A Comparative Study of the Synthesis and Ion Exchange Properties of Iodophosphates of Tin(IV), Zirconium(IV) and Iron(III): Separations of Metal Ions on Tin(IV)-iodophosphate Columns

Abstract

Iodates and iodophosphates of tin(IV), zirconium(IV) and iron(III) have been synthesized under varying conditions and studied their ion exchange behaviour. Among the various ion exchangers synthesized, tin(IV)-iodophosphate is chosen for detailed study owing to its highest ion exchange capacity and highest chemical stability. The most stable sample is prepared by mixing 0.1M stannic chloride, 0.1M potassium iodate and 0.1M potassium dihydrogen orthophosphate solutions in the volume ratio 1:1:2 respectively at pH 0–1. It is a monofunctional weak cation exchanger. Its ion exchange capacity for K⁺ is 1.6 meq/dry g. The thermal and chemical stabilities of this material have been determined and compared with Zr(IV)-phosphoiodate. Effect of heating on the properties of tin(IV)-iodophosphate has been determined. To explore the separation potential of tin(IV)-iodophosphate Kd values of different metal ions have been determined in organic solvents. A number of important separations of metal ions of industrial utility have been successfully achieved on the columns of tin(IV)-iodophosphate.     

Sorption Studies in DMSO-NITRIC Acid and DMSO-Acetic Acid Systems and Separation of Metal Ions on TIN(IV)-Iodophosphate

Abstract

Some new samples of tin(IV)-iodophosphate have been synthesized and their ion exchange properties have been studied. Adsorption behaviour of different metal ions on tin(IV)-iodophosphate (TIP₅), in H⁺ form, in different solvent systems have been examined. Kd values of few metal ions, in 4M DMSO medium, have also been determined on the same ion-exchanger in NH⁺ ₄ form. Effect of particle size of tin(IV)-iodophosphate (TIP₅), in H⁺ form, on the Kd values of metal ions has been studied. Separations of a number of metal ions have been achieved on tin(IV)-iodophosphate (TIP₅) columns.     

Quantitative Separation of Pd(II) by TLC of Metal Ions on Cerium (IV) Antimonate

Abstract

A quantitative TLC separation of metal ions using cerium (IV) antimonate as the solid phase are described. Using an acetonitrile- HNO₃ solvent Pb²⁺ can be separated quantitatively (2–10 μg) from several other ions. A quantitative spectrophotometric assay using p-nitroso-dimethylaniline is proposed.     

Sorption preconcentration and separation of Palladium(II) and Platinum(IV) for visual test and densitometric determination

We have demonstrated the advantages of the dynamic preconcentration and separation of Pd(II) and Pt(IV) on paper carriers modified with 3-methyl-2,6-dimercapto-1,4-thiopyrone. The optimal conditions of the solid-phase reaction have been determined in Pd(II) sorption; after its separation Pt(IV), has been preconcentrated by sorption as its dimercaptides. Test scales have been produced for the visual determination of 0.5–40 μg Pd(II) and 1–195 μg Pt(IV) in 10- and 100 mL-samples, respectively. In addition, a procedure of their sorption-chromaticity densitometry determination from a single aliquot portion has been developed with detection limits of 5 and 1 ng/mL, respectively, and a procedure of Pd(II) determination using a test strip (c _min = 0.40 mg/L) has been proposed. The procedures have been applied to the determination of palladium and platinum in electrolytes, sludges, and alloys.     

Donnan Dialysis of Bromocomplexes of Some Platinum Group Metal Ions

Abstract

The separation of bromocomplexes of platinum group metals by Donnan dialysis is demonstrated with both anion and cation exchange membranes. the inclusion of ethylenediamine (en) in the sample improves the separation of Pd(II) from Pt(IV) with experiments performed with an anion exchange membrane and decreases the amount of metal retained on the membrane phase. With a cation exchange membrane, the addition of a ligand such as en is required for transport. With 5.6 mM en in the sample at pH 10, 74% of Pd(II) is transported across an anion exchange membrane into 0.5 M NH4Br after 6 hours while only 8% of the Pt(IV) is dialyzed. Rhodium(III) and iridium(III) behave like Pt(IV). Using a cation exchange membrane under the same conditions except with a 1 hour dialysis results in a 30-fold preferential preconcentration of Pd(II) relative to Pt(IV), and, based on the amount retained in the membrane, a preconcentration of Ir(III) which exceeds that of Pd(ll) and Pt(IV) by factors of 40 and 20, respectively.     

