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Analysis of Fluorescence and Biodegradability of Wastewater
2019
Zhu, Pengyu | Zhu, Kaijin | Puzey, Rob | Ren, Xiaoli
Three-dimensional fluorescence spectrometer was adopted for the content analysis of different types of organics in coking wastewater before biochemical treatment and through biochemical treatment, and the model of parallel factors was employed to analyze fluorescence components and contents. It was found that tryptophan-like components were the most easily degraded by biology, while humic-like components were the least easily degraded. Meanwhile, it had been seen that the change trends over time of total fluorescence densities of proteinoid fluorescence, and degradable organic fluorescence were highly consistent with that of parameter values of COD, NH₃-N in this wastewater after analyzing the trends of the two indexes. It was proved that the three-dimensional fluorescence spectrum method was appropriate for the accurate degradation analysis of wastewater components.
显示更多 [+] 显示较少 [-]Optimization of Benzodiazepine Drugs Removal from Water by Heterogeneous Photocatalysis Using TiO2/Activated Carbon Composite
2019
Cunha, Deivisson L. | Kuznetsov, Alexei | Araujo, Joyce R. | Neves, Rodrigo S. | Archanjo, Braulio S. | Canela, Maria Cristina | Marques, M. (Marcia)
Widely consumed benzodiazepine drugs are emerging contaminants, some of them being endocrine disruptors. Although many of these drugs remain in wastewater even after conventional treatment, innovative treatability studies are still sparse. The aim of this study was to investigate the efficiency of heterogeneous photocatalysis using synthesized composites based on TiO₂ and activated carbon (TiO₂/AC) as catalysts under sunlight-simulated irradiation. Different ratios and calcination temperatures were tested for the synthesis, and the composite with the best photocatalytic efficiency (based on methylene blue dye removal from water solution) was the one formed by 10% AC calcined at 400 °C (TiO₂/AC10%). This composite was applied in heterogeneous photocatalysis to remove bromazepam, clonazepam, and diazepam at environmentally relevant concentrations (100 μg/L). Such treatment approach has not been reported in the literature to date. Independent variables such as catalyst concentration, pH, and sunlight-simulated irradiation were studied using design of experiments (DoE) to find conditions that provide maximum removal efficiency. TiO₂/AC10% powder was characterized by SEM, XRD, BET, and diffuse reflectance. Under feasible optimized conditions, the efficiency of TiO₂/AC10% to remove benzodiazepine drugs from water was > 97.5%, which is much higher than the removal obtained with commercial catalyst and all controls.
显示更多 [+] 显示较少 [-]Nobel Materials (ZnO Nanoparticles and ZnO Nanoparticles Supported on a Zeolite) for the Removal of Tartrazine from Aqueous Solutions
2019
Alcantara-Cobos, A. | Solache-Rios, M. | Gutiérrez-Segura, E.
Two materials (ZnO nanoparticles (nanZnO) and a composite (Ze-nanZnO)) were prepared; the composite was prepared by chemical precipitation on a natural zeolite. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy (UV-Vis), and Branauer-Emmett-Teller (BET) surface area. These materials were evaluated for the removal of tartrazine; this dye was used because it is considered a dangerous contaminant. All experiments were done in batch process. The effect of different parameters such as the contact time, the initial dye concentration, and pH, in addition to the thermodynamic parameters, were studied in order to determine the best experimental conditions. The nanZnO shows a higher adsorption capacity than the Ze-nanZnO composite; however, the separation of the phases was difficult when nanoparticles were used. According to the kinetic data, the mechanism for the nanZnO is physisorption and for the Ze-nanZnO composite is chemisorption. The results show that this is a useful technique for the removal of this dye.
显示更多 [+] 显示较少 [-]Removal of Cu and Zn from Aqueous Solutions by Selected Tree Leaves with Phytoremediation Potential
2019
Massadeh, Adnan M. | Massadeh, Saif Addeen A.
