M. T. Ganzerli Valentini

Adsorption of monovalent ions on zinc ferrocyanide

Abstract The adsorption from different solutions of caesium, rubidium, potassium, sodium, lithium, silver and mercury (I) on zinc ferrocyanide has been studied. The preparation of the adsorber and its characterization are presented and discussed. The sorption of the alkali metals appears to proceed by an ion-exchange mechanism in NH4NO3 solutions. In HNO3 solutions oxidation to zinc ferricyanide and the destruction of the adsorbed species influence the behaviour of the cations.

Copper hexacyanoferate(II) and (III) as trace cesium adsorbers from natural waters

A description is given of the preparation of copper hexacyanoferrate(II) supported on silica granules. The material in this form is suitable for use as adsorber in batch for concentrating trace cesium from cea water. A modified procedure for collecting cesium from large volumes of river water consists in the use of a column filled with the absorber that is oxidized to copper hexacyanoferrate(III) prior to use.

Characterization of copper hexacyanoferrate(II) and (III) with reference to their use as cesium adsorbers

A description is given of the preparation and chemical properties of copper(II) hexacyanoferrate (II) and (III). The first is well known and already used for rapid determination of137Cs in a wide variety of matrices, but the survey reveals that copper(II) hexacyanoferrate(III) is preferable as long as adsorption capacity is concerned. Thermal stability, reactions in acid media and competitive adsorption of K+ and NH4+ ions are discussed for both adsorbers.

A novel approach to Ca-Sr separation in the determination of90Sr using inorganic exchangers: An application to environmental samples

A procedure for90Sr determination in calcium rich samples is presented. It is based on the precipitation of calcium oxalate in homogeneous solution and under controlled conditions to minimize the coprecipitation of strontium. The latter is subsequently separated as carbonate and radiochemical purification is completed by ion exchange chromatography on two inorganic exchangers: PRTD (partially reduced tin dioxide) and CUCR (copper chromate). The procedure was applied to environmental samples such as ashed sediment, fish and vegetable and results are reported.

Characterization of a partially reduced tin(IV) oxide and of its cation exchange properties

A novel type of tin oxide and its cation exchange properties are described. The preparation of the oxide is rather unusual and consists in the precipitation of SnO·xH2O in the presence of sodium nitroprusside and its digestion in the presence of sodium nitrite. The final product is a partially reduced tin dioxide (PRTD) with one out of eight atoms of metal in the lower oxidation state of +2 and a great part of the bound water hydrogen replaced by sodium. Usual applications of commercially available tin dioxide exchangers can be extended to PRTD with remarkable advantages.

A study of copper and cadmium iminodiacetate complexes by ion-selective electrodes and application to cadmium monitoring

The chelating properties of the iminodiacetate ion (IDA2−) towards copper(II) and cadmium(II) were investigated through pM and pH measurements at constant ionic strength of 0.1 M and at 25°C in the pH range 4–9. The acidity constants founds were in good agreement with those already reported but significant differences from reported values were obtained for the stepwise copper complex formation constants, though the overall constant was in good agreement. Evidence is given for the existence of the protonated species CuH (IDA)−2, which proved helpful in explaining the anomalous complexing capacity of IDA in acidic medium. Practical application include the use of IDA for lowering the level of copper interference in monitoring cadmium ion with a cadmium-selective solid-state electrode; this provides reliable measurements which are otherwise impossible.

Synthesis and properties of some hexacyanoferrates(II),(III) of divalent transition metals

Abstract The formation and properties of cobalt, copper and cadmium hexacyanoferrates(II),(III) as well as of mixed cobalt-zinc and copper-zinc hexacyanoferrates(II),(III) were investigated in detail. In most cases the relevant role played by the preparative conditions is emphasized by analytical data and X-ray powder diffraction patterns. As a typical example, cobalt gives cubic hexacyanoferrates(II) containing Na+ or H3O+ which changes structure on heating; cadmium may give five hexacyanoferrates(II) with differing metal and water content, and with different X-ray patterns.

Metal-Humic and Fulvic Acid Interactions in Fresh Water Ultrafiltrate Fractions

Abstract Fresh water samples from Po river (Northern Italy) were filtered and characterized by measuring the most important physico-chemical parameters. The samples were subsequently submitted to ultrafiltration to separate and fractionate the colloidal particle range from > 104 to < 103 M.W. Two different types of ultrafiltration cells were tested; they yielded quite different results due to systematic errors introduced when using the cell operating under pressure. It was found that the largest share of any metal considered was associated with the finest (< 103 M.W.) particle fraction. Correlation analysis applied to analytical data showed that manganese is associated to organic matter in the 103–104 M.W. particle fraction. Positive correlations existing between copper and Apparent Complexing Capacity (ACC) and between cadmium content and Total Organic Carbon (TOC) in the < 103 M.W. particle fraction were also discussed.

Behaviour of uranyl ion in nitric acid solutions with ammonium molybdophosphate

Abstract The behaviour of uranyl ion sorbed on ammonium 12-molybdophosphate in nitric and sulphuric acid solutions was studied under static conditions. The experimental results show that the exchanged species is the hydroxouranyl ion, UO 2 OH + , and that sorption takes place at low acidity. Functional relations have been established describing UO 2 OH + sorption on AMP as a function of the concentrations of nitric and sulphuric acids, ammonium nitrate and uranium in solution.

Ion exchange chromatography on a new form of tin dioxide for the isolation of strontium radioisotopes from fission products: an application to milk samples

An amorphous, partially-reduced tin dioxide, having properties of an inorganic exchanger, was tested for application to fission product separations. Due to the good sorption of both strontium and barium the application of the exchanger to radiostrontium isolation from fission product mixtures is subject to important restrictions. An application to 90Sr determination in milk is proposed.