JP3530807B2 - Manufacturing method of mixture separation membrane device and mixture separation membrane device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a mixture separation membrane device and a mixture separation membrane device comprising a ZSM-5 type zeolite membrane formed by crystal growth on the surface of a porous support substrate.

[0002]

2. Description of the Related Art A method for separating a liquid mixture by a pervaporation method using a non-porous polymer membrane is disclosed in US Pat. No. 2,953,502. This separation method is suitable for separating small components contained in the organic liquid. For example, it is suitable for separating alcohol from the alcohol fermentation tank and recovering organic substances in wastewater.

Conventionally, as a membrane used in such a separation method, a membrane made of polydimethylsiloxane, polytrimethylsilylpropyne or a copolymer thereof is known. However, when the organic liquid mixture is separated by the pervaporation method using such a membrane, the permeation performance of the membrane is low and it cannot be said that it is an efficient separation means. In addition, these polymer membranes are destroyed even if impurities such as acid or alkali are contained in the organic liquid to be recovered and / or purified even in a trace amount. .

Recently, a water-repellent zeolite membrane having high selective permeability and chemical resistance has been developed, and practical studies have begun to be actively conducted. In particular, the ZSM-5 type zeolite membrane formed on the surface of the porous support substrate by the hydrothermal synthesis method is inexpensive and has high selective permeability, and is said to be applicable to recycling of unused bio-based waste. ing.

As a prior art document relating to a mixture separation membrane device comprising such a ZSM-5 type zeolite membrane on the surface of a porous support substrate and a method for producing the same, Japanese Patent Laid-Open No. 8-25
7302 publication is mentioned. A mixture separation membrane device provided with a ZSM-5 type zeolite membrane disclosed in this document is obtained by immersing a tubular porous support substrate in a mother liquor for forming a ZSM-5 type zeolite membrane and heating the mother liquor. ZSM-5 type zeolite crystals were synthesized by a hydrothermal synthesis method, and the crystals were grown to form ZSM- on the surface of the porous support substrate.
It is produced by forming a type 5 zeolite membrane.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
A mixture separation membrane device comprising a ZSM-5 type zeolite membrane disclosed in Japanese Patent Publication No. 302-302 is a method for producing the same, in which a mother liquor for forming a ZSM-5 type zeolite membrane contains sodium based on sodium hydroxide as a component. Since the aluminosilicate gel containing is used, there is an advantage that a film having no defects such as pinholes can be produced with good reproducibility due to the presence of the sodium. However, as a result of sodium ions remaining in the film-formed ZSM-5 type zeolite membrane, the ZSM-5 type zeolite membrane becomes hydrophilic due to the presence of the sodium ions, and the separation performance is reduced accordingly, and the mixture Some measures have been desired to further improve the separation performance of the separation membrane device.

An object of the present invention is to provide a method for producing a mixture separation membrane device which can further improve the separation performance and a mixture separation membrane device which further improves the separation performance.

[0008]

In order to achieve the above object, in the method for producing a mixture separation membrane device according to the invention of claim 1, a ZSM-5 type zeolite crystal is formed on the surface of a porous support substrate. A step of allowing a powdery seed crystal to grow, and ZSM-5 containing no sodium in the components
Of the ZSM-5 type zeolite by immersing the porous supporting substrate in a mother liquor for forming a zeolite-type zeolite membrane and heating for a predetermined time to grow a crystal of ZSM-5 type zeolite with the seed crystal as a nucleus on the surface of the porous supporting substrate. -5 type zeolite membrane forming step is included.

According to the present invention, since the mother liquor for forming the ZSM-5 type zeolite membrane does not contain sodium as a component, ZSM-5 formed on the surface of the porous support substrate.
Unlike the conventional method, sodium ions do not remain in the type zeolite membrane. That is, crystals of ZSM-5 type zeolite grow on the surface of the porous support substrate with the seed crystals as nuclei, and a film of ZSM-5 type zeolite is formed on the surface of the porous support substrate by the crystal growth. However, since this crystal growth proceeds by feeding the components in the mother liquor as nutrients, ZS containing no sodium ions.
An M-5 type zeolite membrane is obtained. Therefore, the membrane is not hydrophilic and the separation performance of the mixture separation membrane device can be further improved.

