Extraction of Metal Ions from Aqueous Solutions Using Imidazolium Based Ionic Liquids

This article represents a step towards how to choose an ionic liquid as the solvent to improve metal ion (Ag⁺ and Pb²⁺) extraction. The liquid-liquid solvent extraction is proposed with the following imidazolium ionic liquids (ILs): 1-ethyl-3-ethylimidazolium, or 1-butyl-3-ethylimidazolium, or 1-hexyl-3-ethylimidazolium bis{(trifluoromethyl)sylfonyl}imide [EEIM][NTf₂], or [BEIM][NTf₂], or [HEIM][NTf₂], or 1-butyl-3-ethylimidazolium hexafluorophosphate [BEIM][PF₆], or 1-hexyl-3-ethylimidazolium hexafluorophosphate [HEIM][PF₆] and the popular 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF₆] for comparison. The effect of anion type (NTf₂⁻ versus PF₆⁻) and the effect of structural components of an ionic liquid including alkyl chain length at the cation and the ethyl substituent instead methyl at the cation, on the extraction and re-extraction processes by using dithizone as a metal chelator, were studied at 296 K. Dithizone was employed to form neutral metal-dithizone complexes with heavy metal ions to extract them from aqueous solution into the ILs. Electronic Supplementary Material  The online version of this article () contains supplementary material, which is available to authorized users. Presented at the 236th ACS National Meeting, August 17–21, Philadelphia, USA.     

Speciation analysis of mercury in water samples by cold vapor atomic absorption spectrometry after preconcentration with dithizone immobilized on microcrystalline naphthalene

Trace amounts of inorganic mercury (Hg²⁺) and methylmercury cations (MeHg²⁺) were adsorbed quantitatively from acidic aqueous solution onto a column packed with immobilized dithizone on microcrystalline naphthalene. The trapped mercury was eluted with 10 ml of 7 mol L^–1 hydrochloric acid solution. The Hg²⁺ was then directly reduced with tin (II) chloride, and volatilized mercury was determined by cold vapor atomic absorption spectrometry (CVAAS). Total mercury (Hgt) was determined after decomposition of MeHg⁺ into Hg²⁺. Hg²⁺ and MeHg⁺ cations were completely recovered from the water with a preconcentration factor of 200. The relative standard deviation obtained for eight replicate determinations at a concentration of 0.3 g L^–1 was 1.8%. The procedure was applied to analysis of water samples, and the accuracy was assessed via recovery experiment.     

Exploiting the bead injection concept for sequential determination of copper and mercury ions in river-water samples

A procedure involving bead-injection concept and sequential determination of copper and mercury ions in river-water samples is proposed. The method is based on the solid-phase extraction of both metal ions on the same beads surface (Chelex 100 resin) and in their subsequent reaction with the colorimetric reagents (APDC and Dithizone for copper and mercury ions, respectively). For this task, a resin mini-column is established in the optical path by the selection, introduction and trapping of a defined volume of the Chelex-100 resin beads suspension in the flow system. The passage of the sample solution through the resin mini-column promotes the sorption of Cu(II) ions and, making the APDC colorimetric reagent flows through the beads, the formation of the coloured complex on the solid phase surface occurs. The absorbance of the formed APDC-Cu complex is then monitored at 436 nm and the spent beads are discarded. Packing another resin mini-column in the flow cell and repeating the concentration step it is possible to carried out the mercury determination by using Dithizone as reagent. The absorbance of the Dithizone-Hg complex is monitored at 500 nm. After each measurement, the spent beads are wasted and a new portion of fresh one is trapped in the system, letting it ready for the next measurement. The bead injection system is versatile and can be used to concentrate different sample volumes, which permits the determination of a wide range of copper and mercury ions concentrations. When the sample-selected volumes are 100 and 1000 μl the analytical ranges were 5.0 up to 500.0 μg l⁻¹ and 2.5 up to 30.0 μg l⁻¹ for Cu(II) and Hg(II) ions, respectively. Under these conditions, the detection limit was estimated as 0.63 and 0.25 μg l⁻¹ for copper and mercury ions determination. The system consumes 2 mg of Chelex 100 resin beads, 0.20 mg of APDC or 1.25 mg of Dithizone per determination and the traditional organic solvent extraction methodology, normally used in connection with APDC and Dithizone reagents, is not used here which permits to classify the present method as green.     

