The pervaporation process for acetic/water has been investigated with carbon molecular sieve (CMS)-filled polydimethylsiloxane (PDMS) membranes. The effects of feed temperature, feed acetic acid concentration and CMS content on the performance of the membranes have been studied. It is found that the addition of CMS can improve pervaporation behavior of PDMS membranes to some extent and greatly increases the strength and tenacity of membranes. At a CMS content of 20 wt.%, both permeation flux and separation factor reach maximum values. With an increase of the feed temperature, selectivity decreases and permeation flux increases, but flux of water increases faster than that of acetic acid. With the enhancement of feed concentration, flux and selectivity both get a rise and flux of acetic acid increases faster than that of water. (C) 2003 Elsevier B.V. All rights reserved.