JP2775399B2 - Porous photocatalyst and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous photocatalyst used as an environmental purification material for removing bad smells and harmful substances in the air, or treating wastewater and water, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, odors in living and working spaces and pollution by harmful substances such as exhaust gas from automobiles have become serious problems. Water pollution from domestic wastewater and industrial wastewater, especially water pollution from organic chlorine-based solvents and pesticides at golf courses, etc., which are difficult to treat with the current water treatment methods such as activated sludge, is widespread. Environmental pollution is becoming a serious social problem.

Hitherto, as a method of preventing odors or a method of removing harmful substances in the air, a method of absorbing or adsorbing to an absorbing solution such as an acid or an alkali, an adsorbent, soil, etc. is often performed. Treatment of waste liquor, used adsorbents and soil can cause secondary pollution. Also,
There are methods to mask odors using fragrances and methods to decompose with activated sludge or ozone.However, in the case of fragrances, there is a problem of contamination due to the odor of the fragrance itself. The ability is low, and the emission of sludge odor is inevitable,
Ozone has the disadvantage that it is toxic and costly (for example, Konosuke Nishida, Heibonsha "Large Encyclopedia")
Volume 1, p136 (1984)).

When a semiconductor is irradiated with light, electrons having a strong reducing action and holes having a strong oxidizing action are generated, and molecular species in contact with the semiconductor are decomposed by the redox action. By utilizing such an action of a semiconductor, that is, a photocatalytic action, it is possible to decompose and remove environmental pollutants such as organic solvents, pesticides, and surfactants dissolved in water and harmful substances in the air. This method only utilizes semiconductors and light, and has less restrictions on reaction conditions such as temperature, pH, gas atmosphere, toxicity, and the like, and is difficult to process using a biological treatment method, as compared to methods such as biological treatment using microorganisms. It has the advantage of being able to easily decompose and remove even compounds such as organic halogen compounds and organic phosphorus compounds. However, semiconductor powders have been used as a photocatalyst in research on decomposition and removal of organic substances by a photocatalyst (for example, see AL Pruden and DF Ollis, Journal of Cat.
alysis, Vol. 82, 404 (1983), H. Hidaka, H. Jou, K.
Nohara, J. Zhao, Chemosphere, Vol. 25, 1589 (199
2), Kusunaga Teruaki, Harada Kenji, Tanaka Keiichi, Industrial Water, No. 379
No. 12, (1990)). Therefore, it is difficult to handle and use as a photocatalyst.In the case of water treatment, the treated water must be filtered to recover the photocatalyst powder.However, since the photocatalyst is a fine powder, clogging may occur. However, there is a problem that it is difficult to separate and recover the treated product and the photocatalyst, and it is not possible to continuously treat water.

[0005]

SUMMARY OF THE INVENTION In view of the above, the present invention enables continuous removal of odors and harmful substances in the air, wastewater treatment, water purification treatment, and the like. Excellent decomposition removal effect and its persistence,
Moreover, it is an object of the present invention to provide a porous photocatalyst having excellent characteristics in terms of economy, safety, weather resistance and stability, and a method for producing the same.

[0006]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies, and as a result, coated a titania sol to which polyethylene glycol or polyethylene oxide was added on the surface of a porous body, and then baked by heating. The porous photocatalyst produced by this method has pores with uniform pore size on the surface, efficiently adsorbs organic compounds contaminating the environment such as organic solvents and pesticides dissolved in water, and irradiates light. The present inventors have found that the redox effect of electrons and holes generated by the above-mentioned method allows rapid decomposition and removal, and that the effect can be maintained without maintenance, and the present invention has been accomplished.

As the porous material used in the present invention, various materials such as porous ceramics, glass, and metal can be used.
Activated alumina and silica gel are particularly preferred.

The shape of the porous body used in the present invention may be any shape such as a granular shape, a plate shape, a cylindrical shape, a prism shape, a conical shape, a spherical shape, a gourd shape, and a rugby ball shape.

The titania sol used in the present invention is obtained by suspending ultrafine titanium oxide in water or hydrolyzing an alkoxide of titanium obtained by reaction of alcohol with titanium tetrachloride or titanium metal. Prepared. At that time, monoethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N,
When alcohol amines such as N-dimethyldiaminoethanol and diisopropanolamine and glycols such as diethylene glycol are added, a uniform and transparent titania sol is obtained, and by using the same, a high-performance porous photocatalyst can be produced.

The porous photocatalyst of the present invention is prepared by adding polyethylene glycol or polyethylene oxide to the thus obtained titania sol, coating the surface of the porous body by a dip coating method, a dropping method, a coating method, a spraying method, and the like, and then heating. It is obtained by firing. Here, when polyethylene glycol or polyethylene oxide is not added to the titania sol,
Pores on the surface of the porous body are covered with titanium oxide, and a porous photocatalyst having a large specific surface area cannot be obtained. By adding polyethylene glycol or polyethylene oxide to the titania sol, the polyethylene glycol or polyethylene oxide burns and disappears when heated and baked, so pores are opened in the surface of the porous body and connected to the pores, and a porous photocatalyst with a large specific surface area Is obtained.

