JP6845753B2 - Zeolite membrane complex - Google Patents

Description

The present invention relates to a zeolite membrane composite, and more particularly, a zeolite membrane composite used for separating a specific component from a gas mixture composed of a plurality of components, wherein the zeolite membrane has specific physicochemical properties. The present invention relates to a zeolite membrane composite containing zeolite and formed on an inorganic porous support, and a method for separating or concentrating a gas mixture using the zeolite membrane composite as a separation means.

Gas separation / purification methods include membrane separation method, adsorption separation method, absorption separation method, distillation separation method, and deep cold separation method, but the membrane separation method involves almost no phase change during gas separation. This is a method of separating by the speed difference of the gas passing through the membrane using the pressure difference as the driving energy. Compared to other gas separation / purification methods, the membrane separation method is easier to handle and the equipment scale is relatively small, so it is possible to separate and concentrate the target gas at low cost and energy saving.

As a method of gas separation by a membrane, a method using a polymer membrane has been proposed since the 1970s. However, while the polymer film has a characteristic of being excellent in processability, there is a problem that the polymer film deteriorates due to heat, chemical substances, and pressure, and the performance deteriorates.
In recent years, various inorganic films having good chemical resistance, oxidation resistance, heat stability, and pressure resistance have been proposed in order to solve these problems. Among them, zeolite has regular pores of sub-nanometers, and therefore functions as a molecular sieve, so that it can selectively permeate specific molecules and is expected to exhibit high separation performance.

Specific examples of mixed gas membrane separation are carbon dioxide and nitrogen, carbon dioxide and methane, hydrogen and hydrocarbons, hydrogen and oxygen, in the separation of gases emitted from thermal power plants and petrochemical industries.
Separation of hydrogen and carbon dioxide, nitrogen and oxygen, paraffin and olefin, etc. Zeolite membranes for gas separation that can be used include A-type membranes, FAU membranes, MFI membranes, SAPO-34 membranes, and DD.
Zeolite membranes such as R membranes are known.

The A-type zeolite membrane is easily affected by moisture, it is difficult to form a membrane without crystal gaps, and the separation performance is not high. The FAU membrane has zeolite pores of 0.6 to 0.8 nm, and is large enough for two gas molecules to enter the zeolite pores. This membrane is suitable for the separation of molecules having and not having adsorption properties to zeolite pores, for example, separation of carbon dioxide and nitrogen. However, non-adsorptive molecules are difficult to separate and have a narrow range of application. The pore size of the MFI membrane is 0.
It is 55 nm, and the pores are slightly large for the separation of gas molecules, and the separation performance is not high.

In addition, separation of carbon dioxide and methane is desired in natural gas purification plants and plants that generate biogas by methane fermentation of kitchen waste, etc., but zeolite is used as a zeolite membrane that separates these well. DDR using the molecular sieving function (Patent Document 1)
, SAPO-34 (Non-Patent Document 1) and SSZ-13 (Non-Patent Document 2) are known as films having good performance.

Japanese Unexamined Patent Publication No. 2004-105942

Shiguang Li et al., "Improved SAPO-34 Membranes for CO2 / CH4 Separation", Adv. Mater. 2006, 18, 2601-2603 Halil Kalipcilar et al., "Synthesis and Separation Performance of SSZ-13 Zeolite Membranes on Tubular Supports", Chem. Mater. 2002, 14, 3458-3464

However, although DDR (Patent Document 1) has good separation performance, carbon dioxide has a low permeance (also referred to as "permeance") because the zeolite structure is two-dimensional. In addition, SAP is a CHA-type aluminophosphate that has a three-dimensional structure.
O-34 (Non-Patent Document 1) has good separation performance and permeence, but its performance in the presence of water deteriorates.

Further, in a chemical plant, the mixed gas often contains water, and the performance may deteriorate in the coexistence of water, which may not be practical. The CHA-type aluminosilicate SSZ-13 (Non-Patent Document 2), which is also a SUS support membrane, has non-zeolite pores (non-zeolite pores) in the zeolite membrane.
The separability was insufficient due to the coexistence of defects), and the permeence of carbon dioxide was also insufficient. As described above, a separation membrane for a gas mixture that can withstand practical use has not been known.

An object of the present invention is to provide a zeolite membrane composite having excellent water resistance and excellent separation of a gas mixture, which solves the problems of the prior art.

As a result of diligent studies to solve the above problems, the present inventors have obtained that when a zeolite membrane is formed on a porous support by hydrothermal synthesis, a reaction mixture having a specific composition is used on the support. We have found that the crystal orientation of the zeolite to be crystallized is improved, and that a dense zeolite membrane that achieves both a practically sufficient treatment amount and separation membrane performance is formed in the separation of a mixture of an organic compound and water.
Proposed earlier (Pamphlet No. 2010/098473, Japanese Patent Application Laid-Open No. 2011-12)
1040, 2011-121045, 2011-121854). As a result of further studies, the present inventors have found that by incorporating a certain metal into these zeolite membrane composites, the separation performance of the gas mixture is excellent and it can be a membrane separation means having a large processing amount. , The present invention has been reached.

That is, the gist of the present invention lies in the following (1) to (5).
(1) A method for producing a porous support-zeolite film composite having a zeolite film containing a divalent or higher valent metal excluding Al on an inorganic porous support, wherein the zeolite film is placed on the inorganic porous support. Is formed, and the zeolite membrane is impregnated with at least one metal selected from the group consisting of divalent or higher valent metals excluding Al, and then fired at a temperature of 500 ° C. or lower.
A method for producing a metal-containing zeolite membrane composite.
(2) The metal is prepared by immersing a zeolite membrane (membrane composite) formed on an inorganic porous support in a solution containing a metal element source compound, and using a solution containing a metal element source compound as a film composite. The method for producing a metal-containing zeolite membrane composite according to (1), which comprises spraying or dropping a solution containing a metal element source compound onto the membrane composite.
(3) The metal-containing according to (1) or (2), wherein the zeolite membrane (membrane composite) formed on the inorganic porous support is immersed in a solution containing a metal element source compound at 0 to 180 ° C. A method for producing a zeolite membrane composite.
(4) The concentration of the metal element source compound in the solution containing the metal element source compound is 0.01 to 5.
The method for producing a metal-containing zeolite membrane composite according to any one of (1) to (3), which is characterized by being molar / L.
(5) The zeolite membrane is formed by crystallizing zeolite on an inorganic porous support by hydrothermal synthesis using an aqueous reaction mixture containing an organic template (1) to (4).
The method for producing a metal-containing zeolite membrane composite according to any one of the above.

According to the present invention, it has excellent chemical resistance, heat stability, oxidation resistance, pressure resistance, a large amount of gas permeation, a high separation coefficient, high moist heat stability, and excellent separation of gas mixtures. A zeolite membrane composite can be provided. Further, by using the zeolite membrane composite of the present invention as a means for separating a gas mixture, it is possible to carry out gas separation with high performance with small-scale equipment, energy saving and low cost.

Further, according to the present invention, a highly permeable gas is permeated from the gas mixture, and the low permeable gas is concentrated to separate the highly permeable gas out of the system and release the low permeable gas. By concentrating and recovering, the target gas can be separated from the gas mixture with high purity.

It is a schematic diagram of the apparatus used for the permeation test of a single component gas. It is a schematic diagram of the apparatus used for gas separation. It is a schematic diagram of the apparatus used for a vapor permeation method. It is an XRD pattern of the CHA type zeolite membrane produced in Preparation Example 1. It is an XRD pattern of powdered CHA type zeolite. It is an XRD pattern of the CHA type zeolite membrane produced in Preparation Example 2. It is an XRD pattern of the CHA type zeolite membrane produced in Preparation Example 3.

Hereinafter, embodiments of the present invention will be described in more detail, but the description of the constituent requirements described below is an example of embodiments of the present invention, and the present invention is not limited to these contents. It can be modified in various ways within the scope of the gist. In addition, in this specification,
"Zeolite film composite in which a zeolite membrane is formed on an inorganic porous support" is referred to as "inorganic porous support-zeolite film composite" and "inorganic porous support-zeolite film composite".
"Zeolite membrane composite" or "membrane composite", "inorganic porous support" as "porous support" or "support", and "CHA-type aluminosilicate zeolite" as "CHA-type zeolite" May be abbreviated.

<Porous support-zeolite membrane composite>
The zeolite membrane composite of the present invention is a zeolite membrane composite used for permeating and separating a highly permeable component from a gas mixture composed of a plurality of components, and is composed of a divalent or higher valent metal excluding Al. It is characterized in that a zeolite membrane containing a CHA-type aluminosilicate zeolite containing at least one metal selected from the group is formed on an inorganic porous support.

In the present invention, as described above, the zeolite membrane composite is used as a membrane separation means for permeating and separating a highly permeable component from a gas mixture composed of a plurality of components.
Matters concerning the method of separating or concentrating a gas mixture, such as gas components, separation method, and separation performance,
The details of the zeolite membrane composite will be described later.

(Zeolite membrane)
In the present invention, the components constituting the zeolite membrane may contain, if necessary, an inorganic binder such as silica or alumina, an organic substance such as a polymer, or a silylating agent that modifies the surface of the zeolite, in addition to the zeolite.
The zeolite membrane may contain a part of an amorphous component or the like, but is preferably a zeolite membrane substantially composed of zeolite only.

The thickness of the zeolite membrane is not particularly limited, but is usually 0.1 μm or more, preferably 0.6 μm or more.
It is m or more, more preferably 1.0 μm or more. The range is usually 100 μm or less, preferably 60 μm or less, and more preferably 20 μm or less. If the film thickness is too large, the permeation amount tends to decrease, and if it is too small, the selectivity tends to decrease or the film strength tends to decrease.

The particle size of the zeolite forming the zeolite membrane is not particularly limited, but if it is too small, the grain boundaries tend to be large and the permeation selectivity tends to be lowered. 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. Further, it is more preferable that the particle size of the zeolite is the same as the thickness of the membrane. When the particle size of zeolite is the same as the thickness of the membrane, the grain boundary of zeolite is the smallest. The zeolite membrane obtained by hydrothermal synthesis, which will be described later, is preferable because the particle size of the zeolite and the thickness of the membrane may be the same.

The shape of the zeolite membrane (shape when formed into a membrane composite) is not particularly limited, and any shape such as tubular, hollow filament, monolith type, and honeycomb type can be adopted. The size is also not particularly limited. For example, in the case of a tubular shape, the length is usually 2 cm or more and 200 cm or less, and the inner diameter is 0.05 cm or more 2
Practical and preferable are cm or less and a thickness of 0.5 mm or more and 4 mm or less.

In the present invention, the zeolite membrane contains at least one metal selected from the group consisting of divalent or higher valent metals excluding Al. Examples of divalent or higher valent metals include Mg, Fe, and Ga.
, La, Cr, Zr, Sn, Ti and the like. Among these, Mg, Fe, La, C
r and Zr are preferable. As described above, these metal elements contained in the zeolite membrane may be one kind or a plurality of kinds by any combination.

