Extraction of Uranium from Aqueous Solutions by Using Ionic Liquid and Supercritical Carbon Dioxide in Conjunction

Wang, Joanna Shaofen; Sheaff, Chrystal N.; Yoon, Byunghoon; Addleman, R. Shane; Wai, Chien M.

doi:10.1002/chem.200801415

Cited by 63 publications

(36 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We find that the Frenkel line can have similar trend as the melting line above the critical pressure. Moreover, we discuss the relationship between unexplained solubility maxima and Frenkel line, and propose that the Frenkel line corresponds to the optimal conditions for solubility.Recently, there has been a dramatical increase of using supercritical fluids in extraction and purification applications, including in food, nuclear waste, petrochemical and pharmaceutical industries [1][2][3][4]. Supercritical fluids attract significant attention due to their extremely good dissolving power and "tunable" properties.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Frenkel line and solubility maximum in supercritical fluids

et al. 2015

View full text Add to dashboard Cite

A new dynamic line, the Frenkel line, has recently been proposed to separate the supercritical state into rigid-liquid and non-rigid gas-like fluid. The location of Frenkel line on the phase diagram is unknown for real fluids. Here, we map the Frenkel line for three important systems: CO2, H2O and CH4. This provides an important demarcation on the phase diagram of these systems, the demarcation that separates two distinct physical states with liquid-like and gas-like properties. We find that the Frenkel line can have similar trend as the melting line above the critical pressure. Moreover, we discuss the relationship between unexplained solubility maxima and Frenkel line, and propose that the Frenkel line corresponds to the optimal conditions for solubility.Recently, there has been a dramatical increase of using supercritical fluids in extraction and purification applications, including in food, nuclear waste, petrochemical and pharmaceutical industries [1][2][3][4]. Supercritical fluids attract significant attention due to their extremely good dissolving power and "tunable" properties. The solubility of supercritical fluids depend on density and diffusivity. Supercritical fluids combine the best of both worlds: high density of liquids and large diffusion constants of gases. Moreover, both of those properties can be tuned over a wide range pressure and temperature above the critical point, optimizing their dissolving ability.Carbon dioxide, water and methane are three most commonly used supercritical fluids. In particular, H 2 O and CO 2 , are both abundant, non flammable and non toxic. They are also "non-polar" and "polar" solvent, respectively, so they can dissolve "polar" and "non-polar" solutes, respectively. The critical temperature (T c ) of CO 2 is at 304 K, which is near the room temperature, and the critical pressure (P c ) is 74 bar, which is also accessible. Additionally, CO 2 can be used with co-solvents to modify it into "polar" solvent.The solubility of variety of solutes have been measured in supercritical CO 2 near the T c as a function of pressure [1]. Interestingly, the experiment show intriguing solubility maxima above critical temperature: solubility first substantially increase with pressure, followed by its decrease at higher pressure [5][6][7][8][9][10][11][12]. This effect is not currently understood theoretically. Understanding it would lead to more efficiently use of supercritical fluids. More generally, it is often acknowledged that wider deployment of supercritical fluids and optimizing their use would benefit from a theoretical guidance [1,2].Until recently, supercritical state was believed to be physically homogeneous, which means that moving along any path on a pressure and temperature above the critical point does not involve marked or distinct changes. The Frenkel line has recently been proposed, which separates two dynamically distinct states: the gas-like regime where particle only have diffusive motion and the liquidlike regime where particle combine both solid-like quasiharmon...

show abstract

mentioning

confidence: 99%

“…Recently, there has been a dramatical increase of using supercritical fluids in extraction and purification applications, including in food, nuclear waste, petrochemical and pharmaceutical industries [1][2][3][4]. Supercritical fluids attract significant attention due to their extremely good dissolving power and "tunable" properties.…”

mentioning

confidence: 99%

Frenkel line and solubility maximum in supercritical fluids

et al. 2015

View full text Add to dashboard Cite

show abstract

“…6.2. The initial dioxouranium(VI) solutions show characteristic absorption bands similar to those described in the literature for dioxouranium(VI) ions in aqueous solutions (Wang et al 2009). As it can be seen, the shifts in the absorption peaks with nitric acid concentration are negligible, i.e.…”

mentioning

confidence: 86%

“…the peak at 414 nm with 0.01 M nitric acid has shifted to 415 nm and to 416 nm as the nitric acid concentration is increased to 1 M and 3 M, respectively. This slight shift is probably due to the formation of dioxouranium(VI) nitrate complexes in the acid solution (Wang et al 2009).…”

mentioning

confidence: 99%

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

“…Dissolution of uranium oxides in sc-CO 2 using TBP-nitric acid complexes to form UO 2 (NO 3 ) 2 (TBP) 2 illustrated by the two-loop three phases extraction system shown in Figure I-1. 6 The IL-sc-CO 2 coupled extraction is based on the fact that sc-CO 2 dissolves effectively in IL and the solubility of IL in sc-CO 2 is negligible. The advantages of this new IL-sc-CO 2 coupled extraction technique include: (1) radionuclides from the aqueous wastes can be transferred to and concentrated in an ionic liquid under ambient temperature and pressure, (2) no loss of the IL occurs in the sc-CO 2 back-extraction process and no organic solvent is introduced into the ionic liquid phase, and (3) after the back-extraction step, the IL may be reused and the CO 2 also recycled after precipitation of the solutes by pressure reduction.…”

Section: Chapter I Introductionmentioning

confidence: 99%

Ionic Liquid and Supercritical Fluid Hyphenated Techniques for Dissolution and Separation of Lanthanides, Actinides, and Fission Products

Wai¹,

Mincher²

2012

View full text Add to dashboard Cite

Extraction of Uranium from Aqueous Solutions by Using Ionic Liquid and Supercritical Carbon Dioxide in Conjunction

Cited by 63 publications

References 22 publications

Frenkel line and solubility maximum in supercritical fluids

Frenkel line and solubility maximum in supercritical fluids

Liquid-Liquid Mass Transfer Using Ionic Liquids

Ionic Liquid and Supercritical Fluid Hyphenated Techniques for Dissolution and Separation of Lanthanides, Actinides, and Fission Products

Contact Info

Product

Resources

About