Moreover, seed crystals, that is, powdery seed crystals capable of growing ZSM-5 zeolite crystals are attached to the surface of the porous supporting substrate immersed in the mother liquor for forming the ZSM-5 zeolite film. Therefore, it is possible to form a ZSM-5 type zeolite membrane without defects such as pinholes even when sodium is not contained as a component in the mother liquor as in the conventional case.

Further, since the seed crystal is preliminarily attached to the surface of the porous supporting substrate, the required amount of the template agent can be reduced.

In the method for producing the mixture separation membrane device, in the step of forming the ZSM-5 type zeolite membrane on the surface of the porous supporting substrate, the product is finally calcined. This firing is performed for the purpose of removing unreacted substances that cause defects such as pinholes, and firing conditions such as firing temperature and firing time are determined from the viewpoint of achieving this purpose. Generally, 20 ~ above 400 ℃
It is baked for 40 hours, and the heating rate at that time is about 50 ° C./h.

Examples of the material of the porous supporting substrate include, but are not limited to, alumina porous membrane, metal, organic polymer, inorganic polymer and ceramics. The shape of the porous supporting substrate is such that the mixture separation membrane device used in the pervaporation method or vaporization method has an outer diameter of about 10 mm and a length of 20 cm to 100.
cm pipe with a thickness of 0.2 mm to several mm
Or outer diameter 30mm-100mm, length 20c
Inner diameter of 2 mm to 12 in a cylinder of m to 100 cm and above
It is preferable to open a large number or a lotus root shape in the axial direction of about mm.

The average pore diameter of the porous supporting substrate is 0.05.
μm to 10 μm is preferable. If the lower limit of 0.05 μm is exceeded, the permeation rate will be low, making it impractical, and the upper limit of 10 μm.
If it exceeds, the selectivity decreases. Examples of preferable porous support substrates include those having an average pore diameter of 0.1 μm to 2 μm and a porosity of about 30% to 50%.

Next, regarding the ZSM-5 type zeolite, for example, “Science and Application of Zeolites” edited by Hiroo Tominaga, published by Kodansha Scientific Co., Ltd. January 1987 2.
2 Basic structural units and classification of zeolites Page 17 "Table 2.
2 It is a substance that has been known from the past, such as "a typical molecular sieve zeolite". When the activity of the ZSM-5 type zeolite decreases, it can be recovered by firing.

The seed crystal preliminarily attached to the surface of the porous support substrate is formed into a film by growing a crystal of ZSM-5 type zeolite with the seed crystal as a nucleus in relation to the components in the mother liquor. However, it is not limited to a specific type. For example, a nano-sized colloidal silicalite suspension or a size of 4 μm to 20 μm
Examples include silicalite crystal powder to a degree. An example of the former suspension is TEOS (tetraethoxysilane) as a starting material and TPAOH as a template agent.
(Tetrapropylammonium hydroxide solution), sodium hydroxide solution and distilled water can be used for hydrothermal synthesis. Its composition is SiO ₂ : TPAOH:
_{NaOH: H 2 O = 10:} 1~3: 1~2: 50~20
It is 0 (molar composition ratio). The seed crystal is applied to the surface of the porous support substrate by immersing and coating the porous support substrate in the suspension. An example of the latter crystal powder is TEOS as a starting material and TPAO as a template agent.
It can be made by hydrothermal synthesis using H and distilled water. Its composition is SiO ₂ : TPAOH: H ₂ O =
It is 1: 0.1 to 1:50 to 200 (molar composition ratio).
The seed crystal is attached by putting the crystal powder in distilled water, making it into a slurry, and applying it to the surface of the porous supporting substrate. The former seed crystal contains sodium, but the ZSM-5 type zeolite membrane formed in the mother liquor using this sodium-containing seed crystal, and the latter seed crystal not containing sodium in the mother liquor As described in the embodiments described later, no difference in separation performance is observed between the ZSM-5 type zeolite membrane formed by the method described in 1. and the conventional ZSM-5 type zeolite membrane in which sodium ions remain. The separation performance could be improved from (Japanese Patent Laid-Open No. 8-257302). This is because the mother liquor used in the present invention does not contain sodium as a component thereof, and thus seed crystals that do not contain sodium are nucleated in the process of synthesizing and growing ZSM-5 type zeolite crystals in the mother liquor. It is presumed that this is because the synthesis and growth of the crystal proceed, and the new crystal does not synthesize and grow with the seed crystal containing sodium as a starting point.

