JP2006281068A - Adsorbent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adsorbent with high adsorption performance applicable to various kinds of base material. <P>SOLUTION: The adsorbent comprises flat plate-like zeolite in which an average particle diameter (D) is in a range of 0.05-1.0 μm, average thickness (T) is in a range of 0.01-0.25 μm and (D)/(T) is 4 or more and which is ion-exchanged by an ion of at least one kind of an element selected from Group 1B, Group 2B, Group 3A, Group 7A and Group 8 or carries the metal of the element. The element is one kind or more selected from the group consisting of Cu, Ag, Zn, La, Ce, Mn, Co, Ni, Fe and a mixed rare earth element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an adsorbent comprising a fine plate-like zeolite. More specifically, the present invention relates to an adsorbent having high adsorption performance and applicable to various substrates.

  Zeolites (crystalline aluminosilicates) have been widely used industrially as adsorbents, treating agents, catalysts, catalyst supports and the like.

The zeolite used in such an application is a synthetic zeolite and is a dihedral polyhedral particle having a particle diameter on the order of submicron to several tens of microns.
In many cases, such zeolites are not used as fine powder zeolites as they are. In many cases, it is usually used in the form of pellets or spheres. However, conventional zeolites are often difficult to form alone, and are usually formed into a desired shape by adding a binder (binding material).

  When producing a zeolite compact, for example, it is known to add kaolin-type clay, an inorganic dispersant or the like as a binder to zeolite powder (Japanese Patent Laid-Open No. 2001-226167 (Patent Document 1)). No. 2001-261330 (Patent Document 2)).

Also disclosed is a method for producing a zeolite microsphere by crystallization of a raw material mixture mainly composed of a silica source, an alumina source, an alkali source and water, followed by crystallization. (JP-A-2-149417 (Patent Document 3))
Further, JP-A-6-64916 (Patent Document 4) discloses a method for producing a particularly fine spherical molded body as a method for molding zeolite. Specifically, granulation core particles composed of zeolite and an inorganic binder are charged into a tumbling granulator, and a granulated fine powder composed of zeolite fine powder and an inorganic binder whose moisture has been adjusted in advance. Spherical zeolite compacts are obtained by supplying fine particles for granulation to core particles and supplying water as a granulation medium.
JP 2001-226167 A JP 2001-261330 A JP-A-2-149417 JP-A-6-64916

(The problem is to clarify the problem)
However, in the conventional molded body, the strength is insufficient and wears and pulverizes in use, and the moldability is not good, so the binder component is used, but this reduces the zeolite content and the effectiveness of the zeolite. In some cases, sufficient adsorption performance or the like cannot be obtained.

  In particular, when used for the treatment of a fluid containing a sulfur compound or the like, there are many conventional molded articles that pass through without contacting with the adsorbent, and the treatment efficiency is poor.

Therefore, as a result of intensive studies to solve the above-mentioned problems, the present inventors have used flat zeolite as the zeolite powder and have been ion-exchanged with a specific metal ion or supported with a specific metal. It was found that the adsorption performance of sulfur compounds is excellent, and when such a zeolite is used as a molded product, it exhibits excellent strength and high adsorption performance, and the amount of leakage of untreated fluid is extremely small. The invention has been completed.

  Moreover, it has been found that such a plate-like zeolite can be used as an adsorbent even in a powder form without being formed into a compact and can be blended in various members such as a sheet. As described above, conventional dice-like zeolite cannot be used as it is in powder form. For this reason, a method has been adopted in which a catalyst component is supported on a compact.

That is, the aspects of the present invention are as follows.
[1] The average particle diameter (D) is in the range of 0.05 to 1.0 μm,
The average thickness (T) is in the range of 0.01 to 0.25 μm, (D) / (T) is 4 or more,
It is characterized by comprising a plate-like zeolite which is ion-exchanged with ions of one or more elements selected from Group 1B, Group 2B, Group 3A, Group 7A, Group 8 or a metal of the element supported thereon. Adsorbent.
[2] The adsorbent of the adsorbent according to [1], wherein the element is at least one selected from the group consisting of Cu, Ag, Zn, La, Ce, Mn, Co, Ni, Fe, and mixed rare earths.
[3] The adsorbent according to [2], wherein the element is Ag or Cu.
[4] The adsorbent according to [1] to [3], wherein the zeolite is a faujasite type zeolite.
[5] The adsorbent according to [1] to [4], wherein the specific surface area of the zeolite is in a range of 300 to 1000 m ² / g.

The inventors first mix and heat an aqueous SiO ₂ —Al ₂ O ₃ composite oxide sol having a specific oxide molar ratio and a gel-like aggregate suspension having a specific oxide molar ratio. Has proposed that a flat, fine zeolite can be obtained. (Japanese Unexamined Patent Application Publication No. 2004-315338)
However, this publication does not suggest what kind of component should be supported when used as an adsorbent.

  The adsorbent according to the present invention contains a specific flat zeolite. Since this flat zeolite is flat and small, when it is made into a molded body, it can form a high-strength molded body, and when it is made into a film, film formability and film strength are improved. Has an effect. Furthermore, the adsorptivity can be improved by improving the diffusion effect.

Therefore, according to the present invention, since the adsorption performance of the sulfur compound is particularly excellent and the plate is in the shape of a plate, an adsorbent in which the adsorbate is difficult to pass through is provided regardless of whether it is a molded body or a film.
Furthermore, since flat zeolite is highly transparent and can be used for a transparent substrate, it can be used as a sheet-like adsorbent.

Hereinafter, preferred embodiments of the present invention will be described.
The adsorbent according to the present invention comprises a specific flat zeolite.
Flat zeolite The zeolite used in the present invention has (1) an average particle diameter (D) in the range of 0.05 to 1.0 μm and an average thickness (T) in the range of 0.01 to 0.25 μm. Yes,
(D) / (T) is a flat plate shape having 4 or more.

In such a shape, when a paint is prepared by dispersing it in a paint resin and applied onto a substrate, the adhesion and adhesion to various substrates are high, and the strength of the film is also high. .
When the ratio (D / T) of the average particle diameter (D) to the average thickness (T) is less than 4, there is no substitute for ordinary dice-like zeolite, and a thin film is formed using such zeolite particles. However, the film-forming property is lowered and the adhesion and adhesion to various substrates are insufficient, and the strength of the film may be insufficient. The upper limit of (D / T) is not particularly limited, but it becomes more brittle as it becomes larger.

