JP5903802B2 - Method for producing porous support-zeolite membrane composite - Google Patents

Description

  The present invention relates to a method for producing a porous support-zeolite membrane composite, and more specifically, a method for producing a zeolite membrane composite in which a specific treatment is performed after a zeolite membrane is formed on a porous support by hydrothermal synthesis. The present invention relates to a porous support-zeolite membrane composite obtained by the method. The porous support-zeolite membrane composite obtained by the present invention is capable of permeating and separating a highly permeable substance from a gas or liquid mixture containing an organic compound and concentrating the low permeable substance. .

Conventionally, separation or concentration of a gas or liquid mixture containing an organic compound is performed by distillation, azeotropic distillation, solvent extraction / distillation, adsorbent, etc., depending on the properties of the target substance. . However, these methods have drawbacks that they require a lot of energy or have a limited application range for separation and concentration.
In recent years, membrane separation and concentration methods using membranes such as polymer membranes and zeolite membranes have been proposed as separation methods instead of these methods. Polymer membranes such as flat membranes and hollow fiber membranes are excellent in processability, but have the disadvantage of low heat resistance. In addition, polymer membranes have low chemical resistance, and many of them swell when contacted with organic compounds such as organic solvents and organic acids, so that the range of application for separation and concentration is limited.

  Further, the zeolite membrane is usually used for separation and concentration as a zeolite membrane composite in which zeolite is formed into a membrane on a support. For example, the organic compound can be separated and concentrated by bringing a mixture of the organic compound and water into contact with the zeolite membrane composite and selectively permeating water. Separation and concentration using membranes of inorganic materials can reduce the amount of energy used compared to separation by distillation or adsorbent, and can be separated and concentrated in a wider temperature range than polymer membranes. It can also be applied to the separation of mixtures.

As a separation method using a zeolite membrane, for example, a method of selectively permeating water using an A-type zeolite membrane complex to concentrate alcohol (Patent Document 1), and a mordenite-type zeolite membrane complex using alcohol A method of selectively permeating water from a mixed system of water (Patent Document 2) or selectively permeating water from a mixed system of acetic acid and water using a ferrierite-type zeolite membrane composite. A method for separating and concentrating acetic acid (Patent Document 3) has been proposed.

JP-A-7-185275 JP 2003-144871 A JP 2000-237561 A

However, a zeolite membrane that has both sufficient throughput and separation performance for practical use and has resistance to organic compounds, particularly organic acids, has not yet been found. For example, the mordenite-type zeolite membrane composite of Patent Document 2 and the ferrierite-type zeolite membrane composite of Patent Document 3 have a small permeation flux and are insufficient for practical use. In addition, since the de-Al reaction proceeds under acidic conditions, the separation performance changes as the use time becomes longer, and use under conditions where an organic acid is present is not desirable. The A-type zeolite of Patent Document 1 has no acid resistance or water resistance, and its application range is limited.

  Therefore, the zeolite membrane has been treated with an alkaline solution as a means for improving the separation performance and the permeation flux (Journal of Membrane Science 218 (2003) 185-194). However, the zeolite dissolves when heated in the presence of alkali, as is generally known. Therefore, the alkali treatment can be performed only in a narrow range of conditions, for example, strictly keeping the treatment time. Therefore, a processing method having a wide range of conditions and requiring no strict control has been desired.

  The object of the present invention is to produce a porous support-zeolite membrane composite that achieves both a practically sufficient throughput and separation performance in separation and concentration using an inorganic material separation membrane, in which the problems of the prior art are solved. The present invention provides a method, a porous support-zeolite membrane composite obtained by the method, and a separation and concentration method using the zeolite membrane composite.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention can achieve both practically sufficient throughput and separation performance if a certain type of zeolite is formed into a film on an inorganic porous support. It has been found that a zeolite membrane composite can be obtained and proposed previously (Japanese Patent Application No. 2010-043366). As a result of further investigations, the present inventors made a zeolite membrane on a porous support to form a porous support-zeolite membrane composite, and then the zeolite membrane composite was subjected to certain temperature conditions. Thus, it was found that the separation performance of the zeolite membrane was drastically improved by being immersed in water. And preferably, it discovered that the isolation | separation performance of a zeolite membrane improved further by immersing in the water containing Si in water. The present invention has been accomplished based on these findings.

That is, the gist of the present invention resides in the following (1) to (1 1 ).
(1) A zeolite membrane containing a zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 5 or more is formed on a porous support by hydrothermal synthesis to form a zeolite membrane composite, and the zeolite membrane composite is after heat treatment at 50 ° C. or more, only the following water 300 ° C. temperature of 40 ° C. or higher, or a porous support, characterized in that immersing least 1 hour in water containing Si more than 20 wt% - zeolite membrane composite Manufacturing method.
(2) The method according to (1) above, wherein the amount of Si contained in the water is 0.01% by mass or more.
(3) further comprises acid water containing the Si, the method described in the above (2).
(4) The method according to (3) above, wherein the acid is one of an inorganic acid, a carboxylic acid, and a sulfonic acid.
(5) The method (6) according to the above (3) or (4), wherein the acid is any one of sulfuric acid, nitric acid, phosphoric acid, acetic acid, formic acid, and lactic acid. The method according to any one of 1) to (5).
(7) The method according to any one of (1) to (6), wherein the immersion in water is performed in a heatable container that can be sealed.
(8) The method according to any one of (1) to (7) above, wherein the OH- ¹ ion concentration in water is 0.05 mol / L or less.
(9) The method according to any one of (2) to (7) above, wherein the H ⁺ ion concentration in water is 0.00001 mol / L or more.
(10) The method according to any one of (1) to (9), wherein a heat treatment is further performed after immersion in water.
(1 1 ) A gas or liquid mixture containing an organic substance is brought into contact with the porous support-zeolite membrane composite produced by the method according to any one of 1 to 10 above, and the mixture is made permeable. A separation method characterized in that a high substance permeates and separates.

  According to the present invention, when a specific compound is separated and concentrated from a gas or liquid mixture containing an organic compound, the porous material has a zeolite membrane that has a sufficiently large treatment amount for practical use and has sufficient separation performance. A support-zeolite membrane composite is provided. By using this zeolite membrane composite as a separation means, it becomes possible to separate a highly permeable substance and concentrate the mixture from a gas or liquid mixture containing an organic compound, which achieves both sufficient throughput and separation performance. .

It is the schematic of the measuring apparatus used for the pervaporation method. It is the schematic of the measuring apparatus used for the vapor permeation method.

Hereinafter, embodiments of the present invention will be described in more detail. However, the description of the constituent elements described below is an example of embodiments of the present invention, and the present invention is not limited to these contents. Various modifications can be made within the scope of the gist.
In the method for producing a porous support-zeolite membrane composite of the present invention, a zeolite membrane containing a zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 5 or more is formed on a porous support by hydrothermal synthesis. A zeolite membrane composite is characterized in that the zeolite membrane composite is heat treated at a temperature of 50 ° C. or higher and then immersed in water at a temperature of 40 ° C. or higher and 300 ° C. or lower for 1 hour or longer.

The porous support-zeolite membrane composite of the present invention is characterized by being produced by the above method.
First, the constituent requirements of these inventions will be described in more detail. In the present specification, “porous support-zeolite membrane composite” is abbreviated as “zeolite membrane composite” or “membrane composite”, and “porous support” is abbreviated as “support”. is there.

(Porous support)
The porous support used in the present invention has a chemical stability such that zeolite can be crystallized in the form of a film on the surface thereof, and is a support made of an inorganic porous material (inorganic porous support). Anything may be used. For example, sintered ceramics (ceramics support) such as silica, α-alumina, γ-alumina, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide, sintered metals such as iron, bronze, and stainless steel, glass And carbon moldings.

Among these porous supports, there are inorganic porous supports (ceramic supports) including sintered ceramics, which are solid materials whose basic components or most of them are composed of inorganic nonmetallic substances. preferable. If this support is used, a part of the support is zeoliticized during the synthesis of the zeolite membrane, thereby improving the adhesion at the interface.
Specific examples include a ceramic sintered body (ceramic support) containing silica, α-alumina, γ-alumina, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide, and the like. Among them, an inorganic porous support containing at least one of alumina, silica, and mullite is preferable. When these supports are used, partial zeolitization is easy, so that the bond between the support and the zeolite becomes strong, and a dense membrane with high separation performance is easily formed.

The shape of the porous support is not particularly limited as long as it can effectively separate a gas mixture or a liquid mixture, and specifically, for example, a flat plate shape, a tubular shape, a cylindrical shape, a cylindrical shape, a prismatic shape, or the like. Honeycomb-like ones having a large number of pores, monoliths and the like can be mentioned.
In the present invention, zeolite is formed into a film on such a porous support, that is, on the surface of the support. The surface of the support may be any surface or a plurality of surfaces depending on the shape of the support. For example, in the case of a cylindrical tube support, it may be the outer surface or the inner surface, and in some cases both the outer and inner surfaces.

  The average pore diameter of the surface of the porous support is not particularly limited, but those having a controlled pore diameter are preferred, usually 0.02 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more. Usually, it is 20 μm or less, preferably 10 μm or less, more preferably 5 μm or less. If the average pore diameter is too small, the amount of permeation tends to be small, and if it is too large, the strength of the support itself is insufficient, and the proportion of pores on the surface of the support increases, making it difficult to form a dense zeolite membrane. Tend.

  The average thickness (wall thickness) of the support is usually 0.1 mm or more, preferably 0.3 mm or more, more preferably 0.5 mm or more, and usually 7 mm or less, preferably 5 mm or less, more preferably 3 mm or less. is there. The support is used to give mechanical strength to the zeolite membrane, but if the average thickness of the support is too thin, the zeolite membrane composite will not have sufficient strength and There is a tendency to weaken. If the average thickness of the support is too thick, the diffusion of the permeated material tends to be poor and the permeation flux tends to be low.

The porosity of the support is usually 20% or more, preferably 25% or more, more preferably 30% or more, and usually 70% or less, preferably 60% or less, more preferably 50% or less. The porosity of the support affects the permeation flow rate when separating gases and liquids, and tends to inhibit diffusion of the permeate below the lower limit, and tends to lower the strength of the support above the upper limit. The surface of the quality support is preferably smooth, and the surface may be polished with a file or the like as necessary. The surface of the porous support means the surface portion of the inorganic porous support that crystallizes the zeolite, and any surface of each shape may be used as long as the surface is a plurality of surfaces. Also good. For example, in the case of a cylindrical tube support, it may be the outer surface or the inner surface, and in some cases both the outer and inner surfaces.

(Zeolite membrane composite)
In the present invention, a zeolite membrane is formed on the porous support to obtain a zeolite membrane composite.
As a component constituting the zeolite membrane, an inorganic binder such as silica or alumina, an organic compound such as a polymer, a silylating agent for modifying the zeolite surface, or the like may be included as necessary in addition to zeolite. In addition, the zeolite membrane in the present invention may partially contain an amorphous component or the like, but a zeolite membrane substantially consisting only of zeolite is preferable.

The thickness of the zeolite membrane is not particularly limited, but is usually 0.1 μm or more, preferably 0.6 μm or more, more preferably 1.0 μm or more, and usually 100 μm or less, preferably 60 μm or less, more preferably 20 μm or less. It is. If the film thickness is too large, the amount of permeation tends to decrease. If it is too small, the selectivity tends to decrease or the film strength tends to decrease.
The particle diameter of the zeolite is not particularly limited, but if it is too small, the grain boundary tends to increase, and the permeation selectivity tends to decrease. Therefore, it is usually 30 nm or more, preferably 50 nm or more, more preferably 100 nm or more, and the upper limit is the film thickness or less. Furthermore, it is particularly preferred that the zeolite particle size is the same as the membrane thickness. When the zeolite particle size is the same as the membrane thickness, the zeolite grain boundary is smallest.

