JPS61209004A - Separation membrane and its preparation - Google Patents

Abstract

PURPOSE:To obtain a separation membrane excellent in heat resistance, chemical resistance and durability, generating no crack and suitable for the separation of gas, by forming a metallic or ceramic membrane having fine pores with a specific pore size to the surface of a vitreous porous body obtained by the phase splitting treatment of glass. CONSTITUTION:Phase splittable glass of a Na2O-B2O3-SiO2 system is applied to a flat plate 2 comprising a ceramic porous body and melted under heating to form a glass layer 3 while the coated flat plate is treated in a reaction tube by a gaseous phase method to form a membrane having uniform fine pores with a pore size of 5-2,000Angstrom comprising Al2O3 to the surface of the glass layer 3. Next, the glass layer 3 is subjected to phase splitting treatment so as to a adjust the cross sectional area of the glass phase rich in alkali to 10-5,000Angstrom under a regulated phase splitting treatment condition. Thereafter, elution treatment is performed to elute the glass phase rich in alkali to obtain a separation membrane comprising a vitreous porous body 8 rich in silica having a reticulated fine pores 7 with a pore size of 10-5,000Angstrom while the membrane 4 is left on the surface thereof.

Description

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

(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. Conventional separation membranes of this type usually use mechanical polymer membranes, but they cannot be used at temperatures above 100°C and have poor chemical resistance and durability. Problems remain. On the other hand, it is also known to manufacture porous separation membranes by sintering metal powders or ceramic powders for the purpose of improving heat resistance, but separation membranes made by this method have a strength of less than 1 dragon. It is difficult to make the film thick enough, and it is still impractical as a separation membrane for gas separation, where it is desired to make the film as thin as possible to improve separation efficiency. As shown in Japanese Patent Publication No. 59-59223, a porous body such as a ceramic sintered body is impregnated with a diaphragm-forming component such as aluminum alcoholade or aluminum chelate in the form of a solution, and after hydrolysis, it is dried and fired to form a multilayered body. Attempts have also been made to obtain a diaphragm made of a porous material, but this method tends to leave cracks and air bubbles in the diaphragm when the water in the solution and the organic binder scatter, and the pores in the diaphragm are reduced to tens of pores in diameter. Even if controlled by ~100 people, most of the gas would diffuse through the through holes of several tens of microns created by the crank, making it difficult to achieve desired gas separation.

(Problems to be solved by the invention) The present invention solves these conventional problems and improves heat resistance,
A separation membrane with a large number of pores of 5 to 2,000 pores in diameter, which has excellent chemical resistance and durability, and which does not cause cracks even when the membrane is extremely thin, and a method for manufacturing the same. It is complete.

(Means for Solving the Problems) The present invention is characterized in that the pore size obtained by phase separation treatment of glass is 10 to 5.
On the surface of a glassy porous body with 000 Å network pores,
A first invention relating to a separation membrane characterized in that a thin film of metal or ceramic is formed from a gas phase having pores with a pore size of 5 to 2000 people, and A metal or ceramic thin film having pores with a pore diameter of 5 to 2,000 is formed by a phase method, and the glass layer is subjected to a decentralization treatment, and then the phase-separated glass layer is subjected to an elution treatment to form a glass layer of 10 to 2,000. This invention also consists of a second invention relating to a method for manufacturing a separation membrane characterized in that it is a glassy porous body having 5,000 net-like pores.

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. As for glass, Na go -BzOs
S i Os system, Nato-BIOs Sing
- Heavy metal oxide system, Na, O-B.

