STUDY OF SALT EFFECTS ON THE KINETICS OF SOLUTE TRANSFER AND EXTRACTION AT A FREE LIQUID/LIQUID INTERFACE

摘要

The effect of a salt on the kinetics of (ⅰ) transfer of acetic acid and (ⅱ) extraction of metal cations, Co~(2+) and Zn~(2+), by di(2-ethylhexyl) phosphoric acid (D2EHPA), was studied using the rotating membrane cell technique. In case (ⅰ), the kinetic rate of transfer could not be correlated with the value of the activity coefficient of solute in the aqueous phase. In case (ⅱ), it was found that the reaction is unlikely to be purely interfacial. The effect of salt on the kinetics was interpreted in terms of metal-(salt anion) association, transfer of extractant into the aqueous phase and primary electrolyte effect on the extractant-metal reaction in the aqueous phase.