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Результаты 4381-4390 из 4,937
Sustainable solid waste management system using multi-objective decision-making model: a method for maximizing social acceptance in Hoi An city, Vietnam Полный текст
2019
Hoang, Giang Minh | Fujiwara, Takeshi | Pham Phu, Toan Song | Nguyen, Luong Duc
The main aim of this study was to develop a decision support system for sustainable municipal solid waste management (MSWM) in Hoi An city (HAC), Vietnam. A face-to-face interview was conducted with local experts including authorities, citizens, waste collection contractors and recyclers to identify main objectives of waste management system and appropriate treatment methods. A multi-objective optimization model was proposed using non-linear programming approach. An interactive method known as reference point method (RPM) was applied for solving the problem with three objectives including cost minimization, landfill minimization and emission minimization. As a result, the efficient waste-flow-allocation and the optimal capacity of disposal facilities were determined by intense discussion and agreement among decision-makers. Waste incineration, anaerobic digestion, sanitary landfill and current recycling activities should be applied with a cost of about 2300 US$ daily. Also, the daily emission of various pollutants was about 35 metric tons, and the greenhouse gas (GHG) is 313 tons CO₂₋ₑq.
Показать больше [+] Меньше [-]Preparation and characterization of PVDF/CaCO3 composite membranes etched by hydrochloric acid Полный текст
2019
Bei, Pengzhi | Liu, Hongjing | Yao, Hui | Hu, Aijun | Sun, Yong | Guo, Liying
This study aimed to improve the pore size, porosity, and hydrophobicity of polyvinylidene fluoride (PVDF) membranes for desalination by vacuum membrane distillation (VMD). New membranes were prepared via etching PVDF/calcium carbonate (CaCO₃) composite membranes using hydrochloric acid (HCl), depending on the chemical reaction of CaCO₃ and HCl. Etched membranes were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), contact angle (CA), atomic force microscope (AFM), and scanning electron microscopy (SEM). The results showed that CaCO₃ of composite membranes was completely reacted by 1.5 mol/L HCl after composite membranes had been etched 90 min. The crystallinity of etched membranes was the same as that of PVDF/CaCO₃ composite membranes, and no new functional groups appeared in etched membranes, which indicated that etched membranes had good chemical stability. The surface roughness increased and led to the increase of contact angle, which means the hydrophobicity of etched membranes was enhanced. As a result, the increment of permeation flux had been improved in a VMD process. It was found that the maximum flux of etched membrane was enhanced and up to 1.65 times of composite membrane when the concentration of sodium chloride (NaCl) solution was 5.0 wt%, and the maximum flux reached up to 30.9 kg m⁻² h⁻¹.
Показать больше [+] Меньше [-]Nicotine increased VEGF and MMP2 levels in the rat eye and kidney Полный текст
2019
Ateş, Mehmet | Hosgorler, Ferda | Yuksel, Oguz | Unsal, Sultan Kaya | Guvendi, Guven | Karakilic, Asli | Koc, Basar | Kandis, Sevim | Kanit, Lutfiye | Uysal, Nazan
Chronic cigarette smoking affects many tissues negatively. Nicotine in tobacco has negative effects on tissues, kidneys, and eyes especially, where microcirculation is vitally important for the survival and functioning. It is known that appropriate vascular endothelial growth factor (VEGF) and (matrix metalloproteinase 2) MMP2 levels are required for suitable vascularity and enough microcirculation. The aim of this study was to investigate the effect of nicotine on VEGF and MMP2 levels in kidney and eyes, where microcirculation is very important for their function. The nicotine was given into drinking water, to male and female rats for 6 weeks. During the first 2 weeks, the nicotine concentration was 10 mg/L, then was given at a fixed dose of 20 mg/L until the end of the experiment. The VEGF and MMP2 levels were increased in kidney tissue of both genders as a result of given nicotine. MMP2 levels were also increased in the eye tissue for both genders similarly. However, VEGF levels increased in the eye tissue with nicotine in males, whereas it did not change in females. The use of nicotine made VEGF and MMP2 levels increase in kidney tissue in both genders of rats. This increase in VEGF was observed only in male eye tissue, not in females. According to our findings, it can be suggested that nicotine has negative effects on microvascular circulation by increasing VEGF and MMP2 levels. In addition, it should be pointed out that estrogen might have protective effects on female eye tissue. Further studies are necessary to understand the complex relationship between the role of nicotine and estrogen on eye and kidney tissues.
