Uranyl removal

Raffinate acid from the first cycle, containing approximately 7 to 14 g/L U Og is then reoxidized and re-extracted in the second, purification cycle using a solvent containing 0.3 Af D2EHPA and 0.075 AfTOPO. The loaded solvent is washed with iron-free acid to remove iron and then with water to remove extracted and entrained acid. The solvent is stripped with ammonium carbonate [506-87-6] to yield ammonium uranyl tricarbonate [18077-77-5] which is subsequendy calcined to U Og (yellow cake). The stripped solvent is regenerated with mineral acid before recycling (39). 

A second method of solving the kinetics dilemna consists of driving a polymerization reaction to completion by removing a volatile coproduct as in the case of uranyl dicarboxylate polymers from uranyl acetate and the dicarboxylic acid (5) ... 

K. M., Gu, H.W., Zhang, B Zhang, X.X. and Xu, B. (2006) A biocompatible method of decorporation bisphosphonate-modified magnetite nanoparticles to remove uranyl ions from blood. Journal of the American Chemical Society, 128 (41), 13358-13359. 

The removal of Pb by Brevibacterium sp strain PBZ was markedly enhanced by the presence of glucose (Simine et al. 1998). Desorption of the metal by EDTA restored the binding capacity of the cells. U(VI) could be desorped from the cell surface of B. cereus by citric acid or sodium bicarbonate with the formation of water-soluble complexes although U(VI) was strongly bound on the cell surface of the bacteria. However, uranyl in... 

Aqueous uranyl sulfate system, 25 429 Aqueous varnish removal systems, in fine art examination/conservation, 11 413 Aqueous zinc chloride, as cellulose solvent, 11 272... 

If phosphate buffer has been used, rinse tissue five times over a period of 1 h in 0.1 Mmaleate buffer containing 3.5% sucrose, pH 6.5, to remove phosphate ions. Stain the tissue en bloc with 2% uranyl acetate in maleate-sucrose buffer, pH 6.0, for 2 h at 4°C in the dark. 

Carraher and coworkers employed the last two processes to recover the uranyl ion. The uranyl ion is the natural water-soluble form of uranium oxide. It is also toxic, acting as a heavy metal toxin. Through the use of salts of dicarboxylic acids and poly(acrylic acid), the uranyl ion was removed to 10 M with the resulting product much less toxic and convertible to uranium oxide by heating. 

Figure 7. This microfibril was treated with hot trifluoroacetic acid to remove hemicellulose and was then negatively stained with 2% uranyl acetate in Figure 7a. The optical diffraction pattern in Figure 7b was only of the upper microfibril showing the 33A spacing. In Figure 7b the submicrofibrils cross the TEM microfibril axis at a 45° 5° angle. (7a reproduced with permission from Ref. 1. 1987 Elsevier Science Publishers B. V.)...

Quantitative removal of uranyl ion, UO2, from aqueous soluhons (well water)was demonstrated using the standard chromatography technique. Solutions of uranyl acetate (50 ppm)... 

Triammino-uranyl Nitrate, [U02(NH3)3](N03)2, is produced from the diammino-derivative by keeping it in a closed flask with ammonia gas till the weight becomes constant, and thereafter removing the excess of ammonia in vacuo. It is a comparatively stable orange-yellow powder, and may be kept unaltered in a closed vessel for some time. 

Procedures for separation of copper from nickel, and nickel from magnesium, have been developed using 8-hydroxyquinoline-functional resins (74MI11107). Also noteworthy is a separation of uranyl ions from sea water in which 84% of the uranium was removed <77CI(L)634). 

Fig. 24. Electronmicrograph of crystals formed from 2 molar CaClj extracts o( Mercenaria mercenaria following removal of salt. Negatively stained with Kf uranyl acetate (x 50000). A characteristic staining pattern is developed with well-defined periodicities. This material represents the MM. The crystals and staining pattern closely resemble tropomyosin-troponin paracrys-tals,93>...

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