The zeolite is preferably an aluminosilicate, and its SiO ₂ / Al ₂ O
_{The 3} molar ratio is preferably 5 or more, more preferably 8 or more, further preferably 10 or more, particularly preferably 12 or more, preferably 2000 or less, more preferably 1000 or less, still more preferably 500 or less, particularly preferably. 100 or less. When the SiO ₂ / Al ₂ O ₃ molar ratio is less than the lower limit, the durability tends to decrease. When the SiO ₂ / Al ₂ O ₃ molar ratio exceeds the upper limit, the permeation flux tends to decrease because the hydrophobicity is too strong.

Incidentally, _SiO 2 / _Al 2 _{O 3} molar ratio in the present invention, a scanning electron microscope - is a value obtained by energy dispersive X-ray spectroscopy (SEM-EDX). In order to obtain information on only a film of several microns, the X-ray acceleration voltage is usually measured at 10 kV.
The main zeolite constituting the zeolite membrane preferably contains a zeolite having an oxygen 6-10 membered ring structure, more preferably a zeolite having an oxygen 6-8 membered ring structure.

Here, the value of n of the zeolite having an oxygen n-membered ring has the largest number of oxygen in the pores composed of oxygen forming the zeolite skeleton and T element (element other than oxygen constituting the skeleton). Show things. For example, when there are 12-membered and 8-membered pores of oxygen, such as MOR type zeolite, it is regarded as a 12-membered ring zeolite.
Examples of the zeolite having an oxygen 6 to 10-membered ring structure include AEI, AEL, AFG, ANA, BRE, CAS, CDO, CHA, DAC, DDR, DOH, EAB, EPI, ESV, EUO, FAR, FRA, and FER. , GIS, GIU, GOO, HEU, IMF, ITE, ITH, KFI, LEV, LIO, LOS, LTN, MAR, MEP, MER, MEL, MFI, MFS, MON, MSO, MTF, MTN, MTT, MWW, NAT , NES, NON, PAU, PHI, RHO, RRO, RTE, RTH, RUT, SGT, SOD, STF, STI, STT, TER, TOL, TON, TSC, TUN, UFI, VNI, VSV, WEI, YUG, etc. Can be mentioned.

Examples of the zeolite having an oxygen 6-8 membered ring structure include AEI, AFG, ANA, CHA, EAB, ERI, ESV, FAR, FRA, GIS, ITE, KFI, LEV, LIO, LOS, LTN, MAR, and PAU. , RHO, RTH, SOD, STI, TOL, UFI and the like.
The oxygen n-membered ring structure determines the size of the pores of the zeolite. In the case of zeolite smaller than the 6-membered ring, the permeation flux becomes smaller because the pore diameter is smaller than the kinetic diameter radius of the H ₂ O molecule, and the permeation flux becomes smaller. May not be right. Moreover, when it is larger than the oxygen 10-membered ring structure, the pore diameter becomes large, and the organic compound having a small size may deteriorate the separation performance, and the use may be limited.

The framework density (T / 1000 ³ ) of the zeolite is not particularly limited, but is usually 17 or less, preferably 16 or less, more preferably 15.5 or less, particularly preferably 15 or less, usually 10 or more, preferably 11 or more. More preferably, it is 12 or more.
The framework density means the number of elements (T element) other than oxygen constituting the framework per 1000 ³ of the zeolite, and this value is determined by the structure of the zeolite. The relationship between framework density and zeolite structure is ATLAS OF ZEOLITE FRAMEWORK TYPES.
Shown in Fifth Revised Edition 2001 ELSEVIER.

  In the present invention, preferred zeolite structures are AEI, AFG, CHA, EAB, ERI, ESV, FAR, FRA, GIS, ITE, KFI, LEV, LIO, LOS, LTN, MAR, PAU, RHO, RTH, SOD, STI, TOL, UFI, more preferred structures are AEI, CHA, ERI, KFI, LEV, PAU, RHO, RTH, UFI, more preferred structures are CHA, LEV, and the most preferred structure is CHA. is there.

  Here, the CHA-type zeolite is a code that defines the structure of the zeolite defined by the International Zeolite Association (IZA) and indicates a CHA structure. This is a zeolite having a crystal structure equivalent to that of naturally occurring chabazite. The CHA-type zeolite has a structure characterized by having three-dimensional pores composed of 8-membered oxygen rings having a diameter of 3.8 × 3.8 mm, and the structure is characterized by X-ray diffraction data.

The framework density (T / 1000 ³ ) of the CHA-type zeolite is 14.5. The SiO ₂ / Al ₂ O ₃ molar ratio is the same as described above.
In the present invention, when the zeolite membrane contains CHA-type zeolite, the intensity of the peak in the vicinity of 2θ = 17.9 ° is 2θ = 20.
The size is preferably 0.5 times or more the peak intensity around 8 °.

Here, the peak intensity refers to a value obtained by subtracting the background value from the measured value. The peak intensity ratio represented by (the intensity of the peak around 2θ = 17.9 °) / (the intensity of the peak around 2θ = 20.8 °) (hereinafter this may be referred to as “peak intensity ratio A”). In other words, it is usually 0.5 or more, preferably 1 or more, more preferably 1.2 or more, and particularly preferably 1.5 or more. Although an upper limit is not specifically limited, Usually, it is 1000 or less.

Further, in the zeolite membrane composite, when the zeolite membrane contains CHA-type zeolite, the peak intensity around 2θ = 9.6 ° is 4 of the peak intensity around 2θ = 20.8 ° in the X-ray diffraction pattern. The size is preferably twice or more.
Peak intensity ratio represented by (Intensity of peak near 2θ = 9.6 °) / (Intensity of peak near 2θ = 20.8 °) (hereinafter this may be referred to as “peak intensity ratio B”) In other words, it is usually 4 or more, preferably 6 or more, more preferably 8 or more, and particularly preferably 10 or more. Although an upper limit is not specifically limited, Usually, it is 1000 or less.

  Here, the X-ray diffraction pattern is obtained by irradiating the surface on which zeolite is mainly attached with X-rays using CuKα as a radiation source to obtain a scanning axis of θ / 2θ. The shape of the sample to be measured may be any shape that can irradiate the surface of the membrane composite to which the zeolite is mainly attached, with X-ray irradiation. The body itself or the one cut into an appropriate size restricted by the apparatus is preferable.

Here, the X-ray diffraction pattern may be measured by fixing the irradiation width using an automatic variable slit when the surface of the zeolite membrane composite is a curved surface. An X-ray diffraction pattern using an automatic variable slit refers to a pattern subjected to variable → fixed slit correction.
Here, the peak in the vicinity of 2θ = 17.9 ° refers to the maximum of the peaks present in the range of 17.9 ° ± 0.6 ° among the peaks not derived from the base material.

The peak in the vicinity of 2θ = 20.8 ° refers to the maximum peak in the range of 20.8 ° ± 0.6 ° among the peaks not derived from the base material.
The peak in the vicinity of 2θ = 9.6 ° refers to the maximum of the peaks present in the range of 9.6 ° ± 0.6 ° among the peaks not derived from the base material.
According to COLLECTION OF SIMULATED XRD POWDER PATTERNS FOR ZEOLITE Third Revised Edition 1996 ELSEVIER, the peak near 2θ = 9.6 ° in the X-ray diffraction pattern is a rhombohedral setting.

(No. 166), it is a peak derived from the plane having an index of (1, 0, 0) in the CHA structure.
In addition, the peak near 2θ = 17.9 ° in the X-ray diffraction pattern shows the space group in rhombohedral setting according to COLLECTION OF SIMULATED XRD POWDER PATTERNS FOR ZEOLITE Third Revised Edition 1996 ELSEVIER.

(No. 166) is a peak derived from the (1,1,1) index in the CHA structure.
The peak near 2θ = 20.8 ° in the X-ray diffraction pattern is a collection of SIMULATED XRD POWDER PATTERNS FOR ZEOLITE Third Revised Edition 1996 ELSEVIER.

(No. 166) is a peak derived from the (2, 0, -1) index in the CHA structure.
The typical ratio (peak intensity ratio B) of the peak intensity derived from the (1, 0, 0) plane and the peak intensity derived from the (2, 0, -1) plane (peak intensity ratio B) is COLLECTION OF SIMULATED XRD POWDER PATTERNS FOR ZEOLITE According to Third Revised Edition 1996 ELSEVIER, it is 2.5.

  Therefore, when this ratio is 4 or more, for example, the zeolite crystal is oriented so that the (1, 0, 0) plane is almost parallel to the surface of the membrane composite when the CHA structure is a rhombohedral setting. Is considered to mean that the crystals are oriented and growing. Orientation and growth of zeolite crystals in the zeolite membrane composite is advantageous in that a dense membrane with high separation performance can be formed.

The typical ratio (peak intensity ratio A) of the peak intensity derived from the (1, 1, 1) plane and the peak intensity derived from the (2, 0, -1) plane (peak intensity ratio A) is COLLECTION OF SIMULATED XRD POWDER PATTERNS FOR ZEOLITE According to Third Revised Edition 1996 ELSEVIER, it is 0.3.
Therefore, this ratio of 0.5 or more means, for example, that the (1, 1, 1) plane when the CHA structure is a rhombohedral setting is oriented so that the orientation is almost parallel to the surface of the membrane composite. It is thought to mean that the crystals are oriented and growing. Orientation and growth of zeolite crystals in the zeolite membrane composite is advantageous in that a dense membrane with high separation performance can be formed.

As described above, the fact that any one of the peak intensity ratios A and B is a value in the above-mentioned specific range means that the zeolite crystals are oriented and grow, and a dense membrane with high separation performance is formed. Is shown.
As described below, a dense zeolite membrane in which CHA-type zeolite crystals are grown in an orientated state is formed in an aqueous reaction mixture using, for example, a specific organic template when the zeolite membrane is formed by hydrothermal synthesis. This can be achieved by coexisting K ⁺ ions.

(Method for producing zeolite membrane composite)
In the present invention, a zeolite membrane is formed on a porous support by hydrothermal synthesis to prepare a zeolite membrane composite.
Specifically, for example, a reaction mixture for hydrothermal synthesis (hereinafter sometimes referred to as an “aqueous reaction mixture”) having a uniform composition is adjusted, and the porous support is gently fixed inside. What is necessary is just to heat in a heat-resistant pressure-resistant container, such as an autoclave, and to seal for a fixed time.

The aqueous reaction mixture preferably contains an Si element source, an Al element source, an organic template and water as necessary, and an alkali source as necessary.
Examples of the Si element source used in the aqueous reaction mixture include amorphous silica, colloidal silica, silica gel, sodium silicate, amorphous aluminum silicate gel, tetraethoxysilane (TEOS), trimethylethoxysilane, and the like.

As the Al element source, for example, sodium aluminate, aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum oxide, amorphous aluminosilicate gel, or the like can be used. In addition to the Al element source, other element sources, for example, element sources such as Ga, Fe, B, Ti, Zr, Sn, and Zn may be included.
In crystallization of zeolite, an organic template (structure directing agent) can be used as necessary, but those synthesized using an organic template are preferred. By synthesizing using the organic template, the ratio of silicon atoms to aluminum atoms in the crystallized zeolite is increased, and the acid resistance is improved.

The organic template may be any type as long as it can form a desired zeolite membrane. Further, one type of template or a combination of two or more types may be used.
When the zeolite is of the CHA type, amines and quaternary ammonium salts are usually used as the organic template. For example, organic templates described in U.S. Pat. No. 4,544,538 and U.S. Patent Publication No. 2008/0075656 are preferred.