It is considered that these metal elements are contained in the zeolite as ion exchange or oxide, or are replaced with a part of the skeleton of the zeolite.

The content of this metal element is determined by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-).
It can be measured by EDX), inductively coupled plasma (ICP) elemental analysis, X-ray photoelectron spectroscopy (XPS), and the like. In SEM-EDX, it is desirable to prepare a calibration curve for a sample whose metal element content value has been obtained by chemical analysis and quantify it. In ICP, the zeolite membrane portion can be dissolved with hydrofluoric acid or the like for measurement. XPS can measure the metal content of the film surface.

By containing these metal elements, when the metal element is present in the pores, it is considered that the effective pore size of the zeolite membrane changes according to the position of the metal element and the size of the metal atom. As the content of the metal element increases, the change in pore size also increases, and the suitable value of this pore size is determined by the molecular size of the component to be separated. Therefore, the suitable content of the metal element differs depending on the components to be separated. Even if a small amount of metal element is contained, the separation performance will be affected not a little depending on the amount, but if the target component separation performance can be achieved with a small amount, the amount of metal element is very large. It may be less. In addition, when it is necessary to significantly reduce the pore size in order to achieve the target separation performance, such as when all the component molecules to be separated are very small in size, it tends to be better to have a large metal element content. .. However, if the metal element content is too large, the pores tend to be clogged and gas permeation tends to be difficult to occur.

Further, a metal element having a low ionization tendency can become an oxide and exist outside the pores. When it exists outside the pores, if the location is a membrane defect, it acts to fill the membrane defect, which is considered to lead to improvement in separation performance. When there are many defects in the film, it is preferable that the content of the metal element is large, and in the case of a film having few defects, the content may be small. If there are too many metal elements outside the pores, the pore inlets may be blocked and the permeability may decrease.

Alternatively, when a metal element is incorporated into the zeolite skeleton, the pore diameter is slightly affected by the atomic diameter of the metal element species. When a metal element having a large atomic diameter is incorporated, the pore diameter tends to be large, and when a metal element having a small atomic diameter is incorporated, the pore diameter tends to be small. Even in this case, since a suitable pore size exists depending on the molecular size of the component to be separated, it is desirable to incorporate an amount of metal into the skeleton so as to have a suitable size.

Furthermore, regardless of the state in which the metal element is present, the component molecules that separate from the metal element may interact with each other. For example, if the inside of the zeolite pores becomes a highly polar field due to the presence of a metal element, polar molecules such as water vapor are likely to be adsorbed, and the permeation amount tends to be high. When each molecule interacts with a metal element in this way, the amount of permeation may be affected because the adsorptivity to the zeolite membrane is different. If the amount of metal element is too small, the adsorptive capacity cannot be sufficiently enhanced, and if it is too large, or if the amount of metal element is too high depending on the combination of the metal element and the component molecule, the molecule stays in the pores and does not penetrate the membrane. There is.

For the above reasons, the content of suitable metal elements varies depending on the components to be separated and the number of defects in the zeolite membrane. Therefore, the content of the metal element is not particularly limited, but A with respect to Al
The molar ratio of divalent or higher metals excluding l (divalent or higher metal / Al molar ratio) is usually 0.0002.
The above is preferably 0.0004 or more, more preferably 0.001 or more, still more preferably 0.003 or more, still more preferably 0.006 or more, still more preferably 0.01 or more. The upper limit is usually 20 or less, preferably 15 or less, more preferably 10 or less, still more preferably 5 or less, still more preferably 1 or less.

When the surface composition measured by XPS is used as a reference, the suitable value tends to differ from the overall composition due to the uneven distribution of Al and metal elements. Metal / Al molar ratio of divalent or higher, usually 0.00
It is 03 or more, preferably 0.0006 or more, more preferably 0.002 or more, still more preferably 0.005 or more, still more preferably 0.009 or more, still more preferably 0.02 or more. The upper limit is usually 30 or less, preferably 23 or less, more preferably 15 or less, still more preferably 8 or less, and more preferably 2 or less.

The "divalent or higher metal / Al molar ratio" is the molar ratio of the total amount of divalent or higher metals excluding Al to Al.

(Zeolite)
In the present invention, the zeolite constituting the zeolite membrane is a CHA type aluminosilicate. The almino silicate is mainly composed of oxides of Si and Al, and may contain other elements as long as the effects of the present invention are not impaired.

The effective pore size and polarity of zeolite can also be controlled by acid treatment, silylation and the like. It is also possible to improve the separation performance by controlling the effective pore size.

By performing the acid treatment, depending on the conditions, at least a part of the metal usually introduced into the skeleton tends to be desorbed from the skeleton, and the metal ions existing in the pores tend to be exchanged for H +. When the metal is detached from the skeleton, the decrease in the amount of metal has the effect of lowering the polarity.
In addition, the pore size may change depending on the atomic diameter of the desorbed metal. Similarly, when the metal ions in the pores are exchanged for H +, the pore size and the polarity in the pores can be changed depending on the atomic diameter and the polarity of the exchanged metal.

Cyrilization can also reduce the effective pore size of zeolite. By silylating the terminal silanol on the outer surface and further laminating the silylated layer, the effective pore diameter of the pores facing the outer surface of the zeolite is generally reduced.

In the present invention, the SiO ₂ / Al ₂ O ₃ molar ratio of the aluminosilicate is not particularly limited, but is usually 6 or more, preferably 10 or more, more preferably 20 or more, still more preferably 30 or more, still more preferably 32 or more. It is more preferably 35 or more, and particularly preferably 40 or more. The upper limit is usually the amount of Al as an impurity, and the SiO ₂ / Al ₂ O ₃ molar ratio is usually 500 or less, preferably 100 or less, more preferably 90 or less, still more preferably 80 or less, still more preferably 65. Below, it is particularly preferably 48 or less. SiO ₂ / Al
In less than ₂ O ₃ molar ratio of the lower limit may decrease the density of the zeolite membrane, also tends to durability is lowered.
The SiO ₂ / Al ₂ O ₃ molar ratio can be adjusted by the reaction conditions of hydrothermal synthesis described later.

The SiO ₂ / Al ₂ O ₃ molar ratio is a numerical value obtained by a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX). The acceleration voltage of X-rays is usually measured at 10 kV in order to obtain information on only a few microns of film.

(CHA type zeolite)
In the present invention, the CHA-type zeolite is referred to as the International Zeolite Association (IZA).
Indicates a CHA structure with a code that defines the structure of zeolite defined by. It is a zeolite having a crystal structure equivalent to that of naturally occurring chabacite. CHA type zeolite is 0.3
It has a structure characterized by having three-dimensional pores composed of an oxygen 8-membered ring having a diameter of 8 × 0.38 nm, and the structure is characterized by X-ray diffraction data.

The framework density (T / nm3) of CHA-type zeolite is 14.5. Also, S
The iO ₂ / Al ₂ O ₃ molar ratio is the same as above.
Here, the framework density (T / nm ^{3 ) is nm 3} (1000 Å 3) of zeolite.
) Means the number of elements other than oxygen (T element) constituting the skeleton, and this value is determined by the structure of zeolite. The relationship between framework density and zeolite structure is shown in ATLAS OF ZEOLITE FRAMEWORK TYPES Fifth Revised Edition 2001 ELSEVIER.

(Inorganic porous support)
The inorganic porous support may be any porous inorganic substance having chemical stability such that zeolite can be crystallized into a film on the surface thereof. Specifically, for example, ceramic sintered bodies such as silica, α-alumina, γ-alumina, mullite, zirconia, titania, itria, silicon nitride, silicon carbide, sintered metals such as iron, bronze, and stainless steel, and glass. , Carbon molded body and the like.

Among the inorganic porous supports, the ceramic sintered body has an effect of enhancing the adhesion at the interface by converting a part of the ceramic sintered body into zeolite during the synthesis of the zeolite membrane.
Furthermore, in the inorganic porous support containing at least one of alumina, silica, and mullite, the support is easily partially zeolitezized, so that the bond between the support and the zeolite is strengthened, resulting in a dense and separation performance. It is more preferable because a tall film is easily formed.

The shape of the support is not particularly limited as long as it can effectively separate the gas mixture, and specifically, for example, there are a large number of flat plate-shaped, tubular, cylindrical, cylindrical, or prismatic holes. Examples include honeycomb-shaped ones and monoliths.
In the present invention, a zeolite film is formed on the surface of an inorganic porous support or the like, and zeolite is preferably crystallized into a film.

The average pore diameter of the support is not particularly limited, but one having a controlled pore diameter is preferable, and usually 0.02 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm.
It is usually 20 μm or less, preferably 10 μm or less, and more preferably 5 μm or less. If the 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 tends to be insufficient, or it tends to be difficult to form a dense zeolite membrane.

The surface of the support is preferably smooth, and the surface may be sanded or the like if necessary. The surface of the support means the surface portion of the support on which the zeolite membrane is formed.
As long as it is a surface, it may be any surface of each shape, or it may be a plurality of surfaces. For example, in the case of a cylindrical tube support, it may be either an outer surface or an inner surface, and in some cases both outer and inner surfaces.

Further, the porosity of the support is not particularly limited and does not need to be controlled in particular, but the porosity is determined.
Usually, it is preferably 20% or more and 60% or less. The porosity affects the permeation flow rate when separating a gas or liquid, and if it is less than the lower limit, it tends to hinder the diffusion of the permeated material, and if it exceeds the upper limit, the strength of the support tends to decrease.

(Zeolite membrane complex)
A zeolite membrane composite is one in which zeolite is adhered to the surface of a support in the form of a film, and in some cases, a part of zeolite is adhered to the inside of the support. preferable.

As the zeolite membrane composite, for example, one in which zeolite is crystallized into a film by hydrothermal synthesis on the surface of a support or the like is preferable.

The position of the zeolite membrane on the support is not particularly limited, and when a tubular support is used, the zeolite membrane may be attached to the outer surface or the inner surface, and depending on the system to be applied, it may be attached to both sides. May be good. Further, it may be laminated on the surface of the support, or it may be crystallized so as to fill the pores of the surface layer of the support. In this case, it is important that there are no cracks or continuous micropores inside the crystallized film layer, and forming a so-called dense film improves the separability.

In the zeolite membrane composite of the present invention, in the X-ray diffraction pattern obtained by irradiating the membrane surface with X-rays, the intensity of the peak near 2θ = 17.9 ° is the intensity of the peak near 2θ = 20.8 °. It is preferably 0.5 times or more of.

Here, the peak intensity refers to the measured value minus the background value. (
Peak intensity ratio expressed by 2θ = peak intensity near 17.9 °) / (peak intensity near 2θ = 20.8 °) (hereinafter this may be referred to as “peak intensity ratio A”). Speaking of which, it is preferably 0.5 or more, more preferably 0.8 or more. The upper limit is not particularly limited, but is usually 1000 or less.

