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231.
Defu Xu Yinjuan Wu Yingxue Li Alan Howard Xiaodong Jiang Yidong Guan Yongxia Gao 《Environmental science and pollution research international》2014,21(17):10108-10119
A surface- and vertical subsurface-flow-constructed wetland were designed to study the response of chlorophyll and antioxidant enzymes to elevated UV radiation in three types of wetland plants (Canna indica, Phragmites austrail, and Typha augustifolia). Results showed that (1) chlorophyll content of C. indica, P. austrail, and T. augustifolia in the constructed wetland was significantly lower where UV radiation was increased by 10 and 20 % above ambient solar level than in treatment with ambient solar UV radiation (p?0.05). (2) The malondialdehyde (MDA) content, guaiacol peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities of wetland plants increased with elevated UV radiation intensity. (3) The increased rate of MDA, SOD, POD, and CAT activities of C. indica, P. australis, and T. angustifolia by elevated UV radiation of 10 % was higher in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland. The sensitivity of MDA, SOD, POD, and CAT activities of C. indica, P. austrail, and T. augustifolia to the elevated UV radiation was lower in surface-flow-constructed wetland than in the vertical subsurface-flow-constructed wetland, which was related to a reduction in UV radiation intensity through the dissolved organic carbon and suspended matter in the water. C. indica had the highest SOD and POD activities, which implied it is more sensitive to enhanced UV radiation. Therefore, different wetland plants had different antioxidant enzymes by elevated UV radiation, which were more sensitive in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland. 相似文献
232.
R. S. Pelzers Q. L. Yu R. A. Mangkuto 《Environmental science and pollution research international》2014,21(19):11142-11154
This article aims to understand the radiation behavior within a photo-reactor, following the ISO 22197-1:2007 standard. The RADIANCE lighting simulation tool, based on the backward ray-tracing modeling method, is employed for a numerical computation of the radiation field. The reflection of the glass cover in the photo-reactor and the test sample influence the amount of irradiance received by the test-sample surface in the photo-reactor setup. The reflection of a white sample limits the irradiance reduction by the glass cover to 1.4 %, but darker samples can lead to an overestimation up to 9.8 % when used in the same setup. This overestimation could introduce considerable error into the interpretation of experiments. Furthermore, this method demonstrates that the kinetics for indoor photocatalytic pollutant degradation can be refined through radiation modeling of the reactor setup. In addition, RADIANCE may aid in future modeling of the more complex indoor environment where radiation affects significantly photocatalytic activity. 相似文献
233.
The quantity of vehicles has increased rapidly in recent years in China; however, the recycling of End of Life Vehicles (ELV) faces several problems and barriers including the collection difficulty and the environmental pollution caused by improper dismantling. In this paper, based on analysis of the basic situation regarding management and recycling of ELV in China, the ELV flow was introduced, and the potential ELV quantity was estimated. The current management regulations and policies were summarized, and dismantling and pollution control technologies for ELV recycling were introduced, too. It was suggested that with the rapid growth of ELV quantities, more regulations will be enacted, and the recycling network will be more effective; the dismantling technology and pollution control measures will be upgraded, and the recycling and remanufacturing industries will be more combined. The government should pay more attention to improve the management and supervision of, and encourage the development of, high level enterprises. 相似文献
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236.
Influences of adding easily degradable organic waste on the minimization and humification of organic matter during straw composting 总被引:2,自引:0,他引:2
Yi N. Shan Jin H. Chen Lei Wang Fan Li Xiao H. Fu Yi Q. Le 《Journal of environmental science and health. Part. B》2013,48(5):384-392
To find a better composting process with low greenhouse gas emission and high humus production, the effect of adding kitchen waste on reduction and humification of organic matter during straw composting was studied. Three processes were compared, consisting of different ratios of straw and kitchen waste (1:2, 1:1, and 2:1). At four time points over a 62-d incubation, the reduction and humification of compost was evaluated by measuring the total mass, carbon content, and humic material content of the compost. Treatment 1 (straw/kitchen waste ratio of 1:2) reduced the total mass of compost the most. Treatment 2 (straw/kitchen waste ratio of 1:1) reduced the total carbon content the most, reflecting the highest emission of greenhouse gas. Treatment 3 produced the most humic acid material and released the lowest amount of carbon. Hence, from the point of view of reducing greenhouse gas emissions and increasing stable organic matter such as humus and humic acid during composting, treatment #3 was optimal. The three treatments resulted in significant differences in microbial biomass and enzyme activity during composting. The highest amount of active microbial biomass was associated with the largest reduction in compost mass (treatment 1). Higher proportions of straw (treatments 2 and 3), which contains more lignin, were associated with greater β-glycosidase activity, which may generate more humus that can improve soil quality. Dehydrogenase activity seemed to be the most important microbial factor in organic carbon catabolism or humification. 相似文献
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238.