Specific examples include cations derived from alicyclic amines such as cations derived from 1-adamantanamine, cations derived from 3-quinacridinal, and cations derived from 3-exo-aminonorbornene. It is done. Among these, a cation derived from 1-adamantanamine is more preferable.
When a cation derived from 1-adamantanamine is used as an organic template, CHA-type zeolite capable of forming a dense film is crystallized. In addition, a CHA-type zeolite having hydrophilicity sufficient for the membrane to selectively permeate water can be generated, and a CHA-type zeolite excellent in acid resistance can be obtained.

  Of the cations derived from 1-adamantanamine, the N, N, N-trialkyl-1-adamantanammonium cation is more preferred. The three alkyl groups of the N, N, N-trialkyl-1-adamantanammonium cation are usually independent alkyl groups, preferably a lower alkyl group, more preferably a methyl group. The most preferred compound among them is the N, N, N-trimethyl-1-adamantanammonium cation.

Such cations are accompanied by anions that do not harm the formation of CHA-type zeolite.
Representative examples of such anions include halogen ions such as Cl ⁻ , Br ⁻ and I ⁻ , hydroxide ions, acetates, sulfates, and carboxylates. Of these, hydroxide ions are particularly preferably used.
As another organic template, N, N, N-trialkylbenzylammonium cation can also be used. Also in this case, the alkyl group is an independent alkyl group, preferably a lower alkyl group, more preferably a methyl group. Among them, the most preferred compound is N, N, N-trimethylbenzylammonium cation. The anion accompanied by this cation is the same as described above.

As an alkali source used in the aqueous reaction mixture, a hydroxide ion of a counter anion of an organic template, an alkali metal hydroxide such as NaOH or KOH, or an alkaline earth metal hydroxide such as Ca (OH) ₂ is used. Can do.
The type of alkali is not particularly limited, and Na, K, Li, Rb, Cs, Ca, Mg, Sr, Ba and the like are usually used. Among these, Na and K are preferable, and K is more preferable. Further, two or more alkalis may be used in combination, and specifically, Na and K are preferably used in combination.

The ratio of Si element source to Al element source in the aqueous reaction mixture is usually expressed as the molar ratio of the oxides of the respective elements, that is, the SiO ₂ / Al ₂ O ₃ molar ratio.
The SiO ₂ / Al ₂ O ₃ molar ratio is not particularly limited, but is usually 5 or more, preferably 8 or more, more preferably 10 or more, and further preferably 15 or more. Further, it is usually 10,000 or less, preferably 1000 or less, more preferably 300 or less, and still more preferably 100 or less.

When the SiO ₂ / Al ₂ O ₃ molar ratio is within this range, the zeolite membrane is densely formed, and the produced zeolite exhibits strong hydrophilicity, and a hydrophilic compound, particularly water, is selected from the mixture containing the organic compound. Can be selectively transmitted. In addition, a zeolite membrane that is strong in acid resistance and difficult to remove from Al can be obtained.
In particular, when the SiO ₂ / Al ₂ O ₃ molar ratio is within this range, CHA-type zeolite that can form a dense film can be crystallized. In addition, a CHA-type zeolite having hydrophilicity sufficient for the membrane to selectively permeate water can be generated, and a CHA-type zeolite excellent in acid resistance can be obtained.

The ratio of the silica source and an organic template in the aqueous reaction mixture, the molar ratio of the organic template for SiO ₂ (organic template / SiO ₂ molar ratio), usually 0.005 or higher, preferably at least 0.01, more preferably 0 0.02 or more, usually 1 or less, preferably 0.4 or less, more preferably 0.2 or less.
When the organic template / SiO ₂ molar ratio is in the above range, in addition to being able to produce a dense zeolite membrane, the produced zeolite has strong acid resistance and Al is not easily desorbed. Moreover, a particularly dense and acid-resistant CHA-type zeolite can be formed under these conditions.

The ratio of the Si element source to the alkali source is M _{(2 / n) 2} O / SiO ₂ (where M represents an alkali metal or alkaline earth metal, and n represents the valence 1 or 2). In general, it is 0.02 or more, preferably 0.04 or more, more preferably 0.05 or more, and usually 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less.
In the case of forming a CHA-type zeolite membrane, it is preferable that K is contained in the alkali metal because a denser and highly crystalline membrane is formed. In that case, the molar ratio of K to all alkali metals and / or alkaline earth metals containing K is usually 0.01 or more and 1 or less, preferably 0.1 or more and 1 or less, more preferably 0.3 or more and 1 It is as follows.

  As described above, the addition of K to the aqueous reaction mixture is performed by changing the space group in the rhombohedral setting.

(No. 166), the peak intensity in the vicinity of 2θ = 9.6 °, which is a peak derived from the (1, 0, 0) index surface in the CHA structure, and the (2, 0, −1) surface The peak intensity ratio in the vicinity of 2θ = 20.8 ° (peak intensity ratio B), which is a peak derived from the above, or the peak derived from the plane of (1,1,1), in the vicinity of 2θ = 17.9 ° There is a tendency to increase the ratio between the peak intensity and the peak intensity in the vicinity of 2θ = 20.8 ° (peak intensity ratio A), which is a peak derived from the (2, 0, −1) plane.

The ratio of Si element source to water is the molar ratio of water to SiO ₂ (H ₂ O / SiO ₂ molar ratio), which is usually 10 or more, preferably 30 or more, more preferably 40 or more, and particularly preferably 50 or more. Usually, it is 1000 or less, preferably 500 or less, more preferably 200 or less, and particularly preferably 150 or less.
When the molar ratio of materials in the aqueous reaction mixture is in these ranges, a dense zeolite membrane can be formed. The amount of water is particularly important in the formation of a dense zeolite membrane, and finer crystals are more likely to form and form a dense membrane when the amount of water is greater than that of the general powder synthesis method. is there.

In general, the amount of water in the synthesis of powdered CHA-type zeolite is about 15 to 50 in terms of H ₂ O / SiO ₂ molar ratio. Zeolite membrane composite with high separation performance in which CHA-type zeolite is crystallized into a dense membrane on the support by using a high H ₂ O / SiO ₂ molar ratio (50 to 1000), that is, water-rich conditions. You can get a body.
Further, in the hydrothermal synthesis, it is not always necessary to have a seed crystal in the reaction system, but by adding the seed crystal, crystallization of the zeolite can be promoted on the support. The method of adding the seed crystal is not particularly limited, and a method of adding the seed crystal to the aqueous reaction mixture or the method of attaching the seed crystal on the support as in the synthesis of the powdered zeolite is used. Can do. When producing a zeolite membrane composite, it is preferable to attach a seed crystal on the support. By attaching a seed crystal in advance to the support, a dense zeolite membrane with good separation performance can be easily formed.

The seed crystal to be used is not limited as long as it is a zeolite that promotes crystallization, but it is preferably the same crystal type as the zeolite membrane to be formed for efficient crystallization. When forming a CHA type zeolite membrane, it is preferable to use seed crystals of CHA type zeolite.
The particle diameter of the seed crystal is usually 0.5 nm or more, preferably 1 nm or more, more preferably 2 nm or more, and is usually 20 μm or less, preferably 15 μm or less, more preferably 10 μm or less.

As a method for adding a seed crystal, a method of adding it to an aqueous reaction mixture as in the synthesis of a powdered zeolite, a method of attaching a seed crystal on a support, and the like can be used. It is preferable to attach a seed crystal. By attaching a seed crystal in advance to the support, a dense zeolite membrane with good separation performance can be easily formed.
The seed crystal to be used is not limited as long as it is a zeolite that promotes crystallization, but it is preferably the same crystal type as the zeolite membrane to be formed for efficient crystallization. When forming a CHA type zeolite membrane, it is preferable to use seed crystals of CHA type zeolite.

  The method for attaching the seed crystal on the support is not particularly limited. For example, a dip method in which the seed crystal is dispersed in a solvent such as water and the support is immersed in the dispersion to attach the seed crystal, or a seed crystal is attached. For example, a method in which a slurry mixed with a solvent such as water is coated on a support can be used. The dip method is desirable for controlling the amount of seed crystals attached and producing a membrane composite with good reproducibility.

The solvent for dispersing the seed crystal is not particularly limited, but water is particularly preferable.
The amount of the seed crystal to be dispersed is not particularly limited, and is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, based on the total mass of the dispersion. Usually, it is 20 mass% or less, Preferably it is 10 mass% or less, More preferably, it is 5 mass% or less, More preferably, it is 4 mass% or less, Most preferably, it is 3 mass% or less.

  If the amount of seed crystals to be dispersed is too small, the amount of seed crystals adhering to the support is small, so that a portion where no zeolite is generated on the support during hydrothermal synthesis is created, resulting in a defective film. there is a possibility. The amount of seed crystals adhering to the support by the dip method becomes almost constant when the amount of seed crystals in the dispersion is higher than a certain level, so if the amount of seed crystals in the dispersion is too large, the seed crystals are wasted. It is more disadvantageous in terms of cost.

It is desirable to deposit the seed crystal on the support by dipping or slurry coating, and after drying, form a zeolite membrane.
The amount of the seed crystal to be preliminarily deposited on the support is not particularly limited, and is usually 0.01 g or more, preferably 0.05 g or more, more preferably 0.1 g or more, by mass per 1 m ^{2 of} the base material. Usually, it is 100 g or less, preferably 50 g or less, more preferably 10 g or less, still more preferably 8 g or less.

  When the amount of the seed crystal is less than the lower limit, it becomes difficult to form a crystal, and there is a tendency that the film growth becomes insufficient or the film growth becomes uneven. In addition, when the amount of the seed crystal exceeds the upper limit, surface irregularities are increased by the seed crystal, or spontaneous nuclei are likely to grow due to the seed crystal falling from the support, thereby inhibiting film growth on the support. Sometimes. In either case, it tends to be difficult to form a dense zeolite membrane.

When a zeolite membrane is formed on a support by hydrothermal synthesis, there are no particular limitations on the method for immobilizing the support, and it can take any form such as vertical or horizontal placement. In this case, the zeolite membrane may be formed by a stationary method, or the aqueous reaction mixture may be stirred to form a zeolite membrane.
The temperature at which the zeolite membrane is formed is not particularly limited, but is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 150 ° C. or higher, usually 200 ° C. or lower, preferably 190 ° C. or lower, more preferably 180 ° C. It is as follows. If the reaction temperature is too low, the zeolite may be difficult to crystallize. If the reaction temperature is too high, a zeolite of a type different from the zeolite in the present invention may be easily generated.

  The heating time is not particularly limited, but is usually 1 hour or more, preferably 5 hours or more, more preferably 10 hours or more, and usually 10 days or less, preferably 5 days or less, more preferably 3 days or less, and even more preferably 2 Less than a day. If the reaction time is too short, the zeolite may be difficult to crystallize. If the reaction time is too long, a zeolite of a type different from the zeolite in the present invention may be easily generated.

The pressure at the time of forming the zeolite membrane is not particularly limited, and the self-generated pressure generated when the aqueous reaction mixture placed in the closed vessel is heated to this temperature range is sufficient. If necessary, an inert gas such as nitrogen may be added.
The zeolite membrane composite obtained by hydrothermal synthesis is washed with water, then heated and dried. Here, the heat treatment means that the template is fired when heat is applied to dry the zeolite membrane composite or the template is used.

  The temperature of the heat treatment is usually 50 ° C. or higher, preferably 80 ° C. or higher, more preferably 100 ° C. or higher, usually 200 ° C. or lower, preferably 150 ° C. or lower when drying is intended. For the purpose of firing the template, it is usually 350 ° C. or higher, preferably 400 ° C. or higher, more preferably 430 ° C. or higher, still more preferably 480 ° C. or higher, usually 900 ° C. or lower, preferably 850 ° C. or lower, Preferably it is 800 degrees C or less, Most preferably, it is 750 degrees C or less.