Quantitative Separation of Hg(11) From Several Metal Ions on Zr(IV) Antimonate Papers

Abstract

The chromatographic behaviour of 32 metal ions has been studied on paper Impregnated with Zirconium(IV) antimonate in aqueous HCI and mixed solvent system containing dimethyisul phoxide and dioxane. Several Important binary and ternary separations have been achieved. Quantitative separation of Hg(ll) from Ni²⁺, Pb²⁺, Pd²⁺, Ru³⁺, Rh³⁺, Bi³⁺, Co²⁺, Cd²⁺ and Gd³⁺ is described.     

Electrochromatographic Separation of DMSO Complexes of Metal Ions

Abstract

Electrochromatography of DMSO complexes of fourteen metal ions have been performed in five electrolytes at 100 volts for 3 hrs. The mechanism of migration has been explained and a number of separations of metal-DMSO complexes were achieved.     

Separation of transition metal ions and preconcentration of platinum (IV) and chromium (III) on alumina-immobilized diethylenetriaminepentaacetic acid by ligand exchange

Summary Basic alumina-bonded diethylenetriaminepentaacetic acid (DTPA) has been utilized for the separation and preconcentration of some transition metal ions on the basis of ligand exchange. Breakthrough capacity and rate of sorption have been studied. The distribution coefficients of 16 transition metal ions have been determined in demineralized water, 0.01 M sodium citrate and in four different pH systems. On the basis of differences in Kd values some quantitative separations of metal ions have been achieved. The greater selectivity behaviour (higher Kd values) of the adsorbent for Pt(IV)and Cr(III) has been utilized for their preconcentration in the presence of other metal ions. The method has been employed for the recovery of Pt(IV) and Cr(III) from tapwater and sea-water samples.     

Use of Di(n-butyl) and Di(iso-butyl)dithiophosphoric Acids as Complexing Agents in the TLC Separation of Some d and f Transition Metal Ions

The thin layer chromatographic behavior of U(VI), Th(IV), lanthanides(III), Co(II), Ni(II), and Cu(II) on silica gel H with di(n-butyl) and di(iso-butyl)dithiophosphoric acids as complexing agents in the organic mobile phase has been investigated. The results obtained show that the dithiophosphate anion has a substantial effect on the migration of these metal ions. The presence of electron-donor solvents in the mobile phase increases retention, especially for U(VI), Th(IV), and lanthanides(III). The effect is explained on the basis of greater solubility of the metal chelates of the dithiophosphoric anions in the organic mobile phase, because of a solvation process. Separation was investigated for three groups of metal ions — actinides, lanthanides, and d transition metals. By choice of an appropriate organic mobile phase, separation of the pairs Th(IV)-U(VI), Pr(III)-Sm(III), Sm(III)-Gd(III), and Gd(III)-Er(III) was achieved, as was separation of Co(II), Ni(II), and Cu(II) from each other. A complex separation mechanism based on adsorption-desorption, cation exchange, and extraction is suggested.

     

Separation and Recovery of Some Metal Ions Using Pan Sorbed Zinc Silicate as Chelating Ion Exchanger

Abstract

A new inorganic ion exchanger zinc silicate has been synthesized. Its properties such as ion exchange capacity, heat effect and stability etc. have been studied. Sorption of PAN over zinc silicate formed a chelate ion exchanger which showed greater selectivity for some metal ions especially for Cu²⁺, Ni²⁺, Co²⁺, Fe³⁺, Ag⁺, Ag³⁺ and Pt⁴⁺. Selectivity has been determined on the basis of distribution coefficients of these metal ions. Separations of Pt(IV) from Fe(III), Au(III) from Fe(III), Ag(I) from Cu(II) and Au(III) from Cu(II) have been reported. The recovery of Pt(IV) and Au(III) from dilute solutions has also been studied.     

Chelation and Analytical Application of Thiosemicarbazides Toward Platinum(IV) Ions

N(1)H derivatives of ethyl- and phenyl-thiosemicarbazides have been prepared and identified so as to produce new complexes with H₂PtCl₆. The obtained complexes have been investigated by thermal, magnetic and spectral studies. They were found to be diamagnetic and to have an octahedral structure. The IR data reveal different modes of coordination for the investigated ligands. The thermal decomposition of some complexes ended with PtS₂ as a final product. The formation of a green associate with 1-phenyl-4-ethylthiosemicarbazide (HPETS) was found suitable for the preconcentration and determination of Pt(IV). A simple and effective separation–determination procedure was achieved through the use of the flotation technique. The deprotonation constants of the ligands and the stability constants of the complexes formed in solution were evaluated by electrochemical methods, Methylthiosemicarbazide (HMTS) complexes were found to be the most stable in solution.     

