Extraction of uranium (VI) by 1.1M tri-n-butylphosphate/ionic liquid and the feasibility of recovery by direct electrodeposition from organic phase

Pulletikurthi, Giridhar; Venkatesan, K. A.; Subramaniam, Sangeetha; Srinivasan, T. G.; Rao, P. R. Vasudeva

doi:10.1016/j.jallcom.2007.03.115

Cited by 133 publications

(86 citation statements)

References 29 publications

(35 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6.1 as a function of initial nitric acid concentration for TBP/[C 4 mim][NTf 2 ] (30 % v/v). As it can be seen the distribution coefficient is high at low nitric acids concentrations (0.01 M), decreases to its lowest level at [HNO 3 ] aq,init = 1 M, followed by an increase up to concentration of 3 M. Similar trends were found by other investigators as well (Giridhar et al 2008, Billard et al 2011b) for [C 4 mim][NTf 2 ], even though some experimental details, i.e. dioxouranium(VI) concentration, temperature, and experimental procedure for phase preparation were not the same from one work to the other.…”

supporting

confidence: 88%

Liquid-Liquid Mass Transfer Using Ionic Liquids

Tsaoulidis

2015

Studies of Intensified Small-Scale Processes for Liquid-Liquid Separations in Spent Nuclear Fuel Reprocessing

View full text Add to dashboard Cite

In this chapter the mass transfer during liquid-liquid plug flow in small channels is presented. The extraction of dioxouranium(VI) ions from nitric acid solutions into TBP/IL mixtures (Table 3.2), relevant to spent nuclear fuel reprocessing was investigated. A schematic of the experimental set-up used for the extraction of dioxouranium(VI) ions from nitric acid solutions by TBP dissolved in ionic liquids is depicted in Fig. 3.2 (Sect. 3.4).The effects of initial nitric acid concentration, residence time, flow rate ratio, mixture velocity, and ionic liquid type are discussed. In addition, the effects of scaling up on the mass transfer performance of the extractor are examined. The overall mass transfer coefficients (k L α) obtained for the three different channel sizes varied between 0.049 and 0.312 s −1 . Finally, the possibility of industrial application of the intensified extraction units is discussed. Extraction of Dioxouranium(VI) at EquilibriumAll equilibrium extractions were carried out at room temperature with 1:1 ionic liquid to aqueous phase ratio. The ionic liquid in its pure state absorbs a small amount of water depending on the initial nitric acid concentration that can vary from 17000 to 25000 ppm for 0.01 to 3 M nitric acid concentration, respectively. In the experiments a solution of 30 % (v/v) TBP in ionic liquids was prepared and equilibrated with the nitric acid solution at the required concentration by mechanical shaking at various time lengths. Saturation was confirmed by measuring the viscosity for both pure and saturated ionic liquid with a digital Rheometer DV-III Ultra (Brookfield). It was found that the ionic liquid was saturated after about 45 min shaking. Then, the two phases were separated and the pre-equilibrated

show abstract

supporting

confidence: 88%

Liquid-Liquid Mass Transfer Using Ionic Liquids

Tsaoulidis

2015

Studies of Intensified Small-Scale Processes for Liquid-Liquid Separations in Spent Nuclear Fuel Reprocessing

View full text Add to dashboard Cite

show abstract

“…[31] Those data are compared in Figure 1w ith those obtained by contacting the same aqueous phases with aT BP/RTIL phase ([TBP] = All these data werea cquired in the absence of U VI .A lthough some researchers have shown that large amounts of metal may influence the distribution of all compoundsi nb iphasic systems, [40] we consider our data to be applicable to Ue xtraction, because Uranium distribution coefficients (D U )v alues are identical from U = 10 À2 m down to trace amounts. [25,29] As am atter of fact, our uranyl extraction data published previously [29] were obtained for [UO 2 2 + ] eq,ini = 10 À3 m,w hereas the characterization of extracted species had to be acquired at higher uranium concentrations ([UO 2 2 + ] eq,ini = 10 À3 m), owing to the detectionl imits.…”