The heating time is not particularly limited as long as the zeolite membrane is sufficiently dried or the template is calcined, and is preferably 0.5 hours or more, more preferably 1 hour or more. The upper limit is not particularly limited, and is usually within 200 hours, preferably within 150 hours, and more preferably within 100 hours.
When hydrothermal synthesis is performed in the presence of an organic template, the obtained zeolite membrane composite can be washed with water, and then the organic template can be removed by, for example, heat treatment or extraction, preferably by heat treatment, that is, baking. Is appropriate.

  The firing temperature is usually 350 ° C. or higher, preferably 400 ° C. or higher, more preferably 430 ° C. or higher, more preferably 480 ° C. or higher, usually 900 ° C. or lower, preferably 850 ° C. or lower, more preferably 800 ° C. or lower, particularly Preferably it is 750 degrees C or less. If the calcination temperature is too low, the proportion of the remaining organic template tends to increase, and the zeolite has fewer pores, which may reduce the permeation flux during separation and concentration. If the calcination temperature is too high, the difference in the coefficient of thermal expansion between the support and the zeolite becomes large, so that the zeolite membrane may be easily cracked, and the denseness of the zeolite membrane may be lost and the separation performance may be lowered.

  The firing time varies depending on the temperature rising rate or the temperature falling rate, but is not particularly limited as long as the organic template is sufficiently removed, and is preferably 1 hour or longer, more preferably 5 hours or longer. The upper limit is not particularly limited, and is, for example, usually within 200 hours, preferably within 150 hours, more preferably within 100 hours, and most preferably within 24 hours. Firing may be performed in an air atmosphere, but may be performed in an atmosphere to which oxygen is added.

It is desirable that the rate of temperature increase during firing be as slow as possible in order to reduce the difference in the thermal expansion coefficient between the support and the zeolite from causing cracks in the zeolite membrane. The temperature rising rate is usually 5 ° C./min or less, preferably 2 ° C./min or less, more preferably 1 ° C./min or less, and particularly preferably 0.5 ° C./min or less. Usually, it is 0.1 ° C./min or more in consideration of workability.
Moreover, it is necessary to control the temperature drop rate after firing in order to avoid cracks in the zeolite membrane. Similar to the rate of temperature increase, the slower the better. The temperature lowering rate is usually 5 ° C./min or less, preferably 2 ° C./min or less, more preferably 1 ° C./min or less, and particularly preferably 0.5 ° C./min or less. Usually, it is 0.1 ° C./min or more in consideration of workability.

The zeolite membrane may be ion exchanged as necessary. In the case of synthesizing using a template, ion exchange is usually performed after removing the template. Examples of ions to be ion-exchanged include protons, alkali metal ions such as Na ⁺ , K ⁺ and Li ⁺ , alkaline earth metal ions such as Ca ²⁺ , Mg ²⁺ , Sr ²⁺ and Ba ^2+, and transitions such as Fe, Cu and Zn. Examples include metal ions. Among these, alkali metal ions such as proton, Na ⁺ , K ⁺ , and Li ⁺ are preferable.

In ion exchange, the zeolite membrane after calcination (such as when a template is used) is replaced with an ammonium salt such as NH ₄ NO ₃ or NaNO ₃ or an aqueous solution containing ions to be exchanged, and in some cases an acid such as hydrochloric acid. What is necessary is just to perform by the method of washing with water etc. after processing at the temperature of 100 degreeC. Furthermore, you may bake at 200 to 500 degreeC as needed.
The air permeation [L / (m ² · h)] of the porous support-zeolite membrane composite (zeolite membrane composite after heat treatment) thus obtained is usually 1400 L / (m ² · h) or less, preferably Is 1000 L / (m ² · h) or less, more preferably 700 L / (m ² · h) or less, more preferably 600 L / (m ² · h) or less, more preferably 500 L / (m ² · h) or less, Particularly preferably, it is 300 L / (m ² · h) or less, most preferably 200 L / (m ² · h) or less. In lower limit of the transmission amount is not particularly limited, it is generally 0.01L / ^(m 2 · h) or more, preferably 0.1L / ^(m 2 · h) or more, more preferably 1L / ^(m 2 · h) or higher is there.

Here, the air permeation amount is the air permeation amount [L / (m ² · h)] when the zeolite membrane composite is connected to a vacuum line having an absolute pressure of 5 kPa, as will be described later.
(Hot water treatment)
In the method of the present invention, the zeolite membrane composite is immersed in water having a temperature of 40 ° C. or higher and 300 ° C. or lower for 1 hour or longer. In the present specification, the immersion of the zeolite membrane composite in water may be abbreviated as “warm water treatment”.

By the above hot water treatment, it is considered that Si—O—Si bonds generated on the surface of the zeolite by heat treatment (drying, firing, etc.) can be made into highly hydrophilic Si—OH, thereby improving the water permeation performance. It is done. In addition, it is considered that the performance of the film is improved because fine defects are repaired using amorphous silica or the like present in the defects as a raw material.
Here, the water in the hot water treatment is liquid water, and includes water that is liquid under pressure at a temperature equal to or higher than the boiling point. The pressure in this case may be an autogenous pressure or a pressurization.

  The water temperature is usually 40 ° C. or higher, preferably 60 ° C. or higher, more preferably 80 ° C. or higher, particularly preferably 100 ° C. or higher, and usually 300 ° C. or lower, preferably 200 ° C. or lower, more preferably 160 ° C. or lower. is there. If the temperature of the water is too low, the effect of making Si-O-Si bonds generated on the surface of the zeolite highly hydrophilic Si-OH and fine defects will be repaired using amorphous silica etc. present in the defects as a raw material. May not be sufficient. If the temperature of the water is too high, the zeolite may partially dissolve in the water and the zeolite membrane may be broken.

  The immersion time in water is usually 1 hour or more, preferably 5 hours or more, more preferably 7 hours or more, particularly preferably 10 hours or more, and usually 100 hours or less, preferably 50 hours or less, more preferably 30 hours. It is as follows. If the immersion time is too short, the change of the film surface does not proceed sufficiently and a sufficient effect may not be obtained. If the soaking time is too long, the zeolite may partially dissolve in water and break the zeolite.

  The zeolite membrane composite may be used as it is after being immersed in water, but may be washed with water or dried as necessary. When drying by heating, it is usually 20 ° C. or higher, preferably 40 ° C. or higher, more preferably 100 ° C. or higher, more preferably 150 ° C. or higher, usually 500 ° C. or lower, preferably 400 ° C. or lower, more preferably 300 ° C. or lower. It is. If the heating temperature is too high, the surface of the zeolite membrane may be close to the state after calcination, and the effect of the hot water treatment may be lost.

A trace amount of OH ⁻¹ ions may be actively present in the water. In that case, the OH ⁻¹ ion concentration in water is usually 0.05 mol / l or less, preferably 0.01 mol / l or less, more preferably It is 0.005 mol / l or less, usually 0.0001 mol / l or more, preferably 0.0005 mol / l or more, more preferably 0.001 mol / l or more. The presence of OH ^-1 ions in water makes it possible to obtain the same effect in a shorter time than when no OH ^-1 ions exist. If the OH ^-1 ion concentration in water is too high, the zeolite membrane is easily dissolved and broken, and strict control of the treatment time is required.

The water may contain at least one element selected from Si, Al, B, P and the like. Among these, Si and Al are preferable, and Si is particularly preferable.
In particular, when Si element is contained in water, defects existing in the film are preferably partially repaired by Si element contained in water.
The concentration of these elements is usually 0.00001% by mass or more, preferably 0.00005% by mass or more, more preferably 0.0001% by mass or more, further preferably 0.001% by mass or more, and particularly preferably 0.01% by mass. % Or more, most preferably 0.1% by mass or more, usually 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less.

When Si element is contained, it is usually 0.01% by mass or more, preferably 0.1% by mass or more, and usually 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less. .
Examples of the Si element source include alkoxysilanes such as tetraethoxysilane, tetramethoxysilane, methyltriethoxysilane, and 3-aminopropyltriethoxysilane, amorphous silica, fumed silica, colloidal silica, silica gel, sodium silicate, and silicate. Oligomers, silica sols and the like can be used, and alkoxysilane is preferable in terms of reactivity.

As the Al element source, for example, sodium aluminate, aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum oxide, alumina sol, amorphous aluminosilicate gel, aluminum alkoxide such as aluminum isopropoxide, or the like can be used.
By immersing the zeolite membrane complex in water containing Si, Al, B, P, etc., which can be constituent elements of the zeolite, and heating, the fine defects present in the zeolite membrane are caused by Si, Al, B, P in the water. The performance of the film may be improved by repairing the material as a raw material or by improving the hydrophilicity by modifying the surface of the film with an element contained in the water. If the concentration of these elements is too low, the effect is equivalent to treatment with water alone. If the concentration of these elements is too high, amorphous SiO ₂ , Al ₂ O ₃ or the like adheres to the zeolite membrane composite and the permeation flux tends to decrease.

The water may contain an acid such as an organic acid such as carboxylic acid or sulfonic acid, or an inorganic acid such as sulfuric acid or phosphoric acid. In particular, when Si is contained in water, it is preferable to contain an acid in water.
As the acid contained in water, carboxylic acid and inorganic acid are particularly preferable. As the carboxylic acid, formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, maleic acid, phthalic acid, lactic acid, citric acid, acrylic acid and the like are preferable, formic acid, acetic acid and lactic acid are more preferable, and among these, acetic acid is particularly preferable. Is preferred. As the inorganic acid, sulfuric acid, nitric acid, phosphoric acid and the like are preferable, and sulfuric acid and phosphoric acid are preferable.

The concentration of the acid contained in the water is usually 0.00001% by mass or more, preferably 0.00005% by mass or more, more preferably 0.0001% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less. More preferably, it is 2 mass% or less.
The H ⁺ concentration in water is usually 1 × 10 ⁻⁸ mol / l or more, preferably 1 × 10 ⁻⁷ mol / l.
1 or more, more preferably 1 × 10 ⁻⁵ mol / l or more, and further preferably 1 × 10 ⁻³ m.
ol / l or more, particularly preferably 0.005 mol / l or more, most preferably 0.01 mol / l or more, and usually 10 mol / l or less, preferably 5 mol / l or less, more preferably 1 mol / l or less.

In particular, when Si is contained in water, the liquidity of water is preferably acidic, and the H ⁺ concentration in water at that time is usually 0.00001 mol / l or more, more preferably 0.0001 mol / l or more, and still more preferably 0.00. 0005 mol / l or more, most preferably 0.001 mol / l or more, usually 10 mol / l or less, preferably 5 mol / l or less, more preferably 1 mol / l or less.

  The zeolite membrane composite used in the present invention is immersed in water containing an acid and heat-treated, whereby the acid present in the water is adsorbed on the fine defect portion present in the zeolite membrane, and the defect is blocked. Hydrolysis of the Si—O—Si bond on the membrane surface is promoted by the presence of an acid, and Si—OH is formed on the membrane surface to improve the hydrophilicity of the membrane, thereby improving the membrane separation performance and permeation flux. There is a case.

If the concentration of these acids is too low, the effect is equivalent to treatment with water alone. On the other hand, if the concentration of these acids is too high, the acid is adsorbed not only on the defective portion but also on the entire surface of the zeolite membrane, blocking the flow path, and the permeation flux tends to decrease.
The water may contain a polymer compound having hydrophilicity such as polyvinyl alcohol (PVA) and Nafion (registered trademark) and / or a monomer thereof.

The concentration of these hydrophilic polymer compounds and / or monomers thereof is usually 0.0.
It is 0001% by mass or more, preferably 0.00005% by mass or more, more preferably 0.0001% by mass or more, and usually 30% by mass or less, preferably 20% by mass or less, more preferably 10% by mass or less.
By immersing in water containing a hydrophilic polymer compound and / or its monomer and heat treatment, a hydrophilic polymer layer is formed on the zeolite membrane, making the zeolite membrane more hydrophilic and water. In addition to improving the permeation flux, fine defect portions present in the zeolite membrane tend to be blocked with a hydrophilic polymer to improve the separation performance. If this concentration is too low, the effect is equivalent to treatment with water alone. On the other hand, if the concentration is too high, the hydrophilic polymer layer formed on the zeolite membrane becomes thick and the permeation flux tends to decrease.

