JP2006176399A - Phillipsite-type-zeolite membrane and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phillipsite (PHI)-zeolite membrane formed on a porous base material such as alumina, and to provide its manufacturing method and its uses. <P>SOLUTION: The zeolite membrane, which is formed on a supporting base material, has a structure of a phillipsite (PHI) membrane formed on the supporting base material, and has characteristics of high hydrophilicity and high acid resistance. The manufacturing method and the uses, such as a separation membrane, of the zeolite membrane are provided. By the manufacturing method, a new phillipsite membrane can be synthesized, so that a PHI membrane preferably usable for industrial uses as a membrane reactor or a catalyst membrane, which performs not only separation and concentration of gas and liquid but catalytic reactions simultaneously, is synthesized and provided. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a zeolite membrane, and more particularly, a Philipsite (PHI: written in English three letters) membrane in which the zeolite membrane is formed on a support. The present invention relates to a use of a Philippine type zeolite membrane characterized by having acid resistance characteristics, a synthesis method thereof, a separation membrane and the like. In particular, the present invention provides a new technology and a new product related to a novel PHI film that can be suitably used in a system that requires acid resistance.

  Zeolites have regularly arranged micropores, and are generally used in various fields because many heat resistant and chemically stable materials can be obtained. This zeolite is an aluminosilicate in which a part of Si is substituted with Al, has a pore of molecular order (about 3-10Å), and has a stereoselective adsorption action. It functions as a sieve (molecular sieve). In addition to dozens of naturally occurring zeolites, more than 150 types of zeolites have been synthesized so far and are widely used in fields such as solid acid catalysts, separated adsorbents, and ion exchangers.

  Since this zeolite is poor in plasticity, when it is formed into a film, in most cases, the zeolite film is synthesized on a substrate by a hydrothermal synthesis method. That is, a large amount of water and an organic crystallization regulator such as an aluminum source, a silica source, an alkali metal, and amines are appropriately formulated so as to have a desired zeolite composition, and they are sealed in a pressure vessel such as an autoclave. A zeolite membrane is synthesized on these substrates by heating in the presence of a porous substrate or tube such as alumina or mullite.

  So far, for example, zeolite membranes such as MFI, MEL, LTA, ANA, CHA, FAU, SOD, MOR, ERI, BEA, LTL, DDR have been synthesized, and the properties of each zeolite (for example, pore size / affinity) The separation target is appropriately selected. In addition, the prior literature discloses a method of synthesizing a zeolite membrane having no defect by hydrothermal synthesis after applying a zeolite seed crystal (Patent Document 1). The disclosed zeolite membrane is disclosed to be used for separation / concentration from a gas or liquid mixture (Patent Document 2).

  As an example of practical use as a separation method instead of the distillation method due to the improvement of zeolite membrane synthesis technology in recent years, there is a method for concentrating alcohol by selective permeation of water from an aqueous alcohol solution utilizing the hydrophilicity of A-type zeolite. Yes (Patent Document 3). This type A zeolite is inferior in acid resistance to other high silica type zeolites (its structure is destroyed when it comes into contact with an acid), so it is difficult to use it for separation of an acidic mixture from water. There was a problem that there was. Therefore, separation / concentration using a T-type zeolite (Patent Document 4), a high silica type zeolite membrane such as mordenite and silicalite has been proposed.

JP 2003-159518 A JP 2003-144871 A Japanese Patent No. 3431973 JP 2000-042387 A

  Under such circumstances, the present inventors have not yet reported PHI (Phillipsite: having an oxygen 8-membered ring structure, 3.8 × 3.8 mm: [100], 3. As a result of diligent research to develop a PHI film, focusing on the 0 × 4.3 mm [010] and 3.3 × 3.2 mm [001] pore diameter), the PHI film was manufactured on the substrate. We succeeded in forming a film, and completed the present invention. An object of the present invention is to synthesize and provide a hydrophilic PHI zeolite membrane having high acid resistance, which has not been synthesized conventionally.

  Further, in the synthesis of the PHI zeolite membrane, the affinity and structure of the PHI zeolite membrane are different by arbitrarily changing the kind of zeolite to be formed on the inner and outer sides of porous tube tubes such as alumina or on the upper and lower sides, or on the upper and lower sides. The object is to synthesize and provide a zeolite membrane. Furthermore, an object of the present invention is to provide a zeolite membrane that can be used as a catalyst membrane capable of performing a reaction simultaneously with separation / concentration from a gas or liquid mixture, and a synthesis method thereof.

  The present invention for solving the above-mentioned problems is a Philipsite (PHI) membrane having a structure formed on a support in a zeolite membrane formed on a support substrate, and has a high hydrophilicity and a high acid resistance. A zeolite membrane characterized by having a property of In the present zeolite membrane, (1) the substrate is a metal and / or metal oxide substrate, (2) the substrate is an alumina, mullite, zirconia, or SUS porous substrate, 3) It is a preferable aspect that the PHI membrane has non-permeability that does not transmit air. The present invention also provides a separation membrane comprising the above highly hydrophilic and highly acid-resistant zeolite membrane. The separation membrane is preferably a hydrophilic zeolite membrane for dehydration. The present invention also provides a membrane reactor capable of simultaneously performing separation and reaction, characterized by comprising the above-mentioned highly hydrophilic and highly acid-resistant zeolite membrane.

