^1^4C—样品制备方法比较研究     

李树真 《中国沙漠》1994,14(3):86-91

本文比较了防爆氧燃烧，酸性湿氧化及碱性湿氧化。结果表明，防爆氧燃烧技术有快速，安全可靠，１４Ｃ回收率高，计数体系淬灭小，不分相，计数稳定，无化学发光（ＲＣＭ％＝０）等优点，可作为１４Ｃ的常规探测法。  相似文献   

Chemical characteristics of fine particles during spring dust storm dominant period in two Chinese cities, Baotou and Wuwei     

Min HU Fan YANG Dingli YUE Song GUO Mengting WEN Wenting ZHANG Feng TIAN 《中国地球化学学报》2006,25(B08):221-221

Mineral dust, including dust storm, fugitive and floating dust are the most important components of ambient aerosol in northern China during spring. Meanwhile, it goes through heating period when fossil fuel combustion acts as a dominant source. In order to understand the chemical characteristics of fine particles in North China, two sampling sites was established in Baotou City in the west of Inner Mongolia Autonomous Region and Wuwei City near the edge of Gobi to collect fine particles （PM 2.5） samples in the spring of 2004 and 2005, and analyze mass concentrations, ionic species and some element components of PM 2.5. The results indicated that dust events elevated the mass concentrations of particulate matter significantly, not only for coarse particles, but also for fine particles. Crustal components, organic matter and sulfates are three major compositions in fine particles, their mass concentrations and relative abundances are closely related with the frequency of dust events and coal combustion. The characteristics of fine particles are obviously diverse under different atmospheric conditions. （1） When the dust storms take place, the wind speeds are often higher than 10 m/s. A plenty of mineral aerosol is input from long distance, and also local soil dust is blown up to suspend in the air as particles. Therefore, the concentrations of PM 2.5 are enhanced dramatically. Mass concentrations and relative percentages of crustal components in PM 2.5 increased significantly during dust events. The mineral dust may help gas to particle conversation by heterogeneous reactions. Increases in mass concentrations of SO4^2-, NO3^- and NH4^＋ and organic matter in PM 2.5 were observed evidently. But their fractions in PM 2.5 do not increase simultaneously due to dilution of storing wind. （2） When wind velocity is lower （〈3 m/s）, air pollutants are accumulated, both mass concentrations of SO4^2-, NO3^- and NH4^＋ and organic matter, and their fractions in PM 2.5 increase, indicating severe anthropogenic pollution. The chemical characteristics of PM 2.5 in Baotou and Wuwei are also influenced by their industrial structure, topography and meteorological conditions.  相似文献   

Votalization of selenium in selenium-rich black rock series in Yutangba     

Shujuan SHI Yuegang TANG 《中国地球化学学报》2006,25(B08):48-48

Votalization of selenium in selenium-rich black rock series in Yutangba is discussed at 400, 500, 600, 700, 800 and 900℃.Votalization of selenium tends to increase when the temperature is high. So environmental influence of selenium-rich black rock series combustion needs to be considered.  相似文献   

Study on the distribution of PAHs in fly ash from coal and residual char combustion in a pressurized fluidized bed     

Hongcang ZHOU 《中国地球化学学报》2006,25(B08):54-55

Direct coal combustion not only has a low utilizing efficiency, but also produces a large amount of pollutants such as particulate, CO2, SO2, NOx, polycyclic aromatic hydrocarbons （PAHs）, PCDD/PCDFs, and so on. Coal gasification is a clean coal technology that presents good prospects for coal use, mainly for producing electricity with a high coal conversion efficiency and low environmental impact. However, there is a problem about the minimization of PAHs in coal gasification or direct coal combustion. PAHs are harmful to the environment and human health due to their high degree of mutagenicity and carcinogenicity when they enter human bodies through breathing, eating, and drinking. It is said that about 75%-90% cancers of human beings are mainly caused by PAHs. So the US EPA has prioritized 16 PAH compounds as hazardous air pollutants; these compounds are naphthalene （NAP）, acenaphthylene （AcPy）, acenaphthene （AcP）, fluorene （Flu）, phenanthrene （PhA）, anthracene （ANT）, fluoranthene （FluA）, pyrene （Pyr）, benzo （a） anthracene （BaA）, chrysene （Chr）, benzo （b） fluoranthene （BbF）, benzo （k） fluoranthene （BkF）, benzo （a） pyrene （BaP）, indeno（1,2,3,-cd） pyrene [In（1,2,3-cd） P], dibenzo （a,h） anthracene （DbA）, and benzo （ghi） perylene （BghiP）. The residual char is one of the main products during coal gasification, and then it is brought into the combustion chamber to combust. To investigate the distribution of PAHs in fly ash, the combustion of coal and residual char was tested in a pressurized spouted fluidized bed. After Soxhlet extraction and K-D concentration, the contents of 16 PAHs recommended by US EPA in coal, residual char, and fly ash, were analyzed by a HPLC coupled with fluorescence and diode-array detection.  相似文献   

