JP2018134614A - Organic gas reducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel technology in which, when oxidizing an organic gas in a gas to be treated with an oxidation catalyst, the activity of the catalyst can further be maintained.SOLUTION: There is provided an organic gas reducing device for reducing an organic gas in a gas to be treated, characterized in comprising: a member having an air permeability and in which an oxidation catalyst part having a mesopore and an oxidation catalyst particle containing one or two or more substances selected from the group consisting of simple substance of platinum, palladium, and oxides thereof supported on the mesopore, is disposed on the surface thereof; and a heating part for heating the oxidation catalyst part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for oxidizing an organic gas component such as ethylene in a gas to be treated.

Since exhaust gas generated from internal combustion engines such as automobiles and factories contains trace amounts of harmful components such as carbon monoxide, they are released into the atmosphere after they are removed using removal means. In addition, in a closed storage room or the like, a trace amount of malodorous substances may be produced and a mold odor may be generated, and various removal means are applied.
In addition, agricultural products release ethylene having a ripening action, and the aging of the product progresses. Therefore, keeping the temperature and humidity constant and reducing the ethylene gas concentration are said to be effective for maintaining the freshness for a long time.

  Methods for removing organic trace components in the atmosphere include adsorption on an adsorbent such as activated carbon, radicals by a plasma generator, and decomposition and removal methods using active species such as ozone. However, the treatment method using active species such as plasma is difficult to use in the storage of agricultural crops due to concerns about apparent changes such as decolorization, and has limited applications. In the adsorption treatment with an adsorbent, the adsorbent has an upper limit on the amount of organic gas adsorbed, and the adsorbent must be periodically replaced or regenerated. Therefore, a deodorizing filter that can be used repeatedly by performing performance recovery processing by heating is disclosed (Patent Document 1).

  In the method of decomposing and removing organic components, in addition to the method of using the physically generated active species as in the plasma method described above, a method of oxidizing and removing using a catalyst is widely used and applied to a freshness maintaining device. (Patent Document 2). In order to increase the contact area of an oxidation catalyst, a structure in which an active substance (catalyst particles) is supported on a carrier that is inorganic particles is used (Patent Documents 2 and 3). In addition, an oxidation catalyst (Patent Document 6) supported on an inorganic porous carrier and a method of treating a volatile organic compound with a porous membrane of an active substance are disclosed (Patent Document 7). Furthermore, a catalyst body in which catalyst particles are supported in the pores of an inorganic mesoporous carrier having cylindrical mesopores has been developed, and a catalyst body or active substance in which catalyst particles are supported on the outer surface of the inorganic particles is porous. Compared with the converted membrane, a catalyst body having a very wide specific surface area and high activity is obtained (Patent Documents 4 and 5).

Japanese Patent Laying-Open No. 2015-023968 Japanese Patent Laid-Open No. 2006-090088 Japanese Patent Laid-Open No. 2003-080077 JP 2004-283770 A JP 2007-326094 A JP 2011-206672 A JP 2006-326530 A

However, the catalyst body in which the oxidation catalyst particles are supported on the above-described cylindrical mesoporous support has a problem that although the initial catalytic activity is high, the catalytic activity decreases with use. The cause is not clearly understood, but the contact between the catalyst particles and the gas to be treated is inhibited by the adsorption of atmospheric moisture and water generated by oxidation reaction into the pores, and decomposition reaction of harmful components May not proceed, or the pores are sealed with adsorbed water, and the flow of the gas to be treated into the pores itself may be hindered.
An object of the present invention is to provide a novel technique capable of sustaining the activity of an organic gas in a gas to be treated with an oxidation catalyst.

The gist of the present invention is as follows.
[1] An organic gas reducing device for reducing organic gas in a gas to be treated,
Oxidation catalyst particles having air permeability and having mesopores on the surface thereof and containing one or more substances selected from the group consisting of platinum and palladium supported on the mesopores and oxides thereof. A member in which an oxidation catalyst part is disposed;
An organic gas reduction device comprising: a heating unit that heats the oxidation catalyst unit.
[2] The organic gas reduction device according to [1], wherein the heating unit heats the oxidation catalyst unit to 80 ° C. or higher.
[3] The organic gas reduction device according to [1] or [2], wherein the heating unit operates intermittently.
[4] The organic gas reducing device according to any one of [1] to [3], wherein the organic gas is ethylene.
[5] The oxidation catalyst portion has a membranous support having mesopores, and the oxidation catalyst particles are supported in mesopores of the membranous support. [1] to [4] The organic gas reduction apparatus as described in any one of these.
[6] The organic gas reduction device according to [5], wherein the film-like support has a thickness of 50 nm to 1000 nm.
[7] The organic gas reduction device according to [5] or [6], wherein the film-like support is made of SiO ₂ .
[8] The organic gas reduction device according to any one of [5] to [7], wherein an average pore diameter of the mesopores measured by a BET method is 2 nm or more and 10 nm or less.
[9] The organic gas reduction device according to any one of [5] to [8], wherein an average particle diameter of the oxidation catalyst particles is 1 nm or more and 10 nm or less.
[10] The organic gas reduction device according to any one of [1] to [9], further including a gas supply unit that supplies a gas to be processed to the oxidation catalyst body.
[11] The gas supply unit has a blowing mechanism for blowing untreated gas to the oxidation catalyst unit, and a space velocity of blowing by the blowing mechanism is 10,000 / h or more and 150,000 / h or less. The organic gas reducing device according to [10].
[12] The member having an oxidation catalyst part further includes a member carrying a compound having at least one of antibacterial, antifungal and antiviral properties on the upstream side in the air flow direction [10] Or the organic gas reduction apparatus as described in [11].

  ADVANTAGE OF THE INVENTION According to this invention, when oxidizing the organic gas in to-be-processed gas with an oxidation catalyst, the novel technique which can maintain the activity of the catalyst more can be provided.

It is a figure which shows the outline | summary of 1 aspect of the organic gas reduction apparatus of this invention. It is a figure which shows the outline | summary of 1 aspect of the member which has the film-form support body by which the oxidation catalyst particle with which the organic gas reduction apparatus of this invention is equipped was carry | supported. It is a figure which shows the outline | summary of the other aspect of the member which has the film-form support body by which the oxidation catalyst particle with which the organic gas reduction apparatus of this invention is equipped was carry | supported.

Hereinafter, one embodiment of the present invention will be described in detail.
FIG. 1 is a diagram showing an outline of the organic gas reduction device of the present embodiment. 2 and 3 are oxidation catalyst particles containing one or more substances selected from the group consisting of platinum, palladium alone and oxides according to the present embodiment (hereinafter sometimes simply referred to as oxidation catalyst particles). It is a figure which shows the outline | summary of the member which has a film-like support body with which was supported. In the drawing, solid arrows indicate the direction of air movement, and broken arrows indicate the diffusion of air in the oxidation catalyst layer 33.
The organic gas reduction device 100 of the present embodiment is a device that can be used to oxidize an organic gas in a gas to be treated such as the atmosphere to provide a good atmospheric state for growing fruits and vegetables, for example. The organic gas reduction device 100 according to the present embodiment includes a member 30 having an air permeability, a member 30 on which an oxidation catalyst portion 33 having mesopores and oxidation catalyst particles carried on the mesopores is disposed, and a membrane The gas supply part 10 which supplies to-be-processed gas to a cylindrical support body, and the heating part 36 which heats an oxidation catalyst part are provided. By heating the oxidation catalyst unit by the heating unit 36, even when the function of oxidizing the organic gas in the oxidation catalyst unit is lowered due to the influence of moisture, the function can be regenerated. As a result, it can contribute to sustaining the activity of the catalyst.

