A non-steady state model for the transport of iron(III) across n-decanol supported liquid membrane facilitated by D2EHPA

A non-steady state model to describe the permeation of iron(III) through a supported liquid membrane (SLM) based on n-decanol containing di-2-ethylhexyl phosphoric acid (D2EHPA) as a carrier is proposed. According to the model, two factors mainly contribute to the overall resistance for the iron(III) transport: the feed/organic interface chemical reaction and the diffusion of the complex Fe(III)-D2EHPA through the membrane liquid phase. The interface reaction is assumed first-order. The mole fractions of iron(III) in the three phases, the feed, the organic and the strip, were simulated by using a numerical method. Several series of experimental data were simulated and the simulated results fit very well the experimental data. The model accounts for the phenomenon of iron(III) retention in the organic phase and can simulate the iron(III) concentration in time in the membrane liquid phase. The rate controlling step for iron(III) transport from feed to strip is a combination between the interface reaction and the complex diffusion through the membrane.