Anion-exchange behavior of various metals in hydrazoic acid media

The adsorption characteristics for 43 metals on a strongly basic ion-exchange resin Bio-Rad AG1 were examined in 0.5 M hydrazoic acid solution. The distribution coefficients for V(IV), Fe(III), Cu(II), Zn, Se(IV), Mo(VI), Pd(II), Cd, In(III), Rc(VII), Hg(II) and U(VI), which showed very strong adsorption except for Cd, were measured as a function of hydrazoic acid concentration over the range 0.05–0.5 M. Favorable differences in the distribution coefficients allow useful two- and three-component separations such as Co(II)-Fe(III), As(III)-V(IV), Cd-Zn, Cd- Hg(II), Te(IV)-Se(IV), Th-U(VI), Mn(II)-Mo(VI)-Re(VII), to be achieved on a small column.     

Anion-exchange behaviour of metals on deae-cellulose in hydrochloric acid-acetic acid media

The anion-exchange behaviour of 35 metal ion species on a weakly basic cellulosic ion-exchanger (DEAE-cellulose) in mixed hydrochloric acid-acetic acid media has been investigated. The sorption of metal chloro-complexes on DEAE-cellulose is greatly enhanced with increasing concentration of acetic acid. Differences in sorbability of metals allow many useful analytical separations to be conducted on short columns, containing approximately 1 g of DEAE-cellulose(Cl(-)). Procedures for the chromatographic separations of two-, three-, four- and five-component mixtures are given.     

Anion-exchange behaviour of a number of metal ions on DEAE-cellulose in hydrobromic and hydriodic acid media

Summary The adsorption behaviour of 48 metal ions on DEAE-cellulose layers has been investigated in aqueous hydrobromic and hydriodic acid media. R_F values are given as a function of the hydrobromic and hydriodic acid concentration over the ranges 0.01–6 mol dm^–3 and 0.01–3 mol dm^–3, respectively, and are compared with those obtained with Avicel SF. R_F spectra are comparatively simple in both media, reflecting the strong affinity of the bromide and iodide ions to the DEAE-cellulose phase. Pd, Pt, Re, Au and Hg are distributed chromatographically in either system, while most other metal ions exhibit rather extreme R_F values of near unity or zero. Therefore, the selectivity of the systems is particularly high for Pd, Pt, Re, Au and Hg, providing the possibility of their excellent selective separations.     

The chromatography of metals on DEAE-cellulose layers in phosphoric acid media

The adsorption behaviour of forty-eight metals on DEAE-cellulose thin layers has been examined in aqueous phosphoric acid media. R_F values are given as a function of phosphoric acid concentration over the range 0.01–1.0 M and are compared with those obtained in a similar manner with a crystalline cellulose, Avicel SF. Particularly strong retention on DEAE-cellulose occurred for Mo(VI), W(VI), Re(VII), the platinum group metals, Au(III) and Bi(III). Weak to moderate retention was also observed for several metals, such as V(V), Fe(III), Se(IV), In(III), the rare earths and U(VI), at lower concentrations of phosphoric acid (<0.1 M).     

Cation-exchange in oxalic acid-nitric acid media

Summary The adsorption behaviour of 16 elements on the strongly acidic cation-exchange resin AG 50W, X-8 has been examined in mixed oxalic-nitric acid media. The distribution coefficients are presented as a function of nitric acid concentration (0.13.0 M) in 0.05 M oxalic acid solution. There are marked differences in adsorbability between terand quadrivalent metal and bivalent metal groups. The system can be applied to the multielement analysis of manganese nodules for iron, zinc, copper, cobalt, manganese and nickel, coupled with chromatographic elution of bivalent metals with mineral acid-organic solvent mixtures. The versatility of the system is also demonstrated by the analysis of a biological standard reference material, pepperbush, of NIES for the same six elements. The results are in good agreement with the certified values (NIES: National Institute for Environmental Studies, Japan Environment Agency).