Next, the mother liquor for forming the ZSM-5 type zeolite membrane is not limited to a particular one as long as it does not contain sodium as a component. As an example, one described in claim 2, namely, TEOS, TPAOH and H ₂ O as a template agent, in a molar composition ratio of Si
O ₂ : TPAOH: H ₂ O = 1: 0.1 to 1:80 to 5
Examples of the gel include gels adjusted to be 00. The porous supporting substrate is immersed in the mother liquor and heated for a predetermined time to grow ZSM-5 type zeolite crystals with the seed crystals as nuclei on the surface of the porous supporting substrate.
The heating at that time is performed in order to bring the temperature of the mother liquor to a temperature at which the crystal growth reaction can proceed, and the temperature is determined from that viewpoint. Specifically, the heating is performed so that the temperature of the mother liquor does not exceed the heat resistance temperature for oxidative decomposition of the template agent and is 100 ° C. or higher (claim 2). The heating time depends on the heating means used. In addition, in practice, it is preferable to heat to a temperature of about 160 ° C to 180 ° C.

According to the second aspect of the present invention, the mother liquor for forming the ZSM-5 type zeolite membrane has the above-mentioned components and compositions, and is heated by heating means so that the temperature of the mother liquor falls within the above temperature range. By heating, the crystal growth of the ZSM-5 type zeolite, which is carried out on the surface of the porous supporting substrate, can be smoothly advanced while effectively functioning the template agent. Yet, the amount of template needed is low.

The invention according to claim 3 of the present application is characterized in that a microwave is used as the heating means in the method for manufacturing a mixture separation membrane device according to claim 2. According to the present invention, since microwaves are used as the heating means, water molecules are activated in an excited state, and in this state, ZSM-5 type zeolite is synthesized and its crystals grow, Unlike merely raising the temperature of the mother liquor to the desired temperature, its synthesis reaction rate can be increased and the required film formation time can be shortened. 10 by hydrothermal method
The present inventor has confirmed that it is possible to shorten the time taken from 48 hours to about 0.25 hours to 5 hours.

The mixture separation membrane device according to the invention of claim 4 comprises a porous support substrate and a ZSM-5 type zeolite membrane formed by crystal growth on the surface of the porous support substrate. A mixture separation membrane device is provided, wherein the ZSM-5 type zeolite membrane is a membrane not containing sodium ions. here,
The term "does not contain sodium ion" is used to mean that the concentration is not limited to the literal concentration of 0, and that the range of existence as an unavoidable impurity is included.

According to the present invention, since the ZSM-5 type zeolite membrane is a membrane containing no sodium ion, it does not become hydrophilic. Therefore, since there is no factor that lowers the separation performance, the separation performance of the mixture separation membrane device can be further improved.

The mixture separation membrane device of the present invention can be used in any of the pervaporation method, the vapor permeation method and the gas separation method. ZSM of the present invention
The mixture to be separated of the -5 type zeolite membrane is not limited to a specific one, and examples thereof include a liquid mixture of water and alcohols such as methanol, ethanol and propanol, ketones such as acetone and methyl ethyl ketone,
Carbon tetrachloride, a liquid mixture of an organic solution such as a halogenated hydrocarbon such as trichlorethylene and an alcohol such as methanol, ethanol or propanol, a liquid mixture of the alcohol and an aromatic such as benzene or cyclohexane, further A liquid mixture is a mixture of two or more kinds. Further, also available for the separation of gas mixtures, for example, the separation of _{n-C 4 H 10} and the _{i-C 4 H 10} isomers of butane. Examples of liquid mixtures in which the separation membrane of the invention show particularly good selectivity include organic liquid mixtures, in particular water-alcohol mixtures such as water-ethanol mixtures and water-butanol mixtures.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the method for producing a mixture separation membrane device according to the present invention will be specifically described below. Figure 1
FIG. 3 is a graph showing an X-ray diffraction diagram of a porous mullite support substrate having a ZSM-5 type zeolite membrane formed on its surface by the production method of Embodiment 1. FIG. FIG. 2 is an SEM (scanning electron microscope) photograph of the film surface formed on the surface of the porous mullite supporting substrate by the manufacturing method of the first embodiment. FIG. 3 is a schematic configuration diagram of a performance evaluation device that measures the permeation performance of the ZSM-5 type zeolite membrane obtained by the manufacturing method of the first embodiment. FIG. 4 shows ZSM-5 formed by the method of the first embodiment.
It is a graph which shows the result of pervaporation performed about the mixture separation membrane apparatus which has a type zeolite membrane.

