Development of novel water treatment process based on forward osmosis
In recent years, a forward osmosis (FO) process has attracted attention as a novel water separation technic for a desalination process or a process for concentrating foods, beverages, food additives, and bioproducts. In the FO process, water molecules permeate through a semipermeable membrane from a feed solution (FS) with lower osmotic pressure to a draw solution (DS) with a higher osmotic pressure. The driving force for water permeation in the FO process is the osmotic pressure difference between the DS and the FS (Fig. 1). Thus, the FO process requires neglectable energy for the water permeation compared to a conventional reverse osmosis (RO) process requiring a high pressure. Our group developed the FO membranes with high ammonia rejection (Fig. 2) and the DS with thermo-responsible materials (Fig. 3).
Fig. 1 Schematic illustration of the forward osmosis membrane process
Fig. 2 Illustration of the forward osmosis membrane with high ammonium ion rejection
Fig. 3 Draw solution with USCT-type thermo-responsive phase separation property