Extraction of REE(III), U(VI), and Th(IV) from Nitric Acid Solutions with Carbamoylmethylphosphine Oxides in the Presence of Bis[(trifluoromethyl)sulfonyl]imide Ions

Extraction of microamounts of REE(III), U(VI), and Th(IV) with solutions of carbamoylmethylphosphine oxides (CMPOs) in organic diluents from aqueous HNO₃ solutions containing lithium bis[(trifluoromethyl) sulfonyl]imide (LiTf₂N) was studied. The efficiency of the REE(III), U(VI), and Th(IV) extraction from nitric acid solutions with CMPO solutions considerably increases in the presence of Tf₂N^– ions in the aqueous phase. The stoichiometry of the extractable complexes was determined, and the influence of the structure of the CMPO molecule, kind of organic diluent, and aqueous phase composition on the efficiency of the U(VI), Th(IV), and REE(III) extraction into the organic phase was considered.     

Extraction of U(VI), Th(IV), and REE(III) from nitrate solutions with diaryl(dialkylcarbamoylalkyl)phosphine oxides containing a dialkylcarbamoylmethyl substituent in the alkylene bridge

The extraction of microamounts of U(VI), Th(IV), and REE(III) from HNO₃ and NH₄NO₃ solutions with solutions of diaryl(dialkylcarbamoylalkyl)phosphine oxides containing a dialkylcarbamoylmethyl substituent in the alkylene bridge was studied. The stoichiometry of the complexes extracted from nitric acid solutions with N,N,N',N'-tetrabutyl-2-(di-p-anisylphosphinyl)butanedioic diamide I was determined. The influence of the extractant structure and aqueous phase composition on the efficiency and selectivity of the extraction of U(VI), Th(IV), and REE(III) into the organic phase was examined. Introduction of the–CH₂C(O)NAlk₂ fragment into the methylene bridge of the diaryl(dialkylcarbamoylmethyl)phosphine oxide molecule considerably enhances the extraction of REE(III) from neutral nitrate solutions. Such modification of the extractant molecule only slightly influences the extraction of REE(III) from nitric acid solutions, but leads to a considerable increase in the U(VI) extraction and to a decrease in the Th(IV) extraction. The selectivity of the extraction of U(VI) and REE(III) is thus considerably increased.     

Effect of Fe(III) on the extraction of U(VI), Th(IV), and REE(III) from HCl solutions with diphenyl(dibutylcarbamoylmethyl)phosphine oxide

The extraction of U(VI), Th(IV), and REE(III) from HCl solutions with solutions of diphenyl(dibutylcarbamoylmethyl)phosphine oxide in dichloroethane in the presence of Fe(III) was studied. An increase in the Fe concentration in the organic phase leads to a considerable increase in the distribution ratios of U(VI), Th(IV), and REE(III), which is caused by transfer into the organic phase of mixed complexes MCl _m?n (FeCl₄) _n solvated by the extractant molecules. A macroporous styrene-divinylbenzene copolymer impregnated with diphenyl(dibutylcarbamoylmethyl)phosphine oxide can be used for concentrating U(VI), Th(IV), and REE(III) from HCl solutions in the presence of Fe(III).     

Extraction and sorption preconcentration of U(VI), Th(IV), and REE(III) from nitric acid solutions using bis[2-(diphenylphosphinyl)phenoxymethyl]phosphinic acid

Extraction of microamounts of U(VI) and Th(IV) from HNO₃ solutions in the form of complexes with polyfunctional organophosphorus acids was studied. The influence of the extractant structure on the efficiency and selectivity of the extraction of U(VI) and Th(IV) was examined, and the stoichiometry of the extractable complexes was determined. The possibility of preconcentration of U(VI), Th(IV), and REE(III) from nitric acid solutions with a complexing sorbent prepared by noncovalent immobilization of bis[2-(diphenylphosphinyl) phenoxymethyl]phosphinic acid on a macroporous polymeric matrix was demonstrated.     

