JPH05146683A - Catalyst and production thereof - Google Patents

Abstract

PURPOSE:To obtain a catalyst capable of removing foul smell or harmful gases continuously over an extended period of time without raising excessively the temp. around the catalyst by a method wherein the structure of the catalyst is made up by forming on the surface of its base material a covering layer consisting of at least an activated alumina, zeolite, platinum group metal and inorg. binder. CONSTITUTION:The catalyst comprises a base material 2 (e.g. silica tube) and a catalyst covering layer 3 consisting of at least an activated alumina, zeolite, platinum group metal and inorg. binder formed on the surface of the base material 2. By alterately repeating the adsorption of odoriferous components with the zeolite and the alumina during the non-hating period and the regeneration by heating of the zeolite and the alumina and the catalytic decomposition of the odoriferous components during the heating period, the foul smell can be removed continuously over an extended period of time without raising excessively the temp. around the catalyst.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst body used for deodorization in equipment for heating, hot water supply, drying, cooking, refrigerating, air conditioning, incineration and the like.

[0002]

2. Description of the Related Art Conventionally, a method of arranging activated carbon in a room to adsorb gaseous malodorous substances and deodorize them has been mainly used. Further, recently, a method has been taken in which a device having an ozone generating function is arranged in a room and odorous components are oxidatively decomposed by ozone gas.

[0003]

[Problems to be Solved by the Invention] These malodorous substances are
It is mainly ammonia, fatty acids, unsaturated hydrocarbons, sulfur-containing organic compounds such as mercaptans, nitrogen-containing organic compounds and the like, which are generated by physiological actions such as sweat of living humans and decomposition of foods. In the conventional adsorption using activated carbon, the adsorption capacity varies depending on the odor component species, and the adsorption capacity is limited.Because the moisture in the atmosphere interferes with the adsorption of malodorous gas, the activated carbon is changed regularly. There is a problem that it is necessary to do so. In addition, the odor decomposition method using ozone requires that a special device be provided to control the optimum ozone generation concentration for decomposition and deodorization, that there are odor component species that are difficult to decompose by ozone, and that the ozone generator The problem is that it has a lifetime.

The present invention has been made to solve the above-mentioned problems of the prior art, and provides a function of completely removing odors and harmful gases in a room with a simple structure and with a long life.

[0005]

According to the present invention, a catalyst body is composed of a base material and a catalyst coating layer formed on the surface of the base material and comprising at least activated alumina, zeolite, a platinum group metal and an inorganic binder. Is characterized by.

The present invention is also characterized by the addition of an alkaline earth metal. Furthermore, the present invention is characterized in that the catalyst coating layer is formed by adjusting the median particle diameter of the particles in the slurry of the catalyst material to 1 μm or more and 9 μm or less.

[0007]

According to the present invention, indoor odorous components are usually adsorbed and deodorized by zeolite and activated alumina in the catalyst coating layer. Next, the zeolite and activated alumina, before adsorbing the odorous components up to its adsorption capacity limit, by heating the catalyst body of the present invention by a heating means such as a heating element or warm air, the catalyst substance in the catalyst coating layer ( The platinum group metal) is activated to oxidize and decompose the odor components adsorbed on the zeolite and alumina in the catalyst coating layer and the odor components near the catalyst body by the catalytic action of the activated catalyst substance coexisting with the zeolite and alumina. And make it an odorless component. Since the adsorbed odorous components are removed from the zeolite and alumina heated by the heating means, the adsorption ability is restored again, and after the heating by the heating means is stopped, the odorous components can be adsorbed again. In this way, the adsorption of odorous components by zeolite and alumina when not heated, the heating regeneration of zeolite and alumina when heated, and the catalytic decomposition of odorous components are repeated alternately, so that the catalyst surroundings It is possible to continuously remove the malodor without raising the temperature so much.

Further, it is desirable that the catalyst coating layer contains alumina containing an alkaline earth metal, and by using the alumina containing an alkaline earth metal together, the adsorption characteristic of an acidic odor substance can be improved. it can.

Further, according to the present invention, since the median particle diameter of the particles in the mixed slurry is 1 μm or more and 9 μm or less, it is possible to obtain a catalyst coating layer having appropriate hardness and being hard to crack.

[0010]

EXAMPLES As the base material used in the catalyst body of the present invention, various materials such as metals, ceramics and glass can be used. As the shape of the base material, various shapes such as a plate shape, a honeycomb shape, a porous body, a rod shape, and a tubular shape can be used.

Of these, alumina, mullite, silica-alumina-titania, cordierite, silica glass, lithium silica
A metal body having a glass cover and a glass coating layer has good adhesion between the catalyst coating layer and the substrate, and silica glass is particularly preferable.

Further, it is preferable that the base material is a heating element and the above-mentioned glass body, ceramic body, or metal body having a glass coating layer that contains the heating element or is in contact with the heating element.
This efficiently heats the platinum group metal in the catalyst coating layer,
This is because it can be activated promptly.

