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A mathematical model has been developed to simulate the performance of an integrated extraction-stripping process based on the use of hollow fiber contactors. The model allows one to predict the time-dependent concentration profiles of the two phases involved in an individual extraction or stripping process, or of the three phases involved in an integrated extraction-stripping process (two aqueous phases — feed and stripping — and one organic phase). The model includes as parameters operating conditions such as the initial concentrations, volumes and flowrates, distribution coefficients and overall mass transfer coefficients.

The proposed model allows one to simulate solvent extraction or stripping processes using hollow-fiber contactors, either with constant or variable distribution coefficients. It also allows the simulation of integrated extraction–stripping processes employing two hollow fiber contactors arranged in series. The model is based on (i) the extraction/stripping equilibria, obtained by independent experimentation, (ii) unsteady state differential mass balances to the elements of the experimental apparatus (hollow fiber contactor(s) and feed vessels), and (iii) operating conditions such as the initial concentrations, volumes and flowrates. By non-linear regression between experimental data and the simulation results, overall mass transfer coefficients can be obtained. The model has been satisfactorily validated (with values of the coefficient of determination in most cases higher than 0.99) for extraction, stripping and coupled simultaneous extraction– stripping processes, using experimental data from several systems, including cases involving simple physical extraction (with a constant distribution coefficient), reactive extraction, ion-exchange extraction, and coupled simultaneous coextraction of other species, with non-constant distribution coefficients.