JP2002263449A - Activated carbon filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To offer optimum conditions for the application of a room temperature cleaning catalyst to an activated carbon filter. SOLUTION: The active components of this activated carbon filter comprises >=3 wt.% room temperature cleaning catalyst, >=3 wt.% photocatalyst and >=70 wt.% activated carbon. The room temperature cleaning catalyst is obtained by carrying a noble metal on an oxide with oxygen deficiencies introduced by reduction treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an environmentally hazardous substance such as carbon monoxide (CO) and odorous substances and nitrogen oxides (NO).
The present invention relates to an activated carbon filter carrying a room-temperature purifying catalyst capable of easily purifying and removing hydrocarbons (HC), formaldehyde often generated in a house, and ethylene gas which causes deterioration of food freshness at room temperature (room temperature).
This activated carbon filter is suitably used for an air purifier and adsorbs and removes environmentally harmful substances such as odorous gas and toxic gas.

[0002]

2. Description of the Related Art Conventionally, adsorbents such as activated carbon and zeolite have been used to remove odorous substances and harmful gases, but these adsorbents require means for treating the adsorbed components.

[0003] Further, in the purification of carbon monoxide gas, which is a harmful gas, the ability to purify and remove carbon monoxide gas in a lower temperature range in a short time is required. However, conventional catalysts still lack purification ability at room temperature, and further improvement in purification performance is required.

[0004] The effect of formaldehyde on the human body is as follows:
Primarily an irritating effect on the eyes, nose and throat, specifically accompanied by symptoms such as discomfort, lacrimation, combing, coughing, nausea and dyspnea. Sources in residential space include smoking, use of heating appliances, household items, furniture and building materials. Formaldehyde is also used as a raw material for plywood / vertical board bonding tide, which is often used as a urea-formaldehyde adhesive, and as a preservative for wallpaper adhesives. In contrast, the Ministry of Health and Welfare has set a standard value for indoor formaldehyde concentration of 0.1 mg / Nm ³ (= 80 pp).
b) It states that:

[0005] In recent years, formaldehyde has been regarded as one of the causative substances of the sick house syndrome, and material manufacturers and house makers have been using a material that does not generate formaldehyde before constructing it or transferring it to the owner after construction. However, the above treatment does not always meet the standards set by the Ministry of Health and Welfare.

[0006] On the other hand, adsorbents such as activated carbon and zeolite are used to remove volatile formaldehyde. However, these adsorbents have a long service life, require periodic replacement, and require economic expenditure. Becomes Further, a means for newly treating the component adsorbed on the adsorbent is required.

[0007] As a device for removing odorous substances and the like in a room at normal temperature, a filter for an air purifier incorporating activated carbon is generally known. In addition, air purifier filters using photocatalysts are also commercially available.

[0008] In addition, a method of removing with ozone, a method of using a photocatalyst, and a device and a filter thereof have been put on the market. However, ozone requires a concentration higher than the regulated value of the ozone concentration in order to exhibit its effect, and further requires a catalyst for treating ozone.
As for the photocatalyst, an artificial light source serving as an excitation source of the photocatalyst is required, and if the light source is constantly irradiated to the photocatalyst, an electricity cost for operating the light source is also required, which is expensive.

Japanese Unexamined Patent Publication No. Hei 6-219721 discloses that metal oxide particles containing CeO _{2 in} which noble metal particles are uniformly mixed, and the metal oxide is composed of CeO ₂ , Zr
A catalyst containing one or more of O ₂ , TiO ₂ and SnO ₂ is disclosed. This catalyst, as a catalyst for purifying carbon monoxide to carbon dioxide gas, is a catalyst in which an anionic vacancy is formed on the surface by coprecipitation of a metal oxide containing noble metal particles,
It shows high reactivity without hydrogen reduction treatment. However, its purification performance is evaluated under a temperature condition of 150 ° C. or higher, and no mention is made of purification activity in a room temperature range.

On the other hand, a specific catalyst has been proposed as a method for oxidatively decomposing odorous substances and harmful gases in the atmosphere. For example, JP-A-10-296087 discloses that a catalyst containing zirconia or ceria as essential and carrying at least one of Ag, Pd, Pt, Mn, and Rh can be used as a catalyst for oxidative decomposition of trimethylamine. . However, even in this case, the disclosed catalyst is merely evaluated for its purifying ability under the temperature condition of 200 ° C. in the examples. Further, there is no description of oxygen deficiency in the oxides used in the above catalyst. Therefore, it is unlikely that the above catalyst has sufficient trimethylamine decomposition ability at room temperature.

International Patent Application WO-91 / 01175 discloses that a catalyst for oxidizing an oxidizing substance at a low temperature range includes iron oxide, ceria, zirconia, copper oxide, rare earth elements, manganese oxide, vanadium oxide and chromium oxide. A catalyst in which a noble metal is supported on a selected kind of reducing metal oxide is 30 ° C
There is a disclosure that an oxidizing substance having a molecular weight of 50 or less is oxidized at a temperature up to. Focusing on the reduction temperature as a condition for producing this catalyst, there is a description that the reduction treatment was performed at room temperature. However, it is impossible to introduce an oxygen vacancy having the function of the present invention into the metal oxide at room temperature.

JP-A-7-51567 discloses a catalyst in which activated carbon is suspended in an aqueous solution in which molybdenum or cerium and platinum are dissolved, and the molybdenum or cerium and platinum are supported on the activated carbon using heat or a reducing agent. There is a disclosure. However, this catalyst does not mention that any treatment is performed after loading.

In general, a filter for an air purifier using activated carbon exhibits a deodorizing ability by physically adsorbing odorous substances onto activated carbon. However, the amount of activated carbon adsorbed has an upper limit, and the deodorizing performance exceeding the saturated adsorbed amount is not exhibited. For this reason, the life of the filter is short, and regeneration processing is indispensable for long-term use, and when regeneration is not performed, the filter must be replaced.

In a filter using a photocatalyst, light irradiation for operating the photocatalyst is indispensable for purifying harmful substances, which requires a light source such as a mercury lamp.
For this reason, an air purifier or the like using a filter using a photocatalyst has a disadvantage that the equipment price and the running cost are extremely high.

Further, it is considered that ethylene gas contained in the air promotes the physiological action of the fruits and vegetables, and the freshness of the fruits and vegetables is lowered by ripening and aging. Therefore, methods for decomposing ethylene with ozone or hydrogen peroxide or adsorbing and removing ethylene have been proposed for maintaining the freshness of fresh food.

However, among the above methods, the adsorption type has a short duration of the effect. Therefore, when ozonolysis used to make up for the disadvantages of the adsorption type, or when using a photocatalyst together,
There is a problem in that the device related to the removing means becomes large-scale and costly, and a space for the device is required.

[0017]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has been made at a normal temperature (a region including a normal room temperature and a temperature lower than normal room temperature which does not require special heating and cooling). It is an object of the present invention to propose a room temperature purification catalyst capable of decomposing and purifying harmful gases and harmful organic substances such as formaldehyde and ethylene, and having little deterioration over time. Another object of the present invention is to develop a use of the room temperature purification catalyst. For example, the room temperature purification catalyst is applied to an activated carbon filter for an air purifier.

[0018]

The room temperature purification catalyst of the present invention comprises a noble metal supported on an oxide introduced with oxygen deficiency by a reduction treatment. Since the noble metal is supported on the oxide having oxygen deficiency, it has a function of purifying environmental load substances in the air at normal temperature. Odor substances,
Examples thereof include hydrocarbons such as carbon monoxide and ethylene, and nitrogen compounds. Then, the ordinary-temperature purification catalyst is supported on activated carbon with a predetermined composition. In another aspect of the present invention, a normal temperature purification catalyst and a photocatalyst are supported on activated carbon with a predetermined composition.

The oxide forming the groove of the ordinary temperature purification catalyst of the present invention is preferably at least one selected from transition metal oxides and rare earth oxides. As the transition metal oxide, at least one selected from oxides of zirconium, iron, manganese, cobalt, nickel, copper, chromium, molybdenum, and niobium can be used. As the rare earth oxide, at least one selected from oxides of cerium, yttrium, neodymium, praseodymium, and samarium can be used.

It is preferable that cerium oxide is contained as an oxide constituting the room temperature purification catalyst of the present invention, and at least a part of the cerium oxide is present in an oxygen deficient state by a reduction treatment. The oxygen deficiency in CeOn is 1.5 ≦ n
It is preferable that the oxygen deficiency is <2. And C
In eOn, it is preferable that the oxygen deficiency is 1.5 ≦ n ≦ 1.8. The catalyst containing cerium oxide is suitable for purifying at least one of environmentally harmful substances such as formaldehyde, trimethylamine, methyl mercaptan, and acetaldehyde in the air at normal temperature.

The oxide constituting the room-temperature purification catalyst of the present invention is preferably an oxide containing cerium oxide and zirconium oxide, wherein at least a part of the cerium oxide mainly exists in an oxygen deficient state by the reduction treatment. Further, it is preferable that the cerium oxide and the zirconium oxide form a solid solution or a composite oxide.

The oxide composed of cerium oxide and zirconium oxide preferably has a specific surface area of at least 50 m ² / g after a reduction treatment at 500 ° C. for 1 hour. Under different conditions, the oxide composed of cerium oxide and zirconium oxide preferably has a specific surface area after reduction treatment at 800 ° C. for 1 hour of 15 m ² / g or more.

The temperature of the reduction treatment is 100 ° C. to 800 ° C., more preferably 200 ° C. to 600 ° C.

The room temperature purification catalyst of the present invention may be used by being supported on at least one carrier selected from titanium oxide, alumina, silica, zeolite, cordierite, sepiolite, and activated carbon.

The purifying reaction of the normal temperature purifying catalyst of the present invention for odorous substances is performed at a purifying reaction temperature of 25 ° C. and a space velocity of 6000.
Under the condition of 00h ^-1 , the purification rate after 20 minutes from the start of the purification reaction is 50% or more. Further, the purification reaction for carbon monoxide of the room temperature purification catalyst of the present invention has a purification rate of 40% or more 30 minutes after the start of the purification reaction at a purification reaction temperature of 25 ° C. and a space velocity of 120,000 h ⁻¹ .

In the method of using the room temperature purification catalyst of the present invention, the room temperature purification catalyst may be used by converting an environmentally hazardous substance such as carbon monoxide, nitrogen oxide, ethylene, aldehyde, amine, mercaptan, fatty acids, odorous substance, aromatic carbonized substance. By contacting air containing at least one of hydrogens, these environmentally harmful substances are purified at normal temperature.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The room temperature purification catalyst of the present invention is a catalyst in which a noble metal is supported on an oxide into which oxygen deficiency has been introduced by a reduction treatment. This room temperature purification catalyst can purify harmful substances in air at room temperature.