The activated alumina of the present invention comprises β-, γ-, δ
Metastable alumina such as −, θ−, η−, ρ−, χ− alumina. Further, by supporting a promoter such as a rare earth oxide on the surface of alumina, the activity can be further improved. Further, it is desirable to add barium to the activated alumina because the thermal stability of the alumina can be improved.

The content of activated alumina in the catalyst coating layer of the present invention is preferably 20 to 60% by weight. When the content of activated alumina is less than 20 wt%, it is difficult to obtain sufficient adhesion of the catalyst coating layer to the quartz glass tube, and when it exceeds 80 wt%, the odor adsorption capacity of the catalyst coating layer decreases.

As the zeolite of the present invention, various zeolites can be used. Among them, copper ion-exchanged zeolite is particularly preferable because it has the best odor adsorption capacity.

As the inorganic binder of the present invention, silica, alumina, bentonite, Li silicate, water glass and the like can be used. Among them, silica is the most desirable from the viewpoint of adhesion, and an aqueous solution of silicic acid anhydride is preferable as a silica raw material. By including silica in the catalyst coating layer, the adhesion of the catalyst coating layer to the quartz tube can be maximized.

The desirable content of silica is 10 to 40 wt% in the catalyst coating layer. When the content of silica exceeds 40 wt%, the catalyst coating layer is likely to be cracked and the adhesiveness is apt to be deteriorated. On the other hand, if it is less than 10% by weight, sufficient effect of improving adhesion property of silica cannot be obtained.

The silica of the present invention is silicon dioxide, but silicic acid may be used instead.

It is desirable that the catalyst coating layer of the present invention contains alumina containing an alkaline earth metal. By using together with alumina containing alkaline earth metal,
It is possible to improve the adsorption characteristics of acidic odorous substances.
A desirable content of alumina containing an alkaline earth metal is 5 to 30 wt%. If it is less than 5%, the effect of improving the acidic odor adsorption property of the catalyst coating layer cannot be sufficiently obtained, and if it exceeds 30 wt%, the adhesion of the catalyst coating layer is deteriorated.

Alkaline earth metals used for alumina containing alkaline earth metals include magnesium, calcium, strontium and barium. The alkaline earth metal-containing carbonate, nitrate, hydroxide or oxide may be reacted with alumina or aluminum hydroxide at a high temperature to obtain alumina containing the alkaline earth metal.

In the present invention, a catalyst catalyst layer containing at least activated alumina, zeolite and a platinum group metal is formed on the surface of a base material. By using activated alumina, zeolite and platinum group metal at the same time, it is possible to obtain a synergistic effect of improving the adsorption property for acidic odor components as compared with the case of using activated alumina or zeolite alone.

The platinum group metal of the present invention is preferably Pt or Pd, and more preferably both Pt and Pd. This is because the oxidative decomposition power of Pt and Pd is higher than that of Rh and Ir, and the higher activity is obtained by using both Pt and Pd. further,
When Ru is used, Ru is volatilized and becomes a harmful substance when used at high temperature. Various methods can be used as a method of incorporating the platinum group metal into the alumina. For example, it can be prepared by dipping alumina in an aqueous solution of the platinum group metal salt, followed by drying and firing. Further, it is desirable that the platinum group metal is contained in the activated alumina in advance. This is because the catalytic oxidative decomposition property can be improved.

In order to obtain a synergistic effect of improving the adsorption characteristics for the above acidic odorous components, the desirable platinum group metal content is preferably 0.1 to 8 wt% in the catalyst coating layer. This has a platinum group metal content of 0.1
When it is less than wt%, the above-mentioned synergistic effect cannot be obtained sufficiently, and when it exceeds 8 wt%, the synergistic effect decreases.

The catalyst coating layer has a two-layer structure of a catalyst layer comprising at least activated alumina, zeolite and a platinum group metal and a protective coating layer formed on the surface of the catalyst layer and comprising at least one selected from alumina and silica. Is desirable.

On the outer surface of the catalyst layer, alumina and / or
Alternatively, by providing a coating layer made of silica, the film strength can be improved without deteriorating the activity of the catalyst.

It is desirable that the catalyst coating layer contains cerium oxide. By including cerium oxide in the catalyst coating layer, the catalytic oxidative decomposition activity for hydrocarbon compounds can be improved.

The desirable content of cerium oxide is preferably 2 to 15 wt% in the catalyst coating layer. When the content of cerium oxide exceeds 15 wt%, the oxidative decomposition characteristics of the catalyst begin to deteriorate, and when it is less than 2 wt%, a sufficient addition effect of cerium oxide cannot be obtained.

It is desirable that the catalyst coating layer of the present invention contains titanium oxide. By including titanium oxide in the catalyst coating layer, the catalytic oxidation activity for nitrogen compounds such as ammonia can be improved.

The content of titanium oxide is 3 to 3 in the catalyst coating layer.
It is preferably 15 wt%. If the content of titanium oxide exceeds 15 wt%, the adhesion property of the catalyst coating layer will deteriorate, and if it is less than 3 wt%, a sufficient effect of adding titanium oxide cannot be obtained.

