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941.
942.
Dina Tan Honghu Zeng Jie Liu Xiaozhang Yu Yanpeng Liang Lanjing Lu 《环境科学学报(英文版)》2013,25(7):1492-1499
The kinetics of the degradation of trace nitrobenzene (NB) by a granular activated carbon (GAC) enhanced microwave (MW)/hydrogen peroxide (H2O2) system was studied. Effects of pH, NB initial concentration and tert-butyl alcohol on the removal efficiency were examined. It was found that the reaction rate fits well to first-order reaction kinetics in the MW/GAC/H2O2 process. Moreover, GAC greatly enhanced the degradation rate of NB in water. Under a given condition (MW power 300 W, H2O2 dosage 10 mg/L, pH 6.85 and temperature (60±5)℃), the degradation rate of NB was 0.05214 min-1 when 4 g/L GAC was added. In general, alkaline pH was better for NB degradation; however, the optimum pH was 8.0 in the tested pH value range of 4.0-12.0. At H2O2 dosage of 10 mg/L and GAC dosage of 4 g/L, the removal of NB was decreased with increasing initial concentrations of NB, indicating that a low initial concentration was beneficial for the degradation of NB. These results indicated that the MW/GAC/H2O2 process was effective for trace NB degradation in water. Gas chromatography-mass spectrometry analysis indicated that a hydroxyl radical addition reaction and dehydrogenation reaction enhanced NB degradation. 相似文献
943.
Xiaoyan Chang Dong Li Yuhai Liang Zhuo Yang Shaoming Cui Tao Liu Huiping Zeng Jie Zhang 《环境科学学报(英文版)》2013,25(4):688-697
The stability and parameters of a bio-ceramic filter for completely autotrophic nitrogen removal were investigated.The completely autotrophic nitrogen removal over nitrite(CANON) reactor was fed with different concentrations of ammonia(400,300,and 200mg N/L) but constant influent ammonia load.The results showed that the CANON system can achieve good treatment performance at ambient temperature(15-23°C).The average removal rate and removal loading of NH4+-N and TN was 83.90%,1.26kg N/(m3·day),and 70.14%,1.09kg N/(m3·day),respectively.Among the influencing factors like pH,dissolved oxygen and alkalinity,it was indicated that the pH was the key parameter of the performance of the CANON system.Observing the variation of pH would contribute to better control of the CANON system in an intuitive and fast way.Denaturing gradient gel electrophoresis analysis of microorganisms further revealed that there were some significant changes in the community structure of ammonium oxidizing bacteria,which had low diversity in different stages,while the species of anaerobic ammonium oxidizing(anammox) bacteria were fewer and the community composition was relatively stable.These observations showed that anaerobic ammonia oxidation was more stable than the aerobic ammonia oxidation,which could explain that why the CANON system maintained a good removal efficiency under the changing substrate conditions. 相似文献
944.
为了提高企业安全管理工作的有效性,提升企业安全业绩,本文结合杜邦STOP系统,从安全员的定位、职能、工作重点等几个方面探讨了改进我国企业安全员传统安全管理模式的途径,并强调指出安全员要遵循安全管理的客观规律,注重在企业安全管理工作中的正确定位与职能转变,减少安全管理过程中与员工的矛盾点,把安全工作的重点放在人身上等.通过安全员安全管理模式的改进,可以降低安全管理工作的人力资本,充分发挥安全员安全管理工作的效用,以创建优秀的企业安全文化. 相似文献
945.
Landscape planning and restoration in mine closure areas is not only an inevitable choice to sustain mining areas but also
an important path to maximize landscape resources and to improve ecological function in mine closure areas. The analysis of
the present mine development shows that many mines are unavoidably facing closures in China. This paper analyzes the periodic
impact of mining activities on landscapes and then proposes planning concepts and principles. According to the landscape characteristics
in mine closure areas, this paper classifies available landscape resources in mine closure areas into the landscape for restoration,
for limited restoration and for protection, and then summarizes directions for their uses. This paper establishes the framework
of spatial control planning and design of landscape elements from “macro control, medium allocation and micro optimization”
for the purpose of managing and using this kind of special landscape resources. Finally, this paper applies the theories and
methods to a case study in Wu’an from two aspects: the construction of a sustainable land-use pattern on a large scale and
the optimized allocation of typical mine landscape resources on a small scale. 相似文献
946.