Further, in the present invention, the zeolite membrane composite has 2θ = 9 in the pattern of X-ray diffraction.
.. It is preferable that the intensity of the peak near 6 ° is 2.0 times or more the intensity of the peak near 2θ = 20.8 °.

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”). Speaking of which
It is preferably 2.0 or more, more preferably 2.5 or more, more preferably 3 or more, still more preferably 4 or more, still more preferably 6 or more, still more preferably 8 or more, and particularly preferably 10 or more.
That is all. The upper limit is not particularly limited, but is usually 1000 or less.

The X-ray diffraction pattern referred to here is Cu on the surface on the side where zeolite is mainly attached.
By irradiating X-rays with Kα as the radiation source, the scanning axis is obtained as θ / 2θ. The shape of the sample to be measured may be any shape as long as the surface of the membrane composite on the side to which the zeolite is mainly attached can be irradiated with X-rays. It is preferably as it is, or cut to an appropriate size constrained by the device.

When the surface of the zeolite membrane composite is a curved surface, the X-ray diffraction pattern referred to here may be measured by fixing the irradiation width using an automatic variable slit. The X-ray diffraction pattern when the automatically variable slit is used refers to a pattern in which variable → fixed slit correction is performed.

Here, the peak near 2θ = 17.9 ° is 17.9 ° among the peaks not derived from the base material.
Refers to the largest peak existing in the range of ± 0.6 °.

The peak near 2θ = 20.8 ° is 20.8 ° ± 0.6 among the peaks not derived from the base material.
Refers to the largest peak in the ° range.

The peak near 2θ = 9.6 ° refers to the largest peak existing in the range of 9.6 ° ± 0.6 ° among the peaks not derived from the base material.

The peak near 2θ = 9.6 ° in the X-ray diffraction pattern is COLLECTION OF SIMULATED XRD POWD
According to ER PATTERNS FOR ZEOLITE Third Revised Edition 1996 ELSEVIER rhombohedral
Space group with setting

When (No. 166) is set, it is a peak derived from the plane whose exponent is (1,0,0) in the CHA structure.

In the X-ray diffraction pattern, the peak near 2θ = 17.9 ° is COLLECTION OF SIMULATED.
According to XRD POWDER PATTERNS FOR ZEOLITE Third Revised Edition 1996 ELSEVIER rhomb
Space group with ohedral setting

When (No. 166) is set, it is a peak derived from the plane whose exponent is (1,1,1) in the CHA structure.

The peak near 2θ = 20.8 ° in the X-ray diffraction pattern is COLLECTION OF SIMULATED XRD PO
According to WDER PATTERNS FOR ZEOLITE Third Revised Edition 1996 ELSEVIER rhombohedra
l setting the space group

When (No. 166) is set, it is a peak derived from the plane whose exponent is (2,0, -1) in the CHA structure.

The typical ratio (peak intensity ratio B) of the peak intensity derived from the (1,0,0) plane to the peak intensity derived from the (2,0, -1) plane in the zeolite membrane of CHA type aluminosilicate is According to Non-Patent Document 2, it is less than 2.

Therefore, if this ratio is 2.0 or more, for example, the CHA structure is rhombohedr.
It is considered that this means that the zeolite crystals are oriented and grown so that the (1,0,0) plane when the al setting is set is oriented so as to be almost parallel to the surface of the membrane composite. The 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.

According to Non-Patent Document 2, the typical ratio (peak intensity ratio A) of the peak intensity derived from the (1,1,1) plane to the peak intensity derived from the (2,0, -1) plane is 0. Less than .5.

Therefore, if this ratio is 0.5 or more, for example, the CHA structure is rhombohedr.
It is considered that this means that the zeolite crystals are oriented and grown so that the (1,1,1) plane when the al setting is set is oriented so as to be almost parallel to the surface of the membrane composite. The 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, when either of the peak intensity ratios A and B is a value in the above-mentioned specific range, the zeolite crystals are oriented and grown to form a dense film having high separation performance. Is shown.

Here, the peak intensity ratios A and B indicate that the larger the value is, the stronger the degree of orientation is, and generally, the stronger the degree of orientation is, the denser the film is formed. Generally, the stronger the orientation, the higher the separation performance tends to be. However, the optimum degree of orientation that improves the separation performance differs depending on the mixture to be separated. Therefore, the optimum degree of orientation depends on the mixture to be separated. It is desirable to select and use the membrane complex.

As described below, a dense zeolite membrane in which CHA-type zeolite crystals are oriented and grown is contained in an aqueous reaction mixture using, for example, a specific organic template when the zeolite membrane is formed by a hydrothermal synthesis method. It can be achieved by coexisting K + ions.

<Manufacturing method of zeolite membrane composite>
In the present invention, the method for producing a zeolite membrane is not particularly limited as long as it is a method capable of forming the above-mentioned specific zeolite membrane, and for example, (1) a method for crystallizing CHA-type zeolite in a film shape on a support. , (2) A method of fixing CHA-type zeolite to a support with an inorganic binder or an organic binder, (3) a method of fixing a polymer in which CHA-type zeolite is dispersed, (4) A method of fixing a CHA-type zeolite slurry to a support The zeolite membrane composite produced by impregnating the zeolite with the zeolite and, in some cases, sucking the zeolite to the support, contains a specific metal element by post-treatment, or hydrothermally synthesizes the zeolite. Any method such as a method in which a specific metal element is contained in a reaction mixture for hydrothermal synthesis (hereinafter, this may be referred to as an "aqueous reaction mixture") can be used.

Among these, a method in which zeolite is crystallized into a film on an inorganic porous support and a metal element is contained by post-treatment is particularly preferable.
The crystallization method is not particularly limited, but there is a method in which the support is placed in a reaction mixture for hydrothermal synthesis used for zeolite production and the zeolite is crystallized on the surface of the support by direct hydrothermal synthesis. preferable.

Specifically, for example, the aqueous reaction mixture whose composition has been adjusted and homogenized may be placed in a heat-resistant and pressure-resistant container such as an autoclave in which a support is loosely fixed inside, sealed, and heated for a certain period of time.

The aqueous reaction mixture preferably contains a Si element source, an Al element source, an alkali source, and water, and if necessary, contains an organic template.

As the Si element source used in the aqueous reaction mixture, for example, amorphous silica, colloidal silica, silica gel, sodium silicate, amorphous aluminum silicate gel, tetraethoxysilane (TEOS), trimethylethoxysilane and the like can be used.

As the Al element source, for example, sodium aluminate, aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum oxide, amorphous aluminosilicate gel and the like can be used.

The type of alkali used as the alkali source is not particularly limited, and alkali metal hydroxides, alkaline earth metal hydroxides, and hydroxide ions of counter anions of organic templates can also be used.

The metal species of the metal hydroxide are usually Na, K, Li, Rb, Cs, Ca, Mg, Sr, Ba,
It is preferably Na, K, and more preferably K. Further, two or more kinds of metal hydroxides may be used in combination, and specifically, Na and K or Li and K are preferably used in combination.

Specifically, examples of the alkali source include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, and cesium hydroxide; calcium hydroxide, magnesium hydroxide, and strontium hydroxide. , Alkaline earth metal hydroxides such as barium hydroxide and the like can be used.

As the alkali source used in the aqueous reaction mixture, the hydroxide ion of the counter anion of the organic template described below can be used. While the organic template also serves as an alkali source, it also serves as a structural defining material even when it does not serve as an alkali source.

In the crystallization of zeolite, an organic template (structure-determining agent) can be used if necessary, but those synthesized using the organic template are preferable. By synthesizing using an organic template, the ratio of silicon atoms to aluminum atoms of the crystallized zeolite is increased, and the crystallinity is improved.

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

Specifically, for example, cations derived from alicyclic amines such as cations derived from 1-adamantanamine, cations derived from 3-quinacridinal, and cations derived from 3-exo-aminonorbornene are listed. Is done. Of these, cations derived from 1-adamantanamine are more preferred. When a cation derived from 1-adamantanamine is used as an organic template, CHA-type zeolite capable of forming a dense film crystallizes.

Of the cations derived from 1-adamantanamine, N, N, N-trialkyl-1
-Adamantane ammonium cations are more preferred. N, N, N-trialkyl-1-
The three alkyl groups of the adamantane ammonium cation are usually independent alkyl groups, preferably lower alkyl groups, more preferably methyl groups. The most preferred compounds among them are N, N, N-trimethyl-1-adamantanammonium cations.

Such cations are accompanied by anions that do not harm the formation of CHA-type zeolites.
Representatives of such anions include halogen ions such as Cl-, Br-, I-, hydroxide ions, acetates, sulfates, and carboxylates. Of these, hydroxide ions are particularly preferably used.

As other organic templates, N, N, N-trialkylbenzylammonium cations can also be used. In this case as well, the alkyl groups are independent alkyl groups, preferably lower alkyl groups, and more preferably methyl groups. Among them, the most preferable compound is N, N, N-trimethylbenzylammonium cation. Also,
The anion accompanied by this cation is the same as above.

The ratio of the Si element source to the Al element source in the aqueous reaction mixture is usually _{expressed as the molar ratio of oxides of each element, that is, the SiO 2} / Al ₂ O ₃ molar ratio.

The SiO ₂ / Al ₂ O ₃ ratio is not particularly limited as long as a zeolite having the above-mentioned SiO ₂ / Al ₂ O ₃ ratio can be formed, but is usually 5 or more, preferably 20 or more, and more preferably 30. Above, more preferably 40 or more, particularly preferably 50 or more. The upper limit is usually 500 or less, preferably 200 or less, more preferably 150 or less, still more preferably 100 or less. When the SiO ₂ / Al ₂ O ₃ ratio is in this range, CHA-type aluminosilicate zeolite capable of forming a dense film can be crystallized.

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 ratio) is usually 0.005 or higher, preferably at least 0.01, more preferably 0. It is 02 or more, usually 1 or less, preferably 0.4 or less, and more preferably 0.2 or less. When it is in this range, a dense zeolite membrane can be formed, and the formed zeolite has strong acid resistance and Al is difficult to be desorbed. Further, under these conditions, a particularly dense and acid-resistant CHA-type aluminosilicate zeolite can be formed.

The ratio of the Si element source to the alkali source is M ₂ O / SiO ₂ (where M indicates an alkali metal) molar ratio, usually 0.02 or more, preferably 0.04 or more, more preferably 0. It is 05 or more, usually 0.5 or less, preferably 0.4 or less, and more preferably 0.3 or less.

When forming a zeolite membrane of CHA type aluminosilicate, potassium (in alkali metal)
The case where K) is contained is preferable in that a more dense and highly crystalline film is formed. In that case, the molar ratio of K to all alkali metals and / or alkaline earth metals including K is usually 0.01 or more, preferably 0.1 or more, more preferably 0.3 or more, and the upper limit is Is usually 1 or less.

