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121.
Shuguang Shen Meina Li Binbin Li Zhijun Zhao 《Environmental science and pollution research international》2014,21(21):12563-12568
In order to find an effective method for treating urea wastewater, the experiments on the hydrolysis of urea in wastewater were conducted in a fixed bed reactor with different aluminas (α-Al2O3, γ-Al2O3, and η-Al2O3) as catalysts respectively in contrast with inert ceramic particle. The results indicate that the three alumina catalysts show obvious catalytic activity for urea hydrolysis at 125 °C. The order of activity is η-Al2O3?>?γ-Al2O3?>?α-Al2O3, and the activity difference increases with increasing temperature. According to the characterization results, surface acidity has little impact on the activity of catalyst. However, it was found that surface basicity of alumina catalyst plays an important role in catalytic hydrolysis of urea, and the activity of catalyst may be also influenced by the basic strength. With η-Al2O3 as catalyst, the urea concentration in wastewater is reduced to 4.96 mg/L at a temperature of 165 °C. Moreover, the η-Al2O3 shows a good stability for urea hydrolysis. The hydrolysis of urea over η-Al2O3 catalyst can evidently reduce the reaction temperature and is promising to replace industrial thermal hydrolysis process. 相似文献
122.
针对山西某煤矿高矿化度、高铁酸性矿井水除铁效果差、出水容易返色等问题,采用NaOH中和调pH、曝气及化学氧化等处理工艺进行酸性矿井水中和沉淀法除铁优化实验研究。结果表明,采用NaOH中和沉淀法除铁时,投加中和剂使出水pH达6.7以上时,出水中铁含量低于10 mg/L,满足排放要求。对于本实验废水NaOH所需投加量为2.8 g/L,铁的去除率可达到99.75%;以H2O2对原水进行氧化处理,可迅速将Fe(Ⅱ)氧化成Fe(Ⅲ),其用量与原水中Fe(Ⅱ)的含量成正比。当其用量为1.6 mL/L时,可将原水中的Fe(Ⅱ)完全转化为Fe(Ⅲ),投加中和剂使出水pH达到4.5以上时,能使出水中铁含量满足排放要求。对于实验废水所需的NaOH投加量为2.0 g/L,比直接中和沉淀所需的NaOH用量要节省28.6%。曝气处理对原水中Fe(Ⅱ)的氧化效果不明显。 相似文献
123.
Rongfei Zhang Dongsheng Jiang Liujun Zhang Yibin Cui Mei Li Lin Xiao 《Environmental science and pollution research international》2014,21(3):2141-2153
This paper's survey of the pollution of the Wujin'gang River is important because it is one of the main rivers flowing into Meiliang Bay of Lake Taihu in eastern China. Trace metals (TMs) in this paper are described according to their pollution index (P i). Cluster analysis and correlation analysis are utilized for group sites and to assess co-contamination. Toxicity effect analysis was conducted using individual sediment quality guideline quotients (SQGQs) and mean SQGQs. The results showed that sediment from the Wujin'gang River basin was affected by nutrients, heavy metals, and polycyclic aromatic hydrocarbons (PAHs), which are an essential contamination source for both Meiliang Bay and Zhushan Bay of Lake Taihu. The discharge of TMs has significant correlations to total nitrogen (TN) and total phosphorus (TP); however, no significant correlations were observed between the content of PAHs and TMs. Toxicity effect results show that sediment in the Wujin'gang River basin threatens sediment-dwelling organisms. The harmful effect was mainly caused by heavy metals especially Cd, Cr, Ni, and Cu. Sediment dredging is an effective way to control pollution from internal rivers especially for the pollution of TN and heavy metals in the Wujin'gang River basin. 相似文献
124.
Roger J. Cheng Volker A. Mohnen Thomas T. Shen Michael Current John B. Hudson 《Journal of the Air & Waste Management Association (1995)》2013,63(8):787-790
The emphasis on participate control from industrial processes has been shifted recently towards fine particulates, having diameters less than 3 microns. There exists an urgent need for more scientific information of fine particle characterization.1,2 Coal and oil fired power plants are among the largest anthropogenic point sources of particulate matter.3 Limited knowledge is available on particle size distribution and trace metal composition in power plant emissions.4-7 The morphological properties of particle emissions have been largely neglected. In this report we present some information on particle characteristics for an oil-fired and coal-fired power plant. 相似文献
125.
