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以南京江北新区分流制雨水管道沉积物为研究对象,考察不同粒径沉积物中铵态氮(NH3-N)和硝态氮(NO3--N)干期分布特征,分析其随干期长度的变化关系,并探讨沉积物理化性质及微生物菌群结构对NH3-N和NO3--N干期分布的影响.结果表明:粒径≤0.075mm的沉积物中NH3-N占比最高(交通区30.8%,商业区36.7%);交通区粒径≤0.075mm的沉积物中NO3--N占比最高(33.0%),而商业区粒径0.075~0.15mm沉积物中NO3--N占比最高(34.4%);干期长度与交通区0.075~0.15mm粒径段的沉积物中NO3--N含量及商业区粒径≥0.3mm的沉积物中NH3-N含量之间的相关性均最显著;雨水管道沉积物中NH3-N和NO3--N的干期分布与O-H和N-H等官能团、表面极性和亲水性、微观形貌等有一定关联;交通区雨水管道沉积物中Gemmobacter等反硝化优势菌种(相对丰度总和为20.15%)对NO3--N干期分布影响更显著. 相似文献
23.
Peng Du Jianguo Liu Huaqiao Gui Jiaoshi Zhang Tongzhu Yu Jie Wang Yin Cheng Yihuai Lu Yawei Yao Qiang Fu ChihChieh Chen 《环境科学学报(英文版)》2020,32(1):238-249
PM_(2.5) separator directly affects the accuracy of PM_(2.5) sampling.The specification testing and evaluation for PM_(2.5) separator is particularly important,especially under China's wide variation of terrain and climate.In this study,first a static test apparatus based on polydisperse aerosol was established and calibrated to evaluate the performance of the PM_(2.5) separators.A uniform mixing chamber was developed to make particles mix completely.The aerosol concentration relative standard deviations of three test points at the same horizontal chamber position were less than 0.57%,and the particle size distribution obeyed logarithmic normal distribution with an R~2 of 0.996.The flow rate deviation between the measurement and the set point flow rate agreed to within ± 1.0% in the range of -40 to 50℃.Secondly,the separation,flow and loading characteristics of three cyclone separators(VSCC-A,SCC-A and SCC112) were evaluated using this system.The results showed that the 50% cutoff sizes(D_(50)) of the three cyclones were 2.48,2.47 and 2.44 μm when worked at the manufacturer's recommended flow rates,respectively.The geometric standard deviation(GSD) of the capture efficiency of VSCCA was 1.23,showed a slightly sharper than SCC-A(GSD = 1.27),while the SCC112 did not meet the relevant indicator(GSD = 1.2 ± 0.1) with a GSD = 1.44.The flow rate and loading test had a great effect on D_(50),while the GSD remained almost the same as before.In addition,the maintenance frequency under different air pollution conditions of the cyclones was summarized according to the loading test. 相似文献
24.
Because of its significant toxicological effects on the environment and human health,arsenic(As) is a major global issue.In this study,an Fe-based metal-organic framework(MOF)(Materials of Institut Lavoisier:MIL-100(Fe)) which was impregnated with reduced graphene oxide(rGO) by using a simple hydrothermal method and coated with birnessitetype manganese oxide(δ-MnO_2) using the one-pot reaction process(MIL-100(Fe)/rGO/δ-MnO_2 nanocomposites) was synthesized and applied successfully in As removal.The removal efficiency was rapid,the equilibrium was achieved in 40 min and 120 min for As(Ⅲ) and As(Ⅴ),respectively,at a level of 5 mg/L.The maximum adsorption capacities of As(Ⅲ) and As(Ⅴ) at pH 2 were 192.67 mg/g and 162.07 mg/g,respectively.The adsorbent revealed high stability in pH range 2-9 and saturated adsorbent can be fully regenerated at least five runs.The adsorption process can be described by the pseudo-second-order kinetic model and Langmuir monolayer adsorption.The adsorption mechanisms consisted of electrostatic interaction,oxidation and inner sphere surface complexation. 相似文献
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From 2000 to 2010 China experienced rapid economic development and urbanization. Many cities in economically developed areas have developed from a single-center status to polycentricity. In this study, we used exploratory spatial data analysis (ESDA) to identify the population centers, which identified 232 cities in China as having urban centers. COMP was used to represent urban agglomeration, and POLYD (representing how far is the city's sub-centers to the main center), POLYC (representing the number of a city's centers), and POLYP (representing the population distributed between the main center and the sub-centers) were used to indicate urban polycentricity. Night light data were used to determine the CO2 emissions from various cities in China. A mixed model was used to study the impact of urban aggregation and polycentric data on the CO2 emission efficiency in 2000 and 2010. The study found that cities with higher compactness were distributed in coastal areas, and the cities with higher multicentricity were distributed in the Yangtze River Delta and Shandong Province. The more compact the city was, the less conducive it was to improving CO2 emission efficiency. Polycentric development of the city was conducive to improving the CO2 emission efficiency, but the number of urban centers had no significant relationship with the CO2 emission efficiency. Our research showed that the compactness and multicentricity of the city had an impact on the CO2 emission efficiency and provided some planning suggestions for the low carbon development of the city. 相似文献
28.
Long Xingle Sun Chuanwang Wu Chao Chen Bin Boateng Kofi Agyenim 《Mitigation and Adaptation Strategies for Global Change》2020,25(7):1243-1260
Mitigation and Adaptation Strategies for Global Change - Considering government and market failure of environmental regulation to combat increasing GHG (greenhouse gas) emissions, green innovation... 相似文献