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Kationenaustausch in Oxalsäure-Salpetersäure-LösungAnalytische Anwendung zur Bestimmung von sechs Spurenelementen in Manganknollen und Pflanzenmaterial

Zusammenfassung Das Adsorptionsverhalten von 16 Elementen an dem stark sauren Kationenaustauscher AG 50W, X-8 wurde in Oxalsäure-Salpetersäure-Gemischen untersucht. Die Verteilungskoeffizienten werden angegeben als Funktion der Salpetersäurekonzentration (0,13,0 M) in 0,05 M Oxalsäure. Die Adsorbierbarkeit der drei- und viersowie zweiwertigen Metallionen weist deutliche Unterschiede auf. Das Verfahren kann zur Multielementanalyse von Manganknollen auf Fe, Zn, Cu, Co, Mn und Ni angewendet werden. Die Elution der zweiwertigen Metallionen erfolgt mit Gemischen von Mineralsäuren und organischen Lösungsmitteln. Die Vielseitigkeit der Methode wird durch die Analyse eines biologischen Referenzmaterials (Pepperbush, NIES) demonstriert. Die Ergebnisse stimmten mit den zertifizierten Werten gut überein.

     

Anion-exchange behaviour of the platinum metals and gold in hydrochloric acid-organic solvent media

The anion-exchange characteristics of the platinum metals and gold in hydrochloric acid media are described. The distribution coefficients of these elements were measured on the strongly basic anion-exchange resin Dowex 1 x 8 in mixtures of hydrochloric acid with water and several organic solvents, i.e., dimethylformamide, acetone, tetrahydrofuran, dioxan, methanol, acetic acid and pyndine. Based on these data the conditions most suitable for quantitative separation are indicated and discussed.     

Anion-exchange behaviour and separation of metal ions on deae-cellulose in oxalic acid media

The anion-exchange behaviour of 30 metal ions on a weakly basic ion-exchanger (DEAE-cellulose) has been investigated in aqueous oxalic acid media over the concentration range 0.0010-0.50 M. There are marked differences in adsorbability between ter- and quadrivalent metal and bivalent metal groups; the system offers good prospects for group separations. The adsorptions are moderate, generally a few orders of magnitude lower than those on Dowex 1 (a strongly basic resin). Procedures for the separations Se(IV)Se(VI); As(III)As(V); multicomponent separations Mn(II)Co(II)Cu(II)Ti(IV)Zr(IV) and Cd(II)Zn(II)Cu(II), are given to demonstrate the versatility of the system.     

Ion-exchange behaviour of metals on deae-cellulose in methanol-thiocyanate-hydrochloric acid media

Only a few metals can be adsorbed on DEAE-cellulose from aqueous thiocyanate-chloride media. However, several metal ions, including Cu(II), Zn, Cd, In, Bi and U(VI), exhibit enhanced adsorption on DEAE-cellulose from methanol-thiocyanate-hydrochloric acid mixtures. The distribution coefficients for these metals are given as functions of methanol, ammonium thiocyanate and hydrochloric add concentration. Differences in adsorption among metals permit many useful separations, including those of two-, three- and four-component mixtures, on short columns containing 1-1.5 g of DEAE-cellulose.     

Anion-exchange separation of plutonium in hydrochloric-hydrobromic acid media

Plutonium can be rapidly and selectively separated from the elements that interfere in its radiochemical determination, by the use of hydrobromic acid in a hydrohalic acid anion-exchange separation procedure. Plutonium(IV) and (VI) are adsorbed onto the resin column from 9M hydrochloric acid, interfering elements such as americium and thorium are washed from the column with 9M hydrochloric acid, and the plutonium is reduced to plutoniurn(III) and washed from the column with 11M hydrobromic acid. Interfering elements such as uranium and neptunium, which are adsorbed onto the column from 9M hydrochloric acid, are retained there during the hydrochloric and hydrobromic acid washes. This system would also appear to provide the means for effectively separating plutonium from those elements that commonly interfere in such chemical methods of analysis as redox titration.     

Anion-exchange behaviour of several elements in hydrobromic acid-organic solvent media

The anion-exchange behaviour of 19 elements in hydrobromic acid-organic solvent media has been investigated. The batch distribution coefficients of the metal ions were determined in these systems employing the strongly basic anion-exchange resin Dowex 1, x 8. Organic solvents used were methanol, ethanol, n-propanol, isopropanol, methyl glycol, acetone, tetrahydrofuran and acetic acid. The most suitable conditions for some quantitative separations based on these equilibrium studies are indicated and discussed.     