In the oxide which is in an oxygen-deficient state by this reduction treatment, a part of the oxygen forming the oxide is desorbed from the oxide by the reduction treatment, and the oxide is activated in an oxygen-deficient state. ing. By supporting the noble metal on the activated oxide, durability can be maintained in a normal temperature range, and harmful substances can be purified. The normal temperature here refers to a temperature range in which the normal temperature purification catalyst of the present invention does not lose the introduced oxygen deficiency state described later. That is,
The temperature range is 50 ° C or lower, more preferably 10 to 40 ° C.

As the oxide, at least one selected from transition metal oxides and rare earth oxides can be used. Examples of the transition metal oxide include oxides belonging to transition metals such as iron, manganese, cobalt, chromium, nickel, copper, yttrium, zirconium, molybdenum, niobium, and titanium. Also, as rare earth oxides,
Oxides of cerium, neodymium, praseodymium and samarium belonging to lanthanum series elements can be used.

As the noble metal component carried on the oxide, at least one of Pt, Pd, Pb, Ir, Au, and Ru is used.

The oxygen-deficient state introduced by the reduction treatment means a state in which the molar amount of oxygen bonded as an oxide is smaller than a predetermined value. For example, in the case of cerium oxide, this corresponds to less than 2 times the molar amount of oxygen atoms relative to cerium atoms. That is, the oxide undergoes a reducing action by the reduction treatment described below, and a part of oxygen is eliminated, so that the oxide becomes an oxygen-deficient state. The formation of this oxygen-deficient state enhances the activation of the oxide itself, weakens the state of adsorption of the harmful substance to the noble metal, and utilizes the oxygen activated via the oxygen-deficient portion to remove the harmful substance. It is considered that since the oxidation reaction proceeds, it is possible to purify harmful substances in a normal temperature range.

In the reduction treatment here, it is preferable that the above-mentioned oxide mixed with a noble metal is treated in a reducing gas stream at a temperature range of 100 ° C. to 800 ° C. for about one hour. That is, when the oxide contacts the reducing gas at a high temperature, a part of the oxygen of the oxide is combined with the reducing gas and removed. As a result, part of the oxide becomes an oxygen-deficient state, and an oxide in an oxygen-deficient state is formed. Examples of the reducing gas used in the reduction treatment include a reducing gas such as hydrogen and carbon monoxide, a hydrocarbon such as methane, and formaldehyde. As the concentration of these reducing gases, 0.1.
1 vol% to 100 vol%, more preferably 1 vol% to 100 vol% is good. Furthermore, the above-mentioned transition metal oxides and rare earth oxides can be brought into an oxygen-deficient state by a reduction treatment with a reducing agent represented by hydrazine, aluminum borohydride or the like. In addition, the shape of the sample used for the reduction treatment is not particularly limited.

Among the room temperature purification catalysts of the present invention, there are catalysts containing cerium oxide, zirconium oxide and noble metal as oxides. In this catalyst, due to the reduction treatment, at least a part of cerium oxide mainly exhibits activity in an oxygen deficient state and shows activity in a normal temperature range. Amines, mercaptans, aldehydes, fatty acids, odorants,
Organic substances such as aromatic hydrocarbons can be purified by oxidative decomposition at room temperature.

The purification reaction of odorous substances by this catalyst is 2
The purification rate at 20 minutes after the start of the purification reaction at 5 ° C. is preferably 50% or more. In this case, the initial concentration of the odorant is
As an example, in the case of formaldehyde, it is 100 ppb and the space velocity is 600,000 h ⁻¹ .

The purification reaction of carbon monoxide is carried out at a temperature of 25 ° C. and a space velocity of 120,000 h ^−1.
It is preferable that the purification rate after minutes is 40% or more. In this case, the initial concentration of carbon monoxide is 220 ppm.

The air in the present invention includes the exhaust gas discharged from the atmosphere and the internal combustion engine, etc., and also refers to the atmosphere in the interior of a house, the atmosphere in a vehicle interior, etc., and refers to the so-called general atmosphere of a living space.

When the oxygen-deficient oxide of the room temperature purification catalyst of the present invention is a mixture of cerium oxide and zirconium oxide, it is preferable that both exist as a solid solution or a complex oxide. Since the cerium oxide and the zirconium oxide form a solid solution or a complex oxide, the oxide deficiency state of the oxide is easily formed, and the oxygen deficiency state formed by the reduction treatment can be stably maintained. It is possible to maintain the catalytic activity in a normal temperature range for a long period of time. Therefore, the room temperature purification catalyst can purify harmful substances in the air more efficiently in a room temperature range over a long period of time.

The room temperature purification catalyst of the present invention comprises a noble metal, cerium oxide and zirconium oxide in an oxygen-deficient state, and a rare earth oxide such as yttrium, lanthanum, neodymium, praseodymium, iron oxide, manganese oxide as a third component. It may contain one selected from transition metal oxides such as cobalt oxide, chromium, nickel, and copper. By blending these third components, the oxygen deficiency state of cerium oxide and zirconium oxide is stably maintained, and contributes to the maintenance of purification performance.

When both cerium oxide and zirconium oxide are used, the mixing molar ratio of Ce and Zr is 100:
The ratio is from 1: 1 to 100, preferably from 20: 1 to 1:10, and more preferably from 5: 1 to 1: 1. By setting the content in this range, the above-described oxygen deficiency state can be stably maintained. A large amount of cerium oxide is preferable because an oxygen deficiency state is easily formed.

The amount of the noble metal is 0.01 to 20% by weight, more preferably 0.6 to 3.0% by weight, based on the oxide of cerium and zirconium. If the amount of the noble metal is less than 0.01% by weight, the activity of the catalyst cannot be obtained, which is not preferable.
Further, even if it is used in an amount exceeding 20% by weight, the purification efficiency is not improved for the addition, and a large amount of expensive noble metal is used, which increases the cost, which is not preferable.

The solid solution or composite oxide of cerium and zirconium is preferably formed by a coprecipitation method.
A method other than the coprecipitation method can be used as long as the method can be synthesized at the above mixing ratio. The precipitate generated by the coprecipitation method can be converted into an oxide by firing or the like.

Noble metals are carried by cerium oxide and zirconium oxide by impregnation, evaporation to dryness, supercritical fluid method and the like. Further, when formed by the coprecipitation method with the above-mentioned composite oxide, a noble metal may be supported in coexistence. After the noble metal is supported, a so-called reduction treatment is performed using a reducing gas, as described above, to form an oxygen deficiency state of the oxide, thereby imparting catalytic activity.

The noble metal supported on the room temperature purification catalyst preferably has a particle size of 5 nm or less, more preferably 1 nm or less, in order to maintain the activity of the catalyst.

The above-mentioned catalyst component can be used by being supported on at least one kind of carrier selected from titanium oxide, alumina, silica, zeolite, sepiolite and activated carbon, which are generally known as catalyst carriers. The catalyst component is
It can be carried on the carrier selected above, formed into a pellet shape, and further used by being held on a honeycomb-shaped substrate or the like.

Although the mechanism of the ordinary temperature purification catalyst is not clear, at least a part of the cerium oxide and zirconium oxide becomes oxygen deficient by the reduction treatment, and the oxygen activated by the oxide is reduced on the noble metal. In addition to increasing the reactivity, the oxidation reaction by precious metals is promoted, and the presence of oxygen deficiency weakens the adsorption of odors and harmful substances to precious metals, causing odorous substances, carbon monoxide, nitrogen oxides, and other environmental loads. The purification reaction of substances and the like proceeds. It is presumed that the cerium oxide and zirconium oxide purify the purified oxide by promoting desorption from the catalytically active site. For this reason, it is estimated that adsorption and poisoning of the noble metal to the catalytically active point is suppressed, and the catalytic activity in a normal temperature range is maintained, thereby improving the purification performance.

The reduction treatment is the same as in the case of the oxide described above, and it is preferable to treat the compounded and formed catalyst in a reducing gas stream at a temperature of 100 ° C. to 800 ° C. If the treatment temperature is lower than 100 ° C., reduction does not proceed and a desired oxygen deficiency state cannot be formed, which is not preferable. On the other hand, when the treatment temperature exceeds 800 ° C., the specific surface area of the oxide becomes small, and the catalytic activity decreases, which is not preferable.

Examples of the reducing gas include hydrocarbons such as hydrogen, carbon monoxide, and methane, and reducing gases such as formaldehyde. The concentration of these reducing gases is preferably 0.1% by volume to 100% by volume. However, reduction by other chemicals than the above-described reducing gas is also possible, and is not particularly limited.

For example, the cerium oxide and the zirconium oxide subjected to the reduction treatment at 500 ° C. preferably have a total specific surface area of 50 m ² / g or more. Further, in the case of the condition of 800 ° C., it is preferable that the sum of the specific surface areas of both is 15 m ² / g or more.

The room temperature purification catalyst of the present invention, which contains a cerium oxide and a noble metal, and at least a part of the cerium oxide is present in a state of oxygen deficiency by a reduction treatment, is characterized by that Thus, an excellent effect of purifying harmful substances in a normal temperature range is exhibited.

The room temperature purification catalyst containing cerium oxide and a noble metal is subjected to cerium oxide CeOn in the reduction treatment.
In the case where the composition ratio of n in the oxygen deficiency state is in the range of 1.5 ≦ n <2, more preferably 1.5 ≦ n ≦ 1.8, an excellent effect of purifying formaldehyde in the air is exhibited. . It is difficult to create a state where the n value is less than 1.5 under ordinary conditions of reduction and elemental analysis. Further, in order to form an oxygen vacancy, the n value needs to be less than 2 and is 1.8.
When the following oxygen vacancies are formed, more sufficient activity as a catalyst can be obtained. Note that the oxygen deficiency state of the oxide can be measured by, for example, X-ray diffraction.

It is preferable that the amount of oxygen deficiency in the surface layer of the cerium oxide particles is 1.5 ≦ n ≦ 1.8 in order to increase the activity of the catalyst. Here, the surface layer means a layer about 100 nm from the surface.