The specific surface area of the catalyst coating layer is preferably 10 m ² / g or more. This is because, as the specific surface area of the catalyst coating layer increases, the ratio of far infrared radiation amount to the amount of near infrared radiation emitted increases, but the specific surface area is 10 m.
^This is because a sufficient far infrared radiation ratio can be obtained at ² / g or more.

When forming the catalyst coating layer, it is desirable to roughen the surface of the quartz tube and then provide the catalyst coating layer, or to sufficiently degrease the surface of the quartz tube and then provide the catalyst coating layer. By this manufacturing method, the adhesion between the catalyst body and the catalyst coating layer can be improved.

Various methods can be used for forming the catalyst coating layer. For example, spray coating, dip coating,
There are electrostatic coating, roll coat method, screen printing method and the like.

The median particle diameter of the particles in the mixed slurry is 1 μm.
It is desirable that it is not less than m and not more than 9 μm. When it exceeds 9 μm, the coating layer becomes soft, and when it is finer than 1 μm, the coating layer tends to crack.

It is also desirable to include aluminum nitrate in the mixed slurry. This is because the addition of aluminum nitrate improves the adhesion of the resulting catalyst coating layer.

Specific examples of the present invention will be described below. (Example 1) 400 g of γ-alumina and an inorganic binder
As aluminum hydroxide 100 g, copper ion exchange type zeolite 500 g, water 1500 g, chloroplatinic acid as P
Slurry A was prepared by adding 30 g as t, 15 g as palladium chloride as Pd, and an appropriate amount of hydrochloric acid, and thoroughly mixing using a ball mill. The outside diameter of this slurry-A is 1
After coating the surface of a quartz tube having a diameter of 0 mm, an inner diameter of 9 mm and a length of 15 cm by a spray method, the quartz tube was dried at 100 ° C. for 2 hours and then baked at 500 ° C. for 1 hour to thermally decompose aluminum hydroxide and a platinum group metal salt. Then, a catalyst coating layer containing alumina and a platinum group catalyst was formed. Using this quartz tube, a nichrome wire as an electric resistor, and an insulator, a catalyst body A containing the heating element of the present invention was prepared. The amount of catalyst coating layer is
It was 0.2 g. The structure of a catalyst device using the catalyst body A is shown in FIG.

In FIG. 1, the catalyst body A of the present invention is 100
It is composed of a nichrome wire 1 having a V voltage of 300 W, a quartz tube 2 and the catalyst coating layer 3 formed on the surface thereof, and is insulated and held by an insulator 4.

When the nichrome wire 1 is not energized, the odorous components in the room are usually adsorbed and deodorized by the zeolite and activated alumina in the catalyst coating layer 3. When the nichrome wire 1 is energized before the odor component is adsorbed to the limit of the odor adsorption capacity of the catalyst coating layer 3, the nichrome wire 1 emits heat rays in the entire circumferential direction. At this time, since the catalyst coating layer 3 is installed so as to cover the outer periphery of the quartz tube 2, heat rays radiated from the nichrome wire 1 in the entire circumferential direction are radiated to the catalyst coating layer 3.
Radiant heating of the catalyst coating layer 3 is efficiently performed, the catalyst is heated to its activation temperature in a short time, and the temperature of the catalyst coating layer can be increased. The odorous components adsorbed on the catalyst coating layer 3 are oxidized and purified by the activated catalyst.

Further, since the catalyst body A also heats the air in the vicinity of the catalyst body A, the air flow 5 is generated as convection in the vicinity of the catalyst body A. When the air stream 5 comes into contact with the catalyst coating layer heated to the activation temperature by heating from the nichrome wire 1 or diffuses into the coating layer, odors and harmful components contained in the air stream 5, for example, Carbon monoxide (hereinafter referred to as CO)
And ammonia are catalytically purified.

Therefore, even if an odor, cigarette smoke, or harmful gas such as CO drifts in the atmosphere in which the catalyst A is placed, it can be purified during heating or use, and a comfortable environment can be created.

Next, 445 g of .gamma.-alumina containing platinum and palladium in the same amount as Slurry A in advance using chloroplatinic acid and palladium chloride, 100 g of aluminum hydroxide as an inorganic binder, and a copper ion exchange type zeolite.
Slurry A ′ was prepared by thoroughly mixing 500 g and 1500 g of water using a ball mill. This slurry
A'was applied on the surface of a quartz tube having an outer diameter of 10 mm, an inner diameter of 9 mm and a length of 15 cm by a spray method, dried at 100 ° C for 2 hours, and then calcined at 500 ° C for 1 hour to obtain an alumina and platinum group catalyst. A catalyst coating layer containing was formed. Using this quartz tube, a nichrome wire as an electric resistor, and an insulator, a catalyst body A ′ containing the heating element of the present invention was prepared.
The amount of the catalyst coating layer was 0.2 g, which was the same as that of the catalyst A.

A mercaptan oxidation purification test was carried out on the catalyst bodies A and A ′, and comparison was made with the catalyst body having no catalyst coating layer. In the acetic acid oxidation purification test, the catalyst body was placed in a 0.1 m ³ cubic container made of fluorine resin and heated to 450 ° C. on the outer surface of the center of the catalyst body. It was carried out by injecting mercaptan into a container so that the concentration of the mercaptan was changed and examining the change with time of the concentration.
The change with time of the mercaptan concentration was examined by gas chromatography. The results are shown in (Table 1).

