Separation of metal ions on tin(iv) tungstate and selenite papers

Papers impregnated with the inorganic ion-exchangers tin(IV) tungstate and selenite have been shown to be useful for ion-exchange chromatography of several metal ion mixtures, and suitable solvent systems have been developed and evaluated.     

Electrochromatographic separation of metal ions on tin(IV) phosphate papers

Electrochromatographic separations on tin(IV) phosphate papers in 12 background electrolytes are described. Migration distances for 48 ions are given. Many binary as well as ternary separations are readily achieved, e.g. Fe-Cr, Sr-Ba, Pt-Ru- Cu and Au-Pd-Cu.     

Chromatographic behaviour of 47 metal ions on titanium(IV) arsenate papers

Titanium arsenate papers with As/Ti ratios 0.2-2.2 have been prepared and 47 metal ions chromatographed on these papers in 10(-5)-4M nitric acid. The effect of pH and of the Ti/As ratio on the R(f) values has been studied. A new quantity R(i) (R(i) = R(f) on untreated papers minus R(f) on treated papers) has been defined. The effect of the concentration of the loading reagents on the Ti/As ratio of the ion-exchanger precipitated on the papers has been determined Contrary to Alberti, it is shown that Lederer's equation is obeyed by titanium arsenate papers in the sodium form if the activity of Na(+) ions is considered instead of their concentration. It has also been demonstrated that the selectivity sequence for cations on titanium arsenate papers is not the same as that on titanium arsenate columns.     

Chromatographic behaviour of metal ions on tin(IV) and titanium(IV) antimonate papers

Summary The chromatographic behaviour of 49 metal ions has been studied on papers impregnated with Sn(IV) and Ti(IV) antimonates in aqueous HNO₃ and mixed solvent systems containing dimethyl sulphoxide. Numerous separations have been achieved and the Alberti equation, for Sn(IV) and Ti(IV) antimonate papers, in the modified form: –nloga K⁺=R_M + constant (a K⁺=activity of K⁺), has been verified. The effect of the concentration of impregnating reagents on these papers has been determined and compared with other papers. The effect of pH on R_f, R_i, log R_f and R_M values of metal ions has also been examined in aqueous systems.     

Cation chromatography on stannic tungstate papers: Quantitative separation of vanadium from iron,titanium, zirconium and thorium

Summary A systematic study of the chromatography of metal ions on stannic tungstate papers has been performed using acetone-HNO₃–H₂O systems. The effect of mole fractions of acetone, HNO₃ and H₂O on the R_f values of the metal ions has been discussed in detail and a relationship between R_f and mole fraction (X) of the solvent has been obtained as R_f=mX+C. The usefulness of the study has been demonstrated by the specific extraction of titanium and thorium in HNO₃H₂O (12) and HNO₃:acetone:H₂O (161) systems. In addition, some binary and ternary separations of metal ions have also been achieved on these papers.     

Synthesis and characterization of zirconium(IV) 4-amino, 3-hydroxy naphthalene sulfonate ion exchanger: Quantitative separation of mercury from numerous metal ions

Zirconium (IV) 4-amino, 3-hydroxy naphthalene sulfonate ion-exchanger has been synthesized by mixing equimolar solutions of zirconium oxychloride and ammonium hydroxide in molar ratio 1:1.66 to get a gelatinous material. To this were added varying amounts of 4-amino, 3-hydroxynaphthalene sulphonic acid (ANSA) with constant stiring in order to ensure a complete adsorption of organic molecules to the surface of the gel. The ion exchange material shows a dual character possessing both cation and anion exchange capacities. The former is attributed to the dissociation of strong sulphonic groups from ANSA and acidic sites of hydrous oxide gel, the later one is due to the formation of a positive charge on the nitrogen atom ; in addition, the material may have a sorption capacity. A preliminary investigation to characterize the material has been carried out which includes IR, TGA, DTA and X-ray diffraction. On the basis of distribution coefficients the separation of Hg⁺² from Zn²⁺, Al²⁺, Ni²⁺, Ce⁴⁺, Mg²⁺, Pb²⁺, Mn²⁺, Cu²⁺, has been achieved. The decreasing sequence of Kd values for different anionic species are found to be PO₄³⁻ > Fe (CN)₆³⁻ > MnO₄⁻ > VO₃⁻ > AsO₄³⁻ > C₂O₄²⁻ and for halides Cl⁻ > Br⁻ > I⁻.     

Adsorption behavior of noble metal ions (Au, Ag, Pd) on nanometer-size titanium dioxide with ICP-AES.

