Raman and SERS spectra of thiamethoxam and the Ag3–thiamethoxam complex: an experimental and theoretical investigation

Dutch water boards have a well-established program for monitoring pesticide contamination of surface waters. These monitoring data have been processed into a graphic format accessible online and designed to provide insight into pesticide presence in Dutch surface waters and trends over time: the Pesticides Atlas (http://www.pesticidesatlas.nl). With this tool one can easily get maps of where a pesticide is being measured and where it might possibly constitute an environmental problem over the years. Presently, results of the periods 1997/1998 until 2005/2006 are available at the level of individual active ingredients. At a national level, the percentage of pesticides concentrations that exceed the maximum tolerable risk has declined 30% to 38% over the years 2003/2004 compared with 1997/1998. This means that surface water quality in the Netherlands has improved with respect to pesticides, however there are still many locations at which the measured concentrations exceed the environmental quality standards. The results on linking land use to pesticides concentrations were shown to assist in optimization of monitoring programs. By developing the present Internet tool, many new opportunities for environmental risk assessment and risk management were identified, e.g. optimization of monitoring strategies and communication to policymakers.     

三维荧光区域积分评估城市污水中溶解性有机物去除

以三维荧光技术为手段,结合荧光区域积分和聚类分析,考察某城市污水厂污水处理过程中溶解性有机物的去除状况。研究结果表明,采用三维荧光区域积分可以表征城市污水中易降解、可降解和难降解有机物相对含量的变化趋势,能够有效识别污水中溶解性有机物的指纹特征。城市污水中类蛋白等易降解物质含量约占总荧光物质的50%,在污水厂曝气池缺氧段,易降解基质被大量去除。曝气池顺水流方向约225 m处,溶解性有机物的去除已基本完成。三维荧光光谱中区域II和III的积分标准体积与TOC的皮尔森相关指数分别为0.964和0.970。和其他荧光指数相比,这2个区域的积分标准体积与TOC的相关度更高。     

浓硫酸低温分解废弃稀土抛光粉工艺研究

采用浓硫酸低温分解回收废弃稀土抛光粉,考察了硫酸用量、分解温度和反应时间对分解效果的影响,结果显示,较佳实验条件下,稀土收率可达95%以上。通过热重-差热与红外光谱联用技术实时在线监测技术,表明分解过程分为2个阶段,分别在270℃和300℃温度范围附近,稀土氧化物和稀土氟氧化物与硫酸发生反应。     

Distribution and seasonal variability of trace elements in atmospheric particulate in the Venice Lagoon

Size distribution and selected element concentrations of atmospheric particulate matter (PM) were investigated in the Venice Lagoon, at three sites characterised by different anthropogenic influence. The PM₁₀ samples were collected in six size fractions (10-7.2, 7.2-3.0, 3.0-1.5, 1.5-0.95; 0.95-0.49 and <0.49 μm) with high volume cascade impactors, and the concentration of 17 elements (Al, As, Ca, Cd, Co, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sr, V, Zn) was determined by inductively coupled plasma quadrupole mass spectroscopy. More than 1 year of sampling activities allowed the examination of seasonal variability in size distribution of atmospheric particulates and element contents for each site.At all the stations, particles with an aerodynamic diameter <3 μm were predominant, thus accounting for more than 78% of the total aerosol mass concentration. The highest PM₁₀ concentrations for almost all elements were found at the site which is more influenced by industrial and urban emissions. Similarity in size distribution of elements at all sites allowed the identification of three main behavioural types: (a) elements found mainly within coarse particles (Ca, Mg, Na, Sr); (b) elements found mainly within fine particles (As, Cd, Ni, Pb, V) and (c) elements with several modes spread throughout the entire size range (Co, Cu, Fe, K, Zn, Mn).Factor Analysis was performed on aerosol data separately identified as fine and coarse types in order to examine the relationships between the inorganic elements and to identify their origin. Multivariate statistical analysis and assessment of similarity in the size distribution led to similar conclusions on the sources.     