  When the average particle diameter (D) of the plate-like zeolite exceeds 1.0 μm, the average thickness (T) simultaneously exceeds 0.25 μm, and it is difficult to obtain a fine plate-like zeolite. Even if there is no place to replace ordinary polyhedral (octahedron, etc.) zeolite, even if a thin film is formed using such zeolite particles, the adhesion and adhesion to various substrates will be insufficient, The strength may be insufficient.

It is difficult to obtain a flat zeolite having an average particle diameter (D) of less than 0.05 μm. Even if obtained, the crystallinity is low and the adsorption performance may be insufficient.
The average particle diameter (D) of the plate-like zeolite is more preferably 0.05 to 0.5 μm, and further preferably 0.1 to 0.5 μm.

The average thickness (T) of the plate-like zeolite is appropriately selected according to the average particle diameter (D) and (D / T) ratio. When the particle diameter exceeds 0.25 μm, the average thickness (T) is normal as described above. There is no substitute for dice-like adsorbents. Moreover, it is difficult to obtain a film having an average thickness (T) of less than 0.01 μm.

  Further, the shape observation and (D / T) of zeolite are obtained as an average value by measuring at least 100 shapes and measuring (D) and (T) from an electron micrograph. In the present invention, it is desirable that the zeolite having a hexagonal plate-like shape among all zeolite particles is 60% or more, preferably 80% or more, more preferably 90% or more.

  The flat zeolite used in the present invention is preferably a faujasite type zeolite made of silica / alumina. In addition, the faujasite type zeolite is easy to obtain a plate-like zeolite, and among the zeolites, the pore size of the fine pores is as large as about 8 mm, so that relatively large adsorbate molecules can be adsorbed.

The zeolite used in the present invention is represented by the following general formula (1).
_{XM 2 / n O · Al 2} O 3 · YSiO 2 ··· (1)
(M: a cation, n: valency of the cation, X: number of moles of the metal oxide when the Al ₂ O ₃ was 1 mol, Y: a SiO ₂ when the Al ₂ O ₃ and 1 mole Moles)
The zeolite skeleton is usually shown as follows: aluminum (+ trivalent) and silicon (+4 valent) share oxygen (-2 valence) with each other, so that silicon is electrically neutral, Becomes −1. In order to neutralize this negative charge, a cation (usually Na ion in synthetic zeolite) is required in the framework.

In the present invention, such a cation is exchanged with another ion, or the element of the exchanged ion is in a metal state.
The amount of ions and / or metals supported is preferably such that X is in the range of 0.05 to 1, more preferably 0.1 to 0.8. As described above, alkali metal ions such as sodium may remain, and the amount of alkali metal ions (corresponding to 1-X in the above formula) is in the range of 0.95 or less, and further 0.9 or less. It is desirable.

  That is, the content of ion-exchanged cations and supported metals (including both ion-exchanged and metallized materials) is 1 to 40% by weight, further 2 to 30% by weight in terms of metal. It is preferable that it exists in the range.

  When the content is small, there is substantially no difference from the absence of the content, and the adsorption performance for the adsorbate containing oxygen, sulfur, and nitrogen tends to be insufficient. Further, it is difficult to make the content more than the above range, and even if it is metalized and supported, the metal is aggregated, the particle size is increased, and the adsorption performance is not further improved. Depending on the case, if the coarse particles are dispersed, the adsorption performance may be lowered accordingly.

The number of moles Y of SiO ₂ is preferably in the range of 2 to 30, more preferably 3 to 10. Those having a small amount of Y cannot be obtained as crystalline zeolite. If Y is too large, the ion exchange capacity is low, the ion exchange amount at the above limit becomes insufficient, and sufficient adsorption performance may not be obtained.

The amount ratio of X and Y corresponds to the alumina content, the silica content, and the alkali metal content when preparing the flat zeolite, and the charge ratio is substantially the same as the composition of the flat zeolite.
That is, the amount of X may be such that the amount of alkali metal hydroxide charged in the zeolite raw material becomes a desired composition ratio. The charge amount will be described later.

  The numerical value of Y is directly proportional to the alumina content and the silica content when preparing the flat zeolite. If the silica content increases, a flat zeolite with a large Y can be obtained. Further, when the alkali content increases, Y tends to decrease.

In the present invention, the cation in the plate-like zeolite is ion-exchanged to ions of one or more elements selected from 1B group, 2B group, 3A group, 7A group, and 8 group, Alternatively, the metal of the element is supported. Among these elements, among them, at least one selected from the group consisting of Cu, Ag, Zn, La, Ce, Mn, Co, Ni, Fe, mixed rare earths, especially Cu and / or Ag.
Is preferred. Usually, the ion-exchanged cation is ion-bonded, but may be at least partially reduced to a metal. It should be noted that the cation ion-exchanged in the plate-like zeolite does not always have a clear boundary as to whether it exists in an ionic bond or is in a metallic state. However, it is considered that the cations are converted to metal by heating after ion exchange.

The specific surface area of the tabular zeolite used in the present invention, 300~1000m ² / g, more preferably in the range of 500 to 1000 m ² / g. When the specific surface area is small, sufficient adsorption performance may not be obtained. It is difficult to obtain a product having a large specific surface area. If it exists in this range, while being excellent in processing efficiency, the intensity | strength of a molded object can also be made high. Here, the specific surface area is measured by the BET method.

Further, the specific surface area of the plate-like zeolite that is ion-exchanged or metal-supported varies depending on the amount of ion-exchange and the amount of metal supported, but is generally 200 to 1000 m ² / g, more preferably 300 to 1000 m ² / It is preferable to be in the range of g.

Such a plate-like zeolite is not particularly limited as long as it has the above average particle diameter, composition and the like, but can be obtained by, for example, the following method described in JP-A-2004-315338.

First, a flat zeolite is produced.
The flat zeolite is not particularly limited as long as it has the above average particle diameter, composition, and the like, but can be obtained by the following method, for example.