Anion-exchange separation of cadmium in organic solvent-nitric acid media

The anion-exchange separation of cadmium from zinc and aluminium in organic solvent-nitric acid mixtures was studied. The distribution coefficients of the 3 elements in various 90% organic solvcnt-10% 5 N nitric acid media were determined for Dowex I-X8 resin. A 90% ethanol-10% 5 N nitric acid medium was most satisfactory for the quantitative separation of cadmium from zinc and aluminium. The method was applied to the analysis of some copper and aluminium base alloys. Methyl glycol or acetic acid could be used instead of ethanol. Both cadmium and zinc were strongly adsorbed from a 90% propionc acid-10% 5 N nitric acid medium; separation was then effected by gradient elution.     

Chromatographic behaviour of a number of metal ions on DEAE-cellulose layers in thiosulfate media

The adsorption behavior of 47 metal ions on DEAE-cellulose (Cl⁻) has been surveyed in aqueous thiosulfate solution by thin-layer chromatographic technique. The R_f values are measured as a function of thiosulfate concentration (0.010–2.0M) and are compared with those obtained on a microcrystalline cellulose Avicel SF. Generally, the ion-exchange adsorption of metal ions are weak or moderate over the thiosulfate concentration range tested except for a few metal ions like Mo(VI), Sb(III), Bi(III) etc., which have high preference to DEAE-cellulose. A variety of chromatographic distribution exhibited by metal ions allows to develop a number of separations of analytical and radiochemical interest.     

Anion-exchange behaviour of several elements in systems containing formic acid

The anion-exchange characteristics of 27 elements toward the strongly basic anion-exchange resin Amberlite CG-400 in media containing aqueous formic acid and mixtures of formic acid with sodium formate, hydrochloric acid, sodium nitrite, acetone and methanol have been investigated. Possible separations are described and discussed. The quantitative separations achieved are Sr-La, Zn-Cd-Hg, and Ni-Fe.     

Anion-exchange in mixed solvent systems

A quantitative separation scheme for 15 radionuclides is presented. The scheme is based on group separation by means of anion-exchange resins using mixed solvent systems and subsequent separation of the groups into individual components by means of change of both eluting agent and resin type. The optimum working conditions for separation are established. Separation procedures are of good reproducibility and practically quantitative.     

Adsorption behavior of various metals on a weakly basic anion-exchange resin in sulfuric acid media

A systematic study is presented on the adsorption behavior of some 20 metals on a weakly basic condensed phenol resin, Amberlite CG-4B, in sulfuric acid media. The distribution coefficients were determined over a sulfuric acid concentration range of 0.005 M to 2 M. The metals adsorbed are similar to those which exhibit strong adsorption on a strongly basic resin, but the magnitudes of the distribution coefficients and the adsorption sequences differ considerably between the two types of the resin. Several two- and three-component separations of analytical interest are possible. A new method for the separation of titanium(IV) is described; this is based on its high adsorption on CG-4B from sulfuric acid media containing hydrogen peroxide.     

Determination of the stability constant for acetic acid in synthetic seawater media at various temperatures and salinities

The stability constant (association constant) for acetic acid in synthetic seawater was determined for salinities in the range 5 to 40, in 0.4M and 0.7M ionic strength sodium chloride and at temperatures between 5 and 45°C. The minimum in the log K₁ vs. temperature curve is displaced towards higher temperatures as the ionic strength of NaCl increases. For synthetic seawater solutions, H is independent of temperature but does depend on salinity.     

Thin-layer chromatography of inorganic lons phosphate on cellulose in acetic acid and in acetic acid-ammonium acetate media

Summary Systematic study for the chromatographic behaviour of 49 inorganic ions has been carried out on cellulose phosphate layer in acetic acid and acetic acid — ammonium acetate media. Feasibilities for the effective separations of analytical interest are demonstrated on the 0.25 mm layer in both media.     

Thermal behaviour of acidic salts of mixed tetravalent metals

The mixed amorphous glassy-type zirconium-titanium phosphates contain various quantities of adsorbed water per molecule unit. Pure zirconium phosphate lost the structural water in two steps. This character disappeared with increasing titanium content. However, glassy titanium phosphate lost its water in two steps at lower temperature in comparison with glassy zirconium phosphate.

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Zusammenfassung Das gemischte amorphe Zirkonium-Titan-Phosphat enthält pro Moleküleinheit verschiedene Mengen adsorbierten Wassers. Reines Zirkoniumphosphat verliert das strukturelle Wasser in zwei Schritten. Diese Eigenschaft verschwindet mit zunehmenden Titangehalt. Amorphes Titanphosphat verliert sein Wasser in zwei Schritten bei niedriger Temperatur im Vergleich zu amorphem Zirkoniumphosphat.