TY - JOUR
T1 - Interfacial versus aqueous phase reaction sites in the solvent extraction of metal ions
T2 - The ambaguity of correlation plots
AU - Osseo-Asare, K.
PY - 1988
Y1 - 1988
N2 - Correlation plots of rate constant versus a non-kinetic parameter such as limiting extractant interfacial area or extractant distribution coefficient have been used in the literature as a means of establishing the locale of the rate-determining step in metal-solvent extraction processes. A critical analysis of this approach is presented by considering the pertinent interfacial and acqueous phase equilibria as well as kinetics. It is shown that when the adsorption density of the extractant is below its saturation value, the adsorption density and the distribution coefficient of the extraction reagent are interrelated in such a way that in terms of the relevant mathematical expressions, an interfacial reaction can mimic a bulk aqueous phase reaction and vice verse. Thus, in order to meaningfully access the relative importance of aqueous phase and interfacial reaction sites, it is imperative that the extractant distribution and adsorption data be available over a wide range of extractant concentration.
AB - Correlation plots of rate constant versus a non-kinetic parameter such as limiting extractant interfacial area or extractant distribution coefficient have been used in the literature as a means of establishing the locale of the rate-determining step in metal-solvent extraction processes. A critical analysis of this approach is presented by considering the pertinent interfacial and acqueous phase equilibria as well as kinetics. It is shown that when the adsorption density of the extractant is below its saturation value, the adsorption density and the distribution coefficient of the extraction reagent are interrelated in such a way that in terms of the relevant mathematical expressions, an interfacial reaction can mimic a bulk aqueous phase reaction and vice verse. Thus, in order to meaningfully access the relative importance of aqueous phase and interfacial reaction sites, it is imperative that the extractant distribution and adsorption data be available over a wide range of extractant concentration.
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U2 - 10.1016/0166-6622(88)80062-3
DO - 10.1016/0166-6622(88)80062-3
M3 - Article
AN - SCOPUS:0024069596
SN - 0166-6622
VL - 33
SP - 209
EP - 215
JO - Colloids and Surfaces
JF - Colloids and Surfaces
IS - C
ER -