02 Ce Ol ・3 N 1) gos system, Na
, O-P.

0, -3t0. system, N a tOBtus S i
0H-GeO, etc. glasses are used.
a to BzOs -S L O1 glass is a homogeneous borosilicate glass with a silica glass phase consisting almost only of 5i01 and NagO-B by heat treatment.
, O, and the glass phase mainly composed of N a z O/ to facilitate phase separation.
B t O3 should be in the vicinity of 175 in molar ratio, and in order to maintain strength after elution treatment, it is desirable to contain 5tat in an amount of 50% or more. Such phase-separable glass is heated and melted to form a glass layer of any shape such as a thin plate or cylinder. In this case, it is preferable to have a thickness of 0.5 fi 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~
Assuming that the surface of a ceramic porous body (2) such as alumina, mullite, or cordierite having continuous pores with a pore diameter of 30μ (+1) is coated with a phase-separable glass layer (3), only the glass layer (3) is coated. It is preferable to give the glass layer (3) a strength even greater than that of the glass layer (3). Next, a thin film (4) of metal or ceramic is applied to the surface of the phase-separable glass layer (3) by a vapor phase method as shown in Fig. 2. is formed. The vapor phase method is defined as a method of applying heat or momentum to a substance to be formed into a thin film or a substance consisting of its raw materials, decomposing it into atoms, molecules, or aggregates, and then bonding or S-contracting them onto a substrate in another location. It is broadly divided into 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. If the thin film (4) produced on the substrate by these vapor phase methods is processed while controlling the temperature and atmospheric pressure of the substrate to appropriate values, the thin film (4) will become porous due to nucleation or self-shading effect during the formation process. The thin film (4) has a columnar structure and has uniform pores with a pore diameter of 5 to 2,000. If the pore size is less than 5, the gas permeation rate will be low and practicality will be lost.
Since the gas separation performance will deteriorate if the pore size is tested using pores, the pore diameter is controlled to be 5 to 2,000 pores. 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 (4) on the surface of the phase-separable glass layer (3) in this way by a vapor phase method, when the glass layer (3) is heated and subjected to phase-separation treatment,
As shown in Figure 3, the 0 minute phase treatment, in which decentralization occurs in the glass layer (3) and separates into a silica-rich glass phase (5) and an alkali-rich glass phase (6), is generally performed at 15 min.
The heating is carried out at 0°C to 800°C for 0°5 hours or more, and when Na weight 0-BtOs -3i O1 type glass is used as the phase-separable glass, it is carried out at 400°C to 700°C. If decentralized treatment is carried out for a short time at low temperature, the phase separation will be fine, and the longer the time at high temperature, the more phase separation will occur. Set the conditions for phase separation processing. After that, hot water at 90°C or higher or 0.01-0°IN hydrochloric acid at 60-100°C,
If elution treatment is performed using sulfuric acid, nitric acid, etc., the alkali-rich glass phase (6) will be eluted, leaving the FII film (4) formed by the gas phase method on the surface, as shown in Figure 4.
A silica-rich glassy porous body (8) with a net-like pore size of 0.00 mm (η) results. If the pore size is less than 10 mm, the gas permeation rate will decrease, and if it exceeds 5000 mm, the gas separation will occur. Performance decreases.

(Function) In this way, in the present invention, a thin film is formed on the surface of the glass layer (3) which is flat and smooth and has a certain degree of strength and is suitable for forming a thin film by a vapor phase method, so that the pore size is 5 to 5.
A thin film (4) with uniform and minute pores of 2,000 pores can be stably formed. Moreover, by performing phase separation treatment and elution treatment of the glass phase after mH formation, the thin film (4) can be stably formed.
) while leaving the glass layer (3) on the surface.
The surface of the vitreous porous body (8) with high gas permeability can be made into a silica-rich porous body (8) with high gas permeability having 0.000 reticular pores (7). It is possible to stably produce a separation membrane in which a thin film (4) with uniform and minute pores is formed, and by adjusting the thin film formation conditions by the vapor phase method and the phase separation treatment conditions of the glass layer (3). Unlike conventional organic polymer membranes, the separation membrane of the present invention is made of glass, ceramic, or metal, so it has excellent heat resistance and resistance. It has excellent chemical resistance and durability, and does not have cranks like the multilayered porous bodies obtained by impregnating conventional ceramic sintered bodies with aluminum Alcolade, etc., and drying and firing after hydrolysis. , which is suitable for efficient gas separation.

(Example) Example I N a to Btus - Si Ox system phase-separable glass was melted to form a flat plate with a thickness of 1 fi, and this was treated in a reaction tube by a gas phase chemical reaction method. A thin film made of Altos and having a thickness of 10 μm and having pores having an average pore diameter of 200 μm was formed on the surface of the flat plate. Raw material gas is AlCl5
, HgO, and the carrier gas is Ar%O! The reaction temperature was 900°C. After that, phase separation treatment was performed at 500℃ for 12 hours, and elution treatment was performed with 0.1N hydrochloric acid at 90℃ to form a silica-rich glass layer with an average pore diameter of 200℃.
A glassy porous body with 0 net-like pores was obtained. As a result, a film with a thickness of 10 μm was formed on the surface of the glassy porous body by the vapor phase method.
A separation membrane was obtained in which a thin film was formed.

