Abstract: Selective liquid membranes have been traditionally employed for liquid/liquid and gas/liquid mass transfer in a wide range of applications. In particular, the Emulsion Pertraction Technology (EPT) using hollow fiber membrane contactors is a promising alternative to carry out the selective separation of metals from complex mixtures. However, the application of a new technology requires of reliable mathematical models and parameters that serve for design and optimization purposes allowing to accurate scale-up processes. This work reports the methodology for the development of a dynamic model to describe the kinetics of the EPT separation-concentration process applied to the regeneration of spent trivalent chromium-based passivating baths. The regeneration stage aims at the selective removal of Zn2+ dragged from previous steps in the plating line, not affecting the level of Cr3+ concentration in the passivating bath. In the case study the mathematical model was initially developed in a rigorous way and in a further analysis, a systematic method for its simplification was established. Then, the system of partial differential and algebraic equations obtained was integrated using the commercial software package ASPEN CUSTOM MODELER (from ASPENTECH) making possible the analysis of the model sensibility under different values of the operation variables. Finally, the model was validated with kinetic data obtained at laboratory scale.

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