As is clear from Table 1, the catalyst body A '
Has a higher activity than that of the catalyst body A, and the oxidative decomposition performance of the odorous component can be improved by including platinum group metal in the activated alumina in advance.

[0043]

[Table 1]

(Example 2) Catalyst body A prepared in Example 1
In the catalyst coating layer 0, the content of γ-alumina was set to various contents between 10 wt% and 85 wt% with respect to all the solid components in the catalyst coating layer, and the active alumina increment was reduced by the amount of copper zeolite. A catalyst body having 0.2 g was prepared. A thermal shock test was performed on these catalyst bodies to examine the adhesion of the coating layer. In the thermal shock test, the electric resistance built in the quartz tube is energized, the temperature of the catalyst coating layer is set at every 25 ° C., the temperature is maintained for 10 minutes, and then the temperature is dropped in room temperature water to remove the peeling of the coating layer. The presence or absence was checked and the maximum temperature at which peeling did not occur was defined as the thermal shock resistance temperature.

The ability of each catalyst to adsorb odorous substances when the nichrome wire was not energized was tested using methyl mercaptan, which is a typical odorant. The test method was as follows. The above various catalysts were placed in a closed box of 0.1 m ³ in volume whose inner wall surface was coated with fluorine resin, and the air was diluted to 10 pp in the box.
Methyl mercaptan at a concentration of m was adsorbed, and the amount of residual methyl mercaptan was measured 30 minutes after the catalyst was added and the amount was determined as the methyl mercaptan adsorption capacity. The air in the box was stirred by the fan during the experiment. The results are shown in (Table 2).

As is clear from Table 2, when the content of activated alumina is less than 20 wt%, the thermal shock resistance temperature is lowered, and when it exceeds 80 wt%, the residual mercaptan concentration is high and the odor substance adsorption ability is lowered. Therefore, when the content of activated alumina is 20 wt% or more and 80 wt% or less, the best adhesion (heat shock resistance) and odor substance adsorption ability are obtained, which is desirable.

[0047]

[Table 2]

(Example 3) Catalyst body A prepared in Example 1
In, a catalyst body was prepared by replacing the copper zeolite in the catalyst coating layer with another ion exchange zeolite. With respect to these catalyst bodies, the odor substance adsorption capacity of each catalyst body when the nichrome wire was not energized (room temperature) was tested using methyl mercaptan, which is a typical odor substance. The test method is Example 2
The same method was used. The results are shown in (Table 3).

As is clear from (Table 3), copper ion-exchanged zeolite is the most preferable because it has the ability to adsorb odorous substances.

[0050]

[Table 3]

(Example 4) In the slurry A prepared in Example 1, the aluminum hydroxide in the slurry was replaced with various inorganic binders so that the amount of the inorganic binder contained in the final solid content was the same. A slurry was prepared to prepare a catalyst body similar to that of Example 1. In order to investigate the film hardness of these catalyst coating layers, JISG-3
A pencil hardness test of 320 was performed. Further, a methyl mercaptan purification test was performed on each of the catalyst bodies in the same manner as in Example 2. The test method was as follows. The above various catalysts were placed in a closed box of 0.1 m ³ in volume whose inner wall surface was coated with fluorine resin to generate heat by energizing the electric resistance of the catalyst, and the air diluted in the box was 10 ppm. Methyl mercaptan having a concentration of was oxidatively decomposed, and the residual rate was measured 10 minutes after the catalyst was added. The results are shown in (Table 4). The air in the box was agitated by a fan during the experiment.

As shown in (Table 4), when alumina sol or bentonite was used, the film hardness was lowered, and when Li silicate or water glass was used, the film hardness was improved, but the film was not porous and the catalytic activity was lowered. .. As described above, it is most desirable to use silica as the inorganic binder,
A strong coating can be formed without lowering the catalytic activity.

[0053]

[Table 4]

Example 5 The slurry prepared in Example 1
In A, colloidal silica was used as the inorganic binder instead of aluminum hydroxide, and various contents of 0 wt% to 50 wt% were calculated by converting the colloidal silica into silica with respect to all solid components in the slurry. In the same manner as in Example A, a slurry was prepared by preparing a slurry in which the amount of increased silica was reduced in the amount of γ-alumina, and a catalyst coating layer of 0.2 g of the present invention was formed on the outer circumference of the quartz tube. It was created. A thermal shock test was performed on these catalyst bodies to examine the adhesion of the coating layer. The thermal shock test was performed in the same manner as in Example 2. The results are shown in (Table 5).

As is clear from Table 5, a silica content of 10 wt% or more and 40 wt% or less is desirable because the best adhesion (heat shock resistance) can be obtained.

