JP2018158316A - Complex of photocatalyst and adsorbent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a visible light-responsive photocatalyst-adsorbent complex for adsorbing and decomposing the materials that cause the sick house syndrome and household malodors.SOLUTION: A visible light-responsive photocatalyst-adsorbent complex has a composite of tungsten oxide and hydrogen-type high silica zeolite, where the tungsten oxide has a primary particle size of 5-100 nm, and the hydrogen-type high silica zeolite has an SiO2/Al2O3 composition ratio of 1200-2200, a beta or ZSM-5 crystal form, and a pore size of less than 5-7Å.SELECTED DRAWING: None

Description

The present invention relates to a composite of a photocatalyst and an adsorbent.
Specifically, the present invention relates to a composite of tungsten oxide and high silica zeolite having a visible light response type and high photocatalytic activity. More specifically, the present invention relates to a visible light responsive photocatalyst-adsorbent complex which is a complex of tungsten oxide and high silica zeolite.

  In recent years, houses in Japan have excellent earthquake resistance, air conditioning and heating, using aluminum sash windows, walls with high heat insulation and / or sound insulation, from traditional wooden buildings using earth walls and plaster resistant to high humidity and high temperature. It has been changed to single-family houses and / or condominiums with high energy-saving effects and high airtightness.

  In these houses and / or condominiums, because of their high airtightness, they can be generated from volatile organic compounds (VOC) generated from wallpaper, interior paint, joinery and furniture and / or kitchen waste, leftovers or toilets. The onset of sick house syndrome, which is a modern disease, which is said to be caused by malodor, has become a problem.

  Any of the above volatile organic compounds has a property of being easily vaporized when the temperature rises and increasing the amount of volatilization. Therefore, the name of Japanese sick house syndrome is derived, and it is called sick building syndrome. In the United States where a lot of paint is used indoors, as a countermeasure, the window is closed and the room temperature is raised to 30-40 ° C with a heater. The causative substance of sick building syndrome is treated and removed by baking out (heating) method, in which the chemicals are vaporized over about 3 days with occasional ventilation and replacement of indoor air.

  However, although this bake-out method is effective for paint, it is hardly effective for formaldehyde generated from plywood consisting of a laminate of multiple sheets or thick vinyl cloth. It has been known.

In order to solve the above problems, in recent years, active research has been conducted on the decomposition of odorous substances with a photocatalyst together with a deodorizing agent and a deodorizing agent.
Patent Document 1 discloses that a photocatalyst is supported on the surface of activated carbon, and the photocatalyst is excited using an ultraviolet lamp or the like to decompose odor components, but also discloses that the photocatalyst is titanium oxide. .

  Patent Document 2 is an air purification paint obtained by coating a photocatalyst and an adsorbent with a binder. As the adsorbent, high silica synthetic high silica zeolite H-type ZSM5 having a silica / alumina ratio of 5.6 to 92 is used. Although the air purification coating using the used photocatalyst is disclosed, it is also disclosed that the photocatalyst is titanium oxide.

  Patent Document 3 is a photocatalyst for decomposing a volatile aromatic compound in a gas phase, containing tungsten oxide particles as a main component, and the surface of the tungsten oxide particles being coated with titanium oxide particles. The photocatalyst for volatile aromatic compound decomposition is disclosed, wherein the coating amount of the titanium oxide particles is 3 to 45 parts by mass in terms of titanium with respect to 100 parts by mass of the tungsten oxide particles. .

  Patent Document 4 discloses a photocatalytic material in which halogen is doped in a photocatalyst including a core particle containing tungsten oxide and a cocatalyst supported on the surface of the core particle. Further, Patent Document 4 discloses that a shell layer covering the entire surfaces of the core particles and the promoter is provided, and the shell layer is made of titanium oxide.

  Furthermore, Non-Patent Document 1 describes a complete oxidative decomposition reaction of acetaldehyde with a titanium oxide / ZSM-5 zeolite photocatalyst.