The amount of the noble metal supported on the cerium oxide was 0.1 g per 150 g of the cerium oxide.
By containing g to 20 g, more preferably 0.5 to 5 g, harmful substances can be purified in the room temperature range.
If the amount is less than 0.1 g, the activity of the catalyst cannot be obtained, which is not preferable. Further, even if the precious metal is used in an amount of more than 20 g, the purification efficiency is not improved for the addition, and a large amount of expensive precious metal is used.

The noble metal components include Pt, Pd, Rh,
At least one of Au and Ru is used. The noble metal is supported on cerium oxide by an impregnation method, an evaporation to dryness method, a supercritical fluid method, or the like. After the noble metal is supported, catalytic activity can be obtained by reducing the cerium oxide by performing a reduction treatment using hydrogen or the like as in the above catalyst.

The reduction treatment is the same as in the case of the above oxide, and it is preferable to treat the compounded and formed catalyst in a reducing gas stream at a temperature of 100 ° C. to 800 ° C.
Examples of the reducing gas include hydrocarbons such as hydrogen, carbon monoxide, and methane, and reducing gases such as formaldehyde. The concentration of these reducing gases is preferably 0.1% by volume to 100% by volume. However, reduction with other chemicals other than the above-described reducing gas is also possible, and there is no particular limitation.

This catalyst can be used by being supported on at least one carrier selected from clay minerals represented by alumina, silica, zeolite, titanium oxide, cordierite, activated carbon, and sepiolite, similarly to the above-mentioned catalyst. Further, the catalyst component may be coated on a substrate in a powder state, or may be supported on the carrier selected above to form a pellet. Furthermore, it can also be used by holding it on a honeycomb-shaped base or the like.

By using the cerium oxide and the noble metal as catalyst components, it is possible to purify formaldehyde, volatile organic compounds called VOCs, and odor substances in a room temperature range.

The room temperature purification catalyst of the present invention can effectively remove ethylene which is generated from vegetables and fruits such as fruits and vegetables, and is considered to reduce freshness of fresh food products.

In the case of a catalyst used for purifying ethylene, yttrium oxide,
It may contain at least one selected from lanthanum oxide, iron oxide, manganese oxide, and copper oxide. When fresh food is placed in an environment for keeping freshness (for example, case, container box, etc.), air introduced into the environment and brought into contact with fresh food should be passed through the catalyst. Can maintain freshness.

The shape of the catalyst in this case may be a powder, a monolith, a filter, or may be applied to the inner wall of the container. Further, the above catalyst may be packed with an air-permeable material. By using this ethylene purification catalyst, ethylene can be decomposed even at room temperature or lower, so that physiological effects of fruits and vegetables can be suppressed, ripening and aging can be suppressed over time, and freshness can be easily maintained. Furthermore, since this room temperature purification catalyst is an oxidation reaction, it generates carbon dioxide gas and consumes oxygen along with ethylene decomposition, so that the low oxygen concentration, high carbon dioxide concentration, and low ethylene concentration which are desirable gas compositions for maintaining freshness of fruits and vegetables are obtained. An atmosphere can be formed.

Although the mechanism of the purification catalyst of the present invention is not always clear, the presence of oxygen-deficient cerium oxide activates the noble metal, weakens the state of adsorption of the substance to be purified on the noble metal and reduces oxygen deficiency. It is presumed that the oxygen activated via this reacts with ethylene as the substance to be purified and is desorbed and purified as an oxide. For this reason, it is assumed that adsorption and poisoning to the noble metal is suppressed, the catalytic activity in the room temperature range is maintained, and the purification performance is improved.

The room temperature purification catalyst of the present invention can be used at room temperature. However, it can be used in a temperature range as long as the catalyst does not lose its oxygen-deficient state. That is, even when used in a temperature range of about 50 ° C. to about 100 ° C. as well as at normal temperature, the effect can be sufficiently exhibited. However, when the room temperature purification catalyst of the present invention is exposed to 200 ° C. or more for a long time, oxygen deficiency disappears and high activity is lost. Therefore, the operating temperature is preferably 200 ° C. or less, more preferably 100 ° C. or less.

The room temperature purification catalyst of the present invention may contain activated carbon. It is preferable that at least a part of the oxide contains cerium oxide in an oxygen-deficient state. With this configuration, in addition to the adsorption capacity of the activated carbon, the interaction between the oxide and the noble metal enables the purification reaction at room temperature and the purification performance to be maintained for a long time.

The reduction treatment temperature of the ordinary-temperature purification catalyst is preferably in the range of 200 ° C. to 600 ° C. in order to prevent the burning and extinction of activated carbon. Under these conditions, the catalyst that has undergone the reduction treatment retains the activated carbon and provides cerium oxide in an oxygen-deficient state, thus providing high removal performance for environmentally harmful substances such as formaldehyde, acetaldehyde, and carbon monoxide. it can.

[0064] The ordinary temperature purification catalyst of the present invention is less deteriorated in purification ability than conventionally known activated carbon. For example, CO
(250 ppm) + oxygen (20%) + nitrogen (balance)
CO purification rate by one-pass test under circulation is from the start of the reaction
After one hour, the catalyst of the present invention can maintain 70%, compared with 20% for activated carbon.

The purification of acetaldehyde will be described as an example. Acetaldehyde is adsorbed on activated carbon, and then has a catalytic purification effect of Pt / CeO ₂ present in the vicinity, and is subjected to a catalytic reaction before the activated carbon reaches saturated adsorption. Acetaldehyde can be purified. As a result, a decrease in adsorption removal performance can be suppressed.

Further, by adsorbing the substance to be purified on the activated carbon, it is possible to reduce, for example, the amount of the reactant which comes into contact with Pt / CeO ₂ having a catalytic action per unit time, thereby reducing the poisoning by the adsorbed substance. Suppression and catalyst purification performance can be maintained.

This catalyst is preferably used by being supported on a carrier or formed into pellets or honeycombs.

[0068]

The present invention will be described below in detail with reference to examples.

Example 1 2 g of Pt was supported on 150 g of cerium oxide powder, and this powder was formed into a pellet having a diameter of 1 to 2 mm. Thereafter, the resultant was subjected to a reduction treatment at 500 ° C. for 1 hour in N ₂ gas containing 5% of H ₂ to prepare a room temperature purification catalyst.

Example 2 A mixed solution was prepared by dissolving cerium (III) nitrate and zirconium nitrate in a molar ratio of Ce / Zr = 5/1, and ammonia water was added dropwise while stirring the aqueous solution. Then, the aqueous solution was neutralized and precipitated. Subsequently, an aqueous solution containing an aqueous solution of hydrogen peroxide having a mole number of セ of the cerium ion contained in the aqueous solution and alkylbenzenesulfonic acid at 10% of the weight of the obtained oxide was added dropwise and stirred.

The obtained slurry was dried and the coexisting ammonium nitrate was removed by evaporation and decomposition to obtain oxide solid solution powder CeO ₂ .ZrO ₂ .

This oxide solid solution powder CeO ₂ .ZrO ₂
2 g of Pt was supported on 150 g. This Pt-supported oxide solid solution powder was formed into a pellet having a diameter of 1 to 2 mm. Thereafter, under the same conditions as in Example 1, a reduction treatment was performed in a reducing atmosphere with hydrogen to produce a room temperature purification catalyst.

(Example 3) In Example 2 described above,
A normal temperature purification catalyst was produced in the same manner as in Example 2 except that the molar ratio of e / Zr was changed to 1/1.

Example 4 Aluminum nitrate, zirconium nitrate and cerium nitrate in a molar ratio of 2.4: 0.02
A 6-liter aqueous solution (solution A) mixed and dissolved at a ratio of 5: 0.25 and a solution (solution B) in which ammonia water and ammonium carbonate were mixed and dissolved at a molar ratio of 8.3: 0.08 were prepared. , B were mixed and stirred. After washing the oxide precursor precipitated from the mixed solution, it was dried and calcined at 650 ° C. for 1 hour. A composite oxide in which alumina, ceria, and zirconia were uniformly dispersed was obtained. Thereafter, a reduction treatment was performed under the same conditions as in Example 2 to produce a room temperature purification catalyst.

Comparative Example 1 The catalyst of Comparative Example 1 was a catalyst prepared in the catalyst preparation step of Example 2 without performing a reduction treatment.

(Comparative Example 2) 2 g of Pt was carried on 150 g of silicon oxide powder, and this powder was formed into a pellet having a diameter of 1 to 2 mm. Thereafter, the catalyst was formed by a reduction treatment in a reducing atmosphere with hydrogen under the same conditions as in Example 1.

Comparative Example 3 Pt / Ce was prepared by coprecipitation using cerium nitrate, chloroplatinic acid and solid NaOH.
O ₂ powder was prepared. Pt loading is 2g / 150gC
eO ₂ . The precipitate formed is filtered, washed, and
Fired at 00 ° C. This catalyst did not undergo reduction treatment.

(Evaluation of catalysts)
The purification performance of CO was evaluated under the following conditions.

The measurement of the CO purification rate was performed by measuring CO: 220 pp.
m, O ₂ : 20%, N ₂ : remaining amount, flow rate 5 L / min, space velocity 120,000 h ⁻¹ , and normal temperature. CO
The purification rate was determined by measuring the residual CO concentration 30 minutes after the start of the reaction. Table 1 shows the results.

[0080]

【table 1】

The catalyst of Example 3 was evaluated under the condition of 24,000 h ^{-1 at} a reduced space velocity.
The purification rate was 100%.

The constituent catalysts of the above-mentioned examples were prepared at room temperature (room temperature).
Shows that CO can be purified into CO ₂ .

In particular, as shown in Examples 1 to 4, the oxygen-deficient state is formed in the oxide such as cerium oxide by performing the reduction treatment, so that the purification reaction by the noble metal can be enhanced at room temperature. .

In order to maintain the cerium oxide in an oxygen-deficient state, it is preferable that the cerium oxide be present as a CeO ₂ .ZrO ₂ composite oxide or a solid solution (Examples 2 to 4). Furthermore, as shown in Example 2, when the compounding molar amount of CeO ₂ is large (compared with Example 3), the purification efficiency is higher.

The catalyst of Comparative Example 1 has the same composition as that of Example 2, but has not been subjected to a reduction treatment. Therefore, the oxide does not form an oxygen deficient state and does not exhibit a purifying action at room temperature. Since the catalyst of Comparative Example 2 is a silicon oxide which is not the oxide specified in the present invention, even if the reduction treatment is performed,
Purification rate is low. The catalyst of Comparative Example 3 has the same composition as the catalyst of Example 1, but the reduction rate of CO at room temperature is low because the reduction treatment is not performed. This indicates that the oxide specified in the present invention, which can form an oxygen deficient state by the reduction treatment, is effective as a normal-temperature purification catalyst.

