JPS61209012A - Preparation of separation membrane - Google Patents

Abstract

PURPOSE:To obtain a gas separation membrane excellent in heat resistance and chemical resistance, by forming a membrane having fine pores to the surface of a phase splittable glass layer after phase splitting and eluting the glass phase rich in alkali subjected to phase splitting. CONSTITUTION:Phase splittable glass such as Na2O-B2O3-SiO2 type glass is used. In order to make phase splitting easy, the mol ratio of Na2O/B2O3 is set in the vicinity of 1/5 and 50% or more of SiO2 is contained in order to hold strength. A glass layer is applied to the surface of a ceramic porous body 2 having open pores 1 with a pore size of 0.5-30mum in a thickness of 10-500mum. After phase splitting treatment, such that heat treatment is per formed at 150-800 deg.C for 0.5hr or more, is performed, a metal or ceramic membrane 6 is formed to the surface of the glass layer 3 and elution treatment is performed at 90 deg.C or more by hot water, hydrochloric acid or sulfuric acid. The glass layer 3 comes to a porous body 8 rich in silica having fine pores 7 with a pore size of 10-5,000Angstrom .

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a separation membrane used in a wide range of applications such as gas separation, precision filtration, ultrafiltration, and reverse osmosis.

(Prior art) In the field of gas separation, which separates a specific gas from a mixed gas by the gas diffusion method, separation membranes with pores of several tens to hundreds of pores, which are much smaller than the mean free path of gas molecules, are used. is used. Organic polymer membranes are usually used as conventional separation membranes of this type, but they cannot be used at temperatures above 100°C, have poor chemical resistance and durability, and have various practical problems. is left behind. On the other hand, there is also a known method of manufacturing porous separation membranes by sintering metal powder or ceramic powder for the purpose of improving heat resistance, but separation membranes made by this method are membranes of 1 fi or less due to strength issues. It is difficult to increase the thickness, and as a separation membrane for gas separation, where it is desired to improve separation efficiency by reducing the membrane thickness as much as possible, it is still impractical. Therefore, as shown in Japanese Patent Application Laid-Open No. 59-59223,
Attempts have also been made to impregnate a porous body such as a ceramic sintered body with a diaphragm-forming component such as aluminum alcoholade or aluminum chelate in the form of a solution, and then dry and sinter it after hydrolysis to obtain a diaphragm made of a multilayered porous body. However, this method tends to leave cracks and air bubbles in the diaphragm when the water and organic binder in the solution scatters, and even if the pores in the diaphragm are controlled to have a pore size of several tens to hundreds of pores, the cranks will cause dozens of cracks. Most of the gas diffuses through the μ through-hole,
There was a drawback that it was difficult to perform the desired gas separation.

(Problems to be solved by the invention) The present invention solves these conventional problems and improves heat resistance,
Excellent chemical resistance and durability, and pore size of 5~ suitable for gas separation
It was completed with the aim of creating a method for manufacturing a separation membrane that can manufacture a separation membrane with a large number of 2,000 uniform pores without producing a crank.

(Means for Solving the Problems) The present invention involves phase-separating a phase-separable glass layer to separate it into a silica-rich glass phase and an alkali-rich glass phase. The method is characterized by forming a thin film having a large number of pores with a pore size of 5 to 2000, and then eluting an alkali-rich glass phase from the glass layer by elution treatment.

Phase separation of glass is the separation of two or more types of glass inside the glass phase, and generally, 0-separation is possible, which utilizes the separation of a silica-rich glass phase and an alkali-rich glass phase. Glass: Na, O-Bg03-3
ioz system, NatO-BxOs Si OH-heavy metal oxide system, NatO-BzOx -Ce O* ・
3 N bioz system, pJ a! O-P z05
-Sing system, Na, O-B, O, -3ioz-Gem
, 0 representative glasses are used, such as N a to
BxOs S i Ot glass is a homogeneous borosilicate glass that is heat treated to create a silica glass phase consisting of almost 5iot and Na.

It separates the glass phase whose main component is 0-BzOs on the order of several dozen people, and N is added to facilitate the phase separation.
a 寞0 / B g O2 should be in the vicinity of 115 in molar ratio, and in order to maintain strength after elution treatment, it is desirable to contain 50% or more of Sin. Such a phase-separable glass is heated and melted. Then, it is formed into a glass layer of arbitrary shape such as a thin plate or cylinder. In this case, it is preferable to have a thickness of 0.5 fin or more in order to obtain sufficient strength for handling.