  In addition, the present invention provides a PHI zeolite membrane on a support substrate by using a raw material solution having a PHI composition and converting it to zeolite by a hydrothermal synthesis method or converting aluminosilicate gel to zeolite by steam treatment. Is a method for producing a zeolite membrane, characterized by comprising: In addition, the present invention is a method in which a seed crystal prepared by using a raw material solution having a PHI composition is applied to a porous support substrate and then converted into zeolite by a hydrothermal synthesis method or an aluminosilicate gel is subjected to steam treatment. A method for producing a zeolite membrane, characterized in that a PHI zeolite membrane is formed on a porous support base material by a technique for conversion to zeolite. This method includes (1) secondary growth of seed crystals to form a continuous film, (2) surface treatment of the film after synthesis of the PHI film, and (3) surface treatment of the film by alkaline aqueous solution treatment. It is preferable to remove PHI crystals, amorphous gel, and / or other crystal phases that are excessively present on the film surface by performing polishing treatment or ultrasonic treatment.

Next, the present invention will be described in more detail.
As a result of intensive studies on a PHI zeolite membrane synthesis method suitable for the above-mentioned purpose, the present inventors previously synthesized a hydrothermal synthesis on a porous support substrate (sometimes referred to as a porous support or a support). The PHI crystal synthesized by the method is applied as a seed crystal, then transferred to the autoclave together with the porous support, and the seed crystal on the porous support is secondarily grown by the hydrothermal synthesis method. Succeeded in obtaining a membrane. That is, the present invention provides a zeolite membrane in which a membrane having a PHI structure is formed on a porous support.

  Next, a preferred embodiment of the present invention will be described. In the present invention, the description of a numerical range includes not only the values at both ends but also any arbitrary intermediate value included in the range. In the present invention, as the porous support substrate, for example, a porous support substrate made of a metal or an alloy represented by alumina, mullite, zirconia, stainless steel, and aluminum is exemplified. Specifically, for example, Examples thereof include an anodized film porous support and a support having the same or similar characteristics. The form is preferably a porous material having an average pore diameter of 0.1 to 10 microns, for example, a porous support such as a tubular shape, a flat plate shape, a disk shape, or a square plate shape. However, the present invention is not limited to these, and any porous and shaped support can be used. Examples of the method for cleaning the surface of the support include water washing and ultrasonic cleaning. Preferably, the method of cleaning the surface of the support by ultrasonic cleaning with water for 1 to 10 minutes is exemplified. The

  In the present invention, a zeolite is formed on the porous support by the hydrothermal synthesis method. At that time, after rubbing the seed crystal of PHI (or faujasite, etc.) on the porous support, the seed crystal is secondarily grown by hydrothermal synthesis or steam treatment to form a strong continuous film. Alternatively, a film in which PHI crystals are arranged on the surface of the support is used. For this hydrothermal synthesis, a suitable vessel, for example, a pressure vessel is used.

In the present invention, a raw material solution having a PHI composition is used as a PHI film synthesis condition. Using water and potassium hydroxide or sodium hydroxide, alumina, colloidal silica, etc. as starting materials, 0.5-3Na ₂ O (or K ₂ O): Al ₂ O ₃ : 2-10 SiO ₂ : 20- The starting material is prepared so as to have a molar composition of 300 H ₂ O (preferably 2-2.5Na ₂ O (or K ₂ O): Al ₂ O ₃ : 4-5SiO ₂ : 80-100H ₂ O). .

  As the alumina source, any suitable alumina raw material such as commercially available activated alumina, boehmite, aluminum chloride, or sodium aluminate can be used as appropriate. As the silica source, any suitable silica raw material such as colloidal silica, water glass, commercially available powdered silica, fumed silica, and alkoxide can be used as appropriate. As the alkali source, KOH, NaOH or the like can be used. This starting material is transferred into a pressure vessel such as an autoclave and hydrothermally synthesized at 80 to 200 ° C. for 3 hours or longer, preferably 100 to 120 ° C. for 5 to 7 days, and 150 to 200 ° C. for 4 to 12 hours. Thus, a PHI crystal can be obtained.

In the present invention, as described above, the PHI crystal is applied as a seed crystal to the porous support substrate. Here, the coating is applied to the outer surface by rubbing and / or dispersing in water on the outer surface by dip coating or the like. It means applying and equivalent methods. Then, in a solution adjusted to a molar composition of 2-2.5K ₂ O (or Na ₂ O): Al ₂ O ₃ : 2-4SiO ₂ : 80-100H ₂ O, 150 to 200 ° C. for 3 to 20 hours By performing hydrothermal synthesis treatment, the seed crystal is secondarily grown to form a continuous film having a thickness of 2 to 100 μm, preferably about 5 to 50 μm.

PHI has an oxygen 8-membered ring due to its skeleton structure (3.8 × 3.8 ×: [100], 3.0 × 4.3 × [010], 3.3 × 3.2Å [001]: Atlas of Zeolite Framework Types, IZA, Ch. Baerlocher, WMMeier, DHOlson, ELSEVIER), Si / Al ratio is around 1.5 and is hydrophilic. Since the PHI membrane of the present invention has a three-dimensional pore structure and a relatively small pore diameter, it can be suitably used for the separation of low molecular gases such as CO ₂ and CH ₄ . Since the PHI membrane is a hydrophilic membrane from the Si / Al ratio, it can be applied to water / alcohol separation, and its chemical resistance is superior to that of LTA and FAU type zeolites. Application to separation processes such as is possible. The philipsite-type zeolite membrane of the present invention can be applied to high-performance and highly selective liquid and gas separation membranes, and can be used particularly as an acid-resistant dehydration membrane. Moreover, this PHI membrane can be used as a catalyst membrane, a membrane reactor, etc. that can perform separation and reaction simultaneously. The PHI film of the present invention has an advantage that it can be suitably used particularly in a system that requires acid resistance.