化学发光法和DOAS测定NOx的对比研究

分析了化学发光法和差分吸收光谱法(DOAS)测定环境中氮氧化物的原理及相应分析仪器的系统结构,指出了化学发光法氮氧化物分析仪的技术瓶颈及差分吸收光谱法的难点和关键技术。并对两种方法的优缺点及发展趋势进行分析。实验表明,化学发光法与差分吸收光谱法测定的结果具有很好的相关性。     

进口含锌物料的表征和鉴别

采用X射线荧光光谱(XRF)、X射线衍射光谱(XRD)等分析手段,对4种进口疑似固体废物的含锌物料进行了表征。通过分析含锌物料的主要元素组成、物相组成和常规理化特征,结合外观特征,与含锌矿物、含锌产品及相关文献资料等进行比对,推导出含锌物料的产生来源。然后,参照我国《进口废物管理目录》得出鉴别结论。结果表明:4种含锌物料分别为锌矿、湿法冶炼锌浸出渣、热镀锌灰和固定CO2产物;后3种属于我国目前禁止进口的固体废物。     

Laser cleaning of historical limestone buildings in Bordeaux appraisal using cathodoluminescence and electron paramagnetic resonance

BACKGROUND: Most historical buildings in Bordeaux city are made of limestone. This yellowish-white rock is rather porous and highly sensitive to pollution. As a consequence of local weathering conditions, these buildings present a dark appearance due to the development of a superficial dark grey to black crust. METHODS: For the last decade, a campaign has been underway to clean these buildings. Eleven techniques of surface treatment have been used, including laser beam technology. As a contribution to the study of laser beam effects on stone buildings, two analytical methods have been used on clean versus unclean surfaces: Cathodoluminescence (CL) and Electron Paramagnetic Resonance (EPR), in addition to SEM-EDX and XRD. RESULTS: The black crust is composed of different types of particles: carbon porous micro-particles of industrial origin, atmospheric dust due to the erosion of soils and rocks, alumino-silicate particles from urban pollution; all these particles being cemented by gypsum. DISCUSSION: As far as heritage conservation is concerned, the laser surface treatment not only preserves the original patina of the stone, but also leaves surface smoothness unaltered. CONCLUSIONS AND PERSPECTIVES: CL and EPR data confirm that lasers--with highly controlled parameters--only get rid of the black crust and, thus, reveal the underneath layer, the so-called patina. This patina shows no luminescence, whereas the limestone on which it has grown shows a bright orange emission of CL. This indicates CL to be a fast and easy way to provide a high quality control for the restoration of polluted ancient stones.     

有机/无机缓蚀剂在模拟混凝土孔隙液中对钢筋缓蚀作用对比研究

目的 检测和评价五种有机/无机缓蚀剂在含3.5％NaCl的模拟混凝土孔隙液(SCP)中对Q235碳钢的缓蚀效果.方法 采用动电位极化曲线和电化学交流阻抗谱(EIS)测试方法 .结果 综合评价后可知,0.0015 mol/L的D-葡萄糖酸钠具有最好的缓蚀效果,浸泡30 d后的Rct可达到282.74×104?·cm2,此...     

X射线荧光分析法及其在环境监测中的应用

综述了X射线荧光分析法在水质分析和大气颗粒物分析中的应用,介绍了粉状固态物、液体、气体等环境试样的制备方法,以及标准曲线法、标准加入法、内标法、散射线监控法、稀释法等定量分析方法,指出X射线荧光分析法前处理简单,分析精度高,操作简便、快速．在环境监测领域具有广阔的发展前景。     

超细Ce0.5Zr0.5O2的制备及其催化甲烷燃烧性能研究

以共沉淀法制备Ｃｅ－Ｚｒ－Ｏ固溶体,在液相反应阶段、干燥阶段和灼烧阶段分别采取快速喷射和加入表面活性剂、正丁醇共沸蒸脱水以及选择适当灼烧温度等手段控制团聚体的生成,制得超细颗粒Ｃｅ０．５Ｚｒ０．５Ｏ２固溶体。