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321.
以市政供水管网钢管管垢为研究对象,将垢层由外向内分为表层、硬壳层和疏松多孔层.利用SEM、BET、XRD、XPS和分形态提取等技术对预吸附Cr(Ⅵ)前后的各层管垢进行表征和分析,并探究了pH值、SO42-浓度和温度对各层管垢中Cr释放的影响.结果显示,钢管各层管垢的主要成分均为α-FeOOH,吸附性能排序为表层>疏松多孔层>硬壳层,管垢中铁元素大多以三价和二价形式存在,具有一定还原性.Cr(Ⅵ)通过物理和化学吸附富集于管垢,主要以铁锰氧化物结合态存在,表层管垢富集量最大.酸性环境、SO42-浓度和温度的升高均会促进Cr的释放.强酸性条件下表层Cr释放浓度为中性条件下的2.76倍;SO42-浓度增加使各层管垢的Cr释放量增加0.1~0.4倍;温度升高20℃,表层管垢的Cr释放量增加26.74%. 相似文献
322.
323.
Jie Liu Junjun Ma Weizhang Zhong Jianrui Niu Zaixing Li Xiaoju Wang Ge Shen Chun Liu 《Frontiers of Environmental Science & Engineering》2023,17(4):51
324.
Yi-Jian Feng Yu-Qiang Yang Chi Zhang Er-Xi Song Dong-Sheng Shen Yu-Yang Long 《Waste management (New York, N.Y.)》2013,33(5):1073-1078
Residues from the imported wastes dismantling process create a great burden on the ambient environment. To develop appropriate strategies for the disposal of such residues, their characteristics were studied through background value analysis and toxicity leaching tests. Our results showed that the heavy metals concentrations in residues were high, particularly those of Cu (7180 mg kg?1), Zn (2783 mg kg?1), and Pb (1954 mg kg?1). Toxicity leaching tests revealed a high metal releasing risk of such residues if they are disposed of in a landfill. However, the residues of imported wastes were also found to have some intrinsic metal recycling value. 相似文献
325.
含油污泥的处理与利用 总被引:12,自引:1,他引:12
石油开采和加工过程中产生的含油污泥,带有有害物质和较高的热值,既需处理又可综合利用,这是一个复杂而又重要的课题。当前,我国含油污泥处理与利用和国外先进水平有较大差距,处理装置技术落后,不配套,多数污泥未进行无害化处理,造成了环境污染和能源资源的浪费。在收集了大量资料的基础上,列举了含油污泥的性质及危害。“九五”期间应积极开展先进工艺设备的引进推广工作,特别在含油污泥的脱水干燥、污油回收和绿化利用上,可推广江汉、中原油田的先进工艺设备,使含油污泥达到无害化乃至变废为宝。 相似文献
326.
本文系统分析现代灾害的特点;评述灾害研究及灾害学的历史与现状,预测其发展趋势;探讨灾害学的基本范畴,界定其学科体系的总体框架,对灾害研究及灾害学发展中的几个重要问题提出认识与建议。 相似文献
327.
328.
Thomas T. Shen 《The Environmentalist》1984,4(4):317-321
Summary The author was a consultant, assigned from the United Nations Development Programme (UNDP), to provide technical assistance
to China's environmental pollution research and control. His assignment in China from September 1 through October 8, 1983
was filled with visits and meetings at key research institutes, universities, and regulatory agencies in the cities of Beijing
(Peiking), Shanghai, Hangchow, Zhuji and Zhiaxing (Fig. 1). Trips to famous historical sites and scenic points in and around
those cities were squeezed in between the heavily scheduled meetings.
Dr Shen was born and educated in China through college. This is a report of his first trip back to his homeland since he left
35 years ago. His ability to communicate with the Chinese professionals and social strata in their native tongue provided
him with a greater advantage in understanding the current status of China's environmental sciences and technology in preventing
air, water, and land pollution. His contribution lies not only in the technical transfer of environmental sciences and engineering,
but also in strengthening the ties of cooperation and communication between American and Chinese professionals. Dr Shen is
a senior research scientist with the New York State Department of Environmental Conservation and an adjunct faculty member
of the Division of Environmental Sciences, Columbia University. 相似文献
329.
Size distribution and diurnal and seasonal trends of ultrafine particles in source and receptor sites of the Los Angeles basin 总被引:4,自引:0,他引:4
This paper presents results from a study conducted in two urban areas of southern California, Downey and Riverside, to examine the effect of different sources and formation mechanisms on the size distribution and temporal trends of ultrafine particles. Near-continuous data were collected for 5 months at each location. Our data clearly identified Downey as a source site, primarily affected by vehicular emissions from nearby freeways, and Riverside as a receptor site, where photochemical secondary reactions form a substantial fraction of particles, along with local vehicular emissions. In Downey, the diurnal trends of total particle number concentration and elemental carbon (EC) appear to be almost identical throughout the day and irrespective of season, thereby corroborating the role of primary emissions in the formation of these particles. This agreement between EC and particle number was not observed in Riverside during the warmer months of the year, while very similar trends to Downey were observed during the winter months in that area. Similarly, the size distribution of ultrafine particles in Downey was generally unimodal with a mode diameter of 30-40 nm and without significant monthly variations. The number-based particle size distributions obtained in Riverside were bimodal, with a significant increase in accumulation mode as the season progressed from winter to summer. During the warmer months, there was also an increase in sub-100-nm particles in the afternoon hours, between 2:00 p.m. and 4:00 p.m., that also increased with the temperature. The differences observed in the ultrafine particle distribution and temporal trends clearly demonstrated that mechanisms other than direct emissions play an important role in the formation of ultrafine particles in receptor sites of the Los Angeles Basin. 相似文献
330.
关于重大隐患监控GIS模式的研究 总被引:3,自引:3,他引:3
沈立 《中国安全科学学报》2002,12(5):1-4
系统地分析了重大危险源、事故隐患的地域监管体系以及隐患监控的新技术应用基础 ;提出了职业安全卫生监管体系中的危险源和隐患监控 ,应该分为过程安全监控和安全目标监控两个层次。隐患监管功能的有效实现 :隐患监控的技术载体则越来越依托信息网络的发展 ;重大隐患监管体系特别适合采用地理信息系统 相似文献