Section: Effect Of Tbp In the Rtil Phase On The Solubility Of Rtil Iomentioning

confidence: 85%

“…This separation is made by the formation of the neutrals olvate UO 2 (NO 3 ) 2 (TBP) 2 .Replacing the kerosene phase by an imidazolium-based or tetraalkyl-based RTIL induces ac hange in the uranium(VI)d istribution coefficient curve as af unction of the acid concentration, which exhibits a" boomerang" shape. [25,26] At low acid concentrations, the extraction of uranium is strongly dependento nt he length of the imidazolium or tetraalkylammonium alkyl chains, as shown by Dietz and Stepinski [27] and Murali et al [28] Several mechanisms were proposed to explain the data. At low acid concentrations,b oth groups are in agreement about the extraction of the solvate [UO 2 À by an anion exchange with one RTIL anion at high acid concentrations.…”

Section: Introductionmentioning

confidence: 96%

Insights into the Mechanism of Extraction of Uranium (VI) from Nitric Acid Solution into an Ionic Liquid by using Tri‐n‐butyl phosphate

et al. 2015

View full text Add to dashboard Cite

We present new results on the liquid-liquid extraction of uranium (VI) from a nitric acid aqueous phase into a tri-n-butyl phosphate/1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (TBP/[C4 mim][Tf2 N]) phase. The individual solubilities of the ionic-liquid ions in the upper part of the biphasic system are measured over the whole acidic range and as a function of the TBP concentration. New insights into the extraction mechanism are obtained through the in situ characterization of the extracted uranyl complexes by coupling UV/Vis and extended X-ray absorption fine structure (EXAFS) spectroscopy. We propose a chemical model to explain uranium (VI) extraction that describes the data through a fit of the uranyl distribution ratio DU . In this model, at low acid concentrations uranium (VI) is extracted as the cationic complex [UO2 (TBP)2 ](2+) , by an exchange with one proton and one C4 mim(+) . At high acid concentrations, the extraction proceeds through a cationic exchange between [UO2 (NO3 )(HNO3 )(TBP)2 ](+) and one C4 mim(+) . As a consequence of this mechanism, the variation of DU as a function of TBP concentration depends on the C4 mim(+) concentration in the aqueous phase. This explains why noninteger values are often derived by analysis of DU versus [TBP] plots to determine the number of TBP molecules involved in the extraction of uranyl in an ionic-liquid phase.

show abstract

“…This organic extractant has very high affinity towards uranium, plutonium, thorium, zirconium, and so forth and hence is used frequently for their separation as well as purification. [15][16][17] The high affinity of TBP towards uranium is due to presence of P═O bond in it, which forms complex with uranyl ion (UO 2…”

Section: Introductionmentioning

confidence: 99%

Improved approach for the determination of low‐Z elements in uranium samples using a vacuum chamber TXRF spectrometer

2017

View full text Add to dashboard Cite

Total reflection X-ray fluorescence (TXRF) method for the determination of low atomic number (Z) elements Na (Z = 11) to Ca (Z = 20) using Cr Kα excitation, vacuum atmosphere sample chamber, and ultrathin window detector of a low Z-high Z TXRF spectrometer has been developed. The earlier reported problem in determination of Al, due to interference of U Mα escape peak with Al Kα, was taken care by more intense solvent extraction-based separation of uranium matrix from the sample solutions. Any dissolved tri-n-butyl phosphate having traces of uranium left after solvent extraction was removed from the sample solutions by equilibrating with n-dodecane. This approach resulted in the betterment of analytical results. The method developed was validated by analyzing three Certified Reference Materials for trace metals in uranium oxide, developed by Department of Atomic Energy, Government of India. The TXRF determined results were found to have an average precision of 8.0% (1σ, n = 3) and the average deviation of the TXRF determined values from the certified concentrations was 7.3%.

show abstract

Extraction of uranium (VI) by 1.1M tri-n-butylphosphate/ionic liquid and the feasibility of recovery by direct electrodeposition from organic phase

Cited by 133 publications

References 29 publications

Liquid-Liquid Mass Transfer Using Ionic Liquids

Liquid-Liquid Mass Transfer Using Ionic Liquids

Insights into the Mechanism of Extraction of Uranium (VI) from Nitric Acid Solution into an Ionic Liquid by using Tri‐n‐butyl phosphate

Improved approach for the determination of low‐Z elements in uranium samples using a vacuum chamber TXRF spectrometer

Contact Info

Product

Resources

About