The addition of K into the aqueous reaction mixture constructed in a preferred embodiment of the present invention is as described above.
Space group with rhombohedral setting

When (No. 166) is set, the peak intensity near 2θ = 9.6 °, which is the peak derived from the plane having an exponent of (1,0,0) in the CHA structure, and the plane of (2,0, -1). The ratio of peak intensities around 2θ = 20.8 °, which is the peak derived from (peak intensity ratio B), or (1,1,1
The peak intensity near 2θ = 17.9 °, which is the peak derived from the surface of 1), and (2,0, -1)
Ratio of peak intensities around 2θ = 20.8 °, which is the peak derived from the surface of
Tends to increase.

The ratio of Si element source to water is the molar ratio of water to _{SiO 2 (H 2} O / SiO ₂ molar ratio).
It is usually 10 or more, preferably 30 or more, more preferably 40 or more, particularly preferably 50 or more, usually 1000 or less, preferably 500 or less, more preferably 200 or less, and particularly preferably 150 or less.

Dense zeolite membranes can form when the molar ratio of substances in the aqueous reaction mixture is in these ranges. The amount of water is particularly important in the formation of a dense zeolite membrane, and a dense membrane tends to be formed under the condition that the amount of water is larger than that of the general condition of the powder synthesis method.

Generally, the amount of water used to synthesize the powdered CHA-type aluminosilicate zeolite is H _2.
The O / SiO ₂ molar ratio is about 15 to 50. CHA on the surface of the support, etc., by setting the condition that the H ₂ O / SiO ₂ molar ratio is high (50 or more and 1000 or less), that is, the amount of water is large.
It is possible to obtain a zeolite membrane composite having high separation performance in which the zeolite of the type aluminosilicate is crystallized into a dense membrane.

By including the metal element source (ion source) in the aqueous reaction mixture during hydrothermal synthesis, the metal can be contained in the zeolite membrane at the same time as the zeolite membrane is formed. This makes it possible to obtain a zeolite membrane in which the above metal elements are highly dispersed.

Examples of the metal element source compound (metal ion source compound) that can be used include nitrates, sulfates, acetates, phosphates, hydroxides, chlorides, and complexes of the metal elements. Of these, nitrates, sulfates and complexes are preferred. In the present specification, the metal element source compound and the metal ion source compound are synonymous.

The content of the metal element source compound in the aqueous reaction mixture is usually 0.00 in molar ratio to Si.
1 or more, preferably 0.005 or more, more preferably 0.01 or more, and usually 0.
It is 3 or less, preferably 0.2 or less, and more preferably 0.1 or less.

Further, in hydrothermal synthesis, the seed crystal does not necessarily have to be present in the reaction system, but the addition of the seed crystal can promote the crystallization of zeolite 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 as in the synthesis of powdered zeolite, a method of adhering the seed crystal on the support, or the like is used. Can be done.
When producing a zeolite membrane composite, it is preferable to attach a seed crystal on the support. By adhering seed crystals on the support in advance, it becomes easy to form a dense zeolite membrane with good separation performance.

The seed crystal to be used may be of any type as long as it is a zeolite that promotes crystallization, but in order to crystallize efficiently, it is preferable that the seed crystal has the same crystal type as the zeolite membrane to be formed.
When forming a zeolite membrane of CHA-type aluminosilicate, it is preferable to use a seed crystal of CHA-type zeolite.

It is desirable that the grain size of the seed crystal is small, and it may be pulverized and used if necessary. The particle size is usually 0.5 nm or more, preferably 1 nm or more, more preferably 2 nm or more, and usually 5 μm or less, preferably 3 μm or less, more preferably 2 μm or less.

The method of adhering the seed crystal on the support is not particularly limited, and 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 liquid to adhere the seed crystal to the surface. A method of applying a slurry of seed crystals mixed with a solvent such as water onto a support can be used. The dip method is desirable in order to control the amount of seed crystals attached and to produce a membrane composite with good reproducibility.

The solvent for dispersing the seed crystals is not particularly limited, but water and an alkaline aqueous solution are particularly preferable. The type of the alkaline aqueous solution is not particularly limited, but a sodium hydroxide aqueous solution and a potassium hydroxide aqueous solution are preferable. Moreover, these alkaline species may be mixed. The alkali concentration is not particularly limited, and is usually 0.0001 mol% or more, preferably 0.0002 mol% or more, more preferably 0.001 mol% or more, still more preferably 0.002 mol% or more. Further, it is usually 1 mol% or less, preferably 0.8 mol% or less, more preferably 0.
.. It is 5 mol% or less, more preferably 0.2 mol% or less.

If the amount of seed crystals to be dispersed is too small, the amount of seed crystals adhering to the support will be small.
During hydrothermal synthesis, there may be a part on the surface of the support where zeolite is not formed, resulting in a defective film. If the amount of seed crystals in the dispersion is too large, the amount of seed crystals adhering to the support by the dip method becomes almost constant, so that the seed crystals are wasted, which is disadvantageous in terms of cost.

It is desirable to attach seed crystals to the support by a dip method or a slurry coating, and to form a zeolite membrane after drying.

The amount of seed crystals to be adhered to the support in advance is not particularly limited, and ^{the amount per 1 m 2 of} the base material is usually 0.01 g or more, preferably 0.05 g or more, and more preferably 0.1 g or more. , Usually 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 seed crystals is less than the lower limit, it becomes difficult to form crystals, and the growth of the film tends to be insufficient or the growth of the film tends to be non-uniform. In addition, when the amount of seed crystals exceeds the upper limit, the unevenness of the surface is increased by the seed crystals, or the seed crystals fallen from the surface of the support facilitate the growth of spontaneous nuclei and inhibit the film growth on the support. It may be done. In either case, it tends to be difficult to form a dense zeolite membrane.

When the zeolite membrane is formed on the support by hydrothermal synthesis, the method of immobilizing the support is not particularly limited, and any form such as vertical placement or horizontal placement can be taken. In this case, the zeolite membrane may be formed by a static 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, still more preferably 180 ° C. or higher. It is as follows. If the reaction temperature is too low, the zeolite may be difficult to crystallize. Further, if the reaction temperature is too high, a zeolite of a type different from that of the zeolite in the present invention may be easily produced.

The heating (reaction) time is not particularly limited, but is usually 1 hour or more, preferably 5 hours or more, more preferably 10 hours or more, usually 10 days or less, preferably 5 days or less, more preferably 3 days or less, and further. It is preferably 2 days or less. If the reaction time is too short, it may be difficult for the zeolite to crystallize. If the reaction time is too long, a zeolite of a type different from that of the zeolite in the present invention may be easily produced.

The pressure at the time of forming the zeolite membrane is not particularly limited, and the aqueous reaction mixture placed in the closed container is used.
The self-sustaining pressure generated when heated to this temperature range is sufficient. Further, if necessary, an inert gas such as nitrogen may be added.

The zeolite membrane composite obtained by hydrothermal synthesis is washed with water, heat-treated, and dried. Here, the heat treatment means that heat is applied to dry the zeolite membrane composite or the template is fired when 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, and usually 200 ° C. or lower, preferably 150 ° C. or lower for the purpose of drying. When the purpose is to bake the template, it is usually 350 ° C. or higher, preferably 400 ° C. or higher, more preferably 430 ° C. or higher, still more preferably 450 ° C. or higher, usually 900 ° C. or lower, preferably 850 ° C. or lower, further preferably Is 800 ° C. or lower, particularly preferably 750 ° C.
It is as follows.

The time of the heat treatment is not particularly limited as long as the zeolite membrane is sufficiently dried or the template is fired, and is preferably 0.5 hours or more, more preferably 1 hour or more.
The upper limit is not particularly limited, and is usually 200 hours or less, preferably 150 hours or less, and more preferably 100 hours or less.

When hydrothermal synthesis was performed in the presence of an organic template, the resulting zeolite membrane composite was
After washing with water, it is appropriate to remove the organic template by, for example, heat treatment or extraction, preferably heat treatment, that is, firing.

If the calcination temperature is too low, the proportion of organic templates remaining tends to increase, and the pores of zeolite are small, which may reduce the amount of gas permeated during separation and concentration. If the firing 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 zeolite membrane may lose its denseness and the separation performance may be lowered. ..

The firing time varies depending on the heating rate and the temperature decreasing rate, but is not particularly limited as long as the organic template is sufficiently removed, and is preferably 1 hour or more, more preferably 5 hours or more. The upper limit is not particularly limited, and is usually 200 hours or less, preferably 150 hours or less, more preferably 100 hours or less, and particularly preferably 24 hours or less. The firing may be carried out in an air atmosphere, but may be carried out in an atmosphere in which oxygen is added.

It is desirable that the rate of temperature rise during firing be as slow as possible in order to reduce the difference in the coefficient of thermal expansion between the support and the zeolite from causing cracks in the zeolite membrane. The heating 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.

In addition, the temperature lowering rate after firing also needs to be controlled in order to prevent cracks in the zeolite membrane. As with the rate of temperature rise, the slower the temperature, the more desirable. The temperature drop 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.

Next, the obtained zeolite membrane is post-treated to contain a metal as described above. The method of post-treatment is not particularly limited as long as the film complex can come into contact with a solution containing a metal element source compound (metal ion source compound), but for example, a film is applied to a solution containing a metal element source compound. Examples thereof include a method of immersing the complex, a method of spraying a solution containing a metal element source compound onto the membrane composite, and a method of dropping the complex.

Examples of the metal element source compound include nitrates, sulfates, acetates, phosphates, chlorides, metal complexes and the like of the metal elements, and nitrates, sulfates and chlorides are preferable.

One of these metal element source compounds may be used alone, or two or more thereof may be used in combination in any combination.

The concentration of the metal element source compound in the dipping, spraying, or dropping solution is usually 0.01 mol / L or more, preferably 0.03 mol / L or more, more preferably 0.05 mol / L or more, and usually. It is 5 mol / L or less, preferably 3 mol / L or less, and more preferably 1 mol / L or less.
If the concentration of the compound is too low, the effect of improving the separation performance is small, and if the concentration is too high, the pores are clogged and the amount of the component to be permeated tends to be small.

When the film composite is immersed in a solution containing a metal element source compound, the temperature is not particularly limited, but is usually 0 ° C. or higher, preferably 20 ° C. or higher, more preferably 50 ° C. or higher, and usually 2 ° C. or higher.
It is 00 ° C. or lower, preferably 190 ° C. or lower, and more preferably 180 ° C. or lower.

The pressure is not particularly limited, and it may be carried out in an open container under atmospheric pressure, or it may be carried out under the spontaneous pressure generated when the container is placed in a closed container and heated in this temperature range. In the case of a closed container, an inert gas such as nitrogen may be added as needed.

After soaking, it may be washed with water and then dried at a temperature of 30 ° C. to 120 ° C., or it may be dried without washing. If necessary, it may be fired after drying.

When a solution containing a metal element source compound is sprayed or dropped onto a membrane composite, the temperature is not particularly limited, but is usually 0 ° C. or higher, preferably 5 ° C. or higher, more preferably 10 ° C. or higher, and usually 100 ° C. or lower. It is preferably 90 ° C. or lower, more preferably 80 ° C. or lower.

