Separation of antimony from uranium using zirconium phosphate

Summary The distribution behaviour of antimony and uranium between zirconium phosphate and hydrochloric acid solutions of different concentrations has been determined. The effect of organic solvent addition to the aqueous phase on the distribution data has been investigated. In all cases, the separation factors are evaluated and discussed. The best separation factor was achieved using 1M HCl over all organic-aqueous solvent mixtures. Based on these findings, a procedure has been developed for the separation of antimony from uranium using a Chromatographic column loaded with zirconium phosphate and 1M HCl as eluant.

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Zusammenfassung Das Verteilungsverhalten von Antimon und Uran zwischen Zirkonium-phosphat und Salzsäure verschiedener Konzentration wurde bestimmt. Der Einfluß zugesetzten organischen Lösungsmittels auf die Verteilungsdaten wurde untersucht. Die besten Trennungsergebnisse wurden mit 1-n Salzsäure ohne jeden organischen Zusatz erzielt. Auf dieser Grundlage wurde ein Verfahren ausgearbeitet, um mit Hilfe einer mit Zirkoniumphosphat beladenen chromatographischen Säule und mit 1-n Salzsäure als Elutionsmittel Antimon von Uran zu trennen.

     

Composition and structure of zirconium complexes in tributyl phosphate extracts of Zr from concentrated nitric acid solutions

Using quantitative difference IR spectroscopy we have found that the tibutyl phosphate & acts of zirconium from 12–15 M HN03 contain ionic associates [(TBP)₂H⁺]Zr(NO₃)₅ ^– (I) and [TBP· H₃0⁺ (H₂0)_n]Zr(N0₃)₅ ^– (II), where n = 1, 2, as well as the Zr(N0₃)₄(TBP)₂ complex at a lower concentration than (I) and (I.). The equilibrium I II is shifted toward II at higher C_{HNo 3} ⁰ and lower c_Zr ⁰. The structure of associates I and II is discussed.Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, D. I. Mendeleev Moscow Chemical Technological Institute. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 5, pp. 80–89, September–October, 1993.Translated by L. Smolina     

Separation of traces of silver in nitric acid solutions using mercury as collector

Summary Microgram quantities of silver are quantitatively deposited into mercury globules from nitric acid solutions (ca. 1N acidity), leaving large amounts of base metals (e. g., copper, lead, and bismuth) in solution. This separation method has been applied to the atomic absorption spectrometric determination of a few ppm of silver in copper or lead.

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Zusammenfassung Mikrogrammengen Silber werden aus salpetersaurer Lösung (ca. 1-n) quantitativ auf Quecksilbertröpfchen niedergeschlagen, wobei große Mengen unedle Metalle (z. B. Cu, Pb und Bi) in Lösung bleiben. Diese Trennmethode wurde bei der Bestimmung weniger ppm Silber in Kupfer oder Blei durch Atomarabsorption angewendet.

     

Extraction of strontium from nitric acid solutions by selected crown ethers

The extraction of Sr from nitric acid solutions by the crown ethers, 12-crown-4, 15-crown-5, 18-crown-6 and DB 18-crown-6 dissolved in chloroform has been investigated. Sr is reasonably well extracted by 18-crown-6 compared to other crown ethers from different nitric acid solutions. The extraction is strongly dependent on the concentration of HNO₃ and nitrate salts. Preliminary studies indicate that¹³⁷Cs is also extracted to a limited extent by 18-crown-6 from nitrate medium. Stripping of Sr was achieved by an aqueous solution of low acidity, the crown ether being regenerated for subsequent extraction.     

Removal of cesium and strontium from acid solution using a composite of zirconium molybdate and zirconium tungstate

A composite mixture of zirconium molybdate and zirconium tungstate was prepared and studied for the sorption of cesium and strontium as a function of nitric acid, metal ion concentration, time and temperature. The distribution coefficient (K_d) of 7000 ml/g (~90% sorption) and 70 ml/g (~20% sorption) was obtained for the sorption of cesium and strontium in 0.1M nitric acid, respectively. Experimental sorption capacity, b for cesium was found to be 50 mg/g from 0.1M HNO₃ and 30 mg/g for strontium from 0.001M nitric acid. The sorption of strontium on the sorbent was accompanied by the absorption of heat but the sorption of Cs⁺ results in the liberation of heat. Column studies were conducted by following a breakthrough (BT) curve of cesium and strontium up to C/C₀=1 and the results are reported.     

