JPH06154616A - Production of catalytic body - Google Patents

Abstract

PURPOSE:To form a catalytic body for removal of a foul odor and noxious gas while easily and uniformly dispersing the constituent components. CONSTITUTION:At least one among a water-soluble di- or higher valent metallic salt, a substance exhibiting acidity when dissolved in water, a substance exhibiting basicity when dissolved in water and a surfactant is added to a sol prepd. by mixing a silica sol with a salt of a Pt group metal or a metal oxide with a carried Pt group metal and zeolite or magnesium silicate. They are made to gel, molded and fired to produce the objective catalytic body used for removal of a foul odor and noxious gas. By this method, the constituent components in the catalytic body can easily and uniformly mixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for heating, hot water supply, drying, cooking, refrigerating, air conditioning equipment and the like, and has a function of removing odorous components existing in the room, toilet, refrigerator, cooker and the like. The present invention relates to a method for manufacturing a medium.

[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. These malodorous substances are mainly ammonia, fatty acids, unsaturated hydrocarbons, sulfur-containing organic compounds, nitrogen-containing organic compounds, etc., which are generated by the physiological actions of humans such as sweat and the decomposition of foods. is there.

However, the conventional adsorption by activated carbon has a problem in that the adsorption capacity varies depending on the odorous component species, and the adsorption must be replaced when the saturated adsorption is reached. 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.

Therefore, in order to solve the above-mentioned problems of the prior art, there has been proposed a deodorizing device provided with a catalyst body composed of a noble metal and zeolite or magnesium silicate and an inorganic binder, and a heating source for regeneration. As a result, various odorous components in the room can be absorbed and deodorized without variation and can be used semipermanently.

This is because the heating source is intermittently energized, and when not heated, zeolite or magnesium silicate contained in the catalyst adsorbs a malodorous component to deodorize,
When the adsorption capacity reaches saturation, the catalytic body is heated to activate the noble metal that is the catalytic material, and the odorous substances in the air in contact with the catalytic body are deodorized by oxidative decomposition and at the same time converted into zeolite or magnesium silicate. In this method, the adsorbed odor substance is oxidatively decomposed to regenerate the adsorption ability of zeolite or magnesium silicate, and then deodorized at room temperature again.

[0006]

In the method of repeating adsorption and oxidative decomposition, a method of coating a catalyst film on the outer surface of a heating element such as a quartz tube heater, and a method of forming a granular or pellet shape or a honeycomb shape are used. There is a method of placing a heating element near the catalyst body.

Among them, in order to use a granular catalyst body, sintering obtained by firing a sol obtained by mixing a platinum group salt or a metal oxide carrying a platinum group catalyst, zeolite or magnesium silicate, and silica sol. There is a method in which the body is crushed and sieved to select one having a predetermined particle size, but in this case, there is a problem that many are crushed to a particle size not more than the predetermined particle size and a loss is large.

In order to form pellets or honeycombs, a sol in which a platinum group salt or a metal oxide carrying a platinum group catalyst, zeolite or magnesium silicate, and silica sol are mixed is dried to obtain a predetermined sol. After gelling to a viscosity, the method of molding and firing, or by reducing the amount of silica sol, or using a silica sol with a small amount of water, a metal oxide supporting a platinum group salt or platinum group catalyst, There is a method of gelling by adding zeolite or magnesium silicate, kneading, shaping, and baking. However, the former method has a problem that an operation for drying and gelling the sol is necessary and a predetermined viscosity cannot be obtained unless the drying conditions are constant, and in the latter method, there is a problem during mixing. Since it gels, it is difficult to mix it uniformly, and therefore, there is a problem that an operation for uniform mixing is necessary with a kneader or the like.

In view of the above problems, it is an object of the present invention to form a catalyst body for removing odors and harmful gases simply and by uniformly dispersing the constituent components in the catalyst body.

