In this work, solvent recovery from soybean oil/hexane miscellas (1:3, w/w) was studied. Flat sheet polymeric membranes, polysulfone and polysulfone/polyamide based, used in reverse osmosis, nanofiltration and ultrafiltration, were tested. The effects of pressure (13-27 bar) and temperature (21-49 degrees C) on permeate flux, oil retention and separation of free fatty acids (FFA) were evaluated by a 2(2) complete factorial design, with three central points and four axial points. Increased pressure resulted in a higher permeate flux though the retention of oil and free fatty acids by the membranes has decreased. However, higher temperatures showed positive effects on the permeate flux, retention of oil and free fatty acids permeation. The highest oil retention (67.12%) was observed for low pressure (15 bar) and high temperature (45 degrees C). (c) 2006 Elsevier B.V. All rights reserved.