A study on pyrrolidone derivatives as selective precipitant for uranyl ion in HNO3

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The solubility of UO 2 (NO 3 ) 2 (NRP) 2 (NRP = N-alkyl-2-pyrrolidone) in aqueous solutions with HNO 3 (0-5.0 M) and the corresponding NRP (0-0.50 M) has been studied. As a result, the solubility of each species of UO 2 (NO 3 ) 2 (NRP) 2 generally decreases with increasing concentrations of HNO 3 and the corresponding NRP (C HNO 3 and C NRP , respectively) in the supernatant. The solubility of UO 2 (NO 3 ) 2 (NRP) 2 also depends on the type of NRP; a higher hydrophobicity of NRP generally leads to a lower solubility of UO 2 (NO 3 ) 2 (NRP) 2 . The logarithms of effective solubility products (K eff ) of

Section: Introductionmentioning

confidence: 99%

Solubility of Uranyl Nitrate Precipitates withN-Alkyl-2-pyrrolidone Derivatives (Alkyl =n-Propyl,n-Butyl,iso-Butyl, and Cyclohexyl)

Kohara

Noda

Nogami

et al. 2009

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“…The precipitation behavior of U(VI) for EU and PU is similar to those for DMPU and NRP with formation of UO 2 (NO 3 ) 2 (DMPU) 2 and UO 2 (NO 3 ) 2 (NRP) 2 , respectively [2,3,5,7,15]. Hence, the formula of the U(VI) precipitates with L is considered to be UO 2 (NO 3 ) 2 (L) 2 .…”

Section: Precipitation Behavior Of U(vi)mentioning

confidence: 87%

“…In our previous studies [1][2][3][4], we found out that U(VI) can be precipitated selectively from HNO 3 aqueous solutions by N-alkyl-2-pyrrolidones (NRPs; see Figure 1) such as N-cyclohexyl-2-pyrrolidone (NCP), N-n-propyl-2-pyrrolidone (NProP), N-n-butyl-2-pyrrolidone (NBP), and N-neopentyl-2-pyrrolidone (NNpP). On this basis, we have proposed a new reprocessing system for spent nuclear fuels of fast breeder reactors (FBRs) [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

A study on selective precipitation of U(VI) by hydrophilic cyclic urea derivatives for development of a reprocessing system based on precipitation method

Suzuki

Kohara

Kawasaki

et al. 2014

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Selective precipitation ability of 2-imidazolidone (EU) and tetrahydro-2-pyrimidinone (PU) for U(VI) species in HNO 3 solutions containing U(VI), U(IV) (simulant of Pu(IV)), and simulated fission products (FPs) was investigated. As a result, it was found that these compounds precipitate almost quantitatively U(VI) as UO 2 (NO 3 ) 2 L 2 (L = EU, PU) from 3.0 M HNO 3 solution. In contrast, these urea derivatives form neither solid precipitates nor oily products with U(IV) in HNO 3 solutions containing only U(IV) species and even in U(VI)-U(IV) admixture system. Therefore, the separation of U(VI) from U(IV) was demonstrated to be achieved in use of EU and PU. Furthermore, EU and PU are capable to remove most of simulated FPs[Sr(II), Ru(III), Rh(III), Re(VII) La(III), Ce(III), Pr(III), Nd(III), and Sm(III)] from U(VI) to give their decontamination factors (DFs) higher than 100, while those values of Zr(IV), Mo(VI), Pd(II), and Ba(II) are necessary to be improved in both systems. From these results, it is expected that EU and PU are the promising precipitants for selective separation of U(VI) from HNO 3 solutions dissolving spent FBR fuels.

“…The obtained crystals were filtered and washed with cold ethanol and hexane, followed by air-drying. [25][26][27][28][29]32) …”

Section: Syntheses Of Uomentioning

confidence: 99%

“…Recently, it has been reported that pyrrolidone derivatives being amide compounds can selectively precipitate U(VI) in HNO 3 solutions [25][26][27][28][29] and that N-vinylpyrrolidone resin adsorbs U(VI) selectively. 30) From these viewpoints, the pyrrolidone derivatives are expected to be promising selective extractants for U(VI).…”

Section: Introductionmentioning

confidence: 99%

Extraction of Uranium(VI) from Nitric Acid Solution Using Pyrrolidone Derivatives

Takahashi¹,

Hotokezaka²,

Noda³

et al. 2009

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The extraction behavior of uranyl species from HNO 3 aqueous solutions using CH 2 Cl 2 containing pyrrolidone derivatives as extractants has been studied to find an alternative to tributyl phosphate as an extractant. In this study, we used N-cyclohexyl-2-pyrrolidone (NCP), N-octyl-2-pyrrolidone (NOP), and N-dodecyl-2-pyrrolidone (NDP) as the extractants. As a result, it was found that NCP, NOP, and NDP (abbreviated as NRP) extract U(VI) as UO 2 (NO 3 ) 2 (NRP) 2 , that a part of NCP in CH 2 Cl 2 phase is moved to the aqueous phase, and that the extractability (corresponding distribution ratio) of U(VI) increases with increasing [HNO 3 ] int from 7% (0.08) (½HNO 3 int ¼ 0:1 M, ½NRP int ¼ 1:0 M) to more than 90% (11) (½HNO 3 int ¼ 3:0 M, ½NRP int ¼ 1:0 M). From these results, it is expected that NOP and NDP extract U(VI) effectively from HNO 3 solution of more than 3 M and that the extracted U(VI) species are stripped by using HNO 3 aqueous solution of low concentration.