Extração e complexação por fase unica : estudo de quelatos metalicos de Be, AL V e Bi E complexos de associação ionica de Bi-iodeto e de Nb e Tqa com fluoreto no sistema agua-etanol - metilisobutil-cetona

AUTOR(ES)
DATA DE PUBLICAÇÃO

1991

RESUMO

The behavior of single phase liquid-liquid extraction of Be(II), Al(III), V(V), V(IV) and Bi(III) after complexation with 2-thenoyltrifluoroacetone, TTA (or 8-hydroxyquinoline for V(V) and Bi(III) has been studied in ternary mixtures of water-ethanol-isobutil methyl ketone. The Be(II) and Al(III) chelates were almost quantitalively extracted when a 1,72.10 mole.L TTA concentration was employed in the single phase solution. The single phase extraction of ion-pair association species were also studied in this ternary solution to investigated the behavior of Bi(III) iodide and Nb(V) or Ta(V) fluoride systems. The iodide complex was completely extracted when sufficiently high iodide / bismuth ratios were employed. The association complex formed was very stable and permited quantitative recovery of up to 200 mg of Bi(III) in the organic extract when a 1,2.10 mole.L iodide solution was employed for extraction, decreasing to 96% if the amount of metal was increased to 500 mg.The iodide complex was colored in SF solution and permitted the analytical determination of bismuth in single phase solution mixtures. Ta(V) fluoride extraction in the single phase was only partial in the studied conditions (about 25% when using 80 mg of metal in a 2,0 mole.L hydrofluoric acid solution) but easier than for Nb(V) fluoride which was poorly extracted under the same conditions. As in the conventional liquid-liquid extraction systems the performance of tantalum fluoride extraction was improved by adition of hydrochloric acid in the separation solutions or by use of cations of higher molecular weight in the homogeneous solution.

ASSUNTO(S)

quimica analitica separação (tecnologia)

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