JP-A-5-293165 Japanese Patent Laid-Open No. 9-249824 2012-110831 Japanese Patent Publication No. 2006-137563

J. Jpn. Soc. Powder Powder Metallurgy Vol. 54, No. 3, 175-179, Masato Takeuchi et al., “Complete Oxidative Decomposition Reaction of Acetaldehyde with Titanium Oxide / ZSM-5 Zeolite Photocatalyst”

As described above, titanium oxide itself is used as a catalyst or a coating agent in a decomposition / purification type catalyst composed of a conventional photocatalyst and an adsorbent.
This titanium oxide is known as a catalyst having a self-cleaning action by light irradiation in recent years, and a product containing this catalyst has been developed, and it is applied to tunnel inner wall painting, building outer wall painting, tents, side mirrors, etc. It is used.

However, titanium oxide is active in ultraviolet rays, but hardly absorbs visible light that occupies most of sunlight, has weak catalytic activity due to visible light, and can not exhibit its self-cleaning effect sufficiently if it is not ultraviolet light. Are known.
Therefore, the present invention is not a high-energy limited light beam such as ultraviolet rays but a catalyst activated by visible light mainly comprising sunlight, that is, a composite of a visible light responsive photocatalyst and an adsorbent, An object is to provide a visible light responsive photocatalyst-adsorbent complex.

  Therefore, as a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a volatile organic compound is adsorbed by a specific metal oxide-adsorbent complex and decomposed by irradiation with visible light. And led to the completion of this study.

  However, according to the present invention, there is provided a visible light responsive photocatalyst-adsorbent complex characterized in that tungsten oxide and high silica zeolite are complexed.

Further, according to the present invention, the _adsorbent, wherein the visible-light-responsive photocatalyst is a high silica zeolite having a SiO 2 / _Al 2 _{O 3} composition ratio 1200-2200 - adsorbent complex is provided.

  Further, according to the present invention, there is provided the visible light responsive photocatalyst-adsorbent complex, wherein the adsorbent has a beta or ZSM-5 crystal form.

  Moreover, according to this invention, the said visible light responsive type photocatalyst-adsorbent complex whose said adsorbent is a hydrogen type high silica zeolite is provided.

  In addition, according to the present invention, there is provided the visible light responsive photocatalyst-adsorbent complex, wherein the adsorbent has a pore diameter of 5 mm or more and less than 7 mm.

  In addition, according to the present invention, there is provided the visible light responsive photocatalyst-adsorbent complex, wherein the tungsten oxide has a primary particle size of 5 to 100 nm.

  Moreover, according to this invention, the said visible response type photocatalyst-adsorbent composite_body | complex to which the said high silica zeolite is added 10 to 80weight% with respect to the weight of the said tungsten oxide is provided.

  In addition, according to the present invention, there is provided the visible light responsive photocatalyst-adsorbent complex in which the visible light responsive photocatalyst further supports a cocatalyst.

  According to the present invention, the promoter is platinum, palladium or copper, a halide, oxide, hydroxide or salt thereof, and is added in an amount of 0.01 to 3% by weight based on the weight of tungsten oxide. The visible light responsive photocatalyst-adsorbent complex is provided.

  In addition, according to the present invention, there is provided the visible light responsive photocatalyst-adsorbent complex, wherein the visible light responsive photocatalyst-adsorbent complex adsorbs and decomposes a causative substance of sick house syndrome or home odor. Is done.

  Furthermore, according to the present invention, the causative substance is included in the group consisting of formaldehyde, acetaldehyde, formic acid, acetic acid, toluene, xylene, trimethylbenzene, ethylbenzene, ammonia, amine, mercaptan, hydrogen sulfide, and isovaleric acid 1 The visible light responsive photocatalyst-adsorbent complex which is the above compound is provided.

