Ceramic porous membrane and ceramic filter

Abstract

There are disclosed a ceramic porous membrane formed with less membrane formation times and having less defects, a small and uniform thickness and a high flux, and a ceramic filter. A silica membrane is formed on a titania UF membrane as an ultrafiltration membrane (a UF membrane) formed on a porous base member which is a microfiltration membrane (also referred to as an MF membrane) and having an average pore diameter smaller than that of the porous base member, and the silica membrane has an average pore diameter smaller than that of the titania UF membrane, and does not substantially permeates the titania UF membrane.

1 . A ceramic porous membrane which is formed on an ultrafiltration membrane having an average pore diameter of 2 to 20 nm and which does not substantially permeate pores of the ultrafiltration membrane.  
     
     
         2 . The ceramic porous membrane according to  claim 1 , which is formed on an intermediate layer having an average pore diameter of 1 to 5 nm on at least a surface that comes in contact with the ultrafiltration membrane having the average pore diameter of 2 to 20 nm, and which does not substantially permeate the pores of the ultrafiltration membrane.  
     
     
         3 . The ceramic porous membrane according to  claim 1 , wherein the ultrafiltration membrane is a titania membrane.  
     
     
         4 . The ceramic porous membrane according to  claim 1 , which is a silica membrane.  
     
     
         5 . A ceramic filter comprising: 
 a porous base member;    an ultrafiltration membrane formed on the porous base member and having an average pore diameter of 2 to 20 nm; and    a ceramic porous membrane which is formed on the ultrafiltration membrane and which does not substantially permeate pores of the ultrafiltration membrane.    
     
     
         6 . The ceramic filter according to  claim 5 , which has an intermediate layer having an average pore diameter of 1 to 5 nm on at least a surface that comes in contact with the ultrafiltration membrane between the ultrafiltration membrane and the ceramic porous membrane.  
     
     
         7 . The ceramic filter according to  claim 5 , wherein the ultrafiltration membrane is a titania membrane.  
     
     
         8 . The ceramic filter according to  claim 5 , wherein the ceramic porous membrane is a silica membrane.