Aqueous biphasic extraction of uranium and thorium from contaminated soils. Final report

Chaiko, David J.; Gartelmann, J.; Henriksen, J. L.; Krause, Torsten; Vojta, Y.; Thuillet, E.; Mertz, Carol J.

doi:10.2172/146730

Cited by 2 publications

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“…We have recently begun to scaleup ABS processes for ultrafine particle/particle separation by countercurrent extraction using a pilot-scale Karr column. 10 The physicochemical properties of aqueous polyethylene oxide) (PEO) solutions and its lower molecular weight analog, PEG, have been studied extensively and have been reviewed by Bailey and Koleske.11 A host of techniques have been used to probe the aqueous solution structure of PEO, such as light scattering,12•13 Raman spectroscopy,14 electron microscopy,15 small-angle neutron scattering,16•17 viscometry,18•19 and free volume measurements. 20 These studies have revealed many fascinating properties of aqueous PEO solutions.…”

Section: Introductionmentioning

confidence: 99%

A Neutron Scattering Study of Poly(ethylene glycol) in Electrolyte Solutions

Thiyagarajan¹,

Chaiko²,

Hjelm³

1995

Macromolecules

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The solution microstructure of aqueous (D2O) poly(ethylene glycol) (PEG) solutions was determined as a function of polymer concentration and molecular weight in the presence of salts such as NaNOa, NaaCOa, and Na3P04. Measurements were made by using small-angle neutron scattering (SANS).In addition, anion effects on biphase formation were investigated by cloud point measurements in H2O and D2O. In the presence of NaNOa, PEG behaves like a random coil with no evidence of aggregation, whereas the presence of either Na3P04 or NaaCOa leads to aggregate formation. Furthermore, the aggregate size increased with increasing salt concentration until a discontinuity appeared at the point of biphase formation, where the polymers in the PEG-rich phase form an entangled mesh with loss of chain identity. In the monophasic regime, the aggregates were elongated with a radius of approximately 19 Á and a length which varied with salt type and concentration. Analysis of the effects of electrolytes on the cloud points of PEG in H2O and D2O suggests that its phase behavior in solution is entropy driven. Salt effects on cloud points follow the well-known Hofmeister series. Anions leading to increased structuring of water lower the cloud point, as does the substitution of D2O for H2O. The cloud point data correlate linearly with the change in water entropy upon the addition of electrolytes.

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Section: Introductionmentioning

confidence: 99%

A Neutron Scattering Study of Poly(ethylene glycol) in Electrolyte Solutions

Thiyagarajan¹,

Chaiko²,

Hjelm³

1995

Macromolecules

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“…Consequently, particle size should be small enough that particle settling due to gravity is low compared to the rate of 1iquidAiquid phase separation. In general, we have found that an upper size limit of about 150-200 ym can be accommodated during continuous, countercurrent extractions (6,7).…”

Section: Introductionmentioning

confidence: 90%

“…We have been evaluating various types of ABE systems for possible applications in the treatment of solid radioactive wastes (1,2), liquid nuclear wastes (3,4), and contaminated soils (5)(6)(7), and in the removal of organics from aqueous salt solutions (8). We have also conducted fundamental studies of the solution microstructure of ABE systems using small angle neutron scattering (SANS) (9).…”

Section: Introductionmentioning

confidence: 99%

Metal separations using aqueous biphasic partitioning systems

Chaiko¹,

Zaslavsky²,

Rollins³

et al. 1996

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Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that we have studied are generated by combining an aqueous salt solution with an aqueous polymer solution.We have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. We have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). h this chapter we review the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation.

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Aqueous biphasic extraction of uranium and thorium from contaminated soils. Final report

Abstract: Portions of this document mag be illegible ' in electronic image products. m e s are produced from the best available original dOCUIIlent.

Cited by 2 publications

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A Neutron Scattering Study of Poly(ethylene glycol) in Electrolyte Solutions

A Neutron Scattering Study of Poly(ethylene glycol) in Electrolyte Solutions

Metal separations using aqueous biphasic partitioning systems

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