The zeolite membrane composite thus produced has excellent characteristics as described above, and can be suitably used as a membrane separation means in the separation method of the present invention.
(Separation method)
In the separation method of the present invention, a mixture of a gas or a liquid containing an organic compound is brought into contact with the porous support-zeolite membrane composite to separate a highly permeable substance from the mixture. It has characteristics. In the present invention, the same porous support-zeolite membrane composite as described above is used. The preferable ones are also the same as described above.

  In the separation method of the present invention, a gas or liquid mixture containing an organic compound is brought into contact with one side of the support side or the zeolite membrane side through an inorganic porous support provided with a zeolite membrane, and the mixture is brought into contact with the opposite side. By allowing the pressure to be lower than that of the side on which it is applied, a substance having high permeability to the zeolite membrane (a substance in the mixture having relatively high permeability) is selectively permeated from the mixture, that is, as a main component of the permeation substance. . Thereby, a highly permeable substance can be separated from the mixture. As a result, the specific organic compound can be separated and recovered or concentrated by increasing the concentration of the specific organic compound (substance in the mixture having relatively low permeability) in the mixture.

For example, in the case of a mixture of water and an organic compound, water is usually highly permeable to the zeolite membrane, so water is separated from the mixture and the organic compound is concentrated in the original mixture. A separation / concentration method called a pervaporation method (pervaporation method) or a vapor permeation method (vapor permeation method) is one embodiment of the separation method of the present invention.
The pervaporation method is a separation / concentration method in which a liquid mixture is directly introduced into a separation membrane, so that a process including separation / concentration can be simplified.

  The vapor permeation method is a separation / concentration method in which a liquid mixture is vaporized and then introduced into a separation membrane. Therefore, the vapor permeation method can be used in combination with a distillation apparatus or for separation at higher temperature and pressure. In addition, the vapor permeation method introduces the liquid mixture after vaporizing it into the separation membrane, reducing the effects of impurities contained in the supply liquid and substances that form aggregates and oligomers in the liquid state on the membrane. can do. The inorganic porous support-zeolite membrane composite obtained by the present invention can be suitably used for any method.

  In addition, when performing separation at a high temperature by the vapor permeation method, the separation performance generally decreases as the temperature increases, but the inorganic porous support-zeolite membrane composite obtained by the present invention exhibits high separation performance even at high temperatures. Can be expressed. In general, the vapor permeation method separates the liquid mixture after vaporizing it, and therefore usually the separation is performed under harsher conditions than the pervaporation method. Therefore, durability of the membrane composite is also required. The inorganic porous support-zeolite membrane composite obtained by the present invention is suitable for the vapor permeation method in addition to having durability capable of separation even under high temperature conditions.

The porous support-zeolite membrane composite exhibits high permeation performance and selectivity even when treated with a water-containing organic compound having a water content of 20% by mass or more, and exhibits performance as a separation membrane with excellent durability. Have.
The high permeation performance here indicates a sufficient throughput, for example, the permeation flux of a substance that permeates the membrane is, for example, 2-propanol or N-methyl-2-pyrrolidone having a water content of 30% by mass and water. When the mixture is permeated at a pressure difference of 1 atm (1.01 × 10 ⁵ Pa) at 70 ° C., 1 kg / (m ² · h) or more, preferably 3 kg / (m ² · h) or more Preferably, it means 5 kg / (m ² · h) or more. The upper limit of the permeation flux is not particularly limited, and is usually 20 kg / (m ² · h) or less, preferably 15 kg / (m ² · h) or less.

Further, high transmission performance can be expressed by permeance (also referred to as “permeance”). Permeance refers to the pressure normalized flux, divided by the product of membrane area, time, and water partial pressure difference. When expressed in units of permeance, as water permeance, for example, a mixture of 2-propanol or N-methyl-2-pyrrolidone having a water content of 30% by mass and water at 70 ° C., 1 atmosphere (1.01 × 10 ⁵ When permeated at a pressure difference of Pa), usually 3 × 10 ⁻⁷ mol / (m ² · s · Pa) or more, preferably 5 × 10 ⁻⁷ mol / (m ² · s · Pa) or more, more preferably Is 1 × 10 ⁻⁶ mol / (m ² · s · Pa) or more, particularly preferably 2 × 10 ⁻⁶ mol / (m ² · s · Pa) or more. The upper limit of permeance is not particularly limited, and is usually 1 × 10 ⁻⁴ mol / (m ² · s · Pa) or less, preferably 5 × 10 ⁻⁵ mol / (m ² · s · Pa) or less.

Selectivity is represented by a separation factor. The separation factor is the following index representing the selectivity generally used in membrane separation.
Separation factor = (Pα / Pβ) / (Fα / Fβ)
[Wherein Pα is the mass percent concentration of the main component in the permeate, Pβ is the mass percent concentration of the subcomponent in the permeate, Fα is the mass percent concentration in the separated mixture of the main component in the permeate, Fβ is the mass percent concentration of the component to be separated in the permeated liquid in the mixture to be separated. ]
As for the separation factor, for example, a mixture of 2-propanol or N-methyl-2-pyrrolidone having a water content of 30% by mass and water was permeated at 70 ° C. with a pressure difference of 1 atm (1.01 × 10 ⁵ Pa). In this case, it is usually 1000 or more, preferably 4000 or more, more preferably 10,000 or more, and particularly preferably 20000 or more. The upper limit of the separation factor is the case where only water is completely transmitted. In this case, the separation factor is infinite, but is preferably 10000000 or less, more preferably 1000000 or less.

When the object to be separated is a mixture of water and an organic compound (hereinafter sometimes referred to as “water-containing organic compound”), the water content in the mixture is usually 20% by mass or more, preferably 30% by mass or more, more preferably Is 45% by mass or more, usually 95% by mass or less, preferably 80% by mass or less, and more preferably 70% by mass or less.
In the separation method of the present invention, since the substance that permeates the zeolite membrane is usually water, if the water content decreases, the amount of treatment decreases, which is not efficient. On the other hand, if the water content is too high, the membrane required for concentration becomes a large area (in the case where the membrane is formed in a tubular shape, the number is increased), and the economic effect is reduced.

As a water-containing organic compound, the water content may be adjusted in advance by an appropriate water adjustment method. In this case, the preferred water content is the same as described above. Examples of the moisture adjustment method include methods known per se, such as distillation, pressure swing adsorption (PSA), temperature swing adsorption (TSA), and desiccant system.
Further, water may be further separated from the water-containing organic compound from which water has been separated by the zeolite membrane composite. Thereby, water can be separated to a higher degree and the water-containing organic compound can be further concentrated.

  Examples of organic compounds include carboxylic acids such as acetic acid, acrylic acid, propionic acid, formic acid, lactic acid, oxalic acid, tartaric acid, benzoic acid, sulfonic acid, sulfinic acid, habituric acid, uric acid, phenol, enol, and diketone type compounds. Organic acids such as thiophenol, imide, oxime, aromatic sulfonamide, primary and secondary nitro compounds; alcohols such as methanol, ethanol and isopropanol (2-propanol); ketones such as acetone and methyl isobutyl ketone Aldehydes such as acetaldehyde, ethers such as dioxane and tetrahydrofuran; organic compounds containing nitrogen such as amides such as dimethylformamide and N-methylpyrrolidone (N-containing organic compounds), esters such as acetates and acrylates Na And the like.

Among these, the effect of the inorganic porous support-zeolite membrane composite is noticeable when separating the organic acid from a mixture of organic acid and water, which can take advantage of both molecular sieve and hydrophilic characteristics. To do. A preferred example is a mixture of carboxylic acids and water, particularly preferably separation of acetic acid and water.
In addition, the organic substance in the case of separating the organic substance and water from the mixture of the organic substance other than the organic acid and water preferably has 2 or more carbon atoms, and more preferably 3 or more carbon atoms.

Among these organic substances other than organic acids, organic compounds containing at least one selected from alcohols, ethers, ketones, aldehydes, and amides are particularly desirable. Among these organic compounds, those having 2 to 10 carbon atoms are preferable, and those having 3 to 8 carbon atoms are more preferable.
Moreover, as an organic compound, the high molecular compound which can form a mixture (mixed solution) with water may be sufficient. Examples of such a polymer compound include those having a polar group in the molecule, for example, polyols such as polyethylene glycol and polyvinyl alcohol; polyamines; polysulfonic acids; polycarboxylic acids such as polyacrylic acid; Carboxylic acid esters; modified polymer compounds obtained by modifying polymers by graft polymerization, etc .; copolymerized polymer compounds obtained by copolymerization of nonpolar monomers such as olefins and polar monomers having polar groups such as carboxyl groups And the like.

  The water-containing mixture may be a mixture that forms an azeotrope, such as a mixture of water and phenol. In the separation of a mixture that forms an azeotrope, water is more selective than the separation by distillation. It is preferable in terms of well-separable surfaces. Specifically, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol and the like; mixtures of alcohols and water, ethyl acetate, ethyl acrylate, methyl methacrylate, etc .; esters and water Mixtures, formic acid, isobutyric acid, valeric acid, etc .; carboxylic acids and water mixtures; phenols, anilines, etc .; aromatic organic substances and water mixtures, acetonitrile, acrylonitrile, etc .; nitrogen-containing mixtures and water, etc. .

  Further, the water-containing organic compound may be a mixture of water and a polymer emulsion. Here, the polymer emulsion is a mixture of a surfactant and a polymer, which is usually used for adhesives, paints, and the like. Examples of the polymer used in the polymer emulsion include polyvinyl acetate, polyvinyl alcohol, acrylic resin, polyolefin, olefin-polar monomer copolymer such as ethylene-vinyl alcohol copolymer, polystyrene, polyvinyl ether, polyamide, polyester, and cellulose. Thermoplastic resins such as derivatives; thermosetting resins such as urea resins, phenol resins, epoxy resins, polyurethanes; rubbers such as natural rubber, polyisoprene, polychloroprene, butadiene copolymers such as styrene-butadiene copolymers, etc. Can be mentioned. As the surfactant, a known one may be used.

Since the zeolite membrane composite of the present invention has acid resistance, it can be effectively used for water separation from a mixture of water and an organic acid such as acetic acid and water separation for promoting esterification reaction.
The separation method of the present invention may be carried out by preparing a suitable separation device using the zeolite membrane composite and introducing a gas or liquid mixture containing an organic compound into the separation device. These separation devices can be made of a member known per se.

Hereinafter, the present invention will be described more specifically based on experimental examples. However, the present invention is not limited to the following experimental examples unless it exceeds the gist. In the following experimental examples, physical properties and separation performance were measured as follows.
(1) X-ray diffraction (XRD) measurement XRD measurement of the zeolite membrane was performed under the following conditions.
-Device name: X'PertPro MPD manufactured by PANalytical, the Netherlands
Optical system specifications Incident side: Enclosed X-ray tube (CuKα)
Soller Slit (0.04 rad)
Divergence Slit (Variable Slit
)
Sample stage: XYZ stage
Light receiving side: Semiconductor array detector (X 'Celerator)
Ni-filter
Soller Slit (0.04 rad)
Goniometer radius: 240mm
Measurement conditions X-ray output (CuKα): 45 kV, 40 mA
Scanning axis: θ / 2θ
Scanning range (2θ): 5.0-70.0 °
Measurement mode: Continuous
Reading width: 0.05 °
Counting time: 99.7 sec
Automatic variable slit (Automatic-DS): 1 mm (irradiation width)
Lateral divergence mask: 10 mm (irradiation width)
X-rays were irradiated in a direction perpendicular to the axial direction of the cylindrical tube. Also, the X-ray is not the sample table surface, but the sample table surface, out of the two lines where the cylindrical tubular membrane complex placed on the sample table and the plane parallel to the sample table surface are in contact with each other so that noise and the like are not introduced as much as possible. It was made to hit mainly on the other line above the surface.