(A) Fine particles of dispersoids are M ₂ O / Al ₂ O ₃ = 2.0 to 5.0 in terms of oxide molar composition ratio.
SiO ₂ / Al ₂ O ₃ = 5 to 16
_{H 2 O / Al 2 O 3} = 2000~5000
A matrix that is an aqueous SiO ₂ —Al ₂ O ₃ composite oxide sol in the range of (where M represents an alkali metal);
(B) M ₂ O / Al ₂ O ₃ = 15 ± 3 in terms of oxide molar composition ratio
SiO ₂ / Al ₂ O ₃ = 17 ± 3
_{H 2 O / Al 2 O 3} = 100~2000
A gel-like aggregate suspension in the range of (where M represents an alkali metal),
(C) The molar ratio of the alkali metal oxide (M ₂ O / Al ₂ O ₃ ) to the total Al ₂ O ₃ is 8.0
In the case where the alkali metal oxide is insufficient so as to be in the range of 12.0, an insufficient alkali source is added and mixed,
(D) The resulting mixture can be obtained by heating and aging at a temperature at which crystallization occurs for a time sufficient for crystallization. The aqueous SiO ₂ —Al ₂ O ₃ composite oxide sol that is the matrix has a dispersoid content. The fine particles are in an oxide molar composition ratio.
M ₂ O / Al ₂ O ₃ = 2.0 to 5.0, preferably 2.5 to 4.5
_{SiO 2 / Al 2 O 3 =} 5~16 preferably 8 to 11
H ₂ O / Al ₂ O ₃ = 2000 to 5000, preferably 3000 to 4000
It is desirable that the dispersoid concentration be in the range of 0.1 to 40% by weight (where M represents an alkali metal). In the case of the SiO ₂ —Al ₂ O ₃ composite oxide sol in which the oxide molar composition ratio of the fine particles of the dispersoid is out of the above range, a desired zeolite may not be obtained. The aqueous SiO ₂ —Al ₂ O ₃ composite oxide sol is a sol in which fine particles containing silica and alumina are dispersed in water and the dispersoid concentration is adjusted to 1.5% by weight. The amount of solids that settled when the sol was processed with a centrifuge at 3500 rpm for 10 minutes was 0.5 vol% or less. The gel aggregate of (b) is crystallized as it is, but when mixed in a matrix and heat-aged, crystals are obtained, that is, it has a function as a nucleus or a seed.

Such a SiO ₂ —Al ₂ O ₃ composite oxide sol is produced, for example, by the method described in JP-A-5-132309. That is, an alkali metal, ammonium or organic base silicate and an alkali-soluble alumina compound are simultaneously added to an alkaline aqueous solution having a pH of 10 or more at a predetermined ratio, and the colloid is controlled without controlling the pH of the reaction solution. Particles can be generated to prepare a SiO ₂ —Al ₂ O ₃ composite oxide sol.

Fine particles which are a dispersoid of the aqueous SiO ₂ —Al ₂ O ₃ composite oxide sol have a particle size of 0.
. It is desirable to be in the range of 005 to 0.2 μm. When the particle size of the fine particles is smaller than 0.005 μm, the composite oxide sol may be inferior in stability, and when larger than 0.2 μm, the desired zeolite cannot be obtained. There is. The desirable particle size of the fine particles is in the range of 0.01 to 0.1 μm.

The gel-like aggregate suspension (hereinafter sometimes referred to as gel-form aqueous solution) has an oxide molar composition ratio of M ₂ O / Al ₂ O ₃ = 15 ± 3, preferably 14 ± 2.
SiO ₂ / Al ₂ O ₃ = 17 ± 3, preferably 16 ± 2
H ₂ O / Al ₂ O ₃ = 100 to 2000, preferably 200 to 1000
A liquid reaction mixture of a silica source, an alumina source and an alkali source in the range (where M represents an alkali metal) is preferably at a temperature of 10 to 80 ° C, more preferably at a temperature of 20 to 40 ° C. Preferably, it is an aqueous suspension of gel-like aggregates (aggregates in which gel-like microparticles are slightly aggregated) prepared by aging without stirring, preferably 2 hours or more, more preferably 6-24 hours . The gel aqueous solution preferably has an oxide molar composition in the above range and a particle diameter in the range of 0.5 to 10 μm. If the oxide molar composition of the gel aggregate suspension is outside the above range, the desired zeolite may not be obtained.

The aqueous SiO ₂ —Al ₂ O ₃ composite oxide sol as the matrix and the gel aqueous solution are mixed, and an alkali metal oxide (M ₂ O / Al ₂ O ₃ ) with respect to the total Al ₂ O ₃ is mixed. When the alkali metal oxide is insufficient such that the molar ratio is in the range of 8.0 to 12.0, the insufficient alkali source is added and mixed, and the resulting mixture is a temperature at which crystallization occurs. And aging for a time sufficient for crystallization. Examples of the alkali source include sodium hydroxide, sodium aluminate and potassium hydroxide. In addition, the above-mentioned SiO ₂ —Al ₂ O ₃ composite oxide sol as a matrix and the above gel aqueous solution are mixed to obtain an alkali metal oxide (M ₂ O / Al ₂ O for all Al ₂ O ₃₎ . _When the molar ratio of ₃ ) is in the range of 8.0 to 12.0, it is not necessary to add an alkali source.

When the molar ratio of the alkali metal oxide (M ₂ O / Al ₂ O ₃ ) to the total Al ₂ O ₃ is outside the range of 8.0 to 12.0 in the above mixture, p-type zeolite or gmelinite It is not preferable because zeolite that cannot adsorb the adsorbate described later may be by-produced.

The molar ratio of Al ₂ O ₃ of the gel-like aqueous solution and the mixing ratio of the above-described aqueous composite oxide sol as a matrix in the composite oxide sol of Al ₂ O ₃ and matrix in the gel-like aqueous solution is The range of 1: 0.5 to 1: 1.5 is desirable. When this ratio is less than 1: 0.5, it takes a long time to crystallize the zeolite, and when it exceeds 1: 1.5, crystallization can be done in a short time, but the silica silica A large amount of alumina source is used, which is not economical.

The reaction mixture obtained by mixing the aqueous SiO ₂ —Al ₂ O ₃ composite oxide sol as a matrix with the gel aqueous solution and the alkali source at a temperature at which crystallization occurs by a well-known method. Heat aging for sufficient time for crystallization. In general, heat aging is performed at a temperature of 80 ° C. or higher, preferably 95 to 98 ° C. for 1 to 200 hours. The oxide molar composition ratio of the aforementioned reaction mixture is desirably in the following range.

M ₂ O / Al ₂ O ₃ = 5.0 to 15.0, preferably 7.0 to 12.0
SiO ₂ / Al ₂ O ₃ = 6-20, preferably 8-18
H ₂ O / Al ₂ O ₃ = 1000 to 3000, preferably 1500 to 2500
The zeolite crystallized by heat aging of the reaction mixture is recovered by separating the filtrate, washing and drying by a well-known method. Thus, the flat zeolite used for this invention can be obtained. At this time, sodium ions derived from the raw material are present as cations and are usually referred to as NaY zeolite.

