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421.
Decontaminating soil organic pollutants with manufactured nanoparticles   总被引:1,自引:0,他引:1  
Organic pollutants in soils might threaten the environmental and human health. Manufactured nanoparticles are capable to reduce this risk efficiently due to their relatively large capacity of sorption and degradation of organic pollutants. Stability, mobility, and reactivity of nanoparticles are prerequisites for their efficacy in soil remediation. On the basis of a brief introduction of these issues, this review provides a comprehensive summary of the application and effectiveness of various types of manufactured nanoparticles for removing organic pollutants from soil. The main categories of nanoparticles include iron (oxides), titanium dioxide, carbonaceous, palladium, and amphiphilic polymeric nanoparticles. Their advantages (e.g., unique properties and high sorption capacity) and disadvantages (e.g., high cost and low recovery) for soil remediation are discussed with respect to the characteristics of organic pollutants. The factors that influence the decontamination effects, such as properties, surfactants, solution chemistry, and soil organic matter, are addressed.  相似文献   
422.
差分光谱仪与传统点式仪器测定环境空气质量对比研究   总被引:7,自引:0,他引:7  
本文采用差分光谱仪、传统干分析仪测量环境空气质量,对比实验结果表明:二氧化硫、二氧化氮测量结果差别很小、相关性好,具有可比性;臭氧的测量结果差别较大,但相关性好,具有可比性。二氧化硫的测量结果具有一致性;而二氧化氮、臭氧的测量结果则存在一定系统偏差。  相似文献   
423.
研究了在25℃条件下重铬酸钾对方形网纹涤Ceriodaphniaquadrangula(O,F.Muler)存活、生殖和生长的影响。急性试验求得铬铬酸钾对该僵的24h和48hBc50值分别为1.0179mg/L和0.4127mg/L;其可信限分别为0.4698一1.7180mg/L和0.1980一0.6988mg/L。慢性试验以存活、生殖和生长为毒性指标,未觉察反应浓度(NOEC)为0.0625mg/L,最低觉察反应浓度(LOEO)为0.1250mg/L,其应用系数在0.15一0.30之间。流水试验(NOEC)为0.03125mg/L,(LOEC)为0.0625mg/L,其应用系数在0.08一0.15之间。结果还表明生长是最敏感的指标。  相似文献   
424.
城市环境噪声测量中布点数的优化研究   总被引:3,自引:0,他引:3  
应用主成分分析,模糊聚类概念及动态规划方法对环境噪声测量的布点数进行优化研究。所建立的模型试用于厦门市环境噪声布点数的优化研究。  相似文献   
425.
本文介绍了利用美达棉纤维持载生物摸法处理石化废水中油的试验结果。当废水在柱内停留时间为6.3h,废水中油的处理效果是令人满意的。在同一含停留时间下入流水的CODcr从420mg/L变到1832mg/L时,出流水的CODcr在168.5mg/L以下。  相似文献   
426.
This paper reviews the current status of using remote sensing and process-based modeling approaches to assess the contemporary and future circumpolar carbon balance of Arctic tundra, including the exchange of both carbon dioxide and methane with the atmosphere. Analyses based on remote sensing approaches that use a 20-year data record of satellite data indicate that tundra is greening in the Arctic, suggesting an increase in photosynthetic activity and net primary production. Modeling studies generally simulate a small net carbon sink for the distribution of Arctic tundra, a result that is within the uncertainty range of field-based estimates of net carbon exchange. Applications of process-based approaches for scenarios of future climate change generally indicate net carbon sequestration in Arctic tundra as enhanced vegetation production exceeds simulated increases in decomposition. However, methane emissions are likely to increase dramatically, in response to rising soil temperatures, over the next century. Key uncertainties in the response of Arctic ecosystems to climate change include uncertainties in future fire regimes and uncertainties relating to changes in the soil environment. These include the response of soil decomposition and respiration to warming and deepening of the soil active layer, uncertainties in precipitation and potential soil drying, and distribution of wetlands. While there are numerous uncertainties in the projections of process-based models, they generally indicate that Arctic tundra will be a small sink for carbon over the next century and that methane emissions will increase considerably, which implies that exchange of greenhouse gases between the atmosphere and Arctic tundra ecosystems is likely to contribute to climate warming.  相似文献   
427.
32种芳香化合物的好氧生物降解性表征   总被引:6,自引:0,他引:6  
本文采用芳香化合物生物降解产生的二氧化碳量作为表征其生物降解性的指标,测定了32囊芳香化合物好氧生物降解12d产生的二氧化碳量,在此基础上提出了定性划分有机物生物降解性的标准,按照此标准对32种芳香化合物的生物降解性进行了划分;另外还探索了影响生物降解性的诸因素。  相似文献   
428.
辽东湾东部砂岸严重蚀退及其原因分析   总被引:1,自引:0,他引:1  
辽东湾东部砂岸属冰后期淤长岸。近些年来遭到强烈侵蚀。不仅岬角、平直砂岸在蚀退.连一向稳定的湾内淤长岸也在转侵后退。目前,调查区100km海岸约有2/3的岸段出现严重蚀退现象,不少岸段年蚀退率已超过6m.有的沿海公路多次内迁,引起沙滩粗化、泻湖水量加大、海水倒灌、土地咸化等一系列严重灾害。  相似文献   
429.
Interactions between organic flocculant PAN-DCD and dyes   总被引:1,自引:0,他引:1  
Yu Y  Zhuang YY  Zou QM 《Chemosphere》2001,44(5):1287-1292
Organic flocculant polyacrylonitrile-dicyandiamide (PAN-DCD) was characterized by IR, 1H NMR and 13C NMR spectra. Polar groups, such as triazine, carboxyl, amidine, carbonamide and non-polar groups, such as methylene were identified in the macromolecular chain of PAN-DCD. The flocculant effectively decolorized the examined dyes in their aqueous solutions under acid condition. By comparing the IR spectra of dyes with that of PAN-DCD and that of flocs formed, weak chemical interactions between amino in PAN-DCD side chain and sulfonic acid group in the dye molecules were observed through the formation of -NH3+ SO3(-)-, NH2+ SO3(-)- or/and =NH+ SO3(-)-. By using equilibrium dialysis technique, the hydrophobic interactions between PAN-DCD and the dyes in the binding process were also observed from the experimental results. The binding extent of PAN-DCD to dye KN-R was greater than that of MO. The addition of urea into the binding system of KN-R by PAN-DCD reduced the first binding constant K from 12.2 x 10(5) (without urea) to 3.48 x 10(5) (with urea).  相似文献   
430.
污染水中还原性指标相关性探讨   总被引:1,自引:0,他引:1  
庄源益  袁有才 《环境化学》1993,12(2):121-126
本文介绍了模拟污染水中还原性指标ARs,MRS,BPM,COD,BOD的相关性,以及它们与衡量水变黑程度色阈值之间的关系。  相似文献   
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