Показать больше [+] Меньше [-]The motivations of Chinese firms in response to the Carbon Disclosure Project Полный текст
2019
Li, Huiyun | Fu, Shaoyan | Chen, Zheng | Shi, Jing | Yang, Zheyuan | Li, Zhaohai
Through an analysis of data gathered from Chinese firms surveyed by the Carbon Disclosure Project (CDP), this paper studies the motivations of Chinese firms to respond to the CDP. The results indicate that (1) Chinese firms are more inclined to respond to the CDP survey for the sense-making motivation; (2) Chinese firms are less inclined to respond to the CDP survey due to the existence of proprietary costs for information disclosure; (3) self-interested political motivation is a negative motivation for Chinese firms to respond to the CDP survey; state-owned enterprises (SOEs) are less inclined to respond to the CDP survey than are non-SOEs; and (4) Chinese firms did not consider a financing motivation when deciding whether to respond to the CDP survey. However, the results of our further research show that if firms actively respond to the CDP survey, their financing constraints can be significantly reduced. This paper studies the four motivations for Chinese firms to respond to the CDP survey, contributing to the research of carbon emission disclosure. This paper highlights the importance of corporate carbon awareness for carbon emission disclosure, builds an understanding of the internal driving forces of response to the CDP survey among Chinese firms, and thus promotes the increase of Chinese corporate disclosure of carbon emission.
Показать больше [+] Меньше [-]The cytotoxic, inflammatory and oxidative potential of coconut oil-substituted diesel emissions on bronchial epithelial cells at an air-liquid interface Полный текст
2019
Vaughan, Annalicia | Stevanovic, Svetlana | Banks, Andrew P. W. | Zare, Ali | Rahman, Md Mostafizur | Bowman, Rayleen V. | Fong, Kwun M. | Ristovski, Zoran D. | Yang, Ian A.
Diesel emissions contain high levels of particulate matter (PM) which can have a severe effect on the airways. Diesel PM can be effectively reduced with the substitution of diesel fuel with a biofuel such as vegetable oil. Unfortunately, very little is known about the cellular effects of these alternative diesel emissions on the airways. The aim of this study was to test whether coconut oil substitution in diesel fuel reduces the adverse effect of diesel emission exposure on human bronchial epithelial cells. Human bronchial epithelial cells were cultured at air-liquid interface for 7 days and exposed to diesel engine emissions from conventional diesel fuel or diesel fuel blended with raw coconut oil at low (10%), moderate (15%) and high (20%) proportions. Cell viability, inflammation, antioxidant production and xenobiotic metabolism were measured. Compared to conventional diesel, low fractional coconut oil substitution (10% and 15%) reduced inflammation and increased antioxidant expression, whereas higher fractional coconut oil (20%) reduced cell viability and increased inflammation. Therefore, cellular responses after exposure to alternative diesel emission are dependent on fuel composition.
Показать больше [+] Меньше [-]Development of novel sericin and alginate-based biosorbents for precious metal removal from wastewater Полный текст
2019
Santos, Nilza Tatiane das Graças | da Silva, Meuris Gurgel Carlos | Vieira, Melissa Gurgel Adeodato
In this study, two novel low water-soluble sericin and alginate-based biosorbents were successfully developed for precious metal removal from wastewater: sericin and alginate particles chemically crosslinked by proantocyanidins (SAPAs) and sericin, alginate and polyvinyl alcohol particles (SAPVA). The proportions of proantocynidins (PAs) or polyvinyl alcohol (PVA) added to sericin (2.5% w/v) and alginate (2.0% w/v) blend were 0.5, 1.5, 2.5 and 3.5% w/v. Among these concentrations, particles produced with 0.5% w/v of PVA or 2.5% w/v of PAs presented the lowest water solubility percentages (3.74 ± 0.05 and 3.56 ± 0.21%, respectively) and the following metallic affinity order: AuCl₄⁻ > PdCl₄²⁻ > PtCl₆²⁻ > Ag⁺. Then, gold biosorption kinetics by SAPAs was evaluated at three gold initial concentrations (72.88, 187.12, and 273.79 mg/L), and its performance was compared to activated carbon adsorbent uptake. The data modeling revealed that the process follows pseudo-first-order kinetics and is mainly controlled by external diffusion. SAPAs before and after gold biosorption (SAPAs-gold) were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, optical microscopy, helium pycnometry, mercury porosimetry, N₂ physisorption, and Fourier-transform infrared spectroscopy.
