Extraction of Am(III) in the presence of lanthanides and yttrium by benzyldimethyldodecylammonium nitrate from acidic nitrate solutions

We have investigated the effect of coextraction of lanthanides and yttrium on the distribution coefficients D_Am in the extraction of americium by benzyldimethyldodecylammonium nitrate (BDMLNNO₃) from nitrate solutions. In the coextraction of lanthanides, the extraction of Am(NO₃)₃ is suppressed, which is markedly manifested in the extraction of light lanthanides (La, Ce, Pr); of the series of lanthanides their extraction is the highest. The effect of nitric acid and the possibility of separation of lanthanides and americium by the application of three-stage multiple extraction is discussed.     

Extraction of ruthenium(III) by dihexyl sulfoxide from hydrochloric solutions

The extraction of ruthenium(III) by dihexyl sulfoxide (DHSO) from hydrochloric solutions is studied. Ruthenium(III) is first extracted by a hydration/solvation mechanism followed by the incorporation of extractant molecules into the inner coordination sphere of the ruthenium(III) ion. The composition of the extracted compound is suggested proceeding from the resuls of electronic, ¹H NMR spectroscopy, IR spectroscopy, and elemental analysis.     

Separation of americium(III) from lanthanides(III) by nanofiltration-complexation in aqueous medium

The separation of Am(III) from a mixture of lanthanides(III) was performed in aqueous medium by nanofiltration combined with a complexation step using a DTPA derivative as selective complexing agent.     

Structural study of lanthanides(III) in aqueous nitrate and chloride solutions by EXAFS

Structural studies of lanthanide ions (Nd³⁺≈Lu³⁺: about 1 mol/l) in the aqueous chloride (HCl: 0≈6 mol/l) and nitrate (HNO₃: 0?13 mol/l) solutions were carried out by extended X-ray absorption fine structure (EXAFS). The radial structural functions appeared to be mainly characterized by hydration in both chloride and nitrate systems and coordination of nitrate ion in nitrate systems. These results indicated that nitrate ion forms inner-sphere complex with lanthanide but chloride ion hardly forms one. The quantitative analyses of EXAFS data have revealed that the total coordination numbers of lanthanide ranged from about 9 for light lanthanides to about 8 for heavy lanthanides in all the samples. The bond distances of Ln?O were from about 2.3 to 2.5 Å for Ln?OH₂ and from about 2.4 to 2.6 Å for Ln?O₂NO. Nitrate ion locates at 0.1 Å longer position than water, it suggested that nitrate ion ligates more weakly than water.     

Adsorption of lanthanides(III) from aqueous solutions by fullerene black modified with di(2-ethylhexyl)phosphoric acid

Fullerene black (FB) - a product of electric arc graphite vaporization after extraction of fullerenes - was modified with the di(2-ethylhexyl)phosphoric acid (D2EHPA). The distribution of D2EHPA between FB and aqueous HNO₃ solutions has been studied. The effect of HNO₃ concentration in the aqueous phase and that of D2EHPA concentration in the sorbent phase on the adsorption of microquantities of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y nitrates from HNO₃ solutions by D2EHPA-modified FB are considered. The stoichiometry of the sorbed complexes has been determined by the slope analysis method. The efficiency of lanthanides’ adsorption increases with an increase in the element atomic number. A considerable synergistic effect has been observed upon the addition of the neutral bidentate tetraphenylmethylenediphosphine dioxide ligand to D2EHPA in the sorbent phase.      

Extraction of chlororuthenium(III) complexes by triazole derivatives from hydrochloric acid solutions

The extraction of ruthenium(III) by triazole derivatives from hydrochloric acid solutions has been studied. The extraction of ruthenium(III) is implemented by the ion-association mechanism. The composition of the extraction compound has been determined using electronic, ¹H NMR, ¹³C NMR, and IR spectroscopy and elemental analysis.     

Extraction of chlororuthenium(III) complexes from hydrochloric acid solutions by petroleum sulfoxides

The extraction of ruthenium(II) by petroleum sulfoxides (PSOs) from hydrochloric acid solutions has been studied. The extraction of ruthenium(III) by PSOs is implemented by the coordination mechanism with the incorporation of the sulfoxide oxygen atom of the extractant into the inner coordination sphere of the ruthenium(III) ion. The composition of the extraction compound is suggested using electronic, ¹H NMR, and IR spectroscopy, the slope method, and elemental analysis.     