The cation (usually Na ion) of the flat zeolite is exchanged for a predetermined ion.
The adsorbent may be ion-exchanged using a molded body that has been molded in advance, or the powdered plate-like zeolite may be ion-exchanged, or the plate-like zeolite after ion exchange may be formed. In addition, the shaping | molding method in the case of setting it as a molded object is mentioned later.

Ion Exchange and Metal Loading Method A zeolite compact or a plate-like zeolite is dispersed in water, and this dispersion is stirred and a metal salt or an aqueous metal salt solution is added thereto for ion exchange. It is preferable to adjust the pH of the zeolite compact or the plate-like zeolite dispersion at the time of ion exchange to 3 to 7, more preferably 4 to 6, although it depends on the type of metal salt. When the pH of the zeolite compact dispersion is less than 3, the crystal structure of the zeolite may be destroyed.

When the pH of the dispersion exceeds 7, although depending on the type of metal salt, the added metal salt is likely to precipitate as a hydroxide, which may make it difficult to exchange metal ions.
To adjust the pH of the zeolite compact dispersion, an acid or an alkali may be added to the dispersion. Mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid can be used as the acid. The alkali includes an alkali metal hydroxide, Alkali carbonate, ammonia or the like can be used.

  As the metal salt, metal salts of the above elements can be used, for example, copper sulfate, copper nitrate, silver nitrate, zinc sulfate, zinc nitrate, gallium nitrate, lanthanum sulfate, lanthanum nitrate, cerium sulfate, cerium nitrate, manganese nitrate, Cobalt sulfate, cobalt nitrate, nickel sulfate, nickel nitrate, and palladium nitrate can be used.

  The metal salt is preferably added so that the amount of the cation to be ion exchanged or the amount of the metal to be supported is the above-described amount. In general, the metal salt is preferably added in a larger amount than the composition ratio of X in the formula (1) from the viewpoint of ion exchange, and is usually in the range of 0.1 to 5 mol, preferably 0.3 to 2 mol. Is desirable.

The temperature at the time of ion exchange is usually from room temperature to 98 ° C., and the time is from 0.5 hours to 12 hours.
The zeolite is then filtered and washed. In addition, after washing | cleaning, ion exchange can be performed similarly to the above. By carrying out repeated ion exchange, the amount of ions and / or metals supported can be increased.

  Filter, wash and dry. Moreover, you may bake or reduce | restore as needed. When firing, it is preferably performed at 200 to 800 ° C., preferably 300 to 600 ° C., usually for about 0.5 to 12 hours.

  When the calcination temperature is low, there are many adsorbed waters of zeolite, and sufficient adsorption performance may not be obtained. Even if the firing temperature is high, the adsorption performance may be insufficient because most of the metal ions become oxides. Moreover, when it reduces, although it changes with carrying | support metal seed | species, it is preferable to carry out reduction processing for about 0.5 to 12 hours normally at 150-500 degreeC, Preferably it is 200-400 degreeC by reducing gas atmosphere, such as hydrogen.

  If the reduction temperature is low, metal ions may not be sufficiently reduced to become metal, or sufficient adsorption performance may not be obtained. Even if the reduction temperature is too high, aggregation of supported metal or particle growth may occur, resulting in insufficient adsorption performance.

The plate-like zeolite loaded with ions and / or metals thus obtained can be used as an adsorbent as it is, but can also be used as a molded body.
In addition, when ion-exchanged as powder without forming, the plate-like zeolite after ion exchange is dried, formed and dried, and then calcined or reduced, or the calcined or reduced plate-like zeolite May then be shaped, then dried, then calcined or reduced.

Zeolite Molding Method The zeolite molding method is not particularly limited as long as a zeolite molded body that can be used as an adsorbent is obtained, and conventionally known methods can be employed.

  For example, a binder component is added to the zeolite dispersion, a molding aid (sometimes referred to as a plasticizer), a surfactant, etc. are added as necessary, and the dispersion is spray-dried as necessary to obtain a moisture content. Is prepared from 10 to 40% by weight, preferably 15 to 30% by weight of zeolite powder. This is used as a core particle. The core particles are prepared by mixing zeolite, water and, if necessary, a molding aid, adjusting the water content to about 30 to 45% by weight, kneading sufficiently, and then preparing pellets by extrusion molding. Although such a pellet can be used as a core particle as it is, it can also be used as a spherical core particle by putting the pellet in a granulator and rotating it.

  Next, the zeolite powder is attached to the core particles to grow the particles. For example, by preparing zeolite powder in the same manner as the preparation of the core particles, putting the core particles into a granulator, and continuously supplying the zeolite powder and water while rotating the granulator. Nuclear particles can be grown.

The amount of zeolite powder supplied can be adjusted according to the desired size of the zeolite compact, and the amount of water supplied can be determined appropriately while observing the state of the zeolite powder adhering to the core particles and the presence / absence of aggregation of the core particles. As the binder component, clay minerals such as kaolin, montmorillonite, bentonite, allophane, sepiolite, oxides such as alumina, silica / alumina, and composite oxides are used. Such a binder preferably has a particle size in the range of approximately 10 nm to 2 μm, and particularly preferably smaller than the particle size of the zeolite used. Further, the shape is not particularly limited, and may be any of spherical, fibrous, and irregular shapes.

Among the binders used in the present invention, fibrous binders such as bentonite and alumina are excellent in moldability, and a zeolite molded body excellent in strength, wearability and the like can be obtained.
In particular, an alumina binder has a large pore volume, is excellent in wear resistance, and can produce a zeolite compact excellent in compressive strength even if the particle diameter is small.

  The amount of the binder component used is preferably such that the content of the binder in the obtained zeolite compact is in the range of 2 to 30% by weight, more preferably 5 to 15% by weight as the solid content. If it exists in this range, the intensity | strength and the molded object which was excellent in the adsorptivity can be manufactured efficiently.

  Examples of the molding aid include crystalline cellulose, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, starch, and lignin. When a molding aid is added, the optimum moisture width at the time of molding is widened and the moldability is improved.