The pressure is not particularly limited and is usually carried out under atmospheric pressure, but the inside of the zeolite membrane composite may be reduced in pressure.

Spraying or dropping can usually be performed until the amount of the solution containing the metal element source compound in the zeolite membrane exceeds the volume of the pores and the surface becomes wet. After the treatment, the temperature is usually 30 ° C to 120 ° C.
Dry at the temperature of. If necessary, it may be fired after drying.

The firing temperature after drying is usually 200 ° C. or higher, preferably 250 ° C. or higher, more preferably 300 ° C. or higher, and usually 550 ° C. or lower, preferably 525 ° C. or lower, more preferably 50 ° C. or higher.
It is 0 ° C. or lower.

The firing time is not particularly limited as long as the anion such as nitrate ion is partially or completely removed, 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, more preferably 1.
Within 00 hours.

It is desirable that the rate of temperature rise during firing be as slow as possible in order to reduce the difference in thermal expansion coefficient between the support and the zeolite from causing cracks in the zeolite membrane. The heating 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.

In addition, it is necessary to control the temperature lowering rate after firing in order to prevent cracks in the zeolite membrane. As with the rate of temperature rise, the slower the temperature, the more desirable. The temperature lowering rate is usually 5 ° C.
/ Min or less, preferably 2 ° C / min or less, more preferably 1 ° C / min or less, particularly preferably 0.
.. It is 5 ° C./min or less. Usually, it is 0.1 ° C./min or more in consideration of workability.

The amount of air permeation of the zeolite membrane composite after drying or firing is usually 1300 L / (m ² · h).
Below, preferably 900 L / (m ² · h) or less, more preferably 600 L / (m ² · h).
Below, more preferably 500 L / (m ² · h) or less, still more preferably 400 L / (m ^2).
H) or less, particularly preferably 250 L / (m ² · h) or less, most preferably 150 L
/ (M ² · h) or less. The lower limit of the permeation amount is not particularly limited, but is usually 0 L / (m ² · h).
) Or more, preferably 0.01L / ^(m 2 · h) or more, more preferably 0.1L / ^{(m 2} ·
h) or more, more preferably 1 L / (m ² · h) or more.

Here, the amount of air permeation is the amount of air permeation when the zeolite membrane composite is placed under atmospheric pressure and the inside of the zeolite membrane composite is connected to a vacuum line of 5 kPa, as described in detail in the section of Examples. [L / (m ² · h)].

The amount of air permeation is a numerical value that leads to the amount of gas permeation. If the amount of air permeation is large, the amount of gas component permeated is also large, and if the amount of air permeation is too large, the separation tends to be low. The zeolite membrane of the present invention has an appropriately large amount of air permeation and has sufficiently high separation performance, and has performance suitable for gas separation performance.

The zeolite membrane composite thus produced has excellent properties and can be suitably used as a membrane separation means for the gas mixture in the present invention.

<Method of separating or concentrating gas mixture>
(Separation of gas)
In the separation or concentration method of the present invention, a gas mixture composed of a plurality of components is brought into contact with the zeolite membrane composite, and a highly permeable component is permeated and separated from the gas mixture, or
It is characterized in that a component having low permeability is concentrated by permeating and separating a component having high permeability. One of the separation functions of the zeolite membrane in the present invention is separation as a molecular sieve, and it is possible to preferably separate gas molecules having a size equal to or larger than the effective pore diameter of the zeolite used and gas molecules having a size smaller than that. it can.

Therefore, the highly permeable gas component in the present invention is a gas component composed of gas molecules that easily pass through the pores of the zeolite crystal phase of CHA-type aluminosilicate, and has a molecular diameter of approximately 0.3.
A gas component composed of gas molecules smaller than about 8 nm is preferable.

Here, in the present invention, the gas mixture to be separated is not limited to a gas mixture at normal temperature and pressure, but also includes a liquid that is liquid at normal temperature and pressure and can become a gas mixture by vaporization. Is done. The method of using the vaporized gas mixture as the separation target is a separation or concentration method called a vapor permeation method (steam permeation method), which is one embodiment of the method of the present invention. This method is particularly suitable, for example, for separating or concentrating a mixture of an organic compound and water. In this case, since water is usually highly permeable to the zeolite membrane,
Water is separated from the mixture and the organic compounds are concentrated in the original mixture.

In the present invention, the gas mixture to be separated is not particularly limited as long as it can be a gas mixture that is a gas at normal temperature and pressure and a gas mixture by vaporization as described above.
Desirable gas mixtures for separation include, for example, carbon dioxide, hydrogen, oxygen, nitrogen, methane, ethane, ethylene, propane, propylene, normal butane, isobutane, etc.
Examples thereof include those containing at least one component selected from 1-butene, 2-butene, isobutene, sulfur hexafluoride, helium, carbon monoxide, nitric oxide, water and the like. Among the components of the gas mixture containing the gas, the component having a high permeence permeates through the zeolite membrane composite and is separated, and the component having a low permeence is concentrated on the supply gas side.

Further, as the gas mixture, a mixture containing at least two kinds of the above-mentioned components is more preferable. In this case, as the two types of components, a combination of a component having a high permeence and a component having a low permeence is preferable.

The gas separation conditions vary depending on the type and composition of the target gas component and the performance of the membrane, but the temperature is usually 0 to 300 ° C, preferably room temperature to 200 ° C, and more preferably room temperature to 150 ° C.

As long as the gas component to be separated has a high pressure, the pressure of the supply gas may be the same as it is, or the pressure may be appropriately reduced and adjusted to a desired pressure. When the gas component to be separated is lower than the pressure used for separation, the pressure can be increased by a compressor or the like before use.

The pressure of the supply gas is not particularly limited, but is usually higher than atmospheric pressure or atmospheric pressure, preferably 0.1 MPa or more, more preferably 0.11 MPa or more. The upper limit is usually 20 MPa or less, preferably 10 MPa or less, and more preferably 1 MPa or less.

The differential pressure between the gas component on the supply side and the gas component on the permeation side is not particularly limited, but is usually 20 MPa or less, preferably 10 MPa or less, more preferably 5 MPa or less, still more preferably 1 MPa or less.
It is as follows. Further, it is usually 0.001 MPa or more, preferably 0.01 MPa or more, and more preferably 0.02 MPa or more.

Here, the differential pressure means the difference between the partial pressure on the supply side and the partial pressure on the permeation side of the gas. Also, pressure [
Pa] refers to the absolute pressure unless otherwise specified.

The pressure on the permeation side is not particularly limited, but is usually 10 MPa or less, preferably 5 MPa or less.
It is more preferably 1 MPa or less, still more preferably 0.5 MPa or less. The lower limit is not particularly limited and may be 0 MPa or more. When it is set to 0 MPa, it is possible to separate the gas having high permeability in the gas having low permeability until the concentration becomes the lowest. If there is an application in which the permeation side gas is used with a high pressure, the permeation side pressure may be set high.

The flow velocity of the supply gas should be a certain flow velocity that can compensate for the decrease in the permeated gas, and in the supply gas, the concentration in the immediate vicinity of the film of the gas with low permeability should be the same as the concentration in the entire gas. , The flow rate may be such that the gas can be mixed. Specifically, although it depends on the pipe diameter of the separation unit and the separation performance of the membrane, for example, it is usually 0.5 mm / sec or more, preferably 1 mm / sec or more, and the upper limit is not particularly limited, but is usually 1 m / sec. It is sec or less, preferably 0.5 m / sec or less.

Sweep gas may be used in the separation or concentration method of the present invention. The method using a sweep gas is to flow a gas of a type different from the supply gas on the permeation side and recover the gas that has permeated the membrane.
The pressure of the sweep gas is usually atmospheric pressure, but is not particularly limited, and is preferably 20 MPa or less, more preferably 10 MPa or less, still more preferably 1 MPa or less, and the lower limit is preferably 0.09 MPa or more, more preferably 0. .1 MPa or more. In some cases,
It may be used with reduced pressure.

The flow velocity of the sweep gas is not particularly limited, but is usually ^10-7 mol / (m ² · s) or more 1
It is 04 mol / (m ² · s) or less.

The apparatus used for separating the gas mixture is not particularly limited, but it is usually preferable to use it as a module (separation membrane module). The separation membrane module for separating a gas mixture that is a gas at normal temperature and pressure may be, for example, an apparatus schematically shown in FIGS. 1 and 2, or "Gas Separation / Purification Technology" Co., Ltd. The membrane module illustrated on page 22 of the 2007 Toray Research Center may be used. Separation of the gas mixture in the apparatus of FIGS. 1 and 2 will be described in the section of Examples.

In addition, as described above, the vapor permeation method is a separation / concentration method in which a mixture of liquids is vaporized and then introduced into a separation membrane, so that it can be used in combination with a distillation apparatus.
It can be used for separation at higher temperature and higher pressure. In the vapor permeation method, a mixture of liquids is vaporized and then introduced into the separation membrane, so impurities contained in the feed solution and impurities are added.
In the liquid state, the influence of substances forming aggregates and oligomers on the membrane can be reduced. The zeolite membrane composite of the present invention can also be suitably used for the vapor permeation method.

When separating at a high temperature by the vapor permeation method, generally, the higher the temperature and the higher the concentration of the less permeable component in the mixture, for example, in the case of a mixture of an organic compound and water, the organic compound The higher the concentration, the lower the separation performance, but the zeolite membrane composite of the present invention can exhibit high separation performance even at a high temperature and when the concentration of a component having low permeability in the mixture is high. And since the vapor permeation method usually vaporizes the liquid mixture and then separates it, separation under more severe conditions is required, and the durability of the zeolite membrane composite is also required. The zeolite membrane composite of the present invention has durability that allows separation even under high temperature conditions, and is therefore suitable for the vapor permeation method.

The apparatus used for separating the gas mixture by the vapor permeation method is not particularly limited, but it is usually preferable to use it as a module (separation membrane module). The separation membrane module may be, for example, an apparatus as schematically shown in FIG.

In FIG. 3, the liquid to be separated 13 is sent to the vaporizer 15 at a predetermined flow rate by the liquid feed pump 14, and the entire amount is vaporized by heating in the vaporizer 15 to become a gas to be separated. The gas to be separated is a constant temperature bath 1
It is introduced into the zeolite membrane composite module 17 in 6 and supplied to the outside of the zeolite membrane composite. The zeolite membrane composite module 17 contains the zeolite membrane composite in a housing. The inside of the zeolite membrane composite is decompressed by the vacuum pump 21. The pressure difference from the gas to be separated is usually about 1 atm. The inner pressure can be measured with a Pirani gauge (not shown). Due to this pressure difference, water, which is a permeating substance, permeates the zeolite membrane composite in the gas to be separated. The permeated substance is collected by the permeation liquid collection trap 19. On the other hand, the non-permeated components in the gas to be separated are liquefied and collected by the trap 18 for collecting the liquid to be separated.