The visible light responsive photocatalyst-adsorbent complex according to the present invention is used for residential spaces, office spaces, and indoor spaces of public buildings such as schools, government offices, public halls, and private houses in single-family, low-rise and high-rise apartments or buildings. Volatile organic compounds (VOC) that can be generated from wallpaper, interior painting, fittings, furniture, etc. in the interior space of cars, automobiles, buses or trains, or cabin spaces such as ships or airplanes, or kitchen or kitchen waste It absorbs bad odors and the like that can be generated from leftover rice and can be decomposed by light from room lighting.

Further, the visible light responsive photocatalyst-adsorbent complex according to the present invention has an excellent adsorption function and oxidative decomposition function (photocatalytic function) when used repeatedly, and can be used for a long period of time.
Therefore, it is used for clothes, bedding, curtains or carpets by being used for trash bins, leftovers, filters for air purifiers, air conditioners, sprays used indoors or in cars, wallpaper coatings, or kneaded into fibers. it can. Further, it can be added to the resin or coated with the molded resin and used for toilet articles, trash cans and the like.

It is a graph which shows a time-dependent change of the aldehyde residual rate under LED light irradiation by the composite of the photocatalyst and adsorbent by this invention. It is a graph which shows a time-dependent change of the carbon dioxide production rate accompanying decomposition | disassembly of the aldehyde under LED light irradiation by the composite_body | complex of the photocatalyst and adsorbent by this invention. It is a scanning electron micrograph of the adsorption agent before the composite_body | complex formation by this invention. 2 is a scanning electron micrograph of a composite of a photocatalyst and an adsorbent according to the present invention. It is a figure which shows the change of the crystal structure of the high silica zeolite used for this invention depending on the grinding | pulverization time.

As used herein, the term “sick house syndrome” refers to a newly built home, a home that has just been remodeled, or a workplace that has moved to a new building, which makes you feel sick when you enter the room. It means a relatively new symptom that causes pain in the back of the nose, flickering eyes, coughing, and physical condition.
Among the family members, there are high probabilities that happen to housewives and infants, and the reason for this is that the time spent at home is long and the resistance to physical constitution is weak.

  The above sick house syndrome uses aluminum sash windows, metal doors, walls with high heat insulation and / or sound insulation, excellent earthquake resistance, high energy-saving effect of air conditioning and heating, high-tightness detached houses, low-rise buildings and In residential spaces, office spaces and public spaces in buildings including high-rise apartments, public spaces such as schools, government offices, government offices and public halls, and cabin spaces such as private cars, cars, buses or trains, or cabins or aircraft Because of its high air tightness, it can be generated from wallpaper, especially volatile organic compounds (VOC) that can be generated from wallpaper adhesives, indoor coatings, joinery and furniture, etc. and / or from kitchen, kitchen trash, leftovers or toilets It is said that bad odor is the cause.

  Examples of volatile organic chemical substances that can be generated from the above wallpaper, wallpaper adhesive, indoor coating, furniture and furniture include formaldehyde, acetaldehyde, formic acid, acetic acid, toluene, xylene, trimethylbenzene, and ethylbenzene.

  Moreover, ammonia, an amine, a mercaptan, hydrogen sulfide, isovaleric acid, etc. are mentioned as a chemical substance as a malodorous component which can generate | occur | produce from the garbage of kitchen, a kitchen, leftovers, or a toilet.

Visible Light Responsive Photocatalyst The visible light responsive photocatalyst according to the present invention used for the adsorption and oxidative decomposition of the volatile organic compound and / or the causative substance of bad odor or living odor is titanium dioxide (titanium oxide, TiO ₂ ), zinc oxide (ZnO), cadmium sulfide (CdS) and tungsten oxide (WO ₃ ). It is said that there is not much difference in the decomposition ability of each organic compound of these photocatalysts.

However, because titanium oxide as a photocatalyst is activated, short-wavelength light (ultraviolet rays or the like) having high energy is necessary even in sunlight.
In the case of zinc oxide and cadmium sulfide, the catalyst itself is decomposed by light absorption over a long period of time, and harmful zinc ions or cadmium ions are generated.

