MODELING OF MASS-TRANSFER IN FACILITATED SUPPORTED LIQUID-MEMBRANE TRANSPORT OF PALLADIUM(II) USING DI-(2-ETHYLHEXYL) THIOPHOSPHORIC ACID

The permeation of Pd(II) through supported liquid membranes (SLMs) imp regnated with di-(2-ethylhexyl) thiophosphoric acid (DEHTPA) in kerose ne has been investigated. A model is reported describing the transport mechanism which consists of: diffusion process through the feed aqueo us diffusion layer, fast interfacial chemical reaction and diffusion t hrough the membrane. The experimental data are quantitatively explaine d by mathematical equations describing the rate of transport. Differen t rate-controlling processes take place as long as the metal transport occurs. High selectivity in the separation of Pd(II) against Fe(III), Pt(IV), Rh(III) and Zn(II) is achieved and the lifetime of the membra nes is also studied. (C) 1998 Elsevier Science B.V. All rights reserve d.