  In the present invention, after the synthesis of the PHI film, the surface treatment of the film is performed, so that PHI crystals, amorphous gel portions, and / or other crystal phases (for example, chabasite, mordenite, etc.) that are excessively present on the film surface are present. ) Is preferably removed. In this case, examples of the surface treatment include, but are not limited to, for example, a method using an alkaline aqueous solution such as NaOH, a polishing method using an appropriate abrasive or means, a method using ultrasonic waves, and the like. The membrane can be surface treated by any method and means. By the surface treatment, the separation performance of the membrane can be improved.

The present invention has the following effects.
(1) It is possible to provide a hydrophilic PHI zeolite membrane having a high acid resistance property by synthesizing a PHI membrane that has not been reported so far on a porous support.
(2) A method for synthesizing a hydrophilic zeolite membrane having high acid resistance can be provided.
(3) The PHI zeolite membrane of the present invention can be used as, for example, an acid-resistant dehydration membrane, a separation membrane, a membrane reactor capable of performing separation and reaction simultaneously, and a catalyst membrane.
(4) It is possible to provide a hydrophilic PHI zeolite membrane having a high acid resistance characteristic that has not been known so far.
(5) The PHI zeolite membrane of the present invention has high water separation performance and can be suitably used as a separation membrane under acidic conditions.
(6) By using a separation means using a PHI zeolite membrane in combination with the dehydration purification process and the distillation process, the cost of the heat source and equipment can be reduced.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.

In this example, PHI seed crystals were synthesized and secondary grown. To 99.0 g of ion-exchanged water, 1.53 g of NaOH (manufactured by Wako Pure Chemical Industries, Ltd.) was added and completely dissolved. Further, 1.90 g of KOH (manufactured by Wako Pure Chemical Industries, Ltd.) was added to this solution and stirred until it was completely dissolved. Next, 12.6 g of sodium aluminate (manufactured by Kanto Chemical Co., Inc.) was added thereto and stirred until it was completely dissolved. This solution, Cataloid SI-30 (Shokubai Kasei Co., Ltd., colloidal _{silica, SiO 2: 30wt%, H} 2 O: 70wt%) was obtained gradually added to a homogeneous gel solution 67.0 g.

  The gel solution was stirred at room temperature for about 30 minutes, then transferred to an autoclave (inner volume 200 mL) with a Teflon (registered trademark) inner cylinder, and hydrothermally treated at 100 ° C. for 7 days. After the hydrothermal treatment, the product in the autoclave was filtered and washed with ion-exchanged water until the pH reached about 7. The product was dried at 100 ° C. for 24 hours and then subjected to powder X-ray diffraction. As a result, the diffraction pattern of PHI (Edited by Collection of Simulated XRD Powder Patterns for Zeolites, MMJ Treacy and JB Higgins, IZA, ISBN 044507027, ELSEVIER p230, 231 (2001)).

Next, the PHI seed crystal thus obtained was ground in a mortar for about 1 to 2 minutes, and then mullite tube (manufactured by Nikkato Co., Ltd., PM tube, Al ₂ O ₃ = 65%, SiO ₂ = 33). %, Average pore diameter 1.8 microns, bulk density 1.70 g / cc, porosity 44.7%, outer diameter 6 mm, inner diameter 3 mm, length 80 mm). After the application, the mullite tube was fixed in a Teflon (registered trademark) jig in a SUS autoclave (internal volume 120 cc) and installed in the vertical direction. Si / Al = 2 mole prepared by co-precipitation with water and washing aluminum chloride hexahydrate (Nacalai) with water glass (Koso Chemical, No. 3 SiO ₂ 28%, Na ₂ O 9-10%) A solution prepared by mixing the hydrated oxide prepared in a ratio with a NaOH aqueous solution so as to have a molar composition of 2.5Na ₂ O: Al ₂ O ₃ : 4SiO ₂ : 80H ₂ O was transferred into this autoclave, and 200 ° C. And left for 3 hours in a warm air oven for hydrothermal treatment. Note that both ends of the mullite tube were closed with Teflon (registered trademark) tape in order to cover only the outside of the mullite tube with the lip site.

  As a method for applying the seed crystal, the dry PHI seed crystal may be rubbed with paper such as Kimwipe or various non-woven fabrics, or rubbed with bare hands. Alternatively, a dip-coat may be applied to the outer surface of the mullite tube using a suspension in which a PHI seed crystal is placed in a solution such as water. After performing the above hydrothermal treatment twice while changing the direction of tube fixation, the autoclave was cooled with water, and then the mullite tube was taken out and thoroughly washed with water. Next, after drying at 100 degreeC for 24 hours, it dried at 60 degreeC for 24 hours. The PHI membrane synthesized in this way was sealed at one end with a toll seal (manufactured by Niraco Co., Ltd.), air was fed from the other side at a pressure of 0.2 MPa, the mullite tube was immersed in water, When a leak test using air was performed, air did not permeate through the dried film. It was also confirmed that PHI crystals were formed at the bottom in the autoclave after the hydrothermal treatment.

Hereinafter, the same reagents as used in Example 1 were used unless otherwise specified. While stirring an aqueous solution of aluminum chloride hexahydrate (Nacalai), water glass (Koso Chemical, No. 3, SiO ₂ 28%, Na ₂ O 9-10%) was gradually added thereto, and Si / Al = 2 After mixing at a molar ratio, ammonia was added with stirring, and the resulting precipitate was filtered / washed to prepare a hydrous oxide. A hydrous oxide prepared to a molar ratio of Si / Al = 2 is mixed with a NaOH aqueous solution so as to have a molar composition of 2.5Na ₂ O: Al ₂ O ₃ : 4SiO ₂ : 83H ₂ O to obtain a uniform gel solution. Obtained.