Therefore, tungsten oxide (WO ₃ ) is suitably used as the visible light responsive catalyst in the visible light responsive photocatalyst-adsorbent complex according to the present invention. However, the tungsten oxide used in the present invention is not limited to tungsten oxide having the chemical formula WO _3, and tungsten oxide having the chemical formula WO ₂₀ O ₅₈ , WO ₂₄ O ₆₈ or WO ₂₅ O ₇₃ can be used, and at least tungsten oxide. Any visible light responsive photocatalytic material that exhibits photocatalytic activity when irradiated with visible light may be used.

  Examples of the method for producing tungsten oxide particles used in the present invention include a method of thermally decomposing ammonium paratungstate (APT), a method of heating metallic tungsten powder in an oxygen atmosphere, and the like. When the particle size distribution of the obtained tungsten oxide is large, the tungsten oxide having a large particle size may be removed through an appropriate filter.

The tungsten oxide particles may be composed of particles having a uniform particle size or may be composed of a mixture of particles having a non-uniform particle size.
However, the primary particle diameter of tungsten oxide is preferably 5 nm or more and 100 nm or less.

When the primary particle diameter of the tantalum oxide is smaller than 5 nm, the particles tend to aggregate to form secondary particles. When the primary particle diameter is larger than 100 nm, the specific surface area decreases and the photocatalytic activity tends to decrease.
In addition, the particle diameter here is an average particle diameter calculated based on the BET specific surface area. Further, the spread (size) and distribution shape of the particle size distribution of the photocatalyst particles are not particularly limited, and a plurality of particle size distribution peaks may exist.

Cocatalyst The cocatalyst is composed of a metal or a metal compound having an electron-withdrawing property, and can be added to the visible light responsive photocatalyst-adsorbent complex according to the present invention for the purpose of enhancing the photocatalytic activity of the photocatalyst.
Examples of the promoter include metals such as platinum, gold, silver, copper, palladium, iron, nickel, ruthenium, iridium, niobium and molybdenum, and halides, oxides, hydroxides or salts thereof.

Specifically, metals such as platinum, gold, silver, copper, palladium, iron, nickel, ruthenium, iridium, niobium and molybdenum, and their chlorides, bromides, iodides, oxides, hydroxides, sulfates, Examples thereof include nitrates, carbonates, phosphates, and organic acid salts.
From the viewpoint of the catalytic ability and cost of the promoter, platinum, palladium and copper, halides, oxides, hydroxides or salts thereof are particularly preferable.

Cocatalyst addition method The cocatalyst addition method to the tungsten oxide particles is:
(1) A method of kneading tungsten oxide particles and metal particles or metal compound particles constituting a promoter;
(2) After adding tungsten oxide particles to a solution containing a metal or a metal compound constituting the promoter, the resulting solution is heated or irradiated with light to form a promoter on the surface of tungsten oxide. A method of depositing a metal or a metal compound constituting
Etc.

The cocatalyst is preferably added in a proportion of 0.01 to 3% by weight based on the weight of tungsten oxide as a photocatalyst.
When the added amount of the cocatalyst is less than 0.01% by weight with respect to the weight of tungsten oxide, the effect as a cocatalyst is reduced in the catalytic action of tungsten oxide, and high photocatalytic activity cannot be obtained.
Further, when the amount of the cocatalyst added is more than 3% by weight with respect to the weight of tungsten oxide, the surface coverage by the cocatalyst on the tungsten oxide surface increases, the amount of light reaching the tungsten oxide decreases, and the catalytic action as a photocatalyst. Is not preferred because it may decrease.

Adsorbent As the adsorbent constituting the visible light responsive photocatalyst-adsorbent complex that adsorbs and decomposes the above chemical substances, high silica zeolite is preferably used among zeolites.
The above-mentioned high silica zeolite may be in the form of fine powder, powder, beads or pellets, but the application of the visible light responsive photocatalyst-adsorbent complex according to the present invention to coating, spraying of suspension, etc. In view of the above, particles having a particle size of 0.1 to 20 μm are preferable.

