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Bioleaching metals from waste electrical and electronic equipment (WEEE) by Aspergillus niger: a review Texte intégral
2021
Li, Jingying | Xu, Tong | Liu, Jinyuan | Wen, Jiangxian | Gong, Shuli
In the twenty-first century, the increasing demand for electrical and electronic equipment (EEE) has caused its quick update and the shortening of its service life span. As a consequence, a large number of waste electrical and electronic equipment (WEEE) needs to be processed and recycled. As an environmentally friendly method, biometallurgy has received extensive attention in the disposal of WEEE in recent years. Aspergillus niger is an acid-producing fungus with a potential applicability to improve metals’ recycling efficiency. This review article describes the latest statistical status of WEEE and presents the latest progress of various metallurgical methods involved in WEEE recycling for metal recovery. Moreover, based on the summary and comparison towards studies have been reported for bioleaching metals from WEEE by A. niger, the bioleaching mechanisms and the bioleaching methods are explained, as well as the effects of process parameters on the performance of the bioleaching process are also discussed. Some insights and perspectives are provided for A. niger to be applied to industrial processing scale.
Afficher plus [+] Moins [-]Pharmacological implications of ipriflavone against environmental metal–induced neurodegeneration and dementia in rats Texte intégral
2021
Hussien, Hend M. | Ghareeb, Doaa A. | Ahmed, Hany E. A. | Hafez, Hani S. | Saleh, Samar R.
Long-term exposure to environmental neurotoxic metals is implicated in the induction of dementia and cognitive decline. The present study aims to illustrate the therapeutic role of ipriflavone as a synthetic isoflavone against environmental metal–induced cognitive impairment in rats. Dementia was induced by a mixture of aluminum, cadmium, and fluoride for 90 days followed by ipriflavone for a further 30 days. Metal-treated animals exhibited abnormal behaviors in the Morris water maze task. Neuropathological biomarkers including oxidative stress (TBARS, NO, SOD, GPX, GST, and GSH), inflammation (TNF- α, IL-6, and IL-1β), neurotransmission (AChE and MAO), and insulin resistance (insulin, insulin receptor, and insulin-degrading enzyme) were altered, which consequently elevated the level of amyloid-β42 and tau protein in the hippocampus tissues inducing neuronal injury. Ipriflavone significantly (P < 0.05) ameliorated the neurobehavioral abnormalities and the cognitive dysfunction biomarkers via antioxidant/anti-inflammatory mechanism. Moreover, ipriflavone downregulated the mRNA expression level of amyloid precursor protein and tau protein, preventing amyloid plaques and neurofibrillary tangle aggregation at P < 0.05. A molecular docking study revealed that ipriflavone has a potent binding affinity towards AChE more than donepezil and acts as a strong AChE inhibitor. Our data concluded that the therapeutic potential of ipriflavone against dementia could provide a new strategy in AD treatment.
Afficher plus [+] Moins [-]Accumulation of Potentially Toxic Elements in Viola L. (Sect. Melanium Ging.) from the Ultramafic and Non-ultramafic Soils of the Balkan Peninsula Texte intégral
2021
Tomović, Gordana | Đurović, Sanja | Buzurović, Uroš | Niketić, Marjan | Milanović, Đorđije | Mihailović, Nevena | Jakovljević, Ksenija
The aim of the present study was to assess the metal concentrations in five species of the genus Viola L. (section Melanium) from 12 ultramafic outcrops and two non-ultramafic (prolluvium and dolomite) soils from Serbia and Bosnia and Herzegovina. The concentrations of P₂O₅, K₂O, Ca, Mg, Fe, Mn, Zn, Cu, Cr, Co, Cd and Pb in soils and plant samples, as well as their shoot-to-root ratio, biological concentration and accumulation factors were determined. Five investigated Viola species growing on 14 different localities displayed considerable differences in concentration of potentially toxic elements in their roots and its accumulation in their shoots. Viola kopaonikensis and V. beckiana from ultramafic soils could be classified as strong Ni accumulators, since moderately high level of Ni was measured in their shoots (up to 266 mg kg⁻¹ and 337 mg kg⁻¹, respectively), while in V. tricolor high amount of the same element was accumulated in the roots (up to 395 mg kg⁻¹). Population of V. beckiana from dolomitic site in Bosnia and Herzegovina accumulated high concentrations of Pb in the shoots (67.1 mg kg⁻¹), as well as of Cd in both roots and shoots (81.1 mg kg⁻¹ and 60.5 mg kg⁻¹). The results also suggest that V. kopaonikensis populations from the ultramafic soils of Serbia emerge as Cr accumulators, which is quite rare trait within the genus Viola. It seems that species from Melanium section apply quite different strategies against toxic elements. Future studies should strive to explain what adaptive mechanisms are hidden behind it.