[0056]

[Table 5]

(Example 6) In the catalyst body A of Example 1, the catalyst bodies using various tubular base materials shown in (Table 6) were prepared.
This catalyst was prepared in the same manner as in Example 1, and a thermal shock test was conducted on this catalyst to examine the adhesion of the coating layer. The thermal shock test was performed in the same manner as in Example 2. The results are shown in (Table 6).

As is clear from (Table 6), alumina,
Mullite, silica-alumina-titania, cordierite or silica glass, lithium silicate glass, and a metal body having a glass coating layer are desirable because the adhesion between the catalyst coating layer and the substrate is good, and silica glass is particularly preferable.

[0059]

[Table 6]

(Example 7) At the time of preparing the slurry-A of Example 1, the milling time in the ball mill was changed to prepare various slurries having a central particle diameter of 0.8 µm to 15 µm.

Using these slurries, a catalyst body having 0.2 g of a catalyst coating layer on the outer peripheral surface of a quartz tube which had been degreased and washed was prepared in the same manner as in Example 1.

Next, the film hardness of the coating layer formed here is J
A pencil hardness test of ISG-3320 was performed. The results are shown in (Table 7).

[0063]

[Table 7]

As is clear from (Table 7), if the thickness exceeds 9 μm, the coating layer becomes soft, and if it is thinner than 1 μm, the coating layer tends to crack.

Therefore, the median particle diameter of the particles in the mixed slurry is preferably 1 μm or more and 9 μm or less.

(Embodiment 8) Outer diameter 10 mm, inner diameter 9 mm,
The outer peripheral surface of the quartz tube having a length of 344 mm was degreased and washed.

On the other hand, in the same manner as in the slurry A'of Example 1, chloroplatinic acid and palladium chloride were used in advance to prepare slurry A.
Γ-alumina 4 containing the same amount of platinum and palladium as
45 g and aluminum hydroxide 1 as an inorganic binder
00 g, copper ion-exchange type zeolite 400 g, and alumina 100 g containing 5 wt% of barium, water 15
Slurry C was prepared by thoroughly mixing 00 g with a ball mill.

The average particle size of this slurry C is 4.
It was 5 μm. This slurry C was spray-coated on the entire circumference, leaving 33 mm on both sides of the outer peripheral surface of the quartz tube, dried at 100 ° C. for 2 hours, and then calcined at 500 ° C. for 1 hour to react silicic acid. Then, a quartz tube having a catalyst coating layer was prepared. The coating weight is 1.0 g.

The barium-containing alumina was prepared by reacting a predetermined amount of barium carbonate with aluminum hydroxide at 1000 ° C.

A 40 Ω coil-shaped nichrome wire 1 was built in this quartz tube, and a catalyst body C having a catalyst coating layer which was insulated and held on both sides of the quartz tube by an insulator 4 was prepared.

Further, the slurry A'of Example 1 was applied to the entire circumference of the quartz tube by a spray method except for 33 mm on both sides of the outer peripheral surface, followed by drying at 100 ° C. for 2 hours, followed by 5
It was calcined at 00 ° C. for 1 hour to react with silicic acid to prepare a quartz tube having a catalyst coating layer. The coating weight is 1.0 g.
A 40 Ω coil-shaped nichrome wire 1 was built in this quartz tube, and an insulator 4 was used to insulate and hold both sides of the quartz tube to form a catalyst body A′2 having a catalyst coating layer.

Next, an acetic acid adsorption test was conducted on the catalyst bodies C and A'2, and comparison was made with the catalyst bodies having no catalyst coating layer. In the acetic acid adsorption test, the catalyst body was placed in a cubic Fluorocarbon resin container of 0.25 m ³ , and the catalyst body was not heated and acetic acid was injected into the container so that the concentration became 40 ppm. It went by investigating. The change with time of the acetic acid concentration was examined by gas chromatography.

The results are shown in (Table 8). As is clear from (Table 8), the catalyst bodies A′2, C having the catalyst coating layer formed thereon
Can be deodorized by acetic acid adsorption at room temperature. Further, the catalyst body C was superior to the catalyst body A′2 in the acetic acid adsorption property.
Therefore, it is desirable that the catalyst coating layer contains alumina containing an alkaline earth metal. By using alumina containing an alkaline earth metal together, it is possible to improve the adsorption characteristics of acidic odor substances.

[0074]

[Table 8]

Example 9 In the slurry A of Example 1, a comparative slurry 1 containing no platinum group salt, a comparative slurry containing no platinum group salt and γ-alumina containing copper ion-exchanged zeolite were used. 2 and a comparative slurry 3 containing no platinum group salt and containing γ-alumina as the copper ion exchange type zeolite, each having a catalyst coating layer of 1.0 g similar to that of the catalyst body C. Media 1, 2 and 3 were created.

Comparative catalyst bodies 1, 2, and 3 were subjected to the acetic acid adsorption test of Example 8, and the acetic acid residual ratio 60 minutes after the start of measurement was compared with that of catalyst body A2 of the invention.

The results are shown in (Table 9). As is clear from (Table 9), the catalyst body A2 of the present invention was superior to the comparative catalyst bodies 1, 2 and 3 in the adsorption property of acetic acid which is an acidic odor component. Therefore, by using activated alumina, zeolite, and platinum group metal at the same time, it is possible to obtain a synergistic effect of improving the adsorption property for acidic odorous components as compared with the case of using activated alumina or zeolite alone.

