Inorganic dual-layer microporous supported membranes

Abstract

The present invention provides for a dual-layer inorganic microporous membrane capable of molecular sieving, and methods for production of the membranes. The inorganic microporous supported membrane includes a porous substrate which supports a first inorganic porous membrane having an average pore size of less than about 25 Å and a second inorganic porous membrane coating the first inorganic membrane having an average pore size of less than about 6 Å. The dual-layered membrane is produced by contacting the porous substrate with a surfactant-template polymeric sol, resulting in a surfactant sol coated membrane support. The surfactant sol coated membrane support is dried, producing a surfactant-templated polymer-coated substrate which is calcined to produce an intermediate layer surfactant-templated membrane. The intermediate layer surfactant-templated membrane is then contacted with a second polymeric sol producing a polymeric sol coated substrate which is dried producing an inorganic polymeric coated substrate. The inorganic polymeric coated substrate is then calcined producing an inorganic dual-layered microporous supported membrane in accordance with the present invention.

What is claimed is:  
     
         1 . An inorganic microporous supported membrane, comprising: 
 a macroporous support;    a templated porous intermediate layer coating the support; and    a microporous layer coating the templated porous intermediate layer such that the microporous layer is capable of molecular sieving.    
     
     
         2 . The inorganic microporous supported membrane as claimed in  claim 1 , wherein: 
 the templated porous intermediate layer is an inorganic surfactant-templated silica layer; and    the microporous layer is an inorganic silica layer.    
     
     
         3 . The inorganic microporous supported membrane as claimed in  claim 2 , wherein: 
 the surfactant-templated porous intermediate layer having an average pore size of less than about 20 Å; and    the microporous layer having an average pore size of less than about 5 Å.    
     
     
         4 . The inorganic microporous supported membrane as claimed in  claim 1 , wherein: 
 the templated porous intermediate layer including an amphiphilic block copolymer.    
     
     
         5 . An inorganic microporous supported membrane, comprising: 
 a porous substrate;    a first inorganic porous membrane coating the substrate having an average pore size of less than about 25 Å; and    a second inorganic porous membrane coating the first inorganic membrane having an average pore size of less than about 6 Å.    
     
     
         6 . The inorganic microporous supported membrane as claimed in  claim 5 , wherein: 
 the first inorganic porous membrane has a pore diameter in a range of about 10 to 20 Å.    
     
     
         7 . The inorganic microporous supported membrane as claimed in  claim 6 , wherein: 
 the first inorganic porous membrane includes a surfactant-templated material.    
     
     
         8 . The inorganic microporous supported membrane as claimed in  claim 7 , wherein: 
 the surfactant-templated material is prepared from silica polymers and a surfactant powder.    
     
     
         9 . The inorganic microporous supported membrane as claimed in  claim 5 , wherein: 
 the second inorganic porous membrane is an inorganic silica membrane.    
     
     
         10 . The inorganic microporous supported membrane as claimed in  claim 5 , wherein: 
 the first inorganic porous membrane has a thickness of less than about 100 Å.    
     
     
         11 . The inorganic microporous supported membrane as claimed in  claim 5 , wherein: 
 the second inorganic porous membrane has an average pore size of between 2 and 5 Å.    
     
     
         12 . The inorganic microporous supported membrane as claimed in  claim 5 , wherein: 
 the second inorganic porous membrane has an average pore size of between 3 and 4 Å.    
     
     
         13 . The inorganic microporous supported membrane as claimed in  claim 5 , wherein: 
 the second inorganic porous membrane has a thickness less than about 100 nm.    
     
     
         14 . The inorganic microporous supported membrane as claimed in  claim 5 , wherein the porous substrate is an alumina substrate.  
     
     
         15 . The inorganic microporous supported membrane as claimed in  claim 6 , wherein: 
 the porous substrate has an average pore diameter ranging between 30 to 60 Å.    
     
     
         16 . A method for producing an inorganic dual-layered microporous supported membrane capable of molecular sieving, the method comprising: 
 contacting a porous substrate with a surfactant-template polymeric sol resulting in a surfactant sol coated membrane support;    drying the surfactant sol coated membrane support producing a surfactant-templated polymeric coated substrate;    calcining the surfactant-templated polymeric coated substrate to produce an intermediate layer surfactant membrane;    contacting the intermediate layer surfactant templated membrane with a second polymeric sol producing a polymeric sol coated substrate; and    drying the polymeric sol coated substrate producing an inorganic polymeric coated substrate;    calcining the inorganic polymeric coated substrate producing the inorganic dual-layered microporous supported membrane.    
     
     
         17 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 16 , wherein: 
 the step of calcining the inorganic polymeric coated substrate includes: 
 calcining the inorganic polymeric coated substrate at a first temperature producing a dual-layered supported membrane;  
 further calcining the dual-layered supported membrane at a second temperature to produce the inorganic dual-layered microporous supported membrane.  
   