  The gel solution was stirred at room temperature for about 30 minutes, then transferred to an autoclave (internal volume 200 mL) with a Teflon (registered trademark) inner cylinder, and hydrothermally treated at 200 ° C. for 4 hours. After the hydrothermal treatment, the product in the autoclave was filtered and washed with ion-exchanged water until the pH reached about 7. The product was dried at 60 ° C. for 24 hours and then subjected to powder X-ray diffraction. As a result, the diffraction pattern of PHI (Edited by Collection of Simulated XRD Powder Patterns for Zeolites, MMJTreacy and JBHiggins, IZA, ISBN 044507027, ELSEVIER p230, 231 (2001)).

  Next, after the PHI seed crystals thus obtained were rubbed into a mullite tube, the solution prepared in the same manner as that used for seed crystal synthesis was used for 3 hours and a half in the same manner as in Example 1. Heat treatment was performed. After the hydrothermal treatment, in the same manner as in Example 1, the mullite tube was dried, and it was confirmed that air did not permeate. Moreover, the production | generation of 20-30 micrometers thick PHI film | membrane was confirmed by the scanning electron microscope observation of the tube surface and a cross section.

  8.6 g of sodium aluminate (manufactured by Kanto Chemical Co., Inc.) was added to 70.0 g of ion-exchanged water and stirred until it was completely dissolved. Next, 6 g of NaOH (manufactured by Wako Pure Chemical Industries, Ltd.) 6 g was added to 20.0 g of ion-exchanged water and completely dissolved, added to the aqueous sodium aluminate solution and stirred until uniform. Next, 40.0 g of Cataloid SI-30 was gradually added to this solution to obtain a uniform gel solution. The gel solution was stirred at room temperature for about 30 minutes, then transferred to an autoclave (internal volume 200 mL) with a Teflon (registered trademark) inner cylinder, and hydrothermally treated at 150 ° C. for 6 hours. After the hydrothermal treatment, the product in the autoclave was filtered and washed with ion-exchanged water until the pH reached about 7.

  The product was dried at 60 ° C. for 24 hours and then subjected to powder X-ray diffraction. FAU diffraction patterns (Collection of Simulated XRD Powder Patterns for Zeolites, MMJTreacy and JBHiggins, edited by IZA, ISBN 044507027, ELSEVIER p230, 231 (2001)). Next, the FAU seed crystal thus obtained was rubbed into a mullite tube and then subjected to a hydrothermal treatment at 200 ° C. for 19 hours and a half as in Example 2. As in Example 2, a PHI film Confirmed the generation of.

  After the PHI seed crystal obtained in the same manner as in Example 2 was rubbed into a mullite tube, the hydrothermal treatment was carried out for 3 hours and a half, and further, for 2.5 hours by changing the top and bottom of the tube, as in Example 1. . As in Example 2, the formation of a PHI film was confirmed.

  The FAU seed crystal obtained in the same manner as in Example 3 was rubbed into a mullite tube and then subjected to hydrothermal treatment for 3 and a half hours in the same manner as in Example 1. As in Example 2, the formation of a PHI film was confirmed. In addition to the method described above, commercially available PHI / FAU (Faujasite) zeolite can be used as seed crystals. It was confirmed that the synthesis time can be shortened by the presence of these seed crystals in the starting material.

The separation characteristics of the PHI membrane obtained in Example 4 by the pervaporation method (PV method) were examined. As a result of measuring at 75 ° C. using an aqueous solution of 90 wt% ethanol as the feed solution, the permeation flux (Q) = 1.12 kg / m ² · h and the separation factor α (H ₂ O / EtOH) = 631. It was. From this, it became clear that the PHI membrane obtained in the present invention is a water permselective membrane. Furthermore, for the purpose of investigating chemical resistance, 0.5 g of PHI seed crystals and FAU (Faujasite, Y-type and X-type) were taken, and a 0.1N hydrochloric acid aqueous solution at 85 ° C. for 1 hour and a 10 wt% NaOH aqueous solution. When X-ray powder diffraction was measured for various zeolite samples that had been treated at room temperature for 7 days, washed with water, and dried, PHI showed no reduction in peak intensity or peak broadening compared to other zeolites. The chemical resistance was found to be excellent. Similarly, it was confirmed that the PHI film has high chemical resistance.

Using a PHI zeolite membrane, water / ethanol separation ability was evaluated by pervaporation.
(1) Experimental method For membrane preparation, a zeolite membrane was prepared by, for example, applying a seed crystal synthesized in advance to a 6 mmφ × 3-5 cm mullite tube manufactured by Nikkato, and performing secondary growth. The PV measurement was performed by stirring at a constant temperature of 40 ° C. using a 3 wt% ethanol solution as a supply liquid, and vertically immersing the formed tube. The separation factor (α = H ₂ O / EtOH) was calculated from the value analyzed by GC-TCD for the total amount of permeate trapped over several hours after stabilization of the vapor pressure on the permeate side.

(2) Results The film thickness of the zeolite membrane produced under the above conditions is 20 to 50 μm, the particle size of the membrane is around 1 to 5 μm, and according to EDX analysis of the membrane surface, the Si / Al ratio is 2. It was in the range of 5-3.0. Prior to PV measurement, the amount of water adsorbed in the equilibrium state of the zeolite powder was examined. As a result, an adsorption isotherm of type I (Langmuir type) was obtained. The water / ethanol separation factor (α value) of the membrane and the PV measurement result (Q value) of Flux (Q) were 6.6 and 0.01. The vapor pressure on the permeation side at the time of measurement was 10-15 Pa, corresponding to the Q value.