947.
An overview of the spatial and temporal variations of the environmental accidents in China in recent years was presented in this paper using available data. The results showed that the frequency of pollution accidents was significantly decreased, from 3462 in 1990 to 462 in 2007. The water and air pollution accidents were found to be the dominant types, accounting for more than 80% of the total accidents. Considering the classification of environmental accidents at 4 scales, the general environmental accident, i.e., the least serious type, was the most frequent event, taking up 58.98% of the total pollution accidents. In addition, the distribution of environmental accidents was generally in accordance with the industrial layout in the country during the past decade. It is very important to note that the extraordinarily severe environmental accidents showed an increasing trend in underdeveloped regions, which was caused by the transfer and the development of heavy polluted industry in these areas. As to the losses of environmental accidents, the casualties presented an obvious reduction tendency, while the direct economic loss per accident tended to climb up. Furthermore, some key factors that affect the spatial and temporal tendencies of environmental accidents in China were discussed and some suggestions were put forward, hoping to shed light on environmental risk management and emergency plans making associated with environmental accidents in China. 相似文献
948.
Magnetic properties of the road dusts from two parks in Wuhan city, China: implications for mapping urban environment 总被引:2,自引:0,他引:2
Tao Yang Qingli Zeng Zhifeng Liu Qingsheng Liu 《Environmental monitoring and assessment》2011,177(1-4):637-648
Magnetic parameters and heavy metal concentrations of road dusts collected from two parks with distance about 16 km in Wuhan city, China, were measured. The Guishan Park is circled by main roads with heavy traffic, and the Moshan Park is located on the downwind hills of steelworks and a power plant. Mean values of magnetic susceptibility (??) and saturation magnetization (M s) of the dusts from the Moshan Park are 1.31 and 1.57 times those from the Guishan Park, respectively. Their magnetic mineralogy is dominated by pseudo-single domain magnetite; however, minor hematite was also identified in those from the Guishan Park. The dominant sources of non-natural magnetic particles and heavy metals were inferred as windblown emissions from the steelworks and the power plant for the Moshan Park, and road/railway traffics for the Guishan Park, respectively. Spatial variation in magnetic properties of road dust in the two parks and their different magnetic behavior propose that the magnetic measurements are sensitive to the different pollutant origins, as well as the urban environment, and that magnetic techniques have a high efficiency in mapping urban environment. Correlation between magnetic parameters and heavy metal concentrations is strongly site-specific: strong correlations were observed in the Moshan Park with correlation coefficients generally higher than 0.800, whereas correlations are poor in the Guishan Park. Therefore, it is strongly recommended that these relationships should be examined thoroughly before magnetic mapping. 相似文献
949.
Ke Xiao Jianping Deng Li Zeng Tao Guo Yan Gong Bo Yang Xu Zhao Huabo Duan 《环境科学学报(英文版)》2019,31(1):98-104
Electrolysis is a promising technology to improve sludge dewaterability efficiently with negligible environmental impact. To intensify the electrolytic efficiency, the effect of electrolytes (NaCl, Na2SO4, NaNO3, and NaClO4) on electrolysis pretreatment of municipal sludge and its mechanisms was investigated using Ti/PbO2 electrodes. The electrolytes, which enhanced the production of oxidative radicals, showed a significant synergetic effect in reducing the capillary suction time (CST) of sludge. NaCl was distinguished from the other electrolytes since it formed a large amount of active chlorine species, which oxidized the sludge cells to improve the sludge dewaterability. The surface morphologies as well as the soluble proteins and polysaccharides were analyzed to unravel the underlying mechanisms of sludge dewaterability. Additionally, an economic assessment showed that NaCl addition in the electrolysis pretreatment can be a suitable technique for enhancing municipal sludge dewaterability. 相似文献
950.
Qinjun Liang Yu Gao Zhigang Li Jiayi Cai Na Chu Wen Hao Yong Jiang Raymond Jianxiong Zeng 《Frontiers of Environmental Science & Engineering》2022,16(4):42