Plutonium hydroxide

Iodine was determined by an iodometric titration adapted from White and Secor.(3) Instead of the normal Carius combustion, iodide was separated from the samples either by slurrying in 6M NaOH, or by stirring the sample with liquid sodium-potassium (NaK) alloy, followed by dissolving excess NaK in ethanol. Precipitated plutonium hydroxides were filtered. Iodine was determined in the filtrate by bromine oxidation to iodate in an acetate buffer solution, destruction of the excess bromine with formic acid, acidifying with SO, addition of excess KI solution, and titrating the liberated iodine with standard sodium thiosulfate. The precision of the iodine determination is estimated to be about 5% of the measured value, principally due to incomplete extraction of iodine from the sample. 

Taya A, Hotz G, Seidel A. 1986. Biochemical and electron microscopic studies on binding and transport of americium and plutonium hydroxide polymers in bovine alveolar macrophages and rat lungs. J Aerosol Sci 17(3) 370-375. 

In comparison to plutonium both americium and curium are taken up by plants quite readily. The concentration factors for both americium and curium are 10-4 to 10-2 (127). While plutonium has been the subject of considerable research into its environmental impact there have been few investigations into americium and curium. Bondi-etti et al (94) have concluded that plutonium hydroxide polymers would be resistant... 

Table II. Standard Reduction Potentials (at 25°C.) for Various Plutonium Hydroxides in Equilibrium with Pu(OH)4 (21)...

For the reduction of Pu02(0H)2 to Pu(OH)4, if Eh of the solution is less than +0.51 minus 0.059 pH, the Pu(OH)4, is the stable species. Pu(OH)3 cannot exist as a solid form in equilibrium with water because if Eh becomes less than zero minus 0.059 pH, water would be reduced to hydrogen. The pentavalent hydroxide form, PuQ2(OH), is unstable in both acidic and basic aqueous solutions (21) and converts to either the hexavalent or the tetra or trivalent forms because of its E°. Thus, if Eh is greater than 0.51 — 0.059 pH, PuC OHJa will be the stable form, while below this Eh Pu(OH)4 will be, these being the only stable plutonium hydroxides likely to be found in equilibrium with water. The question remains as to the likely Eh to be encountered in natural waters or even under laboratory conditions. Baas Becking, Kaplan, and Moore (1) have collected many reports of Eh values in natural waters. In an... 

Although it is important to understand the mechanisms in the formation of the distribution of sizes among the colloidal plutonium hydroxide particles, the distributions themselves will influence the behavior... 

Felmy A. R., Dhanpat R., Schramke J. A., and Ryan J. L. (1989) The solubility of plutonium hydroxide in dilute solution and in high-ionic-strength chloride brines. Radiochim. Acta 43, 29 - 35. 

Intermediate compound PlutoniumlV oxalate Ammonium diuranate-plutonium hydroxide... 

The presence of DTPA should prevent the formation of plutonium polymer during the transition from pH = 9 to less than pH = 0.3. Above 1 M in hydrogen ion concentration, H5DTPA is no longer very effective as a chelating agent and thus does not affect the Dfs of actinides in the ARALEX process. In addition, DTPA in the Na2C03 scrub also prevents the formation of plutonium hydroxide when macro concentrations of plutonium are present. 

Particularly in the case of plutonium hydroxide, the amount of plutonium solublized from an internal deposit by biological ligands depends upon the oxidation state of the deposited plutonium. The charge to ionic-radius ratio and the tendency towards hydrolysis decreases in the order32 33) ... 

The hydrolytic chemistry of Pu is important in that it affects the behavior and mobility of plutonium in the environment [A2] and in geologically isolated radioactive wastes that may be subjected to slow leaching by ground water. The absorption spectra of the Pu(TV) polymer is similar to that of the plutonium hydroxide precipitate Pu(0H)4 [L4]. Experimental data in Fig. 

Perez-Bustamante, J.A. (1965) Solubility product of tetravalent plutonium hydroxide and study of the amphoteric character of hexavalent plutonium hydroxide. 

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