Recovery of sodium gluconate from model solutions by reverse osmosis

Abstract Recovery of sodium gluconate from aqueous solutions was studied batchwise in a pilot plant equipped with spiral-wound cellulose acetate or thin-film composite reverse osmosis membranes. The thin-film composite and cellulose acetate membranes had intrinsic membrane resistances ( R m ) of (3.8±0.1)×10 14 and (2.42±0.05)×10 14 m −1 and water fluxes of 60±2 and 91±2 dm 3 m −2 h −1 at a feed input absolute pressure of 41 bar and 40°C, respectively. Osmotic pressure was found to be the major resistance to permeation. A model based on the resistance concept was able to predict solvent permeation flux within 5–11% for both membranes.