Composite membrane having a surface layer of an ultrathin film of cage-shaped zeolite and processes for production thereof

Claim 2

A permeable composite membrane, comprising: a porous support; and an ultrathin film of a cage-shaped non-granular zeolite composed of a 6-, 8-, 10-, or 12-membered oxygen ring window having aluminum or gallium atoms, silicon or germanium atoms, and oxygen atoms as constituent members, said ultrathin film of non-granular zeolite being a continuous surface layer on said porous support whereby said permeable composite membrane is adapted to selectively separate materials passing through said permeable composite membrane utilizing molecular sieve separation action and/or catalysis and whereby said separation is performed by a continuous non-phase change process.

Claim 3

The permeable composite membrane of claim 1 wherein the aluminum, gallium, silicon or germanium atoms are partly replaced by phosphorus, arsenic or beryllium atoms.

Claim 4

The composite membrane of claim 1 wherein the cage-shaped zeolite is of the alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium type.

Claim 5

The composite membrane of claim 1 wherein the cage-shaped zeolite is of H-type.

Claim 6

The composite membrane of claim 1 wherein the cage-shaped zeolite is of a rare earth metal type.

Claim 7

The composite membrane of claim 1 wherein the cage-shaped zeolite is of a transition metal type.

Claim 8

A process for producing a permeable composite membrane, comprising: (a) mixing an aluminate or gallate and a silicate or germanate in the form of an alkali metal salt, an alkaline earth metal salt, an ammonium salt or a lower alkyl-substituted ammonium salt with an aqueous solution of a hydroxide of an alkali metal, an alkaline earth metal, ammonium or an alkyl-substituted ammonium to form a gel, (b) passing the formed gel through a micro filter having a size of at least approximately 0.2 micron, (c) depositing uniformly the filtered gel on one smooth surface of a porous support or a dense support capable of being rendered porous by a chemical after-treatment to form a surface gel layer, (d) hydrothermally treating the formed surface gel layer at a temperature of at least 30° C. to crystallize the gel thereby forming an ultrathin film of cage-shaped non-granular zeolite being a continuous surface layer on said support, (e) if required, reducing the content of the alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium in the crystallized gel to not more than 1% by an ion exchange treatment, (f) when the support is dense, chemically treating it to render it porous, and (g) washing and drying the resulting permeable composite membrane.

Claim 9

A process for producing a permeable composite membrane, comprising: (a) mixing an aluminate or gallate and a silicate or germanate in the form of an alkali metal salt, an alkaline earth metal salt, an ammonium salt or a lower alkyl-substituted ammonium salt with an aqueous solution of a hydroxide of an alkali metal, an alkaline earth metal, ammonium or an alkyl-substituted ammonium to form a gel, (b) passing the formed gel through a micro filter having a size of at least approximately 0.2 micron, (c) depositing uniformly the filtered gel on one smooth surface of a porous support or a dense support capable of being rendered porous by a chemical after-treatment to form a surface gel layer, (d) hydrothermally treating the formed surface gel layer at a temperature of at least 30° C. to crystallize the gel thereby forming an ultrathin film of cage-shaped non-granular zeolite being a continuous surface layer on said support, (e) if required, reducing the content of the alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium in the crystallized gel to not more than 1% by an ion exchange treatment, (f) when the support is dense, chemically treating it to render it porous, and (g) washing and drying the resulting permeable composite membrane.

Claim 10

A process for producing a permeable composite membrane, comprising: (a) forming a continuous ultrathin film of an alloy composed of aluminum or gallium and silicon or germanium on one smooth surface of a porous support or a dense support capable of being rendered porous by a chemical after-treatment, (b) subjecting the ultrathin alloy film to an oxidation treatment, (c) dipping the oxidized ultrathin film in an aqueous solution of a hydroxide of an alkali metal, an alkaline earth metal, ammonium or an alkyl-substituted ammonium to form a surface gel layer, (d) hydrothermally treating the formed surface gel layer at a temperature of at least 30° C. to crystallize the gel thereby forming the desired cage-shaped zeolite crystals, said crystals being a continuous surface layer on said support, (e) if required, reducing the content of the alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium in the crystallized gel to not more than 1% by an ion-exchange treatment, (f) when the support is dense, chemically treating it to render it porous, and (g) washing and drying the resulting permeable composite membrane.

Claim 11

A process for producing a permeable composite membrane, comprising: (a) forming a continuous ultrathin film of an alloy composed of aluminum or gallium and silicon or germanium on one smooth surface of a porous support or a dense support capable of being rendered porous by a chemical after-treatment, (b) subjecting the ultrathin alloy film to an oxidation treatment, (c) dipping the oxidized ultrathin film in an aqueous solution of a hydroxide of an alkali metal, an alkaline earth metal, ammonium or an alkyl-substituted ammonium to form a surface gel layer, (d) hydrothermally treating the formed surface gel layer at a temperature of at least 30° C. to crystallize the gel thereby forming the desired cage-shaped zeolite crystals, said crystals being a continuous surface layer on said support, (e) if required, reducing the content of the alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium in the crystallized gel to not more than 1% by an ion-exchange treatment, (f) when the support is dense, chemically treating it to render it porous, and (g) washing and drying the resulting permeable composite membrane.