(Example 5) The purification performance of acetaldehyde was evaluated using the same catalyst sample as in Example 2 which was subjected to reduction treatment at 500 ° C for 1 hour in N ₂ gas containing 5% H ₂ .

Catalyst sample amount 0.1 g Evaluation gas is acetaldehyde (O ₂ 20% / N ₂ balance) 5 L Initial concentration of acetaldehyde: 36 ppm, 72 ppm
270 ppm, the evaluation method was that a catalyst sample and an odor analysis-containing odor bag (manufactured by Omi Odair Service Co., Ltd.) containing the evaluation gas were allowed to stand at room temperature, and after 1 hour, 2 hours, 3 hours, 24 hours, and The residual acetaldehyde concentration in the bag after 96 hours was quantified, and the amount of acetaldehyde removed was calculated from the difference from the acetaldehyde concentration in the blank bag not containing the catalyst sample.

(Comparative Example 4) The catalyst prepared in Example 2 without reduction treatment was used as a catalyst sample of Comparative Example 4, and the same evaluation as in Example 5 was performed.

(Comparative Example 5)
Comparative Example 5 was evaluated under the same conditions as in Example 5 using activated carbon powder as a catalyst.

FIG. 1 (initial concentration: 36 ppm) FIG.
(Initial concentration 72 ppm) Figure 3 (Initial concentration 270 ppm)
Is shown in the graph.

Regarding the amount of acetaldehyde removed from the catalyst sample of Comparative Example 4 (without reduction treatment), the purification rate was lower at any concentration as compared with the case where the activated carbon of Comparative Example 5 was used. This shows that the acetaldehyde removal amount of the catalyst of Example 5 of the present invention is higher than that of the activated carbon of Comparative Example 5. This indicates that the catalyst of Example 5 has the ability to purify acetaldehyde at room temperature.

(Example 6) Using 0.1 g of the catalyst sample of this example used in Example 5, the purification performance of formaldehyde was examined.

The evaluation gas was formaldehyde (O ₂ 20%
/ N ₂ balance) 5L The evaluation method is as follows: a catalyst sample and an odor analysis odor bag (made by Omi Odair Service) containing an evaluation gas are allowed to stand at room temperature.
After 1 hour, 3 hours, and 24 hours, the concentration of formaldehyde remaining in the bag was measured with a formaldehyde detector tube (manufactured by GL Sciences), and the time-dependent change in the formaldehyde concentration in the bag was determined.

Comparative Example 6 The same evaluation as in Example 6 was performed using the activated carbon used in Comparative Example 5. FIG. 4 shows the results.

As shown in FIG. 4, it can be seen that the catalyst of Example 6 has higher formaldehyde purification performance than the activated carbon of Comparative Example 6. Therefore, it is shown that the catalyst of Example 6 can also purify formaldehyde at room temperature.

(Example 7) The catalyst used in Example 5 was used in 0.1 ml.
The purification performance of methyl mercaptan was examined using 1 g.

The evaluation gas was methyl mercaptan (O ₂ 20
% / N ₂ balance) 5L The evaluation method was as follows. A odor analysis bag (made by Omi Odoair Service) containing a sample and an evaluation gas was allowed to stand at room temperature, and after 1 hour, 3 hours, and 24 hours. The residual methyl mercaptan concentration in the gas was measured using an FPD gas chromatograph (manufactured by Shimadzu: GC-
15A), and the change over time in the methyl mercaptan concentration in the bag was determined.

Comparative Example 7 Purification performance was evaluated in the same manner as in Example 7 except that the activated carbon used in Comparative Example 5 was used. FIG. 5 shows the results.

As shown in FIG. 5, the catalyst of Example 7 was
It can be seen that the purification performance of methyl mercaptan is higher than that of the activated carbon of Comparative Example 7. Therefore, it is shown that the catalyst of Example 7 can also purify odorous substances such as methyl mercaptan at normal temperature.

(Example 8) The catalyst used in Example 5 was used in 0.1 ml.
The purification performance of trimethylamine was examined using 1 g.

The evaluation gas was trimethylamine (O ₂ 20%
/ N ₂ balance) 5L evaluation method is odor analysis odor bag containing catalyst sample and evaluation gas (Omi Odoair Service)
Is allowed to stand at room temperature, and after 1 hour, 3 hours, and 24 hours, the concentration of residual trimethylamine in the bag is measured with an FTD gas chromatograph (manufactured by Shimadzu: GC-14A), and the time-dependent change in the concentration of trimethylamine is determined. Was.

Comparative Example 8 Evaluation was performed in the same manner as in Example 8 except that the activated carbon used in Comparative Example 5 was used instead of the purification catalyst. FIG. 6 shows the results.

As shown in FIG. 6, it can be seen that the catalyst of Example 8 has higher purification performance of trimethylamine than the activated carbon of Comparative Example 8. Therefore, the catalyst of Example 8 shows that odorous substances such as trimethylamine can be purified at room temperature.

Example 9 A cerium oxide powder was impregnated with a predetermined amount of an aqueous solution of a Pt salt (“Platinum P Salt” manufactured by Tanaka Kikinzoku Co., Ltd.), and evaporated to dryness. After firing for a period of time, Pt was supported. At this time, the amount of Pt carried in the cerium oxide powder was 1 g per 150 g of the cerium oxide powder. Thereafter, the catalyst was treated at 500 ° C. for 1 hour in a nitrogen gas containing 5% hydrogen gas to obtain a catalyst of Example 9. At this time, the ratio of Ce and O in the catalyst powder was 1: 1.9 from X-ray diffraction and elemental analysis.

Example 10 A catalyst powder of Example 10 was prepared in the same manner as in Example 9 except that the ratio of Ce and O was adjusted to be 1: 1.8.

(Example 11) Example 1 was repeated in the same manner as in Example 9 except that the ratio of Ce and O was adjusted to 1: 1.7.
A catalyst powder of No. 1 was prepared.

(Example 12) The ratio of Ce to O was 1: 1.65.
A catalyst powder of Example 12 was prepared in the same manner as in Example 9, except that the catalyst powder was prepared as follows.

Example 13 A catalyst powder of Example 13 was prepared in the same manner as in Example 9 except that the ratio of Ce and O was adjusted to be 1: 1.6.

(Example 14) Ce to O ratio of 1: 1.55
A catalyst powder of Example 14 was prepared in the same manner as in Example 9, except that the catalyst powder was prepared as follows.

Example 15 A catalyst powder of Example 15 was prepared in the same manner as in Example 9 except that the ratio of Ce and O was adjusted to 1: 1.5.

(Example 16) Except that the supported amount of Pt was adjusted to be 0.1 g per 150 g of cerium oxide, and the ratio of Ce to O was adjusted to be 1: 1.8. In the same manner as in Example 9, a catalyst powder of Example 16 was prepared.

Example 17 A catalyst powder of Example 17 was prepared in the same manner as in Example 16, except that the amount of Pt supported was adjusted to 0.5 g per 150 g of cerium oxide.

Example 18 A catalyst powder of Example 18 was prepared in the same manner as in Example 16 except that the amount of Pt supported was adjusted to 5 g per 150 g of cerium oxide.

Example 19 A catalyst powder of Example 19 was prepared in the same manner as in Example 16 except that the amount of Pt supported was adjusted to 15 g per 150 g of cerium oxide.

Example 20 A catalyst powder of Example 20 was prepared in the same manner as in Example 16, except that the amount of Pt carried was 17 g per 150 g of cerium oxide.

Example 21 A catalyst powder of Example 21 was prepared in the same manner as in Example 16, except that the amount of Pt supported was adjusted to 0.01 g per 150 g of cerium oxide.

(Example 22) A catalyst powder of Example 22 was prepared in the same manner as in Example 16 except that Pd was used instead of Pt so as to be 1 g per 150 g of cerium oxide.

Example 23 A catalyst powder of Example 23 was prepared in the same manner as in Example 16 except that Rh was adjusted to 1 g with respect to 150 g of cerium oxide instead of Pt.

Example 24 A catalyst powder of Example 24 was prepared in the same manner as in Example 16 except that Au was adjusted to 1 g with respect to 150 g of cerium oxide instead of Pt.

Example 25 A catalyst powder of Example 25 was prepared in the same manner as in Example 16 except that Ru was prepared in place of Pt so as to be 1 g per 150 g of cerium oxide.

(Example 26) Pt was converted to cerium oxide 15
A catalyst powder of Example 26 was prepared in the same manner as in Example 16, except that 1 g was prepared for 0 g and 1 g of Pd was prepared for 150 g of cerium oxide.

(Comparative Example 9) The ratio of Ce to O is 1: 2.0
A catalyst powder of Comparative Example 9 was produced in the same manner as in Example 9 except that the oxide was prepared so as to be as follows, that is, the reduction treatment was not performed.

Comparative Example 10 A catalyst powder of Comparative Example 10 was prepared using activated carbon (BFG-3 manufactured by Cataler Co., Ltd.) in place of the Pt-supported cerium oxide powder.

(Evaluation of catalyst) As an evaluation gas, formaldehyde which is an odor substance: 100 ppb, oxygen: 20%,
Nitrogen: Using a balanced gas, a 5-liter odor bag (manufactured by Omi Auto Air Service) containing 0.5 g of each of the above samples and an evaluation gas, and a circulation pump at room temperature at a circulation rate of 10 liters / minute at room temperature. The evaluation gas was circulated.
The space velocity was 600,000 h- ¹ . In the above measurement, a filter was placed in front of the gas pump so that the sample did not scatter from the odor bag. Twenty minutes after circulation, the purification rate of formaldehyde in the evaluation gas was measured. For the measurement, the formaldehyde concentration was analyzed using a formaldehyde analyzer by an enzyme-chemiluminescence method, and the formaldehyde purification rate was determined by the following equation.

Formaldehyde purification rate (%) = {(formaldehyde concentration in smell bag before reaction−sample coexistence 20)
The result is shown in Table 2. The formaldehyde concentration in the odor bag before the reaction) / the formaldehyde concentration in the odor bag before the reaction} × 100.

[0126]

[Table 2]

As shown in Table 2, each of the catalysts of Examples 9 to 15 supported the same amount of noble metal in the formaldehyde purification rate.
It shows that the purification rate is higher than that of Comparative Example 9 which is not subjected to the reduction treatment and that it is higher than that of the activated carbon of Comparative Example 10, indicating that it is effective for purification of formaldehyde at room temperature. In particular, the catalyst of Example 13 has a high purification rate of 88%, and the purification rate is higher when the degree of oxygen deficiency is high than when the amount of noble metal is large. Therefore, it is suggested that the larger the oxygen deficiency state of the oxide, the more effective the catalyst purification performance is.