[0010]

The present invention provides a sol in which a platinum group salt or a metal oxide carrying a platinum group, zeolite or magnesium silicate, and silica sol are mixed,
At least one selected from the group consisting of water-soluble divalent or higher-valent metal salts, substances that are acidic when dissolved in water, substances that are basic when dissolved in water, and surfactants were added and gelled. rear,
It is characterized in that a catalyst body is manufactured by molding and firing.

[0011]

According to the present invention, first, a platinum group salt or a metal oxide carrying a platinum group, zeolite or magnesium silicate, and silica sol are mixed to form a sol. Here, the zeolite or magnesium silicate used in the present invention is used as an adsorbent, and can adsorb and deodorize various indoor odor components as compared with conventional activated carbon that is generally used as an adsorbent. There is no variation in.

As the platinum group salt, chloroplatinic acid, palladium chloride, rhodium nitrate, etc. are used, and most of them are water-soluble and can be dissolved in silica sol, heated and pyrolyzed to give platinum, palladium or It becomes palladium oxide, rhodium or rhodium oxide, and these precious metals are activated by heating the catalyst body, deodorize the odorous substances in the air in contact with the catalyst body by oxidative decomposition, and adsorb them on zeolite or magnesium silicate. It acts as a catalyst for the oxidative decomposition of odorous substances and regenerates the adsorption capacity of the adsorbent.

As the noble metal catalyst, those which are previously supported on the surface of a metal oxide such as alumina may be used. In particular, by supporting it on the surface of alumina, it becomes possible to prepare a highly active catalyst.

Further, the silica sol used as the binder of the catalyst body loses its stability as a sol when the pH changes, an electrolyte is added, or the amount of water decreases.
It has the property of gelling and increasing viscosity. Therefore, the platinum group-supported metal oxide and the adsorbent may cause gelation during mixing, but in such a case, it is necessary to knead using a kneader or the like in order to uniformly disperse.

Therefore, if the sol at the time of mixing the platinum group salt or the metal oxide supporting the platinum group and the adsorbent with the silica sol has a low viscosity, it is easy to disperse uniformly, and the platinum group is supported. It is desirable that the metal oxide or adsorbent is mixed and then gelled. Here, when the amount of the adsorbent or the metal oxide supporting the platinum group is large, gelation may occur during the addition of the metal oxide or the adsorbent to the silica sol. In this case, the silica sol is diluted with water or the like in advance. By doing so, gelation can be prevented.

In the mixed sol thus prepared, a water-soluble divalent or higher valent metal salt, a substance which exhibits acidity when dissolved in water,
At least one selected from the group consisting of a substance that exhibits basicity when dissolved in water and a surfactant is added, gelled, molded and fired to obtain a catalyst body. Here, the water-soluble metal salt having a valence of 2 or more is a valence of 2 or more, such as a nitrate, an acetate, a sulfate or a chloride of barium, magnesium, calcium, copper, nickel, cobalt, aluminum, etc. Use a highly water-soluble salt.

This is because silica sol hardly causes gelation even when a large amount of monovalent cations is added, and the presence of polyvalent cations causes the charge balance of silica to be lost and gelation to easily occur. To do. Further, when a trivalent cation rather than a divalent cation is added, gelation can occur with a smaller amount. In addition, acids such as acetic acid and hydrochloric acid may be used as the gelling agent. This is because the silica sol is unstable at pH 4 to pH 7.

Further, the pH of the silica sol used is 2 to 4
In the case of about a certain degree, a gel can be formed by adding a base such as sodium hydroxide or potassium hydroxide and raising the pH of the mixed sol to 5 to 7. A surfactant such as an alkyl ammonium salt or alkyl glycine may be used as the gelling agent. These surfactants dissolve in water to dissociate ions such as alkyl ammonium ions,
This causes the silica sol to gel. The gel which is made into a gel and has a predetermined viscosity is formed into a desired shape such as a pellet shape or a honeycomb shape, and then dried and fired to obtain a catalyst body.