The amount of the molding aid added is preferably in the range of 0.5 to 15% by weight, more preferably 1 to 10% by weight of the total solid content (total of zeolite, binder, etc.). When the addition amount of the molding aid is less than 0.5% by weight of the total solid content, the effect of adding the molding aid cannot be sufficiently obtained, and the addition amount of the molding aid is 15% of the total solid content. If it exceeds wt%, the strength and wear resistance of the resulting molded product tend to decrease.

  As another method, zeolite, water, and a molding aid as necessary are mixed, the water content is adjusted to approximately 30 to 45% by weight, and after sufficiently kneaded, pellets are prepared by extrusion molding. . Such pellets can be used as spherical particles by putting them in a granulator and rotating them.

In addition, when using a molded object as an adsorbent, the following molded objects are preferable.
In the case of a spherical molded body, the average particle diameter (D) is preferably in the range of approximately 0.3 to 5 mm. A more preferable range is 1 to 3 mm. When the average particle size is small, the pressure loss of the adsorption tower becomes large when used as an adsorbent, which may make operation difficult. Moreover, even if the particles are too large, the effectiveness factor may decrease depending on the use conditions, and sufficient performance may not be exhibited when used as a catalyst or an adsorbent.

Further, when a pellet-shaped article, the average diameter of the pellets (D _P) is substantially 0.3~5m
The average length (L _P ) of the pellets is preferably in the range of 0.3 to 20 mm. When the average diameter (D _P ) is small, when used as an adsorbent, the pressure loss of the adsorption tower becomes large, which may make operation difficult. Also, when extruding pellets, extrusion may be difficult due to the small hole diameter of the dies. Also, the average diameter (D _P
) Has a large effectiveness factor depending on use conditions, and may not exhibit sufficient performance when used as a catalyst or an adsorbent. A more preferable range of the average diameter (D _P ) is 0.
. It is the range of 7-3 mm. Further, when the average length (L _P ) is shortened, the pellet is not formed, and the moldability is difficult. If the average length (L _P ) is too large, the porosity at the time of filling increases, so that the performance when used as an adsorbent or a catalyst may not be sufficiently exhibited. A more preferable range of the average diameter (L _P ) is a range of 1.5 to 6 mm.

  The pore volume (PV) of the molded body is preferably in the range of 0.1 to 0.6 ml / g, more preferably 0.2 to 0.5 ml / g. When the pore volume (PV) is small, the pores of the zeolite are clogged, and the zeolite is not effectively used. For this reason, the performance as an adsorbent may be insufficient. Even if the pore volume (PV) is increased, the strength of the molded product tends to decrease, and may be pulverized at the time of use and cause trouble of the apparatus.

  The above-mentioned pore volume in the present invention is measured by a mercury distribution method pore distribution measuring device (manufactured by QUANTA CHROME: AUTOSCAN-60 POROSOMETER, mercury contact angle 130 ° C., mercury surface tension 473 Dyn / cm 2, measurement range “high pressure”). can do.

The zeolite compact has a bulk specific gravity (CBD) of 0.5 to 1.5 g / cc, and more preferably 0.5.
It is preferably in the range of 6 to 1.2 g / cc. If the bulk specific gravity (CBD) is small, the pore volume may be large and the particle strength may be insufficient. Further, even if the bulk specific gravity (CBD) is large, the pore volume becomes small and the adsorptive capacity becomes insufficient.

  In the present invention, the bulk specific gravity is determined by filling a 100 cc graduated cylinder with about 100 cc of a zeolite compact, measuring the volume of the zeolite compact after moderately vibrating, and determining the weight (g) of the filled compact as the zeolite. It can be determined by dividing by the volume of the compact.

The specific surface area of the zeolite shaped bodies, the type of zeolite to be used may vary depending on the ratio and the like, 100~900m ² / g, more preferably in the range of 200-700 ² / g. When the specific surface area is less than 100 m ² / g, the adsorption capacity is insufficient, and the specific surface area is 90
It is difficult to obtain a product exceeding 0 m ² / g. The specific surface area can be measured by the BET method using N ₂ .

Examples of the adsorbate that can be adsorbed on the adsorbent according to the present invention include organic compounds containing one or more elements selected from oxygen, sulfur, and nitrogen.
Examples of the organic compound containing oxygen include acetaldehyde, formaldehyde, nonenal, and mercaptan. The adsorbent of the present invention is also effective for hydrogen sulfide.

Examples of the organic compound containing nitrogen include trimethylamine, triethylamine, pyridine, and indole. It is also effective against ammonia.
Examples of the organic compound containing sulfur include methyl mercaptan, ethyl mercaptan, methyl sulfide, ethyl sulfide, methyl disulfide, and ethyl disulfide.

The adsorbent of the present invention is particularly excellent in sulfur compound adsorption performance.
When the adsorbent according to the present invention is used as a molded article, the strength is high, it can be used even at high temperatures, and powdering is also low, so that the filling efficiency can be increased. When the molded body is used, for example, an adsorbent according to the present invention may be filled in an adsorption tower and a fuel gas containing a sulfur compound may be circulated, which is suitable for fuel gas pretreatment of a vehicle fuel cell.

  When using a flat zeolite powder as an adsorbent as it is, if the adsorbate is dissolved in a solvent, the powder is dispersed and adsorbed, and then separated or attached directly to the support Or adhering with an adhesive and using as an adsorbent.

Furthermore, since flat zeolite is highly transparent and can be used for a transparent substrate, it can be used as a sheet-like adsorbent.
According to the present invention, since a plate-like zeolite is used, an adsorbent in which the adsorbate is difficult to pass through is provided regardless of whether it is a molded body or a film.

[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by a following example, unless the summary is exceeded.

Example 1
Preparation of Ag-exchanged NaY-type zeolite (A) for adsorbent (preparation of gelled aqueous solution)
Sodium aluminate solution 57.0 containing 17% by weight of Na ₂ O and 22% by weight of Al ₂ O ₃
While stirring the mixture, 187.4 g of a 37.2 wt% aqueous sodium hydroxide solution was added as Na ₂ O. While stirring the solution, 549.8 g of No. 3 water glass having a silica concentration of 24% by weight was added to 205.8 g of pure water at 20 ° C. and 8.1 g / min. Its composition is Na ₂ O / Al ₂ O ₃ = 16.0 in terms of oxide molar ratio.
SiO ₂ / Al ₂ O ₃ = 17.9
H ₂ O / Al ₂ O ₃ = 332
Met. This was stirred for about 1 hour and then allowed to stand at 30 ° C. for 16 hours to obtain an aqueous solution containing gel aggregates. The particle size of the gel aggregate in this case was in the range of 1.0 to 5.0 μm.

