Supported inorganic membranes

A method for producing a supported inorganic membrane capable of molecular sieving, wherein said membrane has a thickness of less than about 100 nm and comprises pores having average critical pore radii of less than about 5 .ANG., said method comprising the steps of:

• (a) contacting a porous substrate with an inorganic polymeric sol to produce a sol coated substrate, wherein said inorganic polymeric sol comprises inorganic polymers having a low fractal dimension;
• (b) drying said sol coated substrate to produce an inorganic polymeric coated substrate;
• and
• (c) calcining said inorganic polymeric coated substrate to produce said supported inorganic membrane.

A method for producing a supported inorganic membrane capable of molecular sieving, wherein said membrane has a thickness of less than about 100 nm and comprises pores having average critical pore radii of less than about 5 .ANG., said method comprising the steps of:

• (a) contacting a porous substrate with an inorganic polymeric sol to produce a sol coated substrate, wherein said inorganic polymeric sol comprises inorganic polymers having a low fractal dimension;
• (b) drying said sol coated substrate under conditions of low relative pressure of the liquid constituents of said sol to produce an inorganic polymeric coated substrate;
• and
• (c) calcining said inorganic polymeric coated substrate to produce said supported inorganic membrane.

A method of producing a supported inorganic membrane capable of molecular sieving, wherein said membrane has a thickness of less than about 100 nm and comprises pores having average critical pore radii of less than about 5 .ANG., said method comprising the steps of:

• (a) contacting a porous substrate with an inorganic silica polymeric sol to produce a sol coated substrate, wherein said inorganic polymeric sol comprises inorganic polymers having a fractal dimension of less than 2 and an average diameter greater than the porous substrate pore diameter;
• (b) drying said sol coated substrate under conditions of low relative pressure of the liquid constituents of said sol, wherein said conditions are substantially anhydrous, to produce an inorganic polymeric coated substrate;
• and
• (c) calcining said inorganic polymeric coated substrate to a temperature between about 400.degree. and 600.degree. C.;
• whereby said supported inorganic membrane capable of molecular sieving is produced.

A metal oxide surface derivatized supported inorganic membrane comprising:

• a porous substrate;
• an inorganic membrane coating the surface of said substrate, wherein said inorganic membrane has a thickness of less than about 100 nm, pores having average critical pore radii of less than about 5 .ANG., and a narrow pore radius distribution;
• and
• a metal oxide layer coating the surface of said inorganic membrane.

A metal oxide surface derivatized supported inorganic membrane comprising:

• an alumina porous substrate;
• an inorganic silica membrane coating the surface of said porous substrate, wherein said inorganic membrane has a thickness of less than about 100 nm, pores having average critical pore radii of less than about 5 .ANG., and a narrow pore radius distribution;
• and
• a titanium oxide layer coating the surface of said inorganic membrane, wherein said titanium oxide layer is 0.5 to 100 nm thick.

A method for producing a titanium oxide surface derivatized supported inorganic silica membrane, wherein said membrane has a thickness of less than about 100 nm and comprises pores having critical pore radii of less than about 5 .ANG., said method comprising the steps of:

• (a) contacting said supported inorganic silica membrane with a titanium alkoxide solution under substantially anhydrous conditions to produce a titanium alkoxide coated membrane;
• (b) drying said titanium alkoxide coated membrane under substantially anhydrous conditions;
• and
• (c) calcining said dried titanium alkoxide coated membrane to produce a supported inorganic silica membrane coated with a layer of titanium oxide.