Extraction of rhodium(III) with sulfoxides from hydrochloric acid solutions

Extraction of rhodium(III) from hydrochloric acid solutions with dihexyl sulfoxide (DHSO) and with petroleum sulfoxides (PSOs) was studied, and the optimal conditions for its recovery were found. At a phase contact time of up to 0.5 h, the extraction of rhodium(III) with sulfoxides occurred mainly by an ionassociation scenario. If the phase contact time exceeds 0.5 h, a mixed extraction scenario predominated to form the extracted complexes (L · H⁺) · [RhCl₄L₂]-(DHSO)_o and PSO (LH⁺) · [RhCl₄(H₂O) · L]⁻. The protonation of the extraction agents occurred at the donor oxygen atoms of the sulfoxide group. When rhodium was extracted with PSOs, the coordination of the extractant molecule in the inner coordination sphere of the acido complex to the metal ion occurred through the donor sulfur atom of the sulfoxide group, while with the use of DHSO, through the donor atoms of sulfur and oxygen of the sulfoxide group. Electronic, ¹H NMR, and IR spectroscopy and elemental analysis were used to determine the composition of the extracted compounds and suggest their structure.     

Extraction of Ce(III) with naphthenic acid from nitrate solutions

Extraction of Ce(III) with naphthenic acid from nitrate solutions was studied. The composition of solvation complexes, extraction constants, and Gibbs energies of extraction were found from the dependences of the distribution coefficients on pH and compositions of the aqueous and organic phases.     

Extraction of rhodium(III) by a bisacylated diethylenetriamine derivative from hydrochloric acid solutions

The extraction of rhodium(III) with a bisacylated diethylenetriamine derivative from hydrochloric acid solutions was studied. Optimum conditions for rhodium(III) extraction were determined. It was found that, at a contact time to 10 min, the extraction occurred by an ion-association mechanism. At a contact time longer than 10 min, rhodium(III) was extracted by a mixed mechanism with the insertion of an extractant molecule into the inner coordination sphere of the rhodium(III) ion. The composition of the extracted compound was determined using electronic, ¹H and ¹³C NMR, and IR spectroscopy and elemental analysis, and the structure of this compound was proposed.     

Extraction of indium(III) from sulfate solutions with organophosphorus acids

Extraction of indium(III) from sulfuric acid solutions with di-2-ethylhexyl hydrogen phosphate and isododecylphosphethanic and diisooctylphosphinic acids was studied. The effect of H₂SO₄ and In(III) concentrations in the aqueous phase, type and concentration of the extractant in the organic phase, temperature, and time of phase contact on the extraction of In(III) and impurity metal ions was considered. The In(III) extraction constants were estimated.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 10, 2004, pp. 1625–1629.Original Russian Text Copyright © 2004 by Travkin, Kubasov, Glubokov, Busygina, Kazanbaev, Kozlov.     

Extraction of rhodium(III) by 1,3-diamyl-2-imidazolidinethione from hydrochloric acid solutions

The extraction of rhodium(III) with 1,3-diamyl-2-imidazolidinethione from hydrochloric acid solutions was studied. Optimum conditions for rhodium(III) extraction were determined. It was found that rhodium(III) was extracted from a 0.5 M solution of HCl at a phase contact time of 3 h by a coordination mechanism. The composition of the extracted compound was determined using electronic, ¹H and ¹³C NMR, and IR spectroscopy and elemental analysis. It was demonstrated that the extracting agent coordinated to the rhodium(III) ion through the sulfur atom.     

Extraction of arsenic(III) from chloride-iodide solutions by diphenyl(2-pyridyl)methane and benzene

The variation of the partition coefficient of arsenic(III) between chloride-iodide solutions and diphenyl(2-pyridyl)methane in benzene has been studied. The effect of the concentration of hydrochloric acid and iodide in the aqueous phase has been assessed. The partition coefficients are maximal for concentrated acid solutions which are 0.02-0.1 M in potassium iodide. Slope-analysis studies were used to elucidate the composition of the extracted species. Polymerization of the solvent species tends to decrease the distribution coefficients of arsenic with increasing concentration of diphenyl(2-pyridyl)methane, especially with trace concentrations of the element. Arsenic can be selectively separated from copper, cobalt, nickel, iron, chromium and antimony, which are usually associated with it in various ores.     