(Separation performance)
The zeolite membrane composite of the present invention is excellent in chemical resistance, oxidation resistance, heat stability and pressure resistance, exhibits high permeation performance and separation performance, and has excellent durability. Especially inorganic gas,
It exhibits excellent separation performance for the separation of lower hydrocarbons.

The high permeation performance referred to here means a sufficient amount of processing, and for example, the permeance [mol · (m ² · s · Pa) ^-1 ] of the gas component that permeates the membrane is, for example, carbon dioxide. When permeated at a temperature of 50 ° C. and a differential pressure of 0.1 MPa, it is usually 1 × ^10-9 or more.
It is preferably 5 × 10 ^-8 or more, more preferably 1 × 10 ^-7 or more, and the upper limit is not particularly limited and is usually 1 × 10 ^-4 or less.

Further, the permeence [mol · (m ² · s · Pa) ^{-1 ] is usually 2 × 10 -7} or less, preferably 1 × 10 ^-8 or less, more preferably 1 × 10 -8 or less, when methane is permeated under the same conditions, for example. 5 × and ^{10 -9} or less, although ideally Pamiensu is 0, practically ¹⁰ -10 to 1
It may be on the order of ^{0-14 or more.}

Here, the permeance (also referred to as “permeance”) is obtained by dividing the amount of permeated substance by the product of the film area, time, and the difference in voltage division between the supply side and the permeation side of the permeating substance. The unit is [mol · (m ² · s · Pa) ^-1 ], which is a value calculated by the method described in the section of Examples.

The selectivity of the zeolite membrane is represented by the ideal separation coefficient and the separation coefficient. The ideal separation coefficient and the separation coefficient are indexes generally used in membrane separation and represent selectivity, and are values calculated by the method described in the section of Examples.

The ideal separation coefficient is, for example, usually 10 or more, preferably 20 or more, more preferably 30 or more, still more preferably 40 or more, particularly preferably when carbon dioxide and methane are permeated at a temperature of 50 ° C. and a differential pressure of 0.1 MPa. Is 50 or more. The upper limit of the ideal separation coefficient is the case where only carbon dioxide completely permeates, and in that case, it becomes infinite, but in practice, the separation coefficient may be about 100,000 or less.

The separation coefficient is usually about the same as the ideal separation coefficient when the two components are mixed at a molar ratio of 1: 1. For example, a mixed gas having a volume ratio of carbon dioxide and methane of 1: 1 is used at a temperature of 50 ° C.
When permeated at a differential pressure of 0.1 MPa, it is usually 10 or more, preferably 20 or more, more preferably 30 or more, still more preferably 40 or more, and particularly preferably 50 or more, similar to the ideal separation coefficient. The upper limit of the separation coefficient is a case where only carbon dioxide is completely permeated, and in that case, it becomes infinite, but in practice, the separation coefficient may be about 100,000 or less.

As described above, the zeolite membrane composite of the present invention is excellent in chemical resistance, oxidation resistance, heat stability, pressure resistance, high permeation performance, separation performance, and excellent durability, for example. It can be particularly preferably used as the following gas separation technique.

As carbon dioxide separation technology, landfill gas (about 60% methane, 40 carbon dioxide) generated by removing carbon dioxide from natural gas and landfilling organic matter such as domestic waste.
%, A small amount of nitrogen, water vapor content), carbon dioxide removal, etc. can be mentioned.

Hydrogen separation technology includes hydrogen recovery in the petroleum refining industry, hydrogen recovery / purification (mixture of hydrogen, carbon monoxide, carbon dioxide, hydrocarbons, etc.) in various reaction processes in the chemical industry, and production of high-purity hydrogen for fuel cells. and so on. Hydrogen production for fuel cells is obtained by a steam reforming reaction of methane, and requires separation of hydrogen from a mixed gas of _{H 2} , CO, CH ₄ , and H _{2 O.}

In addition, as an oxygen separation technology, production of oxygen-enriched gas from air (medical use, oxygen-enriched air for combustion, etc.), and as a nitrogen separation technology, production of nitrogen-enriched gas from air (explosion-proof, antioxidant, etc.) ), Steam separation (dehumidification of precision machinery, etc.), dissolution gas separation (deaeration from water and organic liquid)
, Organic gas separation (separation of organic gas in the petroleum refining industry and petrochemical industry, separation of olefins and paraffins) and the like.

Hereinafter, the present invention will be described in more detail based on Experimental Examples, but the present invention is not limited to the following Experimental Examples as long as the gist of the present invention is not exceeded. The values of various production conditions and evaluation results in the following experimental examples (preparation examples or examples) have meanings as preferable values of the upper limit or the lower limit in the embodiment of the present invention, and the preferable range is The range may be defined by a combination of the upper and lower limit values and the values of the following experimental examples (preparation examples or examples) or the values of the experimental examples (preparation examples or examples).

Further, in the following experimental examples, the physical characteristics and separation performance of the zeolite membrane were measured by the following methods unless otherwise specified.
(1) X-ray diffraction (XRD)
The XRD measurement was performed based on the following conditions.
-Device name: X'PertPro MPD manufactured by PANalytical in the Netherlands
・ Optical system specifications Incident side: Enclosed X-ray tube (CuKα)
Soller Slit (0.04rad)
Divergence Slit (Variable Slit)
)
Sample stand: XYZ stage
Light receiving side: Semiconductor array detector (X'Celerator)
Ni-filter
Soller Slit (0.04rad)
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: Continuus
Read width: 0.05 °
Counting time: 99.7 sec
Automatic variable slit (Automatic-DS): 1 mm (irradiation width)
Lateral divergence mask: 10 mm (irradiation width)

The X-rays were emitted in a direction perpendicular to the axial direction of the cylindrical tube. In addition, X-rays are not the lines in contact with the surface of the sample table, out of the two lines in which the cylindrical tubular membrane composite placed on the sample table and the surface parallel to the surface of the sample table are in contact with each other so as to minimize noise. , Mainly on the other line above the surface of the sample table.
In addition, the irradiation width is fixed at 1 mm with an automatically variable pickpocket, BR> B, and measured, and Materi
An XRD pattern was obtained by performing a variable slit-to-fixed slit conversion using the XRD analysis software JADE 7.5.2 (Japanese version) of alsData, Inc.

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

(3) XPS measurement XPS (X-ray photoelectron spectroscopy) measurement of 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-34W (X-ray generation area 170 μmφ)
-Charge neutralization: Electron gun (5 μA), ion gun (10 V) combined-Spectroscopic system: Pulse energy 187.85 eV @ wide spectrum
58.70eV @ narrow spectrum (Na1s, Al2p
, Si2p, K2p, S2p)
29.35eV @ wide spectrum (C1s, O1s, S
i2p)
-Measurement area: Spot irradiation (irradiation area <340 μmφ)
・ Extraction angle: 45 ° (from the surface)

(4) Amount of air permeation Under atmospheric pressure, one end of the zeolite membrane composite is sealed, and the other end is kept airtight.
Connected to the vacuum line of kPa, the flow rate of air permeated through the zeolite membrane composite was measured with a mass flow meter installed between the vacuum line and the zeolite membrane composite, and the air permeation amount [L / (
It was m ² · h)]. As the mass flow meter, 8300 manufactured by KOFLOC, for N2 gas, and a maximum flow rate of 500 ml / min (20 ° C., 1 atm equivalent) were used. KOFLOC 8
At 300, when the mass flow meter display is 10 ml / min (20 ° C, 1 atm equivalent) or less, Lintec's MM-2100M, for Air gas, maximum flow rate 20 ml /
It was measured using min (0 ° C., converted to 1 atm).

(5) Single component gas permeation test The single component gas permeation test was carried out as follows using the apparatus schematically shown in FIG. The sample gases used were carbon dioxide (purity 99.9%, manufactured by High Pressure Gas Industry Co., Ltd.) and methane (purity 99.
999%, manufactured by Japan Fine Products Co., Ltd., hydrogen (purity 99.99% or more, HORI
Generated from BASTEC hydrogen generator OPGU-2200), nitrogen (purity 99.99%,
(Made by Toho Oxygen Industry Co., Ltd.), Helium (purity 99.99, manufactured by Japan Helium Center Co., Ltd.).

In FIG. 1, the cylindrical zeolite membrane composite 1 is installed in a constant temperature bath (not shown) in a state of being stored in a stainless steel pressure-resistant container 2. A temperature control device is attached to the constant temperature bath so that the temperature of the sample gas can be adjusted.

One end of the cylindrical zeolite membrane composite 1 is sealed with a cylindrical endpin 3. The other end is connected by the connecting portion 4, and the other end of the connecting portion 4 is connected to the pressure resistant container 2. The inside of the cylindrical zeolite membrane composite and the pipe 11 for discharging the permeated gas 8 are connected via a connecting portion 4, and the pipe 11 extends to the outside of the pressure-resistant container 2. A pressure gauge 5 for measuring the pressure on the supply side of the sample gas is connected to any of the locations leading to the pressure-resistant container 2. Each connection is airtightly connected.

In the device of FIG. 1, when performing a single component gas permeation test, the sample gas (supply gas 7) is used.
The permeated gas 8 supplied between the pressure-resistant container 2 and the zeolite membrane composite 1 at a constant pressure and permeated through the zeolite membrane composite is measured by a flow meter (not shown) connected to the pipe 11.

The gas permeation test can also be performed as follows in the apparatus schematically shown in FIG.
In FIG. 2, the cylindrical zeolite membrane composite 1 is installed in a constant temperature bath (not shown) in a state of being stored in a stainless steel pressure-resistant container 2. A temperature control device is attached to the constant temperature bath so that the temperature of the sample gas can be adjusted.

One end of the cylindrical zeolite membrane composite 1 is sealed with a circular endpin 3. The other end is connected by a connecting portion 4, and the other end of the connecting portion 4 is connected to the pressure resistant container 2. The inside of the cylindrical zeolite membrane composite and the pipe 11 for discharging the permeated gas 8 are connected via a connecting portion 4, and the pipe 11 extends to the outside of the pressure-resistant container 2. In addition, the zeolite membrane composite 1 has
A pipe 12 for supplying the sweep gas 9 is inserted via the pipe 11. Further, a pressure gauge 5 for measuring the pressure on the supply side of the sample gas and a back pressure valve 6 for adjusting the pressure on the supply side are connected to any of the locations leading to the pressure resistant container 2. Each connection is airtightly connected.

In the device of FIG. 2, when performing a gas permeation test, a sample gas (supply gas 7) is supplied between the pressure-resistant container 2 and the zeolite membrane composite 1 at a constant flow rate, and the pressure on the supply side is supplied by the back pressure valve 6. Is constant, the flow rate of the exhaust gas discharged from the pipe 11 is measured.

More specifically, in order to remove components such as moisture and air, after drying at the measurement temperature or higher and purging with the exhaust gas or the supply gas used, the sample temperature and the supply gas of the zeolite membrane composite 1 After the differential pressure between the 7 side and the permeated gas 8 side is kept constant and the permeated gas flow rate is stable, the flow rate of the sample gas (permeated gas 8) that has permeated the zeolite membrane composite 1 is measured, and the gas permeence [mol. (M ² · s · Pa) ^-1 ] is calculated. The pressure difference (differential pressure) between the supply side and the permeation side of the supply gas is used as the pressure when calculating the permeence.

