Anion exchange separation of chromium and molybdenum from iron,vanadium, uranium and other elements in malonic acid solution

Summary Anion-exchange behaviour of chromium (III) and molybdenum (VI) was studied in malonate media. They form anionic complexes with malonic acid at pH 5.6. Various eluants, such as mineral acids and their salts were tested and a selectivity scale evolved. Cr and Mo were separated from Tl(I), alkali and alkaline earth elements by selective sorption and from Co(II), Ni(II), Mn(II), Zn(II) and Cd(II) by selective washing with water. They were separated from many other elements by selective elution. The sequential separation of Fe(III) V(IV), Cr(III), Mo(VI) and U(VI) was significant.     

Spectrophotometric determination of scandium with arsenazo

Arsenazo is used for the spectrophotometric determination of scandium in the range 10 to 50 μg. The absorbance is measured at 570 mμ and pH 6.1. A method is proposed for the successive determination of scandium and thorium. Scandium is separated from magnesium, calcium, rare earths, zirconium, fluoride, phosphate, and some other metals by extraction with TTA in xylene. Copper, aluminum, and iron(III) are removed by 8-quinolinol-chloroform extraction. Uranium(VI) is removed by anion exchange using hydrochloric acid. Thorium is separated from scandium by anion exchange using nitric acid.     

Analytical applications of a liquid anion-exchanger for the separation of uranium(IV) in malonate solution

Uranium was quantitatively extracted with 4% Amberlite LA-1 in xylene at pH 2.5-4.0 from 0.001 M malonic acid. It was stripped from the organic phase with 0.01 M sodium hydroxide and determined spectrophotometrically at 530 nm as its complex with 4-(2-pyridylazo) resorcinol. Of various liquid anion-exchangers tested, Amberlite LA-1 was found to be best. Uranium was separated from alkali and alkaline earth metal ions, thallium(I), iron(II), silver, arsenic(III) and tin(IV) by selective extraction, and from zinc, cadmium, nickel, copper(II), cobalt(II), chromium(III), aluminium, iron(III), lead, bismuth, antimony(III) and yttrium by selective stripping. The separation from scandium, zirconium, thorium and vanadium(V) was done by exploiting differences in the stability of chloro-complexes.     

Selective separation and extraction of copper(II), iron(II,III), and Cerium(III,IV) ions from aqueous solutions by electroflotation method

Possibility of the electroflotation separation and extraction of cerium(II, IV), copper(II), and iron(II, III) from aqueous solutions is demonstrated. The optimal pH value and the concentration ratio of ions of the metals being separated, at which their electroflotation separation and extraction from aqueous solutions is the most efficient, was determined. It was shown that the electroflotation method is promising for selective separation and extraction of metal ions with various hydrate-formation pH values from aqueous solutions.     

Quantitative separation of lanthanides and scandium from barium,strontium and other elements by cation-exchange chromatography in nitric acid

The lanthanides plus yttrium and scandium are separated from Ba, Sr, Ca, Mg, Pb(II), Bi(III), Zn, Mn(II) and U(VI) by eluting these elements with 2.0 M nitric acid from a column of AG50W-X8 cation exchange resin (200-400 mesh). The lanthanides are retained and can then be eluted with 4 M nitric or hydrochloric acid. Separations are quantitative and applicable to microgram and millimolar amounts of the lanthanides and the other elements. Elements such as Cu(II), Co(II), Ni(II), Cd. Hg(II), T1(I). Ag, Be, Ti(IV) and the alkali metals should accompany barium quantitatively according to their known distribution coefficients. Relevant elution curves and results of analysis of synthetic mixtures are presented.     

Determination of zirconium,thorium and scandium with 2,5-dihydroxy-1,4-benzoquinone

Zirconium is quantitatively precipitated by 2,5-dihydroxy-1,4-benzoquinone and is separated from scandium in 1 N hydrochloric acid solution. Thorium is separated at pH 0.5 from uranium(VI), cerium(IV), lanthanum, yttrium and scandium. Scandium is quantitatively precipitated by this reagent in the pH range 1.4–2.0 and at pH 1.5 equivalent amounts of lanthanum do not interfere; small amounts of yttrium cause interference.     