(Preparation of complex oxide sol as matrix)
40.4 g of silica sol having an average particle size of 50 mm and a silica concentration of 20% by weight was added to 2864.0 pure water.
The one diluted with g was heated to 80 ° C. In this diluted sol, 279.5 g of No. 3 water glass (24.0 wt% as SiO ₂₎ was diluted with 3356.4 g of pure water, and 62.9 g of 22.0 wt% sodium aluminate (Al ₂ O ₃₎ was purified. Diluted with 3574.0 g of water was added simultaneously over 4 hours. Further, 111.0 g of 3 wt% sodium hydroxide was added as Na ₂ O over 1 hour. Meanwhile, the temperature of the diluted sol was kept at 80 ° C. After completion of the addition, the sol was cooled to room temperature to obtain 9000 g of a SiO ₂ —Al ₂ O ₃ composite oxide sol.

The result of measuring the dispersoid fine particles of this composite oxide sol based on the chemical analysis method was the following composition. The water content was determined from the loss on ignition at 1000 ° C. for 1 hour.
Na ₂ O / Al ₂ O ₃ = 4.3
SiO ₂ / Al ₂ O ₃ = 9.1
H ₂ O / Al ₂ O ₃ = 3660
In this case, the composite oxide sol had a particle size of 0.02 to 0.04 μm.
(Preparation of reaction mixture)
While stirring 9000 g of the SiO ₂ —Al ₂ O ₃ composite oxide sol as a matrix, 1000 g of the gelled aqueous solution was added and stirred and mixed at room temperature for 30 minutes. The composition of the gel-like reaction mixture thus obtained has an oxide molar ratio of Na ₂ O / Al ₂ O ₃ = 9.9.
SiO ₂ / Al ₂ O ₃ = 12.5
H ₂ O / Al ₂ O ₃ = 2072
Met.

This gel-like reaction mixture was transferred to a crystallization tank and aged by heating and aging at 95 to 98 ° C. for 72 hours without stirring. After completion of aging, the crystal product was taken out, filtered and washed to obtain NaY-type zeolite (A). At this time, the Al ₂ O ₃ content in the solid content was 21.4 wt%, the SiO ₂ content was 65.5 wt%, the Na ₂ O content was 13.0 wt%, and the SiO ₂ / Al ₂ O ₃ molar ratio was 5 0.00.
(Ag ion exchange)
100 g of this NaY-type zeolite is dispersed in 1000 g of pure water, and the pH is adjusted to 5.5 to 6.0 with an aqueous nitric acid solution having a concentration of 10% by weight while stirring. Separately, 39.4 g of silver nitrate is dissolved in 1000 g of pure water, and a pH-adjusted NaY-type zeolite suspension slurry is added with stirring. After the addition, the slurry temperature was adjusted to 60 ° C., stirred for 1 hour, filtered, washed, and then dried to obtain an Ag-exchanged NaY zeolite (A) carrying 20% by weight of Ag.

For the Ag-exchanged NaY-type zeolite (A), the composition, specific surface area by BET method, shape observation by electron microscope, particle diameter, and particle thickness were determined, and the results are shown in Table 1.
Preparation of adsorbent (A) The obtained Ag-exchanged NaY-type zeolite (A) dry powder was mixed with 45 g of alumina sol (manufactured by Catalyst Kasei Kogyo Co., Ltd .: AP-1, Al ₂ O ₃ concentration 70 wt%) and crystalline cellulose 2 Add weight%, put in a kneader with a steam jacket and stir until the water content is 38 wt%. This was extruded to 2 mmφ. This was dried and calcined at 600 ° C. for 3 hours to obtain an adsorbent (A).
Performance Evaluation A stainless steel reaction tube having an inner diameter of 28.4 mm was filled with 30 g of the adsorbent (A).
Subsequently, methyl mercaptan gas (concentration 6.6 ppm) was supplied as an adsorption gas so that the space velocity (SV) was 32,000 h ⁻¹ . At this time, the pressure was maintained at normal pressure and the temperature was maintained at 25 ± 3 ° C.

The amount of methyl mercaptan adsorbed was determined as follows. The concentration of methyl mercaptan in the outlet gas is analyzed by gas chromatography, and the concentration of methyl mercaptan is 0.5.
At the time of reaching ppm, the supply of methyl mercaptan was stopped. The adsorption amounts up to this time are integrated, and the results are shown in Table 1 as weight percent with respect to the adsorbent (A). Table 1 shows the results with the time until the concentration of methyl mercaptan at the outlet becomes 0.5 ppm as the breakthrough time.

Example 2
Preparation of Ag-exchanged NaY-type zeolite (B) for adsorbent (preparation of gelled aqueous solution)
Sodium aluminate solution 57.0 containing 17% by weight of Na ₂ O and 22% by weight of Al ₂ O ₃
With stirring to 18 g, 187.4 g of a 37.2 wt% aqueous sodium hydroxide solution as Na ₂ O was added. While stirring this solution, it was added at 20 ° C. and 8.1 g / min to a solution obtained by adding 549.8 g of No. 3 water glass having a silica concentration of 24% by weight to 205.8 g of pure water. Its composition is Na ₂ O / Al ₂ O ₃ = 16.0 in terms of oxide molar ratio.
SiO ₂ / Al ₂ O ₃ = 17.9
H ₂ O / Al ₂ O ₃ = 332
Met. This was stirred for about 1 hour and then allowed to stand at 30 ° C. for 16 hours to obtain an aqueous solution containing gel aggregates. The particle size of the gel aggregate in this case was in the range of 1.0 to 5.0 μm.
(Preparation of complex oxide sol as matrix)
40.4 g of silica sol having an average particle size of 50 mm and a silica concentration of 20% by weight was added to 2864.0 pure water.
The one diluted with g was heated to 80 ° C. In this diluted sol, 279.5 g of No. 3 water glass (24.0 wt% as SiO ₂₎ was diluted with 3356.4 g of pure water, and 62.9 g of 22.0 wt% sodium aluminate (Al ₂ O ₃₎ was purified. Diluted with 3574.0 g of water was added simultaneously over 4 hours. Further, 111.0 g of 3 wt% sodium hydroxide was added as Na ₂ O over 1 hour. Meanwhile, the temperature of the diluted sol was kept at 80 ° C. After completion of the addition, the sol was cooled to room temperature to obtain 9000 g of a SiO ₂ —Al ₂ O ₃ composite oxide sol.

