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Abstract  

Ferrites have been used to separate a wide range of substances such as dissolved metal species, particulate matter, and organic and biological materials; they have been used almost exclusively for metal waste treatment applications. However, ferrites can be used to remove and concentrate selected trace metals in a wide variety of feed solutions requiring analysis. A brief overview of ferrite properties and recent applications for trace metal recovery and concentration will be presented.

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Abstract  

A wide variety of iron oxides has been used for the removal of radioactive and toxic metals from aqueous solutions. We have utilized natural magnetite and iron ferrite (FeO·Fe2O3) in a batch mode to remove actinides (Pu and Am) from wastewater. Compared to the batch process, enhanced capacity for actinide removal was observed using supported magnetite in a column surrounded by an external magnetic field (0.3 tesla). The enhanced magnetite capacity in the column is primarily due to magnetic filtration of colloidal and submicron actinide particles along with some actinide complex and ion exchange sorption mechanisms. The removal of the magnetic field from around the column and use of a regenerating solution will easily remove the actinides loaded on the magnetite. The magnetic field-enhanced column process is under development for a variety of applications. This paper will review previous work on using ferrites for water treatment and discuss the potential for using the magnetic field-enhanced column process as a pre-analysis separation and concentration method for actinides in groundwater.

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Abstract  

Pellicular, macroreticular and microreticular (gel-type) anion exchange resins were compared for the separation of plutonium from nitric acid solutions of mixed plutonium-uranium. AS Pellionex SAX (pellicular resin) and Amberlite IRA-93 (weak base macroreticular anion exchange resin) were found to have better uranium washing and plutonium eluting characteristics than any of the resins tested. However, the capacity of the pellicular resin was much lower than the other resins.

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Abstract  

To demonstrate the safety performance assessment for the disposal of 134Cs radionuclide in a geological formation, several investigations were required to calculate the possible release of radionuclides into groundwater. This research examined the sorption behavior of radioactive cesium (134Cs) in natural groundwater. Cesium chloride (10-6 to 10-2 mol.l-1) was used as a carrier, traced with 134Cs radionuclide. Distribution coefficients of radiocesium for sorption and desorption were measured on natural soil samples of different grain size fractions (400 to 36 mm). Cesium sorption and desorption were found reversible at cesium chloride concentrations between 10-6 mol.l-1 to less than 10-3 mol.l-1. Sequential extraction procedures showed that the cesium sorption on soils were of various types: those easily desorbed, ion-exchanged, bound to carbonate, iron oxides, and organic matter. To demonstrate the safety performance assessment for the disposal of 134Cs radionuclide in a geological formation, several investigations were required to calculate the possible release of radionuclides into groundwater. This research examined the sorption behavior of radioactive cesium (134Cs) in natural groundwater. Cesium chloride (10-6 to 10-2 mol.l-1) was used as a carrier, traced with 134Cs radionuclide. Distribution coefficients of radiocesium for sorption and desorption were measured on natural soil samples of different grain size fractions (400 to 36 mm). Cesium sorption and desorption were found reversible at cesium chloride concentrations between 10-6 mol.l-1 to less than 10-3 mol.l-1. Sequential extraction procedures showed that the cesium sorption on soils were of various types: those easily desorbed, ion-exchanged, bound to carbonate, iron oxides, and organic matter.

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Abstract  

Separations research at the Rocky Flats Plant /RFP/ has found ways to significantly improve plutonium secondary recovery from nitric acid waste streams generated by plutonium purifications operations. Capacity and break-through studies show anion exchange with Dowex 1×4 /50–100 mesh/ to be superior for secondary recovery of plutonium. Extraction chromatography with TOPO /tri-n-octylphosphine oxide/ on XAD-4 removes the final traces of plutonium, including hydrolytic polymer.

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Abstract  

Separations research at the Rocky Flats Plant /RFP/ has found ways to significantly improve americium removal from nitric acid/7M/ waste streams generated by plutonium purification operations. Partial neutralization of the acid waste followed by solid supported liquid membranes /SLM/ are useful in transferring and concentrating americium from nitrate solutions. Specifically, DHDECMP /dihexyl-N, N-diethylcarbamoylmethylphosphonate/ supported on Accurel polypropylene hollow fibers assembled in modular form transfers >95% of the americium from high nitrate /6.9M/, low acid /0.1M/ feeds into 0.25M oxalic acid stripping solution. Maximum permeabilities were observed to be 0.001 cm sec–1, consistent with typical values for other systems. The feed:strip volume ratio shows an inverse relationship to the fraction of metal ion transferred. Cation exchangers may be used to concentrate americium from the strip solution. Furthermore, OØD/iB/CMPO /or CMPO/ /octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide/ has been tested in an extraction chromatography mode. Preliminary results show CMPO to be effective in removing americium if the feed is neutralized to 1.OM acidity and iron/III/ is complexed with 0.20M oxalic acid.

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Abstract  

Besides a brief review of the INEEL, examples of chemical separation activities in environmental management are presented in this paper. Under development at the INEEL are separation technologies for the treatment of radioactive wastes, including highly radioactive liquid wastes, solid calcined wastes and mixed wastes, as well as contaminated groundwater and soils. An overview of these technologies, specific applications of the technologies, and the benefits from their use are discussed.

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Abstract  

Phosphate rock (Pho-ore) is the starting raw material used in manufacturing of most phosphate products. This material contains phosphorous, natural uranium, thorium potassium radionuclide and other trace elements. Single super phosphate powder (SSPho-P), single super phosphate granules (SSPho-G), and triple super phosphate (TSPho) are the common phosphate products produced along with phosphogypsym (CaSO4) as a waste product. Since these materials are industrially manufactured by the reaction of the phosphate ore with phosphoric and sulphuric acids, these products and the waste product are extremely acidic. Pho-ore, SSPho-P, SSPho-G, TSPho and CaSO4 samples were used in our study. Chemical analyses showed that these phosphate samples contain phosphorous, iron, aluminum ions and traces of uranium ions. Accumulation of the fertilizers on soils usually transfers some of these ions from the fertilizer materials to the soil/water interfaces. The migration of uranium U(VI), P, Al and Fe in subsurface soils was found to be strongly influenced by the sorption/desorption reaction at the solid/water interfaces. Thus, dissolution of these ions in soil/water phases is very important. Speciation of U(VI), P, Al and Fe in soil/water phases were calculated using a geochemical code (MINTEQA2). This study was conducted to determine sorption properties and the surface electrical properties of these ions at the soil samples.

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Abstract  

Extraction systems with two aqueous phases based on concentrated solutions of sodium carbonate and polyoxonium compounds (PEG 3000, Slovafol 910 and 18-crown-6) have been used for the extraction of Cs, Sr and Eu. Besides the variation of PEG and Slovafol, the effect of dicarbollylcobaltate anion, xylenol orange, thymolphthalexone and CDTA on fission product partion has been studied.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: T. Braun, P. Bull, J. Fardy, I. Haiduc, F. Macasek, W. McDowell, N. Misak, J. Navratil, and T. Sato

Abstract  

Some recent developments in separation techniques with applications to nuclear analytical methods are summarised. The projects discussed are part of an International Atomic Energy Agency Coordinated Research Programme and cover both fundamental studies of the mechanism of various separation processes, and practical applications of novel radiochemical procedures. The processes include methods of sorption, ion exchange and solvent extraction. Applications to neutron activation analysis, photon electron rejecting alpha liquid scintillation spectrometry and X-ray fluorescence spectrometry are described.

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