The adsorption behavior of gold (Au), silver (Ag) and palladium (Pd) on nanometer-size titanium dioxide (NSTD) at low concentrations was studied using inductively coupled plasma atomic emission spectrometry (ICP-AES). A preconcentration procedure of the analytes was carried out using NSTD as a solid-phase extractant before their determination by ICP-AES. The optimum conditions for adsorption were studied in detail, and under the condition that Au, Ag and Pd ions could be adsorbed and recovered quantitatively. The static adsorption capacities of Au, Ag and Pd on NSTD were 22.63, 14.06 and 11.82 mg/g, respectively. For the elution of gold, silver and palladium, a mixture of 5% thiourea solution and 3 mol L(-1) HNO3 was used. The parameters tested included: pH conditions, contact time of the analytes with NSTD, flow rate, adsorption capacity and sorption kinetics. According to the definition of IUPAC, the detection limits (3sigma) of this method for Au, Ag and Pd with an enrichment factor of 50 were (0.016), (0.006) and (0.012) microg mL(-1), respectively, the relative standard deviations (RSD) were 8.7%, 4.5% and 7.4%, respectively (n = 6). Some geological samples were determined with satisfactory results.     

Thermal studies on some complexes of Pd(II)

The formulae suggested for a series of complexes of Pd(II) with various amino acids have been verified by thermal methods using a derivatograph. A correlation of the obtained kinetic parameters with the structures suggested by electronic and IR spectra of the substances has been attempted.

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Zusammenfassung Es wurden Formeln für eine Serie von Komplexverbindungen des Pd(II) mit verschiedenen Aminosäuren vorgeschlagen und thermogravimetrisch bewiesen. Die Übereinstimmung zwischen den erhaltenen kinetischen Parametern und den durch ERS und Infrarotspektroskopie angedeuteten Strukturen wurde geprüft.

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Résumé On a vérifié par thermogravimétrie des formules brutes proposées pour les combinaisons complexes du Pd(II) avec divers acides aminés. On a examiné la correlation entre les paramètres cynétiques obtenus et les structures déduites des spectres IR et electroniques.

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The use of chemisorption technologies in separation of multicomponent mixtures of metal ions

The concept of using hemisorption technologies for selective removal of individual ions from multicomponent mixtures was suggested and practically confirmed. Results obtained in experimental separation of the Ni²⁺-Fe³⁺-Pb²⁺ mixture with phosphate sorbents are reported.     

Anion exchange studies of zirconium(iv) in citrate solution separation from mixtures

The anion exchange behaviour of zirconium(IV) in a citrate system is described. Nitric acid, hydrochloric acid, perchloric acid and ammonium chloride were tested as eluants on Dowex ₂₁K column. Zirconium is separated from fission product elements e.g., barium, strontium, cadmium, caesium, molybdate and also from lead.     

Reactivity of oxalates of La(III), Ba(II) and Cu(II) in ternary mixtures

Composites of cuprates of La(III) and Ba(II) were obtained by decomposing mixtures of oxalates of La(III), Ba(II) and Cu(II) prepared in 111 and 123 mol proportions respectively and sintering the oxide products at 1173 K. Reactions studied by TG, DTA and XRD techniques revealed the following features: (i) Decomposition of oxalates of La(III) and Ba(II) is drastically affected in mixtures. Decomposition temperature of organic part in the former (111) is shifted by 100 K while that of BaCO₃ in the case of latter (123) is shifted by 400 K towards lower temperature side. (ii) All exothermic peaks on DTA traces of both the mixtures are allotted to the decomposition of oxalates to Cu₂O, La₂O₂CO₃ and BaCO₃ phases while endothermic peaks around 863 and 1083 K are assigned for BaCuO₂ and La₂CuO₄ phases respectively in the case of former (111) and endothermic peaks at about 1068, 1136 and 1213 K are correlated with BaCuO₂, a composite of La₂O₃, La₂CuO₄ and La_0.5Ba_0.5CuO_3– (0.5) phases and LaBa₂Cu₃O_7– (0) phase respectively in the case of latter (123) and (iii) Lines of all cuprate compounds appear in XRD patterns of those samples preheated at temperatures 873 K. The following reaction is proposed in the case of 123 mixture: Authors are deeply thankful to the Authorities of Department of Atomic Energy (DAE), Goverment of India, for providing the funds for research project and to Professor A. V. Phadke, Department of Geology, University of Poona, for the valuable discussion.     

Photoprocess in AgBr microcrystals in the presence of Pt(II) and Pd(II) complex ions

Results of a systematic study of the chemical sensitization of cubic-faceted AgBr emulsion microcrystals with complex compounds K₂[XY₄] and Na₆[XZ₄] [X = Pd, Pt; Y = Br^?, Cl^?, SCN^?; Z =(SO₃)_2?] were considered. The role of secondary dissociation of complex ions during the chemical sensitizing was established. Conditions were determined in which the compounds specified can be used as chemical sensitizers of AgBr. The effect of these complexes on the basic photographic characteristics was demonstrated.     

Studies on the reaction between mercury(II) and CDTA estimation of metal ions and analysis of cation mixtures

Summary Advantage was taken of the stoichiometric reaction between mercury and CDTA in urotropine buffered media to determine mercury or to back-titrate excess CDTA in the course of estimating a variety of metal ions or analyzing their binary mixtures with one of the alkaline-earth metals by selective pH. The procedures given are simple, rapid and extremely reliable.