The result of measuring the dispersoid fine particles of this composite oxide sol based on the chemical analysis method was the following composition. The water content was determined from the loss on ignition at 1000 ° C. for 1 hour.
Na ₂ O / Al ₂ O ₃ = 4.3
SiO ₂ / Al ₂ O ₃ = 9.5
H ₂ O / Al ₂ O ₃ = 3660
In this case, the composite oxide sol had a particle size of 0.02 to 0.04 μm.
(Preparation of reaction mixture)
While stirring 9000 g of the SiO ₂ -Al ₂ O ₃ composite oxide sol as a matrix, 1000 g of the gelled aqueous solution was added and stirred and mixed at room temperature for 30 minutes. The composition of the gel-like reaction mixture thus obtained has an oxide molar ratio of Na ₂ O / Al ₂ O ₃ = 9.9.
SiO ₂ / Al ₂ O ₃ = 10.3
H ₂ O / Al ₂ O ₃ = 2072
Met.

This gel-like reaction mixture was transferred to a crystallization tank and aged by heating and aging at 95 to 98 ° C. for 72 hours without stirring. After completion of aging, the crystal product was taken out, filtered, washed and dried to obtain NaY-type zeolite (B). At this time, the Al ₂ O ₃ content in the solid content was 24.5% by weight, the SiO ₂ content was 62.0% by weight, the Na ₂ O content was 14.9% by weight, SiO ₂ / Al ₂ O ₃
The molar ratio was 4.20.

Then, ion exchange was carried out in the same manner as in Example 1, and Ag exchange N carrying 20% by weight Ag.
aY-type zeolite (B) was obtained.
For the Ag-exchanged NaY-type zeolite (B), the composition, specific surface area by BET method, shape observation by electron microscope, particle diameter, and particle thickness were determined, and the results are shown in Table 1.
Preparation of adsorbent (B) An adsorbent (B) was obtained in the same manner as in Example 1 except that Ag-exchanged NaY zeolite (B) was used.
Performance Evaluation An adsorption test was conducted in the same manner as in Example 1. The results of the adsorption test are shown in Table 1.

Example 3
Preparation of Ag-exchanged NaY-type zeolite (C) for adsorbent In Example 1, except that the addition amount of silver nitrate was changed to 17.5 g, ion exchange was performed in the same manner, and an Ag-exchanged NaY-type zeolite carrying 10% by weight of Ag. (C) was obtained.

For the Ag-exchanged NaY-type zeolite (C), the composition, specific surface area by BET method, shape observation by electron microscope, particle diameter, and particle thickness were determined, and the results are shown in Table 1.
Preparation of adsorbent (C) Adsorbent (C) was obtained in the same manner as in Example 1 except that Ag-exchanged NaY-type zeolite (C) was used.
Performance Evaluation An adsorption test was conducted in the same manner as in Example 1. The results of the adsorption test are shown in Table 1.

Example 4
Preparation of Ag-exchanged NaY-type zeolite (D) for adsorbent In Example 1, ion-exchange was performed in the same manner except that the amount of silver nitrate added was 68 g, and Ag-exchanged NaY-type zeolite (D) carrying 30 wt% Ag. Got.

For the Ag-exchanged NaY-type zeolite (D), the composition, specific surface area by BET method, shape observation by electron microscope, particle diameter, and particle thickness were determined.
Preparation of adsorbent (D) Adsorbent (D) was obtained in the same manner as in Example 1 except that Ag-exchanged NaY zeolite (D) was used.
Performance Evaluation An adsorption test was conducted with the same formulation as in Example 1. The results of the adsorption test are shown in Table 1.

Example 5
Preparation of adsorbent (E) 100 g of Ag-exchanged NaY-type zeolite (A) obtained in the same manner as in Example 1, and 45 g of alumina sol (manufactured by Catalyst Chemical Industry Co., Ltd .: AP-1, Al ₂ O ₃ concentration 70 wt%) And pure water 1000g
Is added and mixed with stirring. This mixed slurry was spray-dried to obtain a 20 wt% binder-added Ag-exchanged NaY-type zeolite powder.

While rotating a granulator (produced by Fuji Powder Co., Ltd .: Malmerizer, diameter 200 mm) at 500 rpm, an Ag-exchanged NaY-type zeolite powder spray-dried and water are gradually supplied to prepare a spherical molded body, Subsequently, the adsorbent (E) was prepared by baking at 600 ° C. for 3 hours. In the adsorbent (E), almost no agglomerated particles were observed, and the particles were spherical particles having an average particle diameter of 3 mm.
Performance Evaluation An adsorption test was conducted with the same formulation as in Example 1. The results of the adsorption test are shown in Table 1.

Example 6
Preparation of Cu-exchanged NaY-type zeolite (F) for adsorbent 100 g of NaY-type zeolite (A) obtained in the same manner as in Example 1 was dispersed in 1000 g of pure water, and the pH was adjusted with a 10% by weight sulfuric acid aqueous solution while stirring. Adjusted to 5.5-6.0. To this, 43.6 g of copper sulfate pentahydrate was added, and after addition, the slurry temperature was raised to 60 ° C., stirred for 1 hour, filtered, washed, and Cu-exchanged NaY type carrying 10% by weight of Cu. Zeolite (F) was obtained.

For the Cu-exchanged NaY-type zeolite (F), the composition, specific surface area by BET method, shape observation by electron microscope, particle diameter, and particle thickness were determined, and the results are shown in Table 1.
Preparation of adsorbent (F) An adsorbent (F) was obtained in the same manner as in Example 1 except that the Cu-exchanged NaY zeolite (F) was used.
Performance Evaluation An adsorption test was conducted with the same formulation as in Example 1. The results of the adsorption test are shown in Table 1.

Example 7
Preparation of adsorbent (G) 100 g of Ag-exchanged NaY-type zeolite (A) obtained in the same manner as in Example 1, and 16 g of alumina sol (manufactured by Catalyst Chemical Industry Co., Ltd .: AP-1, Al ₂ O ₃ concentration 70 wt%) Further, 2% by weight of crystalline cellulose was added, and the mixture was placed in a kneader with a steam jacket and stirred until the water content was 39% by weight. This was extruded to 2 mmφ. This was dried and calcined at 600 ° C. for 3 hours to obtain an adsorbent (G).
Performance evaluation An adsorption test was carried out using the same formulation as in Example 1. The results of the adsorption test are shown in Table 1.

