Separation of La(III), Eu(III), and Ho(III) with Sorbents Impregnated by Mixtures of Acidic Phosphoryl Podands and Amines in Nitric Acid Solutions

ABSTRACT

The possibility of separation of La(III), Eu(III), and Ho(III) as respective individual representatives of light, medium, and heavy rare earth elements was studied using sorbents impregnated by mixtures of acidic phosphoryl podands derived from diethylene glycol and octyl, dioctyl, and trioctyl amines from nitric acid solutions of various concentrations. The influence of the phosphoryl podands structure, their percentage content, and proportion in a sorbent and the nature of an acid on the efficiency of separation of La(III), Eu(III), Ho(III) was studied. It is shown that the greater is the concentration of HNO₃, the smaller are the separation factors of REEs, and remarkably so. The most efficient separation is achieved with the concentration of HNO₃ not over 0.04 mol/L. The optimal conditions of separation of La(III), Eu(III), and Ho(III) with the developed sorbent were found. Repeated use of the sorbent for the separation of La(III), Eu(III), and Ho(III) after its regeneration with 0.04 mol/L HNO₃ was estimated. It was found that the efficiency of separation of REEs with the sorbents impregnated by a mixture of 1,5-bis(2-oxyethoxyphosphoryl-4-ethylphenoxy)-3-oxapentane and trioctylamine (TOA) exceeds markedly that made of a mixture of di-(2-ethylhexyl)phosphoric acid (DEHPA) and TOA.     

Effect of Anions on the Extraction of Lanthanides (III) by N,N′‐Dimethyl‐N,N′‐Diphenyl‐3‐Oxapentanediamide

Abstract

The extraction of microquantities of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y by N,N′‐dimethyl‐N,N′‐diphenyl‐3‐oxapentanediamide (DMDPhOPDA) in 1,2‐dichloroethane from aqueous media containing ClO₄ ^?, PF₆ ^?, (CF₃SO₂)₂N^? anions or by DMDPhOPDA in 1,2‐dichloroethane in the presence of 1‐butyl‐3‐methylimidazolium bis[(trifluoremethyl)sulfonyl]imide ([C₄mim][Tf₂N]) and 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([C₄mim][PF₆]) from HNO₃ solutions has been studied. The effect of HNO₃ concentration in the aqueous phase and that of the extractant concentration in the organic phase on the extraction of metal ions is considered. The stoichiometry of the extracted complexes has been determined. The addition of HPF₆ and (CF₃SO₂)₂NH or their salts to the aqueous HNO₃ or HCl solutions leads to an enchancement of lanthanides (III) extraction by DMDPhOPDA. A considerable synergistic effect was observed in the presence of ionic liquids (IL) in the organic phase containing DMDPhOPDA. This effect is connected with the hydrophobic nature of the IL anion. The distribution of ILs between the equilibrium organic and aqueous phases can govern the extractability of lanthanides (III) in DMDPhOPDA‐IL systems.     

Extraction of Am and Rare-Earth Elements from Nitric Acid Solutions with Ethyl Bis(diphenylphosphinylmethyl)phosphinate

Extraction of HNO₃ and microamounts of Am, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y from HNO₃ solutions with solutions of ethyl bis(diphenylphosphinylmethyl)phosphinate in dichloroethane was studied. The stoichiometry of the extractable complexes was determined, and the effective extraction constants of HNO₃ and Am were calculated. With increasing number of phosphoryl groups in the extractant molecule, the extraction of Am(III) and rare-earth elements from HNO₃ solutions increases.     

Experimental Investigation of the Penetration of Solids into a Target of Organic Glass under Impact at Velocities from 0.7 to 2.1 km/s

The results are given of experimental investigations of the interaction between spherical metal impactors and a target of organic glass. The impact velocities range from 0.7 to 2.1 km/s. Singular features of the pattern of penetration of impactors into the target are revealed. The empirical dependence of the depth of penetration on the impact energy is obtained, and comparison is made with the known formulas for superdeep penetration. An expression is derived for the limiting velocity, above which no formation of channels in the target occurs, but the impactor is completely destroyed and a crater is formed.     

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 of Lanthanides(III) from Aqueous Nitrate Media with Tetra‐(p‐tolyl)[(o‐Phenylene)Oxymethylene] Diphosphine Dioxide

A novel tridentate neutral organophosphorus compound, tetra‐(p‐tolyl)[(o‐phenylene)oxymethylene] diphosphine dioxide (I) has been synthesized and its extracting ability for microquantities of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y from HNO₃ and NH₄NO₃ aqueous solutions has been studied. The effect of HNO₃ concentration in the aqueous phase and that of the extractant concentration in the organic phase on the extraction of metal ions is considered. The stoichiometry of the extracted complexes and conditional extraction constants of Ln(III) have been determined. The extraction behavior of compound I is compared with that of the diglycolamide ligand TODGA. The potentialities of polymeric resin impregnated with compound I for the preconcentration of lanthanides(III) from nitric acid solutions are demonstrated.     

Synthesis and studies of mesomorphism of new octa-(benzo-15-crown-5)-substituted phthalocyanines and transition metal phthalocyaninates

Previously unknown octa-(benzo-15crown-5)-substituted phthalocyanine (1) and its metallocomplexes with Ni(II) (2), Co(II) (3), Cu(II) (4), Zn(II) (5), and Cd(II) (6) are synthesized. The possible formation of mesophases of these compounds is predicted and their mesomorphic properties are studied. It is found that compounds 1, 2, and 4 exhibit high-temperature enantiotropic mesomorphism typical of discotic mesogenes, which is well consistent with the predicted results. Free phthalocyanine (1) reveals dimesomorphism according to the DSC and thermomicroscopic data. According to the studies of miscibility of compound 1 with discotic mesogene, 2,3,6,7,10,11-hexa(cyclohexanebenzoyloxy)triphenylene, which exhibits nematic mesomorphism. The second phase transition is identified as the transition to a nematic phase. According to the texture of this mixture, compound 1 was classified with discotic mesogenes that form columnar nematics (N_Col). The first phase transition of 1 from a crystal to the mesophase was identified as columnar (Col). Phthalocyanines of cobalt (3) and copper(4) revealed latent mesomorphism according to the studies of their mixtures with the chiral nematic liquid crystal of cholesterin diphenylate.     

Natural Bactericidal Surfaces: Mechanical Rupture of Pseudomonas aeruginosa Cells by Cicada Wings

Natural superhydrophobic surfaces are often thought to have antibiofouling potential due to their self-cleaning properties. However, when incubated on cicada wings, Pseudomonas aeruginosa cells are not repelled; instead they are penetrated by the nanopillar arrays present on the wing surface, resulting in bacterial cell death. Cicada wings are effective antibacterial, as opposed to antibiofouling, surfaces.