  Further, in the present embodiment, the oxidation catalyst unit 33 includes a porous membrane-like support 34 having mesopore diameter pores (mesopores) through which gas can flow, and the membrane-like support 34. In the mesopores, oxidation catalyst particles are supported (the membrane-like support on which the oxidation catalyst particles are supported is hereinafter simply referred to as an oxidation catalyst layer). The gas to be treated supplied from the gas supply unit 10 diffuses and penetrates into the oxidation catalyst layer 33, and the organic gas component contained is oxidized and removed by the oxidation catalyst particles in the oxidation catalyst layer 33.

First, the oxidation catalyst layer 33 will be described.
In order to maintain the shape of the oxidation catalyst layer 33, the oxidation catalyst layer 33 is formed into a film shape on the surface of the ventilation portion 35 of the base material 31 that can be ventilated, such as a filter shape or a mesh shape. The base material 31 may be a plate-like, sheet-like, or porous block body as long as it has a structure that allows gas to pass therethrough. As a porous block body, a member having a honeycomb-shaped void is preferable because it has a large surface area and a good air permeability.

  Since the oxidation catalyst layer 33 of the present embodiment is in the form of a film, it does not take an agglomerated form like a powder. Therefore, the distance from the mesopores where the oxidation catalyst particles are present to the gas flow of the gas to be treated is It is shorter than other shapes of mesoporous catalyst bodies. Therefore, when moisture in the gas is adsorbed in the mesopores of the oxidation catalyst layer 33 of the present embodiment, a concentration gradient to the gas flow to be treated is generated, and the re-diffusion of the adsorbed water to the air flow proceeds. As a result There is an effect that adsorbed water is suppressed to a constant amount. On the other hand, the conventional powdery mesoporous catalyst body has a relatively long distance from the mesopores inside the powder to the air flow, and is particularly difficult to desorb moisture adsorbed inside the powder. It is assumed that the catalytic activity of the oxidation catalyst in the pores is reduced. Furthermore, the oxidation catalyst layer 33 of the present embodiment is preferable because it can efficiently desorb moisture adsorbed by the heat transmitted to the inside of the mesopores when the oxidation catalyst layer 33 is heated by the heating unit 38 described later.

  The film thickness of the oxidation catalyst layer 33 formed on the substrate 31 of the present embodiment is desirably 50 nm or more and 1000 nm or less. If the thickness is less than 50 nm, the absolute amount of the oxidation catalyst is reduced, so that it is difficult to sufficiently oxidize the organic gas component in the gas to be treated as compared with the case where the oxidation catalyst is within the range. If it is larger than 1000 nm, the moisture adsorbed in the mesopores present at a position away from the gas to be treated becomes difficult to be re-released, the amount of moisture adsorbed in the pores increases, and the action of the oxidation catalyst particles is inhibited. The catalyst efficiency of the oxidation catalyst layer is reduced as compared with the case where the value is within the range. The film thickness of the oxidation catalyst layer 33 of the present embodiment can be measured by observing the cross section of the film with a TEM and measuring the size of the cross-sectional image.

  The oxidation catalyst layer 33 of the present embodiment can treat organic gas, which is an organic component in the gas to be treated, into carbon dioxide, water, or the like by an oxidation reaction and discharge it into the atmosphere. Gases that can be treated in the oxidation catalyst layer 33 of the present embodiment are not particularly limited. However, compounds emitted from plants such as agricultural products and flower buds, automobile interior materials, residential building materials / interior materials, home appliance housings, Substances that volatilize from materials such as members and substances that volatilize from organic solvents such as paints, adhesives, and cleaning agents. Specifically, hydrocarbons such as methane, ethane, propane, butane, ethylene, propylene, isoprene, benzene, xylene, toluene, ethylbenzene, styrene, α-farnesene, β-farnesene, methanol, ethanol, propane-1- All, butan-1-ol, pentan-1-ol, hexane-1-ol, heptan-1-ol, octan-1-ol, trans-2-hexenol, cis-2-hexenol, trans-3-hexenol, Alcohols such as cis-3-hexenol, linalool, benzyl alcohol, formaldehyde, acetaldehyde, propionaldehyde, butanal, pentanal, nonanal, benzaldehyde, hexanal, trans-2-hexenal, cis-2-hexa Aldehydes such as nal, trans-2-octenal, trans-2-nonenal, cis-2-nonenal, trans, cis-2,6-nonadienal, trans, cis-2,4-decadienal, acetone, ethylmethyl Ketones such as ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, acetophenone, methyl formate, ethyl acetate, pentyl acetate, isopentyl acetate, octyl acetate, hexyl acetate, benzyl acetate, methyl butyrate, ethyl butyrate, pentyl butyrate, methyl salicylate, Ethyl caproate Pentyl valerate, ethyl-2-methylpropanoate, ethylbutanoate, methyl-2-methylbutanoate, ethyl-2-methylbutanoate, ethyl-3-methylbutanoate, methyl-3 -Hydroxybutano , Methylhexanoate, ethylhexanoate, hexylhexanoate, methyl-3-hydroxyhexanoate, octylhexanoate, ethyloctanoate, methyl-3-hydroxyoctanoate, ethyl nicotinate, Esters such as γ-hexalactone, γ-octalactone, δ-octalactone, γ-decalactone, δ-decalactone, γ-dodecalactone, δ-dodecalactone, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, capron Examples thereof include carboxylic acids such as acid, enanthic acid, caprylic acid, 2-methylpropanoic acid and 2-methylbutanoic acid, terpenes such as trans-nerolidol, cis-nerolidol and farnesol, and phenols such as eugenol and vanillin. The

The membranous support 34 that is a component of the oxidation catalyst layer 33 of the present embodiment has pores that are mesopores. In this specification, a mesopore refers to a pore having a diameter of 2 nm or more and 50 nm or less determined by the BET method in which an opening on one surface communicates with another opening on the same or different surface. .
The shape of the mesopores and the positional relationship between the openings are not particularly limited. For example, even in a cylinder shape in which the upper surface and the lower surface of the membrane-like support 34 communicate with each other in a straight line, the mesopores are branched inside the support. A so-called communication structure that is connected to the pores may be used. Since a larger number of openings are connected in the communication structure, even if moisture adheres to the inside of the support, the air permeability is unlikely to be impaired. Therefore, the communication structure is more preferable.

  Here, it is preferable that the average diameter of the mesopores by the BET method is 2 nm or more and 10 nm or less because the particle diameter of the supported oxidation catalyst particles is also within the above range and a more highly active catalyst body can be obtained. In addition, the diameter of the pore which the support body 34 which concerns on this embodiment has is the value computed using the automatic specific surface area / pore distribution measuring apparatus by BET method.

  In the present embodiment, the oxidation catalyst particles are supported in the mesopores of the membrane support 34. As the oxidation catalyst particles, platinum or palladium particles having a catalytic function for promoting an oxidative decomposition reaction can be used alone or in combination.

Further, if the average particle diameter of the oxidation catalyst particles is 10 nm or less (more preferably 1 nm or more and 10 nm or less, and even more preferably 1 nm or more and 6 nm or less), the specific surface area of the oxidation catalyst particles is increased and the catalytic activity is dramatically improved. And since the oxidation efficiency of the organic gas in to-be-processed gas increases further, it is preferable.
In addition, the particle size of the oxidation catalyst particle can be obtained by calculating the particle size in an image photograph of a transmission electron microscope (TEM) and obtaining the average particle size.