In addition, in practice, as schematically shown in Figure 1, the temperature is 0°5~
A ceramic porous body (2) such as alumina, mullite, or cordierite having continuous pores (1) with a pore diameter of 30μ is coated with a phase-separable glass layer (3) to a thickness of 10 to 500μ. , it is preferable to have a strength even greater than that of the glass layer (3) alone.Next, such a glass layer (3) is subjected to a phase separation treatment to form a glass layer (3) as shown in FIG. 3) into a silica-rich glass phase (4
) and an alkali-rich glass phase (5).
Phase separation treatment is generally performed at 150 to 800°C for 0.5 hours or more.
i 400-700℃ when using OH glass
It will be held in When phase separation is carried out for a short time at a low temperature, the phase separation is fine, and the longer it is at a high temperature, the more the phase separation progresses, so the cross-sectional area of the alkali-rich glass phase (5)
After phase separation of glass N (3) is performed in this way, a metallic or ceramic thin film (6
) is formed by the gas phase. The gas phase method is defined as a method in which the substance to be formed into a thin film or its raw material is decomposed into atoms, molecules, or aggregates by applying heat or momentum, and then bonded or condensed on a substrate in another location. chemical reaction method (CVD method) and physical vapor deposition method (
pvD method). Chemical reaction methods are further classified into chemical reaction methods in a narrow sense, chemical transport methods, substrate reaction methods, spray methods, etc., but all of them involve changing the material that will form a thin film into a compound that easily vaporizes, transporting it through a gas phase, and then applying it to a substrate. This method involves forming a film by causing a chemical reaction on the surface. In addition, physical vapor deposition is a method such as vacuum evaporation, ion blasting, sputtering, and plasma that applies physical energy to a material in a vacuum to evaporate it, and then deposits it onto a substrate to form a film. It is. The thin film (6) produced on the glass layer (3) by these vapor phase methods can be processed while controlling the temperature of the substrate, atmospheric pressure, etc. to appropriate values. This results in a thin film (6) with a porous columnar structure and uniform pores with a pore size of 5 to 2000 pores. If the pore size is less than 5 pores, the gas permeation rate becomes low and practicality is lost. , if 2,000 people are tested, the gas separation performance will deteriorate, so the pore size should be 5 to 5.
It is assumed that control is performed so that the number of people is 2,000. The film thickness is suitably 10 Å to 100 μm, and the material may be oxides, carbides, nitrides, metals, or intermetallic compounds. After forming a thin film (6) on the surface of the glass layer (3) which has been phase-separated in this manner by a vapor phase method, it is coated with hot water of 90°C or higher or with O0 old to 0.5°C of 60-100°C. If elution treatment is performed using IN hydrochloric acid, sulfuric acid, nitric acid, etc., the alkali-rich glass phase (5) will be eluted while leaving 'gtIll (6) on the surface, as shown in Figure 4, and the glass phase will be dissolved. Layer +3) becomes a silica-rich porous body (8) with reticular pores (swords) with a pore size of 10 to 5000 people.

(Function) In this way, in the present invention, the thin film is formed by the vapor phase method on the surface of the phase-separated glass layer (3) which is flat and smooth and has a certain degree of strength.
A thin film (6) having uniform and minute pores of 0.00 mm can be stably formed. Moreover, by performing an elution process on the glass layer (3) after forming the thin film, the glass layer (3) alone can be made into a gas-permeable material having 10 to 5000 mesh pores (7) while leaving the thin film (6) on the surface. A thin film (6) having uniform and minute pores was formed on the surface of the glassy porous body (8), which can be made into a highly silica-rich glassy porous body (8) and therefore has high gas permeability. Separation membranes can be stably manufactured, and separation membranes with arbitrary pore diameters and membrane thickness can be manufactured by adjusting the thin film formation conditions using the gas phase method and the phase separation treatment conditions of the glass layer (3). .

Unlike conventional organic polymer membranes, the separation membrane obtained by the method of the present invention is made of glass, ceramic, or metal, so it has excellent heat resistance, chemical resistance, and durability, and is superior to conventional organic polymer membranes. Unlike multi-layered porous bodies obtained by impregnating aluminum alcolade etc. into ceramic sintered bodies, hydrolyzing them and drying them, there are no cracks, and gas separation can be carried out efficiently. .

(Example) Example I A flat plate with a thickness of 1 m was formed by melting a phase-separable glass of the Na-density 0-B, O, -S i O□ system, and then heated at 500°C.
, a phase separation treatment was performed for 12 hours. Altos was applied to the surface of the phase-separated glass using a gas phase chemical reaction method in a reaction tube.
Membrane thickness 10μ with average pore diameter 200 pores
A thin film was formed.

The raw material gas is AICIs, H! The carrier gas was At and Ox, and the reaction temperature was 900°C.

Then 90℃, 0. Perform elution treatment with IN hydrochloric acid,
The phase-separated glass layer was made into a silica-rich glassy porous body having network pores with an average pore diameter of 2,000 pores. As a result, a separation membrane was obtained in which a thin film having a thickness of 10 μm was formed on the surface of a glassy porous body by a vapor phase method.

