METAL SORPTION WITH EXTRACTANT-IMPREGNATED MACROPOROUS RESINS .2. CHEMICAL-REACTION AND PARTICLE DIFFUSION KINETICS

The rates of the sorption of zinc ions from aqueous sulfate solutions with di(2-ethylhexyl) phosphoric acid-impregnated Amberlite XAD macrop orous resins were measured in finite bath by a batch-contact time meth od. The sorption process was initially found to be controlled by a com bined chemical reaction and particle diffusion process using a provabl e modified shrinking,core model. A more rigorous model based on Fick's law was then developed to elucidate the sorption mechanism, and a pro cedure was suggested to simultaneously determine the reaction rate con stant and effective particle diffusivity.