Gas separation: processes – Selective diffusion of gases – Selective diffusion of gases through substantially solid...
Reexamination Certificate
1999-06-10
2001-02-27
Spitzer, Robert H. (Department: 1724)
Gas separation: processes
Selective diffusion of gases
Selective diffusion of gases through substantially solid...
C096S011000, C427S245000, C428S034500
Reexamination Certificate
active
06193784
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for the production of a zeolite membrane possessing a highly selective separating function and a porous body having a zeolite membrane formed by the method of production.
Zeolite is a material with pores whose diameters can be controlled to a high degree and is capable of selecting molecular shapes based on the pore diameters. When it can be manufactured into a defect-free membrane, the manufacture has a very high significance because the inorganic membrane consequently obtained abounds in heat resistance and chemical durability.
2. Prior Art Statement
Heretofore, zeolite membranes have been formed by the method of forming a thin detached layer of zeolite membrane on a supporting porous membrane. This method, however, is incapable of either forming a defect-free zeolite membrane or producing a membrane possessing a highly functional separating quality on account of the persistence of defects due to the presence of crystal grain boundaries in zeolite.
The primary object of this invention is to provide a method for forming a zeolite membrane possessing a highly selective separating function in a defect-state.
SUMMARY OF THE INVENTION
The present inventors, after pursuing a series of studies with a view to fulfilling the object mentioned above in a method for producing a zeolite membrane by the reaction of hydrothermal synthesis, have perfected a method for forming a zeolite membrane by separating the raw material for the synthesis of a zeolite membrane into two liquid components (a) and (b), causing the two liquid components to permeate pores in a porous body from the opposite sides of the body, allowing the two liquid components to form an interface within the pores, and thereafter subjecting the porous body to the reaction of hydrothermal synthesis. They have discovered that this method is capable of easily forming a zeolite membrane possessing a highly selective separating function and not suffering from defects caused by crystal grain boundaries or the like because it precipitates zeolite crystals in the pores and requires only to form very small crystals. The present invention has been accomplished as a result.
Specifically, this invention is directed at providing a method for the production of a zeolite membrane identified below and a porous body having a zeolite membrane formed therein.
The method according to this invention effects the formation of a zeolite membrane by preparing raw materials (a) and (b) for the synthesis of zeolite, at least one of the raw materials containing water, positioning the raw material (a) for the synthesis of zeolite so as to contact one lateral face of a porous body and the raw material (b) therefor so as to contact the other lateral face of the porous body, causing the two raw materials (a) and (b) to permeate the porous body thereby forming an interface of the two raw materials in pores of the porous body, and inducing a reaction of hydrothermal synthesis at the interface.
Concrete ways of implementing the method include:
The method for causing the raw materials (a) and (b) to permeate the pores in the porous body comprises placing the porous body in a sealed container with the raw materials for the synthesis on opposite sides thereof and depressing the interior of the container to deaerate the porous body and promote permeation of the raw materials (a) and (b) under a reduced pressure.
The method wherein the raw materials for the synthesis are a liquid containing an aluminum compound and a liquid containing a silicon compound and the zeolite is amino acid zeolite.
The method wherein the raw materials for the synthesis are a liquid containing a silicon compound and a liquid containing a templating agent and the zeolite is silica light.
The method wherein the raw materials for the synthesis are a liquid containing an aluminum compound and a liquid containing a phosphoric acid compound or a liquid containing an aluminum compound and a liquid containing a germanium compound, or a liquid containing a silicon compound and a liquid containing a gallium compound and the zeolite is a non-aluminosilicate type zeolite. The method further comprising forming microcrystals of zeolite in the pores.
This invention further embraces a porous body having a zeolite membrane formed in the pores as produced by any of the methods described above and a membrane made of the porous body and used for separating and purifying a gas.
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Jin Tetsuro
Kuraoka Koji
Yazawa Tetsuo
Agency of Industrial Science & Technology, Ministry of Internati
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Spitzer Robert H.
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