[0078]

[Table 9]

Further, in the slurry A of Example 1, all the platinum group metal salts were chloroplatinic acid, and a slurry containing 0 to 10 wt% of Pt in the solid content of the slurry was prepared. Each of the catalyst coating layers similar to 1.
A catalyst body having 0 g was prepared.

The acetic acid adsorption test of Example 8 was conducted on these catalysts, and the residual acetic acid ratios 60 minutes after the start of measurement were compared.

The results are shown in (Table 10). As is clear from (Table 10), the platinum group metal content is 0.1 wt.
If it is less than 8% by weight, the above-mentioned synergistic effect cannot be sufficiently obtained, and if it exceeds 8 wt%, the synergistic effect is lowered.

Therefore, in order to obtain the synergistic effect of improving the adsorption property for the acidic odorous component, the platinum group metal content is preferably 0.1 to 8 wt% in the catalyst coating layer.

[0083]

[Table 10]

(Embodiment 10) Outer diameter 10 mm, inner diameter 9 m
The outer peripheral surface of the quartz tube having a length of m and a length of 344 mm was degreased and washed.

On the other hand, γ-alumina 140 containing Pt
g, 400 g of a silicic acid anhydride colloid aqueous solution containing 20 wt% in terms of silicic acid anhydride, 200 g of water and copper ion exchange A
Slurry D was prepared by thoroughly mixing 140 g of type zeolite, 38 g of γ-alumina, and 3 g of barium carbonate with a ball mill. The average particle size of this slurry D was 4.5 μm. The slurry D was spray-coated on the entire circumference of the quartz tube, leaving 33 mm on both sides of the outer peripheral surface, dried at 100 ° C. for 2 hours, and then calcined at 500 ° C. for 1 hour to react with silicic acid. Then, a quartz tube having a catalyst coating layer was prepared. The coating weight is 1.0 g, and the Pt content is
It is 25 mg.

A 40 Ω coil-shaped nichrome wire 1 was built in this quartz tube, and an insulator 4 was used to insulate and hold both sides of the quartz tube to prepare a catalyst body C having a catalyst coating layer.

An acetic acid adsorption test similar to that in Example 8 was conducted on this catalyst body D and compared with the catalyst body C. The results (Table 1
It is shown in 1).

As is clear from Table 11, the catalyst body C using the barium-containing alumina was superior to the catalyst body D containing the same amount of barium as a carbonate in the acetic acid adsorption property.

[0089]

[Table 11]

(Example 11) In the slurry C prepared in Example 8, a slurry was prepared in which the alkaline earth metal contained in the alumina in the slurry was variously changed as shown in (Table 8). A catalyst similar to that of No. 8 was prepared.

With respect to these catalyst bodies, the ability of each catalyst body to absorb an odor substance at room temperature was tested using acetic acid. The test method was the same as in Example 8. The results (Table 1
2).

As is clear from (Table 12), when barium is used among the alkaline earth metals used by being contained in alumina, the time until the acetic acid residual rate reaches 50% depends on other alkaline earth metals. Since barium is the shortest, barium has the best odor substance adsorption capacity and is desirable.

[0093]

[Table 12]

(Example 12) In the slurry C prepared in Example 8, various contents of alumina containing an alkaline earth metal were set to 0 to 40 wt% with respect to the total solid content in the slurry, A slurry in which the amount of increase in alumina was reduced from zeolite was prepared, and using this, a catalyst body was prepared in the same manner as in Example 8 in which 1.0 g of the catalyst coating layer was formed on the entire outer peripheral surface of the quartz tube.

For these catalysts, the ability of each catalyst to adsorb odorous substances at room temperature was tested using acetic acid. The test method was the same as in Example 8. At the same time, the same thermal shock test as in Example 2 was performed. The results are shown in (Table 13).

As is clear from (Table 13), when the content of alumina is less than 5 wt%, a sufficient addition effect on acetic acid adsorption cannot be obtained, and the content of alumina is 3%.
If it is more than 0 wt%, the adhesion of the catalyst coating layer will decrease.

Therefore, the desirable content of alumina containing an alkaline earth metal is 5 wt% or more and 30 wt% or less.

[0098]

[Table 13]

Example 13 In the catalyst body A prepared in Example 1, the platinum group metal was replaced by Pd or Ru, Rh, I.
The oxidative decomposing power of acetaldehyde was examined for the case where r was changed and the case where Pt and Pd were mixed at a ratio of 2: 1 (catalyst A). The amount of the catalyst coating layer was 1 g, and the total amount of the platinum group metals was the same in 0.2 g of the catalyst coating layer. The acetaldehyde oxidation purification test
Place the catalyst in a 0.1 m ³ cubic container made of fluorine resin, and heat it so that the temperature of the outer surface of the center of the catalyst is 450 ° C., and then add acetaldehyde to a concentration of 100 ppm in the container. It was carried out by injecting into the column and examining the change over time in concentration. The residual rate of acetaldehyde 10 minutes after the start of the experiment is shown in (Table 14).