浊点萃取-火焰原子吸收光谱法测定淡水鱼中痕量铅

采用以双硫腙为络合剂、Triton X-100为表面活性剂的新型浊点萃取体系富集淡水鱼中的痕量铅,并用火焰原子吸收光谱法对其进行测定。探讨了溶液pH、表面活性剂浓度、络合剂用量、平衡温度、平衡时间等对浊点萃取及测定灵敏度的影响,优化了实验条件。在最佳条件下测得铅的检出限为0.090μg/L,校准曲线相关系数为0.9999。该方法已用于淡水鱼中痕量铅的测定。     

Carrier-mediated blends of Chitosan with polyvinyl chloride for different applications

The current work aims at blending of PVC with Chitosan through simultaneous casting of their separate solutions in different proportions of PVC and Chitosan in suitable solvents. After dissolution, both solutions were added to each other while stirring at room temperature. The obtained mixture was left at room temperature to form the blend after evaporation of the solvent. Similar blends have been prepared similarly in presence of the organic ligand, dithizone, as a carrier-mediating material for different metal ions. PVC/Chitosan blends were characterized by thermal (TGA) and FT-IR Spectroscopic analyses as well as scanning electron microscopy (SEM). The obtained blends were found to have reasonable extent of compatibility between their components. Such compatibility depends mainly on the way with which the components have been blended with each other. The polymer-supported dithizone was investigated toward its ability to be used for removal of some metal ions from their aqueous solutions. Concentration of metal ions was determined by ICP-AES analysis.     

冰硼散中朱砂的含量测定

采用双硫腙比色法测定冰硼数中朱砂的含量．结果表明。该法分析结果准确可靠．RSD为1．17％，回收率102．7%．所需仪器普通。操作简单，快速。可供一般药厂生产中控制朱砂含量时参考．     

催化光度法测定痕量铁的研究

本文研究了在ｐＨ４．５的ＨＡｃ－ＮａＡｃ介质中，有非离子表面活性剂ＴｒｉｔｏｎＸ－１００存在下，痕量铁催化水中溶解氧氧化双硫腙褪色的指示反应，建立了胶束增溶催化动力学光度法测定痕量铁的新方法。方法的线性范围为０－１．５μｇ／２５ｍＬ，检出限为１．６×１０￣（－１０）ｇ／ｍＬ。用于人发中痕量铁的测定，结果满意。     

双硫腙分光光度法测定空气中汞的改进

对双硫腙显色分光光度法测定空气中的痕量汞的条件进行了改进,探讨了测定波长、掩蔽剂EDTA的用量等实验条件。校准曲线方程为A=0.0689C-0.0009,r=0.9991,平均回收率为99.6%,相对标准偏差为3.1%。     

双硫腙光极法测定废水中的痕量汞离子

本文用双硫腙为探针制备了PVC膜离子选择性光极,在优化膜组成和考察对常见金属离子响应的基础上,提出了一种测定痕量汞的光极方法。结果表明:光极膜组成为双硫腙∶PVC∶DOP∶KTpClPB(相对于双硫腙的mol%)=4∶60∶120∶50%时,对汞离子的响应最佳;在pH4.5的缓冲体系中,该光极对5×10-8～7×10-7mol/L的Hg2+有线性响应,检出限达4×10-8mol/L,只有Ag+、Pb2+有较小干扰,可用于水体中痕量汞的快速检出。     

微波消解双硫腙水相增溶分光光度法测定尿中铅

研究了在Tween－20增溶下，双硫腙水相直接光度法测定的系列条件，同时，用微波消解样品，不经分离富集，直接应用于尿中铅的测定，结果满意。最大吸收波长λ＝480nm，ε480＝1．24×105·L·mol－1·cm－1