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101.
二氧化钛光催化剂的表征方法研究 总被引:10,自引:0,他引:10
光催化氧化法作为一种非常具有应用前景的有机废水处理方法而成为近年来国内外的一个热点研究领域。二氧化钛因其光催化活性高、适用范围广等优点而引起众多研究者的重视,这方面的研究已取得了许多成果。二氧化钛光催化活性的强弱直接影响到该方法在实际中的应用。本文对影响二氧化钛催化活性的因素以及表征这些因素的方法进行了评述。 相似文献
102.
SO2是产生酸雨的主要气体,其主要来源于工业燃煤锅炉。以沈阳一家电厂为例,该厂选用新型高效的喷淋泡沫脱硫除尘器对锅炉排放的SO2进行治理。进入喷淋泡沫塔前的SO2平均浓度为2780mg/m^3,经脱硫后出塔平均浓度为289.3mg/m^3,去除率为89.6%。结果表明,这种有别于传统湿法的新型高效的喷淋泡沫脱硫技术及装置具有脱硫效率高、装置占地少、运行稳定、沉淀物易于回收利用等特点,对锅炉排放的SO2进行治理是非常有效的。 相似文献
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104.
Kawamoto K Arey JS Gschwend PM 《Journal of the Air & Waste Management Association (1995)》2003,53(12):1426-1435
Expected urban air concentrations of the gasoline additive methyl tertiary butyl ether (MTBE) were calculated using volatile emissions estimates and screening transport models, and these predictions were compared with Boston, MA, area urban air measurements. The total volatile flux of MTBE into the Boston primary metropolitan statistical area (PMSA) airshed was calculated based on estimated automobile nontailpipe emissions and the Universal Quasi-Chemical Functional-Group Activity Coefficient computed abundance of MTBE in gasoline vapor. The fate of MTBE in the Boston PMSA was assessed using both the European Union System for the Evaluation of Substances, which is a steady-state multimedia box model, and a simple airshed box model. Both models were parameterized based on the meteorological conditions observed during air sampling in the Boston area. Measured average urban air concentrations of 0.1 and 1 microg/m3 MTBE during February and September of 2000, respectively, were comparable to corresponding model predictions of 0.3 and 1 microg/m3 and could be essentially explained from estimated temperature-dependent volatile emissions rates, observed average wind speed (the airshed flushing rate), and reaction with ambient tropospheric hydroxyl radical (*OH), within model uncertainty. These findings support the proposition that one can estimate gasoline component source fluxes and use simple multimedia models to screen the potential impact of future proposed gasoline additives on urban airsheds. 相似文献
105.
针对燃煤电厂汞污染物排放控制的问题, 以尿素为前驱体, 通过直接热聚合法制得绒毛状石墨相氮化碳(g-C3N4), 并用于低温条件下吸附脱除单质汞(Hg0)。利用透射电子显微镜(TEM)、X射线衍射(XRD)、氮气吸附-脱附、X射线光电子能谱(XPS)等手段对吸附剂进行表征。结果表明:未改性g-C3N4具有良好的低温脱汞活性, 在120 ℃时其脱汞效率可达84.7%;CuCl2改性可以有效提高g-C3N4的脱汞性能, 其脱汞效率在40~200 ℃范围内均可达到97%以上; 温度对吸附剂脱汞效率的影响较小。XPS表征测试结果表明, 铜离子和共价态氯原子均参与了单质汞的吸附脱除反应, Hg0被Cu2+离子和共价态Cl原子氧化成了Hg2+离子, 再吸附于g-C3N4表面而脱除。CO2、SO2和水蒸气对吸附剂脱汞效率影响较小, 但水蒸气可提高汞吸附量。 相似文献
106.