Afficher plus [+] Moins [-]A study on the assessment of traffic noise induced annoyance and awareness levels about the potential health effects among residents living around a noise-sensitive area Texte intégral
2021
Gilani, Towseef Ahmed | Mir, Mohammad Shafi
The present cross-sectional study aimed to evaluate the risk factors for traffic noise–induced annoyance and also assess the awareness levels among the exposed population concerning the health impacts caused by traffic noise. Field measurements were made to validate the application of the standard noise models, which were later used to present the acoustical environment and assess the exposure level around a super-speciality hospital surrounded by a residential zone. Results from the noise maps and façade maps revealed that the area was exposed to noise levels exceeding the upper safe limits by more than 10 dB(A). The effect of exposure in the form of annoyance and the awareness level were evaluated using a questionnaire survey in a sample of 565 residents. Attention questions were incorporated in the questionnaire, and the awareness level was evaluated using the mean awareness index score. Respondents living in noisy areas were having a higher risk for annoyance as compared to those living in quiet areas (OR = 4.06; 95% CI = 2.79–5.88). Reporting poor sleep quality, being sensitive to noise, and noise perception at home were the significant risk factors for annoyance. Most of the respondents were classified as having no/little awareness about serious health ailments caused by traffic noise. Lower awareness levels, despite a higher literacy rate and a higher percentage of the young population, imply that there is a need for undertaking mass awareness programmes so that the impacts can be reduced to a minimum, if not eliminated.
Afficher plus [+] Moins [-]Restaurant oil and grease management in Hong Kong Texte intégral
2021
Yau, Yiu-Hung | Rudolph, Victor | Lo, Cat Chui-man | Wu, Kam-Chau
Oil and grease (O&G) in wastewater can be considered as two parts or proportion contained in emulsion which exceeded O&G standard. Most of oil becomes emulsified with water when they pass through grease trap and discharged in the effluents. Thus, it may indicate that either treatment of grease traps or standards for O&G content stipulated in technical memorandum of Water Pollution Control Ordinance (WPCO) do not reflect the actual situation. Existing grease traps should be upgraded to meet the requirements of WPCO. Alternative technologies need to be developed to tackle this unsolved problem. Good management and practices are also important to ensure proper collection and waste recycling rather than just disposing effluent into drains. Collected O&G content can be recycled as valuable products such as biofuel, flotation agent, or other derivatives. This approach not only protects the environment by improving water quality, it also encourages large flow restaurant operators to recycle oil and grease content towards cleaner production.
Afficher plus [+] Moins [-]TiO2/CTS/ATP adsorbent modification and its application in adsorption-ultrafiltration process for dye wastewater purification Texte intégral
2021
Wang, Zhihong | Wu, Zekun | Zhi, Xujun | Tu, Tianfu | Nie, Jinxu | Du, Xing | Luo, Yunlong
Industrial dyeing produces highly polluting wastewater and threatens the environment. Effective treatment of dyeing wastewater is a crucial step to prevent toxic chemicals from entering receiving waters. This study aimed to assess a modified attapulgite (ATP)-based adsorbent for dyeing wastewater purification by introducing chitosan (CTS) and titanium dioxide (TiO₂) into the adsorbent material named TiO₂/CTS/ATP. It was found that after modification, the adsorbent showed a lower hydrophilicity, as demonstrated by an increase in the water contact angle from 9.1° to 42°, which could reduce the water adsorption tendency and potentially facilitate contaminants adherence. The modification also led to a significantly increased specific surface area of 79.111 m²/g from 3.791 m²/g and exhibited more uniform and smaller particle size (reduced from 3.99 to 2.52 μm). When the TiO₂/CTS/ATP adsorbent was applied to the adsorption of Congo red solution, the adsorption efficiency was observed to reach to 97.6% at the dosage of 0.5 g/L. Furthermore, the combination of adsorption and ultrafiltration was able to achieve 99% Congo red removal. Adsorption pretreatment prior to the ultrafiltration also enabled to reduce membrane fouling, increased the reversible membrane fouling, and resulted in a considerably lower transmembrane pressure as compared with the direct ultrafiltration filtration system.
Afficher plus [+] Moins [-]Evaluation of energy use and carbon dioxide emissions from the consumption of fossil fuels and agricultural chemicals for paste tomato cultivation in the Bursa region of Turkey Texte intégral
2021
Demirtas, Muhammet
This study was aimed to determine the fossil fuel consumption, energy use, and carbon dioxide (CO₂) emissions in per unit production area (ha) considering the petroleum products (PP) directly used and the chemical fertilizers and pesticides for the cultivation of paste tomatoes in open-field conditions in Bursa region of Turkey. The primary data of the study consisted of data collected by making face-to-face surveys with the producers of paste tomatoes in the Bursa region. The direct energy inputs and CO₂ emissions related to diesel fuel and lubricant oil consumptions of engines of agricultural tractors for cultivation operations and the indirect energy inputs and CO₂ emissions related to the manufacturing of chemical fertilizers and plant growth regulators used for plant nutrition and pesticides used for plant protection were determined for paste tomato cultivation. A total of 288.6 L diesel fuel and 0.067 L lubrication oil are consumed per hectare when using tools and machinery in paste tomato production. A total of 408 kg of chemical fertilizers and 15.5 kg of pesticides are used per hectare in paste tomato production in the Bursa region of Turkey. A total of 2343.45 MJ/ha and 2700.5 MJ/ha indirect energy is used in the application of chemical fertilizers and pesticides, respectively. A total of 792.43 kg and 0.189 kg CO₂ is released as a result of diesel fuel and lubricant oil consumptions. For the production of one kilogram of paste tomato, 2.68 grams (g) diesel fuel and lubricating oil, 175.02 kilojoules (kJ) of energy is consumed, and 15.88 g CO₂ is released in the Bursa region of Turkey.