In addition, the irradiation width was fixed to 1 mm by an automatic variable slit and measured, and Materials Data, Inc. XRD analysis software JADE 7.5.2 (Japanese version) was used to perform variable slit → fixed slit conversion to obtain an XRD pattern.
(2) Air permeation amount One end of the zeolite membrane composite was sealed, the other end was sealed and connected to a 5 kPa vacuum line, and the air flow was measured with a mass flow meter installed between the vacuum line and the zeolite membrane composite. The flow rate was measured and the air permeation amount [L / (m ² · h)] was obtained. As the mass flow meter, 8300 manufactured by KOFLOC, for N ₂ gas, and a maximum flow rate of 500 ml / min (20 ° C., converted to 1 atm) were used. When the mass flow meter display on the KOFLOC 8300 is 10 ml / min (20 ° C, converted to 1 atm) or less, Lintec MM-2100M, for Air gas, maximum flow rate 20 ml / min (converted to 0 ° C, 1 atm) It measured using.

(3) SEM-EDX measurement SEM-EDX measurement of the zeolite membrane was performed under the following conditions.
-Device name: SEM: FE-SEM Hitachi: S-4800
EDX: EDAX Genesis
・ Acceleration voltage: 10 kV
The entire field of view (25 μm × 18 μm) at a magnification of 5000 was scanned, and X-ray quantitative analysis was performed.

(4) SEM measurement SEM measurement was performed based on the following conditions.
Device name: SEM: FE-SEM Hitachi: S-4100
・ Acceleration voltage: 10 kV
(5) Pervaporation method FIG. 1 shows a schematic diagram of an apparatus used for the pervaporation method. In FIG. 1, the inside of the zeolite membrane composite 5 is depressurized by a vacuum pump 9, and the pressure difference from the outside in contact with the liquid 4 to be separated is about 1 atm. Due to this pressure difference, the permeated water in the liquid to be separated 4 permeates and permeates into the zeolite membrane composite 5. The permeated material is collected by the trap 7. On the other hand, the organic compound in the liquid to be separated 4 stays outside the zeolite membrane composite 5.

At regular intervals, the permeate collected in the trap 7 is weighed and analyzed, and the composition of the liquid 4 to be separated is analyzed. Using these values, the separation factor, permeation flux, water permeance, etc. Was calculated as described above. The composition analysis was performed by gas chromatography.
(6) Vapor Permeation Method FIG. 2 shows a schematic diagram of an apparatus used for the vapor permeation method. In FIG. 2, the liquid to be separated 10 is sent to the vaporizer 12 at a predetermined flow rate by the liquid feed pump 11, and the entire amount is vaporized by heating in the vaporizer 12 to become a gas to be separated. The gas to be separated is introduced into the zeolite membrane composite module 14 in the thermostatic chamber 13 and supplied to the outside of the zeolite membrane composite. The zeolite membrane composite module 14 is obtained by housing a zeolite membrane composite in a housing. The inside of the zeolite membrane composite is depressurized by the vacuum pump 18, and the pressure difference with the gas to be separated is about 1 atm. Although not shown, the inner pressure can be measured with a Pirani gauge. Due to this pressure difference, the permeated water in the gas to be separated permeates the zeolite membrane composite 14. The permeated substance is collected by the permeate collecting trap 16. On the other hand, components that have not permeated in the gas to be separated are liquefied and collected by the liquid collecting trap 15.

At regular time intervals, the permeate collected in the permeate trap 16 is weighed and the composition is analyzed. Using these values, the separation factor, permeation flux, water permeance, etc. for each time are measured. Calculated as follows. The composition analysis was performed by gas chromatography.
(7) XPS Measurement XPS (X-ray photoelectron spectroscopy) measurement on the zeolite membrane surface was performed under the following conditions.
・ Device name: Quantum2000 manufactured by PHI
・ X-ray source: Monochromatic Al-Kα, output 16 kV-34 W (X-ray generation area 170 μmφ) ・ Charge neutralization: combined use of electron gun (5 μA) and ion gun (10 V) ・ Spectroscopy system: pulse energy 187.85 eV @ wide Spectrum
58.70 eV @ narrow spectrum (Na1s, Al2p, Si2p, K2p, S2p)
29.35eV@wide spectrum (C1s, O1s, Si2p)
Measurement area: Spot irradiation (irradiation area <340 μmφ)
Extraction angle: 45 ° (from surface)
(Comparative Example 1)
The inorganic porous support CHA-type zeolite membrane composite was produced by hydrothermal synthesis of CHA-type zeolite directly on the inorganic porous support as follows.

The following was prepared as a reaction mixture for hydrothermal synthesis.
Aluminum hydroxide (containing 53.5% by weight of Al ₂ O ₃ , manufactured by Aldrich) mixed with 10.5 g of 1 mol / L-NaOH aqueous solution, 7.0 g of 1 mol / L-KOH aqueous solution and 100.5 g of water 88 g was added, stirred and dissolved to obtain a transparent solution. As an organic template, 2.36 g of an aqueous solution of N, N, N-trimethyl-1-adamantanammonium hydroxide (hereinafter referred to as “TMADAOH”) (containing 25% by weight of TMADAOH, manufactured by Seychem) was added, and colloidal silica was further added. 10.5 g (Nissan Chemical Snow Tech-40) was added and stirred for 2 hours to obtain a reaction mixture.

The composition (molar ratio) of this reaction mixture was SiO ₂ / Al ₂ O ₃ / NaOH / KOH / H ₂ O / TMADAOH = 1 / 0.066 / 0.15 / 0.1 / 100 / 0.04, SiO 2 ₂ / Al ₂ O ₃ = 15.
As the inorganic porous support, a porous alumina tube (outer diameter 12 mm, inner diameter 9 mm) was cut to a length of 80 mm, washed with an ultrasonic cleaner and dried.

As a seed crystal, the gel composition (molar ratio) of SiO ₂ / Al ₂ O ₃ / NaOH / KOH / H ₂ O / TMADAOH = 1 / 0.033 / 0.1 / 0.06 / 40 / 0.07 is 160. ° C, 2
A CHA-type zeolite crystallized by hydrothermal synthesis for days was used. The seed crystal grain size was about 1 μm.
The support was immersed in a dispersion obtained by dispersing the seed crystal in 1% by mass of water for a predetermined time, and then dried at 100 ° C. for 5 hours to adhere the seed crystal. The mass of the attached seed crystal was 2.2 g / m ² .

The support to which the seed crystal was attached was immersed in a Teflon (registered trademark) inner cylinder (200 ml) containing the above reaction mixture in the vertical direction to seal the autoclave, and left standing at 160 ° C. for 48 hours. Heated under autogenous pressure. After the elapse of a predetermined time, after cooling, the support-zeolite membrane complex was taken out of the reaction mixture, washed and dried at 100 ° C. for 5 hours or more.
The zeolite membrane composite before template firing was fired in an electric furnace at 500 ° C. for 5 hours. The weight of the CHA zeolite crystallized on the support, which was obtained from the difference between the weight of the membrane composite after firing and the weight of the support, was 130 g / m ² .

The air permeation amount of the zeolite membrane composite after calcination was 190 L / (m ² · h). When XRD of the produced membrane was measured, it was found that CHA-type zeolite was produced.
From the XRD pattern, (the intensity of the peak near 2θ = 17.9 °) / (the intensity of the peak near 2θ = 20.8 °) = 3.5, and the XRD of the CHA-type zeolite of the powder used for the seed crystal The peak intensity around 2θ = 17.9 ° was remarkably larger than that in FIG. 2, and the orientation to the (1,1,1) plane in the rhombohedral setting was estimated.

As a result of observing the inorganic porous support-zeolite membrane composite cut into strips by SEM, it was found that crystals were densely formed on the surface.
The SiO ₂ / Al ₂ O ₃ molar ratio of the zeolite membrane measured by SEM-EDX was 17.
Using the obtained inorganic porous support-CHA type zeolite membrane composite, water was selectively selected from a water / N-methyl-2-pyrrolidone mixed solution (30/70% by weight) at 70 ° C. by a pervaporation method. Separation to be permeated through.

The permeation results after 3 hours were as follows: permeation flux: 7.9 kg / (m ² · h), separation factor: 2200, and the concentration of water in the permeate was 99.89% by weight. The water permeance was 5.8 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 1.
(Example 1)
The inorganic porous support-CHA type zeolite membrane composite produced under the same conditions as in Comparative Example 1 was immersed vertically in a Teflon (registered trademark) inner cylinder containing about 150 g of demineralized water, and the autoclave was sealed. The mixture was heated at 120 ° C. for 5 hours under an autogenous pressure, allowed to cool after a predetermined time, and then the support-zeolite membrane composite was taken out from the reaction mixture. Hereinafter, this treatment is referred to as “warm water treatment 1”.

Using an inorganic porous support-CHA-type zeolite membrane composite subjected to warm water treatment 1, water is obtained from a water / N-methyl-2-pyrrolidone mixed solution (30/70% by weight) at 70 ° C. by a pervaporation method. Separation with selective permeation was performed.
After 3 hours, the permeation results were as follows: permeation flux: 7.8 kg / (m ² · h), separation factor: 25100, concentration of water in the permeate: 99.99% by weight. In terms of water permeance, it was 5.7 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 1.

From the results of Comparative Example 1 and Example 1, it can be seen that the separation factor was improved about 11 times by applying the hot water treatment 1.
(Comparative Example 2)
An inorganic porous support-CHA type zeolite membrane composite was prepared in the same manner as in Comparative Example 1 except that a mullite tube PM (external diameter: 12 mm, internal diameter: 9 mm) manufactured by Nikkato was used as the inorganic porous support.

The weight of the CHA-type zeolite crystallized on the support, determined from the difference between the weight of the calcined zeolite membrane complex and the weight of the support, was 140 g / m ² .
The air permeation amount of the zeolite membrane composite after calcination was 50 L / (m ² · min).
When XRD of the produced membrane was measured, it was found that CHA-type zeolite was produced.

From the XRD pattern, (peak intensity around 2θ = 17.9 °) / (2θ = 20.8 °)
The intensity of the peak in the vicinity of 2θ = 17.9 ° is significantly larger than the XRD of the powdered CHA-type zeolite used for the seed crystal, which is (1,1) in the rhombohedral setting. 1) Orientation to the plane was estimated.
As a result of observing the inorganic porous support-CHA-type zeolite membrane composite cut into strips by SEM, crystals were densely formed on the surface.

The SEM-EDX, the results of measuring the _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane, _SiO 2 / _Al 2 _{O 3} molar ratio of the produced film was 17.
Using the obtained inorganic porous support-CHA type zeolite membrane composite, water was selectively selected from a water / N-methyl-2-pyrrolidone mixed solution (30/70% by weight) at 70 ° C. by a pervaporation method. Separation to be permeated through.

The permeation performance after 3 hours was as follows: permeation flux: 4.1 g / (m ² · h), separation factor: 2800, concentration of water in the permeate: 99.91 wt%. The water permeance was 3.0 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 1.
(Example 2)
The inorganic porous support-CHA type zeolite membrane composite produced under the same conditions as in Comparative Example 2 was subjected to hot water treatment 1 in the same manner as in Example 2.

A water / N-methyl-2-pyrrolidone mixed solution (30/70) at 70 ° C. by a pervaporation method using an inorganic porous support-CHA-type zeolite membrane composite subjected to hot water treatment 1.
(% By weight) was selectively separated from water.
After 3 hours, the permeation results were as follows: permeation flux: 4.3 kg / (m ² · h), separation factor: 25100, concentration of water in the permeate: 99.99% by weight. The water permeance was 3.1 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 1.