The above-mentioned high silica zeolite is preferably a hydrogen type high silica zeolite whose cation is hydrogen rather than sodium and potassium from the viewpoint of the adsorption ability of chemical substances, and its crystal form is not particular, but the beta form or ZSM-5 The shape is particularly preferred.
The high silica zeolite is preferably a high silica zeolite having a high SiO ₂ / Al ₂ O ₃ composition ratio from the viewpoint of the adsorption ability of chemical substances, and a high silica zeolite having a SiO ₂ / Al ₂ O ₃ composition ratio of 1200 to 2200 is preferred. Particularly preferred.

In general, silica (Si) constituting zeolite has a structure having four oxygens (O) around it and forms a tetrahedral structure. Alumina (Al) is similar magnitude with silica, it is to enter its position instead, for alumina trivalent, Al ^- the monovalent negatively charged element called. Since it is necessary to keep the whole crystal neutral, when the proton H ⁺ plays this role, it becomes a Bransted acid point. This usually results in catalytic activity.

On the other hand, the carbonyl oxygen possessed by the aldehyde has a weak Lewis base property because it has an unshared electron pair, and is attracted to the proton H ⁺ of the high silica zeolite. Therefore, it is considered that the high silica zeolite having a high alumina ratio, that is, having a large number of brainsted acid points, has a strong bond with an aldehyde, and the low alumina ratio, that is, the high silica zeolite has a low bond with an aldehyde.
If the binding force between the aldehyde and the high silica zeolite is weak, the aldehyde once adsorbed on the high silica zeolite is easily decomposed by the photocatalyst, and it is considered that the desired effect in the present invention was obtained.

Therefore, when the SiO ₂ / Al ₂ O ₃ composition ratio is lower than 1200, the adsorptive power between the high silica zeolite and the volatile organic compound is strong, and the chemical substance adsorbed in the pores of the high silica zeolite is the high silica zeolite. It is thought that the surface is less susceptible to oxidative degradation by the photocatalyst. Further, high silica zeolite having a SiO ₂ / Al ₂ O ₃ composition ratio higher than 2200 is not easily available.
The high silica zeolite preferably has a pore diameter of 5 mm (0.5 nm) or more and less than 7 mm (0.7 nm) from the viewpoint of adsorption characteristics of a volatile organic compound or a odor-causing substance.

The addition amount of the high silica zeolite in the visible light responsive photocatalyst-adsorbent complex according to the present invention is preferably 10 to 80% by weight based on the weight of the tungsten oxide particles.
When the addition amount of the high silica zeolite is lower than 10% by weight, the adsorption effect by the high silica zeolite is low, and when it is higher than 80% by weight, the relative amount of tungsten oxide as a photocatalyst with respect to the high silica zeolite is low, It seems that it becomes difficult to obtain sufficient oxidation resolution by the photocatalyst.

Method for producing photocatalyst composite High silica zeolite powder is added to a tungsten oxide dispersion liquid in a weight ratio of 20% by weight with respect to the weight of water to 5 to 25% by weight with respect to the weight of tungsten oxide. Then, after stirring and mixing, drying and pulverization are performed to produce a photocatalyst complex.
In the production of the composite, the high silica zeolite may be pulverized in advance with a bead mill or the like and then mixed with the photocatalyst, or may be mixed while being pulverized with a bead mill or the like when the photocatalyst and the high silica zeolite are mixed.

  Alternatively, a pulverized high silica zeolite suspension obtained by previously pulverizing a 10 wt% HSZ-891HOA high silica zeolite suspension with a bead mill (manufactured by Nippon Coke Kogyo Co., Ltd.) for 30 minutes, 60 minutes or 90 minutes is used as the weight of tungsten oxide. On the other hand, it is added to a 20% tungsten oxide dispersion so as to be 50% by weight, mixed with stirring, dried and pulverized to produce a photocatalyst complex.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited by these Examples.