Extraction of REEs(III), U(VI), and Th(IV) with acidic phosphoryl-containing podands from nitric acid solutions

The extraction of microamounts of REEs(III), U(VI), and Th(IV) from HNO₃ solutions with solutions of acidic phosphoryl-containing podands in 1,2-dichloroethane was studied. The stoichiometry of the extractable complexes was determined. The influence of the extractant structure and aqueous phase composition on the efficiency and selectivity of the recovery of REEs(III), U(VI), and Th(IV) into the organic phase was considered.     

1,3-Bis[(diphenylphosphorylacetamido)methyl]benzene as reagent for extraction and sorption preconcentration of REE(III), U(VI), and Th(IV) from nitric acid solutions

The extraction of microamounts of REE(III), U(VI), and Th(IV) from HNO₃ solutions in the form of complexes with a polyfunctional neutral organophosphorus compound, 1,3-bis[(diphenylphosphorylacetamido)-methyl]benzene, was studied. The influence exerted by the structure of the bridge binding two carbamoylmethyl-phosphine oxide fragments on the efficiency of the extraction of REE(III), U(VI), and Th(IV) and on the stoichiometry of the extractable complexes was analyzed. The possibility of recovering and concentrating REE(III), U(VI), and Th(IV) from nitric acid solutions with a complexing sorbent prepared by noncovalent immobilization of 1,3-bis[(diphenylphosphorylacetamido)methyl]benzene on the surface of carbon nanotubes was examined.     

Extraction of U(VI), Th(IV), and REE(III) from Nitric Acid Solutions with 2,6-Bis(diphenylphosphorylmethyl)pyridine <Emphasis Type="Italic">N</Emphasis>-Oxide

The extraction of microamounts of U(VI), Th(IV), and REE(III) from HNO₃ solutions in the form of complexes with 2,6-bis(diphenylphosphorylmethyl)pyridine N-oxide (I) was studied in relation to the kind of organic diluent and to the HNO₃ concentration in the equilibrium aqueous phase. The stoichiometry of the extractable complexes was determined. With respect to the ability to extract Th(IV) and REE(III), compound I considerably surpasses tetraphenylmethylenediphosphine dioxide and tetraalkyl-substituted analogs of I.     

Extraction and sorption preconcentration of U(VI), Th(IV), and REE(III) from nitric acid solutions using amine-substituted tetraarylethylenediphosphine dioxides

Extraction of U(VI), Th(IV), and REE(III) from HNO₃ solutions in the form of complexes with amine-substituted tetraarylethylenediphosphine dioxides was studied. The effect of substituents at the P atoms in the extractant molecule on its extraction ability was examined. The stoichiometry of the extractable complexes was determined. The possibility of preconcentration of U(VI), Th(IV), and REE(III) with the complexing sorbent prepared by noncovalent immobilization of the examined extractants on a polymer matrix was demonstrated.     

Preconcentration of U(VI), Th(IV), and REE(III) from nitric acid solutions using carbon nanotubes modified with bis(dioctylphosphinylmethyl)phosphinic acid

The extraction of microamounts of U(VI) and Th(IV) from HNO₃ solutions in the form of complexes with bis(dioctylphosphinylmethyl)phenylphosphinic acid was studied. The stoichiometry of the extractable complexes was studied, and the influence of the extractant structure on the efficiency and selectivity of the U(VI) and Th(IV) extraction was examined. U(VI), Th(IV), and REE(III) can be preconcentrated from nitric acid solutions with a complexing sorbent prepared by noncovalent immobilization of bis(dioctylphosphinylmethyl) phosphinic acid on the surface of carbon nanotubes.     