Examples 16 to 21 show that there is an optimum amount of Pt supported, and the amount of Pt supported and used on cerium oxide is 0.1 g per 150 g of cerium oxide.
By containing from 01 g to 20 g, more preferably from 0.5 g to 5 g, harmful substances can be purified at room temperature.
Examples 22 to 26 show that supported noble metals other than Pt are also effective. (Example 27) An aqueous solution of dinitrodiammineplatinum was added to iron oxide powder so that the ratio of platinum was 2 g to 200 g of iron oxide, and the solution was stirred and heated to evaporate the solution to dryness, whereby iron oxide supporting a platinum salt was added. A powder was obtained. This powder was calcined at 500 ° C. for 3 hours in the atmosphere to obtain a platinum-supported iron oxide catalyst. This catalyst is used in a nitrogen stream containing 1% of CO before the measurement of the oxidation activity of carbon monoxide at room temperature.
An activation treatment for introducing oxygen vacancies into the catalyst was performed by performing a reduction treatment at 0 ° C. for 15 minutes. (Example 28) A platinum-supported manganese oxide catalyst prepared in the same manner as in Example 27 except that manganese oxide powder was used instead of iron oxide powder. (Comparative Example 11) A platinum-supported silica catalyst was prepared in the same manner as in Example 27 except that silica was used instead of the iron oxide powder. (Comparative Example 12) A platinum-supported zirconia catalyst was prepared in the same manner as in Example 27 except that zirconia was used instead of iron oxide powder. (Comparative Example 13) A platinum-supported alumina catalyst was prepared in the same manner as in Example 27 except that alumina was used instead of iron oxide powder.

The catalysts prepared above (Examples 27 to 2)
8, the evaluation of the purification performance of Comparative Examples 11 to 13) was performed by using a 20 g catalyst at a gas flow rate of 5 L / min, a CO concentration of 250 ppm,
The test was performed under the condition of an oxygen concentration of 20%. Table 3 shows the results.

[0130]

[Table 3]

The iron oxide catalyst of Example 27 and the acid of Example 28
Of the relationship between the oxygen deficiency rate and the CO conversion rate of the manganese oxide catalyst
The rough is shown in FIG. 7 and FIG. In Example 27, the catalyst 20
g and a gas flow rate of 5 L / min.
The catalyst activity was measured under the conditions of a medium volume of 5 g and a gas flow rate of 10 L / min.
Specified. Note that the evaluation gas composition CO₂250 ppm, O
₂The condition of 20% was common. Both have an oxygen deficiency rate of 1
A peak of CO conversion is observed around 0%,
The loss indicates that CO can be purified. Figure
From Fig. 7, in the case of the iron oxide catalyst, the oxygen deficiency rate is in the range of 2 to 11%.
In the case of a manganese oxide catalyst as shown in FIG.
It can be seen that the defect rate is preferably in the range of 5 to 18%. This
Here, the oxygen deficiency rate of iron oxide and oxygen deficiency rate of manganese oxide
Is Fe ₂O₃, MnO₂To oxygen content
The ratio of the amount of oxygen lost is shown.

As shown in Table 3, the catalyst containing the oxide of the present invention has the ability to purify CO at ordinary temperature.

(Example 29) A slurry was prepared by mixing cerium oxide with an aqueous solution of zirconium nitrate so that the molar ratio of Ce / Zr was 10/1. 13
After drying at 0 ° C. for 3 hours, baking was performed at 500 ° C. in the air for 3 hours.
CeO ₂ · ZrO ₂ powder 150 thus obtained
g was loaded with 2 g of Pt. This powder is 1-2m
It was formed into a pellet having a diameter of m. After that, reduction treatment was performed in nitrogen gas containing 5% hydrogen at 500 ° C. for 1 hour.
29 catalyst samples were used.

1 g of this catalyst sample was evaluated for its purification performance against ethylene gas.

The evaluation gas was ethylene (initial concentration: 200 p
pm) 5% oxygen 20% nitrogen balance.

The evaluation method was as follows. A sample and an odor analysis bag (Omi Auto Air Service) containing an evaluation gas were placed at 10 ° C.
, And after 1 hour, 2 hours, 3 hours, and 24 hours, the ethylene concentration was measured with a FID gas chromatograph (HCM-1B, manufactured by Shimadzu Corporation) to determine the change over time in the ethylene concentration. FIG. 9 shows the results.

When the catalyst of the present invention was not used as a comparative example (Comparative Example 14), when the activated carbon powder (BFC-3 manufactured by Cataler) was used in the same ratio as in Example 29 instead of the catalyst of Example 29 (Comparative Example 15) was similarly evaluated.

As shown in FIG. 9, the present embodiment 29 is a comparative example 1.
It can be seen that the ability to remove ethylene is higher than that of the activated carbon of No. 5. (Example 30) Broccoli, which is liable to deteriorate in quality due to yellowing or flower buds blossoming during distribution, was selected as fresh food, and freshness retention was examined from the degree of yellowing of flower buds. The degree of yellowing is a sensory evaluation by visual observation. The degree of yellowing = 0 is no change in yellowing, the degree of yellowing = 1 is a little change in yellowing, the degree of yellowing = 2 is a considerable change in yellowing, and the degree of yellowing = 3. All tests were performed based on yellowing criteria.

A commercially available broccoli bunch (variety:
Tangling) was placed in a 1-liter odor analysis sampling bag (GL Sciences Co., Ltd., material: fluororesin, film thickness 50 μm), and the catalyst used in Example 29 was enclosed and sealed with 1 g of broccoli per 1 kg. ,
One liter was introduced with care so that the catalyst in the sampling back was not scattered from the air cylinder prepared in advance.

Next, the sampling bag was placed in a thermostat at 10 ° C., and the degree of yellowing of broccoli during the sampling was periodically evaluated.

When the catalyst of the present invention was not used as a comparative example (Comparative Example 16), the same amount of activated carbon powder (BFG-3 manufactured by Cataler) was used in place of the catalyst of Example 30 as in Example 30. (Comparative Example 17) was similarly evaluated.

Table 4 shows the results.

[0143]

[Table 4]

As shown in Table 4, in Example 30, the progress of the degree of yellowing of the flower buds was slower than in Comparative Examples 16 and 17, indicating that it was effective in maintaining the freshness of broccoli. (Example 31) Apple was selected as a fresh food, and the freshness retaining effect of the catalyst of the present invention was evaluated from the discoloration of the pericarp, the hardness of the fruit, and the taste index.

Two commercially available apples (variety: Fuji)
Was placed in a 1-liter odor analysis sampling bag (aluminum, film thickness: 130 μm, manufactured by GL Sciences Inc.), and 0.5 g of the catalyst of Example 30 was enclosed per 1 kg of apple.

Next, this sampling bag was placed in a thermostat at 15 ° C. and periodically evaluated based on the discoloration of the apple peel, the hardness of the fruit, and the taste index during the sampling.

When the catalyst of Example 31 was not used as a comparative example (Comparative Example 18), activated carbon powder (BFG-3 manufactured by Cataler) was used in the same ratio as in Example 31 instead of the catalyst of Example 31. The case (Comparative Example 19) was similarly evaluated.

Fruit hardness; 1: hard, 2: slightly soft,
3: Softening food sparseness index; always bad: 0, bad: 0.5, slightly poor:
1, 5: Very good: 1.5, Very good: 2,

[0149]

[Table 5]

[0150]

[Table 6]

[0151]

[Table 7]

As shown in Tables 5 to 7, Comparative Examples 18 and 1
9, the hardness and the taste index are remarkably reduced, whereas in Example 31, the state close to the state immediately after the purchase of the apple is maintained, and it can be seen that this is effective in maintaining the freshness of the apple.

Therefore, it is shown that the room temperature purification catalyst of this embodiment 31 has the ability to remove ethylene at room temperature.

(Example 32) Grain size to 0.5 to 2 mm
Of deionized water equivalent to the amount of water absorbed by 75 g of activated carbon
Cerium nitrate hexahydrate (CeO₂75g phase in conversion
To) and Pt (NO₂) ₂(NH₃)₂(0 in Pt conversion.
After dissolving 5 g), this aqueous solution was added to 75 g of activated carbon.
Water was absorbed. The obtained activated carbon of the catalyst precursor is
Dry at 110 ° C. for 6 hours. Then a nitrogen containing 5% hydrogen
500 ° C / min.
After the temperature was raised to 0 ° C., the temperature was maintained for 1 hour. afterwards,
After cooling to room temperature, the catalyst of this example was obtained.

Example 33 Cerium nitrate hexahydrate (corresponding to 75 g in terms of CeO ₂ ) was dissolved in deionized water in an amount corresponding to the water absorption of 75 g of activated carbon sized to a particle size of 0.5 to 2 mm. After that, the aqueous solution was absorbed by 75 g of activated carbon. The activated carbon obtained as a precursor was dried at 110 ° C. for 6 hours in the air, and then dried under a nitrogen gas atmosphere containing 5% hydrogen.
After the temperature was raised to 500 ° C. at a temperature rising rate of
It was kept for one hour. Next, Pt (NO ₂ ) ₂ (NH
₃ ) Pt is supported on the activated carbon using an aqueous solution containing ₂ (corresponding to 0.5 g in terms of Pt), and up to 500 ° C. at a rate of 5 ° C./min or less under a nitrogen gas atmosphere containing 5% hydrogen. After the temperature was raised, the temperature was maintained for 1 hour. Thereafter, the mixture was cooled to room temperature to obtain a Pt / CeO ₂ / activated carbon catalyst.

Example 34 Cerium nitrate hexahydrate (corresponding to 60 g in terms of CeO ₂ ) and 75 g of powdered activated carbon
Was added to 500 g of deionized water, stirred well, and then an aqueous ammonia solution having a molar equivalent of 1.2 times the neutralization equivalent was added to obtain activated carbon as a catalyst precursor. The activated carbon of this precursor was heated to 500 ° C. at a rate of 5 ° C./min or less in a nitrogen atmosphere, and was heated for 3 hours. Pt is added to the obtained product.
(NO ₂ ) ₂ (NH ₃ ) ₂ (equivalent to 0.5 g in terms of Pt)
Pt is supported on the generated activated carbon using an aqueous solution containing
After the temperature was raised to 500 ° C. at a rate of 5 ° C./min or less in a nitrogen gas atmosphere containing 5% hydrogen, the temperature was maintained for 1 hour. The Pt-supported activated carbon obtained after cooling to room temperature was mixed and kneaded with ceria sol (15 g as CeO ₂ amount) and 68 g of deionized water, and then granulated to a particle size of 0.5 to 2 mm. The obtained pellets are dried in the air at 110 ° C. for 6 hours, and further dried under a nitrogen gas atmosphere containing 5% hydrogen.
After heating at 0 ° C. for 1 hour, the mixture was cooled to room temperature to prepare a catalyst.