Open burning of wastes as the source of environmental contamination by POPs     

Sergey V. Kakareka Tamar I. Kukharchyk 《中国地球化学学报》2006,25(B08):177-178

In the paper the procedure for and results of a test study of a few persistent organic pollutants - polycyclic aromatic hydrocarbon （PAH）, polychlorinated biphenyls （PCB） and hexachlorobenzene （HCB） emission from the open burning of different types of wastes （domestic wastes, agricultural debris, landscape cleating debris, etc.） are discussed. The open burning of agricultural debris and landscape-clearing debris is widely applied in rural areas and small towns and in allotment gardens for the recovery of that part of wastes that can not be utilized for compost preparation. This process is most typical during the autumn season and to a lesser degree during spring. Burning occurs usually in bon fires. Burning modes differ depending on the volume of material burnt, the waste moisture content, the weather conditions, etc. During this process part of domestic wastes （polluted wood, paper, chipboard, films, plastics, etc.） are burned also. Investigations included the collection and preparation of combustible material, the simulation of open burning processes, particulate and gas emission sampling, chemical analysis of sample and data processing. Sampling procedures and sample preparation were agreeable to the emission sampling standards. The aerosol and vapour phases of POPs were collected by ordinary sampling train with pumping of waste gases through filter and solid sorbent （polyurethane foam）. For the measurements of PAH in emission, gas chromatography and mass spectrometry were used which make it possible to identify and determine 16 PAH compounds in the samples; this method was used for HCB determination also. Gas chromatography with ECD detector was used for PCB measurement. It was detected that the levels of PAH emission from wastes uncontrolled burning of wastes vary greatly. Influencing factors are composition and properties of refuse, temperature and mode of burning, level air supply. Generally, the increase of content of wood leads to the increase of PAH in emission. PAH emission also increased with increasing temperature of burning. The highest PAH values are characteristic of emissions from domestic refuse burning. Practically, all naphthalene, acenaphthylene, acenaphthene （from 60% to 100% of their total mass） and fluorene （14%-99%） were emitted in gaseous form.  相似文献   

锅炉微机智能控制系统在锅炉房设计中的应用     

邓丽娟 《中国勘察设计》2002,(4):56-57

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煤燃烧过程中微量元素的迁移和富集   总被引：5，自引：0，他引：5  

黄文辉  唐修义 《中国煤田地质》2002,14(Z1):75-87

煤中微量元素在燃烧过程中产生迁移与富集。大部分元素在煤的燃烧产物中得以富集,一些挥发性强的元素将扩散到大气中。在飞灰中,大部分环境有害元素的富集程度与其粒度成反比,即在细粒飞灰中更加富集,由此对人体健康的潜在危害也更大。在我国,大型燃煤电厂的环境问题值得重视,同时大量的民用炉灶产生的环境污染更加严重,值得进一步研究与治理。  相似文献   

Distribution of heavy metals in an incineration system of solid wastes in the Three-Gorges region of the Yangtze River   总被引：1，自引：1，他引：0  

HUANG Chuan WANG Li＇ ao CHEN Gangcai LUO Yu ZHANG Jun CUI Zhiqiang 《中国地球化学学报》2008,27(2):189-193

On the basis of investigations on the composition and contents of heavy metals in the domestic refuse in the Three-Gorges region of the Yangtze River, in combination with the experimental results, this paper deals with the distribution rule of heavy metals in the various compartments of an incineration system： leachate pool, fly ash and residue. It is concluded that in the leachate pool heavy metals should not be neglectable since about 30% of Pb and 10% of Cr are leached here; in the incineration system, above 74% of Cr, As and Pb exists in residue; above 96% of Hg exists in fly ash and the contents of Cd in fly ash are close to those of residue. It is also concluded that the physical conditions of incineration have a significant influence on the distribution of heavy metals in the incineration system.  相似文献   

硫铁矿焙烧灰渣中铊分布规律及环境效应的研究   总被引：6，自引：0，他引：6  

谢文彪  陈永亨  陈穗玲  毕雪贞  范小苑 《矿物岩石地球化学通报》2000,19(3):204-206

利用分光光度法测定了铊在硫铁矿焙烧灰、渣中的含量,探讨了含铊硫铁矿燃烧后铊在灰渣中的集散规律及其对环境影响。结果显示硫铁矿焙烧灰渣中铊含量远高于克拉克值和土壤背景值;与原矿石相比,铊在炉灰中富集,炉渣中含量减少。硫铁矿燃烧产生的含铊灰渣对环境危害增大。  相似文献   

海水中胶体有机碳的测定──高温燃烧法和紫外/过硫酸钾法的比较   总被引：5，自引：0，他引：5  

王江涛  赵卫红  谭丽菊  张正斌 《海洋学报》2000,22(2):65-70

利用切向超滤(cross-flow ultrafiltration)技术对海水中胶体有机碳(COC)和真溶解有机碳(UOC)进行了分离,并分别用高温燃烧法和紫外/过硫酸钾法对胶体有机碳和真溶解有机碳进行了测定。测定结果表明,切向超滤能定量分离海水中的胶体有机碳,高温燃烧法和紫外/过硫酸钾法对胶体有机碳和真溶解有机碳的测定结果没有明显的系统误差,表明这两种方法的氧化效率基本相同,胶体粒子的存在,对紫外/过硫酸钾法的氧化效率没有显着影响。  相似文献