Cellulose triacetate forward osmosis membranes: preparation and characterization

Cellulose triacetate (CTA) forward osmosis membranes were prepared by immersion precipitation. Following a standard recipe for the preparation of reverse osmosis membranes, the concentrations of polymer, additives (lactic acid, methanol), and solvent composition in the casting solution were investigated with respect to membrane permeation and salt rejection. The membrane preparation parameters including the evaporation time and the coagulation bath temperature were investigated as well. A CTA membrane with a quasi double-skinned morphology was obtained. The CTA FO membrane showed a water flux higher than 10 kg/m2 h using 2 M glucose water solution as the draw solution and 0. 5 M NaCl as feed. A NaCl rejection of 95% was obtained.