  These oxidation catalyst particles are preferably supported by 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass with respect to the oxidation catalyst layer 33. When the amount is more than 20% by mass, the oxidation catalyst particles are likely to aggregate with each other, and the catalytic activity is reduced as compared with the case where the oxidation catalyst particles are within the range. It is not preferable because sufficient catalytic activity cannot be obtained.

  The oxidation catalyst layer may contain promoter particles and various metal elements in addition to the oxidation catalyst particles, and is not particularly limited. Specifically, the catalyst may be a mixture of cocatalyst particles obtained by combining the cocatalyst and oxidation catalyst particles and oxidation catalyst fine particles, or a composite catalyst composed of composite particles obtained by combining various metal elements with catalyst particles. When the oxidation catalyst particles are used alone or when a promoter is mixed with the oxidation catalyst particles, the oxidation catalyst particles may be within the above-mentioned size range. Examples of metal particles (nanoparticles) other than the catalyst particles used in the promoter or composite catalyst include base metals and oxides thereof. Two or more kinds of these noble metal and oxide thereof, base metal and oxide thereof may be mixed and supported on the inner surface of the membrane-like support 34.

  The membranous support 34 having mesopores according to the present embodiment may be anything as long as it has mesopores and can support the oxidation catalyst particles in the mesopores. In view of the fact that it may be produced including a step of forming mesopores and removing the compound by heating, a material that does not deteriorate at a heating temperature or higher is preferable.

Examples of the metal oxide constituting the film support 34 include γ-Al ₂ O ₃ , α-Al ₂ O ₃ , θ-Al ₂ O ₃ , η-Al ₂ O ₃ , and amorphous Al ₂ O _3. , TiO ₂ , ZrO ₂ , SnO ₂ , SiO ₂ , MgO, ZnO ₂ , Bi ₂ O ₃ , In ₂ O ₃ , MnO ₂ , Mn ₂ O ₃ , Nb ₂ O ₅ , FeO, Fe ₂ O ₃ , Fe ₃ O ₄ , Sb ₂ O ₃ , CuO, Cu ₂ O, NiO, Ni ₃ O ₄ , Ni ₂ O ₃ , CoO, Co ₃ O ₄ , Co ₂ O ₃ , WO ₃ , CeO ₂ , Pr ₆ O ₁₁ , Y Examples thereof include single inorganic oxides such as ₂ O ₃ , In ₂ O ₃ , PbO, and ThO ₂ . Also, for example, SiO ₂ -Al ₂ O ₃ , SiO ₂ -B ₂ O ₃ , SiO ₂ -P ₂ O ₅ , SiO ₂ -TiO ₂ , SiO ₂ -ZrO ₂ , Al ₂ O ₃ -TiO ₂ , Al ₂ O ₃ −ZrO ₂ , Al ₂ O ₃ −CaO, Al ₂ O ₃ −B ₂ O ₃ , Al ₂ O ₃ −P ₂ O ₅ , Al ₂ O ₃ −CeO ₂ , Al ₂ O ₃ −Fe ₂ O _{3 , TiO 2 -CeO 2, TiO 2} -ZrO 2, TiO 2 -WO 3, ZrO 2 -WO 3, SnO 2 -WO 3, CeO 2 -ZrO 2, SiO 2 -TiO 2 -ZrO 2, Al 2 O 3 film-like support 34 is composed of _{-TiO 2 -ZrO 2, SiO 2 -Al} 2 O 3 -TiO 2, SiO 2 -TiO 2 -CeO 2, composite oxides such as cerium-zirconium-bismuth composite oxide You may do it. Note that the cerium-zirconium-bismuth composite oxide is a solid solution represented by the general formula _{Ce 1-X-Y Zr X} Bi Y O 2-δ, X, Y, the value is 0.1 ≦ X ≦ each [delta] 0 .3, 0.1 ≦ Y ≦ 0.3, 0.05 ≦ δ ≦ 0.15.

What is necessary is just to select the material of the film-form support body 34 according to various environmental conditions in which the organic gas reduction apparatus 100 of this embodiment is used. SiO ₂ is more desirable because it can support the oxidation catalyst particles more firmly and can adhere more firmly to the substrate.

The oxidation catalyst layer 33 of this embodiment is formed on the base material 31 as described above. It is preferable to form the oxidation catalyst layer 33 of the present embodiment on the substrate 31 because the thickness of the oxidation catalyst layer 33 of the present embodiment can be easily reduced. The shape of the base material 31 is not particularly limited as long as it has air permeability. For example, the base material 31 has a sheet-like shape in which a large number of through holes are formed by punching, a fiber shape, a cloth shape, a mesh shape, a woven fabric, It can be set as the fiber structure (filter shape) comprised from a net | network thing, a nonwoven fabric, etc. In addition, various shapes and sizes suitable for the purpose of use can be used as appropriate.
By using the base material 31, the film-like shape of the support can be easily maintained.

  Since the base material 31 may be heated when the film-like support 34 of the oxidation catalyst layer 33 is formed, it is desirable to use a heat-resistant material that can withstand the heating temperature. Specifically, metal materials, ceramics, glass, carbon fibers, silicon carbide fibers, heat resistant organic polymer materials, and the like are preferable, and metals, metal oxides, and glass are more preferable.

  Metal materials used for the base material 31 include refractory metals such as tungsten, molybdenum, tantalum, niobium, TZM (Titanium Zirconium Molybdenum), W-Re (tungsten-rhenium), noble metals such as silver and ruthenium, and their Alloys or oxides, special metals such as titanium, nickel, zirconium, chromium, inconel, hastelloy, general metals such as aluminum, copper, stainless steel, zinc, magnesium, iron, and alloys containing these general metals or oxidation of these general metals Can be used. Further, the above-described metal, alloy, or oxide film may be formed on another inorganic material by various plating and vacuum deposition, a CVD method, a sputtering method, or the like.

  Note that a natural oxide thin film is usually formed on the metal surface and the alloy surface thereof. When the film-like support 34 is formed of a silane compound, the base 31 and the film are formed using the natural oxide thin film. The shaped support 34 can be firmly fixed. In this case, it is preferable to remove oil and dirt adhering to the surface of the oxide thin film in advance by an ordinary known method in order to fix stably and firmly. Also, instead of using a natural oxide film, an oxide thin film is chemically formed on a metal surface or alloy surface by a known method, or an oxide thin film is formed by a known electrochemical method such as anodic oxidation. Also good.

  Furthermore, examples of the ceramic used for the base material 31 include ceramics such as earthenware, ceramics, gypsum, magnetism, and ceramics such as glass, cement, gypsum, enamel and fine ceramics. Examples of the composition of the ceramic to be configured include elemental, oxide, hydroxide, carbide, carbonate, nitride, halide, and phosphate ceramics. These composites may be used.

  Further, as the ceramic used for the substrate 31, further, barium titanate, lead zirconate titanate, ferrite, alumina, forsterite, zirconia, zircon, mullite, steatite, cordierite, aluminum nitride, silicon nitride, Examples thereof include silicon carbide, new carbon, and new glass, and ceramics such as high-strength ceramics, functional ceramics, superconducting ceramics, nonlinear optical ceramics, antibacterial ceramics, biodegradable ceramics, and bioceramics.

  Moreover, as glass used for the base material 31, soda lime glass, potash glass, crystal glass, quartz glass, chalcogen glass, uranium glass, water glass, polarizing glass, tempered glass, laminated glass, heat resistant glass / borosilicate glass, bulletproof Glasses such as glass, glass fiber, dichroic, gold stone (brown stone / sand gold stone / purple gold stone), glass ceramics, low melting point glass, metallic glass, and saphiret can be used.