Claim 12

A process for producing a permeable composite membrane, comprising: (a) plating one smooth surface of a porous metal support or a dense metal support capable of being rendered porous by a chemical after-treatment, with a mixture of an aluminum or gallium salt and a silicon or germanium salt by oxidation-reduction reaction in accordance with an electroless plating technique, (b) oxidizing the resulting plated ultrathin film, (c) dipping the oxidized ultrathin film in an aqueous solution of a hydroxide of an alkali metal, an alkaline earth metal, ammonium or an alkyl-substituted ammonium to form a surface gel layer, (d) hydrothermally treating the resulting surface gel layer at a temperature of at least 30° C. to crystallize the gel thereby forming the desired cage-shaped zeolite crystals, said crystals being a continuous surface layer on said support, (e) if required, reducing the content of the alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium in the crystallized gel to not more than 1% by an ion-exchange treatment, (f) when the porous support is dense, chemically treating it to render it porous, and (g) washing and drying the resulting permeable composite membrane.

Claim 13

A process for producing a permeable composite membrane, comprising: (a) plating one smooth surface of a porous metal support or a dense metal support capable of being rendered porous by a chemical after-treatment, with a mixture of an aluminum or gallium salt and a silicon or germanium salt by oxidation-reduction reaction in accordance with an electroless plating technique, (b) oxidizing the resulting plated ultrathin film, (c) dipping the oxidized ultrathin film in an aqueous solution of a hydroxide of an alkali metal, an alkaline earth metal, ammonium or an alkyl-substituted ammonium to form a surface gel layer, (d) hydrothermally treating the resulting surface gel layer at a temperature of at least 30° C. to crystallize the gel thereby forming the desired cage-shaped zeolite crystals, said crystals being a continuous surface layer on said support, (e) if required, reducing the content of the alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium in the crystallized gel to not more than 1% by an ion-exchange treatment, (f) when the porous support is dense, chemically treating it to render it porous, and (g) washing and drying the resulting permeable composite membrane.

Claim 14

A process for producing a permeable composite membrane, comprising: (a) forming a continuous ultrathin film of a metal oxide comprising aluminum or gallium and silicon or germanium on one smooth surface of a porous support or a dense support capable of being rendered porous by a chemical after-treatment, (b) dipping the ultrathin film of the metal oxide in an aqueous solution of a hydroxide of an alkali metal, an alkaline earth metal, ammonium or an alkyl-substituted ammonium to form a surface gel layer, (c) hydrothermally treating the formed surface gel layer at a temperature of at least 30° C. to crystallize the gel thereby forming the desired cage-shaped zeolite crystals, said crystals being a continuous surface layer on said support, (d) if required, reducing the content of the alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium in the crystallized gel to not more than 1% by an ion-exchange treatment, (e) when the support is dense, chemically treating it to render it porous, and (f) washing and drying the resulting permeable composite membrane.

Claim 15

A process for producing a permeable composite membrane, comprising: (a) forming a continuous ultrathin film of a metal oxide comprising aluminum or gallium and silicon or germanium on one smooth surface of a porous support or a dense support capable of being rendered porous by a chemical after-treatment, (b) dipping the ultrathin film of the metal oxide in an aqueous solution of a hydroxide of an alkali metal, an alkaline earth metal, ammonium or an alkyl-substituted ammonium to form a surface gel layer, (c) hydrothermally treating the formed surface gel layer at a temperature of at least 30° C. to crystallize the gel thereby forming the desired cage-shaped zeolite crystals, said crystals being a continuous surface layer on said support, (d) if required, reducing the content of the alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium in the crystallized gel to not more than 1% by an ion-exchange treatment, (e) when the support is dense, chemically treating it to render it porous, and (f) washing and drying the resulting permeable composite membrane.

Claim 16

A process for producing a permeable composite membrane, comprising: (a) forming a continuous ultrathin film of one of an oxide of aluminum or gallium and an oxide of silicon or germanium on one smooth surface of a porous support or a dense support capable of being rendered porous by a chemical after-treatment, (b) dipping the support in an aqueous solution of hydroxide of an alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium to gel the oxide of the ultrathin film and the oxide of the support adjacent the ultrathin film, (c) hydrothermally treating the resulting gel at a temperature of at least 30° C. to crystallize the gel thereby forming the desired cage-shaped zeolite crytals, said crystals being a continuous surface layer on said support, (d) if required, reducing the content of the alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium in the crystallized gel to not more than 1% by an ion-exchange treatment, (e) when the support is dense, chemically treating it to render it porous, and (f) washing and drying the resulting permeable composite membrane.

Claim 17

A process for producing a permeable composite membrane, comprising: (a) forming a continuous ultrathin film of one of an oxide of aluminum or gallium and an oxide of silicon or germanium on one smooth surface of a porous support or a dense support capable of being rendered porous by a chemical after-treatment, (b) dipping the support in an aqueous solution of hydroxide of an alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium to gel the oxide of the ultrathin film and the oxide of the support adjacent the ultrathin film, (c) hydrothermally treating the resulting gel at a temperature of at least 30° C. to crystallize the gel thereby forming the desired cage-shaped zeolite crytals, said crystals being a continuous surface layer on said support, (d) if required, reducing the content of the alkali metal, alkaline earth metal, ammonium or alkyl-substituted ammonium in the crystallized gel to not more than 1% by an ion-exchange treatment, (e) when the support is dense, chemically treating it to render it porous, and (f) washing and drying the resulting permeable composite membrane.