Example 35 Cerium nitrate hexahydrate (equivalent to 60 g in terms of CeO ₂ ), zirconium oxynitrate dihydrate (equivalent to 9 g in terms of ZrO ₂ ), and 75 g of powdered activated carbon were deionized. A catalyst was prepared in the same manner as in Example 34, except that the mixture was added to 500 g of water, stirred well, and then an aqueous ammonia solution having a molar equivalent of 1.2 times the neutralization equivalent was added to obtain a catalyst precursor activated carbon.

Example 36 Cerium nitrate hexahydrate (equivalent to 60 g in terms of CeO ₂ ) and powdered activated carbon 75
g and further Pt (NO ₂ ) ₂ (NH ₃ ) ₂ (corresponding to 0.5 g in terms of Pt) in 500 g of deionized water, and after stirring well, an ammonia aqueous solution having a molar equivalent of 1.2 times the neutralization equivalent. Was added to obtain a catalyst precursor. This catalyst precursor was heated to 500 ° C. at a rate of 5 ° C./min or less in a nitrogen gas atmosphere containing 5% hydrogen, and was heated as it was for 3 hours. After mixing and kneading the obtained powder and 68 g of ceria sol (15 g as CeO ₂ amount) deionized water, the particle size is 0.5-2.
mm. The obtained pellet is heated at 110 ° C. in air.
For 6 hours, heated at 500 ° C. for 1 hour in a nitrogen gas atmosphere containing 5% hydrogen, and cooled to room temperature to prepare a catalyst.

(Example 37) Powdered activated carbon and Pt
(0.5 g) carrying Pt (0.5 g) / CeO ₂ (60 g) heated at 500 ° C. for 1 hour in the air, ceria sol (15 g as CeO ₂ ) and deionized water (68 g) as a binder. After mixing and kneading, 11
Dry at 0 ° C. for 6 hours. Then, the mixture was heated at 500 ° C. for 1 hour in a nitrogen gas atmosphere containing 5% hydrogen and cooled to room temperature to prepare a catalyst.

(Comparative Example 20) Activated carbon to which neither Pt nor CeO ₂ was added was used as a catalyst.

(Comparative Example 21) Equivalent to water absorption of 75 g of activated carbon
Pt (NO) in deionized water₂)₂(NH₃) ₂(P
Example except that 0.25 g (equivalent to t) was dissolved.
A Pt / activated carbon catalyst prepared in the same manner as in No. 32 was prepared.

(Comparative Example 22) Pt (0.5 g) / activated carbon (75 g) prepared by supporting 0.5 g of Pt on 75 g of activated carbon using powdered activated carbon in the same manner as in Comparative Example 21 and CeO ₂ powder ( 60 g), mixed with ceria (as 15 g) and deionized water CeO ₂ (88 g), kneaded and granulated to a particle size 0.5 to 2 mm. Further, under a nitrogen gas atmosphere containing 5% hydrogen, the mixture was heated at 500 ° C. for 1 hour and cooled to room temperature to obtain a catalyst. In this comparative example, Pt
Is supported on activated carbon. (Evaluation) FIG. 10 shows the acetaldehyde purification rate of each catalyst prepared above, and FIG. 11 shows the CO purification rate.

Odorous substance removal test (using acetaldehyde as a representative example of odorous substance) 1-pass test Catalyst amount: 2 g Gas used: acetaldehyde (20 ppm) + oxygen (2
0%) Remaining nitrogen gas Flow rate: 5 L / min, reaction temperature: room temperature Evaluation method: The removal rate of acetaldehyde one hour after the start of gas flow was evaluated as the purification rate of acetaldehyde.

CO purification test 1 pass test Amount of catalyst: 2 g Gas used: CO (250 ppm) + oxygen (20%) Remaining nitrogen gas, flow rate: 10 L / min Reaction temperature: room temperature Evaluation method: 1 hour after starting gas flow CO removal rate
It was evaluated as an O purification rate.

In Comparative Example 20 using only activated carbon, the purification rate was as low as about 30%, and Comparative Example 2 in which Pt was supported on activated carbon was used.
Even with 1, the purification rate is 50% or less. The activity of Comparative Example 22 in which Pt-supported activated carbon and CeO ₂ were blended is almost the same as that of Comparative Example 21.

On the other hand, Pt-supported CeO subjected to reduction treatment
Example 37 in which ₂ and activated carbon were blended exhibited a purification performance of about 80%, suggesting that Pt needs to be supported on CeO ₂ . In other embodiments, Pt is CeO ₂
Since it is carried on the upper side, it is considered that it shows higher purification performance than the comparative example. As a method for supporting Pt and CeO ₂ on activated carbon, as shown in Examples 32 and 33, CeO ₂ and then Pt may be supported sequentially, or both may be supported simultaneously. This is the same in Embodiment 34 and Embodiment 36.

Further, from a comparison between Example 35 and Example 34, CeO ₂ and ZrO _{2 were used} as carrier components other than activated carbon.
It can be seen that in the case of containing, the purification performance is higher than in the case of only CeO ₂ .

As described above, in the room temperature purification catalyst of the present invention, the oxide having at least a part of oxygen deficiency by the reduction treatment carries the noble metal, and therefore, the action of both the oxide and the noble metal is carried out. Environmental load substances can be removed and purified at room temperature. In particular, it is possible to purify even small amounts of harmful substances present in the air. Particularly when cerium oxide and a noble metal are contained, formaldehyde in the air can be efficiently removed at room temperature. Therefore, this normal temperature purification catalyst can reduce the load on the human body in the living environment and contribute to the improvement of the living environment.

Further, in the room temperature purification catalyst of the present invention, ethylene can be decomposed and removed in the room temperature range, so that the physiological action of the fruits and vegetables can be suppressed, the progress of ripening can be suppressed over time, and the freshness of the fruits and vegetables can be easily maintained. .

Further, since this room temperature purification catalyst is an oxidation reaction, it consumes oxygen with the decomposition of ethylene to generate carbon dioxide. Therefore, low oxygen concentration, high carbon dioxide concentration, An atmosphere having a low ethylene concentration can be formed.

[0171] In the catalyst in which cerium oxide and a noble metal in an oxygen-deficient state are supported on activated carbon, the amount of contact of the harmful substances with the noble metal and cerium oxide per unit time can be reduced because the adsorption capacity of the activated carbon is utilized. The poisoning of the catalytically active portion by the adsorbed material can be suppressed, and the purification performance can be maintained for a long time.

Next, the application of the room temperature purification catalyst of the present invention to an activated carbon filter for an air purifier will be described.
In addition, this activated carbon filter can be applied to all types of air purifiers, such as an indoor installation type, a house built-in type, and a vehicle. In the following examples, a solid solution or a composite oxide of cerium oxide and zirconium oxide (hereinafter referred to as “CeO ₂ .ZrO ₂ ”) is adopted as the oxide,
Although platinum is adopted as the noble metal, it goes without saying that other oxides and noble metals described in the specification can be used.

Example 38 Preparation of Room Temperature Purification Catalyst Cerium (III) nitrate and zirconium nitrate were mixed at a molar ratio of C
A mixed and dissolved aqueous solution was prepared so that e / Zr = 5/1, and aqueous ammonia was added dropwise while stirring the aqueous solution to neutralize and precipitate the aqueous solution. Subsequently, an aqueous solution containing an aqueous solution of hydrogen peroxide having a mole number of セ of the cerium ion contained in the aqueous solution and alkylbenzenesulfonic acid at 10% of the weight of the obtained oxide was added dropwise and stirred. The obtained slurry is dried, and coexisting ammonium nitrate is removed by evaporation and decomposition, and the oxide solid powder Ce is removed.
O ₂ · ZrO ₂ was obtained. Next, Pt (NO ₂ ) ₂ (N
Using an aqueous solution containing H ₃ ) ₂ , Pt was supported at a rate of ₂ g on 150 g of the oxide solid solution powder CeO ₂ .ZrO ₂ . _{N 2} The Pt-supported oxide solid solution containing 5% _{H 2}
After the temperature was raised to 500 ° C. in a gas at a rate of 5 ° C./min or less, the temperature was maintained for 1 hour. Thereafter, the mixture was cooled to room temperature to obtain a Pt / CeO ₂ .ZrO ₂ catalyst.

The thus obtained catalyst of Example 38 was mixed with activated carbon while changing the amount thereof, and the adsorption decomposition performance of formaldehyde was examined. The result is shown in FIG. The activated carbon filter of this embodiment is obtained by adding a catalyst and other auxiliaries (such as a binder) to a commercially available activated carbon, kneading the mixture, extruding it into a honeycomb shape, and then drying and slicing it to a predetermined thickness. It is a thing. The size of this activated carbon filter is 5
0 mm x 250 mm x thickness 8 mm, cell density is about 500
/ Inch ² . In the evaluation method, a small air purifier (fan + activated carbon filter) was put in a 50 liter (L) container, and formaldehyde gas was charged into the container at a concentration shown in the graph. Operate the air purifier (0.9m ³ / mi
n), and the CO ₂ concentration in the container was measured by gas chromatography over time. The increase in CO ₂ concentration is C
The amount of generated O ₂ was used.

From the results shown in FIG. 12, it is preferable that the blending amount of the catalyst be 3% by weight or more. More preferably 5% by weight
And more preferably 10% by weight or more. The upper limit of the amount of the catalyst is not particularly limited, but if it exceeds 30% (that is, if the amount of activated carbon is less than 70%), the excellent deodorizing ability of the activated carbon decreases, which is not preferable. In the above, auxiliaries such as binders are not included on a weight% basis. The mixing ratio of the active ingredient (activated carbon + catalyst) and the auxiliary agent is appropriately selected. For example, the active ingredient: the auxiliary agent = 100: 10 (parts by weight).