  In addition to the base material 31, normal Portland cement, early-strength Portland cement, ultra-early strong Portland cement, medium heat Portland cement, low heat Portland cement, sulfate-resistant Portland cement, and Portland cement blast furnace slag, fly ash, It is possible to use cement such as blast furnace cement, silica cement, and fly ash cement, which are mixed cements to which a siliceous mixed material is added.

In addition, titania, zirconia, alumina, ceria (cerium oxide), zeolite, apatite, silica, activated carbon, diatomaceous earth, or the like can be used for the base material 31. Furthermore, a metal oxide made of chromium, manganese, iron, cobalt, nickel, copper, tin, or the like can be used for the base material 31.
Furthermore, the base material 31 is made of heat such as polyimide, polyether ether ketone, polyphenylene sulfide, polyaramide, polybenzothiazole, polybenzoxazole, polybenzimidazole, polyquinoline, polyquinoxaline, fluororesin, phenol resin or epoxy resin. It is also possible to use a heat-resistant organic polymer material known to those skilled in the art, such as a curable resin.

  Next, an example of a method for obtaining the oxidation catalyst layer 33 of the present embodiment will be described. The oxidation catalyst layer 33 is formed by forming a membranous support 34 having pores having a mesopore diameter on a gas-permeable substrate 31 and supporting the oxidation catalyst particles in the mesopores of the obtained membranous support 34. Can be obtained.

In the method, first, the film-like support 34 is formed.
The membranous support 34 having mesopores forms, for example, a membranous precursor on the substrate 31 in a state in which a substance acting as a mesopore template inside the support is contained, and then as a template It can be obtained by decomposing and removing the acting substance.

  An example of the method will be described. First, a solution containing a surfactant as a template and a hydrolyzate of alkoxysilane or metal alkoxide (hereinafter referred to as a precursor solution) is prepared. Specifically, alkoxysilane or metal alkoxide is added to a solution in which a surfactant as a template is dissolved, and pH is adjusted to hydrolyze the alkoxysilane or metal alkoxide. This produces a silanol group or a metal hydroxide. The surfactant forms micelles in the solution and becomes a template for mesopores. The precursor solution is applied to the substrate 31 and heated to volatilize the solvent, and the silanol group or metal hydroxide is condensed and cured to form the precursor of the film-like support 34 on the surface of the member. Thereafter, by further baking to a high temperature of 300 ° C. or higher, the surfactant as a template in the precursor is removed by decomposing and volatilizing, and the membranous support 34 having mesopores is obtained.

The precursor solution can be configured to include, for example, three components: (1) alkoxysilane or metal alkoxide, (2) solvent (solvent), and (3) surfactant. Since water is required when hydrolyzing an alkoxysilane or metal alkoxide in a solution, the solvent may be water or a mixed solvent of water and a water-soluble organic solvent such as methanol or ethanol. preferable. Further, a catalyst for hydrolysis treatment of alkoxysilane or metal alkoxide may be further included in the solution, and it is preferable to use an acid such as nitric acid or hydrochloric acid as the catalyst.
The ratio of the surfactant, alkoxysilane, or metal alkoxide is not particularly limited and can be set as appropriate. By changing the molar ratio of surfactant / alkoxysilane or metal alkoxide, the pore volume ratio and the porosity of the obtained film-like support can be controlled.

  In order to obtain a film-like support 34 having a more uniform film thickness, it is preferable not to generate a precipitate in the precursor solution before application to the substrate 31, and the precursor is obtained by using an alcohol solution having an acidic pH. Precipitation can be avoided. Alternatively, the precipitation can be achieved by adjusting only the molar ratio of water to alkoxysilane or metal alkoxide, adjusting the molar ratio with pH adjustment, or adding alcohol, or both molar ratio adjustment and alcohol addition. It can also be avoided.

As the surfactant, polyoxyethylene ether, polyalkylene oxide block copolymer and the like can be used. As polyoxyethylene ether, C ₁₂ H ₂₅ (CH ₂ CH ₂ O) ₁₀ OH, C ₁₆ H ₃₃ (CH ₂ CH ₂ O) ₁₀ OH, C ₁₈ H ₃₇ (CH ₂ CH ₂ O) ₁₀ OH, C ₁₂ H ₂₅ (CH ₂ CH ₂ O) ₄ OH, C ₁₆ H ₃₃ (CH ₂ CH ₂ O) ₂ OH, and the like. Examples of the polyalkylene oxide block copolymer include block copolymers of ethylene oxide and propylene oxide.

  Since the differential length of the surfactant affects the mesopore diameter, the surfactant may be selected according to the target mesopore diameter. Moreover, you may make it add hydrophobic compounds, such as mesitylene, Since the said hydrophobic compound can increase the micelle diameter in a precursor solution, it can be used for preparation of a mesopore diameter.

  The alkoxysilane used is tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane. Hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, and the like. As the metal alkoxide, tetrapropoxyaluminum, tetrapropoxytin, tetrapropoxytitanium, tetrapropoxyzirconium and the like can be used.

  The method for applying the precursor solution to the base material 31 is not limited as long as the precursor solution can be uniformly and thinly applied to the base material 31. However, an unnecessary solution may be used after the spin coating method or the base material 31 is immersed in the precursor solution. A Dip & blow method for blowing off can be applied, and it may be selected according to the shape of the base material 31 to be applied. Moreover, the heating conditions for removing the template molecules after forming the precursor are not particularly limited, and for example, the precursor may be heated at 300 to 600 ° C.

Next, the oxidation catalyst particles are supported on the mesopores of the membrane support 34 to obtain the oxidation catalyst layer 33 of the present embodiment.
First, the mesoporous film 34 is contacted with a solution (hereinafter referred to as a metal compound solution) in which a platinum compound and / or a palladium compound corresponding to the oxidation catalyst particles to be supported is dissolved. A metal compound solution is introduced into the pores. Then, the oxidation catalyst layer 33 of the present embodiment can be obtained by performing oxidation and / or reduction treatment to form oxidation catalyst particles in the mesopores.

Specifically, for example, after the film-like support 34 is immersed in a metal solution, firing and / or reduction treatment can be performed.
More specifically, while heating and stirring the metal compound solution at 20 to 90 ° C., preferably 50 to 70 ° C., the pH is adjusted to 3 to 10, preferably 5 to 8, using an alkaline solution. Thereafter, the base material 31 on which the film-like support 34 is formed is immersed in the metal compound solution, followed by vacuum degassing treatment to infiltrate the metal compound solution into the pores, and then 200 to 600 By carrying out heating and baking at 0 ° C., particles containing platinum oxide and / or palladium oxide in the pores can be obtained.

  In addition, after impregnating the metal compound solution into the pores as described above, a hydrogen reduction method in which baking is performed at 200 to 600 ° C. and a hydrogen stream at 100 to 300 ° C., a liquid phase reduction method in which the solution is immersed in a sodium borohydride solution, etc. The oxidation catalyst particles can also be obtained in the pores by performing a known reduction operation. In addition, depending on the kind of platinum compound and / or palladium compound to be used, the metal particles can be obtained in the pores only by heating and baking treatment at 200 to 600 ° C. without performing the above-described known reduction operation. Further, the reduction of platinum oxide and / or palladium oxide may be limited to a part, and platinum and / or palladium alone and platinum oxide and / or palladium oxide may coexist in the oxidation catalyst particles in the mesopores. .

