Porous hollow fiber membrane and a method for the removal of a virus by using the same

Claim 1

A method for the removal of a virus contained in an aqueous solution, which comprises providing a porous hollow fiber membrane comprising a porous polymer wall having a substantially annular cross-section and a hollow space defined by the inner wall surface of said porous polymer wall which hollow space extends in the longitudinal direction of said porous polymer wall, said porous polymer wall having pres which form through-passages passing from the inner wall surface to the outer wall surface of sid polymer wall, and wherein the inner and outer wall surfaces of said porous polymer wall have an in-a-plane average pore diameter of 0.01 to 10 μm, said in-a-plane average pore diameter being an average pore diameter as measured in a plane perpendicular to a radial direction of said annular cross-section, and said porous polymer wall has an in-a-plane porosity of not less than 10% measured in every plane perpendicular to a radial direction of said annular cross-section, said in-a-plane porosity varying continuously between said inner wall surface and said outer wall surface, wherein said in-a-plane porosity increases in the vicinity of each of said inner and outer wall surfaces and exhibits at least one minimum value between said inner and outer wall surfaces, said in-a-plane porosity at each of said inner and outer wall surfaces being at least 1.5 time the lowest value of the in-a-plane porosity within said porous polymer wall, and contacting the aqueous protein solution containing the virus with the inner or outer wall surface of the porous polymer wall of said membrane sufficiently while applying a transmembrane pressure, to cause the virus contained in the aqueous protein solution to be captured in the porous hollow fiber membrane while allowing the aqueous protein solution to permeate through the porous hollow fiber membrane.

Claim 2

A method for the removal of a virus contained in an aqueous solution, which comprises providing a porous hollow fiber membrane comprising a porous polymer wall having a substantially annular cross-section and a hollow space defined by the inner wall surface of said porous polymer wall which hollow space extends in the longitudinal direction of said porous polymer wall, said porous polymer wall having pres which form through-passages passing from the inner wall surface to the outer wall surface of sid polymer wall, and wherein the inner and outer wall surfaces of said porous polymer wall have an in-a-plane average pore diameter of 0.01 to 10 μm, said in-a-plane average pore diameter being an average pore diameter as measured in a plane perpendicular to a radial direction of said annular cross-section, and said porous polymer wall has an in-a-plane porosity of not less than 10% measured in every plane perpendicular to a radial direction of said annular cross-section, said in-a-plane porosity varying continuously between said inner wall surface and said outer wall surface, wherein said in-a-plane porosity increases in the vicinity of each of said inner and outer wall surfaces and exhibits at least one minimum value between said inner and outer wall surfaces, said in-a-plane porosity at each of said inner and outer wall surfaces being at least 1.5 time the lowest value of the in-a-plane porosity within said porous polymer wall, and contacting the aqueous protein solution containing the virus with the inner or outer wall surface of the porous polymer wall of said membrane sufficiently while applying a transmembrane pressure, to cause the virus contained in the aqueous protein solution to be captured in the porous hollow fiber membrane while allowing the aqueous protein solution to permeate through the porous hollow fiber membrane.