METAL SORPTION WITH EXTRACTANT-IMPREGNATED MACROPOROUS RESINS .1. PARTICLE DIFFUSION KINETICS

Kinetic measurements were made for the sorption of copper ions from aq ueous sulfate solutions with di(2-ethylhexyl)phosphoric acid-impregnat ed Amberlite XAD macroporous resins in finite bath by a batch-contact time method. The sorption process of copper was first determined to be controlled by particle diffusion using a modified shrinking-core mech anism, which considered reversibility of the sorption. A more rigorous model based on Fick's law was then applied to justify the applicabili ty of the modified shrinking-core model to the present sorption system s. The effective particle diffusivity had an order of 10(-12) (in m(2) s(-1)), which was in agreement with those obtained for chelating ion- exchange processes.