Examples of the platinum compound include chloroplatinic acid, dinitrodiammine platinum, and dichlorotetraammine platinum. Examples of the palladium compound include dinitrodiammine palladium and ammonium chloropalladate.
The concentration of the platinum compound and / or the palladium compound in the metal compound solution is not particularly limited, but it is difficult to aggregate the generated oxidation catalyst particles by preparing the solution as 1 × 10 ⁻² to 1 × 10 ⁻⁵ mol / L. Therefore, it is preferable.

Next, a mechanism for blowing the gas to be processed to the oxidation catalyst layer 33 according to the present embodiment will be described. The mechanism corresponds to the gas supply unit of the present invention, and is hereinafter also referred to as a blower mechanism 10.
The blowing mechanism 10 according to the present embodiment forcibly brings the gas to be processed into contact with the oxidation catalyst layer 33 by blowing the gas to be processed to the oxidation catalyst layer 33. Thereby, the organic gas concentration contained in the gas can be reduced more efficiently. Therefore, the blowing mechanism 10 only needs to be able to deliver an amount of air that can be oxidized by the catalyst in the oxidation catalyst layer 33, and the necessary amount of air may be designed based on the capacity design of the device. It is desirable to set it above 150,000 / h.

When the space velocity of the blast is less than 10,000 / h, the amount of gas to be processed delivered to the oxidation catalyst layer 33 is small, and the amount of organic gas oxidized and removed is small. The amount of reduction in organic gas concentration in the environment where is installed is small. When the space velocity is higher than 150,000 / h, the oxidation removal rate of the catalyst decreases, so the decrease in the concentration of organic gas in the gas to be treated is small, and the apparatus 100 is installed as compared with the case where it is within the range. Reduces the amount of organic gas concentration in the environment.
The above space velocity is defined as the volume per unit time of the gas to be processed that has passed through the oxidation catalyst layer 33 divided by the volume of the catalyst layer 33.

  The gas to be treated flows in a direction (Y-axis direction in FIG. 2) perpendicular to the film thickness direction of the oxidation catalyst layer 33 (membrane support 34), and the gas to be treated diffuses and penetrates into the oxidation catalyst layer 33. The contact form is desirable. As shown in FIG. 3, if the gas to be processed is allowed to flow parallel to the film thickness direction of the oxidation catalyst layer 33, all the gas to be processed must pass through the mesopores of the oxidation catalyst layer. It becomes difficult to obtain the above-mentioned preferable space velocity.

  In addition, when the oxidation catalyst layer 33 is formed on the surface of the fiber assembly such as a mesh or a non-woven fabric, if the oxidation catalyst layer 33 is formed so as not to block the opening of the fiber assembly, microscopically, the fiber assembly An oxidation catalyst layer 33 is formed on the surface of each fiber. That is, the base material 31 in FIG. 2 corresponds to one of the fibers forming the fiber assembly. At this time, the gas to be treated can flow along the surface of each fiber. Therefore, even if the gas to be processed is transmitted in the same direction as the gas is transmitted through the normal filter, that is, in the direction orthogonal to the plane of the fiber assembly, the above-described gas to be processed is in the film thickness direction of the oxidation catalyst layer 33. Thus, it is possible to obtain a suitable space velocity by satisfying the orthogonal flow state.

For example, a known blower such as the electric fan 11 may be used as the blower mechanism, and the blower mechanism is not particularly limited. In addition, although the air supply mechanism comprised by an air blower etc. was mentioned as an example and demonstrated as a gas supply part, it is not limited to this, It is comprised so that to-be-processed gas may be supplied to the oxidation catalyst layer 33 in an apparatus. That's fine.
Further, the air blowing mechanism may be arranged so that the air flow generated by the air blowing mechanism 10 or the like comes into contact with a member having the oxidation catalyst layer 33 or a member having a functional layer other than a member carrying an antibacterial agent described later. For example, a dustproof filter that removes floating substances such as dust in the air can be used as the functional layer. By installing the dustproof filter upstream of the oxidation catalyst layer 33, the suspended matter in the air adheres to the oxidation catalyst layer 33, obstructs the contact between the gas to be treated and the catalyst, and the organic gas does not decompose. It can contribute to prevention.

  The power source of the blower mechanism 10 such as the electric fan 11 may be alternating current or direct current. In the case of direct current, it is sufficient to supply power to the air purifier with a primary or secondary battery or via an AC adapter. If the battery is built in, it can be easily stored in a storage room that does not have an outlet. The organic gas reduction device 100 can be installed. On the other hand, in the case of an AC power source or a DC power source converted by an AC adapter, there is no need for battery replacement required for a built-in battery power source, and continuous operation can be easily performed. The type of power source may be appropriately selected according to the installation conditions of the device.

  In the apparatus 100 of the present embodiment, the gas to be treated is disposed on the member 50 such as a filter carrying a compound having at least one of antibacterial, antifungal and antiviral properties (hereinafter also simply referred to as an antibacterial agent). You may install in the at least one before and behind the member 30 which has the oxidation catalyst layer 33 so that it may permeate | transmit. By killing bacteria, mold spores, and viruses floating in the gas to be treated, especially in the atmosphere, it also prevents the deterioration caused by bacteria, molds, and viruses in articles and building interiors such as fruits and vegetables stored in the environment. Can be granted.

An antibacterial agent means a substance capable of killing bacteria and / or molds and / or viruses. Examples of the antifungal compound include silver, copper, zinc, tin, magnesium, calcium, strontium, aluminum, manganese, nickel, titanium and other inorganic compounds such as phosphates and halogen salts, or these metals. As inorganic compounds or organic compounds supported on zeolite or the like, organic acid salts such as 8-oxyquinoline copper and sodium diacetate, halogenated organic compounds such as triclosan, chlorohexidine and 3-iodo-2-propylbutylcarbamate, bronopol Pyridines such as chlorothalonil and methylsulfonyltetrachloropyridine, imidazoles such as enylconazole, triazines such as N, N ', N "-trishydroxyethylhexahydro-s-triangine, biphenyl and orthophenylphenol Aromatic compounds such as enol, zinc pyrithione, benzalkonium chloride, benzethonium chloride, cetylpyridium chloride, alkyltrimethylammonium salts and other organic salts and complexes, chitin, chitosan, catechin, hinokitiol, mustard, wasabi essential oil, polylysine Compounds known to those skilled in the art such as natural organic compounds such as can be used.
Compounds having at least one of antibacterial and antiviral properties (hereinafter referred to as antibacterial and antiviral agents) include atoms such as polyphenol compounds, quaternary ammonium salts, inorganic copper compounds, inorganic silver compounds, zinc, iron and the like. Inorganic compounds containing copper, organic compounds containing atoms such as copper, silver, zinc, iron, platinum, iodine compounds, pyridine compounds, ester compounds, sulfamide compounds, and the like.
These antibacterial and antifungal antiviral agents may be contained in combination of two or more.

  The antibacterial and antiviral agent contained in the member 50 carrying the antibacterial agent is preferably a substance that is relatively safe and exhibits high bactericidal and / or antiviral properties in a small amount. Specifically, the antibacterial antiviral agent is a compound selected from the group consisting of a polyphenol compound, a quaternary ammonium salt, an inorganic copper compound and an inorganic silver compound, or an organic compound and copper, silver, It is preferable to contain a salt with zinc or iron. A compound selected from at least one selected from the group consisting of silver iodide (I), copper iodide (I), and copper thiocyanate (I) has a higher bactericidal property and is preferable.

