Kinetic measurements were made for the sorption of copper ions from aqueous sulfate solutions with di(2-ethylhexyl)phosphoric acid-impregnated 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 mechanism, which considered reversibility of the sorption. A more rigorous model based on Fick’s law was then applied to justify the applicability of the modified shrinking-core model to the present sorption systems. 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.