Implementation N2 A flat plate with a thickness of 1 crane was formed by melting Nago-BgOi Si Ox-based glass that can be separated into phases, and then
Phase separation treatment was performed at 0°C for 10 hours. This was deposited in a reaction tube by vacuum evaporation to form a 2 μm-thick film of AI, O, and pores having an average pore diameter of 50 pores on the surface of a flat plate. The evaporation source was AI, the atmosphere was 0.1%, the pressure was 1 G-'torr, and the temperature of the flat plate made of phase-separated glass was maintained at 400°C. After cooling.

90℃, 0. The glass layer was subjected to an elution treatment with IN hydrochloric acid to form a glassy porous body made of silica and having network pores with an average pore diameter of too much. As a result, a separation membrane was obtained in which a thin film having a thickness of 2 μm was formed on the surface of a glassy porous body by a vapor phase method.

Example 3 Alumina granules were fired to produce particles with an average diameter of 1μ and a thickness of 1m.
Na on a flat plate made of a ceramic porous body.

0-Bgos S i OH-based phase-separable glass was applied to a thickness of 300 mm, heated and melted, and subjected to phase-separation treatment at 500° C. for 12 hours. This is coated with an AIN film with a thickness of 0.1 μm and an average pore size of 100 pores on the surface of a glass that can be phase-separated by sputtering in a reaction tube.
A thin film was formed. The cathode material was AI, and discharge was performed in an atmosphere of Ar5X10 torrsNx2X10-'' torr at a flat plate temperature of 200°C.After cooling, the temperature was 90°C and 0.5°C.
The glass layer of the alumina porous body was subjected to elution treatment with IN hydrochloric acid to form a glass porous body having network pores with an average pore diameter of 2,000 pores. As a result, the surface of the glassy porous body coated with the alumina porous body was coated with a film having a thickness of 0.00 mm by vapor phase method.
A separation membrane in which a 1 μm thin film was formed was obtained.

In addition to the separation membranes of Examples 1 to 3 above, as a comparative example, a separation membrane consisting only of a vitreous porous material with a thickness of 1 mm and an average pore diameter of 50 mm obtained by phase separation treatment of glass was prepared. , 50% (by volume) of H, Nz5o using a flow-through gas separation device
% mixed gas separation test was conducted. Supply side pressure 5.0
As a result of testing under the following conditions: kg/d, outlet pressure of 1 kg/cd, and temperature of 300°C, the results shown in the following table were obtained.

(Effects of the Invention) As is clear from the above description, the present invention provides uniform and fine pores with a diameter of 5 to 2000 by a vapor phase method on the surface of a phase-separated glass layer with a smooth surface and a certain degree of strength. After forming a thin film with pores, the glass layer is made into a porous material with high gas permeability by elution treatment with this thin film left in place. The separation membrane obtained by the method of the present invention has excellent pore uniformity, heat resistance, chemical resistance, durability, It has excellent mechanical strength, and in particular, a ceramic porous body whose surface is coated with a glass layer as shown in the figure shows excellent strength in practical use. Furthermore, the separation membrane obtained by the method of the present invention can be manufactured to any thickness and pore size, and is crack-free, making it particularly suitable for efficient gas separation. It is.

The separation membrane obtained according to the present invention is useful for recovering H2 from by-product gas in steel plants, and for synthesizing gas (Co) in C1 chemistry.
It is useful in the field of gas separation, such as adjusting the mixing ratio of -H,) and concentrating He from natural gas, but it is also useful for filtration of aqueous solutions and organic solvents, filtration of yeast and molds, and filtration of bacteria and viruses. In addition to the field of ultrafiltration, such as the concentration, recovery, and purification of proteins, concentration, recovery, and purification of physiologically active substances such as vaccines, enzymes, viruses, and nucleic acids, seawater,
It can also be effectively used in the field of reverse osmosis, such as desalination of salt water, production of pure water, and sterile water. Therefore, the present invention can greatly contribute to the development of industry by eliminating the problems associated with the production of conventional separation membranes of this type.

[Brief explanation of the drawing]

1 to 4 are partially enlarged sectional views schematically showing the manufacturing process of the separation membrane of the present invention. (3) Nigarasu layer, (61: Fl film.

Claims (1)

[Claims] 1. After phase-separating the phase-separable glass layer to separate it into a silica-rich glass phase and an alkali-rich glass phase, pores with a diameter of 5 to 2000 Å are formed on the surface by a vapor phase method. A method for producing a separation membrane, which comprises forming a thin film with a large number of pores, and then eluting an alkali-rich glass phase from the glass layer through elution treatment. 2. The method for producing a separation membrane according to claim 1, wherein the glass layer is coated on a ceramic porous body to a thickness of 10 to 500 μm. 3. The method for producing a separation membrane according to claim 1 or 2, wherein the thin film is formed to a thickness of 10 Å to 100 μ.