PURPOSE: To easily improve an osmotic treatment process by removing substances inhibiting the selective permeability of osmotic membrane by adsorption in advance by using a polymer having a structure the same as or similar to that of the polymer forming the osmotic membrane.
CONSTITUTION: In the osmotic treatment of an aqueous solution containing substances inhibiting the selective permeability of osmotic membrane by adsorption on the osmotic membrane, a polymer having a structure the same as or similar to that of the polymer forming the osmotic membrane is brought into contact with the aqueous solution in advance so as to remove the said inhibiting substances by adsorption, and then the aqueous solution is passed through the osmotic membrane. The osmotic membrane used includes a composite film, etc., having the thin film of cellulose acetate film, aromatic polyamide film, polybenzimidazolone film, polybenzimidazole film, or thin films of polyamide, polyurea, etc. The use of the polymer having as much a great specific surface area as possible is advnatageous with respect to the efficiency of adsorption. For example, porous granular, fibrous, porous or nonporous thin films may be cited.
NOMA TAKASHI
HARA SHIGEYOSHI