From the results of Comparative Example 2 and Example 2, it can be seen that the separation factor was improved about 9 times by applying the hot water treatment 1.
(Comparative Example 3)
An inorganic porous support-CHA type zeolite membrane composite was prepared in the same manner as in Comparative Example 2 except that the following was prepared as a reaction mixture for hydrothermal synthesis.

The reaction mixture for hydrothermal synthesis was prepared by mixing 8.8 g of a 1 mol / L-NaOH aqueous solution, 17.6 g of a 1 mol / L-KOH aqueous solution and 90.2 g of water with aluminum hydroxide (Al ₂ O ₃
1.68 g (containing 53.5% by weight, manufactured by Aldrich) was added and dissolved by stirring to obtain a transparent solution. To this, 2.99 g of TMADAOH aqueous solution (containing 25% by weight of TMADAOH, manufactured by Sechem Co.) was added, and further 13.2 g of colloidal silica (Snowtech-40 manufactured by Nissan Chemical Co., Ltd.) was added and stirred for 2 hours to prepare.

The composition (molar ratio) of this reaction mixture was SiO ₂ / Al ₂ O ₃ / NaOH / KOH / H ₂ O / TMADAOH = 1 / 0.1 / 0.1 / 0.2 / 80 / 0.04, SiO ₂ / Al ₂ O ₃ = 10.
The weight of the CHA-type zeolite crystallized on the support, determined from the difference between the weight of the calcined zeolite membrane composite and the weight of the support, was 90 g / m ² .

The air permeation amount of the zeolite membrane composite after calcination was 440 L / (m ² · min).
When XRD of the produced membrane was measured, it was found that CHA-type zeolite was produced.
From the XRD pattern, (peak intensity around 2θ = 17.9 °) / (2θ = 20.8 °)
The intensity of the peak in the vicinity) is 0.7, and the XR of the powdered CHA zeolite used for the seed crystal
Compared to D, the intensity of the peak near 2θ = 17.9 ° was significantly larger, and the orientation to the (1,1,1) plane in the rhombohedral setting was estimated.

As a result of observing the inorganic porous support-CHA-type zeolite membrane composite cut into strips by SEM, crystals were densely formed on the surface.
Using the obtained inorganic porous support-CHA type zeolite membrane composite, separation was carried out by selectively permeating water from a 70 ° C. water / acetic acid mixed solution (50/50 wt%) by a pervaporation method. .

The permeation results after 5 hours were as follows: permeation flux: 5.4 kg / (m ² · h), separation factor: 400, and water concentration in the permeate: 99.76% by weight. The water permeance was 3.4 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 1.
(Example 3)
The inorganic porous support-CHA type zeolite membrane composite produced under the same conditions as in Comparative Example 3 was subjected to hot water treatment under the same conditions as in Example 1 except that the treatment time was 6 hours. Hereinafter, this treatment is referred to as “warm water treatment 2”.

Using an inorganic porous support-CHA-type zeolite membrane composite subjected to warm water treatment 2, water is selectively permeated from a 70 ° C. water / acetic acid mixed solution (50/50 wt%) by a pervaporation method. Separation was performed.
The permeation performance after 5 hours was as follows: permeation flux: 5.7 kg / (m ² · h), separation factor: 2000, and water concentration in the permeate: 99.95% by weight. The water permeance was 3.6 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 1.

From the results of Comparative Example 3 and Example 3, it can be seen that the separation factor was improved about 5 times by applying the hot water treatment 2.
(Reference Example 1)
Using an inorganic porous support-CHA-type zeolite membrane composite produced under the same conditions as in Comparative Example 2, water was selectively selected from a 70 ° C. water / acetic acid mixed solution (50/50 wt%) by a pervaporation method. The permeation separation was performed in the same manner as in Comparative Example 1.

The permeation results after 5 hours were as follows: permeation flux: 4.1 kg / (m ² · h), separation factor: 600, and water concentration in the permeate: 99.82% by weight. The water permeance was 2.6 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 2.
(Reference Example 2)
An inorganic porous support-CHA type zeolite membrane composite produced under the same conditions as in Comparative Example 2 was immersed in a Teflon (registered trademark) inner cylinder containing about 150 g of 0.1 mol / l KOH aqueous solution in the vertical direction. The autoclave was sealed, heated at 70 ° C. for 2 hours under an autogenous pressure, and after a predetermined time had passed and allowed to cool, the support-zeolite membrane complex was taken out of the reaction mixture. Hereinafter, this treatment is referred to as “alkali treatment”.

Separation by selectively permeating water from a water / acetic acid mixed solution (50/50% by weight) at 70 ° C. by pervaporation method using an inorganic porous support-CHA type zeolite membrane composite subjected to alkali treatment Was carried out in the same manner as in Example 1.
The permeation performance after 5 hours was as follows: permeation flux: 3.0 kg / (m ² · h), separation factor: 200, and water concentration in the permeate: 99.40% by weight. In terms of water permeance, it was 1.9 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 2.

From the results of Reference Example 1 and Reference Example 2, it can be seen that the separation factor was reduced to about 1/3 and the permeation flux was reduced by performing the alkali treatment at a concentration of 0.1 mol / l. It is estimated that a part of the film has been altered by the alkali treatment.
(Comparative Example 4)
An inorganic porous support-CHA-type zeolite membrane composite was produced under the same conditions as in Comparative Example 2. The SEM-EDX, the results of measuring the _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane, _SiO 2 / _Al 2 _{O 3} molar ratio of the produced film was 17. Results of the measurement of the _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface by XPS, _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface was 36.2. Example of separation by selectively permeating water from water / acetic acid mixed solution (5/95% by weight) at 90 ° C. by pervaporation method using the obtained inorganic porous support-CHA type zeolite membrane composite 1 was performed.

The permeation results after 5.5 hours were as follows: permeation flux: 1.3 kg / (m ² · h), separation factor: 400, and water concentration in the permeate: 95.75% by weight. The water permeance was 1.5 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 3.
Example 4
An inorganic porous support-CHA-type zeolite membrane composite was produced under the same conditions as in Comparative Example 2. The SiO ₂ / Al ₂ O ₃ ratio in the bulk of this inorganic porous support-CHA type zeolite membrane composite was 17 as measured by SEM-EDX. Results of the measurement of the _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface by XPS, _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface was 36.2.

  This inorganic porous support-CHA type zeolite membrane composite is made of Teflon (registered trademark) containing 135 g of demineralized water, 2.5 g of tetraethoxysilane (hereinafter sometimes abbreviated as TEOS) and 1.4 g of sulfuric acid. The autoclave was sealed by immersing in a vertical direction in a cylinder, heated at 100 ° C. for 20 hours under an autogenous pressure, allowed to cool after a predetermined time, and the support-zeolite membrane composite was taken out and washed with demineralized water. . Hereinafter, this treatment is referred to as “warm water treatment 3”.

The pH of the treatment liquid used for the hot water treatment 3 was 1.0, the H ⁺ concentration was 0.1 mol / l, and the Si content was 0.24% by mass.
The SiO ₂ / Al ₂ O ₃ molar ratio on the zeolite membrane surface of the inorganic porous support-CHA type zeolite membrane composite subjected to the hot water treatment 3 was measured by XPS to be 109.8.
_SiO 2 / _Al 2 O the film surface after the hot water treatment 3 compared to the _SiO 2 / _Al 2 _{O 3} ratio in the bulk of the front of the inorganic porous support -CHA type zeolite membrane composite for performing hot water treatment 3 _{The 3} ratio was increasing. Therefore, it was estimated that the zeolite membrane surface was modified with silica.

Water is selectively permeated from a 90 ° C. water / acetic acid mixed solution (5/95 wt%) by the pervaporation method using the inorganic porous support-CHA type zeolite membrane composite subjected to the hot water treatment 3. Separation was performed as in Example 1.
The permeation results after 5 hours were as follows: permeation flux: 0.92 kg / (m ² · h), separation factor: 17900, concentration of water in the permeate: 99.89% by weight. The water permeance was 1.2 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 3.

From the comparison between Comparative Example 4 and Example 4, it can be seen that the “hot water treatment 3” improved the separation factor by 45 times.
(Example 5)
An inorganic porous support-CHA-type zeolite membrane composite was produced under the same conditions as in Comparative Example 2. The SiO ₂ / Al ₂ O ₃ ratio in the bulk of this inorganic porous support-CHA type zeolite membrane composite was 17 as measured by SEM-EDX. This inorganic porous support-CHA type zeolite membrane composite was immersed vertically in a Teflon (registered trademark) inner cylinder containing 135 g of demineralized water, 2.5 g of tetraethoxysilane (TEOS) and 1.62 g of acetic acid. The autoclave was sealed, heated at 100 ° C. for 20 hours under an autogenous pressure, allowed to cool after a predetermined time, and then the support-zeolite membrane composite was taken out and washed with demineralized water. Hereinafter, this treatment is referred to as “warm water treatment 4”. The pH of the treatment solution used for the hot water treatment 4 was 2.9, the H ⁺ concentration was 0.001 mol / l, and the Si content was 0.24% by mass.

The SiO ₂ / Al ₂ O ₃ molar ratio of the zeolite membrane surface of the inorganic porous support-CHA type zeolite membrane composite subjected to hot water treatment 4 was measured by XPS to be 91.2.
_SiO 2 / _Al 2 O before the inorganic porous support -CHA type zeolite membrane _SiO 2 / _Al 2 _{O 3} ratio film surface after the hot water treatment 4 compared to the composite body of bulk performing hot water treatment 4 _{The 3} ratio was large. Therefore, it was estimated that the zeolite membrane surface was modified with silica.

Water is selectively permeated from a 90 ° C. water / acetic acid mixed solution (5/95% by weight) by a pervaporation method using the inorganic porous support-CHA type zeolite membrane composite subjected to hot water treatment 4. Separation was performed as in Example 1.
The permeation results after 5 hours were as follows: permeation flux: 1.2 kg / (m ² · h), separation factor: 210000, and water concentration in the permeate: 99.99 wt%. The water permeance was 1.7 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 3.

From the comparison between Comparative Example 4 and Example 5, it can be seen that the “hot water treatment 4” improved the separation factor by a factor of 500.
(Comparative Example 5)
An inorganic porous support-CHA-type zeolite membrane composite was produced under the same conditions as in Comparative Example 2. By SEM-EDX, the results of measuring the _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane, _SiO 2 / _Al 2 _{O 3} molar ratio of the produced film was 17. Results of the measurement of the _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface by XPS, _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface was 36.2. Separation of selectively permeating water from a 90 ° C. water / acetic acid mixed solution (10/90 wt%) by the pervaporation method using the obtained inorganic porous support-CHA type zeolite membrane composite 1 was performed.

The permeation performance after 5 hours was as follows: permeation flux: 1.8 kg / (m ² · h), separation factor: 1900, concentration of water in the permeate: 99.49% by weight. The water permeance was 1.3 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 3.
(Example 6)
An inorganic porous support-CHA-type zeolite membrane composite was produced under the same conditions as in Comparative Example 2. The SiO ₂ / Al ₂ O ₃ ratio in the bulk of this inorganic porous support-CHA type zeolite membrane composite was 17 as measured by SEM-EDX. Results of the measurement of the _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface by XPS, _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface was 36.2.

  This inorganic porous support-CHA type zeolite membrane composite was immersed vertically in a Teflon (registered trademark) inner cylinder containing 135 g of demineralized water, 2.5 g of tetraethoxysilane (TEOS) and 4.7 g of phosphoric acid. The autoclave was sealed, heated at 100 ° C. for 20 hours under an autogenous pressure, allowed to cool after a predetermined time, and then the support-zeolite membrane composite was taken out and washed with demineralized water. Hereinafter, this treatment is referred to as “warm water treatment 5”.