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Zusammenfassung Die stöchiometrische Reaktion zwischen Quecksilber und CDTA in urotropingepufferter Lösung kann zur Quecksilberbestimmung oder durch Rücktitration von überschüssigem CDTA zur Bestimmung zahlreicher anderer Metallionen verwendet werden. Binäre Gemische mit Erdalkalien können durch Titration in definiertem pH-Bereich analysiert werden. Die beschriebenen Verfahren sind einfach, zuverlässig und rasch durchzuführen.

     

Simultaneous separation and extraction of Ag(I), Pb(II) and Pd(II) ions by solid phase method and determination of these ions by flame atomic absorption spectrometry

A simultaneous preconcentration and separation method for determination of trace amount of dissolved Ag⁺, Pb²⁺ and Pd²⁺ ions by modified octadecyl silica membrane disks with DBzDA18C6 was developed. The adsorbed metal complexes were eluted from disk with 10?mL of 4?M KCl and determined by flame atomic absorption spectroscopy. Several parameters such as anion effect, pH of sample solution, type of eluent, amount of ligand, sample and elution flow rate were evaluated. The effect of diverse ions on preconcentration was also investigated. A precocentration factor of 110 can easily be achieved depending on the volume of the sample. For 100?mL of the solution the linear dynamic rang were found to be 30–1000, 140–6000, 60–900?μg?l^?1 for Ag⁺, Pb²⁺ and Pd²⁺, respectively. Based on three standard deviation of the blank the detection limit was obtained as 1.8, 8.0 and 4.2?μg?L^?1 for Ag⁺, Pb²⁺, Pd²⁺, respectively. The formation constants of Ag⁺ and Pb²⁺ ions with DBzDA18C6 at 25?°C were determined from the molar conductance–mole ratio data. This method was applied for the determination of Ag⁺, Pb²⁺ and Pd²⁺ in environmental water, tea and soil samples.     

Magnetic separation of heavy metal ions and evaluation based on surface‐enhanced Raman spectroscopy: Copper(II) ions as a case study

A new approach was developed for the magnetic separation of copper(II) ions with easy operation and high efficiency. p‐Mercaptobenzoic acid served as the modified tag of Fe₂O₃@Au nanoparticles both for the chelation ligand and Raman reporter. Through the chelation between the copper(II) ions and carboxyl groups on the gold shell, the Fe₂O₃@Au nanoparticles aggregated to form networks that were enriched and separated from the solution by a magnet. A significant decrease in the concentration of copper(II) ions in the supernatant solution was observed. An extremely sensitive method based on surface‐enhanced Raman spectroscopy was employed to detect free copper(II) ions that remained after the magnetic separation, and thus to evaluate the separation efficiency. The results indicated the intensities of the surface‐enhanced Raman spectroscopy bands from p‐mercaptobenzoic acid were dependent on the concentration of copper(II) ions, and the concentration was decreased by several orders of magnitude after the magnetic separation. The present protocol effectively decreased the total amount of heavy metal ions in the solution. This approach opens a potential application in the magnetic separation and highly sensitive detection of heavy metal ions.     

Anion exchange studies of indium(III) in malonate and ascorbate solutions separation from mixtures

Summary Systematic studies are presented on the anion-exchange behaviour of indium on Dowex 21K in malonic acid and ascorbic acid solutions. Hydrochloric, sulphuric, nitric and perchloric acids, also sodium and ammonium nitrate at different concentrations were tested as eluants in the two systems. Their efficiency was evaluated in terms of elution constants. Methods have been developed for the separation of indium from several elements in malonate as well as ascorbate media with the technique of selective sorption, selective elution or by gradient elution.     

N-Phthaloylglycinate ternary complexes with cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) metal ions and aromatic mono,bi and tridentate amines

Complexes of N-phthaloylglycinate (N-phthgly) and Co^II, Ni^II, Cu^II, Zn^II and Cd^II containing imidazole (imi), N-methylimidazole (mimi), 2,2-bipyridyl (bipy) and 1,10-phenanthroline (phen), and tridentate amines such as 2,2,2-terpyridine (terpy) and 2,4,6-(2-pyridyl)s-triazine (tptz), were prepared and characterized by conventional methods, i.r. spectra and by thermogravimetric analysis. For imi and mimi ternary complexes, the general formula [M(imi/mimi)₂(N-phthgly)₂]·nH₂O, where M = Co^II, Ni^II, Cu^II and Zn^II applies. For Cd^II ternary complexes with imi, [Cd(imi)₃(N-phthgly)₂]·2H₂O applies. For the bi and tridentate ligands, ternary complexes of the formula [M(L)(N-phthgly)₂]·nH₂O were obtained, where M = Co^II, Ni^II, Cu^II and Zn^II; L = bipy, phen, tptz and terpy. In all complexes, N-phthgly acts as a monodentate ligand, coordinating metal ions through the carboxylate oxygen, except for the ternary complexes of Co^II, Ni^II and Cu^II with mimi and Cu^II and Zn^II with imi, where the N-phthgly acts as a bidentate ligand, coordinating the metal ions through both carboxylate oxygen atoms.