Inorganic porous membrane

DETAILED DESCRIPTION What is claimed is: 1.
A multilayer inorganic porous membrane consisting of a monolayer or multilayer porous support having at least one surface integrally formed thereon with a porous thin layer having an average pore size less than that of the porous support, wherein a maximum pore size in the support surface is defined to be sized to preclude formation of pinholes and cracks when particles from a sol liquid are permeated easily into a portion of the maximum pores in the porous support.
2.
A multilayer inorganic porous membrane as recited in claim 1, wherein the porous support is made of a heat resistant inorganic material to form thereon a porous thin layer having an average pore size of less than 0.
1 micron.
3.
A multilayer inorganic porous membrane as recited in claim 1, wherein the following components A to E of less than 0.
5% by weight in terms of oxide are mixed with the porous membrane in an amount of less than 0.
5% by weight in terms of oxide.
A: Alkali metal compound B: Alkaline earth metal compound C: Yttrium, lanthanide compound D: VIII group compound E: Compound having a specific surface area of more than 10m.
sup.
2 /g and a cation radius of less than 0.
6 angstrom or more than 0.
9 angstrom.
4.
A multilayer inorganic porous membrane as recited in claim 1, wherein the porous thin layer is made of titanium oxide of 99.
5% purity.
5.
A multilayer inorganic porous membrane as recited in claim 1, wherein the porous thin layer is formed to have an average pore size of less than 800 angstrom and a thickness of less than 2 micron, and wherein an average pore size in the surface of the porous support formed thereon with the porous thin layer is less than 0.
1 micron.




Description:
BACKGROUND OF THE INVENTION 1.
Field of the Invention The present invention relates to inorganic porous membranes adapted for use in filtration, gas separation or the like and a process for the production of the inorganic porous membranes.
2.
Description of the Prior Art As one of such inorganic porous membranes as described above, there has been proposed a multilayer inorganic porous membrane consisting of a monolayer or multilayer porous support integrally provided on at least one surface thereof with a porous thin layer having an average pore size smaller than that of the porous support