[Embodiment 1] Using TEOS, TPAOH as a template agent, a sodium hydroxide solution and distilled water, SiO ₂ : TPAOH: N at a molar composition ratio.
A gel adjusted to have aOH: H ₂ O = 10: 2.44: 1.7: 114 was charged into a reaction vessel, and the temperature was 100 ° C.
Hydrothermal synthesis was performed for 48 hours to prepare a template (TPAOH) -containing nano-sized colloidal silica suspension.
A tubular porous mullite support substrate (trade name PM tube manufactured by Nikkato Co., Ltd .: diameter 12 cm, length 20 cm, wall thickness 1.5 mm, pore diameter 1 μm, porosity 40%) was immersed in this colloidal silica suspension. Then, it was dried in a constant temperature bath at 70 ° C., and a seed crystal was uniformly applied to the surface of the porous supporting substrate. This seed crystal contains sodium ions due to its manufacturing method.

ZSM-5 containing no sodium in its components
The mother liquor for forming the zeolite-type zeolite membrane uses TEOS, TPAOH as a template agent, and distilled water in a molar composition ratio of SiO ₂ : TPAOH: H ₂ O = 1: 0.16.
It was adjusted to be 7: 118. The porous supporting substrate coated with the seed crystal is immersed in the film-forming gel thus prepared, and the mother liquor is heated using microwaves to 170 ° C.
The ZSM-5 type zeolite crystals were continuously synthesized and grown for 4 hours to form a ZSM-5 type zeolite membrane on the surface of the porous support substrate. Then, it baked at 400 degreeC for 30 hours. The heating rate during firing was 50 ° C./h.

The X-ray diffraction pattern of the zeolite membrane thus formed is shown in FIG. As can be seen from FIG. 1, the peak pattern is in good agreement with that of a crystal powder of a commercially available ZSM-5 type zeolite, which confirms that the film is formed of ZSM-5 type zeolite. Was done.

FIG. 2 is an SEM (scanning electron microscope) photograph of the film surface formed on the surface of the porous mullite supporting substrate by the manufacturing method of the first embodiment. The film thickness is about 3 μm to 100 μm. From this photograph, a precise ZSM-5 of about 3 μm
It was confirmed that type zeolite crystals were deposited on the surface of the porous mullite supporting substrate.

[Embodiment 2] Using TEOS, TPAOH as a template agent, and distilled water, the molar composition ratio is SiO ₂ : TPAOH: H ₂ O = 1: 0.167:
The gel adjusted to be 118 was charged into a reaction vessel, and hydrothermally synthesized at 160 ° C. to 170 ° C. for 16 hours to prepare a crystal powder containing a template (TPAOH). This crystal powder (powder diameter is 4 μm to 20 μm) and water are mixed in a slurry form, and a tubular porous mullite support substrate (product name PM tube manufactured by Nikkato Co., Ltd .: diameter 12 cm, length 20 cm, wall thickness 1.5 mm) , Pore size 1 μm, porosity 40
%) And then dried in a constant temperature bath at 70 ° C. to uniformly distribute seed crystals on the surface of the porous supporting substrate. This seed crystal does not contain sodium ions due to its manufacturing method.