As the binder as the auxiliary agent, an organic water-soluble binder and a water-dispersed binder can be used.
Examples of such a binder include cellulose derivatives such as methylcellulose, carboxymethylcellulose, and ethylcellulose. In general, extruding materials include auxiliary agents such as binders, dispersants, and wetting agents in addition to the binders described above.

[0177] The shape of the opening of the activated carbon filter is not limited to the hexagon of the honeycomb, but may be any shape such as a polygon such as a triangle or a quadrangle, an ellipse, or a circle which does not hinder the flow of air. Can be selected.

In this embodiment, the oxide is loaded with a noble metal and then subjected to a reduction treatment to bring the oxide into an oxygen-deficient state. Then, the catalyst is mixed with the activated carbon. According to the manufacturing method of this embodiment, only one reduction process is required, so that the manufacturing process is simplified and the manufacturing cost can be reduced. Further, according to this embodiment, since the catalyst is prepared in advance and mixed with the activated carbon particles, the catalyst and the activated carbon particles can be prepared independently and arbitrarily. As a result, the amount of the activated carbon can be increased as much as possible.

(Example 39) It is preferable to add a photocatalyst to the activated carbon filter. As a result, the types of environmental load substances that can be removed and the adsorption capacity are enhanced. For example, when titanium oxide is used as the photocatalyst, the ability to adsorb tobacco odor components such as ammonia and acetic acid is enhanced.

The ammonia removing ability of the catalyst of Example 38 in which titanium oxide was used in combination with the photocatalyst at the room temperature purification catalyst was examined. The result shown in FIG. 13 was obtained. In FIG. 13, the active components (parts by weight) of the activated carbon filter are as follows. Activated carbon Room-temperature purification catalyst Titanium oxide sample 80 10 10 Sample 75 10 15 The activated carbon filter of this example is also kneaded by adding a catalyst and other auxiliaries (such as a binder) to commercially available activated carbon and extruding it into a honeycomb shape. And then dried and sliced to a predetermined thickness. The size of this activated carbon filter is 100 mm x 250 mm x 8 mm in thickness, and the cell density is about 5
00 / inch ² . The evaluation method was as follows. A small air purifier (fan + activated carbon filter) was placed in a 1 m ³ liter (L) container, and ammonia gas was introduced into the container. The air purifier was operated (2 m ³ / min), and the ammonia concentration in the container was measured with the passage of time with a gas detector tube.
From the results shown in FIG. 13, it can be seen that the sample containing a larger amount of titanium oxide has more excellent ammonia removing ability.

When the ability to remove acetic acid was examined for the case where titanium oxide was used in combination with the ordinary temperature purification catalyst as the photocatalyst in Example 38, the results shown in FIG. 14 were obtained. In FIG. 14, the active components (parts by weight) of the activated carbon filter are as follows. Activated carbon Room temperature purification catalyst Titanium oxide Sample 85 10 5 Sample 70 10 20 After extruding this activated carbon filter in the same manner as in the above example (for removing ammonia gas), the molded product was extruded.
The powder was pulverized to a particle size of 0 μm or less to obtain a sample powder. In the evaluation method, the sample powder was put in a 5 liter (L) bag, acetic acid gas was put into the bag, and the bag was allowed to stand at room temperature. Then, the acetic acid concentration remaining in the bag after 24 hours was measured by gas chromatography, and the results of FIG. 14 were obtained for the acetic acid concentration and the amount of adsorption. From the results shown in FIG. 14, it can be seen that the sample containing a larger amount of titanium oxide has more excellent acetic acid removal ability.

From the above results, it is understood that the performance of the filter is improved by adding the photocatalyst. The amount of the photocatalyst is preferably 3% by weight or more based on the active ingredient. More preferably, it is at least 5% by weight. When a photocatalyst is added, the addition amount of the room temperature purification catalyst is 3 per active component.
It is preferable that the content be not less than% by weight. More preferably, 5
%, More preferably 10% by weight or more. The upper limit of the amount of the catalyst is not particularly limited, but if it exceeds 30% (that is, if the amount of activated carbon is less than 70%), the excellent deodorizing ability of the activated carbon decreases, which is not preferable.

In addition to general-purpose titanium oxide as a photocatalyst, Cu, Zn, La, Mo, V, Sr, Ba, Ce,
At least one selected from the group consisting of oxides of Sn, Fe, W, Mg, and Al, composite oxides thereof, and sulfides such as CdS can be used. Furthermore, a so-called composite photocatalyst in which at least one of noble metals such as Pd, Pt, Au, and Ag is supported on such a photocatalyst can also be used. It is particularly preferable to use a TiO ₂ -Pd composite catalyst. Such a composite photocatalyst is disclosed in JP-A-8-2.
See, for example, Japanese Patent No. 57410. It is preferable to irradiate the titanium oxide layer with ultraviolet rays in order to oxidatively decompose the adsorbed environmental load substance. A cold cathode tube or an LED can be used as the light source. Further, the photocatalyst can be activated using sunlight. In the case of using sunlight, it is assumed that sunlight taken from the outer surface of the vehicle is applied directly or through a mirror or an optical fiber to the titanium oxide layer. It is known that, when titanium oxide is carried on a filter, the ability to adsorb activated carbon is regenerated by supplying sufficient light to the titanium oxide in a state where the ventilation is reduced or stopped (Japanese Patent Application Laid-Open No. H9-209). -25345
No. 2). Such regeneration can be applied to the filter of the present invention. That is, when the on-vehicle air conditioner is stopped, the filter is irradiated with light, so that the filter is regenerated. The filter thus regenerated is fixedly attached to an air purifier or the like, and does not need to be replaced.

Next, an example of an air purifier using the activated carbon filter of Embodiment 39 will be described. In addition, the air purifier for houses can also employ substantially the same structure. FIG. 15 shows the configuration of the air purifier 1. The air purifier 1 is generally constituted by a ventilation unit 10 and a cleaning unit 20. The ventilation unit 10 and the cleaning unit 20 are built in the casing 2. The casing 2 is composed of a housing 3 embedded in a wall and a front panel 4 exposed inside the room. A lower edge of the front panel 4 is provided with an inlet 5 for indoor air, and an upper edge thereof is provided with an outlet 6 for purified air. An intake port 7 for indoor air is also opened on the lower surface of the housing 3 on the side of the ventilation section 10, and the air taken in from this is discharged to the outside by the ventilation section 10. An exhaust port 8 for indoor air and an intake port 9 for outdoor air are opened on the back surface of the housing unit 3 on the side of the ventilation unit 10, and each communicates with the outside through ducts (not shown).

The ventilator 10 comprises an exhaust fan 11, an air supply fan 12, and a heat exchanger 13. General-purpose fans can be used for the exhaust fan 11 and the air supply fan 12, and each of them is rotated by a common motor (not shown). The exhaust fan 11 and the air supply fan 12 are partitioned by a partition 15. The air in the room passes through the intake port 7 and the heat exchanger 13 and is discharged to the outside of the room through the discharge port 8 by the exhaust fan 11. The outdoor air is taken in from the intake port 9 by the air supply fan 12 and sent to the cleaning unit 20 through the heat exchanger 13.

The heat exchanger 13 is a first layer 1 of a corrugate which connects the indoor air intake 7 and the exhaust fan 11.
3a and a second layer 13b of a corrugate for alternately communicating the outdoor air sent from the air supply fan 12 to the cleaning unit 20 side are alternately laminated. The heat exchanger 13 is formed of a material having a high thermal conductivity. Such a heat exchanger is well known, for example, as described in JP-A-5-269323.

Since the exhaust fan 11 and the air supply fan 12 are separated by the partition 15, there is no mixing of the exhausted indoor air and the sucked outdoor air. In the heat exchanger 13 as well, the indoor air and the outdoor air pass through dedicated corrugated layers 13a and 13b, respectively, and therefore do not mix here. The heat exchanger 13 is heated by the room air that discharges the sucked outdoor air, thereby preventing the room temperature from suddenly changing.

The air purifier 20 comprises a lower dust collector 21, an upper deodorizer 27 and a cross flow fan 33. The dust collector 21 includes an ionization electrode 23 and a dust collection electrode 25. When a high voltage is applied between the two, corona discharge starts at the ionization electrode 23. When the ions generated by the discharge come into contact with dust in the air, the dust is positively charged. Then, the positively charged dust is sucked by the dust collecting electrode 25. In addition, ion wind is generated by corona discharge. Therefore, when the indoor air is less contaminated, the cross flow fan can be stopped and the indoor air can be circulated only by this ion wind.

In the example, three discharge wires were used as the ionization electrode 23. As the dust collecting electrode 25, a negative conductive film and a film obtained by winding a positive conductive film coated with an insulating resin such as polypropylene were used. The dust sucked by the dust collecting electrode 25 adheres to the electrode film and does not separate. Ionization electrode 23
And the voltage applied to the dust collecting electrode 25 are 5.65, respectively.
KV and 2.4 KV. The dust collecting device 21 has a known configuration. See, for example, JP-A-9-19647.

The deodorizing device 27 comprises two ultraviolet lamps 29 and a pair of activated carbon filters 30 of the embodiment sandwiching the ultraviolet lamps 29 vertically.
Consists of 31.

In this embodiment, an activated carbon filter 30 is interposed between the dust collecting electrode 25 and the ultraviolet lamp 29 so that ultraviolet rays do not irradiate the dust collecting electrode 25. Thereby, deterioration of the dust collection electrode 25 can be further reduced.

Reference numerals 35, 36 and 37 in the figure are an odor sensor, a dust sensor and an optical sensor, respectively. Reference numeral 38 denotes an alarm buzzer. Reference numeral 40 denotes a remote controller using infrared rays, and reference numeral 39 denotes a light receiver for receiving infrared rays.

The present invention is not limited to the above embodiments and examples. Various modifications are included in the present invention without departing from the scope of the claims and within the scope of those skilled in the art.

