红外碳硫测定仪分析等外金属硅中碳

利用红外碳硫测定仪，探索了等外金属硅中碳金属含量的测定方法，对助溶剂的种类，用量及样品的用量等实验条件进行了优化选择，测定快速，结果准确。     

Sources and circulation of water and arsenic in the Giant Mine,Yellowknife, NWT,Canada

Recovery of gold from arsenopyrite-hosted ore in the Giant Mine camp, Yellowknife, NWT, Canada, has left a legacy of arsenic contamination that poses challenges for mine closure planning. Seepage from underground chambers storing some 237,000 tonnes of arsenic trioxide dust, has As concentrations exceeding 4000 ppm. Other potential sources and sinks of As also exist. Sources and movement of water and arsenic are traced using the isotopes of water and sulphate. Mine waters (16 ppm As; As^V/As^III ≈ 150) are a mixture of two principal water sources – locally recharged, low As groundwaters (0.5 ppm As) and Great Slave Lake (GSL; 0.004 ppm As) water, formerly used in ore processing and discharged to the northwest tailings impoundment (NWTP). Mass balance with δ¹⁸O shows that recirculation of NWTP water to the underground through faults and unsealed drillholes contributes about 60% of the mine water. ;[emsp]>Sulphate serves to trace direct infiltration to the As₂O₃ chambers. Sulphate in local, low As groundwaters (0.3–0.6 ppm As; δ³⁴S_SO4  ～ 4 ‰ and δ¹⁸O_SO4  ～ ? 10 ‰) originates from low-temperature aqueous oxidation of sulphide-rich waste rock. The high As waters gain a component of ¹⁸O-enriched sulphate derived from roaster gases (δ¹⁸O_SO4  = + 3.5 ‰), consistent with their arsenic source from the As₂O₃ chambers. High arsenic in NWTP water (～ 8 ppm As; δ¹⁸O_SO4  = ? 2 ‰) derived from mine water, is attenuated to close to 1 ppm during infiltration back to the underground, probably by oxidation and sorption by ferrihydrite.     

柴油中微量硫的发射光谱研究

建立应用电感耦合等离子体发射光谱(ICP-OES)法直接测定柴油中微量硫的分析方法。柴油样品经煤油简单稀释后直接进样分析,高浓度有机溶剂具有较高的饱和蒸气压,会造成等离子体的负载增加从而影响等离子体的稳定性,通过优化仪器的射频功率、载气流量和溶液提升量等工作参数维持了等离子体工作的稳定性,选用轴向观测技术提高了方法的灵敏度。硫的分析谱线处于紫外光区,光室中的氧气会吸收紫外光谱,采用氩气为保护气并延长氩气吹扫光路的时间控制了光室的纯度。采用在等离子体气体中通入一定量的氧气使高浓度有机碳完全燃烧,消除了碳沉积现象。详细地研究了硫的光谱干扰,采用实时背景扣除功能软件进行校正。通过加入内标元素Y校正了基体对硫信号抑制的差异,补偿了部分光谱漂移所带来的误差,有效地改善了测量的精密度。样品的分析结果表明,该方法硫的检出限为0.2 μg·L-1,三水平加标回收率在97.4%～101.8%之间,11次平行测定的相对标准偏差(RSD)在1.6%～2.1%之间。方法的样品前处理过程采用煤油稀释后直接测定,具有操作简单、快速、准确、线性范围广、检出限低和精密度好等特点,可用于柴油中微量硫的快速分析。     

分光光度法测定丙烯中的痕量硫

建立了分光光度法测定丙烯中痕量硫的方法,当样品中硫质量分数在0-1 mg/kg内,样品中硫含量与吸光度呈良好的线性关系,检出限为0.1 mg/kg.该方法适用于丙烯中痕量硫的测定.     

