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Effects of coal blending in electrostatic precipitation efficiency—Inner Mongolia, China Texte intégral
2018
Qi, Liqiang | Xu, Jun | Yao, Yuan | Zhang, Yajuan
Based on this study, the Al₂O₃ content of Jungar coal ash is over 45%, and the resistivity of high-Al₂O₃ ash in Jungar reaches up to 10¹² Ω·cm. These results seriously influenced the electric characteristics of fly ash, and the collection efficiency of electrostatic precipitators (ESPs) evidently decreased. To facilitate the effective collection of fine particle in the flue gas generated before and after coal blending via ESP, the fly ash obtained from a power plant electrostatic precipitation was analyzed in terms of resistivity, size distribution, and cohesive force through a portable dust electrical resistivity test instrument, Bahco centrifuge, and a cohesive force test apparatus invented by the researchers. The mixed ratio of else coal is higher than 50%, the resistivity of the fly ash in the flue gas was lowered to approximately two orders of magnitude, and the size distribution showed an evident decrease in the PM2.5 and PM10 content in fly ash. In addition, the adhesive force and efficiency increase from 95.9 to 99.5% in the electrostatic precipitation. Therefore, the combustion of blending coal is an effective approach to improve the efficiency of ESP used to collect high-Al₂O₃ fly ash.
Afficher plus [+] Moins [-]Roles of hydrophobic and hydrophilic fractions of dissolved organic matter in sorption of ketoprofen to biochars Texte intégral
2018
Wu, Lin | Yang, Ningwei | Li, Binghua | Bi, Erping
Hydrophobic acid (HoA) and hydrophilic neutral (HiN) are two major fractions of dissolved organic matter (DOM). Their role in the sorption of ketoprofen (KTP) to wheat straw-derived biochars pyrolyzed at 300 °C (WS300) and 700 °C (WS700) was investigated to further probe the mechanisms responsible. WS700 has much higher pore volume and specific surface area (SSA) than WS300. Loading of HoA and HiN resulted in surface coverage of biochars. HoA with larger molecular size led to more pore blockage of biochars than HiN. Higher HoA binding affinity also caused a stronger competition with KTP on biochars. These factors reduced the accessibility of sorption sites for KTP, and significantly inhibited KTP sorption to biochar of lower SSA (i.e., WS300) by HoA. Water solubility (Sw) of KTP was slightly enhanced (3%) in the presence of HoA. In contrast, the presence of HiN reduced (22%) Sw of KTP. The decreased Sw of KTP by HiN exerted a more dominant influence than its competitive and loading effects, thus led to apparent enhanced sorption of KTP, especially to biochar of higher SSA (i.e., WS700). The results demonstrated the diverse effects of HoA and HiN on KTP sorption, which is helpful in understanding pharmaceutical-DOM-biochar interactions and environmental behaviors of pharmaceuticals.
Afficher plus [+] Moins [-]Utilization of freshwater mussel (Lamellidens marginalis) for the isolation of proteins through pH shift processing: characterization of isolates Texte intégral
2018
Surasani, Vijay Kumar Reddy | Mandal, Amit | Pandey, Abhed
Study was conducted to use underutilized freshwater mussel (Lamellidens marginalis) for the recovery of proteins using pH shift method and to study the functionality and characteristics of the recovered isolates. From the pH range tested (pH 2.0–13.0), maximum protein yields were obtained during solubilization at pH 2.0 and pH 13.0 (p < 0.05). During the protein recovery process, pH 13.0 was found to have minimal effect on proteins resulting in higher protein yields compared to pH 2.0. Isolates obtained by both acidic and alkaline solubilization processes had low stability and poor gel network. Total lipid content, total myoglobin, and pigment contents were reduced significantly (p < 0.05) during pH shift processing, resulting in whiter protein isolates and protein gels. All the essential amino acids were present in the isolates recovered by acid and alkaline solubilization, indicating the complete recovery of amino acids. No microbial counts were observed in any of the isolates prepared using acid and alkaline-aided processing. Acid and alkaline solubilization (pH shift) process was found to be promising for the recovery of proteins from underutilized freshwater mussel thus by reducing the supply demand gap.