Based on the above measurement results, the ideal separation coefficient α is calculated by the following equation (1).
α = (Q1 / Q2) / (P1 / P2) (1)
[In the formula (1), Q1 and Q2 indicate the permeation amount [mol · (m ² · s) ^-1 ] of the highly permeable gas and the low permeable gas, respectively, and P1 and P2 are P1 and P2, respectively. The pressure [Pa] of the highly permeable gas and the low permeable gas as the supply gas is shown. ]

Further, when the separation coefficient α'is calculated in the separation of the mixed gas, it is calculated by the following formula (2).
α'= (Q'1 / Q'2) / (P'1 / P'2) (2)
[In formula (2), Q'1 and Q'2 indicate the permeation amount [mol · (m ² · s) ^-1 ] of the highly permeable gas and the low permeable gas, respectively, and P'1 And P'2, respectively
The pressure [Pa] of the highly permeable gas and the low permeable gas as the supply gas is shown. ]

(Preparation Example 1)
A CHA-type aluminosilicate zeolite was directly hydrothermally synthesized on the inorganic porous support to prepare an inorganic porous support-CHA-type zeolite membrane composite.
The reaction mixture for hydrothermal synthesis was prepared as follows.
1 mol / L-NaOH aqueous solution 44.1 g, 1 mol / L-KOH aqueous solution 29.0 g,
Aluminum hydroxide (containing 53.5% by mass of _{Al 2} O _{3, manufactured by Aldrich) 2.52}
g was added, and 591 g of water was further added and stirred to dissolve aluminum hydroxide. As an organic template, 13.5 g of an aqueous solution of N, N, N-trimethyl-1-adamantanammonium hydroxide (hereinafter referred to as "TMADAOH") (containing 25% by mass of TMADAOH, manufactured by Seichem) was added thereto. 60.0 g of colloidal silica (Snowtech-40 manufactured by Nissan Chemical Industries, Ltd.) was added and stirred for 2 hours to prepare an aqueous reaction mixture.

The composition (molar ratio) of this reaction mixture is SiO ₂ / Al ₂ O ₃ / NaOH / KOH / H ₂
O / TMADAOH = 1 / 0.033 / 0.11 / 0.073 / 100 / 0.04, Si
O ₂ / Al ₂ O ₃ = 30.

As the inorganic porous support, a porous alumina tube (outer diameter 12 mm, inner diameter 9 mm) was cut to a length of 400 mm, and then powder generated during cutting was removed by compressed air.

Seed crystals were attached to the support prior to hydrothermal synthesis. _{SiO 2} / Al ₂ O ₃ / NaOH / KOH / H ₂ O / TMADAOH = 1 / 0.033 / by the same method as the above method.
A CHA-type zeolite having a gel composition of 0.1 / 0.06 / 40 / 0.07 and crystallized by hydrothermal synthesis at 160 ° C. for 2 days and having a particle size of about 0.5 μm was used as a seed crystal.

The support was immersed in a demineralized water dispersed in about 0.3% by mass of the seed crystals for a predetermined time, and then dried at 100 ° C. for 4 hours or more to attach the seed crystals.

Teflon (registered trademark) containing two supports with seed crystals attached and the above aqueous reaction mixture.
Immerse vertically in the inner cylinder (800 ml), seal the autoclave, and at 160 ° C. 48
It was heated under spontaneous pressure in a stationary state for a long time. After a lapse of a predetermined time, the zeolite membrane composite was taken out from the reaction mixture after allowing to cool, washed, and dried at 100 ° C. for 4 hours or more.

After cutting each of these membrane complexes to 200 mm, in air and in an electric furnace, at 500 ° C.
It was fired for 5 hours. The average mass of the CHA-type zeolite crystallized on the support, which was determined from the difference between the mass of the membrane composite after firing and the mass of the support, was 196 g / m ² . The amount of air permeated after firing was 81 L / (m ² · h).

The XRD pattern of the produced zeolite membrane is shown in FIG. * In the figure is the peak derived from the support. From the XRD measurement, it was found that CHA-type zeolite was produced.
Powdered CHA Zeolite (SSZ-13 in US Pat. No. 4,544,538)
Zeolite, commonly referred to as "SSZ-13". ) Is shown in FIG.

From FIG. 4, it can be seen that the XRD pattern of the produced zeolite membrane has a significantly higher peak intensity near 2θ = 17.9 ° than the XRD pattern (FIG. 5) of SSZ-13, which is a powdered CHA-type zeolite. ..
For SSZ-13, which is a powdered CHA-type zeolite, (intensity of peak near 2θ = 17.9 °) / (intensity of peak near 2θ = 20.8 °) = 0.2, the formed zeolite membrane (Intensity of peak near 2θ = 17.9 °) / (Intensity of peak near 2θ = 20.8 °)
= 1.2, and the orientation to the (1,1,1) plane in the rhombohedral setting was inferred.

_{The SiO 2} / Al ₂ O ₃ molar ratio of the zeolite membrane measured by SEM-EDX was 34.

(Example 1)
The membrane composite obtained in Preparation Example 1 was cut into 40 mm, and Teflon (registered trademark) containing approximately 0.9 M of an iron nitrate aqueous solution in which 14.1 g of iron (III) nitrate 9hydrate was dissolved in 35 g of water. It was placed in an inner cylinder (100 ml). The autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under self-sustaining pressure. After a lapse of a predetermined time, the zeolite membrane composite was taken out from the aqueous solution after allowing to cool, washed, and dried at 100 ° C. for 4 hours or more.

The Fe / Al molar ratio on the surface of the zeolite membrane measured by XPS was 0.17.

A single component gas permeation test was performed using the above CHA-type zeolite membrane composite treated with an aqueous iron nitrate solution. The evaluated gases are carbon dioxide, methane, hydrogen, nitrogen and helium.

_{First, as a pretreatment, CO 2} is introduced as a supply gas 7 at 140 ° C. between the cylinder of the pressure vessel 2 and the zeolite membrane composite 1, and the pressure is about 0.16 MPa.
The inside of the cylinder of the zeolite membrane composite 1 is set to 0.098 MPa (atmospheric pressure), and 70
After drying for more than a minute, it was confirmed that the amount of _{CO 2 permeated did not change.}

After that, the pressure on the supply side was set to 0.20 MPa, and the supply gas was changed to each evaluation gas. At this time, the differential pressure between the supply gas 7 side and the permeation gas 8 side of the zeolite membrane composite 1 was 0.1 MPa.

Then, the temperature was set to 50 ° C., and after the temperature became stable, the supply gas was changed to each evaluation gas. At this time, the differential pressure between the supply gas 7 side and the permeation gas 8 side of the zeolite membrane composite 1 was 0.1 MPa.

Table 1 shows the permeence and separation coefficient of each gas at 50 ° C. thus obtained.
Table 2 shows the permeence and separation coefficient of each gas at 40 ° C.

(Example 1: Permeation test example)
The single component gas permeation test was carried out in the same manner as in Example 1 except that the membrane composite obtained in Preparation Example 1 was cut to 40 mm and used without treatment with an aqueous iron nitrate solution. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 1, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 2.

As shown in the results of Tables 1 and 2, CO ₂ / CH ₄ and H ₂ / CH _{4 were treated with an aqueous iron nitrate solution.}
, It was confirmed that each separation coefficient of _{CO 2} / N _{2 was sufficiently increased.}

(Preparation Example 2)
A CHA-type aluminosilicate zeolite was directly hydrothermally synthesized on the inorganic porous support to prepare an inorganic porous support-CHA-type zeolite membrane composite.
The reaction mixture for hydrothermal synthesis was prepared as follows.
1 mol / L-NaOH aqueous solution 12.0g, 1mol / L-KOH aqueous solution 8.0 g, aluminum hydroxide to a mixture of water 115g _{(Al 2} O 3 53.5 mass% containing, Aldrich) and 0.306g In addition, it was stirred and dissolved to prepare a transparent solution. As an organic template, N, N, N-trimethyl-1-adamantanammonium hydroxide (
Hereinafter, this will be referred to as "TMADAOH". ) Aqueous solution (containing 25% by mass of TMADAOH,
2.7 g (manufactured by Seichem) was added, and 12.0 g of colloidal silica (Snowtech-40 manufactured by Nissan Chemical Industries, Ltd.) was further added and stirred for 2 hours to prepare an aqueous reaction mixture.

The composition (molar ratio) of this reaction mixture is SiO ₂ / Al ₂ O ₃ / NaOH / KOH / H ₂
O / TMADAOH = 1 / 0.01 / 0.15 / 0.1 / 100 / 0.04, SiO ₂ /
Al ₂ O ₃ = 100.

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 then dried.

As a seed crystal, SiO ₂ / Al ₂ O ₃ / NaOH / KOH / H ₂ O / TMADAOH =
With a gel composition (molar ratio) of 1 / 0.066 / 0.15 / 0.1 / 100 / 0.04, hydrothermal heat at 160 ° C. for 2 days in the presence of a porous alumina tube (outer diameter 12 mm, inner diameter 9 mm). A CHA-type zeolite obtained by filtering, washing with water, and drying the synthetically produced precipitate was used. The particle size of the seed crystal was about 2 to 4 μm.

After immersing the support in an alkaline aqueous solution containing 0.33% by mass of NaOH and 0.31% by mass of KOH at about 1% by mass for a predetermined time, the seed crystal is immersed at 100 ° C. for 4 hours or more. It was dried and the seed crystals were attached. The mass increase after drying was 9.9 g / m ² .

The support to which the seed crystal is attached is vertically immersed in a Teflon (registered trademark) inner cylinder (200 ml) containing the above aqueous reaction mixture, the autoclave is sealed, and the autoclave is allowed to stand at 160 ° C. for 48 hours. Then, it was heated under the autoclave. After a lapse of a predetermined time, the support-zeolite membrane composite was taken out from the reaction mixture after allowing to cool, washed, and dried at 100 ° C. for 4 hours or more.

This membrane composite was calcined in air at 500 ° C. for 10 hours in an electric furnace. At this time, both the temperature rising rate and the temperature lowering rate were set to 0.5 ° C./min. The mass of the CHA-type zeolite crystallized on the support, which was determined from the difference between the mass of the membrane composite after firing and the mass of the support, was 122 g / m ² . The amount of air permeated after firing was 570 L / (m ² · h).

