Method of fabricating organic structure directing agent-free cha type zeolite membrane and membrane fabricated thereby

Abstract

The present invention relates to a method of fabricating an organic structure directing agent-free CHA type zeolite membrane and a membrane fabricated thereby, and more particularly to a method of fabricating a continuous CHA type zeolite membrane, which exhibits CO2/N2 and CO2/CH4 separation performances comparable with those of conventional membranes, in a cost-effective manner without a calcination process by hydrothermal synthesis using an alkali metal hydroxide without using an organic structure directing agent, and to a membrane fabricated thereby.

What is claimed is: 
     
         1 . An organic structure directing agent-free CHA type zeolite membrane which is fabricated by the method comprising:
 (a) preparing particles having a CHA structure;   (b) forming a seed layer by depositing the particles having the CHA structure on a support; and   (c) fabricating a CHA type zeolite membrane by conducting hydrothermal synthesis on the seed layer using a synthetic precursor solution containing an alkali metal and silica, and having a molar ratio of Si to Al of 45-55 at a temperature of 100-250° C. for 24-48 hours,   wherein the organic structure directing agent is added to step (a), and is not added to steps (b) and (c).   
     
     
         2 . The organic structure directing agent-free CHA type zeolite membrane of  claim 1 , wherein an alkali metal in the alkali metal hydroxide is selected from the group consisting of Li, Na, K and mixtures thereof. 
     
     
         3 . The organic structure directing agent-free CHA type zeolite membrane of  claim 1 , further comprising a step of drying after hydrothermally synthesizing in step of (c). 
     
     
         4 . The organic structure directing agent-free CHA type zeolite membrane of  claim 1 , wherein the support is one or more selected from the group consisting of alumina, polyimide, silica, glass, gamma alumina, mullite, zirconia, titania, yttria, ceria, vanadia, silicone, stainless steel and carbon. 
     
     
         5 . The organic structure directing agent-free CHA type zeolite membrane of  claim 1 , wherein the molar ratio of Si to Al is 50, and the hydrothermal synthesis is conducted at 175° C. 
     
     
         6 . A method of separating CO 2  from a mixture containing CO 2  and a molecule selected from the group consisting of CH 4 , N 2 , O 2 , C 2 H 4 , C 2 H 6 , C 3 H 6  and C 3 H 8 , by using the CHA type zeolite membrane of  claim 1 . 
     
     
         7 . The method of  claim 6 , wherein the method is performed at a temperature of 30-200° C. under dry conditions, and at a temperature of 75-200° C. under wet conditions.