Asymmetric cellulose acetate based membranes usually employed in reverse osmosis as well as in separations in aqueous systems can possibly be applied in the so-called salinity process of energy generation. For these applications, membranes with a relatively high water permeability (sometimes also called water flux) and low salt permeability (or high salt rejection) are required. In this study the authors present the optimization of such membranes, which concerns the preparation parameters. The membranes studied were prepared from a solution whose composition were previously optimized.(4) The authors concluded that the optimum preparation parameters are as follows: thickness of the liquid film of 100 mu m; 30 s allowed for evaporation of the solvent; and temperature of coagulation bath of 0-4 degrees C and 80-85 degrees C as annealing temperature. (C) 2006 Wiley Periodicals, Inc. J Appl Polyrn Sci 103: 134-139, 2007