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. 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/m2/day, the outer diameter of the hollow fiber type semipermeable membrane is 100 to 350 ?m, the inner diameter thereof is 50 to 250 ?m and the hollow ratio thereof is 24 to 51%.

Abstract: A hollow fiber type semipermeable membrane which achieves both water permeability and selectivity in high level and performs efficient treatment using small membrane area utilizing the concentration difference from high concentration liquid having high osmotic pressure. The hollow fiber type semipermeable membrane is characterized in that, when an aqueous solution of 25° C. having NaCl concentration of 35 g/L and pressure of 1.0 MPa is flown into an outer side of the hollow fiber type semipermeable membrane having length of about 70 cm while freshwater of 25° C. having NaCl concentration of 0 g/L is flown into an inner side of one open end of the hollow fiber type semipermeable membrane and discharged from another open end at 10 kPa or less, the permeation flow rate is 30 to 70 L/m2/day. An inner diameter thereof is 50 to 200 ?m; and the hollow ratio thereof is 24 to 42%.

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. 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/m2/day, the outer diameter of the hollow fiber type semipermeable membrane is 100 to 350 ?m, the inner diameter thereof is 50 to 250 ?m and the hollow ratio thereof is 24 to 51%.

Abstract: A hollow fiber type semipermeable membrane which achieves both water permeability and selectivity in high level and performs efficient treatment using small membrane area utilizing the concentration difference from high concentration liquid having high osmotic pressure. The hollow fiber type semipermeable membrane is characterized in that, when an aqueous solution of 25° C. having NaCl concentration of 35 g/L and pressure of 1.0 MPa is flown into an outer side of the hollow fiber type semipermeable membrane having length of about 70 cm while freshwater of 25° C. having NaCl concentration of 0 g/L is flown into an inner side of one open end of the hollow fiber type semipermeable membrane and discharged from another open end at 10 kPa or less, the permeation flow rate is 30 to 70 L/m2/day. An inner diameter thereof is 50 to 200 ?m; and the hollow ratio thereof is 24 to 42%.

Abstract: A hollow fiber type reverse osmosis membrane including cellulose acetate, characterized in that the filtration rate and the salt rejection rate when an aqueous solution having sodium chloride concentration of 1,500 mg/L is filtered from outer side to inner side of the hollow fiber type reverse osmosis membrane at 25° C. and 1.5 MPa pressure are 180 to 350 L/m2/day and 90.0 to 99.0%, respectively and the outer diameter, the inner diameter and the hollow rate of the hollow fiber type reverse osmosis membrane are 100 to 280 ?m, 50 to 200 ?m and 24 to 42%, respectively. The hollow fiber type reverse osmosis membrane preferably has a dense layer near the outer surface, and thickness of the dense layer is 0.1 to 7 ?m.

Abstract: A hollow fiber type reverse osmosis membrane including cellulose acetate, characterized in that the filtration rate and the salt rejection rate when an aqueous solution having sodium chloride concentration of 1,500 mg/L is filtered from outer side to inner side of the hollow fiber type reverse osmosis membrane at 25° C. and 1.5 MPa pressure are 180 to 350 L/m2/day and 90.0 to 99.0%, respectively and the outer diameter, the inner diameter and the hollow rate of the hollow fiber type reverse osmosis membrane are 100 to 280 ?m, 50 to 200 ?m and 24 to 42%, respectively. The hollow fiber type reverse osmosis membrane preferably has a dense layer near the outer surface, and thickness of the dense layer is 0.1 to 7 ?m.