Application of the Elovich equation to the kinetics of metal sorption with solvent-impregnated resins

The sorption rates of metal ions including Fe(III), Co(II), Ni(I I), Cu(II), and Zn(II) from sulfate solutions with macroporous resins containing bis(2-ethylhexyl)phosphoric acid (D2EHPA) were measured and compared in a batch stirred vessel. Experiments were carried out as a function of the pH and metal concentration in the aqueous phase, D2EHPA concentration in the resin phase, and temperature. The effect of impregnation methods of D2EHPA on the sorption rate was also investigated. It was shown that all sorption processes could be well described by the Elovich equation. For the examined systems there were similar trends of sorption rates with respect to the concentrations of metal ions and D2EHPA. With respect to the pH, however, three different trends were obtained depending on the magnitude of sorption rate. The apparent activation energy was obtained and used to discuss the rate-controlling mechanism.