Abstract: This invention consists of a composition useful for preparing a cellulose ester membrane comprising (1) a cellulose ester, (2) glycerol monoacetate, glycerol diacetate, glycerol triacetate, or mixtures thereof, and (3) optionally glycerol, wherein the cellulose ester membrane prepared from said composition is useful for a membrane liquid separation process such as microfiltration, ultrafiltration, dialysis, or reverse osmosis. In another aspect, this invention is an improved process for using said composition to prepare a cellulose ester membrane by forming a mixture of said composition, heating the mixture to a temperature at which the mixture becomes a homogeneous fluid, and extruding, molding, or casting the homogeneous fluid into a membrane. Another aspect of this invention consists of a cellulose ester membrane wherein the fabricated membrane contains glycerol monoacetate, glycerol diacetate, glycerol triacetate, or mixtures thereof, and optionally glycerol.