(Method for synthesizing PHI seed crystal)
The PHI seed crystal was synthesized as follows. To 99.0 g of ion-exchanged water, 1.53 g of NaOH (manufactured by Wako Pure Chemical Industries, Ltd.) was added and completely dissolved. Further, 1.90 g of KOH (manufactured by Wako Pure Chemical Industries, Ltd.) was added to this solution and stirred until it was completely dissolved. Next, 12.6 g of sodium aluminate (manufactured by Kanto Chemical Co., Inc.) was added thereto and stirred until it was completely dissolved. This solution, Cataloid SI-30 (Shokubai Kasei Co., Ltd., colloidal _{silica, SiO 2: 30wt%, H} 2 O: 70wt%) was obtained gradually added to a homogeneous gel solution 67.0 g.

  The gel solution was stirred at room temperature for about 30 minutes, then transferred to an autoclave (internal volume 200 mL) with a Teflon (registered trademark) inner cylinder, and hydrothermally treated at 100 ° C. for 7 days. After the hydrothermal treatment, the product in the autoclave was filtered and washed with ion-exchanged water until the pH reached about 7. The product was dried at 100 ° C. for 24 hours and then subjected to powder X-ray diffraction. As a result, the diffraction pattern of PHI (Edited by Collection of Simulated XRD Powder Patterns for Zeolites, MMJ Treacy and JB Higgins, IZA, ISBN 044507027, ELSEVIER p230, 231 (2001)).

(PHI seed crystal fixing method and secondary growth method)
Next, the PHI seed crystal thus obtained was ground in a mortar for about 1 to 2 minutes, and then mullite tube (manufactured by Nikkato Co., Ltd., PM tube, Al ₂ O ₃ = 65%, SiO ₂ = 33). %, Average pore diameter 1.8 microns, bulk density 1.70 g / cc, porosity 44.7%, outer diameter 6 mm, inner diameter 3 mm, length 80 mm). As a method for applying the seed crystal, the dry PHI seed crystal may be rubbed with paper such as Kimwipe or various non-woven fabrics, or rubbed with bare hands. Alternatively, a dip-coat may be applied to the outer surface of the mullite tube using a suspension in which a PHI seed crystal is placed in a solution such as water. After the application, the mullite tube was fixed in a Teflon (registered trademark) jig in a SUS autoclave (internal volume 120 cc) and installed in the vertical direction.

9.0 g of sodium aluminate (NaAlO ₂ : Nacalai Tesque, special grade) was dissolved in 50.0 g of ion-exchanged water and stirred for about 20 minutes to completely dissolve it. To this solution, an aqueous NaOH solution in which 1.0 g of NaOH (Wako Pure Chemicals, special grade) was dissolved in 10.0 g of ion-exchanged water in advance was added. Further, after adding 10.0 g of ion-exchanged water, 40.0 g of colloidal silica (Cataloid-SI-30: produced by Catalytic Chemical Co., Ltd.) is added in small portions and stirred for about 20 minutes to obtain a uniform gel. A solution was obtained.

  This gel solution was transferred into an autoclave and left to stand in a warm air oven at 150 ° C. for 6 hours for hydrothermal treatment. In order to coat PHI only on the outside of the mullite tube, both ends of the mullite tube were sealed with Teflon (registered trademark) tape. After the autoclave was cooled with water, the mullite tube was taken out and washed with ion-exchanged water. This was then dried in air for 24 hours. The PHI membrane synthesized in this way was sealed at one end with a toll seal (manufactured by Niraco Co., Ltd.), air was fed from the other side at a pressure of 0.2 MPa, the mullite tube was immersed in water, When a leak test using air was performed, air did not permeate through the dried film. In addition, when the X-ray diffraction measurement (XRD) of the outer surface of the mullite tube in which the PHI seed crystal was secondary grown was performed, a mullite diffraction pattern and a PHI diffraction pattern were obtained. It was found that it was covered with. As a result of observation of the tube surface and cross section by a scanning electron microscope (SEM), the film thickness was about 10-12 μm. FIG. 3 shows an SEM image of the surface of the PHI film grown for 6 hours.

(Evaluation of separation performance by pervaporation method)
Next, the separation characteristics of the PHI membrane thus obtained by the pervaporation method were examined. Measurement was performed at 40 ° C. using an aqueous solution of 90 wt% ethanol as the supply solution. After the membrane was attached to the apparatus, the permeate collection was started 1 hour and a half after the start of pervaporation separation. Thereafter, the permeation flux up to 2 hours was Q1, the separation factor was α1, the permeation flux up to 4 hours was Q2, and the separation factor was α2.

The permeation flux (Q) is the membrane area (m ² ), the permeation amount (kg) per hour (h): kg / m ² · h, and the separation factor (α) is the permeation liquid with respect to the supply liquid. (H ₂ O / EtOH). As a result, Q1 = 0.54 kg / m ² · h, α1 = 455, Q2 = 0.47 kg / m ² · h, and α2 = 630.

(Influence of secondary growth time)
The PHI seed crystal synthesis method, fixing method, and secondary growth method were the same as in Example 8, except that the secondary growth time was 8 hours at 150 ° C. After completion of hydrothermal synthesis, the autoclave was cooled with water, the mullite tube was taken out, and the mullite tube was washed with ion-exchanged water. Thereafter, it was dried in air for 24 hours. This film also confirmed by an XRD pattern that the outer surface was covered only with PHI crystals. From the result of SEM observation, the film thickness was about 8-10 μm. A gel-like product was also confirmed on the surface.

FIG. 4 shows an SEM image of the surface of the PHI film that has been subjected to secondary growth for 8 hours. As in Example 8, the evaluation of the separation performance by the pervaporation method of the PHI membrane with the secondary growth time of 8 hours at 150 ° C. was performed. As a result, Q1 = 0.42 kg / m ² · h, α1 = 20 Q2 = 0.46 kg / m ² · h and α2 = 18. The reason why Q and α were lower than in Example 8 is considered to be that a gel-like product was generated on the film surface.