  The form of the antibacterial agent in the member 50 carrying the antibacterial agent is not particularly limited as long as the air permeability of the gas to be treated is not hindered, but a particulate form that does not easily affect the air permeability is preferable. The size of the antibacterial agent particles is not particularly limited and can be appropriately set by those skilled in the art, but is preferably fine particles having an average particle diameter of 1 nm or more and less than 500 nm. If it is less than 1 nm, the material becomes unstable, so that the antibacterial agent particles aggregate and are difficult to form on the substrate. Moreover, when it is 500 nm or more, it will fall rather than the case where adhesiveness with a base material exists in the range. In addition, in this specification, the average particle diameter of antibacterial agent particles is a volume average particle diameter (D50), and can be measured using a particle size distribution meter.

  Examples of polyphenol compounds include catechin, anthocyanin, flavone, isoflavone, flavan, flavanone, rutin, theaflavin, tannin, chlorogenic acid, ellagic acid, gallic acid, propyl gallate, lignans, curcumins, and coumarins. .

  The quaternary ammonium salts include benzalkonium chloride, benzethonium chloride, methylbenzethonium chloride, cetylpyridinium chloride, cetrimonium bromide, didecyldimethylammonium chloride, domifene, octyldecyldimethylammonium chloride, dioctyldimethylammonium chloride, Stearyldimethylbenzylammonium chloride, stearyltrimethylammonium chloride, stearylpentaethoxyammonium chloride, alkylisoquinolinium bromide, domifene bromide, dimethyliminopolyethylene chloride, dimethyldimethylammonium chloride, 3-chloro-2-hydroxypropyltrimethylammonium chloride 2,3-epoxypropyltrimethylammonium chloride, lauryl chloride trimethyla Monium, cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, N-decyl-N-isononyldimethylammonium chloride, dicetyldimethylammonium chloride, dimethyldistearylammonium chloride, myristyldimethylbenzylammonium chloride, laurylpyridinium chloride, cetylpyridinium chloride, Tri (polyoxyethylene) stearylmethylammonium chloride, tri (polyoxyethylene) oleylmethylammonium chloride, distearyldimethylammonium chloride, dodecyltrimethylammonium chloride, ditallowdimethylammonium bromide, dioleyldimethylammonium bromide, stearoyl N, N- Dimethylethylenediamide dimethyl sulfate quaternized product, distearoyl diethyl Triamine dimethyl sulfate quaternized, myristyl dimethyl ethyl ammonium chloride, dioctyl dimethyl ammonium chloride, didecyl dimethyl ammonium chloride, dicetyl dimethyl ammonium chloride, dilauryl dimethyl ammonium chloride, lauryl dimethyl benzyl ammonium chloride, myristyl dimethyl dichloro benzyl ammonium chloride, coco Examples thereof include alkyldimethylbenzylammonium chloride.

  The inorganic copper compound may be a monovalent copper compound or a divalent copper compound. Inorganic copper compounds include copper oxide (I), copper sulfide (I), copper iodide (I), copper chloride (I), copper acetate (I), copper hydroxide (I), copper bromide (I) , Copper peroxide (I), copper thiocyanate (I), copper hydroxide (II), copper oxide (II), copper chloride (II), copper acetate (II), copper sulfate (II), copper nitrate (II ), Copper fluoride (II), copper iodide (II), copper bromide (II), copper iodate, copper perchlorate, copper cyanide, copper chloride ammonium, copper tetraborate, ammonium copper sulfate, amidosulfuric acid Examples include copper, ammonium chloride, copper pyrophosphate, and copper carbonate.

  Inorganic silver compounds include silver oxide (I), silver sulfide, silver iodide, silver chloride, silver bromide, copper peroxide (I), silver thiocyanate, silver sulfate, silver fluoride, silver iodate, perchlorine Examples thereof include silver oxide, silver cyanide, silver tetrafluoroborate, silver amidosulfate, silver copper hexafluorophosphate, and silver carbonate.

  Examples of the salt of an organic compound and copper include, for example, copper formate, copper acetate, copper propionate, copper butyrate, copper valerate, copper caproate, copper enanthate, copper caprylate, copper pelargonate, copper caprate, mistin Copper oxide, copper palmitate, copper margarate, copper stearate, copper oleate, copper lactate, copper malate, copper citrate, copper benzoate, copper phthalate, copper isophthalate, copper terephthalate, copper salicylate, melitto Copper oxide, copper oxalate, copper malonate, copper succinate, copper glutarate, copper adipate, copper fumarate, copper glycolate, copper glycerate, copper gluconate, copper tartrate, copper acetylacetone, copper ethylacetoacetate, iso Copper valerate, copper β-resorcylate, copper diacetoacetate, copper formyl succinate, copper salicylamine acid, copper bis (2-ethylhexanoate), copper sebacate, copper naphthenate Oxine copper, copper acetylacetonate, ethyl acetoacetate copper trifluoromethanesulfonate, copper phthalocyanine, copper ethoxide, copper isopropoxide, copper methoxide, dimethyl dithiocarbamates include pyrithione copper.

  Salts of organic compounds and silver include silver acetate, silver propionate, silver butyrate, copper valerate, silver caproate, silver caprylate, silver caprate, silver myristate, silver palmitate, silver margarate, stearic acid Silver, silver oleate, silver neodecanoate, silver lactate, malic acid, silver citrate, silver phthalate, silver isophthalate, silver terephthalate, silver salicylate, silver benzoate, silver melitrate, silver toluenesulfonate, oxalic acid Silver, silver malonate, silver succinate, silver glutarate, silver adipate, silver fumarate, silver glycolate, silver glycerate, silver gluconate, silver tartrate, acetylacetone silver, ethyl ethylacetoacetate, silver isovalerate, β -Silver resorcylate, silver diacetoacetate, silver formylsuccinate, silver 2-ethylhexanoate, silver sebacate, silver naphthenate, silver trifluoromethanesulfonate, Taroshianin silver, silver ethoxide, silver isopropoxide, silver methoxide, diethyldithiocarbamate, silver silver pyrithione and the like.

  Examples of the salt of an organic compound and iron include ferric citrate / n-hydrate, iron gluconate, iron citrate, iron fumarate, iron oxalate, and iron phthalocyanine.

  In addition, as a salt of an organic compound and zinc, zinc citrate, zinc gluconate, zinc malate, zinc formate, zinc lactate, zinc oxalate, pyrithione zinc, bis (dimethyldithiocarbamate) zinc, ethylenebis (dithiocarbamate) ) Zinc, zinc acetate, zinc acrylate, zinc benzoate, zinc butyrate, zinc glycerate, zinc glycolate, zinc picolinate, zinc propionate, zinc salicylate, zinc tartrate, zinc undecylenate, zinc malonate, zinc succinate , Zinc phthalocyanine, zinc glutarate, zinc phenolsulfonate, zinc cresolsulfonate, zinc toluenesulfonate, zinc benzenesulfonate, zinc methanesulfonate, zinc 2-propanolsulfonate, and the like.

  For example, as one aspect, the member 50 carrying the above-described antibacterial agent or the like may be installed further upstream of the member 30 having the oxidation catalyst layer 33 in the air flow direction. The mode of carrying is not particularly limited, and a method known to those skilled in the art may be used. For example, an antibacterial agent such as particles may be adsorbed or adhered to the surface of the substrate. Adsorption or adhesion may be physical adhesion by physical interaction such as electrostatic attraction or van der Waals force, or may be based on The material and antibacterial agent particles may be either chemically bonded by chemical bonding via a coupling molecule such as a silane monomer, but chemical bonding is desirable because the substrate and antibacterial agent or the like are firmly bonded.

  For physical adhesion, the base material is immersed in a solvent in which an antibacterial agent or the like is dispersed, and then the dispersed solvent is volatilized. As the solvent for dispersing the antibacterial agent, general-purpose solvents such as water, methanol, ethanol, MEK, acetone, xylene, and toluene can be used.

