Patent ID: 9579610
Date: 2017-02-28
CPC Classifications: B01D

Claim:
1. A method for manufacturing a silica membrane filter, comprising: performing, at least once, a fired membrane forming operation having: a membrane forming step of applying, to a porous substrate, a precursor sol which is a sol of a silicon alcoxide including a p-tolyl group to form a precursor sol membrane; a drying step of drying the precursor sol membrane formed in the porous substrate to form a dried membrane; and a firing step of firing the dried membrane formed in the porous substrate to form a fired membrane, thereby preparing the silica membrane filter comprising the porous substrate and a silica membrane which is the fired membrane formed in the porous substrate, wherein a ratio of a total mass of the silica membrane to a total mass of the dried membrane is 38 mass % or more and 85 mass % or less, wherein an average value of opening diameters in a plurality of pores that are open in a surface of the porous substrate is from 3 to 10 nm, and wherein the silica membrane filter is subjected to a pervaporation test of passing a mixed liquid of ethanol, o-xylene and n-octane in a mass ratio of 33:33:33 through the silica membrane at a temperature of 50° by reducing the pressure from a side surface of the porous substrate at a vacuum degree of about 10 Torr, and trapping vapor permeated through the silica membrane filter to the side of the porous substrate in a trap cooled by liquid nitrogen, resulting in an ethanol permeation amount of at least 3.7 kg/m