[0011] In this case, the method of firing is to raise the temperature gradually from room temperature to the final temperature of 600 ° C to 700 ° C, or to perform firing at a temperature of 400 ° C to 600 ° C. Is desirable. By this operation, the titania sol coated on the surface of the porous body is changed into titanium oxide whose crystal form is anatase, which has high performance as a photocatalyst. At this time, firing is performed directly at a temperature of 600 ° C. to 700 ° C., the firing temperature is lower than 400 ° C.,
If the temperature is higher than ° C, only low-activity rutile or amorphous titanium oxide can be obtained as a photocatalyst.

In the porous photocatalyst of the present invention, in order to obtain a strong and high-performance titanium oxide film in which the titanium oxide film is strongly adhered to the porous material, a titania sol to which polyethylene glycol or polyethylene oxide is added is thinly coated or sprayed on the porous material. Alternatively, it is preferable to form a titanium oxide thin film on the surface of the porous body by heating and baking it after coating, and to form a multilayer film on the surface of the porous body by repeating this operation. When the porous material is activated carbon or the like, it is desirable to use a material whose surface has been made hydrophilic by previously treating the porous material with an acid such as nitric acid, sulfuric acid, or hydrochloric acid. By doing so, the titanium oxide film is firmly bonded to the surface and a high-performance porous photocatalyst that is strong and durable can be obtained.

[0013] The polyethylene glycol or polyethylene oxide to be added to the titania sol used in the present invention preferably has a molecular weight of 1,000 or more.
000, 6000, 8000, 11000, 1300
Those having 0, 20,000, 100,000, 300,000, 2,000,000, and 2.5 million are preferable. When the molecular weight is less than 1000, the titanium oxide film formed on the surface of the porous body is easily peeled off from the porous body, and it is possible to obtain a high-performance porous photocatalyst that is strong and durable. Can not.

The amount of polyethylene glycol or polyethylene oxide added to the titania sol used in the present invention is preferably not more than its solubility. When added in excess of the solubility, pores having a uniform pore size cannot be formed, and a titanium oxide film which is durable and excellent in durability cannot be formed.

The size of the pore diameter and the density of the pore distribution on the surface of the porous photocatalyst of the present invention can be controlled by changing the amount of polyethylene glycol or polyethylene oxide added or the molecular weight. If the addition amount is reduced or a small molecular weight is used, a porous photocatalyst with small pores on the surface increases the addition amount,
When a polymer having a large molecular weight is used, a porous photocatalyst having large pores can be obtained. And when the addition amount is small, a porous photocatalyst having a sparse distribution of pores,
When the addition amount is large, a porous photocatalyst having a dense pore distribution can be obtained. When polyethylene glycol or polyethylene oxide having a wide molecular weight distribution is added, a porous photocatalyst having pores of various pore sizes on the surface can be obtained. Furthermore, by laminating thin films, a porous photocatalyst having a unique three-dimensional structure can be obtained.

In order to further enhance the performance of the porous photocatalyst of the present invention, the surface thereof may be coated with a metal film of platinum, rhodium, ruthenium, palladium, silver, copper, zinc or the like. As a method of coating these metal films on the surface,
Examples include a photoelectrodeposition method, a CVD method, and a PVD method such as sputtering or vacuum deposition. In this case, if the thickness of the metal film is too large, the cost increases, and light hardly reaches the titanium oxide thin film. Therefore, it is preferable that the thickness of the metal film is as thin as possible.

The thus obtained porous photocatalyst according to the present invention is porous and has a large specific surface area.
Efficiently adsorbs harmful substances in the air such as Ox, organic solvents dissolved in water, and organic compounds contaminating the environment such as agricultural chemicals, sunlight, fluorescent lights, incandescent lights, black lights, UV lamps, It can be rapidly and continuously decomposed and removed by the redox action of electrons and holes generated in the titanium oxide thin film on the surface by irradiation of artificial light from a mercury lamp, xenon lamp, halogen lamp, metal halide lamp, or the like. Moreover, by adjusting the pore diameter of the pores on the surface of the porous photocatalyst to the size of the molecule of the environmental pollutant, it can be more efficiently adsorbed and decomposed and removed. The porous photocatalyst according to the present invention can be used at low cost, energy saving and maintenance-free only by irradiating light, and a metal such as platinum or rhodium, ruthenium, palladium, silver, copper, zinc is formed on the titanium oxide film. When the film is coated, its catalytic action further enhances the effect of decomposing and removing organic compounds. In this case, since the photocatalyst is porous, the metal is well dispersed and covers the photocatalyst, so that the catalytic action of the metal can be particularly effectively brought out.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Among the embodiments of the present invention, particularly representative ones will be described below.