Qiu Ling Fang Chuanglin Shen Yuming Liu Xiaoli .Institution of Geographic Sciences Natural Resources Research Chinese Academy of Sciences Beijing China; 《中国人口.资源与环境(英文版)》2011,(4):82-89
The five central cities-Beijing,Tianjin,Shanghai,Guangzhou and Shenzhen-of the three most important strategic regions in China,namely Beijing-Tianjin-Hebei metropolitan region,the Yangtze River Delta and the Pearl River Delta,are taken as a comparative analysis on urban producer services’ competitiveness,especially focusing on the comparative advantages and disadvantages of producer services in Beijing.Firstly,based on an integrated indicator system including one objective hierarchy,four standard hierarchies and 35 indicator hierarchies,the study applies factor analysis model and analytic hierarchy process model reformed by entropy technology to measure the comprehensive competitiveness of producer services in the above five cities.Secondly,Beijing has comparative advantages of capital resource,industrial base,scientific research resource and market scale,since it takes the first place of the five cities in the comprehensive competitiveness of producer services,the competitiveness of industrial development,business environment and living environment,only inferior to Shanghai in the competitiveness of talent capital.Thirdly,Beijing has comparative disadvantages in the level of producer services development,urban innovation capability and living environment.Finally,five proposals are put forth to enhance the competitiveness of producer services in Beijing,namely perfecting the system of laws and statutes,supporting the development of industry association,implementing scientific development planning,introducing preferential fiscal and taxation policies and strengthening human capital reserve. 相似文献
126.
Quantifying air pollution attenuation within urban parks: an experimental approach in Shanghai, China 总被引:2,自引:0,他引:2
Yin S Shen Z Zhou P Zou X Che S Wang W 《Environmental pollution (Barking, Essex : 1987)》2011,159(8-9):2155-2163
Parks with various types of vegetations played an important role in ameliorating air quality in urban areas. However, the attenuation effect of urban vegetation on levels of air pollution was rarely been experimentally estimated. This study, using seasonal monitoring data of total suspended particles (TSP), sulfur dioxide (SO(2)) and nitrogen dioxide (NO(2)) from six parks in Pudong District, Shanghai, China, demonstrated vegetations in parks can remove large amount of airborne pollutants. In addition, crown volume coverage (CVC) was introduced to characterize vegetation conditions in parks and a mixed-effects model indicated that CVC and the pollution diffusion distance were key predictors influencing pollutants removal rate. Therefore, it could be estimated by regression analysis that in summer, urban vegetations in Pudong District could contribute to 9.1% of TSP removal, 5.3% of SO(2) and 2.6% of NO(2). The results could be considered for a better park planning and improving air quality. 相似文献
127.
Zhou ZF Zheng YM Shen JP Zhang LM He JZ 《Environmental science and pollution research international》2011,18(9):1644-1652
Purpose
Denitrification is an important biochemical process in global nitrogen cycle, with a potent greenhouse gas product N2O. Wastewater irrigation can result in the changes of soil properties and microbial communities of agricultural soils. The purpose of this study was to examine how the soil denitrification genes responded to different irrigation regimes. 相似文献128.
Chen D Lu J Wang H Shen Y Gong D 《Environmental science and pollution research international》2011,18(8):1405-1413
Purpose
Nonpoint sources (NPS) pollution has been an important cause for water quality impairment worldwide. To take the temporal variations of both NPS pollution and in-stream attenuation into consideration, an inverse modeling approach and the load duration curve (LDC) method were combined for variable nutrient total maximum daily load (TMDL) development. 相似文献129.
采用反相乳液聚合法以凹凸棒土为原料,合成了新型NH4+-N吸附剂淀粉-g-丙烯酸/凹凸棒土,并进行了氨氮吸附对比实验。结果表明:凹凸棒土氨氮单位吸附量为4.243 mg/g;淀粉-g-丙烯酸/凹凸棒土氨氮单位吸附量为5.301 mg/g,吸附能力比未改性的凹凸棒土提高了25%。淀粉-g-丙烯酸/凹凸棒土的氨氮吸附过程比凹凸棒土更符合Freundlich等温吸附模型。随着pH、温度的升高,凹凸棒土和淀粉-g-丙烯酸/凹凸棒土对NH4+-N吸附量逐渐增大。 相似文献
130.