Afficher plus [+] Moins [-]Pesticide dichorvos induces early solid Ehrlich tumoral development associated with a non-protective pro-inflammatory response Texte intégral
2018
de Camargo, MarcelaRodrigues | Akamine, PedroVinicius Teruya | Venturini, James | de Arruda, MariaSueli P. | da Silva Franchi, CarlaAdriene
Prolonged exposure to dichlorvos (DDVP), a common pesticide used for food crops, has been related to the development of infections and malignancies. Macrophages are used as bioindicators of immunotoxicity; thus, evaluation of their activity in solid Ehrlich tumor-bearing mice (TBM) may be useful to evaluate the influence of pesticides on human health. To investigate the effects of low DDVP doses, Swiss mice were divided into the following groups: the DDVP group, composed of mice fed diets containing 10 mg/kg of DDVP; the TBM group, consisting of mice subcutaneously inoculated with 10⁷ tumor cells/100 μl and fed a basal diet; the DDVP-TBM group, consisting of mice previously fed DDVP-containing diets for 28 days and then subcutaneously inoculated with tumor cells; and the control (CTRL) group, composed of mice fed a basal diet. After 7 and 21 days of tumor inoculation, the mice were euthanized; and after necroscopic examination, the neoplastic mass, organs, and intraperitoneal fluid were collected. Adherent peritoneal cells were cultivated to determine the production of H₂O₂ and TNF. Altogether, our results indicate that even at low doses, the intake of DDVP caused weight loss and increased tumor mass, which were associated with H₂O₂ production and high levels of TNF, a pro-inflammatory cytokine. These data are important as the exposure to pesticides, even at low doses, could potentially hinder the immune response against tumors and, consequently, create favorable conditions for their development.
Afficher plus [+] Moins [-]The impacts of the axial-to-radial airflow quantity ratio and suction distance on air curtain dust control in a fully mechanized coal face Texte intégral
2018
Wang, Hao | Cheng, Weimin | Sun, Biao | Yu, Haiming | Jin, Hu
To understand the impacts of the axial-to-radial airflow quantity ratio (denoted as R) and the suction distance (denoted as Dₛ) on air curtain dust control in a fully mechanized coal face, the 3dₒwₙ610 coal face in Jiangzhuang coal mine was numerically simulated in this study. A mathematic model was established to describe the airflow migration and dust diffusion in a coal face, and a scaled physical model was constructed. The comparison between simulation results and field measurements validated the model and the parameter settings. Furthermore, the airflow migration and dust diffusion at various R and Dₛ are analyzed using Ansys CFD. The results show that a reduction of R and Dₛ is conducive to the formation of an effective axial dust control air curtain; the dust diffusion distance decreases with the decrease of both R and Dₛ. By analyzing the simulation results, the optimal parameter for air curtain dust control in the 3dₒwₙ610 coal face and those faces with similar production conditions is determined as R = 1/9 and Dₛ = 2 m. Under the optimal parameter condition, the high-concentration dust can be confined in front of the mining driver within a space 5.8 m away from the coal face.
Afficher plus [+] Moins [-]Are shocks to renewable energy consumption permanent or temporary? Evidence from 54 developing and developed countries Texte intégral
2018
Demir, Ender | Gözgor, Giray
The renewable energy sources are considered as the important factor to decrease the level of carbon emissions and to promote the global green economy. Understanding the dynamics of renewable energy consumption, this paper analyzes whether there is a unit root in renewable energy consumption in 54 countries over the period 1971–2016. To this end, the unit root test of Narayan–Popp with two endogenous (unknown) breaks is implemented. The paper finds that renewable energy consumption series are stationary around a level and the time trend in 45 of 54 countries. In other words, renewable energy consumption follows a unit root process only in nine countries: Brazil, China, Colombia, India, Israel, Japan, the Netherlands, Spain, and Turkey. The evidence implies that renewable energy demand policies, which aimed to decrease the carbon emissions, will only have permanent effects in those nine countries.
Afficher plus [+] Moins [-]Water treatment by new-generation graphene materials: hope for bright future Texte intégral
2018
Ali, Imran | Alharbi, OmarM. L. | Tkachev, Alexey | Galunin, Evgeny | Burakov, Alexander | Grachev, VladimirA.
Water is the most important and essential component of earth’s ecosystem playing a vital role in the proper functioning of flora and fauna. But, our water resources are contaminating continuously. The whole world may be in great water scarcity after few decades. Graphene, a single-atom thick carbon nanosheet, and graphene nanomaterials have bright future in water treatment technologies due to their extraordinary properties. Only few papers describe the use of these materials in water treatment by adsorption, filtration, and photodegradation methods. This article presents a critical evaluation of the contribution of graphene nanomaterials in water treatment. Attempts have been made to discuss the future perspectives of these materials in water treatment. Besides, the efforts are made to discuss the nanotoxicity and hazards of graphene-based materials. The suggestions are given to explore the full potential of these materials along with precautions of nanotoxicity and its hazards. It was concluded that the future of graphene-based materials is quite bright.
Afficher plus [+] Moins [-]Environmental quality benchmarks—the good, the bad, and the ugly Texte intégral
2018
Chapman, PeterM.