[0019]

EXAMPLE For the platinum group catalyst used in the present invention, it is desirable to add to the silica sol alumina in which the platinum group catalyst is previously supported. By supporting a platinum group catalyst on alumina,
The activity becomes higher than that in the case where a platinum group catalyst is supported on zeolite or magnesium silicate.

Further, the zeolite of the present invention is A type, X type, Y type.
It is possible to use various types of zeolites such as type and 10-membered ring type. Among them, copper ion-exchanged zeolite is particularly preferable because it has the best odor adsorption capacity.

The magnesium silicate of the present invention is a composition in which magnesium oxide such as magnesium orthosilicate, magnesium metasilicate, talc, magnesium tetrasilicate, magnesium trisilicate and the like, silicon dioxide and water are bonded at various ratios.

The content of the silica sol of the present invention is preferably 10 wt% or more of the solid content in the catalyst body. If it is less than 10 wt%, a sufficient adhesion effect as a binder of silica sol cannot be obtained.

It is desirable to include cerium oxide in the catalyst body of the present invention. By including cerium oxide in the catalyst body, the oxidative decomposition activity of the catalyst substance with respect to the hydrocarbon compound can be improved. Examples of the cerium oxide supporting method include a method in which cerium oxide is mixed with a metal oxide supporting a platinum group, a method in which a catalyst body is molded, then impregnated in an aqueous cerium nitrate solution, and then baked to obtain cerium oxide.

The content of the cerium oxide is preferably 2 to 15 wt% of the solid content in the catalyst body in terms of the amount converted as cerium oxide. When the content of cerium oxide exceeds 15 wt%, the oxidative decomposition characteristics of the catalyst begin to deteriorate,
If it is less than the above, a sufficient effect of adding cerium oxide cannot be obtained.

It is desirable to include barium oxide in the coating composition of the present invention. By including barium oxide in the catalyst,
The oxidative decomposition characteristics of the catalyst can be improved.

The content of barium oxide of the present invention is preferably 0.5 to 5 wt% of the solid content in the catalyst body. If the content of barium oxide exceeds 5% by weight, the catalyst body becomes brittle, and if it is less than 0.5% by weight, a sufficient addition effect of barium oxide cannot be obtained.

The same effect can be obtained by using barium carbonate instead of barium oxide of the present invention. The desirable amount of barium carbonate added is converted to the amount of barium oxide.
It is 0.5 to 5 wt%.

It is desirable to include titanium oxide in the catalyst body of the present invention. By including titanium oxide in the catalyst,
It is possible to improve the catalytic oxidation activity for nitrogen compounds such as ammonia.

The content of titanium oxide of the present invention is preferably 3 to 15 wt% of the solid content in the catalyst body. When the content of titanium oxide exceeds 15 wt%, the catalyst body becomes brittle, and 3
If it is less than wt%, a sufficient addition effect of titanium oxide cannot be obtained.

(Example 1) 800 g of γ-alumina, 6 g of chloroplatinic acid as Pt and 3 g of palladium chloride as Pd
g and 1,500 g of water were added and mixed well using a ball mill, followed by firing at 500 ° C. for 1 hour and pulverization to prepare a noble metal-supported alumina.

A mixed sol A was prepared by adding 175 g of the noble metal-supported alumina and 390 g of copper ion-exchanged zeolite to 1300 g of a silica sol aqueous solution containing 20 wt% of silica and having a pH of 9, and uniformly dispersing the mixture. In addition, aluminum nitrate nonahydrate 17
After adding g to form a gel, it was formed into pellets with a pelletizer. Then, it was dried at 100 ° C. for 8 hours and calcined at 500 ° C. for 1 hour to prepare a catalyst body A.

Further, it took 8 to 12 hours to dry the mixed sol A at 60 ° C. and to obtain a viscosity capable of molding, and the drying time greatly changed depending on the humidity.

