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331.
Yi Li Yuming Wang Linhua Liu Dawei Wang Wenlong Zhang 《Environmental science and pollution research international》2014,21(7):5177-5186
Characterizations of Ag/ZnO hollow sphere by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectra, and UV–vis absorption spectra have been made after its synthesis. The results showed that the composite was hollow structure with diameters of about 1–4 μm. The samples synthesized were tested and identified as silver doped ZnO, which have extended and boosted the spectral absorption. The photocatalytic activity of Ag/ZnO hollow spheres was assessed using 17α-ethinylestradiol aqueous solution under UV irradiation. It has been observed that the 17α-ethinylestradiol absorption efficiency and degradation rate is higher for Ag/ZnO hollow spheres. As reusable photocatalysts, Ag/ZnO hollow spheres which could be easily separated from a suspension will facilitate their application in wastewater treatment with enhanced photostability. 相似文献
332.
Quantifying interactions between propranolol and dissolved organic matter (DOM) from different sources using fluorescence spectroscopy 总被引:1,自引:0,他引:1
Na Peng Kaifeng Wang Guoguang Liu Fuhua Li Kun Yao Wenying Lv 《Environmental science and pollution research international》2014,21(7):5217-5226
Beta blockers are widely used pharmaceuticals that have been detected in the environment. Interactions between beta blockers and dissolved organic matter (DOM) may mutually alter their environmental behaviors. To assess this potential, propranolol (PRO) was used as a model beta blocker to quantify the complexation with DOM from different sources using the fluorescence quenching titration method. The sources of studied DOM samples were identified by excitation–emission matrix spectroscopy (EEMs) combined with fluorescence regional integration analysis. The results show that PRO intrinsic fluorescence was statically quenched by DOM addition. The resulting binding constants (log K oc) ranged from 3.90 to 5.20, with the surface-water-filtered DOM samples claiming the lower log K oc and HA having the highest log K oc. Log K oc is negatively correlated with the fluorescence index, biological index, and the percent fluorescence response (P i,n) of protein-like region (P I,n) and the P i,n of microbial byproduct-like region (P II,n) of DOM EEMs, while it is correlated positively with humification index and the P i,n of UVC humic-like region (P III,n). These results indicate that DOM samples from allochthonous materials rich in aromatic and humic-like components would strongly bind PRO in aquatic systems, and autochthonous DOM containing high protein-like components would bind PRO more weakly. 相似文献
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基于对湘潭锰矿红旗矿区土-水界面重金属污染流的采样分析,通过相关性和主成分分析法,研究了锰矿区土-水界面重金属污染流中的锰、镍、铜、锌、镉、铅重金属的来源以及同源性。结果表明:6种重金属的差异性、离散程度、变异性较大;锰—镍、锰—锌、锰—镉、锰—铅、镍—锌、铜—锌、铜—铅、锌—镉、锌—铅、铅—镉呈极显著正相关,镍与锰以外的其他重金属相关性都较低;3个主成分的贡献率分别为58.300%、16.628%、11.115%,累积贡献率达到了81.543%,并且6种重金属在主成分1的载荷非常高。结合矿区的周边环境和自身特点,表明6种重金属的主要共同来源为矿区内的矿业活动,并且工业活动、交通运输、农业活动等也对矿区造成了一定程度的重金属污染。 相似文献
335.
Kuan Lun Pan Sheng Jen Yu Shaw Yi Yan 《Journal of the Air & Waste Management Association (1995)》2014,64(11):1260-1269
Direct decomposition of N2O by perovskite-structure catalysts including La2NiO4, LaSrNiO4, and La0.7Ce0.3SrNiO4 was investigated. The catalysts were prepared by the Pechini method and characterized by x-ray diffraction (XRD), BET, scanning electron microscopy (SEM), and O2-TPD. Experimental results indicate that the properties of La2NiO4 are significantly improved by partially substituting La with Sr and Ce. N2O decomposition efficiencies achieved with LaSrNiO4 and La0.7Ce0.3SrNiO4 are 44 and 36%, respectively, at 400ºC. As the temperature was increased to 600ºC, N2O decomposition efficiency achieved with LaSrNiO4 and La0.7Ce0.3SrNiO4 reached 100% at an inlet N2O concentration of 1,000 ppm, while the space velocity was fixed at 8,000 hr?1. In addition, effects of various parameters including oxygen, water vapor, and space velocity were also explored. The results indicate that N2O decomposition efficiencies achieved with LaSrNiO4 and La0.7Ce0.3SrNiO4 are not significantly affected as space velocity is increased from 8,000 to 20,000 hr?1, while La0.7Ce0.3SrNiO4 shows better tolerance for O2 and H2O(g). On the other hand, N2 yield with LaSrNiO4 as catalyst can be significantly improved by doping Ce. At a gas hour space velocity of 8,000 hr?1, and a temperature of 600ºC, high N2O decomposition efficiency and N2 yield were maintained throughout the durability test of 60 hr, indicating the long-term stability of La0.7Ce0.3SrNiO4 for N2O decomposition.
Implications:Nitrous oxide (N2O) not only has a high global warming potential (GWP100 = 310), but also potentially destroys ozone in the stratosphere. Pervoskite-type catalysts including La2NiO4, LaSrNiO4, and La0.7Ce0.3SrNiO4 are applied for direct N2O decomposition. The results show that N2O decomposition can be enhanced as Sr and Ce are doped into La2NiO4. At 600ºC, N2O decomposition efficiencies achieved with LaSrNiO4 and La0.7Ce0.3SrNiO4 reach 100%, demonstrating high activity and good potential for direct N2O decomposition. Effects of O2 and H2O(g) contents on catalytic activities are also evaluated and discussed. 相似文献
336.
针对目前国内外垃圾渗沥液处理中存在的问题,采用电化学氧化与上流式厌氧污泥床(UASB)相结合,研究建立了对香港垃圾渗沥液的二步法处理工艺.本文着重探讨了电化学间接氧化去除渗沥液中氨氮的反应机制及主要影响因素,并通过实验找出了最佳的操作条件:入水初始 pH值为9.0;流速为0.01-0.10cm/s;CI加入量2000mg/L;电流密度 32.3mA/cm2.在此条件下,经过 6h电解后,UASB反应器出水中NH-N和COD的去除率分别达到100%和87%.对该电化学氧化过程的运行成本进行了评估. 相似文献
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338.
应用BP神经网络实现环境监测的优化布点 总被引:4,自引:0,他引:4
环境监测的合理布设关系到只有用量测点的监测数据就能客观、准确地反映区域环境的质量,采用传统的优化统计模型对监测数据进行处理一限较繁。基于人工神经网络应用于模式分类与人有适应能力强、客观性好的特点,提出将人工神经网络BP与逐步聚类分析物思想相结合,实现对环境测点的逐步聚类优选,用该方法对贵阳市1992-1993年期间的16个大气环境测占煌监测数据进行优选,得到的6个优点选点符合实际结果。 相似文献
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