     
     
         18 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 17 , wherein: 
 the step of calcining the inorganic polymeric coated substrate includes calcining under a vacuum.    
     
     
         19 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 18 , wherein: 
 the step of calcining the inorganic polymeric coated substrate includes calcining under a vacuum of less than about 6 pounds per square inch absolute (psia).    
     
     
         20 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 18 , wherein: 
 the step of calcining the inorganic polymeric coated substrate includes calcining under a vacuum of less than about 4 psia.    
     
     
         21 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 17 , wherein: 
 the step of calcining the inorganic polymeric coated substrate includes calcining at a temperature ranging from 200 to 400° C.    
     
     
         22 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 21 , wherein: 
 the step of calcining the inorganic polymeric coated substrate includes calcining at a temperature ranging from 250 to 350° C.    
     
     
         23 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 17 , wherein: 
 the step of calcining the dual-layered inorganic supported membrane includes calcining at a temperature ranging from 300 to 600° C.    
     
     
         24 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 23 , wherein: 
 the step of calcining the dual-layered inorganic supported membrane includes calcining at a temperature ranging from 400 to 500° C.    
     
     
         25 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 24 , wherein: 
 the step of calcining the dual-layered inorganic supported membrane includes calcining for between about 30 to 90 minutes.    
     
     
         26 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 16 , wherein: 
 the step of calcining the inorganic polymeric coated substrate includes calcining under a vacuum.    
     
     
         27 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 26 , wherein: 
 the step of calcining the inorganic polymeric coated substrate includes calcining under a vacuum of less than about 6 pounds per square inch absolute (psia).    
     
     
         28 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 27 , wherein: 
 the step of calcining the inorganic polymeric coated substrate includes calcining under a vacuum of less than about 4 pounds per square inch absolute (psia).    
     
     
         29 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 16 , wherein: 
 the step of heating the surfactant-template membrane substrate includes heating at a temperature between 500 to 600° C.    
     
     
         30 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 29 , wherein: 
 the step of heating the surfactant-template membrane substrate includes heating for between about 30 to 90 minutes.    
     
     
         31 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 16 , wherein: 
 the step of calcining the surfactant-templated polymeric coated substrate includes calcining at a temperature between 100-150° C.    
     
     
         32 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 16 , wherein: 
 the surfactant-template polymeric sol comprises silica polymers.    
     
     
         33 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 16 , wherein: 
 the second polymeric sol comprises silica polymers.    
     
     
         34 . The method for producing the inorganic dual-layered microporous supported membrane as claimed in  claim 16 , wherein: 
 the surfactant-template polymeric sol is prepared and deposited under conditions of low condensation rate; and    the second polymeric sol is prepared and deposited under a condition of low condensation rate.    
     
     
         35 . The method for producing an inorganic dual-layered microporous supported membrane as claimed in  claim 16 , wherein the method is performed under Class 100 clean room conditions.  
     
     
         36 . The method for producing an inorganic dual-layered microporous supported membrane as claimed in  claim 16 , wherein the step of drying the surfactant sol coated membrane support is performed under conditions of low relative pressure of the liquid constituents.  
     
     
         37 . A method for producing a supported membrane capable of molecular sieving, comprising: 
 preventing a subsequently deposited top microporous sol from penetrating further into the support including: 
 modifying a surface of the support; and  
   depositing the top microporous membrane on a modified support producing the supported membrane capable of molecular sieving.    
     
     
         38 . The method for producing a supported membrane as claimed in  claim 37 , wherein: 
 the step of modifying a surface of the support includes: 
 depositing an intermediate membrane on the surface.  
   
     
     
         39 . The method for producing a supported membrane as claimed in  claim 38 , wherein: 
 the step of depositing the intermediate membrane includes depositing an inorganic surfactant-templated silica intermediate layer having an average pore size of less than 25 Å.    
     
     
         40 . The method for producing a supported membrane as claimed in  claim 38 , wherein: 
 the step of depositing the intermediate membrane includes: 
 depositing a surfact-template sol onto the support;  
 drying the surfactant sol coated support;  
 calcining the dried surfactant sol coated support resulting in a surfactant supported membrane.  
   
     
     
         41 . The method for producing a supported membrane as claimed in  claim 38 , wherein: 
 the step of depositing an intermediate membrane including: 
 removing the surfactant-template by heating the surfactant supported membrane producing the modified support.  
   
     
     
         42 . The method for producing a supported membrane as claimed in  claim 38 , wherein: 
 the step of depositing the top microporous membrane includes: 
 depositing an inorganic polymeric sol on the modified support;  
 drying the polymeric sol coated support resulting in an inorganic polymeric sol coated support;  
 calcining the inorganic polymeric sol coated support resulting in a dual-layered supported membrane;  
 further calcining the dual-layered supported membrane resulting in the supported membrane capable of molecular sieving.