In this study, some different selected plant leaves grown in Jordan such as Citrus limon (Rutaceae), Ceratonia siliqua L., Olea europaea (Oleaceae), Washingtonia filifera, and Myoporum (Myoporaceae) were examined for removal of copper (Cu) and zinc (Zn) ions from aqueous solutions. Cu and Zn were analyzed by atomic absorption spectrometry. A pH S-2 acidometer was used for determining the acidity of leaves solution system. Our findings showed the plants leaves were relatively efficient for removal of Cu and Zn compared to activated carbon. Removal of a 5 mg/L aqueous metal solution of Cu and Zn was treated with 2.5 g oven-dried plant in a 50 mL deionized water. The removal of Cu and Zn was expressed in terms of a time function ranged between 0 and 192 hours of contact time. The uptake of Cu and Zn by plant leaves was arranged in the following order:(i)Cu: Activated carbon > Washingtonia filifera > Ceratonia siliqua L. > Olea europaea (Oleaceae) > Myoporum (Myoporaceae) > Citrus limon (Rutaceae)(ii)Zn: Activated carbon > Olea europaea (Oleaceae) > Citrus limon (Rutaceae) > Ceratonia siliqua L. > Washingtonia filifera > Myoporum (Myoporaceae)
显示更多 [+] 显示较少 [-]The Possibilities of Using Broadleaf Cattail Seeds (Typha latifolia L.) as Super Absorbents for Removing Aromatic Hydrocarbons (BTEX) from an Aqueous Solution
2019
Ciesielczuk, Tomasz | Rosik-Dulewska, Czesława | Poluszyńska, Joanna
Sorption of oil-related products (including mainly the propellants) is the very basic process that counteracts spreading these types of pollution into environment. Plenty of synthetic substances (including the monoaromatic hydrocarbons) are both from the surface and underground waters. The aim of this study was to present the research’s results on the possibilities of using the broadleaf cattail (Typha latifolia L.) seeds as a sorbent of monoaromatic hydrocarbons from an aqueous solution. In order to increase sorptive capacity, the seeds biomass was submitted for the process of mercerizing in diversified time and temperature in water and the NaOH solution. The removal of benzene, toluene, ethylbenzene, o-xylene, m-xylene and cumene was carried out by means of the “batch method”. All the conducted experiments have shown a high sorption level of the analysed pollutions from an aqueous solution. The best sorptive qualities appeared in the seeds drenched in 80 °C water for 4 h (W) 97 g/kg, what was 9.06% more absorbed hydrocarbons in comparison to the control sample (C) and 26.8% more than the smallest seeds drenched in NaOH for 240 min. in the temperature of 80 °C (N). The process of the seeds mercerizing that was conducted with the use of hot water appeared to be most effective, but seeds without mercerisation (C) is actually the material which absorbs the least amounts of energy for preparation and had quite good sorption capacity too.
显示更多 [+] 显示较少 [-]Does agricultural value added induce environmental degradation? Empirical evidence from an agrarian country
2019
Agboola, Mary Oluwatoyin | Bekun, Festus Victor
This study empirically investigates the agriculture-induced environmental Kuznets curve (EKC) hypothesis in an agrarian framework. Annual time series data from 1981–2014 was employed using augmented Dickey–Fuller and the Phillips–Perron (PP) unit root test complemented by the Zivot and Andrews unit root that accounts for a single structural break to ascertain stationarity properties of variables under consideration. For the cointegration analysis, an autoregressive distributive lag methodology and the recent novel Bayer and Hanck combined cointegration technique are employed. For the direction of causality, the Granger causality test is used as estimation technique. Empirical findings lend support for the long-run equilibrium relationship among the variables under consideration. This study also validates the inverted U-shaped pattern of EKC for the case of Nigeria, affirming that Nigeria remains at the scale-effect stage of its growth trajectory. Further empirical results show that foreign direct investment attraction helps mitigate carbon emissions in Nigeria. Based on these results, several policy prescriptions on the Nigeria energy mix and agricultural operations in response to quality of the environment were suggested for policymakers, stakeholders, and environmental economists that formulate and design environmental regulations and strategies to realise the goal 7 of sustainable development (SDG).
显示更多 [+] 显示较少 [-]Ultrathin Support-Free Membrane with High Water Flux for Forward Osmosis Desalination
2019
Zheng, Meiyu | Zhao, Xiaoyu | Xu, Shu | Lu, Dongwei
In this work, an ultrathin polyamide (PA) membrane was fabricated via in situ removing polysulfone (PSF) substrate from the PSF-PA forward osmosis membrane for the first time. The physicochemical properties of the PA membranes were confirmed by means of surface morphology, chemistry analysis, and surface charge characterization. The performance of PA, PSF-PA, and physically combined PSF+PA membrane was compared in terms of water flux, reverse salt flux, and selectivity. The flux performance of these three membranes followed the order of PA>PSF-PA>PSF+PA membranes, and the possible mechanism for their performance was proposed. Compared with home-made PSF-PA and PSF+PA membranes, the ultrathin PA membrane had high water flux (i.e., 80.54 LMH) due to its low membrane resistance and minimized internal concentration polarization under same operation conditions (i.e., DI water feed solution, 1.0 M NaCl draw solution, and AL-FS orientation). This study would provide insights on the preparation and application of ultrathin PA membranes with high permeability in the context of global water/energy-related crisis.