Photo-oxidation of phenol over titania pillared zirconium phosphate and titanium phosphate

The photodegradation of phenol was studied in the aqueous solutions over titania pillared zirconium phosphate and titanium phosphate under solar radiation and compared with that of the UV-radiation (6 W low pressure Hg vapor lamp). This reaction was studied by varying different parameters such as catalyst dose, initial phenol concentration, pH of solution and irradiation time. The degradation rate of phenol was favourable under neutral pH condition. The degradation process approximately obeyed first-order kinetics with apparent rate of degradation constant increasing with decreasing the initial phenol concentration.     

Separation of zirconium from fission products in silica gel—nitric acid systems

A method for the separation of zirconium from fission products based on the system 100–200 mesh silica gel—2.0 M nitric acid is described. Decontamination factors are over 500 for ⁹⁵Nb, ¹⁰⁶Ru, ¹²⁴Sb, ¹³⁷Cs, molybdate and uranium(VI), and the yield of zirconium is 98 %.     

Separation of europium from aqueous solutions using Al3+- and Fe3+-doped zirconium and titanium phosphates

Summary The sorption of europium from aqueous solutions (Eu-concentration: 10 to 250 mg/l) by Fe³⁺- and Al³⁺-doped zirconium- and titanium-phosphates was investigated using a batch technique and ¹⁵²Eu tracer. The initial pH of the solutions was adjusted to 3, 4, 5 and 6. All investigations were performed under constant ionic strength, I=0.15 established by NaCl.<span lang=EN-GB style='font-size:12.0pt;mso-ansi-language:EN-GB'>Although zirconium phosphates generally showed a higher Eu-uptake capacity than the titanium ones, all investigated materials possessed the ability to remove considerable amounts of europium from aqueous solutions. The Eu-sorption properties of the studied phosphate materials<span style='font-size:12.0pt'>seem to be not especially affected by the type of trivalent cations used for the doping (i.e., Al³⁺or Fe³⁺).     

Separation of radioactive yttrium from strontium by means of mono-octyl anilinobenzylphosphonate

Zusammenfassung Die Trennung des radioaktiven⁹⁰Y von Sr mit Monooktyl-anilinobenzyl-phosphonat wurde beschrieben. Y geht aus 0,1- bis 0,01-m Salzsäure quantitativ in die organische Phase über, während Sr in der wäßrigen Phase bleibt. Die Trennung läßt sich entweder aus verd. Yttriumlösung oder bei Vorliegen der trägerfreien Form durchführen. Die Sr-Menge hat keinen Einfluß. Der Trennungsfaktor beträgt 10⁶. Die Reinheit des abgetrennten⁹⁰Y wurde an Hand seiner Abklingkurve geprüft.

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Part of the thesis submitted byN. Vujii in partial fulfilment of the requirements for the degree of Master of Science in Chemistry (M. Sc.) at the Faculty of Pharmacy and Biochemistry, University of Zagreb.     

Extraction of tetravalent berkelium by tributyl phosphate from nitric acid solutions

Extraction of Bk(IV), Ce(IV), Pu(IV) and Zr by tributyl phosphate from 2M to 16M nitric acid solutions has been studied. Using the data on the effect of the extractant, nitric acid and nitrate ion concentrations on the distribution coefficients of Bk(IV) and Ce(IV), the mechanism of Bk(IV) extraction by tributyl phosphate from nitric acid solutions is considered.     

Adsorption and separation behavior of strontium and yttrium using a silica-based bis(2-ethylhexyl) hydrogen phosphate adsorbent

Journal of Radioanalytical and Nuclear Chemistry - (HDEHP?+?Hexa)/SiO2-P, a silica-based adsorbent, was prepared and used to separate Y(III) from a mixed solution of Sr(II) and Y(III)....     