The pH of the treatment liquid used for the hot water treatment 5 was 1.3, the H ⁺ concentration was 0.05 mol / l, and the Si content was 0.24% by mass.
The SiO ₂ / Al ₂ O ₃ molar ratio on the zeolite membrane surface of the inorganic porous support-CHA type zeolite membrane composite subjected to hot water treatment 5 was measured by XPS to be 90.0.
S in bulk of inorganic porous support-CHA type zeolite membrane composite before performing hot water treatment 5
Compared to the iO ₂ / Al ₂ O ₃ ratio, the SiO ₂ / Al ₂ O ₃ ratio on the film surface after the hot water treatment 5 was increased. Therefore, it was estimated that the zeolite membrane surface was modified with silica.

Water is selectively permeated from a 90 ° C. water / acetic acid mixed solution (10/90% by weight) by a pervaporation method using an inorganic porous support-CHA type zeolite membrane composite subjected to hot water treatment 5. Separation was performed as in Example 1.
The permeation results after 5 hours were a permeation flux of 1.7 kg / (m ² · h), a separation factor of 99000, and a water concentration in the permeate: 99.99% by weight. The water permeance was 1.3 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 3.
From the comparison between Comparative Example 5 and Example 6, it can be seen that the “hot water treatment 5” improved the separation factor by 50 times.

(Example 7)
An inorganic porous support-CHA-type zeolite membrane composite was produced under the same conditions as in Comparative Example 2. The obtained inorganic porous support-CHA-type zeolite membrane composite was immersed vertically in a Teflon (registered trademark) inner cylinder containing 134 g of desalted water and colloidal silica Snowtex 40: 1.8 g manufactured by Nissan Chemical. The autoclave was sealed, heated at 100 ° C. for 21 hours under an autogenous pressure, allowed to cool after a predetermined time, and then the support-zeolite membrane complex was taken out and washed with demineralized water. Hereinafter, this treatment is referred to as “warm water treatment 6”. The Si content of the hot water treatment 6 was 0.25% by mass.

Separation in which water is selectively permeated from a 90 ° C. water / acetic acid mixed solution (10/90 wt%) by a pervaporation method using an inorganic porous support-CHA type zeolite membrane composite subjected to hot water treatment 6 Was performed in the same manner as in Comparative Example 1.
The permeation performance after 5 hours was as follows: permeation flux: 2.3 kg / (m ² · h), separation factor: 91000, concentration of water in the permeate: 99.99% by weight. The water permeance was 1.6 × 10 ⁻⁶ mol / (m ² · s · Pa).
From the comparison between Comparative Example 5 and Example 7, it can be seen that the “hot water treatment 6” improved the separation factor by 48 times.

(Comparative Example 6)
An inorganic porous support-CHA type zeolite membrane composite was produced under the same conditions as in Comparative Example 1. The SEM-EDX, the results of measuring the _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane, _SiO 2 / _Al 2 _{O 3} molar ratio of the produced film was 17. Results of the measurement of the _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface by XPS, _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface was 32.4. Separation of selectively permeating water from a 75 ° C. water / phenol mixed solution (10/90 wt%) by pervaporation using the obtained inorganic porous support-CHA type zeolite membrane composite 1 was performed. The permeation results after 3 hours were as follows: permeation flux: 5.8 kg / (m ² · h), separation factor: 700, water concentration in the permeate: 98.78% by weight, phenol concentration: 1.22% %Met. The water permeance was 2.9 × 10 ⁻⁶ mol / (m ² · s · Pa).

(Example 8)
A hot water treatment was carried out under the same conditions as in Example 1 except that the treatment temperature was set to 100 ° C. and the treatment time was set to 19 hours to produce an inorganic porous support-CHA type zeolite membrane composite produced under the same conditions as in Comparative Example 1. gave. Hereinafter, this treatment is referred to as “warm water treatment 7”.
Separation in which water is selectively permeated from a 75 ° C. water / phenol mixed solution (10/90 wt%) by a pervaporation method using an inorganic porous support-CHA type zeolite membrane composite subjected to hot water treatment 7 Was performed in the same manner as in Comparative Example 1. The permeation results after 3 hours were as follows: permeation flux: 5.8 kg / (m ² · h), separation factor: 3200, concentration of water in the permeate: 99.72% by weight,
The phenol concentration was 0.28% by weight. The water permeance was 3.0 × 10 ⁻⁶ mol / (m ² · s · Pa).

Example 9
An inorganic porous support-CHA type zeolite membrane composite was produced under the same conditions as in Comparative Example 1. The SEM-EDX, the results of measuring the _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane, _SiO 2 / _Al 2 _{O 3} molar ratio of the produced film was 17. Results of the measurement of the _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface by XPS, _SiO 2 / _Al 2 _{O 3} molar ratio of the zeolite membrane surface was 32.4.

The obtained inorganic porous support-CHA type zeolite membrane composite was immersed vertically in a Teflon (registered trademark) inner cylinder containing 135 g of demineralized water, 2.5 g of tetraethoxysilane (TEOS) and 4.05 g of acetic acid. Then, the autoclave was sealed, heated at 100 ° C. for 20 hours under an autogenous pressure, allowed to cool after a predetermined time, and then the support-zeolite membrane composite was taken out and washed with demineralized water. Hereinafter, this treatment is referred to as “warm water treatment 8”. The pH of the treatment solution used for the hot water treatment 8 was 2.8, the H ⁺ concentration was 0.0016 mol / l, and the Si content was 0.24% by mass.

The SiO ₂ / Al ₂ O ₃ molar ratio on the zeolite membrane surface of the inorganic porous support-CHA type zeolite membrane composite subjected to the hot water treatment 8 was measured by XPS to be 60.4.
_SiO 2 / _Al 2 O before the inorganic porous support -CHA type zeolite membrane _SiO 2 / _Al 2 _{O 3} ratio film surface after the hot water treatment 8 compared with the composite material of the bulk of performing hot water treatment 8 _{The 3} ratio was increasing. Therefore, it was estimated that the zeolite membrane surface was modified with silica.

Water is selectively permeated from a 75 ° C. water / phenol mixed solution (10/90 wt%) by a pervaporation method using an inorganic porous support-CHA type zeolite membrane composite subjected to hot water treatment 8. Separation was performed as in Comparative Example 1.
The permeation results after 3 hours were as follows: permeation flux: 5.2 kg / (m ² · h), separation factor: 75000, water concentration in the permeate: 99.99 wt%, phenol concentration was 0.01 wt. %Met. The water permeance was 2.7 × 10 ⁻⁶ mol / (m ² · s · Pa). The evaluation results are shown in Table 3.

From a comparison between Comparative Example 6 and Example 8, it can be seen that the separation factor was improved by a factor of 5 by performing the warm water treatment with “warm water treatment 7”.
Moreover, it can be seen from the comparison between Comparative Example 6 and Example 9 that the separation factor was improved 100 times by performing the warm water treatment in the presence of the Si element by “warm water treatment 8”.

(Example 10)
An inorganic porous support-CHA-type zeolite membrane composite was produced under the same conditions as in Comparative Example 2. The obtained inorganic porous support-CHA type zeolite membrane composite was subjected to hot water treatment 7. Separation in which water is selectively permeated from a 75 ° C. water / phenol mixed solution (10/90 wt%) by a pervaporation method using an inorganic porous support-CHA type zeolite membrane composite subjected to hot water treatment 7 Was performed in the same manner as in Comparative Example 1. The permeation performance after 3 hours was as follows: permeation flux: 3.6 kg / (m ² · h), separation factor: 90000, and water concentration in the permeate: 99.99 wt%. The water permeance was 1.8 × 10 ⁻⁶ mol / (m ² · s · Pa).

  According to Example 10, even when a mullite tube was used, a high separation factor was shown with respect to the water / phenol mixture which is an azeotropic mixture.

(Example 11)
An inorganic porous support-CHA-type zeolite membrane composite was produced under the same conditions as in Comparative Example 2. The obtained inorganic porous support-CHA-type zeolite membrane composite was immersed in a Teflon (registered trademark) inner cylinder containing 130 g of demineralized water and 2.5 g of tetraethoxysilane (TEOS) in the vertical direction to obtain an autoclave. Sealed, heated at 100 ° C. for 24 hours under an autogenous pressure, allowed to cool after a predetermined time, and then the support-zeolite membrane composite was taken out and washed with demineralized water. The washed support-zeolite membrane composite was subjected to heat treatment at 170 ° C. for 1 hour in the air as a drying treatment. Hereinafter, this treatment is referred to as “warm water treatment 9”. A water / acetic acid mixed solution (10/90 wt%) is obtained by vapor permeation using the inorganic porous support-CHA type zeolite membrane composite subjected to the warm water treatment 9. Separation allowing selective permeation of water was performed. The inorganic porous support-CHA-type zeolite membrane composite is placed in a constant temperature bath at 130 ° C., and the water / acetic acid mixed solution is sent to the vaporizer at a flow rate of 0.8 cm ³ / min to vaporize the entire amount. The inorganic porous support-CHA type zeolite membrane composite was supplied. The permeation results after 1.5 hours were a permeation flux: 0.61 kg / (m ² · h), a separation factor: 7800, and a water concentration in the permeate: 99.89% by weight. The water permeance was 3.4 × 10 ⁻⁷ mol / (m ² · s · Pa).

  Example 11 showed that the zeolite membrane composite obtained by the production method of the present invention was also suitable for separation by the vapor permeation method.

  The present invention can be used in any industrial field. For example, water is separated from a water-containing organic compound such as a chemical plant, a fermentation plant, a precision electronic component factory, a battery manufacturing factory, etc. It can be particularly suitably used in a required field.

DESCRIPTION OF SYMBOLS 1 Stirrer 2 Hot water bath 3 Stirrer 4 Liquid to be separated 5 Zeolite membrane composite 6 Pirani gauge 7 Permeate collection trap 8 Cold trap 9 Vacuum pump 10 Liquid to be separated 11 Liquid feed pump 12 Vaporizer 13 Constant temperature bath 14 Zeolite membrane composite Body module 15 Trap for collecting separated liquid 16 Trap for collecting permeate 17 Cold trap 18 Vacuum pump

Claims (11)

A zeolite membrane containing a zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 5 or more is formed on a porous support by hydrothermal synthesis to form a zeolite membrane composite, and the zeolite membrane composite is heated to a temperature of 50 ° C. or higher. in after heat treatment, only the following water 300 ° C. temperature of 40 ° C. or higher, or a porous support, characterized in that immersing least 1 hour in water containing Si more than 20 wt% - the manufacturing method of the zeolite membrane composite .   The method according to claim 1, wherein the amount of Si contained in the water is 0.01% by mass or more. Including more acid water containing the Si, A method according to claim 2.   The method according to claim 3, wherein the acid is one of an inorganic acid, a carboxylic acid, and a sulfonic acid.   The method according to claim 3 or 4, wherein the acid is one of sulfuric acid, nitric acid, phosphoric acid, acetic acid, formic acid, and lactic acid.   The method according to claim 1, wherein the heat treatment is baking.   The method according to any one of claims 1 to 6, wherein the immersion in water is performed in a heatable container that can be sealed. The method of any one of Claims 1-7 whose OH- ¹ ion concentration in water is 0.05 mol / L or less. The method according to any one of claims 2 to 7, wherein the H ⁺ ion concentration in water is 0.00001 mol / L or more.   The method according to any one of claims 1 to 9, wherein heat treatment is further performed after immersion in water. A gas or liquid mixture containing an organic substance is brought into contact with the porous support-zeolite membrane composite produced by the method according to any one of claims 1 to 10 , and the mixture is highly permeable. A separation method characterized by permeating and separating a substance.

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