This paper has applied a simple model (H2CrO4 + Aliquat 336 <----> complex) to the mass transfer mechanism of Cr(VI) with Aliquat 336 in a batch-type, supported liquid membrane module. Concentrations at pH 3 are as follows: 0.019 kruol/m(3) less than or equal to Aliquat 336 less than or equal to 0.035 kmol/m(3) and 20 g/m(3) less than or equal to Cr (VI) less than or equal to 500 g/m(3). The measured values of forward- and backward-reaction rate constants between Cr(VI) and Aliquat 336 were used to simulate the model with the mass conservation equation and associated boundary conditions. Comparison between the experimental and simulated facilitated factors of Cr(VI) transport led to classification of reaction regions.