Method for membrane filtration purification of suspended water

Abstract

A method for membrane filtration purification of suspended water, comprising filtering the suspended water under an external pressure through a porous hollow fiber membrane comprising a polyolefin, a copolymer of olefin and halogenated olefin, halogenated polyolefin or a mixture thereof and having an open area ratio in an outer surface of not less than 20% and a pore diameter in a minimum pore diameter layer of not smaller than 0.03 μm and not larger than 1 μm.

1 . A method for membrane filtration purification of suspended water, comprising filtering the suspended water under an external pressure through a porous hollow fiber membrane comprising a polyolefin and having an open area ratio in an outer surface of not less than 20% and a pore diameter in a minimum pore diameter layer of not smaller than 0.03 μm and not larger than 1 μm.  
     
     
         2 . The method in accordance with  claim 1 , wherein the open area ratio in the outer surface is not less than 23%.  
     
     
         3 . The method in accordance with  claim 1 , wherein the open area ratio in the outer surface is not less than 25%.  
     
     
         4 . The method in accordance with any one of  claims 1  to  3 , wherein the pore diameter in the minimum pore diameter layer is not larger than 0.6 μm and a pore diameter in an inner surface is not smaller than 0.8 μm.  
     
     
         5 . The method in accordance with any one of  claims 1  to  3 , wherein the porous hollow fiber membrane has the inner diameter of not smaller than 0.5 mm and not larger than 3 mm and a thickness of not thinner than 0.1 mm and not thicker than 1 mm.