As shown in (Table 14), Pt, Pd, R
u had a higher activity than Rh and Ir, and it became even higher by using both Pt and Pd. Next, when the activity of each of the catalysts that had been heat-treated at 850 ° C. for 50 hours was examined, only Ru had a significantly deteriorated activity, and the activity of the other catalysts did not change much.
This is considered to be the result of Ru volatilization at high temperature. From the above results, it is desirable to use thermally stable Pt and Pd.

[0101]

[Table 14]

Example 14 In the catalyst body of the present invention,
A catalyst in which a coating layer having a two-layer structure is formed on the surface of a base material, a catalyst layer comprising at least active alumina, zeolite, and a platinum group metal, and a protective coating layer formed on the surface of the catalyst layer, the protective coating layer comprising at least one selected from alumina and silica. The device is shown in FIG. In FIG. 2, 6 is a nichrome wire, 7 is a quartz tube, 8 is a catalyst coating layer, 9 is an overcoat layer, 10 is an insulator, and 11 is an air flow.

Outer diameter 10 mm, inner diameter 9 mm, length 344 m
The outer peripheral surface of the quartz tube of m was degreased and washed. On the other hand, the specific surface area 21
60 g of 0 m ² / g aluminum hydroxide and 20% by weight of silicic acid anhydride in a silicic acid anhydride colloidal solution 80
0 g, 320 g of copper ion-exchanged A-type zeolite, and water 7
A slurry was prepared by adding 00 g and 36 g of chloroplatinic acid as Pt and thoroughly mixing them using a ball mill. The average particle size of this slurry was 3 μm. This slurry was spray-coated on the entire circumference, leaving 33 mm on both sides of the outer peripheral surface of the quartz tube, dried at 100 ° C. for 2 hours, and then calcined at 500 ° C. for 1 hour to obtain silica and hydroxide. By reacting aluminum, a quartz tube having a copper ion-exchanged zeolite and a silica-alumina catalyst coating layer was prepared.
The carrying amount of the coating layer is 0.60 g, and the Pt content is 15.5.
mg. When the strength of this film was measured by the pencil hardness test method, it was 4B.

Cover both ends 33 mm of this quartz tube,
After impregnating with 10 wt% alumina sol and drying at room temperature,
By firing at 500 ° C. for 1 hour, 0.12 g of an alumina overcoat layer was supported. When the strength of this film was measured by the pencil hardness test method, it was B. Further, instead of alumina sol, silica sol or a mixture of alumina sol and silica sol was used to form the same silica protective coating layer and silica-alumina protective coating layer, and the pencil hardness of the catalyst coating layer was good at HB and B, respectively.

(Example 15) At the time of preparing the slurry A of Example 1, after forming an alumina-zeolite coating layer on a quartz tube without containing a platinum group metal salt, an aqueous platinum group metal salt solution was prepared by a dip method. After impregnation, heat treatment was performed to prepare a catalyst body B carrying the platinum group catalyst in the same amount as the catalyst body A.

Ammonia was selected as an odor substance for these catalysts, and this ammonia purification test was conducted.

The test method was as follows: The catalyst body was placed in a closed box of 0.1 m ³ in volume whose inner wall surface was coated with the same fluorocarbon resin as in Example 2, and the air-diluted ammonia in the box at a concentration of 10 ppm was added to the catalyst body. The electric resistor was oxidatively decomposed by applying a voltage of 100 V, and the energization time required until 80% of the ammonia in the box was oxidatively decomposed was measured.

The results are as follows: catalyst body A for 31 minutes, catalyst body B for 3 minutes
It was 8 minutes. Therefore, the catalyst body A prepared by using the slurry A containing the platinum group metal salt in the slurry has a shorter odor substance in a shorter time than the catalyst body obtained by the method for preparing the catalyst body B. Is desirable because it can oxidatively decompose and obtain better catalytic properties.

(Example 16) Further, the slurry in Example 1
Γ-alumina and aluminum hydroxide were used in A, but the total amount was the same, and a slurry prepared by mixing these in various proportions was used.
Was prepared, and a catalyst body was prepared using these slurries in the same manner as in the example. The prepared catalyst body was subjected to the thermal shock test shown in Example 2 and the ammonia purification test shown in Example 6. The results are shown in (Table 15).

As is clear from (Table 15), Example 1
By substituting activated alumina for aluminum hydroxide in the slurry A, it is possible to improve the catalytic properties. Among these, when the amount of aluminum hydroxide substituted with activated alumina exceeds 94 wt%, the thermal shock resistance decreases,
On the other hand, if it is less than 23% by weight, the effect of substitution with activated alumina cannot be sufficiently obtained. Therefore, the desirable substitution amount of aluminum hydroxide for activated alumina is from 23 wt% to 94 wt%.
Is.

[0111]

[Table 15]

Example 17 The slurry A of Example 1 was prepared as follows.
Various amounts of cerium nitrate hexahydrate were added, and the same procedure as in Example 1 was used to obtain the same amount of the catalyst coating layer as the catalyst A on the surface of the quartz tube. The amounts formed different catalyst bodies as in (Table 16). The increase in cerium oxide in the catalyst coating layer is
It was prepared by reducing the amount of alumina.

