| abstract |
To provide a hollow fiber type semipermeable membrane which achieves both water permeability and salt rejection ability at high level, so as to conduct, with small membrane area, a water treatment utilizing concentration difference from liquid mixture of high concentration and high osmotic pressure. n A hollow fiber type semipermeable membrane comprising cellulose acetate, characterized in that, between an aqueous solution of 25°C having sodium chloride concentration of 35, 000 mg/L and freshwater of 25°C having sodium chloride concentration of 0 g/L at 0 MPa, the permeation flow rate flown from inner side to the outer side of the hollow fiber type semipermeable membrane is 60 to 180 L/m 2 /day, the outer diameter of the hollow fiber type semipermeable membrane is 100 to 350 µm, the inner diameter thereof is 50 to 250 µm and the hollow ratio thereof is 24 to 51%. |