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941.
Jiang W Zhang S Shan XQ Feng M Zhu YG McLaren RG 《Environmental pollution (Barking, Essex : 1987)》2005,138(2):278-284
Laboratory batch experiments were carried out to study the adsorption of arsenate on 16 Chinese soils with different physicochemical properties. Wide differences in arsenate adsorption were observed, and the Jiangxi and Hubei soils were more effective sorbents for arsenate than other soils. The Langmuir one-surface and two-surface equations were used to model the arsenate adsorption data. Except for the Jiangxi and Hubei soils, the Langmuir one-surface equation gave reasonably good fits to the arsenate adsorption data. However, the Langmuir two-surface equation generally provided a better fit than the Langmuir one-surface equation. For soils with relative high organic matter (OM), dissolved organic carbon (DOC) or extractable phosphate, the Langmuir one-surface and two-surface equations described the adsorption isotherms similarly. In contrast, for soils with relatively low contents of OM, DOC or extractable phosphate, the Langmuir two-surface equation gave the better fit to the arsenate adsorption data. 相似文献
942.
Determination of polybrominated diphenyl ethers in soil and sediment from an electronic waste recycling facility 总被引:6,自引:0,他引:6
In this study samples of ten species of fish were analyzed for concentrations of organochlorine pesticides, PCBs and heavy metals (Pb, Cd, and Cu). Fish were captured using electric fishing on ten sites along the Dr?me river (Rh?ne-Alpes region). Quantitative determination of the organochlorine and PCBs compounds was performed by gas chromatography-electron-capture detection (GC-ECD). The concentrations of heavy metals were determined by atomic absorption spectrophotometry. Samples contained detectable concentrations of lindane, PCBs, and heavy metals but at concentrations below the maximum residue limit (MRL). Non-parametric statistical analysis was performed to distinguish groups of sites with different levels of contamination. PCBs concentrations increased along the river with four groups of sites significantly different from each other. Cadmium concentrations were below the MRL. Lead contamination showed two groups significantly different and a repartition similar to PCBs. Copper contamination was correlated with the localization of vineyards. We assessed the potential effects of contamination the otter (Lutra lutra). The concentrations of all pollutants analyzed in fish sampled in this study are lower than the threshold values described in literature. The Dr?me river is relatively unpolluted river, and the establishment of otter populations should not be affected by pollution. 相似文献
943.
According to the theory of photocatalysis, the efficiency of photocatalysis decreases mostly due to the recombination of photo-generated electron-hole pairs. An electric field across a photocatalyst can promote the separation of photo-generated electrons and holes and prevent them from recombination so as to enhance the efficiency of photocatalysis. And the synergetic decomposition efficiency of photocatalysis and an electric field is greater than that of the simple combine of their single efficiency. The performance of photocatalysis enhanced by electric field (PEEF) and operating conditions such as the direction of the electric field, the voltages between the two electrodes, the material of the electrodes, which may affect the efficiency of PEEF, were investigated in this paper. The results indicate that the system of PEEF abides the established theory of photocatalysis. 相似文献
944.
直接过滤-臭氧-生物活性炭工艺用于城市污水二级处理出水深度处理的研究 总被引:2,自引:0,他引:2
采用砂滤-臭氧-生物活性炭工艺在北京市某污水处理厂开展了以污水再生回用为目的的城市污水深度处理中试研究。在臭氧消耗量5mg/L,接触时间20min,生物活性炭空床停留时间(EBCT)为20min的条件下,出水浊度为1.5NTU左右,色度接近0,UV254从0.162cm^-1降低到0.08cm^-1,DOC和CODMn分别从10.1mg/L和12.8mg/L降低到6mg/L左右。由于对生物活性炭柱进行了曝气供氧,NH4^- N从40mg/L降低到5mg/L左右。 相似文献
945.
在空气气氛下,对医疗废物中几种有代表性的有机质进行非等温热解实验。分析实验结果发现,热解失重曲线与N2气氛下不同,出现多个DTG峰。利用Freeman—CarroⅡ法求出了各有机质的表观动力学参数,并建立了能较好反映各物料失重过程的表观多步反应动力学模型。针对混合物料无法直接求出表观动力学参数,建立了多组分反应动力学模型。 相似文献
946.
针对现有水环境治理装备设计开发技术存在的不足,提出了一种融合全相关技术与CAD、CAE、CAM、CAPP技术的集成一体化装备系统设计开发方案,并给出了这种集成全相关技术的初步实现方法,而且进行了射流曝气器的设计应用。这种方法有望实现水环境治理装备系统完整、可靠的设计,并缩短了设计开发周期。 相似文献
947.
Jiang P Lignell DO Kelly KE Lighty JS Sarofim AF Montgomery CJ 《Journal of the Air & Waste Management Association (1995)》2005,55(4):437-445
Over the past several years, numerous studies have linked ambient concentrations of particulate matter (PM) to adverse health effects, and more recent studies have identified PM size and surface area as important factors in determining the health effects of PM. This study contributes to a better understanding of the evolution of particle size distributions in exhaust plumes with unconfined dilution by ambient air. It combines computational fluid dynamics (CFD) with an aerosol dynamics model to examine the effects of different streamlines in an exhaust plume, ambient particle size distributions, and vehicle and wind speed on the particle size distribution in an exhaust plume. CFD was used to calculate the flow field and gas mixing for unconfined dilution of a vehicle exhaust plume, and the calculated dilution ratios were then used as input to the aerosol dynamics simulation. The results of the study show that vehicle speed affected the particle size distribution of an exhaust plume because increasing vehicle speed caused more rapid dilution and inhibited coagulation. Ambient particle size distributions had an effect on the smaller sized particles (approximately 10 nm range under some conditions) and larger sized particles (>2 microm) of the particle size distribution. The ambient air particle size distribution affects the larger sizes of the exhaust plume because vehicle exhaust typically contains few particles larger than 2 microm. Finally, the location of a streamline in the exhaust plume had little effect on the particle size distribution; the particle size distribution along any streamline at a distance x differed by less than 5% from the particle size distributions along any other streamline at distance x. 相似文献
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