N,N-Dialkyl amides as extractants for spent fuel reprocessing: an overview

Pathak, P. N.

doi:10.1007/s10967-014-2961-0

Cited by 58 publications

(19 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[32] All D U values are identical at 1 M HNO 3 , which we assume to be merely a coincidence. On the other hand, above 2 M HNO 3 , the D U values followed the trend [C 4…”

Section: Evaluation Of Dhoa In Different Ionic Liquids For U(vi) Extrmentioning

confidence: 99%

See 1 more Smart Citation

Extraction of uranium(VI) from nitric acid solutions using N,N-dihexyloctanamide in ionic liquids: Solvent extraction and spectroscopic studies

Prabhu

Mohapatra

Raut

et al. 2017

Solvent Extraction and Ion Exchange

View full text Add to dashboard Cite

Liquid-liquid extraction studies of uranium(VI) were carried out from nitric acid medium using di-n-hexyloctanamide (DHOA) in several room-temperature ionic liquids (RTIL). The extraction of the metal ion as a function of nitric acid concentration showed different trends based on the alkyl substituents of the RTIL. While the D U values decreased with increasing HNO 3 concentration with [C 4 mim][NTf 2 ] and [C 6 mim][NTf 2 ], an opposite trend was seen with [C 8 mim][NTf 2 ]. This suggested that while a cation-exchange mechanism is operative with the former diluents, an ion-pair mechanism is prevalent for the latter. The extracted species were found to contain about 3 and 2 molecules of DHOA from the feed solution containing 0.01 M and 4 M HNO 3 , respectively, which was arrived at from the ligand-concentration-variation experiments. Recycling studies were also performed by carrying out stripping and radiolytic stability studies. The nature of the extracted species as ascertained from the UV-visible spectrophotometry studies indicated similarity between the extracts obtained in RTIL medium, which were entirely different from that observed with n-dodecane as the diluent.---

show abstract

“…[32] All D U values are identical at 1 M HNO 3 , which we assume to be merely a coincidence. On the other hand, above 2 M HNO 3 , the D U values followed the trend [C 4…”

Section: Evaluation Of Dhoa In Different Ionic Liquids For U(vi) Extrmentioning

confidence: 99%

“…[2,3] Among the dialkyl amides, di-n-hexyl octanamide (DHOA, Fig. 1) has been found to be particularly interesting due to its favorable extraction properties visà-vis TBP and several recent countercurrent extraction studies underline its potential [4][5][6] .…”

Section: Introductionmentioning

confidence: 99%

Extraction of uranium(VI) from nitric acid solutions using N,N-dihexyloctanamide in ionic liquids: Solvent extraction and spectroscopic studies

Prabhu

Mohapatra

Raut

et al. 2017

Solvent Extraction and Ion Exchange

View full text Add to dashboard Cite

show abstract

“…Their degradation products are relatively innocuous to the solution chemistry (mainly carboxylic acids and secondary amines [15]) which, if small enough, may even leave the reprocessing flowsheet in the aqueous raffinate rather than remain in the organic phase to be removed. After many studies, N,N-dihexyloctanamide (DHOA) has been presented as one of the best potential TBP replacements [16][17][18][19]. It boasts excellent Pu recovery; however, U recovery is less efficient than with TBP [17].…”

Section: Introductionmentioning

confidence: 99%

Spectrophotometric Analysis of Ternary Uranyl Systems to Replace Tri-N-butyl Phosphate (TBP) in Used Fuel Reprocessing

et al. 2020

View full text Add to dashboard Cite

In this report, the interaction of monoamide/diamide and monoamide/diglycolamide mixtures with UO 2+ 2 are investigated in pH = 1 methanolic nitric acid media. These monoamides include N,N-dimethylacetamide (DMAA), N,N-diethylacetamide (DEAA), N,N-dibutylacetamide (DBAA) and N,N-dibutylbutanamide (DBBA). N,N,N′N′tetraethylmalonamide (TEMA) and N,N,N′,N′-tetraethyldiglycolamide (TEDGA), which were chosen as model diamides and diglycolamides, respectively. Complex stability constants for each ligand were modelled using the Stability Quotients Using Absorbance Data program using UV-visible data. Complex stoichiometry of ligand mixtures was determined using Job plots and UV-Vis spectrometry. Monoamides were confirmed to produce only disolvate complexes with UO 2+ 2 in solution. The log 10 (K) values for monoamides were found to be independent of amine-side chain length, but were slightly dependent on the carbonyl-side chain length. TEDGA was found to produce multiple uranyl complexes in solution. Job plot data indicated that the uranyl cation strongly prefers to bond either only with the monoamide or diamide in ternary monoamide-diamide-UO 2 systems. Monoamide-diglycolamide-UO 2 systems were more complicated, with Job plot data indicating the potential for multiple ternary species being present is dependent on the monoamide structure.

show abstract

“…Even if the processes using Tributyl phosphate (TBP) as selective extractant are known since world-war II, economic and technical reasons motivate the research for alternative extractants. One promising approach that is under development since several years is the use of N,N-dialkylamides which also have a high affinity towards Uranium and Plutonium and significant advantages over TBP [8][9][10][11]. The main disadvantage of N,Ndialkylamides is the viscosity of the organic phase which increases exponentially when processes are intensified by increasing uranyl and extractant concentration [12].…”

Section: Introductionmentioning

confidence: 99%

“…The extraction and coordination of major actinides by N,N-dialkylamides has been intensively studied in the last decades [10,[17][18][19][20][21]. Ferru and co-workers have been the first to investigate the aggregation behavior at molecular and supramolecular scale at elevated extractant concentration by combining molecular dynamics and X-ray scattering [6,22,23].…”

Section: Introductionmentioning

confidence: 99%

A minimal predictive model for better formulations of solvent phases with low viscosity

Pleines

Hahn

Duhamet

et al. 2020

EPJ Nuclear Sci. Technol.

View full text Add to dashboard Cite

The viscosity increase of the organic phase when liquid–liquid extraction processes are intensified causes difficulties for hydrometallurgical processes on industrial scale. In this work, we have analyzed this problem for the example of N,N-dialkylamides in the presence of uranyl nitrate experimentally. Furthermore, we present a minimal model at nanoscale that allows rationalizing the experimental phenomena by connecting the molecular, mesoscopic and macroscopic scale and that allows predicting qualitative trends in viscosity. This model opens broad possibilities in optimizing constraints and is a further step towards knowledge-based formulation of extracting microemulsions formed by microstructures with low connectivity, even at high load with heavy metals.

show abstract

N,N-Dialkyl amides as extractants for spent fuel reprocessing: an overview

Cited by 58 publications

References 35 publications

Extraction of uranium(VI) from nitric acid solutions using N,N-dihexyloctanamide in ionic liquids: Solvent extraction and spectroscopic studies

Extraction of uranium(VI) from nitric acid solutions using N,N-dihexyloctanamide in ionic liquids: Solvent extraction and spectroscopic studies

Spectrophotometric Analysis of Ternary Uranyl Systems to Replace Tri-N-butyl Phosphate (TBP) in Used Fuel Reprocessing

A minimal predictive model for better formulations of solvent phases with low viscosity

Contact Info

Product

Resources

About