温度与时间对盐酸副玫瑰苯胺比色法检测大气二氧化硫的影响 总被引:1,自引:0,他引:1
大气中二氧化硫的检测方法常用库仑滴定法和盐酸副玫瑰苯胺比色法等。目前多数学者认为比色法操作简单、经济、精确性高,被国家定为大气监测标准分析方法。几年来,我们在冬季大气监测分析中,多次出现二氧化硫测定结果明显偏低,为寻其影响因素,作者对显色时间和温度进行了控制,获得了较满意的结果。 相似文献
107.
Meinardus HW Dwarakanath V Ewing J Hirasaki GJ Jackson RE Jin M Ginn JS Londergan JT Miller CA Pope GA 《Journal of contaminant hydrology》2002,54(3-4):173-193
Over the last few years, more than 40 partitioning interwell tracer tests (PITTs) have been conducted at many different sites to measure nonaqueous phase liquid (NAPL) saturations in the subsurface. While the main goal of these PITTs was to estimate the NAPL volume in the subsurface, some were specifically conducted to assess the performance of remedial actions involving NAPL removal. In this paper, we present a quantitative approach to assess the performance of remedial actions to recover NAPL that can be used to assess any NAPL removal technology. It combines the use of PITTs (to estimate the NAPL volume in the swept pore volume between injection and extraction wells of a test area) with the use of several cores to determine the vertical NAPL distribution in the subsurface. We illustrate the effectiveness of such an approach by assessing the performance of a surfactant/foam flood conducted at Hill Air Force Base, UT, to remove a TCE-rich NAPL from alluvium with permeability contrasts as high as one order of magnitude. In addition, we compare the NAPL volumes determined by the PITTs with volumes estimated through geostatistical interpolation of aquifer sediment core data collected with a vertical frequency of 5-10 cm and a lateral borehole spacing of 0.15 m. We demonstrate the use of several innovations including the explicit estimation of not only the errors associated with NAPL volumes and saturations derived from PITTs but also the heterogeneity of the aquifer sediments based upon permeability estimates. Most importantly, we demonstrate the reliability of the 相似文献
108.
Kwak IS Chon TS Kang HM Chung N Kim JS Koh SC Lee SK Kim YS 《Environmental pollution (Barking, Essex : 1987)》2002,120(3):671-681
Specimens of medaka (Oryzias latipes) were observed continuously through an automatic image recognition system before and after treatments of an anti-cholinesterase insecticide, diazinon (0.1 mg/l), for 4 days in semi-natural conditions (2 days before treatment and 2 days after treatment). The "smooth" pattern was typically shown as a normal movement behavior, while the "shaking" pattern was frequently observed after treatments of diazinon. These smooth and shaking patterns were selected for training with an artificial neural network. Parameters characterizing the movement tracks, such as speed, degree of backward movements, stop duration, turning rate, meander, and maximum distance movements in the y-axis of 1-min duration, were given as input (six nodes) to a multi-layer perceptron with the back propagation algorithm. Binary information for the smooth and shaking patterns was separately given as the matching output (one node), while eight nodes were assigned to a single hidden layer. As new input data were given to the trained network, it was possible to recognize the smooth and shaking patterns of the new input data. Average recognition rates of the smooth pattern decreased significantly while those for the shaking pattern increased to a higher degree after treatments of diazinon. The trained network was able to reveal the difference in the shaking pattern in different light phases before treatments of diazinon. This study demonstrated that artificial neural networks could be useful for detecting the presence of toxic chemicals in the environment by serving as in-situ behavioral monitoring tools. 相似文献
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110.
为了研究钢筋混凝土防爆墙的抗爆能力,采用有限元分析方法对不同纵向配筋率、不同高跨比、不同厚度的墙体在爆炸动态荷载作用下的动力响应进行研究,对各种不同设置的钢筋混凝土防爆墙的抗爆性能进行评估。结果表明:减小高跨比对提高钢筋混凝土防爆墙的抗爆能力最为重要,提高纵向配筋率,增加厚度都能增加防爆墙的抗爆能力。 相似文献