The volumetric overall mass transfer coefficients were investigated in a pilot scale perforated rotating disc contactor (PRDC) of 113 mm internal diameter, using axial diffusion model for two different liquid-liquid systems. The effects of operating parameters including the disc rotational speed and dispersed and continuous phase velocities on the mass transfer performance are investigated. The previous models for dispersed phase overall mass transfer coefficient were reviewed and compared with the experimental data. The results show that the previous correlations do not have enough accuracy for prediction of mass transfer performance in this extractor. Effective diffusivity is applied instead of molecular diffusivity in GrOber equation and enhancement factor is predicted from experimental data as a function of holdup of the dispersed phase, Reynolds number and Eatvos number. Good agreement between prediction and experiments was found for all operating conditions that were investigated. (C) 2015 Elsevier B.V. All rights reserved.