Simultaneous determination of trace amounts of cadmium, nickel and cobalt in water samples by adsorptive voltammetry using ammonium 2-amino-cyclopentene dithiocarboxylate as a chelating agent

This paper reports the use of an adsorptive voltammetric technique for the simultaneous detection of Cd(II), Ni(II) and Co(II) using ammonium 2-amino-cyclopente dithiocarboxylate as a selective complexing agent. Scans containing three resolved peaks corresponding to these metals were obtained in synthetic and real samples. The reduction current peaks of the metals that were distinctly separated by 200 mV or more, allowing their determination over a wide range of concentrations. These metals can be quantified at concentrations above 1.33x10(-8) mol dm(-3) Cd(II), 8.51x10(-9) mol dm(-3) Ni(II) and 3.39x10(-10) mol dm(-3) Co(II). The influence of pH, ligand concentration, scan rate, accumulations time and applied potential was investigated. The R.S.D. at a concentration level of 1.78x10(-7) mol dm(-3) of Cd(II), 3.40x10(-7) mol dm(-3) and Ni(II) and 1.7x10(-9) mol dm(-3) of Co(II) was 2.5% for Cd(II), 2.7% for Ni(II) and 3.3% for Co(II). The method was applied to various water samples.     

Cation exchange studies of vanadium(V) on Dowex 50W-X8. Separation from mixtures

Summary The cation exchange behaviour of milligram amounts of vanadium on Dowex 50W-X8 has been studied using different eluants. Quantitative elution can be achieved by 200 ml of 0.5N hydrochloric acid, 1–2N sulphuric acid, 2–3N phosphoric acid or 0.5–1N ammonium chloride solution. The relative efficiency of eluants is discussed in terms of their elution constants and bed distribution coefficients. Vanadium has been separated from copper(II), iron(III), cobalt(II), nickel, zinc, zirconium (IV), aluminium, cerium(IV), uranium(VI), thorium(IV), manganese(II), titanium(IV), and from phosphate.

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Zusammenfassung Das Verhalten von Milligramm-Mengen Vanadium am Kationenaustauscher Dowex 50W-X8 wurde mit verschiedenen Eluierungsmitteln untersucht. Mit 200ml 0,5 n Salzsäure, 1–2 n Schwefelsäure, 2–3 n Phosphorsäure oder 0,5–1 n Ammoniumchloridlösung konnte das Vanadium quantitativ eluiert werden. Die Wirksamkeit dieser Eluierungslösungen wurde an Hand der Elutionskonstanten und der Verteilungskoeffizienten erörtert. Von folgenden Ionen konnte das Vanadium getrennt werden: Kupfer(II), Eisen(III), Kobalt(II), Nickel, Zink, Zirkonium(IV), Aluminium, Cer(IV), Uran(VI), Thorium(IV), Mangan(II), Titan(IV) und Phosphat.

     

反相离子对高效液相色谱法分离测定钪、锡和铝

 以 1,2 二苯乙烯 4,4′ 双 (1 偶氮 ) 3,4 二羟基苯 2 ,2′ 二磺酸铵 (芪唑 )为柱前衍生试剂 ,采用反相离子对高效液相色谱法分离和测定钪、锡和铝。在C18柱上 ,用含 2 0mmol/LHAc NaAc缓冲溶液 (pH 6 0 )和 10mmol/L十二烷基磺酸钠的甲醇水溶液作流动相 ,检测波长 5 0 0nm ,同时分离测定了钪、锡和铝的络合物。钪、锡和铝的检出限分别为 0 9μg/L ,1 0 μg/L和 1 2 μg/L ,此方法用于矿石样品分析获得满意结果。     

Determination of trace cadmium in environmental water samples using ion-interaction reversed-phase liquid chromatography with fluorescence detection

An ion-interaction reversed-phase liquid chromatographic method has been developed for the determination of cadmium at low microg/l concentrations in environmental water samples. Cadmium and other matrix metals were separated through on-column complexation with 8-hydroxyquinoline sulphonate, using an octadecylsilica column and a mobile phase containing 15% acetonitrile, 10-13 mM tetrabutylammonium hydroxide, 5 mM 8-hydroxyquinoline 5-sulphonic acid and 10 mM acetic acid-acetate buffer (pH 4.8-5.4). Under the above conditions Cd(II) could be easily resolved from excess concentrations of matrix metals and could be detected at concentrations as low as 2 microg/l using fluorescence detection at 500 nm (based upon a 100-microl injection). The method showed a slightly curved detector response over the range of interest [up to 1 mg/l Cd(II)] and was successfully applied to the determination of trace Cd(II) in water samples containing large excesses of Mg(II) and Zn(II) and other matrix metals.     

Aktivierungsanalytische Bestimmung von Verunreinigungen in Aluminium. III

Zusammenfassung Die aktivierungsanaiytische Bestimmung der Elemente Eisen, Kobalt, Zink und Scandium in Aluminium wird beschrieben. Diese Metalle werden mit Hilfe eines Lösungsmittelextraktionsganges voneinander getrennt, und zwar in folgender Reihenfolge: Eisen in 8-n HCl mit Diisopropyläther, Kobalt bei pH 3 bis 4 mit 2-Nitroso-1-Naphthol und Chloroform, Zink in 2-n HCl mit TBP (100%) und Scandium in 8-n HCl mit TBP (100%).