Comparative Example 1
Preparation of NaY-type zeolite (H) for adsorbent (preparation of gelled aqueous solution)
Sodium aluminate solution 463. containing 17% by weight of Na ₂ O and 22% by weight of Al ₂ O ₃
To 6 g, 3771.2 g of a 21.35 wt% aqueous sodium hydroxide solution was added with stirring. This solution was added to 3675 g of No. 3 water glass having a silica concentration of 24% by weight with stirring to generate gel aggregates. The composition of the liquid containing the gel-like aggregate is Na ₂ O / Al ₂ O ₃ = 15.9 in terms of oxide molar ratio.
SiO ₂ / Al ₂ O ₃ = 14.7
H ₂ O / Al ₂ O ₃ = 330
Met. Furthermore, after stirring this for about 1 hour, it left still at 30 degreeC for 12 hours, and obtained the liquid containing a gel-like aggregate. The particle size of the gel aggregate in this case was in the range of 1.0 to 5.0 μm.
(Preparation of complex oxide sol as matrix)
809.3 g of silica sol containing 30 wt% as SiO ₂ was diluted with 295.9 g of pure water, and this sol was mixed with 1023.4 g of No. 3 water glass having a silica concentration of 24 wt%. Next, 455.5 g of sodium aluminate solution containing 17% by weight of Na ₂ O and 22% by weight of Al ₂ O ₃ was added to this solution while stirring to obtain a gel-like reaction product having the following oxide composition. It was. In this case, the particle size of the gel-like reaction product was 5.0 to 10.0 μm.

Na ₂ O / Al ₂ O ₃ = 2.56
SiO ₂ / Al ₂ O ₃ = 8.29
H ₂ O / Al ₂ O ₃ = 103.9
(Preparation of reaction mixture)
While stirring, 139.5 g of the liquid containing the gel-like aggregate was added to the gel-like reaction product, and the mixture was stirred and mixed at room temperature for 3 hours. The composition of the gel-like reaction mixture thus obtained has an oxide molar ratio of Na ₂ O / Al ₂ O ₃ = 2.8.
SiO ₂ / Al ₂ O ₃ = 8.4
H ₂ O / Al ₂ O ₃ = 108
Met.

This was transferred to a crystallization tank and aged by heating at 95 to 98 ° C. for 50 hours. After completion of aging, the crystal product was taken out, filtered and washed to obtain NaY-type zeolite (H). At this time, the Al ₂ O ₃ content in the solid content was 21.7 wt%, the SiO ₂ content was 65.1 wt%, the Na ₂ O content was 13.2 wt%, and the SiO ₂ / Al ₂ O ₃ molar ratio was 5 .10.

This NaY type zeolite (H) was Ag exchanged according to the same formulation as in Example 1 to obtain an Ag exchanged NaY type zeolite (H).
For the Ag-exchanged NaY-type zeolite (H), the composition, specific surface area by BET method, shape observation by electron microscope, particle diameter, and particle thickness were determined, and the results are shown in Table 1.
Preparation of adsorbent (H) Adsorbent (H) was obtained in the same manner as in Example 1 except that Ag-exchanged NaY zeolite (H) was used.
Performance Evaluation An adsorption test was conducted with the same formulation as in Example 1. The results of the adsorption test are shown in Table 1.

Comparative Example 2
Preparation of adsorbent (I) The adsorbent (I) is a spherical particle having an average particle diameter of 3 mmφ in the same manner as in Example 5 except that the Ag-exchanged NaY zeolite (H) obtained in the same manner as in Comparative Example 1 was used. Got.
Performance Evaluation An adsorption test was conducted with the same formulation as in Example 1. The results of the adsorption test are shown in Table 1.

Example 8
Preparation of adsorbent (J) 100 g of NaY type zeolite (A) obtained in Example 1 and 45 g of alumina sol (manufactured by Catalyst Chemical Industry Co., Ltd .: AP-1, Al ₂ O ₃ concentration 70 wt%) and crystals Add 2% by weight of water-soluble cellulose, add a kneader with a steam jacket and add water until the water content is 38% by weight while stirring. This was extruded to 2 mmφ. This was dried and calcined at 600 ° C. for 3 hours to obtain a NaY-type zeolite molded product.

  100 g of this NaY-type zeolite is dispersed in 1000 g of pure water, and the pH is adjusted to 5.5 to 6.0 with a 10% by weight aqueous nitric acid solution while stirring. Separately, 39.4 g of silver nitrate is dissolved in 1000 g of pure water, and a pH-adjusted NaY-type zeolite suspension slurry is added with stirring. The dispersion temperature was adjusted to 60 ° C. and stirred for 1 hour, followed by filtration and washing to obtain an adsorbent (J) carrying 20% by weight of Ag.

For the adsorbent (J), the composition, specific surface area by BET method, shape observation by electron microscope, particle diameter, and particle thickness were determined, and the results are shown in Table 1. In addition, a composition shows the value converted per zeolite from the analysis value.
Performance Evaluation An adsorption test was conducted with the same formulation as in Example 1. The results of the adsorption test are shown in Table 1.

Comparative Example 3
Preparation of Adsorbent (K) The NaY-type zeolite (H) obtained in Comparative Example 1 was subjected to Cu exchange in the same manner as in Example 6 to obtain a Cu—NaY-type zeolite.

This was subjected to 2 mmφ extrusion molding in the same manner as in Comparative Example 1 to obtain an adsorbent (K). Performance Evaluation An adsorption test was conducted with the same formulation as in Example 1. The results of the adsorption test are shown in Table 1.

Claims (5)

The average particle diameter (D) is in the range of 0.05 to 1.0 μm,
The average thickness (T) is in the range of 0.01 to 0.25 μm, (D) / (T) is 4 or more,
It is characterized by comprising a plate-like zeolite which is ion-exchanged with ions of one or more elements selected from Group 1B, Group 2B, Group 3A, Group 7A, Group 8 or a metal of the element supported thereon. Adsorbent. The element is selected from the group consisting of Cu, Ag, Zn, La, Ce, Mn, Co, Ni, Fe, mixed rare earths 1
The adsorbent according to claim 1, wherein the adsorbent is a species or more. The adsorbent according to claim 2, wherein the element is Ag or Cu. The adsorbent according to any one of claims 1 to 3, wherein the zeolite is a faujasite type zeolite. The adsorbent according to any one of claims 1 to 4, wherein a specific surface area of the zeolite is in a range of 300 to 1000 m ² / g.