  The PHI seed crystal synthesis method, fixing method, and secondary growth method were the same as in Example 8 except that the secondary growth time was 12 hours at 150 ° C. After completion of hydrothermal synthesis, the autoclave was cooled with water, the mullite tube was taken out, and the mullite tube was washed with ion-exchanged water. Thereafter, it was dried in air for 24 hours. This film also confirmed by an XRD pattern that the outer surface was covered only with PHI crystals. From the result of SEM observation, the film thickness was about 15-18 μm. The surface had almost no gel-like product and was in the form of aggregated spherical crystals.

FIG. 5 shows an SEM image of the surface of the PHI film that has been subjected to secondary growth for 12 hours. In the same manner as in Example 8, the separation performance was evaluated by the pervaporation method of the PHI membrane in which the secondary growth time was 12 hours at 150 ° C. As a result, Q1 = 0.28 kg / m ² · h, α1 = 750 Q2 = 0.30 kg / m ² · h, and α2 = 1060.

  The PHI seed crystal synthesis method, fixing method, and secondary growth method were the same as in Example 8 except that the secondary growth time was 24 hours at 150 ° C. After completion of hydrothermal synthesis, the autoclave was cooled with water, the mullite tube was taken out, and the mullite tube was washed with ion-exchanged water. Thereafter, it was dried in air for 24 hours. This film also confirmed by an XRD pattern that the outer surface was covered only with PHI crystals. From the result of SEM observation, the film thickness was about 35-40 μm. The surface had almost no gel-like product and had a form in which spherical crystals were densely assembled.

FIG. 6 shows an SEM image of the surface of the PHI film that has been subjected to secondary growth for 24 hours. As in Example 8, the separation performance was evaluated by the pervaporation method of the PHI membrane in which the secondary growth time was 24 hours at 150 ° C. As a result, Q1 = 0.24 kg / m ² · h, α1 = 4500 As described above, Q2 = 0.24 kg / m ² · h and α2 = 4500 or more.

(Effect of membrane cleaning method and water immersion)
A PHI film was synthesized by the method of Example 8. However, after completion of hydrothermal synthesis at 150 ° C. for 6 hours, the autoclave was cooled with water, and then the mullite tube was taken out, and when the mullite tube was washed with ion-exchanged water, rinsing and immersion were repeated three times. The XRD pattern confirmed that the outer surface of the film was covered only with PHI crystals. From the result of SEM observation, the film thickness was about 8-10 μm. The surface had almost no gel-like product and was in the form of aggregated spherical crystals.

Further, before the separation performance was evaluated by the pervaporation method, it was immersed in ion-exchanged water for about 1 hour and then attached to the apparatus. After that, as in Example 8, the separation performance of this PHI membrane was evaluated by the pervaporation method. As a result, Q1 = 0.29 kg / m ² · h, α1 = 4500 or more, Q2 = 0.35 kg / m ² H, α2 = 4500 or more. As compared with Example 8, it was found that although Q was decreased, α was remarkably improved.

  A PHI film was synthesized by the method of Example 9. However, after completion of hydrothermal synthesis at 150 ° C. for 8 hours, the autoclave was cooled with water, and then the mullite tube was taken out and rinsed and immersed three times when the mullite tube was washed with ion-exchanged water. The XRD pattern confirmed that the outer surface of the film was covered only with PHI crystals. From the result of SEM observation, the film thickness was about 10-12 μm. The surface had almost no gel-like product and was in the form of aggregated spherical crystals.

Further, before the separation performance was evaluated by the pervaporation method, it was immersed in ion-exchanged water for about 1 hour and then attached to the apparatus. Thereafter, as in Example 9, the separation performance of the PHI membrane was evaluated by the pervaporation method. As a result, Q1 = 0.33 kg / m ² · h, α1 = 4500 or more, Q2 = 0.39 kg / m ² H, α2 = 4500 or more. As compared with Example 9, it was found that although Q was decreased, α was remarkably improved.

  A PHI film was synthesized by the method of Example 10. However, after completion of hydrothermal synthesis at 150 ° C. for 12 hours, the autoclave was cooled with water, and then the mullite tube was taken out, and when the mullite tube was washed with ion-exchanged water, rinsing and immersion were repeated three times. The XRD pattern confirmed that the outer surface of the film was covered only with PHI crystals. From the result of SEM observation, the film thickness was about 15-18 μm. The surface had almost no gel-like product and was in the form of aggregated spherical crystals.

Further, before the separation performance was evaluated by the pervaporation method, it was immersed in ion-exchanged water for about 1 hour and then attached to the apparatus. Thereafter, as in Example 10, the separation performance of this PHI membrane was evaluated by the pervaporation method. As a result, Q1 = 0.38 kg / m ² · h, α1 = 4500 or more, Q2 = 0.32 kg / m ² H, α2 = 4500 or more. Compared to Example 10, it was found that both Q and α were significantly improved.

  A PHI film was synthesized by the method of Example 11. However, after completion of hydrothermal synthesis at 150 ° C. for 24 hours, the autoclave was cooled with water, and then the mullite tube was taken out and rinsed and immersed three times when the mullite tube was washed with ion-exchanged water. The XRD pattern confirmed that the outer surface of the film was covered only with PHI crystals. From the result of SEM observation, the film thickness was about 35-40 μm. The surface had almost no gel-like product and had a form in which spherical crystals were densely assembled.

Further, before the separation performance was evaluated by the pervaporation method, it was immersed in ion-exchanged water for about 1 hour and then attached to the apparatus. Thereafter, as in Example 11, the separation performance of this PHI membrane was evaluated by the pervaporation method. As a result, Q1 = 0.27 kg / m ² · h, α1 = 4500 or more, Q2 = 0.32 kg / m ² H, α2 = 4500 or more. As compared with Example 11, it was found that Q was remarkably improved.

