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。     

活化粉煤灰的结构和组成研究

用化学分析、x光电子能谱、波谱、热谱和扫描电子显微镜等多种方法综合研究粉煤灰的体相和表面相的化学组成、颗粒形貌、表面价态、键型和表面相变过程等结构特征。发现粉煤灰的内部组成与表面组成明显不同;颗粒以微珠为主;粒度分布接近高斯分布;表面有Si－O－Si键,而无羟基;粉煤灰加热时有吸热和放热过程发生,并伴有失重现象。这些为粉煤灰的表面改性和综合利用提供了科学依据。     

Analysis for Chemical Characterization of Atmospheric Aerosols Application of X-ray Microprobe System and Double Thin Film Method

The X-ray microprobe system was applied to ultra trace characterization of single Kosa aerosols and non-Kosa aerosols simultaneously collected at Yasaka, Japan and TaeAnn, Korea. We demonstrated remarkable mass increase of heavy metals as well as soil components in individual particles during the Kosa event compared with the non-Kosa period at Yasaka. Backward trajectory analysis suggested that the Kosa samples were in the mixing state of mineral components and anthropogenic heavy elements. Double thin film method was applied to investigate the seasonal change of the mixing states of single sea-salt aerosols associated with chlorine loss due to the heterogeneous reactions between sea-salt particles and acidic gases. It was revealed that the percentages of both chloride-nitrate mixed particles and sulfate-nitrate ones were larger in wintertime than those in summertime and fraction of chloride-nitrate mixed particles increased with an increase of particle size. Comparison between the size-segregated bulk analysis and the single particle analysis demonstrated that remarkable chloride depletion occurred in coarse particles sampled on May in the former analysis, while chloride depletion in coarse particles was not marked in the latter analysis. The discrepancy attributes to the difference of the sampling time between both analyses because significant change of air mass route occurred during the bulk sampling after completion of the single particle sampling.     

能量色散X射线荧光光谱法测定土壤和沉积物中稀土元素

建立了偏振能量色散X射线荧光光谱法测定土壤和沉积物中稀土元素的方法,该方法较传统的方法具有前处理简单、测量自动化程度高、灵敏度高和检出限低(检出限范围为0.05~2.80 mg/kg)等优点。对土壤和沉积物标准物质的测定结果表明:测定结果与认定值能较好吻合,相对标准偏差范围为0.2%~9.4%,能满足测试的需求。分别用该方法和电感耦合等离子体质谱法对实际样品进行测定,2种方法的测定结果有较好的一致性,表明该方法测定结果准确可靠,可用于实际样品的测定。     

Simulation and source identification of X-ray contrast media in the water cycle of Berlin

This article describes the development of a model to simulate the fate of iodinated X-ray contrast media (XRC) in the water cycle of the German capital, Berlin. It also handles data uncertainties concerning the different amounts and sources of input for XRC via source densities in single districts for the XRC usage by inhabitants, hospitals, and radiologists. As well, different degradation rates for the behavior of the adsorbable organic iodine (AOI) were investigated in single water compartments. The introduced model consists of mass balances and includes, in addition to naturally branched bodies of water, the water distribution network between waterways and wastewater treatment plants, which are coupled to natural surface waters at numerous points. Scenarios were calculated according to the data uncertainties that were statistically evaluated to identify the scenario with the highest agreement among the provided measurement data. The simulation of X-ray contrast media in the water cycle of Berlin showed that medical institutions have to be considered as point sources for congested urban areas due to their high levels of X-ray contrast media emission. The calculations identified hospitals, represented by their capacity (number of hospital beds), as the most relevant point sources, while the inhabitants served as important diffusive sources. Deployed for almost inert substances like contrast media, the model can be used for qualitative statements and, therefore, as a decision-support tool.     

Optimizing the preparation parameters of mesoporous nanocrystalline titania and its photocatalytic activity in water: Physical properties and growth mechanisms

Titania nanomaterial with an anatase structure and 5.6 nm crystallite size and 280.7 m² g⁻¹ specific surface areas had been successfully prepared by sol–gel/hydrothermal route. The effect of pH as a type of autoclave and calcination was studied. Crystallite size and phase composition of the prepared samples were identified. X-ray diffraction analyses showed the presence of anatase with little or no rutile phases. The crystallite size of the prepared TiO₂ with acidic catalyst was both smaller than that prepared with basic catalyst, and was increasing after acidic calcinations by a factor 4–5. Basic calcinations produced a specific increase of 1.5. Rutile ratio and the particle size were increased after calcination at 500 °C. However, TiO₂ powder synthesized using a basic catalyst persisted the anatase phase and a loosely aggregation of particles. Anatase TiO₂ as prepared with acidic catalyst in Teflon lined stainless steel autoclave demonstrated the highest photocatalytic activity for degradation of 2,6-dichlorophenol-indophenol under ultraviolet irradiation with t_½ 0.8 min.     

Quantification of changes in zero valent iron morphology using X-ray computed tomography

Morphological changes within the porous architecture of laboratory scale zero valent iron （ZVI） permeable reactive barriers （PRBs）, after exposure to different groundwater conditions, have been quantified experimentally for different ZVI/sand ratios （10%, 50% and 100%, W/W） with the aim of inferring porosity changes in field barriers. Column studies were conducted to simulate interaction with different water chemistries, a synthetic groundwater, acidic drainage and deionised （DI） water as control. Morphological changes, in terms of pore size and distribution, were measured using X-ray computed tomography （CT）. CT image analysis revealed significant morphological changes in columns treated with different water chemistries. For example, 100% ZVI （W/W） columns had a higher frequency of small pores （0.6 mm） was observed in ZVI grains reacted with typical groundwater, resulting in a porosity of 27%, compared to 32% when exposed to DI water. In comparison, ZVI grains treated with the acidic drainage had higher porosity （44%） and larger average pore size （2.8 mm）. 10% ZVI PRB barrier material had the highest mean porosity （56%） after exposure to any water chemistry whilst 100% ZVI （W/W） columns always had the lowest （34%） with the 50% ZVI （W/W） in between （40%）. These results agree with previously published PRB field data and simultaneously conducted geochemical monitoring and mass balance calculation, indicating that both the geochemical and hydraulic environment of the PRB play an important role in determining barrier lifespan. This study suggests that X-ray CT image analysis is a powerful tool for studying the detailed inter pores between ZVI grains within PRBs.     

Investigation of methods for estimating hand bone dimensions using X-ray hand anthropometric data

This study examined two conversion methods, M1 and M2, to predict finger/phalange bone lengths based on finger/phalange surface lengths. Forty-one Korean college students (25 males and 16 females) were recruited and their finger/phalange surface lengths, bone lengths and grip strengths were measured using a vernier caliper, an X-ray generator and a double-handle force measurement system, respectively. M1 and M2 were defined as formulas able to estimate finger/phalange bone lengths based on one dimension (i.e., surface hand length) and four finger dimensions (surface finger lengths), respectively. As a result of conversion, the estimation errors by M1 presented mean 1.22?mm, which was smaller than those (1.29?mm) by M2. The bone lengths estimated by M1 (mean r?=?0.81) presented higher correlations with the measured bone lengths than those estimated by M2 (0.79). Thus, the M1 method was recommended in the present study, based on conversion simplicity and accuracy.     

A barrier to metal movement: Synchrotron study of iron plaque on roots of wetland plants

正A wetland with attractive plants hosting birds and other wildlife is an esthetically pleasing prospect that is gaining popularity as a way of stabilizing or remediating metalcontaminated soils and sediment(Weber and Gagnon,2014;