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Summary The activation analytical determination of the elements iron, cobalt, zinc, and scandium in aluminium is described. These metals are separated from each other by a solvent extraction procedure and in the following succession: iron in 8N HCL with diisopropyl ether, cobalt at p_H 3–4 with 2-nitroso-1-naphthol and chloroform, zinc in 2N HCl with TBP (100%) and scandium in 8N HCl with TBP (100%).

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Résumé On décrit le dosage par activation des éléments fer, cobalt, zinc et scandium dans l'aluminium. On sépare ces métaux les uns des autres suivant un processus d'extraction par solvant et dans l'ordre suivant: le fer dans HCl 8 N par l'éther diisopropylique, le cobalt à p_H 3–4 par le-nitroso -naphtol et chloroforme, le zinc dans HCl 2 N par le phosphate de tributyle (100%) et le scandium dans HCl 8 N par le phosphate de tributyle (100%).

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I. und II. Mitteilung: siehe 6,7.     

Simultaneous determination of trace amounts of nickel, cobalt, and zinc in the wastewater of a galvanic workshop by using adsorptive cathodic stripping voltammetry

Electroplating of Ni, Co, and Zn is widely used in the industry, because coating of tools with these materials can improve mechanical and chemical properties such as hardness, toughness, and corrosion resistively. Ni, Co, and Zn are among toxic metals of significance for environmental surveillance. Therefore, determination of these elements in wastewater is very important. This paper reports the use of an adsorptive cathodic stripping voltammetric technique for the simultaneous determination of Ni(II), Co(II), and Zn(II) with dimethylglyoxime (DMG) as a chelating agent. Voltammograms of Ni(II), Co(II), and Zn(II) initially contained three peaks corresponding to these metals. However, the peaks overlapped. Therefore, the effect of organic solvents was studied, and the results showed that the use of a suitable ratio of ethanol-water (1:5) solvent and pH provided peaks that were distinctly separated. The metals can be quantified at concentrations above 0.03 (Ni), 0.02 (Co), and 0.1 μg/mL (Zn). The RSD (%) at concentration levels of 0.10 μg/mL Ni(II), 0.10 μg/mL Co(II), and 0.30 μg/mL Zn(II) is 2.3, 2.0, and 3.3%, respectively. The influence of pH, DMG concentration, scan rate, accumulations time, and potential was investigated. The method was satisfactorily used for determination of the metals under study in water and wastewater. The text was submitted by the authors in English.     

Separation of uranium(vi) by liquid-solid extraction with tri-n-octylphosphine oxide diluted with naphthalene

Liquid-liquid distribution with tri-n-octylphosphine oxide (TOPO)and molten naphthalene has been investigated for the extraction of 20 metals from nitric acid and hydrochloric acid solutions. Uranium is quantitatively extracted from 1 M nitric acid or hydrochloric acid by using 100 mg of TOPO and 200 mg of naphthalene and shaking for 5 min at 80°C, and separated from transition metals, alkaline earth metals and rare earth metals (except scandium). Addition of naphthalene increases the extraction efficiency.     

Cation exchange behaviour of strontium on dowex 50W-X8: Separation from mixtures

The cation exchange chromatography of strontium on Dowex 50W-X8 is described. Nitric acid hydrochloric acid. ammonium chloride, sodium nitrate, ammonium acetate and citric acid were examined as eluants. Strontium can be separated frum important fission products such as caesium zinc, cadmium, silver and zirconium and also from uranium(VI), thorium, bismuth, iron(IIl) copper(Il) and mercury(II).     

Cation Exchange Separation of Thallium (I) From Other Elements In Mixed Solvents

Abstract

The cation exchange chromatographic behaviour of thallium (I) on Dowex 50W-X8 was carried out in mixed solvents. Nitric, sulphuric, perchloric acid and their salts, as well as in mixtures of 2 M nitric acid with methanol, ethanol, acetone, dioxane and titrahydrofuran, were studied as the eluants. In comparison with other elements, since thallium was weakly sorbed, it was first eluted, while strongly bound elements like manganese, magnesium, cobalt, indium, gallium, zinc, iron, scandium, yttrium, aluminium, calcium, strontium, and barium were subsequently eluted. The best separations were possible from nitric acid in the presence of non-aqueous solvents such as methanol and ethanol.     