Example 1 Titanium tetraisopropoxide (60 g) was diluted with 500 ml of absolute ethanol, and while stirring, 20 g of diethanolamine and 5 g of water were added, and 5 g of polyethylene glycol having a molecular weight of 1,000 was further added to form a transparent sol solution. The titanium oxide film was prepared and coated on a surface of an activated carbon honeycomb having a size of 8 cm square and a thickness of 2 cm by a dip coating method. That is, the activated carbon honeycomb was immersed in the sol solution, pulled up, dried, and fired at a temperature of 450 ° C., and repeated five times to form a titanium oxide film on the surface of the activated carbon honeycomb. The crystal structure of the obtained titanium oxide film was examined by X-ray diffraction.
Met. When the surface was observed with an electron microscope, it was found to be covered with pores having a size of about 10 nm. NOx was decomposed and removed using this porous photocatalyst. First, the obtained porous photocatalyst is placed in a closed container having an internal volume of 40 l in which a commercially available incandescent lamp of 100 W is set.
After 10 ppm of NOx was introduced by syringe, the incandescent lamp was turned on. After one hour, NO contained in the air in the closed container
The concentration of x was measured using a gas chromatograph, and the reduced amount of NOx was injected. This operation was repeated every hour. As a result, when the porous photocatalyst was used, NOx was removed and the concentration was reduced to almost 0 ppm each time. On the other hand, when the activated carbon honeycomb was used instead of the porous photocatalyst, the concentration of NOx was almost 0 ppm at the first time, but as the number of times increased, the concentration gradually increased, and after 8 times, The starting value was 10 ppm.

Example 2 45 g of titanium tetraisopropoxide was diluted with 400 ml of absolute ethanol, and while stirring, 15 g of triethanolamine and 4 g of water were added.
Was added to prepare a transparent sol solution, and a titanium oxide film was coated on the surface of a spherical silica gel having a diameter of about 3 mm by a dropping method. That is,
A small amount of this sol solution was dropped on the surface of the spherical silica gel, excess liquid was dropped and dried.
, And baked by heating to a temperature of 5 ° C., and this was repeated five times to form a titanium oxide film on the surface of the spherical silica gel. As a result of examining the crystal structure of the obtained titanium oxide film by X-ray diffraction, it was found to be 100% anatase. When the surface was observed with an electron microscope, it was found to be covered with pores having a size of about 20 nm. Using this porous photocatalyst, the malodorous substances were decomposed and removed. First, 50 g of the obtained porous photocatalyst was spread in a closed container having an inner volume of 30 L in which a commercially available 100 W black light was set, and 80 ppm of trimethylamine as a malodorous substance was introduced with a syringe, and then the black light was turned on. . After 30 minutes, the concentration of trimethylamine contained in the air in the closed container was measured using a gas chromatograph, and the reduced amount of trimethylamine was injected. As a result of repeating this operation every 30 minutes, when a porous photocatalyst was used, trimethylamine was decomposed and the concentration was reduced to almost 0 ppm each time.
On the other hand, when spherical silica gel was used instead of the porous photocatalyst, the first time the concentration of trimethylamine was reduced to zero.
Although the concentration was close to ppm, the concentration gradually increased as the number of times was increased, and after 10 times, the concentration was 80 ppm, which was the starting value.

Example 3 20 g of titanium tetrabutoxide was diluted with 150 ml of t-butyl alcohol, and while stirring, 7 g of triethanolamine and 1.5 g of water were added.
A transparent sol solution was prepared by adding 0.1 g of polyethylene oxide, and a titanium oxide film was coated on the surface of spherical activated alumina having a diameter of 6 mm by a coating method. That is, this sol solution is thinly applied to the surface of the spherical activated alumina with a brush, dried, heated and gradually heated from room temperature to a temperature of 700 ° C., and baked. A titanium oxide film was formed on the surface. Observation of the surface of the obtained titanium oxide film with an electron microscope revealed that the surface was covered with pores having a size of about 1200 nm. Using the obtained porous photocatalyst, acetic acid as a malodorous substance was decomposed and removed. First, 40 g of the obtained porous photocatalyst was spread in a sealed container having an internal volume of 60 l in which 10 commercially available 20 W fluorescent lamps were set, and 90 ppm of acetic acid was introduced with a syringe, and then the fluorescent lamp was turned on. One hour later, the concentration of acetic acid contained in the air in the closed container was measured using gas chromatography, and the reduced amount of acetic acid was injected. As a result of repeating this operation every hour, when a porous photocatalyst was used, acetic acid was decomposed and the concentration was almost 0 ppm each time.
Was decreasing. On the other hand, when spherical activated alumina was used in place of the porous photocatalyst, the concentration of acetic acid was close to 0 ppm at the first time, but as the number of times increased, the concentration gradually increased, and after 15 times, The starting value was 90 ppm.