Показать больше [+] Меньше [-]Transformation of atrazine by photolysis and radiolysis: kinetic parameters, intermediates and economic consideration Полный текст
2019
Rózsa, Georgina | Fazekas, Ákos | Náfrádi, Máté | Alapi, Tünde | Schrantz, Krisztina | Takács, Erzsébet | Wojnárovits, László | Fath, Andreas | Oppenländer, Thomas
Four techniques, UV₂₅₄ ₙₘ photolysis, vacuum ultraviolet (VUV₁₇₂ ₙₘ) photolysis, combined UV₂₅₄ ₙₘ/VUV₁₈₅ ₙₘ photolysis and gamma (γ) radiolysis were used to induce the transformation of atrazine in aqueous solution. The effects of dissolved oxygen (atrazine concentration 1 × 10⁻⁴ mol L⁻¹ and 4.6 × 10⁻⁷ mol L⁻¹) and matrix (high purity water/purified wastewater, atrazine concentration 4.6 × 10⁻⁷ mol L⁻¹) and the electric energy requirements were investigated. The calculation of the energy input in cases of the photolyses was based on the lamp’s power. In radiolysis, the absorbed dose (J kg⁻¹) was the basis. In UV photolysis, atrazine transforms to atrazine-2-hydroxy; this product practically does not degrade during UV photolysis; due to this reason, the mineralisation is very slow. This and some other products of atrazine decomposition degrade only in radical reactions. Dissolved oxygen usually slightly enhances the degradation rate. At 10⁻⁷ mol L⁻¹ concentration level, the matrix, high purity water/purified wastewater, has not much influence on the degradation rates in UV photolysis and radiolysis. In the VUV and UV/VUV systems, considerable matrix effects were observed. Comparing the electric energy requirements of the four degradation processes, radiolysis was found to be the economically most feasible method, requiring 1–2 orders of magnitude less electric energy than UV/VUV, VUV and UV photolysis.
Показать больше [+] Меньше [-]Growth and biochemical changes in quail bush (Atriplex lentiformis (Torr.) S.Wats) under Cd stress Полный текст
2019
Eissa, Mamdouh A. | Abeed, Amany H.A.
Halophytes have several advantages to be more effective in metal phytoextraction. Little is known about the Cd-phytoextraction potential of Atriplex lentiformis under different levels of Cd. Seven levels of Cd (0, 40, 80, 120, 160, 200, and 240 mg per kg of soil) were added to A. lentiformis plants grown on pots filled with 5 kg of sandy loam soil. A. lentiformis plants achieve different defense mechanisms to meet the high concentration of Cd in the soil and plant. These mechanisms include reducing the number and area of leaves, minimizing chlorophyll synthesis, and enhancing synthesizing of oxalic acid, phenols, and proline. The critical point of Cd was 9.35 and 183 mg kg⁻¹ for available soil Cd and leaves concentrations, respectively. The maximum level of Cd displayed a 66% decrease in the chlorophyll content of the leaves. On the other hand, the oxalic acid, phenols, and proline in the leaves were increased significantly by 129, 100, and 200% when Cd increased from 0 to 240 mg. The tested plant removed 3.6% of the total soil Cd under the low Cd concentration (40 mg) but under the high level of Cd (240 mg), it only removed a negligible amount of soil Cd (0.74%). The current study confirmed that A. lentiformis plants lost the ability to cleanup Cd from contaminated soil under the high levels of contamination due to the high reduction in the production of dry matter.
Показать больше [+] Меньше [-]Adsorption of gallic acid on nanoclay modified with poly(diallyldimethylammonium chloride) Полный текст
2019
Celestino, Gustavo G. | Henriques, Ruan R. | Shiguihara, Ana L. | Constantino, Vera R. L. | de Siqueira Melo, Rodrigo | Amim Júnior, Jorge
In this work, particles of nanoclay modified with poly(diallyldimethylammonium), PDDA, namely PDDA/PGV, were obtained and characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), surface area measurement (BET surface area), measurement of zero charge point (pHPCZ), and scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS). The PDDA/PGV particles were applied as adsorbent for the removal of gallic acid (GA) from aqueous solution. The effect of various parameters, such as solution pH, contact time, adsorbent mass, and temperature, was studied. The maximum adsorption capacity of PDDA/PGV (238.45 mg g⁻¹) was observed at pH 4 and 15 °C. The study of adsorption kinetics and isotherms revealed that the adsorption process was better fitted by pseudo-first order and Freundlich model, respectively. The obtained thermodynamic parameters indicate that the adsorption of GA is spontaneous and enthalpy-driven.
Показать больше [+] Меньше [-]The nephroprotective effects of allicin and ascorbic acid against cisplatin-induced toxicity in rats Полный текст
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.
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