Example 2 Na! A 1 m thick flat plate is formed by melting OBtus-SiOs type phase-separable glass, and this is coated in a reaction tube with a vacuum evaporation method to form a membrane having pores with an average pore size of 50 pores on the surface of the flat plate. A thin film of At1o3 having a thickness of 2 μm was formed. The evaporation source is AI, the atmosphere is 0 snow, and the pressure is 1G-'tor.
r, and the temperature of the flat plate made of phase-separable glass is 40
When the temperature was maintained at 0°C, phase separation proceeded simultaneously with the formation of a thin film. After cooling, 90°C, 0. The glass layer was subjected to elution treatment with IN hydrochloric acid to form a glassy porous body having network pores with an average pore diameter of 1,000 pores and consisting of silica. 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 have an average pore diameter of 1 μm and a thickness of 1 μm.
Na to on a flat plate made of Tsuru's porous ceramic material.
A phase-separable glass of Os-S i Ox system was applied to a thickness of 300μ, and after heating and melting, it was sputtered in a reaction tube to form an average pore size of 100 on the surface of the phase-separable glass. A with a film thickness of 0.1 μ with pores of
A thin film of IN was formed. The cathode material is AI, Ar5X1
The discharge was carried out in an atmosphere of 0-" torr and Nz2
℃ 12 hours of phase separation treatment, and after cooling 90'C1O,l
Elution treatment was carried out with N hydrochloric acid, and the glass layer on the alumina porous body was made into a 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 001 μm was formed on the surface of a glassy porous body by a vapor phase method.

In addition to the separation membranes of Examples 1 to 3 above, as a comparative example, glass was subjected to phase separation treatment to create a separation membrane consisting only of glass with a thickness of 1 fl and an average pore diameter of 50 mm, and a flow-through gas separation device was constructed. A separation test was conducted on a mixed gas containing 50% (by volume) Hg and 150% N.

Supply side pressure 5.0 yen/-1 Outlet side pressure 1 kg/cd,
As a result of testing at a 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 glass layer with a smooth surface and a certain degree of strength that can be phase separated. After forming a thin film with pores, the glass layer is decentralized and eluted to make the glass layer a porous material with high gas and gas permeability while leaving the thin film, making it suitable for gas separation. It is possible to stably obtain a separation membrane consisting of a thin film with pores and a porous body with high gas permeability.The separation membrane of the present invention has uniformity of pores, heat resistance, and chemical resistance. It has excellent durability and 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 for practical use. Furthermore, the separation membrane of the present invention can be manufactured to any thickness and pore size, and is crack-free, making it suitable for particularly efficient gas separation. In this way, the present invention improves H, recovery % CI from by-product gas of steel works.
Mixing ratio adjustment of synthesis gas (Co-Hz) in chemistry,
In addition to being useful in the field of gas separation, such as concentrating He from natural gas, the separation membrane of the present invention can also be used in other applications such as filtration of aqueous solutions and organic solvents, filtration of yeast and molds, and filtration of bacteria and viruses. In addition to the fields 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, we also apply desalination and purification of seawater, salt water, etc. It can also be effectively used in the field of reverse osmosis, such as the production of water and sterile water. Therefore, the present invention eliminates the problems of conventional separation membranes of this type and greatly contributes to the development of industry.

[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. (2): Ceramic porous body, (4) Bithin film, +71:
N4-like pores (...porous layer of the Nigarasu Prize. Figure 4)

Claims (1)

[Claims] 1. The pore size obtained by phase separation treatment of glass is 10 to 500.
A metallic or ceramic thin film (4) produced from a gas phase and having pores of 5 to 2000 Å in diameter was formed on the surface of a glassy porous body (8) having 0 Å network pores (7). A separation membrane characterized by: 2. Glassy porous body (8) is ceramic porous body (2)
2. The separation membrane according to claim 1, wherein the separation membrane is formed to have a thickness of 10 to 500 microns. 3. The separation membrane according to claim 1 or 2, wherein the thin film (4) has a thickness of 10 Å to 100 μ. 4. On the surface of the phase-separable glass layer, 5 to 2
Forming a metal or ceramic thin film having pores with a pore diameter of 000 Å and subjecting the glass layer to phase separation treatment,
A method for producing a separation membrane, comprising the steps of: thereafter subjecting the phase-separated glass layer to an elution treatment to form the glass layer into a glassy porous body having network pores of 10 to 5000 Å.