  As described above, it has been clarified that the separation performance greatly changes only by changing the washing method after the PHI membrane synthesis and the membrane surface treatment method before the pervaporation separation. This is because, in the case of a PHI film which is a hydrophilic film, when the synthesis time is short (Examples 8 and 9, 10), in addition to the PHI crystal constituting the film, an amorphous gel portion or other crystal phase ( In the case of PHI, chabasite and mordenite tend to be mixed), which means that these effects need to be removed in order to obtain higher performance separation performance.

  In the above examples, these mixed crystals were not observed in the XRD pattern because the weight was 5% or less (only PHI as the main phase was observed in XRD). ). In fact, in Examples 8 and 9, from the SEM observation of the film surface, an amorphous gel was observed in addition to the PHI crystal.

  A PHI film was synthesized by the method of Example 11. However, after completion of hydrothermal synthesis at 150 ° C. for 24 hours, the autoclave is cooled with water, the mullite tube is taken out, and when the mullite tube is washed with ion-exchanged water, it is rinsed only once and immersed in ion-exchanged water. Did not. The XRD pattern confirmed that the outer surface of the film was covered only with PHI crystals. From the result of SEM observation, the film thickness was about 35-40 μm. The surface had almost no gel-like product and had a form in which spherical crystals were densely assembled.

FIG. 7 shows an SEM image of the PHI film surface without cleaning. When evaluating the separation performance by the pervaporation method, drying was performed at 60 ° C. for 24 hours. As a result, Q1 = 0.22 kg / m ² · h, α1 = 290, Q2 = 0.17 kg / m ² · h, and α2 = 350. Compared to Example 4, Q and α decreased.

(NaOH aqueous solution treatment)
A PHI film was synthesized by the method of Example 11. That is, the secondary growth condition was set at 150 ° C. for 24 hours. Thereafter, the membrane was immersed in an aqueous 0.1N NaOH solution for 3 hours, and finally immersed in ion-exchanged water for 24 hours. The XRD pattern confirmed that the outer surface of the film was covered only with PHI crystals. From the result of SEM observation, the film thickness was about 35-40 μm. The surface had almost no gel-like product and had a form in which spherical crystals almost the same as the film of Example 11 were densely assembled. Moreover, in the NaOH aqueous solution which processed the film | membrane, there existed the solid substance which seems to have peeled off from the film | membrane surface. As a result of powder XRD analysis, this solid was found to be PHI containing an amorphous halo peak. Thus, it was found that PHI on the film surface and mullite as a support were peeled and dissolved by the NaOH aqueous solution treatment.

FIG. 8 shows an SEM image of the surface of the PHI film after the treatment with the 0.1N NaOH aqueous solution. As in Example 8, the separation performance of the PHI membrane treated with aqueous NaOH was evaluated by the pervaporation method. As a result, Q1 = 0.28 kg / m ² · h, α1 = 24, Q2 = 0.30 kg / m ² · h, α2 = 40. Compared to Example 4, α decreased by two orders of magnitude.

(Film surface polishing with toothbrush)
A PHI film was synthesized by the method of Example 11. That is, the secondary growth condition was set at 150 ° C. for 24 hours. Thereafter, the surface of the PHI membrane was polished using a commercially available toothbrush in 200 mL of ion exchange water. The XRD pattern confirmed that the outer surface of the film was covered only with PHI crystals. From the result of SEM observation, the film thickness was about 25-30 μm, which was slightly thinner than the film thickness of Example 11. The surface had almost no gel-like product, and the spherical aggregates observed in the film of Example 11 were smooth. Moreover, in the ion-exchange water which processed the film | membrane, there existed the solid substance which seems to have peeled off from the film | membrane surface. As a result of powder XRD analysis, this solid was found to be PHI crystals. Thus, it was found that the PHI film on the film surface was partly peeled off by the film surface polishing treatment with a toothbrush.

FIG. 9 shows an SEM image of the surface of the PHI film after toothbrush polishing. As in Example 8, as a result of evaluating the separation performance of the PHI membrane subjected to membrane surface polishing treatment with this toothbrush by the pervaporation method, Q1 = 0.24 kg / m ² · h, α1 = 3860, Q2 = 0. It was 19 kg / m ² · h and α2 = 3360. Even when compared with Example 11, good results were obtained in which Q and α were not inferior. Thus, it was found that even if PHI crystals existing on the surface of the membrane were removed, the separation performance was hardly affected.

(Membrane surface polishing with sandpaper)
A PHI film was synthesized by the method of Example 11. That is, the secondary growth condition was set at 150 ° C. for 24 hours. Thereafter, for the purpose of further forcibly peeling the PHI crystal on the surface of the film, the surface of the PHI film was polished using a commercially available No. 1000 sandpaper. The PHI crystal on the outer surface was peeled off by rolling the sandpaper along the outer diameter of the membrane and reciprocating up and down 30 times. From the result of SEM observation, it was observed that the crystal of the spherical aggregate peculiar to PHI was scraped off on the film surface.

FIG. 10 shows an SEM image of the PHI film surface after sandpaper polishing. As in Example 8, the separation performance of the PHI membrane that had been subjected to membrane surface polishing treatment with sandpaper was evaluated by the pervaporation method. As a result, Q1 = 0.22 kg / m ² · h, α1 = 1450, Q2 = 0 .22 kg / m ² · h, α2 = 3000. Even when compared with Example 11, good results were obtained in which Q and α were not inferior. Thus, it was found that the separation performance was hardly affected even if PHI crystals existing on the membrane surface were removed as in Example 18.