ZSM-5 containing no sodium in its components
The mother liquor for forming the zeolite-type zeolite membrane uses TEOS, TPAOH as a template agent, and distilled water in a molar composition ratio of SiO ₂ : TPAOH: H ₂ O = 1: 0.16.
It was adjusted to be 7: 118. The porous supporting substrate coated with the seed crystal is immersed in the film-forming gel thus prepared, and the mother liquor is heated using microwaves to 170 ° C.
The ZSM-5 type zeolite crystals were continuously synthesized and grown for 4 hours to form a ZSM-5 type zeolite membrane on the surface of the porous support substrate. Then, it baked at 400 degreeC for 30 hours. The heating rate during firing was 50 ° C./h.

The X-ray diffraction pattern of the zeolite membrane thus formed is almost the same as that shown in FIG.
It was confirmed that it was formed of M-5 type zeolite.

[Third Embodiment] In the first embodiment, the porous supporting substrate coated with the seed crystal is immersed in the film-forming gel, and the mother liquor is heated using microwaves in the hydrothermal synthesis. A ZSM-5 type zeolite membrane was formed on the surface of the porous support substrate in the same manner as in Embodiment 1 except that the above was changed to. Hydrothermal synthesis was carried out at 170 ° C. for 16 hours.

The X-ray diffraction pattern of the zeolite membrane thus formed is almost the same as that shown in FIG.
It was confirmed that it was formed of M-5 type zeolite.

[Embodiment 4] In Embodiment 2, the porous supporting substrate coated with the seed crystal is immersed in the film-forming gel, and the mother liquor is heated using microwaves in the hydrothermal synthesis. A ZSM-5 type zeolite membrane was formed on the surface of the porous supporting substrate in the same manner as in Embodiment 2 except that the above was changed to. Hydrothermal synthesis was carried out at 170 ° C. for 16 hours.

The X-ray diffraction pattern of the zeolite membrane thus formed is almost the same as that shown in FIG.
It was confirmed that it was formed of M-5 type zeolite.

[Evaluation of membrane performance] Next, the first embodiment
The pervaporation performance was measured by the mixture separation membrane device having the ZSM-5 type zeolite membrane obtained by. First, as shown in FIG. 3, the mixture separation membrane device 1 having a ZSM-5 type zeolite membrane is attached to the separation cell 2 of the performance measuring device. The effective membrane area was 47 cm ² .

The separation cell 2 comprises a permeate chamber 4 and permeate chambers 5 arranged on both sides thereof, and the permeate chamber 4 and the permeate chamber 5 are separated by the mixture separation membrane device 1. In addition, it is placed in the constant temperature bath 6. A supply pipe 8 for the permeated liquid 7 is connected to one end of the permeated liquid chamber 4,
A discharge pipe 9 is connected to the other end. The supply pipe 8
A permeated liquid storage tank 11 is attached to the exhaust pipe 9 via a pump 10, and an exhaust liquid reservoir 13 is attached to the exhaust pipe 9 via a heat exchanger 12. The separated liquid that has permeated the mixture separation membrane device 1 was taken out in a vapor phase by a decompression means, cooled, solidified, and collected. That is, the pipe 14 for taking out the separated liquid connected to the permeate chamber 5 is connected to the pipe 14A and the pipe 14
B, and are connected to the vacuum pump 16 via cooling traps 15A and 15B, respectively. Reference numeral 17 indicates a nitrogen gas discharge pipe, and reference numeral 18 indicates a switching cock.

In the performance test, the liquid to be separated (liquid mixture) was
It was supplied at 2 to ³⁰ cm ³ / min, and the internal pressure of the permeate chamber 5 was maintained at a vacuum degree of 0.1 Torr by the vacuum pump 16 and the cooling trap 15A or 15B. The permeability of the membrane is
Total permeation amount per unit area and unit time Q (kg / m
² h) and the separation coefficient α defined by the following formula. α = (P _A / P _B ) / (F _A / F _B ) In the above formula, F _A and F _B are the concentrations (wt%) of the liquids A and B in the supply liquid, respectively, and P _A and P _B is the concentration (wt%) of the liquids A and B in the permeated liquid, respectively.