Further, in the mixed sol A, the amount of silica sol was reduced to 700 g, and 175 g of noble metal-supported alumina and 390 g of copper ion-exchanged zeolite were added. If it was not used, it could not be uniformly dispersed, and the resulting catalyst body was brittle as compared with the catalyst body A due to the lack of the amount of binder.

Example 2 1300 g of a silica sol aqueous solution containing 20 wt% of silica and having a pH of 9 was added to 175 g of γ-alumina, 390 g of copper ion-exchanged zeolite, and chloroplatinic acid as Pt of 1.3.
g and palladium chloride as Pd, 0.65 g was added and uniformly dispersed to prepare a mixed sol. Further, 16 g of aluminum nitrate nonahydrate was added to form a gel, and the mixture was pelletized with a pelletizer. Then, it was dried at 100 ° C. for 8 hours and calcined at 500 ° C. for 1 hour to prepare a catalyst body.

Example 3 In Example 1, a mixed sol was prepared by adding 390 g of magnesium silicate instead of the copper ion-exchanged zeolite, and 20 g of aluminum nitrate nonahydrate was added.
After gelling, the mixture was pelletized with a pelletizer. After that, it is dried at 100 ℃ for 8 hours, and at 500 ℃ for 1 hour.
It was calcined for a time to prepare a catalyst.

(Example 4) In Example 1, various metal salts were added in place of aluminum nitrate nonahydrate to determine the minimum necessary amount of gelation. Sodium chloride, potassium nitrate, lithium nitrate trihydrate, magnesium nitrate 6
Hydrochloride, calcium nitrate tetrahydrate, copper nitrate hexahydrate, iron nitrate 9
The results were obtained for hydrate and cerium nitrate hexahydrate.
It shows in (Table 1). When a monovalent metal salt such as sodium chloride, potassium nitrate or lithium nitrate trihydrate was added, gelation did not occur even when it was added until a saturated solution was reached.

As shown in (Table 1), the use of a trivalent metal salt tends to cause gelation in a smaller amount than in the case of a divalent metal salt. Although the metal salt was added as it is in this example, the same effect can be obtained by dissolving the metal salt in water and adding the aqueous solution to the mixed sol.

[0038]

[Table 1]

(Example 5) In Example 1, various acids were added in place of the aluminum nitrate nonahydrate to examine the gelation promoting effect. I examined hydrochloric acid, nitric acid, and acetic acid,
In both cases, gelation occurred at pH near 5 to 6.

Example 6 In Example 3, the pH was 9
A mixed sol was prepared by using a silica sol of pH 3 containing 20 wt% of silica in place of the silica sol of. To this mixed sol, various metal salts which were dissolved and showed basicity were added. When sodium hydroxide, potassium hydroxide, and lithium hydroxide were examined, gelation occurred at a pH of about 5 to 6 in all cases. In addition, although the metal salt which is dissolved and exhibits basicity is added in this example, the same effect can be obtained by adding an aqueous solution having basicity to the sol.

(Example 7) In Example 1, instead of aluminum nitrate nonahydrate, various surfactants were added to the mixed sol in an amount of 5% by weight. Alkyl glycine,
Three types of surfactants each containing alkyltrimethylammonium bromide and oxyethylene dodecylamine as main components were examined, and gelation occurred in all cases.

[0042]

As described above, the method for producing a catalyst body of the present invention can form a uniformly mixed catalyst body by a simple method.

Front page continuation (72) Inventor Kyoe Yamade 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A sol prepared by mixing a platinum group salt or a metal oxide carrying a platinum group, zeolite or magnesium silicate, and silica sol is dissolved in a water-soluble divalent or higher valent metal salt or water to acidify it. At least one selected from the group consisting of the substance shown, a substance showing basicity when dissolved in water, and a surfactant is added, gelled, molded, and fired to produce a catalyst body. Method for producing catalyst body.