Polymer supported 5,10,15,20-tetrakis(phenoxy acetic acid)porphyrin derivative for separation and preconcentration of d- and f-electron metals

5,10,15,20-tetrakis(phenoxy acetic acid) porphyrin (PAAP) was covalently linked to Merrifield chloromethylated resin. Characterization of PAAP and the modified polymeric matrix were performed by ¹H NMR, FTIR and elemental analysis. The sorbent was used for the separation and enrichment of the d-electron metals (Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)) at pH 6–8 and of the f-electron metals U(VI) and Th(IV) at pH 4–5. The metals ions were preconcentrated with a concentration factor range of 115–215 and then determined by flame atomic absorption spectrometry or visible spectrophotometry using Arsenazo(III). The retained metals were eluted with 2.0 mol L⁻¹ HNO₃ in the case of the d-electron metals and 0.1/0.25 mol L⁻¹ HCl in the case of the f-electron metals. The procedure was validated by analyzing the NIST standard reference material 2709 (San Joaquin Soil). Correspondence: Melek Merdivan, Chemistry Department, Faculty of Arts and Sciences, Dokuz Eylul University, 35160 Buca, Izmir, Turkey     

Propiconazole and Penconazole as Effective Extractants for Selective recovery and concentration of platinum(IV) and palladium(II) from hydrochloric acid solutions formed in leaching of spent aluminoplatinum and aluminopalladium catalysts

Selective recovery and concentration of platinum(IV) and palladium(II) from hydrochloric acid solutions of varied composition was studied using commercial reagents propiconazole and penconazole as extractants. The ranges of hydrochloric acid concentrations for effective extraction and highly selective separation of platinum metals from Al(III) and Ni(II) with propiconazole (toluene with 15 vol % n-decanol as deluent) and penconazole (chloroform) were determined. The conditions for 10-fold selective concentration of platinum metals with recovery of more than 99.9% of metal ions into the organic phase were found. The conditions for quantitative (>99%) stripping of platinum(IV) with a hydrochloric acid solution of thiourea and palladium(II) with ammonia solution were determined. The results obtained can be used for optimizing the modes of selective recovery of platinum(IV) and palladium(II) from hydrochloric acid solutions formed in leaching of alumina-supported platinum-rhenium, platinum-nickel, and palladium catalysts.     

Determination of cadmium, zinc, nickel and cobalt in tobacco by reversed-phase high-performance liquid chromatography with 2-(8-quinolylazo)-4,5-diphenylimidazole as a chelating reagent.

A sensitive and selective method has been developed for the simultaneous determination of cadmium, zinc, nickel and cobalt. The method is based on the chelation of metal ions with 2-(8-quinolylazo)-4,5-diphenylimidazole (QAI) and the subsequent reversed-phase (RP) high-performance liquid chromatographic separation and spectrophotometric detection of the metal chelates. The chelates were separated on an RP column with acetonitrile-water containing ethylenediamine tetraacetic acid and sodium acetate (pH 7.5). Though Zn(II) and Cd(II) chelates with azo compounds were generally labile in the RP column, these chelates with QAI were successfully detected. When analyses were carried out at 575 nm and at 0.001 absorbance unit full scale, the peak height calibration curves were linear up to 2.0 ng for Cd(II), 2.4 ng for Zn(II), 0.14 ng for Ni(II) and 0.72 ng for Co(II) in 100-microL injections, respectively; the detection limits (3sigma, three times of the standard deviation for the blank signal) for Cd(II), Zn(II), Ni(II) and Co(II) were 4.8, 24, 2.4 and 7.2 pg in 100 microL of injected solution, respectively. The proposed method was successfully applied to the analysis of tobacco without any preliminary concentration or separation.     

A radiochemical method of separation of carrier-free vanadium from scandium and bulk amount of titanium

A method for the separation of carrier-free vanadium from scandium and bulk amount of titanium has been developed. Vanadium has been produced through the reaction^natTi(d,n)^48,49V with 8 MeV deuterons from the Variable Energy Cyclotron, Calcutta. The separation is performed with Dowex 1×8, 50–100 mesh fluoride from anion exchange resin which retains all the scandium and titanium with 4.5M hydrofluoric acid as eluent, while vanadium(V) is easily eluted. The chemical yield of vanadium was >85%.     

Extractive separation of Cu<Superscript>2+</Superscript>–Co<Superscript>2+</Superscript> and Ni<Superscript>2+</Superscript>–Co<Superscript>2+</Superscript> mixtures using <Emphasis Type="Italic">N</Emphasis>-salicylideneaniline

A study on the extraction of copper(II), cobalt(II), and nickel(II) from solutions containing ions of both metals with N-salicylideneaniline(SAN) in chloroform has been realized. Distribution of the metal ions in wide range of pH has been studied. Extraction of copper(II) was always favored over that of cobalt(II). Extraction of copper(II) from binary metal solution is selective and it can be quantitatively separated from cobalt(II). The equilibrium constant of the extraction of cobalt and nickel from an aqueous solution containing both metals using SAN were evaluated. The separation factors for cobalt and nickel were expressed as a function of the distribution of nickel and cobalt. From these results, salicylideneaniline is an adequate extractant for extractive separation of such mixtures.