The following items are disclosed. 1. Precious oxides with oxygen vacancies introduced by reduction
Room temperature purification catalyst supporting metal. 2 The oxide is a transition metal oxide or a rare earth oxide.
2. The room temperature purification catalyst according to 1, which is at least one selected from. 3. The transition metal oxide is zirconium, iron, manganese,
, Cobalt, nickel, copper, chromium, molybdenum,
At least one selected from oxides of
Rare earth oxides include cerium, yttrium, neodymium,
Praseodymium, less selected from samarium oxide
3. The room temperature purification catalyst according to 2, which is a kind of both. 4. Cerium oxide and zirconate as the oxide
The cerium oxide and the zirconia.
Oxide is mainly converted to cerium oxide by reduction treatment.
1 or 3 at least partially present in the state of oxygen deficiency
The catalyst for purification at room temperature according to the above. 5. Has the function of purifying environmentally hazardous substances in the air at normal temperature
5. The room temperature purification catalyst according to claim 4, wherein 6. The normal temperature purification according to 5, wherein the environmentally hazardous substance is an odorous substance
catalyst. 7. The room temperature purification according to 5, wherein the environmentally hazardous substance is carbon monoxide.
Catalyst. 8 The environmentally hazardous substance is nitrogen oxides,
Catalyst. 9. Room temperature purification according to item 5, wherein the environmentally hazardous substance is ethylene
catalyst. 10. The cerium oxide and the zirconium oxide
Is from 4 to 9 forming a solid solution or a composite oxide.
A room temperature purification catalyst according to any one of the above. 11 Titanium oxide, alumina, silica, zeolite,
-Selected from gelite, sepiolite, and activated carbon
4 to 9 supported on at least one carrier
A room temperature purification catalyst according to any of the above. 12. The method according to 1, wherein the oxide contains cerium oxide.
Room temperature purification catalyst. 13 The cerium oxide is at least
Some are present in a state of oxygen deficiency.
1 that has the function of purifying carbon monoxide at normal temperature
3. The room temperature purification catalyst according to 2. 14 After the reduction treatment, the cerium oxide
Described in 13, which is an oxygen deficiency state of 1.5 ≦ n <2.
Room temperature purification catalyst. 15 After the reduction treatment, the cerium oxide
And is in a state of oxygen deficiency of 1.5 ≦ n ≦ 1.8.
The catalyst for purification at room temperature according to the above. 16 Formaldehyde, trimethylamine,
Environmental load such as chill mercaptan and acetaldehyde
The normal temperature according to 14, wherein at least one of the qualities is purified at normal temperature
Purification catalyst. 17 As carrier, alumina, silica, zeolite, acid
Titanium chloride, cordierite, sepiolite, and activity
Characterized by using at least one selected from charcoal
A room temperature purification catalyst according to any one of 12 to 16. 18. The purification reaction of the odorous substance is a purification reaction temperature of 25 ° C.
Degree, space velocity 600000h ^-1Purification reaction under different conditions
6. Purification rate after 20 minutes after the start is 50% or more
Room temperature purification catalyst. 19. The purification reaction of carbon monoxide is a purification reaction at 25 ° C.
At temperature, space velocity 120,000h^-1In the conditions of
That the purification rate 30 minutes after the start of the chemical reaction is 40% or more
The room temperature purification catalyst according to 7, which is characterized in that: 20 The cerium oxide and zirconium oxide
Oxide specific surface area after reduction treatment at 500 ° C for 1 hour
Is 50m^Two5. The room temperature purification catalyst according to 4, which is not less than / g. 21 The cerium oxide and zirconium oxide
Oxide has a specific surface area after reduction treatment at 800 ° C. for 1 hour.
Is 15m^Two20. The room temperature purification catalyst according to 20, which is not less than / g. 22 The precious metal described in 1 whose particle diameter is 5 nm or less.
Room temperature purification catalyst. 23 The noble metal has a particle diameter of 1 nm or less.
The normal temperature purification catalyst according to the above. 24 The reduction treatment is performed at a treatment temperature of 100 ° C to 800 ° C.
The room temperature purification catalyst according to 1, which is: 25 The reduction treatment is performed at a treatment temperature of 200 ° C to 600 ° C.
25. The room temperature purification catalyst according to 24. 26 The oxygen deficiency in the surface layer of the cerium oxide particles is
15. The room temperature purification catalyst according to 14, wherein 1.5 ≦ n ≦ 1.8. 27 In addition, it contains activated carbon,
And cerium oxide, which is partially oxygen-deficient
4. The room temperature purification catalyst according to 1 or 3, including: 28 at least a part of the noble metal is the ceric acid
28. The room temperature purification catalyst according to 27, supported on a compound. 291 The room temperature purification catalyst according to any one of 1 to 4, is an environmentally hazardous substance.
Carbon monoxide, nitrogen oxides, ethylene, aldehydes,
Min, mercaptan, fatty acids, odorants, aromatic carbonization
The ring is brought into contact with air containing at least one of hydrogens.
Room temperature purification characterized by purifying environmental load substances at room temperature
How to use the conversion catalyst.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE FIGURES FIG. 1: 24 hours after 1, 2, and 3 hours of each sample of Example 5, Comparative Examples 4 and 5 at an acetaldehyde concentration of 36 ppm.
It is the graph which compared the purification rate after 96 hours and 96 hours.

FIG. 2: After 1, 2, and 3 hours of each sample of Example 5, Comparative Examples 4 and 5 at an acetaldehyde concentration of 72 ppm, 24
It is the graph which compared the purification rate after 96 hours and 96 hours.

FIG. 3 shows that each of the samples of Example 5, Comparative Examples 4 and 5 at acetaldehyde concentration of 270 ppm
It is the graph which compared the purification rate after 4 hours and 96 hours.

FIG. 4 is a graph comparing the removal rates of formaldehyde between the catalyst of Example 6 and activated carbon.

FIG. 5 is a graph comparing the removal rate of methyl mercaptan between the catalyst of Example 7 and activated carbon.

FIG. 6 is a graph comparing the removal rates of trimethylamine between the catalyst of Example 8 and activated carbon.

FIG. 7 is a graph showing the relationship between the degree of oxygen deficiency of iron oxide and the CO conversion rate in Example 27.

FIG. 8 is a graph showing the relationship between the degree of oxygen deficiency of manganese oxide and the CO conversion rate in Example 28.

FIG. 9 is a graph showing the change over time in ethylene concentration with the use of a room temperature purification catalyst, a room temperature purification catalyst, and activated carbon of Example 29.

FIG. 10 shows Examples 32-37 and Comparative Examples 20-22.
4 is a bar graph showing the purification rate of acetaldehyde in Example 1.

FIG. 11 shows Examples 32 to 37 and Comparative Examples 20 to 22.
4 is a bar graph showing a purification rate of carbon monoxide.

FIG. 12 is a graph showing the relationship between the blending amount of a room-temperature purification catalyst of Example 38 in an activated carbon filter and formaldehyde decomposition performance.

FIG. 13 is a graph showing the ammonia gas adsorption performance of the activated carbon filter of Example 39.

FIG. 14 is a graph showing the acetic acid adsorption ability of the activated carbon filter (powder type) of Example 39.

FIG. 15 shows a configuration of an air purifier using the activated carbon filter of Embodiment 39.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01J 23/656 B01J 35/02 ZABJ 23/66 37/16 23/89 B01D 53/36 H 35/02 ZAB J37 / 16 B01J 23/56 301A 23/64 104A (72) Inventor Akira Kamei 2-19-12 Sotokanda, Chiyoda-ku, Tokyo Inside Equos Research Co., Ltd. (72) Inventor Masako Kondo Chiyoda-ku, Tokyo 2-19-19 Sotokanda Inside Equos Research Co., Ltd. (72) Inventor Kenichiro Suzuki 41-41, Chuku-Yokomichi, Oji, Nagakute-cho, Aichi-gun, Aichi Prefecture 1 Toyota Central Research Laboratory Co., Ltd. (72) Inventor: Ji Sasaki 41, Chukku-Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside Toyota Central Research Laboratory Co., Ltd. (72) Inventor Hideo Sobukawa Nagakute-cho, Aichi-gun, Aichi No. 41, Chochu-Yokomichi, Toyota Central Research Laboratory Co., Ltd. (72) Inventor Minoru Tanabe Minato 41, Nagakute-cho, Aichi-gun, Aichi Prefecture, Japan No. 41, Toyota Chuo Research Institute, Inc. (72) Inventor Akira Morikawa No. 41, Chuchu-ji, Yokomichi, Nagakute-cho, Aichi-gun, Aichi F-term in Toyota Central R & D Laboratories Co., Ltd. EA01 EA04 4G066 AA02B AA05B AA12B AA23B CA02 CA51 CA52 DA03 FA12 FA22 FA37 4G069 AA03 AA08 BA04A BA04B BA08A BA08B BA48A BB02A BB02B BB04A BB04B BB06A BB06B BC31A BC33A BC33B BC38A BC40A BC41A BC43A BC43B BC44A BC50A BC51A BC51B BC55A BC58A BC59A BC62A BC62B BC66A BC66B BC67A BC68A BC69A BC70A BC71A BC71B BC72A BC72B BC74A BC75A BC75B CA17 EA18 EA19 EB12Y EB14Y EC02Y FA01 FB43 FB44 FB67 FC08

Claims (12)

[Claims] 1. An active ingredient having the following composition, a normal temperature purification catalyst: 3% by weight or more, a photocatalyst: 3% by weight or more, and an activated carbon: 70% by weight or more. An activated carbon filter characterized in that a noble metal is carried on an oxide. 2. The activated carbon according to claim 1, wherein the composition of the active component is room temperature purification catalyst: approximately 10% by weight, photocatalyst: approximately 10% by weight, and activated carbon: approximately 80% by weight. filter. 3. The activated carbon filter according to claim 1, wherein the oxide includes cerium oxide and zirconium oxide, and the noble metal includes platinum. 4. The activated carbon filter according to claim 1, wherein the activated carbon filter has a honeycomb shape. 5. An active ingredient having the following composition, a normal-temperature purification catalyst: 3 to 30% by weight, activated carbon: 70 to 97% by weight, and the normal-temperature purification catalyst converts a noble metal into an oxide into which oxygen vacancies have been introduced by a reduction treatment. An activated carbon filter characterized by being carried. 6. The activated carbon filter according to claim 5, wherein the composition of the active component is: room temperature purification catalyst: approximately 10% by weight; activated carbon: approximately 90% by weight. 7. The activated carbon filter according to claim 5, wherein the oxide includes cerium oxide and zirconium oxide, and the noble metal includes platinum. 8. The activated carbon filter according to claim 5, which has a honeycomb shape. 9. a step of supporting an oxide with a noble metal and subjecting the oxide to a reduction treatment to generate oxygen deficiency in the oxide; and a step of mixing the oxide-noble metal catalyst having the oxygen deficiency in activated carbon. A method for producing an activated carbon filter having: 10. The method according to claim 9, wherein the oxide includes cerium oxide and zirconium oxide, and the noble metal includes platinum. 11. The method for producing an activated carbon filter according to claim 9, further comprising a step of blending a photocatalyst into said activated carbon. 12. An air purifier provided with the activated carbon filter according to claim 1.