This study is focused on the permeation characteristics of ester compounds from aqueous solutions through hydrophobic membrane; ethyl acetate (EA), propyl acetate (PA) and butyl acetate (BA). A surface-modified tube-type alumina membrane (Al2O3) was used for ester compounds recovery by vapor permeation. Experiments were performed to evaluate the effects of the feed concentration (0.15-0.60 wt.%) and feed temperature (30-50 degreesC) on the separation of EA, PA, and BA from dilute aqueous solutions. It was found that the permeation flux increased with increasing feed ester concentration and operating temperature. The fluxes of EA, PA, and BA at 0.60 wt.% feed concentration and 40 degreesC were 282, 526, 661 g/m(2) h, which were much higher than those of polymer membranes. The separation factors for the 0.15-0.60 wt.% feed solution of EA, PA, and BA at 40 degreesC were in the range of 28.1-93.9, 83.6-129.4, and 190.7-209.9, respectively. The membrane tested showed high flux and high selectivity. (C) 2002 Elsevier Science B.V. All rights reserved.