Oxoselenido clusters of the lanthanides: rational introduction of oxo ligands and near-IR emission from Nd(III)

Reactions of Ln(SePh)3 with SeO2 in THF give octanuclear oxoselenido clusters with the general formula (THF)8Ln8O2Se2(SePh)16 (Ln = Ce, Pr, Nd, Sm). In this isomorphous series, the eight Ln(III) ions are connected in the center by a pair of mu3-O2- ligands and mu5-Se2- ligands, with 14 bridging and two terminal selenolate ligands capping the cluster surface. Thermal decomposition at 700 degrees C of the Nd compound in vacuo led to the formation of a phase mixture of NdSe2, Nd2Se3, and Nd2O3. Near-IR emission experiments on the (THF)8Nd8O2Se2(SePh)16 and the fluorinated thiolate compound (DME)2Nd(SC6F5)3 demonstrate that clusters with oxo ligands are not only highly emissive, but also they emit at wavelengths not found in conventional oxides.     

Extraction of rhenium(VII) by phosphorylated podands

The interphase distribution of ReO ₄ ^- between aqueous H₂SO₄ solutions and solutions of phosphorylated podands in organic solvents is studied. The stoichiometry of extracted complexes is determined. The rhenium extraction efficiency is considered as a function of the structure of the extractant and the nature of the organic solvent.     

Extraction of rhodium(III) with petroleum sulfoxides from hydrochloric acid solutions

Extraction of rhodium(III) from hydrochloric acid solutions with petroleum sulfoxides was studied. The optimal conditions of its recovery were found. The composition and structure of the compound being extracted was determined by electronic absorption, ¹H NMR, and IR spectroscopies and elemental analysis.     

Solvent Extraction Separation of Iridium(III) from Rhodium(III) by N-n-Octylaniline

The use ofN-n-octylaniline for the extraction of iridium(III) from malonate media is studied at pH 8.5. Iridium(III) extracted in the organic phase was stripped with 2.0 M hydrochloric acid and was determined spectrophotometrically by the stannous chloride–hydrobromic acid method at 385 nm. The extraction system is studied as a function of the equilibration time, diluent, reagent concentration and diverse ions. Experimental data have been analyzed graphically to determine the stoichiometry of the extracted species. It was found that the extraction of iridium(III) proceeds by an anion exchange mechanism and transforms into the extracted species [RR"NH₂ ⁺Ir(C₃H₂O₄)₂ ^–]_org. The method is simple, rapid, and selective and has been devised for the sequential separation of iridium(III) from rhodium(III), not only from each other, but also from other accompanying Platinum Group Metals (PGMs), Au(III), and base metals.     

Extraction of trivalent actinides and lanthanides by tertiary and quaternary amines from concentrated chloride solutions

Extraction of some trivalent actinides and lanthanides from 11.9 M LiCl (pH 2.0) by some primary, secondary, tertiary and quaternary amines in xylene has been studied. Negligible extraction of the metal ions was found with primary and secondary amines whereas they are appreciably extracted with tertiary and quaternary amines, the trivalent actinides always being extracted to a greater extent. The separation factors Kd An(III)/Kd Ln(III) for several trivalent actinides with respect to Eu(III) and Tm(III) are found to be much greater when tertiary amines are used as extractants compared to when quaternary amines are used which has been ascribed to the extraction of higher chloro complexes of the metal ions by tertiary amines. Absorption spectra of Am(III) and Nd(III) extracted into the long chain amines from 11.0 M LiCl (pH 2.0) indicate that octahedral hexachloro complexes are present in the tertiary amine extracts whereas lower complexes are predominantly extracted by the quaternary amines leading to the observed lower separation factors for the trivalent actinides with reference to the lanthanides. Possible role of hydrogen bonding in the stabilization of chloro complexes extracted by tertiary amines as well as the extraction of hydrated chloro complexes by the quaternary amines are discussed.     

Extraction kinetics of iron(III) from aqueous nitrate solutions to toluene solutions of tri-n-butylacetohydroxamic acid

The forward and reverse extraction rate of Fe³⁺ at time zero between aqueous nitrate solutions and toluene solutions of tri-n-butylacetohydroxamic acid, HX, has been studied as function of the composition of the system and the stirring speed of the two phases. Experimental information has been also obtained on the degree of aggregation of HX, its surface active properties, its solubility in the aqueous phase as well as on the equilibrium distribution of Fe(III). Rate equations have been derived. The rate determining step of the extraction reaction has been shown to be the reaction of the free and hydrolyzed iron ions, Fe³⁺ (hydrated) and FeOH⁺ (hydrated), with the HX undissociated molecules. The reactions occur simultaneously in the aqueous phase (homogeneous path) and at the interface (heterogeneous path). A correlation between the rate constants and the equilibrium constant of the extraction reaction of Fe(III) has been established.