流动注射-阴离子交换预浓集-电感耦合等离子体发射光谱法检测痕量元素——砷、硒、钼、硫、铬

本文研究了阴离子交换树脂D296对待测元素As、Se、Mo、S、Cr的预浓集性能,并与改进的流动注射(FI)(双流路)相结合,建立了一套新型、高效的FI-阴离子交换-ICP-AES分析体系。从而极大地提高了分析的频率和灵敏度,分析速度可达每小时14个样品。As、Se、Mo、S、Cr各元素的检测限分别为13.0 ng/ml、25.2 ng/ml、2.04 ng/ml、6.19 ng/ml、3.64ng/ml。利用此体系检测了标准土壤、头发、牛肝粉等,结果与标准值均很接近。     

氧化锡基甲烷催化燃烧催化剂的硫中毒反应机理

测定了几种活性较高的氧化锡基甲烷燃烧催化剂在200×10－6（φ）SO2存在下的催化活性.结果发现,SnCrO样品具有很好的抗硫性能,而SnCuO及SnCoO样品在SO2存在时的活性大大降低.用XRD、BET、XPS、FT-IR及DTA-TG等技术对反应前后的样品进行了表征,结果表明,硫酸盐的热稳定性对催化剂在SO2处理过程中的变化起决定作用.在实验的温度下（500 ℃）,Co2(SO4)3和CuSO4均能稳定存在,而Cr2(SO4)3会分解.SnCrO样品在SO2存在下反应时只是表面吸附少量硫酸根,因此其催化活性基本保持不变.这是SnCrO样品具有良好抗硫性能的原因.     

过氧乙酸的制备及其在药物合成中的应用

简要介绍了过氧乙酸的主要制备方法,综述了其在药物合成中作为化学氧化剂氧化氮原子,硫原子、烯烃和羰基的应用。参考文献３６篇。     

The local structure of SO2 and SO3 on Ni(1 1 1): A scanned-energy mode photoelectron diffraction study

O 1s and S 2p scanned-energy mode photoelectron diffraction (PhD) data, combined with multiple-scattering simulations, have been used to determine the local adsorption geometry of the SO₂ and SO₃ species on a Ni(1 1 1) surface. For SO₂, the application of reasonable constraints on the molecular conformation used in the simulations leads to the conclusion that the molecule is centred over hollow sites on the surface, with the molecular plane essentially parallel to the surface, and with both S and O atoms offset from atop sites by almost the same distance of 0.65 Å. For SO₃, the results are consistent with earlier work which concluded that surface bonding is through the O atoms, with the S atom higher above the surface and the molecular symmetry axis almost perpendicular to the surface. Based on the O 1s PhD data alone, three local adsorption geometries are comparably acceptable, but only one of these is consistent with the results of an earlier normal-incidence X-ray standing wave (NIXSW) study. This optimised structural model differs somewhat from that originally proposed in the NIXSW investigation.     

Reactivity to sulphur of clean and pre-oxidised Cu(1 1 1) surfaces

The reactivity of clean and pre-oxidised Cu(1 1 1) surfaces exposed to sulphur (H₂S) has been studied at room temperature by Auger electron spectroscopy, low energy electron diffraction and scanning tunneling microscopy. On the clean surface, the sulphur-saturated surface structure is dominated by the or so-called “zigzag” superstructure. It is shown that a single orientation domain is favoured by the slight misorientation (∼2°) of the surface with respect to the (1 1 1) plane. Scanning tunneling microscopy measurements also revealed two minority structures. Pre-oxidation was performed by exposure to 1.5 × 10⁴ L of O₂ at 300 °C. Under exposure to H₂S (1 × 10⁻⁷ mbar) at room temperature, the oxygen is totally substituted by sulphur. Once initiated, sulphur adsorption seems to propagate to cover the whole surface on the O-covered surface faster than on the clean Cu(1 1 1). At saturation by adsorbed sulphur, the surface is completely covered by the superstructure of highest coverage. This enhanced uptake of sulphur is assigned to the surface reconstruction of the copper surface induced by the pre-oxidation, causing a stronger reactivity of the Cu atoms released by the decomposition of the oxide.