A hollow fiber virus removal membrane for removing viruses from a protein-containing solution, wherein the hollow fiber virus removal membrane is made from an aging process of maintaining a raw spinning solution at 30° C. or higher and 40° C. or lower for 45 hours or more and 100 hours or less, wherein the raw spinning solution comprises a cuprammonium solution in which cellulose and a silicate are dissolved, and wherein the cellulose is selected from the group consisting of regenerated cellulose and native cellulose the hollow fiber virus removal membrane comprising:
- the cellulose;
- and
- a primary-side surface configured to have the protein-containing solution applied thereto, and
- a secondary-side surface configured to have a permeate that has permeated the hollow fiber virus removal membrane flow therefrom;
- wherein:
- a body of the hollow fiber virus removal membrane is configured such that:
- i) a bubble point is 0.5 MPa or more and 1.0 MPa or less;
- ii) an average pore size is 32.0 nm or more and 38.0 nm or less;
- iii) a value obtained by dividing a standard deviation of a value of an area of a spectrum of variation in brightness by an average of the value of the area of the spectrum of variation in the brightness is 0.01 or more and 0.30 or less,
- wherein the brightness is measured for a cross section of the hollow fiber virus removal membrane after 40 mL of solution containing gold colloids having a diameter of 30 nm is applied to a filtration area of 0.001 m2 of the primary-side surface, filtered under a pressure of 78.4 kPa, and penetrates into the body of the hollow fiber virus removal membrane to allow the hollow fiber virus removal membrane to capture the gold colloids, and the brightness being measured by an optical microscope;
- and
- iv) a site where gold colloids having a diameter of 30 nm or more and 40 nm or less are captured in the cross section of the hollow fiber virus removal membrane in a wet state has a thickness (T) in a range of 17.0 μm or more and 20.0 μm or less,
- wherein the thickness is measured after 40 mL of solution containing gold colloids having a diameter of 30 nm or more and 40 nm or less is applied to the filtration area of 0.001 m2 of the primary surface, filtered under the pressure of 78.4 kPa, and penetrates into the body of the hollow fiber virus removal membrane, and
- wherein the body of the hollow fiber virus removal membrane is further configured such that:
- a site where gold colloids having a diameter of 50 nm are captured is located at a place corresponding to 5% or more and 35% or less of the thickness of the hollow fiber virus removal membrane from the primary-side surface in the cross section of the hollow fiber virus removal membrane in a wet state after 40 mL of solution containing the gold colloids having a diameter of 50 nm is applied to the filtration area of 0.001 m2 of the primary-side surface, filtered under the pressure of 78.4 kPa, and penetrates into the body of the hollow fiber virus removal membrane,
- the site where gold colloids having a diameter of 40 nm are captured is located at a place corresponding to 8% or more and 50% or less of the membrane thickness from the primary-side surface in the cross section of the hollow fiber virus removal membrane in a wet state after 40 mL of solution containing the gold colloids having a diameter of 40 nm is applied to the filtration area of 0.001 m2 of the primary-side surface, filtered under the pressure of 78.4 kPa, and penetrates into the body of the hollow fiber virus removal membrane,
- the site where gold colloids having a diameter of 30 nm are captured is located at a place corresponding to 10% or more and 80% or less of the membrane thickness from the primary-side surface in the cross section of the hollow fiber virus removal membrane in a wet state after 40 mL of solution containing the gold colloids having a diameter of 30 nm is applied to the filtration area of 0.001 m2 of the primary-side surface, filtered under the pressure of 78.4 kPa, and penetrates into the body of the hollow fiber virus removal membrane, and
- wherein each of the solutions containing gold colloids are diluted with distilled water, 1.59% by volume of polyoxyethylene-naphthyl ether, and 0.20% by volume of poly (sodium 4-styrenesulfonate) to obtain each respective 40 mL of solution so that the absorbance at the maximum absorption wavelength of the gold colloids of the solution is 0.25 measured by an ultraviolet-visible spectrophotometer.