Synthetic Inorganic Ion-Exchangers XV. Thin-Layer Chromatography of Metal Ions on Thorium Tungstate: Quantitative Separation of Hg(II) from Several Other Metal Ions

Abstract

The analytical application of Thorium tungstate as an ion exchanger has been explored by thin-layer chromatographic (TLC) technique. Binder-free thin layers of thorium tungstate have been employed for some important binary and ternary separations. Quantitative separation of Hg(II) from the mixture of several other metal ions has been achieved.     

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.     

Silica Based Double Salts as Cation-Exchangers-I Synthesis and Analytical Applications of Cerium (IV) Phosphosilicatte

Abstract

This paper deals with the synthesis of ceriura(IV) phosphosilicate as a new, reproducible and stable inorganic ion-exchanger. The studies on Its composition, chemical and thermal stability, pH-titration, IE, and TGA have been discussed alongwith the distribution behaviour for metal ions. On the basis of distribution studies some ternary and binary separations of metal ions have been achieved which are Important both analytically and industrially.     

Spectrometric Studies on the Complexation of Pd(II), Fe(III) and Pt(IV) with mandelazo I

Abstract

A spectrometric study of the reaction between Pd(II), Fe(III) and Pt(IV) ions, and Mandelazo I was carried out. The optimum conditions favouring the formation of the complexes are extensively investigated. The stoichiometry of the complexes formed in solution (1:2, 1:1, 1:1), their apparent stability constants (5.45 × 10⁹, 2.39 × 10⁶, 4.12 × 10⁵) and the ranges for obedience to beer's law (0.2 – 6.4, 0.25 – 7.0, 1.5 – 42.0 μg/mL) are reported for Pd(II), Fe(III) and Pt(IV), respectively. The effect of some metal ions including Cu(II), Zn(II), Mn(II), Cd(II), Hg(II), Co(II), Ni(II), Be(II), Al(III), Th(IV) and U(VI), on the maximum absorbance of the formed complexes was also investigated.     

Separation of Pd(II) and Tl (III) from Various Metal Ions on Hydrous Zirconium Oxide Column

Abstract

The utility of hydrous zirconium oxide for the separation of metal ions has been explored. The Kd-values from different concentrations of chloride ions(pH-2) have been determined. On the basis of the sorption data Pd (II) and Tl (III) have been quantitatively separated from a number of metal ions. The representative elution curves are given and the recovery of the metal ions is reported.     

Chromatographic Studies on Hydrous Oxides of Polyvalent Metals. II. Electrochromatographic Studies of Amino Acids on Hydrous Zirconium (IV) Oxide Papers: Separation of Acidic Amino Acids

Abstract

Electrochromatographic behaviour of some amino acids on hydrous zirconium (IV) oxide impregnated papers have been carried out. Five background electrolytes of different pH were used for these studies at fixed potential difference and time     

A Novel Method of Determining Certain Group VIII Metal Ions by Electron Paramagnetic Resonance Measurements

Abstract

Although electron paramagnetic resonance (EPR) has long proven itself a valuable technique for the study of various organic free radicals¹ including those that are biochemically interesting, only recently has it come into use as a convenient and sensitive method for inorganic analysis. Guilbault and coworkers have demonstrated the usefulness of EPR methods for the determination of low concentrations of various ions of the first transition metal series both in aqueous solution^{2, 3, 4} and extracted into organic solvents.⁵ Moyer and McCarthy⁶ have also demonstrated the application of EPR to quantitative inorganic analysis. Inasmuch as the area under the EPR first derivative curve is related to the number of unpaired electrons, this can serve as a measure of the concentration of a relatively large number of inorganic free radicals including most paramagnetic metal ions. Some of the Group VIII metal ions such as Ni(II), Pd(II), and Pt(II), while paramagnetic in their high spin complexes, however, do not exhibit an EPR signal at room temperatures because of their very rapid relaxation times.     

Paper Chromatographic Separations of Metal Ions on Collidinium Tungstoarsenate Papers

Abstract

A systematic study of the chromatography of metal ions on collidinium tungstoarsenate papers has been performed using seven different mixed solvent systems. R_f values of 30 metal ions have been determined by ascending technique and are discussed. The study demonstrates that specific extraction of both Sn(ii) and Sn(iv) is possible in 0.1 mol dm^?3 HNO₃ in 80% (v/v) 1-propanol and their mutual separation can be carried out in solvent system 1 mol dm^?3 HCl in 33% (v/v) 1-propanol. In addition some binary and ternary separation of metal ions have also been achieved on these papers. For a comparison R_f values on plain papers have also been determined in all the solvent systems.     

Free Metal Ion Depletion by Good's Buffers. IV. Bicine 1:1 and 2:1 Complexes with Mg(II), Ca(II), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)

Abstract

The interaction of “Good's” buffers with a variety of metal ions has been assessed.