Abstract: The invention provides a process for fabricating a membrane filter that can stand up to filtration of nanometer-scaled fine particles or organic molecules, and a membrane filter having that filtration feature. Membrane filter 20 is disclosed. There is also the process for fabricating membrane filter 20 disclosed that is characterized by comprising the steps of mixing an aqueous solution containing a metal salt and an aqueous solution containing an alkali to prepare nanostrand solution 32 comprising a metal hydroxide, and filtrating nanostrand solution 32 through porous substrate 2 having pores to fabricate nanostrand sheet 3 comprising an accumulation of fibrous nanostrands on porous substrate 2 wherein the first pore formed between the nanostrands and extending through the nanostrand sheet from one surface side to another surface side has a maximum diameter of up to 5 nm.

Abstract: The invention provides a process for fabricating a membrane filter that can stand up to filtration of nanometer-scaled fine particles or organic molecules, and a membrane filter having that filtration feature. Membrane filter 20 is disclosed. There is also the process for fabricating membrane filter 20 disclosed that is characterized by comprising the steps of mixing an aqueous solution containing a metal salt and an aqueous solution containing an alkali to prepare nanostrand solution 32 comprising a metal hydroxide, and filtrating nanostrand solution 32 through porous substrate 2 having pores to fabricate nanostrand sheet 3 comprising an accumulation of fibrous nanostrands on porous substrate 2 wherein the first pore formed between the nanostrands and extending through the nanostrand sheet from one surface side to another surface side has a maximum diameter of up to 5 nm.