The XRD pattern of the produced zeolite membrane is shown in FIG. * In the figure is the peak derived from the support. From the XRD measurement, it was found that CHA-type zeolite was produced. Also (2θ
= Intensity of peak near 9.6 °) / (Intensity of peak near 2θ = 20.8 °) = 3.4,
(Intensity of peak near 2θ = 17.9 °) / (Intensity of peak near 2θ = 20.8 °) =
It was 0.34. Compared with the XRD pattern of the powdered CHA-type zeolite of FIG. 5, the XRD pattern of the zeolite membrane obtained in Preparation Example 2 is (the intensity of the peak near 2θ = 17.9 °).
/ (Intensity of peak near 2θ = 20.8 °) is about the same, while (2θ = 9.6 °)
(Intensity of peak in the vicinity) / (Intensity of peak in the vicinity of 2θ = 20.8 °) is high, rhombohedral
The orientation to the (1,0,0) plane in the setting was inferred.

_{The SiO 2} / Al ₂ O ₃ molar ratio of the zeolite membrane measured by SEM-EDX is 4
It was 0.2.

(Example 2)
The membrane composite obtained in Preparation Example 2 was cut into 30 mm, and made of Teflon (registered trademark) containing a 0.2 M aqueous iron nitrate solution in which 2.12 g of iron (III) nitrate 9hydrate was dissolved in 25 g of water. Inner cylinder (
100 ml). The autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under self-sustaining pressure. After a lapse of a predetermined time, the support-zeolite membrane composite was taken out from the aqueous solution after allowing to cool, washed, and dried at 100 ° C. for 4 hours or more.

Then, the single component gas permeation test was carried out in the same manner as in Example 1. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 3, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 4.

(Example 2: Permeation test example)
A single component gas permeation test was carried out in the same manner as in Example 1 except that the membrane composite obtained in Preparation Example 2 was cut to 40 mm and used without being treated with an aqueous iron nitrate solution. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 3, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 4.

As shown in the results of Tables 3 and 4, it was confirmed that the separation coefficient was sufficiently increased by the treatment with the iron nitrate aqueous solution even in the zeolite membrane composite having a small amount of aluminum such that _{the SiO 2} / Al ₂ O _{3 molar ratio was 40.2.} ..

(Preparation Example 3)
A CHA-type aluminosilicate zeolite was directly hydrothermally synthesized on the inorganic porous support to prepare an inorganic porous support-CHA-type zeolite membrane composite.
The reaction mixture for hydrothermal synthesis was prepared as follows.
1 mol / L-NaOH aqueous solution 60.1 g, 1 mol / L-KOH aqueous solution 40.0 g,
Aluminum hydroxide (containing 53.5% by mass of _{Al 2} O _{3, manufactured by Aldrich) 5.03}
G was added, and 574 g of water was further added and stirred to dissolve aluminum hydroxide. As an organic template, 13.5 g of an aqueous solution of N, N, N-trimethyl-1-adamantanammonium hydroxide (hereinafter referred to as "TMADAOH") (containing 25% by mass of TMADAOH, manufactured by Seichem) was added thereto. 60.1 g of colloidal silica (Snowtech-40 manufactured by Nissan Chemical Industries, Ltd.) was added and stirred for 2 hours to prepare an aqueous reaction mixture.

The composition (molar ratio) of the aqueous reaction mixture is SiO ₂ / Al ₂ O ₃ / NaOH / KOH / H ₂
O / TMADAOH = 1 / 0.066 / 0.15 / 0.1 / 100 / 0.04, SiO ₂
/ Al ₂ O ₃ = 15.

CHA crystallized on the support obtained from the difference between the mass of the film composite after firing and the mass of the support
The average mass of the type zeolite was 116 g / m ² . In addition, the amount of air permeation after firing is 1.
It was 20 L / (m ² · h).

The XRD pattern of the produced zeolite membrane is shown in FIG. * In the figure is the peak derived from the support. From the XRD measurement, it was found that CHA-type zeolite was produced.
From FIG. 7, it can be seen that the XRD pattern of the produced zeolite membrane has a significantly higher peak intensity near 2θ = 17.9 ° than the XRD pattern (FIG. 5) of SSZ-13, which is a powdered CHA-type zeolite. ..

For SSZ-13, which is a powdered CHA-type zeolite, (intensity of peak near 2θ = 9.6 °) / (intensity of peak near 2θ = 20.8 °) = 5.7, of the produced zeolite membrane (Intensity of peak near 2θ = 17.9 °) / (Intensity of peak near 2θ = 20.8 °) =
It was 6.4, and the orientation toward the (1,0,0) plane and the (1,1,1) plane in the rhombohedral setting was estimated.

(Example 3)
The membrane composite obtained in Preparation Example 3 was cut into 40 mm, and an inner cylinder made of Teflon (registered trademark) containing about 1 M aqueous solution of lanthanum nitrate in which 15.2 g of lanthanum nitrate hexahydrate was dissolved in 31.2 g of water. It was placed in (100 ml). Seal the autoclave and let it stand at 100 ° C for 1 hour.
It was heated under self-sustaining pressure. After a lapse of a predetermined time, the zeolite membrane composite was taken out from the aqueous solution after allowing to cool, washed, and dried at 100 ° C. for 4 hours or more.

Then, the single component gas permeation test was carried out in the same manner as in Example 1. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 5, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 6.

(Example 4)
The membrane composite obtained in Preparation Example 3 was cut into 40 mm, and an inner cylinder made of Teflon (registered trademark) containing an approximately 1 M aqueous solution of chromium nitrate in which 14.0 g of chromium nineahydrate nitrate was dissolved in 29.3 g of water. It was placed in (100 ml). The autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under self-sustaining pressure. After a lapse of a predetermined time, the zeolite membrane composite was taken out from the aqueous solution after allowing to cool, washed, and dried at 100 ° C. for 4 hours or more.

Then, the single component gas permeation test was carried out in the same manner as in Example 1. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 5, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 6.

(Example 5)
The membrane complex obtained in Preparation Example 3 was cut to 40 mm, and zirconyl nitrate 2 was added to 33.9 g of water.
Teflon (registered trademark) containing about 1 M aqueous solution of zirconyl nitrate in which 9.6 g of hydrate is dissolved.
It was placed in an inner cylinder (100 ml). The autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under self-sustaining pressure. After a lapse of a predetermined time, the zeolite membrane composite was taken out from the aqueous solution after allowing to cool, washed, and dried at 100 ° C. for 4 hours or more.

Then, the single component gas permeation test was carried out in the same manner as in Example 1. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 5, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 6.

(Example 6)
The membrane composite obtained in Preparation Example 3 was cut into 40 mm, and an inner cylinder made of Teflon (registered trademark) containing about 1 M magnesium nitrate aqueous solution in which 8.9 g of magnesium nitrate hexahydrate was dissolved in 31.2 g of water. It was placed in (100 ml). The autoclave was sealed and heated at 100 ° C. for 1 hour in a stationary state under self-sustaining pressure. After a lapse of a predetermined time, the zeolite membrane composite was taken out from the aqueous solution after allowing to cool, washed, and dried at 100 ° C. for 4 hours or more.

Then, the single component gas permeation test was carried out in the same manner as in Example 1. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 5, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 6.

(Example 7)
The membrane composite obtained in Preparation Example 3 was cut into 40 mm, and an inner cylinder made of Teflon (registered trademark) containing about 1 M gallium nitrate aqueous solution in which 14.0 g of gallium nitrate octahydrate was dissolved in 30.0 g of water. It was placed in (100 ml). Seal the autoclave and let it stand at 100 ° C for 1 hour.
It was heated under self-sustaining pressure. After a lapse of a predetermined time, the zeolite membrane composite was taken out from the aqueous solution after allowing to cool, washed, and dried at 100 ° C. for 4 hours or more.

Then, the single component gas permeation test was carried out in the same manner as in Example 1. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 5, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 6.

(Example 8)
The membrane treated with the approximately 1 M aqueous solution of lanthanum nitrate obtained in Example 3 was washed, dried, and then calcined at 300 ° C. for 4 hours.

Then, the single component gas permeation test was carried out in the same manner as in Example 1. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 5, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 6.

(Example 9)
The membrane treated with the approximately 1 M magnesium nitrate aqueous solution obtained in Example 6 was washed and dried, and then 300.
It was calcined at ° C. for 4 hours.

Then, the single component gas permeation test was carried out in the same manner as in Example 1. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 5, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 6.

(Example 10)
The film treated with the approximately 1 M gallium nitrate aqueous solution obtained in Example 7 was washed, dried, and then calcined at 300 ° C. for 4 hours.

Then, the single component gas permeation test was carried out in the same manner as in Example 1. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 5, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 6.

(Example 3: Permeation test example)
A single component gas permeation test was carried out in the same manner as in Example 1 except that the membrane composite obtained in Preparation Example 3 was cut to 40 mm and used without being treated with an aqueous solution of a metal nitrate. The permeence and separation coefficient of each gas at 50 ° C. obtained are shown in Table 5, and the permeence and separation coefficient of each gas at 140 ° C. are shown in Table 6.

The present invention can be used in any industrial field, but requires separation of a gas mixture (gas) such as a chemical industry plant, a natural gas refining plant, or a plant that generates biogas from garbage. Especially suitable in the field where water is separated from a hydrous organic compound such as a chemical industry plant, a fermentation plant, a precision electronic parts factory, a battery manufacturing factory, etc., and recovery of the organic compound is required. Can be used.

1: Zeolite membrane composite 2: Pressure-resistant container 3: End pin 4: Connection part 5: Pressure gauge 6: Back pressure valve 7: Supply gas 8: Permeated gas 9: Sweep gas 10: Exhaust gas 11: Permeated gas discharge pipe 12: Sweep gas introduction pipe 13: Liquid to be separated 14: Liquid feed pump 15: Vaporizer 16: Constant temperature bath 17: Zeolium membrane composite module 18: Trap for collecting liquid to be separated 19: Trap for collecting permeate 20: Cold trap 21: Vacuum pump

Claims (4)

A method for producing a porous support-zeolite membrane composite having a zeolite membrane containing a divalent or higher valent metal excluding Al on an inorganic porous support.
The zeolite in the zeolite membrane is a CHA-type zeolite.
The porous support-zeolite membrane composite is used for separating a gas mixture containing carbon dioxide.
The zeolite film is formed on an inorganic porous support, at least one metal selected from the group consisting of divalent or higher valent metal except Al in the zeolite membrane the concentration of the metal source compound 0.05-3 Immerse the zeolite membrane (membrane composite) formed on the inorganic porous support in a solution of mol / L.
Spray the solution onto the membrane complex,
Alternatively, a method for producing a metal-containing zeolite membrane composite, which comprises adding the solution to the membrane composite by dropping it and then firing it at a temperature of 500 ° C. or lower. The method for producing a metal-containing zeolite membrane composite according to claim 1, wherein the membrane composite is immersed in the solution at 0 to 180 ° C. The metal-containing zeolite membrane according to claim 1 or 2, wherein the zeolite membrane is formed by crystallizing zeolite on an inorganic porous support by hydrothermal synthesis using an aqueous reaction mixture containing an organic template. Method for producing a complex. The method for producing a metal-containing zeolite membrane composite according to any one of claims 1 to 3, wherein the porous support-zeolite membrane composite is used for separating carbon dioxide and methane.

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