Environmental quality benchmarks (EQBs) such as water or sediment quality guidelines comprise one line of evidence for assessing the potential harm from chemicals and other stressors (physical, biological). They are useful but not perfect tools, should not always be used, and should never be used alone for final decision-making. The “good” can be designed to be situation-specific and can provide understandable scientific input to decision-makers. The “bad” includes perception that they are absolutes (i.e., definitive binary decision points), no or limited adaptability based on good science or common sense, and protection of individual organisms not populations of organisms. The “ugly” includes benchmarks based on simplistic indices (information loss, misleading results), misuse of biomarkers, and misapplication of EQBs. Other factors to be considered include the following: appropriately deriving EQBs, uncertainty, the laboratory is not the field, contaminant uptake and cause-effect, and specifics regarding sediment quality benchmarks (i.e., their specific “good,” “bad,” and “ugly” components). EQBs are not always needed or useful.
Afficher plus [+] Moins [-]Pesticide residues in muscles of some marine fish species and seaweeds of Iskenderun Bay (Northeastern Mediterranean), Turkey Texte intégral
2018
Polat, Abdurahman | Polat, Sevim | Simsek, Ayşe | Kurt, TubaTerbiyik | Ozyurt, Gülsün
Pesticide residues in muscles of nine marine fish and four seaweed species of Iskenderun Bay (Northeastern Mediterranean) have been investigated. In sampled fish species, two herbicides, three insecticides, two fungicides, and one synergist were identified and quantified. Metribuzin DADK, propamocarb HCl, and piperonyl butoxide (PBO) were detected in all the muscles of sampled fish species. Metribuzin DADK was the most abundant pesticide residue in fish muscles and the highest metribuzin DADK concentration was found in sardine (311.20 μg/kg). Propamocarb HCl concentrations varied greatly among species; from 0.530 ± 0.020 μg/kg in striped sea bream to 34.170 μg/kg in sea bass. The level of PBO ranged from 0.001 μg/kg for fourlined terapon to 0.013 μg/kg for sardine. No measurable oxamyl residue was found in any of the muscles of sampled fish species (except sardine). In seaweeds, two herbicides and two insecticides were identified and quantified. Metribuzin DADK was the most abundant and found in Cystoseira corniculata (5.01 mg/kg), Corallina elongata (0.703 mg/kg), and Jania rubens (3.85 mg/kg). Molinate was a minor contaminant and only found in Corallina elongata (0.002 mg/kg). Pyrethrin I was determined only in Padina pavonia to be 0.567 mg/kg. Pyrethrine II was found in Padina pavonia and Corallina elongate to be 1.214 and 0.229 mg/kg, respectively. The most hazardous pesticide residues of organochlorines and organophosphorus were not detected in both sampled fish muscles and seaweeds. There are no clear maximum residue limits for the detected eight pesticide residues declared for fish muscle by European Union MRL (2017). In conclusion, it can be considered that observed concentrations of pesticides in sampled nine marine fish species do not have a potential health risk for consumers. Some of the detected pesticide residues can be toxic for algae and aquatic life and regular monitoring studies are therefore essential to control the pesticide concentrations of aquatic biota in the region.
Afficher plus [+] Moins [-]Effective removal of heavy metals by nanosized hydrous zirconia composite hydrogel and adsorption behavior study Texte intégral
2018
Yang, Jianhua | Chu, Yangyang | Li, Zhengkui | Zhang, Yipin
A novel type of adsorbent, hydrous zirconium oxide (HZO) based on polymer hydrogel (HZO-P(TAA/HEA) hydrogel), was synthesized by irradiation polymerization and in situ precipitation methods to remove heavy metals from water efficiently. The composite hydrogel was characterized using scanning electron microscope (SEM), transmission electron microscope (TEM), swelling kinetics, zeta potential, X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS). The results indicated that HZO nanoparticles were stably loaded on the P(TAA/HEA) hydrogel, swelling properties, and thermal stability were also enhanced after the loading of HZO. Besides, the batch adsorption experiments revealed that adsorption time, pH, initial concentration of heavy metals, and coexisting ions influenced the adsorption process significantly. The adsorption capacities of HZO-P(TAA/HEA) hydrogel for Pb²⁺, Cu²⁺, Cd²⁺, and Ni²⁺ was 0.620 mmol g⁻¹, 0.615 mmol g⁻¹, 0.701 mmol g⁻¹, and 0.700 mmol g⁻¹, respectively. The adsorption isotherms fitted Langmuir equation well, and the adsorption kinetics followed second-order kinetics; it was manifested that the priority of competitive adsorption followed the order: Pb²⁺ > Cu²⁺ > Ni²⁺ > Cd²⁺. Furthermore, based on the analysis results of FTIR and XPS, the adsorption mechanism could mainly be the complexation between hydrous zirconia and heavy metals. The results indicate that nanocomposite HZO-P(TAA/HEA) hydrogel is a promising heavy metal adsorbent.
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