Chromatographic Separation Of Uranium Research Articles

Chromatographic separation of uranium(VI) from other elements using L-valine and poly[dibenzo-18-crown-6

A selective and effective column chromatographic separation method has been developed for uranium(VI) using poly[dibenzo-18-crown-6]. The separation was carried out in L-valine medium. The adsorption of uranium(VI) was quantitative from 1.0 × 10−4 to 1 × 10−1 M of L-valine. Amongst various eluents 2.0–8.0 M hydrochloric acid, 1.0–4.0 M sulfuric acid, 1.0–5.0 M perchloric acid, 6.0–8.0 M hydrobromic acid and 5.0–6.0 M acetic acid were found to be efficient eluents for uranium(Vl). The capacity of poly[dibenzo-18-crown-6] for uranium(VI) was 0.25 ± 0.01 mmol/g of crown polymer. Uranium(VI) was separated from number of cations and anions in binary mixtures in which most of the cations and anions show a very high tolerance limit. The selective separation of uranium(VI) was carried out from multicomponent mixtures. The method was extended to determination of uranium(VI) in geological samples. The method is simple, rapid and selective with good reproducibility (approximately ∼2%).

Sorption profile and chromatographic separation of uranium (VI) ions from aqueous solutions onto date pits solid sorbent

The retention profile of uranium (VI) as uranyl ions (UO 2 2+) from the aqueous media onto the solid sorbent date pits has been investigated. The sorption of UO 2 2+ ions onto the date pits was achieved quantitatively (98 ± 3.4%, n = 5) after 15 min of shaking at pH 6–7. The sorption of UO 2 2+ onto the used sorbent was found fast, followed by a first order rate equation with an overall rate constant, k of 4.8 ± 0.05 s −1. The sorption data were explained in a manner consistent with a “solvent extraction” mechanism. The sorption data were also subjected to Freundlich isotherm model over a wide range of equilibrium concentration (1–20 μg mL −1) of UO 2 2+. The results revealed that, a “dual-mode” of sorption mechanism involving absorption related to “solvent extraction” and an added component for “surface adsorption” is most likely operated simultaneously for uranyl ions uptaking the solid sorbent. The thermodynamic parameters (−Δ H, Δ S and Δ G) of the uranyl ions uptake onto the date pits indicated that, the process is endothermic and proceeds spontaneously. The interference of some diverse ions on the sorption UO 2 2+ from the aqueous media onto the date pits packed column was critically investigated and the data revealed quantitative collection of UO 2 2+ at 5 mL min −1 flow rate. The retained UO 2 2+ was recovered quantitatively with HCl (3.0 mol L −1) from the column at 5 mL min −1 flow rate. The mode of binding of the date pits with UO 2 2+ was determined from the IR spectral date bits before and after extraction of uranium (VI). The height equivalent (HETP) and the number ( N) of theoretical plates of the date pits packed column were determined from the chromatograms. Complete retention and recovery of UO 2 2+ spiked to wastewater samples by the date pits packed column was successfully achieved. The capacity of the used sorbent towards retention of uranium (VI) from aqueous solutions was much better than the most common sorbents.

Synthesis, characterization and applications of poly(β-styryl) hydroxamic acids

The synthesis and properties of poly(β-styryl) hydroxamic acids as ion exchange resins are described. The chelating properties of the resins are determined. The chromatographic separation of uranium(VI) from lanthanides is also described.

Extraction chromatographic separation of uranium and fission products in the system di-(2-ethylhexyl)phosphoric acid-hydrochloric acid

An elution scheme has been developed for obtaining separate fission product and uranium fractions using extraction chromatographic techniques with di-(2-ethylhexyl)phosphoric acid as a stationary phase and HCl of varying concentration as eluting agent. The investigations have been concentrated on the fission products cerium, europium, molybdenum and zirconium. The elution of zirconium by oxalic acid is characterized by a peak broadening and has been explained by considering extraction kinetics. Experiments on column performance with different support materials have proved Ftoroplast-4 and Celite Hyflo Super Cel to be capable of giving column fillings with equal separation ability.

Chromatographic separation of uranium (VI) by use of gel containing titanium hydroxide

Chromatographic separation of uranium (VI) by use of gel containing titanium hydroxide

Chromatographic separation of uranium from excess accompanying elements in a medium of diethylenetriamine-N,N,N',N",N"-pentaacetic acid

Chromatographic separation of uranium from excess accompanying elements in a medium of diethylenetriamine-N,N,N',N",N"-pentaacetic acid

The chromatographic separation of uranium, thorium and rare earths by means of paper treated with a liquid anion exchanger

The chromatographic separation of uranium, thorium and rare earths was carried out by using a paper treated with tri-n-octylamine (TNOA). Solutions containing HNO/sub 3/, LiNO/sub 3/, NH/sub 4/NO/sub 3/ NsNO/sub 3/, Ca(NO/sub 3/)/ sub 2/ and Al(NO/sub 3/)/sub 3/ were used as eluants. This type of chromatographic separation is analogous to ion exchange on anionic resins or with liquid amines. The effects of the various parameters on the R values are examined. The separation of thorium, uranium and lanthanum with hydrochloric solutions, on paper treated with tri-n-octyl-phosphine oxide was investigated. The possibility of using columns filled with cellulose powder treated with TNOA, as anionic resin columns is also anticipated. (auth)

Chromatographic separation of uranium from iron and thorium with hydroxamized filter paper

Filter paper is oxidized with nitrogen dioxide and hydroxamized with hydroxylamine. Uranyl ions give a yellow color and ferric ions give a brown color on this hydroxamized paper. Uranium (30 to 150 mu g) is separated as a yellow band from iron (<1 mg) and thorium (<250 mu g) by ascending chromatography on a strip of hydroxamized paper with 2.5% ammonium carborate solution as a developer. After development for 180 min the band is removed, the separated uranium is extracted with dilute hydrochloric acid from the strip, and determined spectrophotometrically with neothorone using 600 m mu light. (auth)