In this work a predictive mathematical model has been developed to simulate the membrane-based solvent extraction of phenylglycine (PhgH) from alkaline solutions by trioctylmethylammonium chloride (TOMAC) (10%, v/v) in 1-decanol and the simultaneous membrane-based solvent stripping by chloride solutions using hollow fiber contactors. The model allows to predict the time-dependent concentration profiles of the three phases involved in the process, as a function of operating parameters (volumes, concentrations and volumetric flow rates), extraction mechanism parameters (distribution coefficients and equilibrium constants) and mass transfer coefficients. © 2005 Elsevier B.V. All rights reserved.