For these catalysts, acetic acid was selected as the odor substance, and this acetic acid purification test was conducted in the same manner as in Example 7.

The test method was as follows: The catalyst body was placed in a closed box of 0.1 m ³ in volume whose inner wall surface was coated with the same fluorine resin as in Example 2, and the acetic acid at a concentration of 50 ppm diluted with air in the box was added to the catalyst body. Was subjected to oxidative decomposition by applying a voltage of 100 V to the sample, and the energization time required until 80% of acetic acid in the box was oxidatively decomposed was measured.

The results are shown in (Table 16). As shown in (Table 16), by including cerium oxide in the catalyst coating layer, the catalytic oxidation activity for hydrocarbon compounds can be improved.

When the content of cerium oxide exceeds 15% by weight, the oxidative decomposition characteristics of the catalyst begin to deteriorate, and when it is less than 2% by weight, a sufficient addition effect of cerium oxide cannot be obtained. Therefore, the desirable content of cerium oxide is 2 in catalyst coating
~ 15 wt%.

[0117]

[Table 16]

(Embodiment 18) The slurry A of Embodiment 1 is
Titanium oxide was added in various quantitative ratios, and the same amount of the catalyst coating layer as that of the catalyst A on the surface of the quartz tube was used in the same manner as in Example 1, and the titanium oxide content in the catalyst coating layer was Different catalyst bodies were formed as in 17). The increase in titanium oxide in the catalyst coating layer was prepared by reducing the amount of alumina.

Ammonia was selected as an odor substance for these catalysts, and this ammonia purification test was carried out in Example 6.
I went the same way. The adhesion test was performed in the same manner as in Example 2.

The results are shown in (Table 17). As shown in (Table 17), by including titanium oxide in the catalyst coating layer,
The catalytic oxidation activity for ammonia can be improved.

When the content of titanium oxide exceeds 15 wt%, the adhesion property of the catalyst coating layer begins to deteriorate, and when it is less than 3 wt%, a sufficient effect of adding titanium oxide cannot be obtained. 3 to 3 in the catalyst coating layer
It is 15 wt%.

[0122]

[Table 17]

Example 19 The cordierite plate-like, honeycomb-like, as shown in (Table 18),
A catalyst coating layer was formed using the slurry A of Example 1 on a porous body, rod-shaped or tubular substrate. Next, the adhesion test was performed on the catalyst coating layer formed on the substrate. The results are shown in (Table 17).

As is clear from (Table 18), the base material shape is preferably honeycomb, porous or tubular base material, and the tubular body is particularly preferable because it has the best thermal shock resistance.

[0125]

[Table 18]

[0126]

INDUSTRIAL APPLICABILITY As described above, in the present invention, harmful gases such as odors in the atmosphere in which the catalyst is placed and cigarette smoke are removed by the adsorption action and the catalytic action of the catalyst coating layer,
Purified. Therefore, by installing a catalyst body,
It is possible to provide a comfortable environment with little odor substance. In particular, the deodorizing effect is improved by adding an alkaline earth metal.

Further, according to the present invention, the catalyst coating layer having a hardness which is hard to be cracked and is easy to handle is formed by adjusting the center particle diameter of the particles in the slurry of the catalyst material to 1 μm or more and 9 μm or less.

[Brief description of drawings]

FIG. 1 is a sectional view of a catalyst device in which a catalyst body according to an embodiment of the present invention is formed.

FIG. 2 is a sectional view of a catalyst device having a catalyst body according to another embodiment of the present invention.

[Explanation of symbols]

 1 Nichrome wire 2 Quartz tube 3 Catalyst coating layer 4 Insulator 5 Air flow 6 Nichrome wire 7 Quartz tube 8 Catalyst coating layer 9 Insulator 10 Air flow 11 Protective coating layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kyoe Yamade 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] 1. A catalyst body comprising a base material and a catalyst coating layer formed on the surface of the base material and comprising at least activated alumina, zeolite, a platinum group metal and an inorganic binder. 2. The catalyst body according to claim 1, wherein the zeolite is a copper-containing zeolite. 3. The catalyst body according to claim 1, wherein the inorganic binder is silica. 4. The catalyst body according to claim 1, wherein the catalyst coating layer contains alumina containing an alkaline earth metal. 5. The catalyst body according to claim 7, wherein the alkaline earth metal is barium. 6. A coating having a two-layer structure comprising a catalyst layer comprising at least activated alumina, zeolite and a platinum group metal on the surface of a substrate and a protective coating layer comprising at least one selected from alumina and silica formed on the surface of the catalyst layer. A catalyst body formed by forming a layer. 7. A mixed slurry containing at least activated alumina or aluminum hydroxide, zeolite, and a platinum group metal salt and having a median particle diameter of the particles in the slurry of 1 μm or more and 9 μm or less is applied to the surface of the base material. And then drying and firing to form a catalyst coating layer.