Yuyi Yang Liling Lu Fen Gao Yuhua Zhao 《Environmental science and pollution research international》2013,20(5):3232-3239
The acyl carrier protein (ACP) phosphodiesterase gene (SO 4396) of Shewanella oneidensis MR-1 which was analyzed to have azoreductase activity was heterologously expressed in Escherichia coli. The ACP phosphodiesterase was found to reach maximum enzyme velocity 220.59 U/mg, named azoreductase in this study. The azoreductase had highest specific activity (153.16 U/mg) at pH 6.5, which showed a preference for nicotinamide adenine dinucleotide (NADH) as electron donor. The phylogenetic tree analysis indicated that the azoreductase had preference for NADH and dependence for flavin mononucleotide (FMN). However, the azoreductase from S. oneidensis MR-1 still had high enzyme activity in the absence of FMN. The Mg2+ had a positive influence on the enzyme activity with 25 mM concentration, whereas Cr3+, Cd2+ usually had significantly negative effect on enzyme activity. The purified azoreductase retained nearly 100 % activity after incubating in 30 % dimethyl sulfoxide (DMSO), 30 % acetone, 30 % methanol, 20 % ethanol, 20 % isopropanol, and 10 % propanol. 相似文献
239.
Hong-Guang Guo Nai-Yun Gao Wen-Hai Chu Lei Li Yong-Ji Zhang Jin-Shan Gu Yu-Liang Gu 《Environmental science and pollution research international》2013,20(5):3202-3213
Photochemical degradation of fluoroquinolone ciprofloxacin (CIP) in water by UV and UV/H2O2 were investigated. The degradation rate of CIP was affected by pH, H2O2 dosage, as well as the presence of other inorganic components. The optimized pH value and H2O2 concentration were 7.0 and 5 mM. Carbonate and nitrate both impeded CIP degradation. According to liquid chromatography–tandem mass spectrometry analysis, four and 16 products were identified in UV and UV/H2O2 system, respectively. Proposed degradation pathways suggest that reactions including the piperazinyl substituent, quinolone moiety, and cyclopropyl group lead to the photochemical degradation of CIP. Toxicity of products assessed by Vibrio qinghaiensis demonstrated that UV/H2O2 process was more capable on controlling the toxicity of intermediates in CIP degradation than UV process. 相似文献
240.
X. Q. Liang Z. Y. Nie M. M. He R. Guo C. Y. Zhu Y. X. Chen Küppers Stephan 《Environmental science and pollution research international》2013,20(10):6972-6979
One strategy to combat nitrate (NO3-N) contamination in rivers is to understand its sources. NO3-N sources in the East Tiaoxi River of the Yangtze Delta Region were investigated by applying a 15N–18O dual isotope approach. Water samples were collected from the main channel and from the tributaries. Results show that high total N and NO3-N are present in both the main channel and the major tributaries, and NO3-N was one of the most important N forms in water. Analysis of isotopic compositions (δ 18O, δD) of water suggests that the river water mainly originated from three tributaries during the sampling period. There was a wide range of δ 15N-NO3 (?1.4 to 12.4 ‰) and a narrow range of δ 18O-NO3 (3.7 to 9.0 ‰) in the main channel waters. The δ 15N and δ 18O-NO3 values in the upper, middle, and lower channels along the river were shifted as 8.2, 3.5, and 9.5 ‰, and 9.0, 4.2, and 6.0 ‰, respectively. In the tributary South Tiao, the δ 15N and δ 18O-NO3 values were as high as 9.5 and 7.0 ‰, while in the tributaries Mid Tiao and North Tiao, NO3-N in most of the samples had relatively low δ 15N and δ 18O-NO3 values from 2.3 to 7.5 ‰ and 4.7 to 7.0 ‰, separately. Our results also suggest that the dual isotope approach can help us develop the best management practice for relieving NO3-N pollution in the rivers at the tributary scale. 相似文献