Extraction of REE(III), U(VI), and Th(IV) from HNO<Subscript>3</Subscript> and HClO<Subscript>4</Subscript> solutions with (α-pyridyl)tetraphenylmethylenediphosphine <Emphasis Type="Italic">N,P,P</Emphasis>'-trioxide

Extraction of microamounts of U(VI), Th(IV), and REE(III) from HNO₃ and HClO₄ solutions with solutions of (α-pyridyl)tetraphenylmethylenediphosphine N,P,P'-trioxide in dichloroethane was studied. The stoichiometry of the extractable complexes was determined, and the influence of the extraction structure and aqueous phase composition on the efficiency and selectivity of the extraction of U(VI), Th(IV), and REE(III) into the organic phase was studied. Introduction of the pyridine N-oxide fragment into the methylene bridge of the tetraphenylmethylenediphosphine dioxide molecule to obtain (α-pyridyl)tetraphenylmethylenediphosphine N,P,P'-trioxide leads to a decrease in its ability to extract U(VI), Th(IV), and REE(III) from nitric acid solutions, whereas the U/REE separation factors increase. The REE(III) extraction efficiency considerably increases in going from nitric acid to perchloric acid solutions.     

Extraction Properties of Butyl Bis(dibutoxyphosphinylmethyl)phosphinate in Nitric Acid Solutions

The extraction of HNO₃ and microamounts of U(VI), Th(IV), Sc(III), REE(III), and Am(III) nitrates from HNO₃ solutions with solutions of butyl bis(dibutoxyphosphinylmethyl)phosphinate in organic diluents was studied. The stoichiometry of the extractable complexes was determined, and the apparent extraction constants were calculated. The capability of the extractant to recover the examined elements from nitric acid solutions grows with an increase in the number of phosphoryl groups in its molecule. The recovery of the metal ions into the organic phase becomes more efficient in going to more polar organic diluents.     

Selectivity of extraction of U(VI), Th(IV), and REE(III) from perchloric acid solutions with bidentate phosphoryl-substituted butyl phenylphosphinates

Extraction of microamounts of U(VI), Th(IV), and REE(III) from HClO₄ solutions with solutions of bidentate phosphoryl-substituted butyl phenylphosphinates R₂P(O)CH₂P(O)Ph(OBu) [R = phenyl (I), octyl (II)] in dichloroethane was studied. The effect of substituents at the phosphorus atom in the phosphine oxide moiety of these compounds on their extraction ability and selectivity was examined, and the stoichiometry of the extractable complexes was determined. In going from nitric to perchloric acid solutions, the efficiency of the extraction of U(VI) and REE(III) considerably increases, the U/REE separation factors increase, but the Th/U separation factors decrease.     

Extraction of U(VI), Th(IV), Pu(IV), and Am(III) from nitric acid solutions with polyfunctional organophosphorus acids

Extraction of microamounts of U(VI), Th(IV), Pu(IV), and Am(III) nitrates from aqueous HNO₃ solutions with solutions of (diphenylphosphinylmethyl)phenylphosphinic, (di-p-tolylphosphinylmethyl)phenylphosphinic, and (dioctylphosphinylmethyl)phosphinic acids and of butyl hydrogen (diphenylphosphinylmethyl)phosphonate in organic diluents was studied. The metal: extractant stoichiometric ratio in the extractable complexes was determined, and the diluent effect on the extraction efficiency was examined. The possibility of using a macroporous polymeric sorbent impregnated with (dioctylphosphinylmethyl)phenylphosphinic acid for concentrating metal ions from HNO₃ solutions was demonstrated.     

Extraction of U(VI), Th(IV), and rare-earth elements from nitric acid solutions with phosphoryl-and carbonyl-containing podands

The distribution of HNO₃ and microamounts of nitrates of U(VI), Th(IV), La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y between aqueous solutions of HNO₃ and solutions of N,N′-dimethyl-N,N′-diphenyl-3-oxapentanediamide (I) and 1,3-bis(diphenylphosphinoyl)-2-oxapropane (II) in organic diluents was studied. The stoichiometry of the extractable complexes was determined, and the effect exerted by the extractant structure and by the organic diluent on the efficiency of recovery of rare-earth elements (REE) into the organic phase was examined. In nitric acid solutions, carbonyl-containing podand I surpasses in the extraction ability phosphoryl-containing podand II. The possibility of using a macroporous polymeric sorbent impregnated with compound I for recovering REE from nitric acid solutions was demonstrated. Original Russian Text A.N. Turanov, V.K. Karandashev, V.E. Baulin, 2007, published in Radiokhimiya, 2007, Vol. 49, No. 3, pp. 226–232.     

