Patent ID: 8556088

Claim:
A method of producing a nanoporous oxide ceramic membrane comprising: providing a metallic tube in a tubular or hollow fiber shape of predetermined dimension; placing a cathode inside the metallic tube in cylindrical symmetry to each other; placing a heat sink in contact or in close contact with an outer wall of the metallic tube so as to sufficiently absorb heat generated during anodization and to make the anodization process proceed in a steady state; filling an electrolyte to soak an inner wall surface of the metallic tube and the cathode with the electrolyte; and anodizing the metallic tube to produce a nanoporous oxide ceramic membrane, said anodizing performed by applying electric current between the metallic tube as an anode and the cathode while absorbing heat produced during the anodization from the outer wall of the metallic tube via the heat sink, wherein said anodizing is performed such that a portion of the wall from the inner wall of the metallic tube is anodized, and wherein the method further comprises: etching, after said anodizing, the inner or outer wall of the metallic tube; and, further anodizing a remaining non-anodized portion of the wall of the metallic tube so as to anodize an entire wall of the metallic tube between the outer wall and inner wall of the metallic tube.