Characterisation of nickel(II) extraction by 2-hydroxy-5-nonylacetophenone oxime (LIX 84) in a micellar phase
Data(s) |
23/10/2003
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Resumo |
The properties of the nickel(II)/2-hydroxy-5-nonylacetophenone oxime (HNAPO), an active ingredient in LIX 84, extraction system were characterised in a micellar system. The extinction coefficient, λ<sub>max </sub>of HNAPO (316 nm) and the Ni<sup>2+</sup> complex (387 nm) in a neutral micellar system, poly dispersed octa-ethyleneglycol mono-<i>n</i>-dodecyl ether (G<sub>12</sub>A<sub>8</sub>) were determined as 3100 and 3500 M<sup>−1</sup> cm<sup>−1</sup>, respectively. HNAPO was found to have a neutral micellar phase and bulk aqueous phase p<i>K</i><sub>a</sub> of 11.5 and 12.5, respectively. The extraction equilibrium constant, <i>K</i><sub>ex,</sub> was determined to be 10<sup>−8.0</sup>, and the deviation from theory observed at high pH can be accounted for by consideration of the competition for nickel(II) ions by hydroxide ions and HNAPO. A micellar phase of octa-ethyleneglycol mono-<i>n</i>-dodecyl ether (C<sub>12</sub>E<sub>8</sub>) was determined to be an appropriate model of the free oil/water interface from the solubilised location of HNAPO. Utilising the interfacial probe, 4-heptadecyl-7-hydroxy coumarin (HHC) allowed the determination of the electrostatic surface potential of mixed micelles of G<sub>12</sub>A<sub>8</sub> and sodium dodecyl sulphate (SDS) or dodecyl trimethyl ammonium chloride (DTAC). The electrostatic surface potential was a linear function of the number of additional surfactant monomers within the G<sub>12</sub>A<sub>8</sub> micelle, for the concentration range studied. For G<sub>12</sub>A<sub>8</sub>/DTAC mixed micelles, the surface potential was given by +1.1 mV per DTAC molecule per micelle, and for G<sub>12</sub>A<sub>8</sub>/SDS mixed micelles the relationship was −1.4 mV per SDS molecule per micelle.<br /> |
Identificador | |
Idioma(s) |
eng |
Publicador |
Elsevier |
Relação |
http://dro.deakin.edu.au/eserv/DU:30019608/dyson-characterisationofnickel-2003.pdf http://dx.doi.org/10.1016/S0927-7757(03)00386-8 |
Direitos |
2003, Elsevier B.V. |
Palavras-Chave | #solvent extraction #micellar phase #equilibria #electrostatic surface potential #probe location |
Tipo |
Journal Article |