Example 1
After dispersing 135 g of tungsten oxide (Nippon Shin Metals Co., Ltd., 99.9%) having a particle diameter (median diameter: d50) of 45 to 50 μm in 1215 g of ion-exchanged water, a bead diameter of 0.1 mm (Nikkato) is used. Using a bead mill (Nippon Coke Industries, MSC50), the peripheral speed was 10 m / s, pulverization and dispersion were performed for 360 minutes to obtain a dispersion of tungsten oxide particles having a median diameter of 0.15 to 0.20 μm.

In the obtained dispersion of tungsten oxide particles, hexachloroplatinum (VI) hexahydrate (Kishida Chemical Co., Ltd.) was prepared so that the weight ratio of platinum alone to the weight of tungsten oxide particles was 0.025 wt%. , 98.5%) 2.5% of a 1% aqueous solution was added.
Thereafter, the dispersion is heated at 100 ° C. to evaporate water, and then calcined at 400 ° C. for 30 minutes to obtain tungsten oxide particles carrying 0.025% by weight of platinum (promoter). It was.

Water was added to the photocatalyst so as to have a solid content concentration of about 20% by weight, and commercially available high silica zeolite powder (Tosoh, HSZ) was added to 10 g of the obtained photocatalyst slurry so that the mixing ratio of high silica zeolite was 10% by weight. -891HOA, SiO ₂ / Al ₂ O ₃ ratio 1,500, crystalline ZSM-5 form) 0.22 g, stirred with a magnetic stirrer for 1 hour, dried and ground, visible light responsive photocatalyst-adsorption An agent complex was obtained.

Example 2
In Example 1, a visible light responsive photocatalyst-adsorbent complex was obtained in exactly the same manner as in Example 1, except that the mixing ratio of the high silica zeolite was 30% by weight.

Example 3
In Example 1, a commercially available high silica zeolite powder (Tosoh, HSZ-990HOA, SiO ₂ / Al ₂ O ₃ ratio 1,700, crystalline beta form) was used so that the mixing ratio of high silica zeolite was 20% by weight. A visible light responsive photocatalyst-adsorbent complex was obtained in the same manner as in Example 1 except that.

Example 4
A bead mill (manufactured by Nihon Coke Kogyo Co., Ltd.) was prepared in advance with a 10% by weight aqueous suspension of commercially available high silica zeolite powder (Tosoh, HSZ-891HOA, SiO ₂ / Al ₂ O ₃ ratio 1,500, crystalline ZSM-5 form). For 30 minutes, and add this pulverized high silica zeolite suspension to a 20% tungsten oxide dispersion so as to be 50% by weight with respect to the weight of tungsten oxide, and mix by stirring and drying. By grinding, a visible light responsive photocatalyst-adsorbent complex was obtained.

Example 5
In Example 4, a visible light responsive photocatalyst-adsorbent complex was obtained in exactly the same manner as in Example 4 except that the pulverization time was changed to 60 minutes when preparing the pulverized high silica zeolite suspension. It was.

Example 6
In Example 4, a visible light responsive photocatalyst-adsorbent complex was obtained in exactly the same manner as in Example 4 except that the pulverization time was changed to 90 minutes when preparing the pulverized high silica zeolite suspension. It was.

Comparative Example 1
In Example 1, a commercially available high silica zeolite powder (Tosoh, HSZ-390HUA, SiO ₂ / Al ₂ O ₃ ratio 500, crystal Y form) was used so that the mixing ratio of high silica zeolite was 10% by weight. In the same manner as in Example 1, a visible light responsive photocatalyst-adsorbent complex was obtained.

Comparative Example 2
In Example 1, commercially available high silica zeolite powder (Tosoh, HSZ-860NHA, SiO ₂ / Al ₂ O ₃ ratio 70, crystalline ZSM-5 form) was used so that the mixing ratio of high silica zeolite was 40% by weight. A visible light responsive photocatalyst-adsorbent complex was obtained in the same manner as in Example 1 except that.

Comparative Example 3
A visible light responsive photocatalyst-adsorbent complex was obtained in the same manner as in Comparative Example 2, except that the mixing ratio of high silica zeolite in Comparative Example 2 was 10% by weight.

