Abstract
Distillation is widely used for concentration of aqueous organic solvent solutions, but it consumes large amounts of energy. Membrane separation is energy–efficient for concentration, but conventional reverse osmosis (RO) method has limitations in the degree of concentration because of high osmotic pressure of concentrated solution. Osmotically Assisted Reverse Osmosis (OARO) is a method that enables high concentration at relatively low pressure. We applied the OARO method to the high concentration of aqueous organic solvent solutions. Dilute solutions of organic solvents such as isopropanol (IPA) and N,N–dimethylformamide (DMF) were successfully concentrated to 20 ～ 40 wt% by OARO with a high yield. OARO is useful for energy–efficient concentration and recovery of organic solvents from industrial wastewater containing organic solvents.