  In order to adhere more firmly, the surface of the substrate may be previously hydrophilized by plasma treatment or a resin binder may be added. A known binder can be used as the resin binder. Specific examples include polyester resin, amino resin, epoxy resin, polyurethane resin, acrylic resin, water-soluble resin, vinyl resin, fluororesin, silicon resin, fiber resin, phenol resin, xylene resin, toluene resin, and natural resin. May be dry oils such as castor oil, linseed oil and tung oil.

  Chemical adhesion is fixing to a substrate through a chemical bond with a binder. The binder to be used is not particularly limited, but the silane monomer and the oligomer that is a polymer thereof have a low molecular weight, and therefore, the contact between the antibacterial agent particles and the bacteria is low and effective. It is preferable because it can be sterilized. Moreover, since the molecular weight is low, the adhesiveness with the base material is high, and the antimicrobial agent particles can be stably supported on the base material.

Specific examples of the silane monomer include silane monomers represented by a general formula of X—Si (OR) _n (n is an integer of 1 to 3). X is a functional group that reacts with an organic substance, such as a vinyl group, an epoxy group, a styryl group, a methacrylo group, an acryloxy group, an isocyanate group, a polysulfide group, an amino group, a mercapto group, or a chloro group. OR is an alkoxy group such as a hydrolyzable methoxy group or ethoxy group, and the three functional groups related to the silane monomer may be the same or different. These alkoxy groups composed of methoxy groups and ethoxy groups are hydrolyzed to form silanol groups. It is known that functional groups having silanol groups, vinyl groups, epoxy groups, styryl groups, methacrylo groups, acryloxy groups, isocyanate groups, and unsaturated bonds have high reactivity. The antibacterial agent particles are firmly held on the surface of the base material by chemical bonding through such a reactive silane monomer.

  Examples of the silane monomer represented by the above general formula include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-amino. Propyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxy Silane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3- Methacryloki Cypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-aminopropyltrimethoxysilane 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-2- (aminoethyl)- 3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane 3-mercaptopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, special aminosilane, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, methyltrimethoxy Silane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, hexamethyldisilazane, hexyltrimethoxysilane, decyltrimethoxysilane, hydrolyzable group-containing siloxane, fluoroalkyl group-containing oligomer, methylhydrogensiloxane, Examples thereof include silicone quaternary ammonium salts.

  Examples of the silane oligomer include KC-89S, KR-500, X-40-9225, KR-217, KR-9218, KR-213, and KR-510 manufactured by Shin-Etsu Chemical Co., Ltd., which are commercially available. These silane oligomers may be used alone or in combination of two or more, and may be used in combination with one or more of the aforementioned silane monomers.

Next, the heating unit 38 for heating the oxidation catalyst unit 33 will be described.
The moisture adsorbed in the mesopores of the oxidation catalyst layer 33 is volatilized and removed by heating by the heating unit 38. By removing moisture by heating by the heating unit 38, contact inhibition between the oxidation catalyst particles and the organic gas component in the gas to be treated is eliminated, and the catalytic activity of the oxidation catalyst layer 33 can be recovered.

  Accordingly, the heating unit 38 operates so as to heat the oxidation catalyst layer 33 in a state where moisture is adsorbed in the mesopores of the oxidation catalyst layer 33 and the action of the oxidation catalyst particles is inhibited and the activity of the catalyst body is reduced. If it is sufficient and moisture is not adsorbed or if there is no problem with the oxidation reaction in a small amount, the heating unit 38 may not be operated so that excess heat is transferred to the gas to be treated and the temperature does not rise. .

  The mechanism and method for heating the oxidation catalyst layer 33 are not particularly limited. For example, it is sufficient that the water adsorbed in the mesopores of the oxidation catalyst layer 33 can be heated to a temperature at which the water can be volatilized and diffused. Furthermore, although depending on the space velocity at which the gas to be treated is blown to the oxidation catalyst layer 33, the heating temperature is desirably 200 ° C. or lower. When the temperature exceeds 200 ° C., the gas to be treated passes through the heated oxidation catalyst layer 33, and then the gas temperature rises greatly. For example, the organic gas reduction device of this embodiment is used in a low-temperature environment such as a refrigerator. It is not preferable because the temperature of the usage environment is raised. The heating time required for the activity recovery is affected by factors such as the amount of moisture adsorbed on the oxidation catalyst layer 33, the film thickness and breathability of the oxidation catalyst layer 33, the heating temperature, and the space velocity. If it is within the range, it may be heated for 1 to 120 minutes.

The heating unit 38 can be configured by a heat source, for example. The heat source is not particularly limited, and a heat source known to those skilled in the art can be used, but an electric heater 36 that simplifies the structure of the apparatus is desirable. A heat source such as the electric heater 36 may be included in the base material 41 that supports the above-described oxidation catalyst layer, and heat may be transferred to the oxidation catalyst layer 33 through the base material 41. The electric heater 36 is connected to a power source via a power supply wiring 37. Alternatively, heat may be transferred by installing the electric heater 36 or another member having the electric heater in close contact with or close to the member 30 carrying the oxidation catalyst layer 33.
Alternatively, the oxidation catalyst layer 33 may be heated by irradiating electromagnetic waves from the outside such as infrared rays or microwaves. While microwaves can directly generate heat, the film-like support 34 is preferably a heat source that hardly generates heat and hardly heats the gas to be treated when it is made of an inorganic material.

  In order to suppress an increase in the gas temperature of the gas to be processed, it is desirable to heat the oxidation catalyst layer 33 to the minimum necessary as described above. Therefore, it is more preferable to operate the heating unit 38 of this embodiment intermittently. The method of intermittent operation is not particularly limited, but it is possible to manually switch ON / OFF the power supply to the heater, automatically install it with a timer function, and change the concentration of organic gas to be removed by oxidation. What is necessary is just to make it heat based on a method well-known to those skilled in the art, such as switching automatically when it reaches a specified value by monitoring.

  When intermittent operation is performed at regular intervals, the intermittent interval depends on the amount of moisture adsorbed in the mesopores of the oxidation catalyst layer 33, but the operation time (A) and non-operation time (B) The time when B / A satisfies the numerical value between 23 and 335 is preferable. When the value of B / A is smaller than 23, the operation time interval is short, and the temperature of the gas to be processed is likely to rise as compared with the case where it is 23 or more. If it is larger than 335, the operating time interval becomes longer, and it is not preferable because the state in which the catalytic activity of the mesoporous catalyst body is lowered is likely to occur as compared with the case where it is 335 or less.

  Since the oxidation catalyst layer 33 of the present embodiment has a film shape, the heat generated from the heat source is efficiently transmitted to the water molecules in the mesopores as compared with other shapes of catalyst bodies such as powder. Therefore, since the water in the mesopores is volatilized and removed from the mesopores quickly, the amount of heating necessary for removing the water is further reduced, and the temperature of the gas to be treated can be suppressed from increasing, which is preferable.

  By using the organic gas reduction device 100 of the present embodiment, in an environment lower than room temperature (23.4 ° C.) and higher than normal (relative humidity 50%), an organic material such as ethylene gas in a gas, particularly in the atmosphere. Oxidation and removal of gases even at trace concentrations (depending on the size of the oxidation catalyst layer and the presence or absence of a blower, but about 0.5 ppm), for example, harmful organic gases such as low ethylene gas concentration that is good for storing fruits and vegetables A gaseous environment with reduced components can be provided.