Afficher plus [+] Moins [-]Characteristics and chemical speciation of waste copper slag Texte intégral
2021
Li, Zhi | Ma, Guojun | Zhang, Xiang | Li, Jianli
Waste copper slag contains abundant valuable metal element Fe, and residual elements such as Cu, As, Pb, Zn, and Mo. Simply stockpiling or landfilling would waste valuable metal resources and cause contamination due to the leachable harmful elements. In this paper, the HJ/T299-2007 test and TCLP test have been utilized to evaluate the leaching toxicity of waste copper slag, while the sequential extraction procedure was carried out to investigate the different chemical speciation and the bioavailability of the residual metal elements in the waste copper slag. The results show that Pb in the waste copper slag exceeds the regulatory value of TCLP in the leaching tests, which means that the waste copper slag may contaminate the surrounding environment. According to the characteristics of the waste copper slag, the residual metal elements are mainly wrapped by the fayalite or silicate matrix. Cu and Fe are mainly in the form of crystalline iron-manganese oxide by the sequential extraction procedure, while Mo, As, and Zn are mainly in the residual form. Pb mainly exists in the form of carbonate, which is easy to be extracted. The orders of the apparent mobility and potential metal bioavailability of the selected residual metals are Pb>Cu>Zn>As>Mo>Fe.
Afficher plus [+] Moins [-]Testing the environmental Kuznets curve with structural breaks: the role of globalization, energy use, and regulatory quality in South Africa Texte intégral
2021
Güngör, Hasan | Abu-Goodman, Maryam | Olanipekun, Ifedolapo Olabisi | Usman, Ojonugwa
This study uncovers the role of regulatory quality, energy use, and globalization in the conventional environmental Kuznets curve (EKC) for South Africa by incorporating structural breaks in the series based on quarterly frequency data between 1996:Q1 and 2016:Q4. Applying the autoregressive distributed lag (ARDL) model, we confirm a cointegration between the variables. The empirical results suggest the validity of the EKC hypothesis in South Africa. In addition, while energy use exerts positive pressure on ecological footprint, globalization and regulatory quality exert negative pressure on ecological footprint. However, the effect of globalization is weak in the long run while the effect of regulatory quality is weak in short run. The results further reveal that the structural break years are statistically insignificant. The causality result establishes a causal link flowing from all the variables to ecological footprint in the long run. In the short run, economic growth and energy use Granger-cause regulatory quality. Also, while energy use causes ecological footprint, globalization is a predictor of energy use. The policy implication of this study is that increasing the pace of globalization and strengthening regulatory quality are efficient strategies to improve environmental quality and sustain a stable EKC in South Africa.
Afficher plus [+] Moins [-]A bibliometric analysis of publications in Ambio in the last four decades Texte intégral
2021
Ho, Yuh-Shan | Gatto, Andrea
Ambio is a leading journal in environmental science and policy, sustainable development, and human-environment interactions. The paper at hand aims to run a bibliometric analysis to inspect the main publications features of Ambio in Science Citation Index Expanded SCI-EXPANDED. For this scope, a bibliometric survey has been carried out to investigate the journal’s historic characteristics in the Web of Science (WoS) categories of environmental sciences and environmental engineering for Ambio from 1980 to 2019. These are the categories for which the journal has been indexed throughout the indexed time frame. The paper proposes technical and methodological innovations, including improvements in the methods and original characteristics analyzed. Documents published in Ambio were searched out from SCI-EXPANDED. Six publication indicators were applied to evaluate the publication performance of countries, institutes, and authors. Three citation indicators were used to compare publications. As a parameter, the journal impact factor contributor was applied to compare the most frequently cited publications. The journal impact factor contributing publications were also discussed. Results show that Sweden ranked top in six publication indicators and that the top three productive institutes were located in Sweden. A low percentage of productive authors emerged as a journal impact factor contributor. Similarly, a low relationship between the IF contributing publications and the highly cited publications was also found. Less than half of the top 100 highly cited publications in Ambio did not lie within the high impact in most the recent year of 2019. Three members of the advisory board in Ambio were the main productive authors. T.V. Callaghan contributed to most of the publications while papers published by J. Rockstrom as first and corresponding author contributed the most to the journal impact factor. An article authored by Steffen et al. (2007) scored the highest total citations in 2019.
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