Extraction of REE(III), U(VI), and Th(IV) from Nitric Acid Solutions with Carbamoylmethylphosphine Oxides in the Presence of Dinonylnaphthalenesulfonic Acid

The extraction of REE(III), U(VI), and Th(IV) from nitric acid solutions with solutions of carbamoylmethylphosphine oxides (CMPOs) considerably increases in the presence of dinonylnaphthalenesulfonic acid. The stoichiometry of the extractable complexes was determined, and the influence of the aqueous phase composition, kind of organic diluent, and CMPO structure on the efficiency of the extraction of the metal ions was analyzed.     

Extraction of REE(III), U(VI), and Th(IV) from Perchlorate Solutions with Tetraphenyl(o-oxyphenylenemethylene)diphosphine Dioxide

Radiochemistry - The extraction of microamounts of REE(III), U(VI), and Th(IV) from perchlorate solutions with solutions of tetraphenyl(o-oxyphenylenemethylene)diphosphine dioxide (I) in...     

Extraction and sorption preconcentration of U(VI) and Th(IV) from nitric acid solutions using bis(diphenylphosphorylmethylcarbonylamino)alkanes

Extraction of microamounts of U(VI) and Th(IV) from HNO₃ solutions in the form of complexes with polyfunctional neutral organophosphorus compounds, bis(diphenylphosphorylmethylcarbonylamino)alkanes [Ph₂P(O)CH₂C(O)NH]₂(CH₂) _n (n = 3, 5, 8), was studied. The influence of the extractant structure on the efficiency and selectivity of the extraction of U(VI) and Th(IV) was examined, and the stoichiometry of the extractable complexes was determined. The examined compounds exhibit higher extraction ability and selectivity to metal ions in HNO₃ solutions, compared to the alkylamide Ph₂P(O)CH₂C(O)NHC₉H₁₉. The possibility of selective recovery and preconcentration of U(VI) and Th(IV) from nitric acid solutions with a complexing sorbent prepared by noncovalent immobilization of bis(diphenylphosphorylmethylcarbonylamino)pentane on a macroporous polymeric matrix was demonstrated.     

Extraction of REE(III), U(VI), and Th(IV) from Perchloric Acid Solutions with 2,6-Bis(diphenylphosphorylmethyl)pyridine N-Oxide

Radiochemistry - The extraction of microamounts of REE(III), U(VI), and Th(IV) from HClO4 solutions with solutions of 2,6-bis(diphenylphosphorylmethyl) pyridine N-oxide (I) in 1,2-dichloroethane...     

Extraction of REE(III), U(VI), and Th(IV) from Nitric Acid Solutions with Diphenyl(dibutylcarbamoylmethyl)phosphine Oxide in the Presence of Quaternary Ammonium Bis[(trifluoromethyl)sulfonyl]imides

Radiochemistry - The extraction of REE(III), U(VI), and Th(IV) from nitric acid solutions with solutions of diphenyl(dibutylcarbamoylmethyl)phosphine oxide considerably increases in the presence of...     

Extraction of rare-earth elements from nitric acid solutions with bidentate neutral organophosphorus compounds in the presence of l-butyl-3-methylimidazolium hexafluorophosphate

The distribution of microamounts of La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y nitrates between aqueous HNO₃ solutions and solutions of tetraphenylmethylenediphosphine dioxide, diphenyl(diethylcarbamoylmethyl)phosphine oxide, and dibutyl(diethylcarbamoylmethyl)phosphine oxide in organic solvents in the presence of l-butyl-3-methylimidazolium hexafluorophosphate (BMImPF₆) was studied. The stoichiometry of the extractable complexes was determined. The influence of the HNO₃ concentration and the nature of the extractant and organic solvent on the synergistic effect observed in the REE extraction in the presence of BMImPF₆ in the organic phase was analyzed. The possibility of using a macroporous polymeric sorbent impregnated with a mixture of tetraphenylmethylenediphosphine dioxide and BMImPF₆ for the recovery of REE(III), U(VI), and Th(IV) from HNO₃ solution was demonstrated.