The composite polydimethylsiloxane, (PDMS) membranes supported by Cellulose acetate (CA) were prepared by pre-wetting method for the separation of methanol, ethanol, n-propanol and acetone from water. The experiments were carried out to investigate the effects of operating parameters on the pervaporation performance and the results showed that the membranes exhibited high total permeation flux. A resistance-in-series model was applied to analyze the transport of the permeants. It was found that boundary-layer mass transfer coefficient was proportional to Re-0.5 and increased exponentially with temperature. The membrane mass transfer coefficient conformed to Arrhenius correlation and was independent of flow status. The estimated diffusivities of alcohols in membrane had a magnitude order of 10(-10) m(2.)s(-1) under a wider range of temperature, which was identical with those reported in the literature. (C) 2004 Elsevier B.V. All rights reserved.