase (GSH-Px), peroxidase (Px) and superoxide dismutase (SOD) activities, and the elevated lipid peroxidation (LPO) levels. The histopathological examination of the treated kidney revealed that the two actinomycete extracts improved rats against CCl₄-induced kidney lesions. The present results suggested that the protective effect of the two actinomycete extracts may rely on its effect on reducing the oxidative stress and improving the antioxidant defense system.
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