(Film surface treatment by ultrasonic treatment)
A PHI film was synthesized by the method of Example 11. That is, the secondary growth condition was set at 150 ° C. for 24 hours. Thereafter, 200 mL of ion exchange water was taken into the beaker, the PHI membrane was immersed in the beaker, and subjected to ultrasonic treatment for 1 hour using a commercially available 500 W ultrasonic cleaner (As One, US-4 type). From the results of SEM observation, it was observed that the spherical surface crystals peculiar to PHI were scraped off and the surface of the film was smooth. Further, macroscopic cracks were observed on the film surface.

FIG. 11 shows an SEM image of the PHI film surface after ultrasonic treatment. As in Example 8, the separation performance of the PHI membrane subjected to this ultrasonic treatment was evaluated by the pervaporation method. As a result, Q1 = 0.28 kg / m ² · h, α1 = 4500 or more, Q2 = 0. It was 32 kg / m ² · h and α2 = 4500 or more. Even when compared with Example 11, good results were obtained in which Q and α were not inferior. Thus, as in Example 19, it was found that even if PHI crystals existing on the surface of the membrane were removed, the separation performance was hardly affected. In addition, separation performance appeared on the surface of the membrane despite the fact that macroscopic cracks were observed.

  From the results of Examples 17 to 20, when the PHI seed crystal is secondarily grown on the surface of the mullite tube and used as a separation membrane, the surface treatment of the membrane will cause higher separation ability to appear. I understood. Examples 8 to 20 are summarized in Table 1.

(Membrane change over time)
In Examples 12 to 15, it was shown that α was improved by immediately starting separation performance evaluation after water immersion with respect to the influence of water immersion during the separation performance evaluation by the pervaporation method. Using the PHI membrane synthesized by the method, the change with time up to 60 hours was measured. As a result, Q was stable at around 0.5 kg / m ² · h within this time, but α increased from the initial 450 (α1) to 1500 after 40 hours. Thereafter, until 60 hours, α was 1500, which was found to be stable. FIG. 12 shows changes with time in pervaporation separation of the PHI membrane.

  As described above in detail, the present invention relates to applications such as a Philipsite type zeolite membrane, a production method thereof, and a separation membrane thereof. According to the present invention, a PHI membrane that has not been reported so far is porously supported. It became clear that it could be synthesized into the body. According to the present invention, a hydrophilic zeolite membrane excellent in acid resistance and chemical resistance can be synthesized. For example, a zeolite membrane that can be employed for industrial liquid and gas separation processes, In addition, it can be manufactured and provided in a short period of time. The PHI membrane of the present invention can also be applied as a membrane reactor having both separation and catalytic action in the petrochemical industry. The present invention is particularly useful for providing new technologies and new products related to PHI membranes that can be suitably used as separation membranes in systems that require acid resistance.

An electron micrograph of a PHI type zeolite membrane (a: PHI-coated mullite tube cross section, b: PHI membrane surface) is shown. The result of acid resistance comparison of PHI type and FAU type zeolite is shown. The SEM image of the PHI film | membrane surface grown by secondary growth for 6 hours is shown. The SEM image of the PHI film | membrane surface grown by secondary growth for 8 hours is shown. An SEM image of the surface of a PHI film that has been subjected to secondary growth for 12 hours is shown. An SEM image of the surface of a PHI film that has been subjected to secondary growth for 24 hours is shown. The SEM image of the PHI film | membrane surface without washing | cleaning is shown. The SEM image of the PHI film | membrane surface after 0.1N-NaOH aqueous solution process is shown. The SEM image of the PHI film | membrane surface after toothbrush grinding | polishing is shown. The SEM image of the PHI film | membrane surface after sandpaper grinding | polishing is shown. The SEM image of the PHI film | membrane surface after ultrasonication is shown. The time-dependent change in the pervaporation separation of a PHI membrane is shown.

Claims (12)

A zeolite membrane formed on a support substrate, the structure of which is a philipsite (PHI) membrane formed on a support and has characteristics of high hydrophilicity and high acid resistance film.   The zeolite membrane according to claim 1, wherein the substrate is a metal and / or metal oxide substrate.   The zeolite membrane according to claim 2, wherein the substrate is an alumina, mullite, zirconia, or SUS porous substrate.   The zeolite membrane according to claim 1, wherein the PHI membrane has non-permeability that does not allow air to pass therethrough.   A separation membrane comprising the highly hydrophilic and highly acid-resistant zeolite membrane according to any one of claims 1 to 4.   The separation membrane according to claim 5, which is a hydrophilic zeolite membrane for dehydration.   A membrane reactor capable of simultaneously performing separation and reaction, comprising the highly hydrophilic and highly acid-resistant zeolite membrane according to any one of claims 1 to 4.   Using a raw material solution having a PHI composition, a PHI zeolite membrane is formed on a support substrate by a method of converting to a zeolite by a hydrothermal synthesis method or a method of converting an aluminosilicate gel to a zeolite by a steam treatment. A method for producing a zeolite membrane.   By applying seed crystals prepared using a raw material solution having a PHI composition to a porous support substrate and then converting to zeolite by hydrothermal synthesis or by converting aluminosilicate gel to zeolite by steam treatment The method for producing a zeolite membrane according to claim 8, wherein a PHI zeolite membrane is formed on the porous support substrate.   The method for producing a zeolite membrane according to claim 9, wherein the seed crystal is secondarily grown to form a continuous membrane.   The method for producing a zeolite membrane according to claim 8 or 9, wherein the membrane is subjected to a surface treatment after the synthesis of the PHI membrane.   The surface treatment of the film is performed by alkaline aqueous solution treatment, polishing treatment, or ultrasonic treatment to remove PHI crystals, amorphous gel, and / or other crystal phases that are excessively present on the film surface. The manufacturing method of the zeolite membrane of description.