Comparative Example 4
In Example 1, a visible light responsive photocatalyst was obtained in the same manner as in Example 1 except that high silica zeolite was not used.

Comparative Example 5
80 g of commercially available titanium dioxide powder (Kishida Kagaku, 99.5%) and 240 g of urea were mixed and calcined at 400 to 600 ° C. for 3 hours to obtain nitrogen-doped titanium oxide particles as a visible light responsive photocatalyst.

Comparative Example 6
In Example 4, a visible light responsive photocatalyst was prepared in the same manner as in Example 4 except that, during the preparation of the pulverized high silica zeolite suspension, the pulverization time was changed to 240 minutes and tungsten oxide was not used. An adsorbent not containing was obtained.
In addition, the change of the crystal structure depending on the grinding time of the high silica zeolite obtained by changing the grinding time when preparing the adsorbent in Comparative Example 6 is shown in FIG.

  Table 1 below shows the respective characteristics of the visible light responsive photocatalyst-adsorbent complex and the visible light responsive photocatalyst obtained in Examples 1 to 6 and Comparative Examples 1 to 6.

  Using the visible light responsive photocatalyst-adsorbent complex, the visible light responsive photocatalyst or the adsorbent obtained in Examples 1 to 6 and Comparative Examples 1 to 6, the adsorption / resolution tests of volatile organic compounds were modeled. Acetaldehyde was used as a compound.

Evaluation illuminance of visible light responsive photocatalyst-adsorbent complex Currently, the office hygiene standard rules stipulate that the illuminance is 300Lx or more in a place where precise work is performed and the illuminance is 100Lx or more in a place where ordinary work is performed. Has been.
In addition, the illuminance is 300 Lx between the eight tatami mats using two 30 W fluorescent lamps.
Furthermore, the illuminance in the room approximately 1 m from the indoor south window during a sunny day is usually 3,000 to 5,000 Lx, etc., and the following of the visible light responsive photocatalyst-adsorbent complex according to the present invention is as follows. The evaluation illuminance was set to 500 Lx and 1,000 Lx.

Oxidation resolution of acetaldehyde by visible light responsive photocatalyst-adsorbent complex or visible light responsive photocatalyst (acetaldehyde residual rate)
A visible light responsive photocatalyst-adsorbent complex or 10 mg of a visible light responsive photocatalyst was placed in a petri dish, the petri dish was placed in a 5 L gas bag, and acetaldehyde was introduced into the gas bag to a concentration of 300 ppm. .
Then, white LED (illuminance 1000Lx) was irradiated with respect to the gas bag, and the time-dependent change of the residual amount of acetaldehyde and the generation rate of a carbon dioxide were measured with the gas detector tube.
The following tables show the residual rate of acetaldehyde and the generation rate of carbon dioxide under irradiation of a white LED (illuminance 1000 Lx), respectively.

* The amount exceeding 100% is considered a measurement error.
Carbon dioxide production rate = carbon dioxide amount per hour (ppm) / (acetaldehyde injection amount (ppm) x 2)
Since acetaldehyde is a compound consisting of two carbon atoms, when acetaldehyde is completely oxidatively decomposed, carbon dioxide having a molar concentration twice that of the used acetaldehyde is theoretically generated.

From the above results, it was found that the disappearance rate of acetaldehyde by titanium dioxide of Comparative Example 5 was similar to that of the tungsten oxide simple substance of Comparative Example 4, but the amount of carbon dioxide generated was small.
This is because in the case of titanium dioxide according to Comparative Example 5, the activation of titanium dioxide by visible light is weaker than that of ultraviolet rays, so that acetaldehyde is not completely oxidatively decomposed, and acetic acid which is an intermediate in the process of oxidative decomposition of acetaldehyde. This is probably because the oxidative decomposition reaction stops at the methane, methanol, formaldehyde or formic acid stage.
In addition, as shown in Comparative Example 6, when high silica zeolite is pulverized with a bead mill, the adsorption performance is reduced due to the destruction of the crystal structure. Therefore, desired characteristics as a photocatalyst composite could be obtained by appropriately adjusting the grinding treatment time and the amount of high silica zeolite added.

