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31.
Yiliang HE Bin ZHAO Joseph B.HUGHES Sunh Soo HAN 《Frontiers of Environmental Science & Engineering in China》2008,2(3):326-332
The performances and kinetic parameters of Fenton oxidation of 2,4- and 2,6-dinitrotoluene (DNT) in water-acetone mixtures
and explosive contaminated soil washing-out solutions were investigated at a laboratory scale. The experimental results show
that acetone can be a significant hydroxyl radical scavenger and result in serious inhibition of Fenton oxidation of 2,4-
and 2,6-DNT. Although no serious inhibition was found in contaminated soil washing-out solutions, longer reaction time was
needed to remove 2,4- and 2,6-DNT completely, mainly due to the competition of hydroxyl radicals. Fenton oxidation of 2,4-
and 2,6-DNT fit well with the first-order kinetics and the presence of acetone also reduced DNT’s degradation kinetics. Based
on the comparison and matching of retention time and ultraviolet (UV) spectra between high performance liquid chromatography
(HPLC) and standards, the following reaction pathway for 2,4-DNT primary degradation was proposed: 2,4-DNT → 2,4-dinitro-benzaldehyde
→ 2,4-dinitrobenzoic acid → 1,3-dinitrobenzene → 3-nitrophenol. 相似文献
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Jing HUO Ye YU Ling GE Bo ZHANG Yiliang HE 《Frontiers of Environmental Science & Engineering》2015,9(2):197
C60, as one of carbon nanomaterials widely used in various fields, could be released into the water environment thus exerting some potential health risks to human beings. This work examined the behavior of aqueous stable colloidal nano-C60 (nC60) aggregates under different environmental conditions including Polyethylene glycol octylphenol ether (TX100) micelles concentration, pH, and reaction time when exposed to TX100 micelles. Results show that the nC60 aggregates became more dispersive and restored the capability of generating the singlet oxygen when exposed to TX100 micelles. With the increase of TX100 concentration, smaller average size of nC60 aggregates was observed in dynamic light scattering (DLS) analysis, the fluorescence intensity of TX100 was more quenched by nC60 aggregates, and the kinetic rate constant of generating the singlet oxygen for nC60 aggregates was improved. The mean size of nC60 aggregates in the presence of TX100 had no obvious variations when the pH ranged from 4 to 8. The longer reaction time between nC60 aggregates and TX100 led to a higher kinetic rate constant of generating the singlet oxygen. Collective data suggest that variations in physicochemical properties of nC60 aggregates are strongly dependent on the surrounding media under different environmental conditions and directly govern nC60’s transport behavior and potential toxicity. 相似文献
36.
Min ZHANG Jian LU Zhencheng XU Yiliang HE Bo ZHANG Song JIN Brian BOMAN 《Frontiers of Environmental Science & Engineering》2015,9(5):832
Polybrominated diphenyl ethers (PBDEs) have been widely used as fire-retardants. Due to their high production volume, widespread usage, and environmental persistence, PBDEs have become ubiquitous contaminants in various environments.Nanoscale zero-valent iron (ZVI) is an effective reductant for many halogenated organic compounds. To enhance the degradation efficiency, ZVI/Palladium bimetallic nanoparticles (nZVI/Pd) were synthesized in this study to degrade decabromodiphenyl ether (BDE209) in water. Approximately 90% of BDE209 was rapidly removed by nZVI/Pd within 80 min, whereas about 25% of BDE209 was removed by nZVI. Degradation of BDE209 by nZVI/Pd fits pseudo-first-order kinetics. An increase in pH led to sharply decrease the rate of BDE209 degradation. The degradation rate constant in the treatment with initial pH at 9.0 was more than 6.8 × higher than that under pH 5.0. The degradation intermediates of BDE209 by nZVI/Pd were identified and the degradation pathways were hypothesized. Results from this study suggest that nZVI/Pd may be an effective tool for treating polybrominated diphenyl ethers (PBDEs) in water. 相似文献
37.
TAYLOR Shauna M HE Yiliang ZHAO Bin HUANG Jue 《环境科学学报(英文版)》2009,21(10):1336-1341
Bacterium Providencia rettgeri YL was found to exhibit an unusual ability to heterotrophically nitrify and aerobically denitrify various concentrations of ammonium (NH4+-N). In order to further understand its removal ability, several experiments were conducted to identify the growth and ammonium removal response at different carbon to nitrogen (C/N) mass ratios, shaking speeds, temperatures, ammonium concentrations and to qualitatively verify the production of nitrogen gas using gas chromatography techniques. Results showed that under optimum conditions (C/N 10, 30°C, 120 r/min), YL can significantly remove low and high concentrations of ammonium within 12 to 48 h of growth, respectively. The nitrification products hydroxylamine (NH2OH), nitrite (NO2−) and nitrate (NO3−) as well as the denitrification product, nitrogen gas (N2), were detected under completely aerobic conditions. 相似文献
38.
We investigated the e ects of environmental factors and properties of water-stable crystal fullerene (nC60) on the uptake of nC60
by Daphnia magna based on known accumulation in our laboratory. This study was performed for seven days using di erent
environmental factors including temperature, pH, water hardness, concentration (density of particle), and particle size. Results
demonstrated that body burden of C60 increased with time in all experiments. Body burden of C60 increased with increasing
concentration and particle size, and uptake of particles >100 nm reached their maximums more quickly than those <100 nm. Under
high hardness in aqueous systems with lower pH and high temperature, uptake was higher than those under opposite conditions. Uptake
in all batch tests reached balance within five days. Both nC60 properties and environmental factors influenced uptake of nC60 by D.
magna in an aqueous system. Additionally, environmental factors may have a ected accumulation by changing nC60 properties, which
are critical to understand the accumulation of fullerenes in aqueous systems. 相似文献
39.
随着太湖流域、滇池等地蓝藻水华加剧,地表水生物毒性指标作为判断水质安全的一个重要指标,将越来越受到重视.本文通过笔者的实际工作经验出发,结合镇江某水质自动站的特点,提出一些在设备运行过程中需要注意的要点和相关建议,确保生物毒性在线监测系统更加可靠及稳定的运行,在水质在线监测预警体系中发挥更有效的作用. 相似文献
40.
Yiliang He Bin Zhao Joseph B. Hughes Sung Soo Han 《Frontiers of Environmental Science & Engineering》2008,2(3):326-332
The performances and kinetic parameters of Fenton oxidation of 2,4- and 2,6-dinitrotoluene (DNT) in water-acetone mixtures and explosive contaminated soil washing-out solutions were investigated at a laboratory scale. The experimental results show that acetone can be a significant hydroxyl radical scavenger and result in serious inhibition of Fenton oxidation of 2,4- and 2,6-DNT. Although no serious inhibition was found in contaminated soil washing-out solutions, longer reaction time was needed to remove 2,4- and 2,6-DNT completely, mainly due to the competition of hydroxyl radicals. Fenton oxidation of 2,4- and 2,6-DNT fit well with the first-order kinetics and the presence of acetone also reduced DNT’s degradation kinetics. Based on the comparison and matching of retention time and ultraviolet (UV) spectra between high performance liquid chromatography (HPLC) and standards, the following reaction pathway for 2,4-DNT primary degradation was proposed: 2,4-DNT → 2,4-dinitro-benzaldehyde → 2,4-dinitrobenzoic acid → 1,3-dinitrobenzene → 3-nitrophenol. 相似文献