Evaluation test results conducted on a mixture separation membrane device having a ZSM-5 type zeolite membrane formed by the method of Embodiment 1 using an aqueous solution of ethyl alcohol (A is ethyl alcohol and B is water) as the liquid to be separated. Is shown in Table 1.
For ease of comparison, the results of a mixture separation membrane device (Japanese Patent Laid-Open No. 8-257302) comprising a conventional ZSM-5 type zeolite membrane in which sodium ions remain are also shown.

[0039]

[Table 1] FIG. 4 is a graph showing the results of pervaporation performed on a mixture separation membrane device having a ZSM-5 type zeolite membrane formed by the method of the first embodiment.

From the above results, ZSM-5 according to the present invention
It can be seen that the mixture separation membrane device provided with the type zeolite membrane has improved membrane permeation performance in terms of both the total permeation amount Q and the separation coefficient α as compared with the conventional device.

[0041]

EFFECTS OF THE INVENTION According to the present invention, since the mother liquor for forming the ZSM-5 type zeolite membrane does not contain sodium as a component, the ZSM-type membrane formed on the surface of the porous support substrate is used.
Sodium ions do not remain in the type 5 zeolite membrane as in the conventional case. Therefore, the membrane is not hydrophilic and the separation performance of the mixture separation membrane device can be further improved.

Moreover, seed crystals, that is, powdery seed crystals capable of growing ZSM-5 type zeolite crystals are attached to the surface of the porous supporting substrate immersed in the mother liquor for forming the ZSM-5 type zeolite film. Therefore, it is possible to form a ZSM-5 type zeolite membrane without defects such as pinholes even when sodium is not contained as a component in the mother liquor as in the conventional case.

[Brief description of drawings]

FIG. 1 is a graph showing an X-ray diffraction diagram of a porous mullite support substrate having a ZSM-5 type zeolite membrane formed on its surface by the production method of the first embodiment.

FIG. 2 is an SEM (scanning electron microscope) of a film surface formed on the surface of a porous mullite supporting substrate by the manufacturing method of the first embodiment.
It is a photograph.

FIG. 3 is a ZSM-obtained by the manufacturing method of the first embodiment.
It is a schematic block diagram of the performance evaluation apparatus which measured the permeation performance of a 5 type zeolite membrane.

FIG. 4 is a graph showing the results of pervaporation performed on a mixture separation membrane device having a ZSM-5 type zeolite membrane formed by the method of the first embodiment.

[Explanation of symbols]

1 Mixture separation membrane device equipped with ZSM-5 type zeolite membrane 2 Separation cell significance

Continuation of the front page (56) Reference JP 2000-26115 (JP, A) JP 7-109116 (JP, A) JP 2000-225327 (JP, A) (58) Fields investigated (Int.Cl) . ⁷ , DB name) B01D 61/36-71/02

Claims (4)

(57) [Claims] 1. A step of allowing a powdery seed crystal capable of growing ZSM-5 type zeolite crystals to be present on the surface of a porous supporting substrate, and a ZSM-5 type zeolite membrane for forming a ZSM-5 type zeolite film containing no sodium in the components. The porous support substrate is immersed in a mother liquor and heated for a predetermined time to grow ZSM-5 type zeolite crystals on the surface of the porous support substrate with the seed crystals as nuclei.
And a step of forming a membrane of SM-5 type zeolite, the method for producing a mixture separation membrane device. 2. The mother liquor according to claim 1, wherein the mother liquor is TEO.
S (tetraethoxysilane), TPAOH (tetrapropylammonium hydroxide solution) as a template agent
And H2 O, in a molar _{ratio, SiO 2: TPAOH: H 2} O = 1: 0.1~1: 80
The heating is performed so that the temperature of the mother liquor does not exceed the heat resistance temperature for oxidative decomposition of the template agent and is 100 ° C. or higher by a heating unit. And a method for manufacturing a mixture separation membrane device. 3. The method for manufacturing a mixture separation membrane device according to claim 2, wherein a microwave is used as the heating means. 4. A mixture separation membrane device comprising a porous support substrate and a ZSM-5 type zeolite membrane formed by crystal growth on the surface of said porous support substrate, said ZSM-5 type The mixture separation membrane device, wherein the zeolite membrane is a membrane that does not contain sodium ions.