Acceleration test evaluation test condition of repeated resolution of acetaldehyde by visible light responsive photocatalyst-adsorbent complex Test condition of 0.2 g of visible light responsive photocatalyst-adsorbent complex 10% by weight of HSZ-891HOA high silica zeolite according to Example 1 Into a 5 L gas bag containing 30 ppm acetaldehyde, irradiated with a white LED (illuminance 1000 Lx), and from the remaining amount of acetaldehyde present in the gas bag 24 hours later, a visible light responsive photocatalyst-adsorbent complex The deodorization rate (%) of acetaldehyde in the gas pack was calculated as the deodorization rate with respect to the initial concentration (30 ppm). As an acceleration test, acetaldehyde was added again to 30 ppm after 24 hours to the above used gas pack, and white LED (illuminance 1000 Lx) was irradiated and the deodorization rate was measured 24 hours later. It is shown in the following table.

  From the above results, it can be seen that the visible light responsive photocatalyst-adsorbent complex according to the present invention oxidatively decomposes 90% or more up to the 8th test even when an accelerated test in which 30 ppm of acetaldehyde is repeatedly added is performed. It has been found that the visible light responsive photocatalyst-adsorbent complex according to the invention can maintain its effect sufficiently even in such a severe test that it cannot be used normally.

  Since the visible light responsive photocatalyst-adsorbent complex of the present invention has a high adsorption ability of a volatile organic compound and a high decomposition ability by a visible light responsive photocatalyst, wallpaper, wallpaper adhesive, wall paint, Can be used for a long time by adding to carpets, filters, etc. It can also be provided in a container as a deodorant indoors.

Claims (12)

  A visible light responsive photocatalyst-adsorbent complex characterized in that tungsten oxide and high silica zeolite are complexed. The visible light responsive photocatalyst-adsorbent complex according to claim 1, wherein the adsorbent is high silica zeolite having a SiO ₂ / Al ₂ O ₃ composition ratio of 1200 to 2200.   The visible light responsive photocatalyst-adsorbent complex according to claim 1 or 2, wherein the adsorbent has a beta or ZSM-5 crystal form.   The visible light responsive photocatalyst-adsorbent complex according to any one of claims 1 to 3, wherein the adsorbent is hydrogen type high silica zeolite.   The visible light responsive photocatalyst-adsorbent complex according to any one of claims 1 to 4, wherein the adsorbent has a pore diameter of 5 mm or more and less than 7 mm.   The visible light responsive photocatalyst-adsorbent complex according to any one of claims 1 to 5, wherein the tungsten oxide has a primary particle size of 5 to 100 nm.   The visible response photocatalyst-adsorbent complex according to any one of claims 1 to 6, wherein the high silica zeolite is added in an amount of 10 to 80% by weight based on the weight of the tungsten oxide.   The visible light responsive photocatalyst-adsorbent complex according to any one of claims 1 to 6, wherein the visible light responsive photocatalyst further supports a cocatalyst.   The visible light responsive photocatalyst-adsorbent complex according to claim 8, wherein the cocatalyst is platinum, palladium or copper, a halide, an oxide, a hydroxide or a salt thereof.   The visible light responsive photocatalyst-adsorbent complex according to claim 8 or 9, wherein the promoter is added in an amount of 0.01 to 3% by weight based on the weight of tungsten oxide.   The visible light responsive photocatalyst-adsorbent complex according to any one of claims 1 to 10, wherein the visible light responsive photocatalyst-adsorbent complex adsorbs and decomposes a causative substance of sick house syndrome or malodor in the home. body.   12. The causative substance is one or more compounds included in the group consisting of formaldehyde, acetaldehyde, formic acid, acetic acid, toluene, xylene, trimethylbenzene, ethylbenzene, ammonia, amine, mercaptan, hydrogen sulfide, and isovaleric acid. Visible light-responsive photocatalyst-adsorbent complex described in 1.