Separation of strontium from calcium by means of anion exchanger and alcoholic solution of nitric acid

A possibility of mutual separation of calcium and strontium on an anion-exchange column has been studied and then used in working out methods of separation of radioactive strontium from natural samples. All examinations, carried out on model systems, showed that calcium could be completely separated from strontium on the column with the anion exchanger Amberlite CG-400 using 0.25M HNO₃ in methanol as eluent. The flow velocity of this eluent in the range between 1 ml/min and 5 ml/min did not influence the efficiency of separation of calcium from strontium. The increase of the concentration of nitric acid in methanol reduced the efficiency of their mutual separation and the increase of exchanger column height neutralized the influence of the increase of acid concentration. Calcium was separated from strontium in the mass concentration ratio (Ca²⁺)/(Sr²⁺) in the range between 11 to 1001. This separation procedure may be used for the isolation of radioactive strontium from real samples instead of using fuming nitric acid.     

Some studies on the extraction of plutonium from phosphate containing nitric acid solutions using DBDECMP as extractant

Extraction studies have been carried out to explore the feasibility of separation of Pu(IV) from phosphate containing analytical wastes generated in the laboratory. Distribution data on the extraction of Pu(IV) from DBDECMP (di-butyl, N,N-diethylcarbamoyl methyl phosphonate) in xylene from an aqueous nitric acid and its mixture with sulfuric as well as with sulfuric and phosphoric acids were obtained. Based on the data obtained, the conditions for the recovery of plutonium from such waste solutions are suggested.     

Composite photocalysts based on the nanostructural titanium dioxide and zirconium phosphate

A series of composite photocatalysts based on titanium dioxide deposited on the surface of a zirconium phosphate support were synthesized under different synthesis and heat-treatment conditions. The study of the photodestruction kinetics of Rhodamine C showed that the synthesized composites possess high photocatalytic activity that is competitive with the activity of a commercial Hombikat UV100 photocatalyst. The composites based on zirconium phosphate treated with isopropanol at the precipitation stage whereupon heated at 550°C exhibit the highest photocatalytic activity after heating at 750°C. It was found that such zirconium phosphate support has the largest specific surface area (270 m²/g). After heating at 550°C, the surface becomes more stable to the subsequent heating to 750°C, which is necessary for the most complete crystallization of TiO₂ ensuring its high photocatalytic characteristics.     

Coprecipitation of radium with calcium and strontium from acid solutions using crown ether and tungstosilicic acid

The coprecipitation of radium with strontium or calcium, 18C6 and tungstosilicic acid was studied. It was determined that radium is coprecipitated with Ca and Sr and mixed compounds are fomed. It was also find the yield of Ra depends on the ratio of stability constants of metals present in a solution with 18C6. The stability constant of Ra with 18C6 was determined using a precipitation method.     

Description of strontium precipitation in highly concentrated nitric acid

Journal of Radioanalytical and Nuclear Chemistry - The precipitation of strontium in highly concentrated nitric acid is often used in standard radiochemical methods for 90Sr separation. In this...     

Separation of yttrium from strontium in the aqueous phase of the water/nitrobenzene system

A rapid separation of carrier-free ⁹⁰Y in the aqueous phase of the water/nitrobenzene extraction system from an ⁹⁰Y/⁹⁰Sr generator is proposed. After a three-stage extraction, the chemical yield of ⁹⁰Y in the final aqueous phase was almost 90%, while the ⁹⁰Sr radionuclide impurity in this phase containing carrier-free ⁹⁰Y was about 10^–10%.     

Separation of microamounts of yttrium from strontium by using nitrobenzene solution of sodium dicarbollylcobaltate in the presence of 18-crown-6

A rapid extraction separation of trace amounts of yttrium from strontium with a nitrobenzene solution of sodium dicarbollylcobaltate (NaDCC) and 18-crown-6 in the presence of tetrasodium salt of ethylenediamine-N,N,N",N"- tetraacetic acid (Na₄L) in the aqueous phase was developed. The separation factor a(Sr/Y) was substantially higher than 10⁶. This water-nitrobenzene extraction system can be applied for efficient separation of carrier-free ⁹⁰Y from ⁹⁰Sr/⁹⁰Y generator.