在聚乙烯醇-124存在下钌-二氯化锡-乙基紫离子缔合体系测定钌的研究

本文对钌(Ⅲ)SnCl_2-EV高灵敏显色体系测定钌进行了研究。摩尔吸光系数ε_(640nm)高达1.5×10~5L.mol~(-1)·cm~(-1),钌含量在0.2～1.4和1.4～2.2μg/25ml范围内符合比尔定律.对外来离子的干扰进行了研究,并对纯金属镍中痕量钌的含量进行了测定。     

离子型共价有机框架材料的制备及对染料吸附性能的研究

茜素红(Alizarin Red,AR)作为蒽醌类染料中的重要组成,由于其具有优异的特性,在染料和酸碱指示剂等方面被广泛使用。但是AR具有毒性高、结构复杂以及化学需氧量(COD)值大等原因,使其成为了主要污染物之一,去除水体中的茜素红染料污染物已经成为了目前亟待解决的问题。共价有机框架材料作为一种新型的多孔有机材料,由于其具有比表面积大,孔径均一和可设计的独特优势,已经广泛应用吸附和分离等方面。因此,以三醛基间苯三酚和溴化乙锭为构筑单元,通过水热的方法合成一种二维离子型共价有机框架材料(TpEB-COF)。对制备的TpEB-COF进行相关表征,包括X射线衍射仪(XRD),扫描电镜(SEM)和能量色散谱仪(EDS)等。然后将制备的TpEB-COF作为固体吸附剂,将其应用对水中AR的吸附,研究了不同吸附时间和不同pH值对吸附过程的影响。实验结果证明制备的离子型共价有机框架材料具有良好的晶型结构。同时,对实验数据分析表明,离子型共价有机框架材料对于茜素红的吸附符合准二级动力学方程和Langmuir吸附模型,吸附效率为82.8%,最大吸附量为828 mg g-1。本研究不仅为共价有机框架材料的设计和合成奠定坚实的基础,而且拓展了离子型共价有机框架材料的应用范围,促进共价有机框架材料的发展。     

Separation of Mercury with an Ammonium Sulfate‐Ammonium Thiocyanate‐Ethyl Violet Flotation System

The separation behavior of mercury by a flotation system consisting of ammonium sulfate, ammonium thiocyanate and ethyl violet, and the conditions for the separation of Hg(II) with other common metal ions have been studied. The studies show that in aqueous solutions, Hg(II) combines with NH₄SCN and ethyl violet(EV) into dissoluble ternary ion‐association complex [Hg(SCN)4^2?]?(EV)₂. In the presence of ammonium sulfate, the precipitate is floats well on the surface of the water phase and separates from water thoroughly. It shows that Hg(II) can be separated completely from Cd(II), Fe(II), Co(II), Ni(II), Mn(II) and Al(III) by flotation at pH1.0. The flotation mechanism of Hg(II) is described in this paper.     

Real-time monitoring of Yb vapor density using an extended cavity violet diode laser

Based on laser absorption spectroscopy (LAS), we developed a vapor density monitor for controlling the vaporization rate of Yb using a tunable diode laser. The laser source consisted of an extended cavity violet diode laser which has an emission wavelength of 398.8 nm coincident with the Yb absorption transition line, 6s(2) 1S(0)-6s6p 1P(1). The light emitted from the diode laser was transmitted across an atomic vapor column generated by heating the Yb metal, while the laser frequency was scanned across the atomic transition line. By comparing the amount of incident light to the amount of light transmitted after the light passed through the vapor column, the vapor density was determined using the Beer's law. From the experimental results, we demonstrated that the diode-laser-based LAS operated successfully for the real-time monitoring of the Yb vapor density.     

Sorption of some azo-dyes on wool fiber from aqueous solutions

Sorption of some azo-dyes (acid violet 17, acid blue 90, acid red 1 and direct red 80) on locally available wool fiber from aqueous solution has been investigated as a function of shaking time, pH and dyes concentration as a function of temperature. Sorption isotherms for dyes on wool fiber were obtained. It was found that the increasing temperature induces positive effect on the sorption process. Isosteric heat of adsorption (q_st) have also been calculated at different surface coverage indicating that wool fiber used possessed heterogeneous surface with site of different activity. The results also indicate that initial sorption whether chemical or physical means, occurs first on the most active sites and then, as the concentration of dyes is increased, on sites of lesser activity.     

Spectrophotometric procedures for the determination of roxithromycin in pharmaceutical formulations

Four simple and sensitive visible spectrophotometric procedures for the assay of roxithromycin (RXT) have been developed. Procedures A and B are based on the formation of ion-pairs of roxithromycin with the dyes supracen violet 3B and tropaeolin 000, which are extracted into chloroform and have absorption maxima at 590 nm (SV 3B) and 490 nm (TP 000). Procedures C and D are based on condensation between the hydrolysis product of RXT in the presence of 3.6M hydrochloric acid in acetic acid medium and vanillin orp-dimethylaminobenzaldehyde (PDAB) to form coloured products with _max at 500 nm. Regression analysis of the Beer's plot showed good correlation in the concentration ranges 5–60 (A), 5–40 (B) and 5–50 (C & D) g/ml. No interference was observed from excipients and the validity of the procedures was tested by analysing pharmaceutical formulations. Recoveries were 99.0–102.0%. The concentration measurements are reproducible within a relative standard deviation of 1.0%.     

硫酸铵存在下碘化物—结晶紫—丙醇体系萃取分离镉

研究了硫酸铵存在下，碘化物－结晶紫－丙醇体系萃取镉的行为以及丙醇水溶液的分相条件，试验表明，丙醇作为萃取溶剂，能萃取中性离子缔合物，调节溶液ｐＨ＝１．０或ｐＨ＝４．０，该体系使能Ｃｄ＾２＋，从常见过渡元素Ｆｅ＾３＋，Ｃｏ＾２＋，Ｎｉ＾２＋，Ｍｎ＾２＋，Ｚｎ＾２＋，Ｃｒ＾３＋的混合液中分离出来。     

Determination of tungsten with pyrocatechol violet by first-derivative solid-phase spectrophotometry

Derivative spectrophotometry was applied to solid-phase spectrophotometry in order to enhance its sensitivity and remove the large background caused by the absorbance of the resin layer. Determination of micro-amounts of tungsten with pyrocatechol violet to form a 21 green complex in acid medium which is fixed on a dextran-type anion-exchange resin (Sephadex QAEA-25) is described as an example for the application of this technique. The absorbance of the resin packed in a 1-mm spectrophotometric cell, was measured directly. The characteristic peak amplitude of the signal at 674 nm in the first-derivative spectrum is useful for quantitative determination of tungsten (3–16 g 1^–1; RSD 5.8%) in natural and industrial water samples.     

催化光度法测定微量草酸盐

草酸盐对Cr(Ⅲ)-茜素红S(ARS)显色体系的慢反应在微酸性条件下具有显著的催化作用.据此提出了一种测定微量草酸盐的动力学新方法,确定了最佳测定条件.方法操作简单,在C_2O~(2-)_4 0～140.8mg·L~(-1)范围内,草酸盐含量与催化-非催化体系的吸光度之差呈良好的线性关系.方法的检出限为3.86mg·L~(-1),除CN~(-)、CO~(2-)_3外,其它阴离子不干扰测定.