As mentioned above, although the organic gas reduction apparatus of this embodiment was demonstrated, this invention is not limited to this, It can also be set as another aspect.
For example, although the organic gas reduction device has been described by exemplifying the configuration including the member including the oxidation catalyst unit, the air blowing unit, and the heating unit, the organic gas reduction device may be configured not to include the air blowing unit.
Further, although the description has been given by taking the embodiment in which the oxidation catalyst portion has a membrane-like support and the oxidation catalyst particles are supported in the mesopores of the membrane-like support, the present invention is not limited to this, and other embodiments are possible. May be. For example, the oxidation catalyst part may have a particulate support having mesopores, and the oxidation catalyst particles may be supported in the mesopores of the particulate support.

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples.

Example 1
10.4 g of tetraethoxysilane (TEOS) was put in a beaker, and 12.0 g of ethanol was further added. To this, 4.5 g of 0.01M hydrochloric acid was further added and stirred at room temperature for 20 minutes (solution A). In a separate beaker, 3.3 g of a nonionic surfactant (Brij56) and 8.0 g of ethanol were added and stirred at room temperature for 30 minutes (Liquid B). Then, B liquid was added to A liquid, mixed under room temperature conditions, and further stirred for 3 hours to obtain a precursor solution of mesoporous silica. A ceramic honeycomb (manufactured by Iwatani Corporation) serving as a base material was immersed in the mesoporous silica precursor solution, and the pressure was reduced for 15 minutes. Thereafter, the ceramic honeycomb was pulled up, and the excess solution was removed by air blowing. Then, the temperature was raised at 1 ° C./min and fired at 450 ° C. for 4 hours to obtain a ceramic honeycomb substrate on which the mesoporous silica film was fixed.
Thereafter, the ceramic honeycomb with the mesoporous silica film immobilized thereon is immersed in a solution containing diamine dinitroplatinum nitrate, and the excess solution is removed by air blow, and the mixture is reduced to 250 ° C. in a reducing gas containing 10% hydrogen gas and 90% nitrogen gas. After firing for 1 hour, a honeycomb substrate having a platinum oxidation catalyst layer was obtained.
The amount of Pt supported on the mesoporous silica film (including Pt particles, hereinafter the same) was 1 wt%. When the pore diameter was measured by the BET method, it was 3.2 nm. The mesoporous silica film had a thickness of 500 nm. Moreover, when the particle size of Pt was observed with TEM, it was 3 nm.

  A plurality of heating elements incorporating an electric heater were attached in close contact with the outer periphery of the honeycomb substrate obtained above. Further, a surface thermometer sensor was attached to the outer periphery of the honeycomb substrate so as not to contact the heating element. In addition, a blowing mechanism (blowing the gas to be treated in a direction perpendicular to the film thickness direction) was attached so that the gas to be treated permeated through the oxidation catalyst layer, and an organic gas reduction device was produced.

[Test Example 1]
The inside of the sealed space with a volume of 120 L was adjusted so that the temperature was 5 ° C., the humidity was 90%, and the ethylene concentration was 0.5 ppm. Thereafter, the organic gas reduction device of Example 1 was installed in the sealed space, and the change in ethylene concentration in the sealed space over time was blown to the honeycomb substrate having the oxidation catalyst layer at a space velocity of 48,000 / h. Measured. The space velocity was calculated from the air volume of 14.4 m ³ / h with respect to the volume of the oxidation catalyst layer of 300 cm ³ (10 cm × 10 cm × 3 cm).

[Test Example 2]
After carrying out Test Example 1, the organic gas reduction device was continuously operated for 14 days in an environment where the temperature was 5 ° C., the humidity was 90%, and the ethylene concentration was 0.5 ppm. After 14 days, the same method as in Test Example 1 was performed.

[Test Example 3]
After carrying out Test Example 2, the oxidation catalyst layer of the organic gas reduction device was heat-treated at 50 ° C. for 1 hour. Then, it implemented by the method similar to Test Example 1.

[Test Example 4]
After performing Test Example 2, the oxidation catalyst layer of the organic gas reduction device was heat-treated at 80 ° C. for 1 hour. Then, it implemented by the method similar to Test Example 1.

[Test Example 5]
After performing Test Example 2, the oxidation catalyst layer of the organic gas reduction device was heat-treated at 140 ° C. for 1 hour. Then, it implemented by the method similar to Test Example 1.

[Test Example 6]
After carrying out Test Example 2, the oxidation catalyst layer of the organic gas reduction device was heat-treated at 200 ° C. for 1 hour. Then, it implemented by the method similar to Test Example 1.

  From the results of Table 1, in Test Example 1, the ethylene concentration in the box after 6 hours was not detected, but in Test Example 2, the ethylene concentration after 6 hours was 0.35 ppm, and ethylene remained, It can be seen that the ethylene reduction ability of the apparatus was reduced by operating the apparatus continuously for 14 days.

  On the other hand, in Test Example 3 in which the oxidation catalyst layer was heat-treated, the ethylene concentration in the box after 6 hours was 0.30 ppm, indicating that the ethylene reduction ability was slightly recovered. Further, in Test Examples 4 to 6, the ethylene concentration in the box after 6 hours was not detected, and the same result as in Test Example 1 was obtained, and the ethylene reduction ability was sufficiently recovered. From the above results, the effectiveness of the present invention was shown.

DESCRIPTION OF SYMBOLS 10 Blower mechanism 11 Electric fan 30 Member which has oxidation catalyst layer 31 Base material 33 Oxidation catalyst layer 34 Film-like support 35 Ventilation part 36 Electric heater 37 Electric power supply wiring to electric heater 38 Heating part 100 Organic gas reduction apparatus

Claims (12)

An organic gas reduction device that reduces organic gas in a gas to be treated,
Oxidation catalyst particles having air permeability and having mesopores on the surface thereof and containing one or more substances selected from the group consisting of platinum and palladium supported on the mesopores and oxides thereof. A member in which an oxidation catalyst part is disposed;
An organic gas reduction device comprising: a heating unit that heats the oxidation catalyst unit.   The organic gas reduction device according to claim 1, wherein the heating unit heats the oxidation catalyst unit to 80 ° C. or more.   The organic gas reduction device according to claim 1, wherein the heating unit operates intermittently.   The organic gas reducing device according to any one of claims 1 to 3, wherein the organic gas is ethylene.   The oxidation catalyst part has a membranous support having mesopores, and the oxidation catalyst particles are supported in mesopores of the membranous support. The organic gas reduction device described in 1.   6. The organic gas reduction device according to claim 5, wherein the film-like support has a thickness of 50 nm to 1000 nm. The organic gas reduction device according to claim 5 or 6, wherein the film-like support is made of SiO ₂ .   The organic gas reduction device according to any one of claims 5 to 7, wherein an average pore diameter of the mesopores measured by a BET method is 2 nm or more and 10 nm or less.   9. The organic gas reduction device according to claim 5, wherein an average particle diameter of the oxidation catalyst particles is 1 nm or more and 10 nm or less.   The organic gas reduction device according to any one of claims 1 to 9, further comprising a gas supply unit that supplies a gas to be processed to the oxidation catalyst body.   The gas supply unit has a blowing mechanism for blowing untreated gas to the oxidation catalyst unit, and a space velocity of blowing by the blowing mechanism is 10,000 / h or more and 150,000 / h or less. 10. The organic gas reducing device according to 10. 12. The apparatus according to claim 10, further comprising a member carrying a compound having at least one of antibacterial, antifungal, and antiviral properties on the upstream side in the air flow direction of the member having the oxidation catalyst portion. The organic gas reduction device as described.