显示更多 [+] 显示较少 [-]Ecophysiological Responses of a Willow Cultivar (Salix miyabeana ‘SX67’) Irrigated with Treated Wood Leachate
2019
Frédette, Chloé | Comeau, Yves | Brisson, Jacques
As wood preservatives leach from exposed treated wood, they contaminate soil and water, creating an environmental problem that needs to be addressed. Treating this contamination is particularly challenging since it includes mixed compounds, such as heavy metals and trace elements, as well as xenobiotic organic pollutants like polychlorinated dibenzo-dioxin/furan congeners (PCDD/Fs) that are very toxic and are under very strict discharge regulations. Cultivating fast-growing willow shrubs, either in soil or in treatment wetlands, offers a flexible and inexpensive treatment option. The main objective of this study was to evaluate the tolerance of a frequently used willow cultivar (Salix miyabeana ‘SX67’) to irrigation with leachate contaminated with pentachlorophenol (PCP) and chromated chromium arsenate (CCA), two important wood preservatives. We designed a mesocosms experiment with willow grown in three different substrates and irrigated over 12 weeks with three different leachate concentrations. Willow proved to be tolerant to irrigation with the raw leachate, with only leaf area decreasing with increasing leachate concentration. However, the type of growing substrate influenced willow ecophysiological responses and overall performance, and seemed to affect contaminant dynamics in the plant-soil system. All contaminants accumulated in willow roots, and Cu and PCDD/Fs were also translocated to aerial parts. Overall, this study suggests that Salix miyabeana ‘SX67’ could be a good candidate for treating water or soil contaminated with wood preservatives.
显示更多 [+] 显示较少 [-]Study on Mercury Methylation in the Amazonian Rivers in Flooded Areas for Hydroelectric Use
2019
Gomes, Vinicius M. | Santos, Ademir dos | Zara, Luiz F. | Ramos, Dayana D. | Forti, Juliane C. | Ramos, Diovany D. | Santos, Felipe A.
This study aimed to estimate in laboratory the temporal production of methylmercury during the filling of reservoirs of hydropower plants and to correlate it to the ecosystem of different locations in northern Brazil: Jirau hydropower plant in the Madeira River in the state of Rondônia (white waters—under construction), Cana Brava hydropower plant in the Tocantins River in the state of Goiás (clear waters—completed), and the Negro River in the Amazon (black waters—comparative). After collecting water, soil, and sediment samples in the regions mentioned, a microcosm was created to reproduce the conditions close to those found in nature. Water/soil/Hg⁰/Hg²⁺ and water/sediment/Hg⁰/Hg²⁺ were added to glass recipients. Next, methylmercury concentration was monitored by atomic fluorescence spectrometry, total organic carbon by TOC 5000A, and physical and chemical parameters such as pH, redox potential, and dissolved oxygen, for 25 days. The results obtained allow concluding that organic matter plays an important role, providing excess methyl groups to react with inorganic Hg and form organic Hg. The Negro River, which has higher contents of organic matter in its soil, water, and sediment, presented higher potential of mercury methylation in both experiments performed, followed by rivers Madeira and Tocantins.
显示更多 [+] 显示较少 [-]Inequality of female health and its relation with urbanization level in China: geographic variation perspective
2019
Yang, Hao | Pu, Haixia | Wang, Shaobing | Ni, Runxiang | Li, Bin
Urbanization development plays a vital role in the health of modern residents; however, there have been very limited researches to specifically and comprehensively explore the relationship between urbanization level evaluating indicators (ULEIs) and female health outcomes. The mortality rate of breast cancer (BC), cervical cancer (CC), and ovarian cancer (OC) and classified urbanization factor are collected at provincial level. Stepwise regression model (SRM) and geographically weighted regression model (GWRM) are conducted to obtain spatial relationship between the mortality rate of those cancer and ULEI. Our results show that there is remarkable difference of mortality rate of BC, CC, and OC in different provinces as well as higher BC, CC, and OC distributed in northern regions. The increase of value added of primary industry (VAPI), taxi, and coal consumption has detrimental effect on BC and CC. Fuel oil consumption (FOC) ultimately results in increase of mortality rate of BC and OC, and urban fixed asset investment (UFAI) poses a risk to increase the mortality rate of OC. Contrarily, natural gas consumption (NGC) appear to mitigate mortality rate of BC. In particular, our findings demonstrate that there exist spatial differences for VAPI, FOC, NGC, taxi, and coal consumption influencing BC, CC, and OC. It is suggested that policy makers should take account of regional discrepancy and implement a sustainable urbanization development considering female health.
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