Example 4 200 g of titanium tetraethoxide (25 g) was diluted with methanol, and while stirring, 8 g of N-methyldiethanolamine and 2 g of water were added, and 0.1 g of polyethylene oxide having a molecular weight of 100,000 was further added. A sol solution is prepared, and the width is 5 cm, the length is 10 cm, and the thickness is 4 by a coating method.
Activated carbon cloth was coated with a titanium oxide film. That is, this sol solution is thinly applied to the surface of an activated carbon cloth treated with a 15% hydrochloric acid aqueous solution heated to 70 ° C., dried, and then heated and fired to a temperature of 470 ° C. Made a titanium oxide film on the surface of the cloth. As a result of examining the crystal structure of the obtained titanium oxide film by X-ray diffraction, it was found to be 100% anatase. The surface was observed with an electron microscope.
It was covered with pores of nm size. The obtained porous photocatalyst was used to decompose trichlorethylene, which is widely used as a solvent and a cleaning agent in the high-tech industry and the cleaning industry, and has become a problem by contaminating groundwater and soil. 1
15 ml of an aqueous solution of trichlorethylene having a concentration of 0 ppm
Is placed in a quartz glass test tube, and a porous photocatalyst 1 is placed therein.
After immersion in 0 g and bubbling of oxygen, light from a 500 W high-pressure mercury lamp was applied. One hour later, the amount of trichlorethylene contained in the reaction solution was measured using a gas chromatograph, and a reduced amount of an aqueous solution of trichlorethylene was added. This operation was repeated every hour. As a result, when a porous photocatalyst was used, trichloroethylene was decomposed and the concentration was reduced to almost 0 ppm each time. On the other hand, when activated carbon cloth was used instead of the porous photocatalyst, the concentration of trichlorethylene was almost 0 ppm at the first time.
However, as the number of times was increased, the concentration gradually increased, and after 11 times, the starting value was 10 ppm.

Example 5 Titanium tetraisopropoxide (30 g) was diluted with 200 ml of isopropanol, and while stirring, diisopropanolamine (10 g) and water (2 g) were added.
0.4 g of polyethylene glycol was added to prepare a transparent sol solution, and the diameter was 2 mm and the length was 3
A titanium oxide film was coated on the surface of granular silica gel having a thickness of 1 mm. In other words, the sol liquid is sprayed while shaking the granular silica gel on a fine wire mesh, dried, and then heated from room temperature to 620 ° C., and then baked. A titanium oxide film was made. As a result of examining the crystal structure of the obtained titanium oxide film by X-ray diffraction, it was found to be 100% anatase. The surface was observed with an electron microscope.
It was covered with pores of nm size. This porous photocatalyst was used to decompose tetrachloroethylene, which is currently widely used as a solvent and a cleaning agent in the high-tech industry and the cleaning industry, and has become a problem by contaminating groundwater and soil. 10 ml of an aqueous solution of tetrachloroethylene having a concentration of 10 ppm was placed in a test tube made of hard glass, 12 g of the obtained porous photocatalyst was immersed therein, oxygen was bubbled therein, and irradiation with a 300 W xenon lamp was performed. Two hours later, the amount of tetrachloroethylene contained in the reaction solution was measured using a gas chromatograph, and a reduced amount of an aqueous solution of tetrachloroethylene was added. This operation was repeated every two hours. As a result, when a porous photocatalyst was used, tetrachloroethylene was decomposed and the concentration was almost 0 ppm each time.
Was decreasing. On the other hand, when granular silica gel was used in place of the porous photocatalyst, the granular silica gel was broken into pieces, and the concentration of tetrachloroethylene hardly changed from the initial value.

Example 6 14 g of titanium tetraisopropoxide was diluted with 100 ml of absolute ethanol, and while stirring, 5 g of N-ethyldiethanolamine and 1 g of water were added.
1 g of polyethylene glycol was added to prepare a transparent sol solution, and the diameter was 2 mm and the length was 3 mm by a dropping method.
The surface of the granular activated carbon was coated with a titanium oxide film. That is, a small amount of this sol solution is dropped on the surface of granular activated carbon treated with a 10% aqueous nitric acid solution heated to 80 ° C., excess liquid is dropped and dried, and then heated and fired at 480 ° C. Six times, a titanium oxide film was formed on the surface of the granular activated carbon. The crystal structure of the obtained titanium oxide film was examined by X-ray diffraction.
Met. When the surface was observed with an electron microscope, it was found to be covered with pores having a size of about 50 nm. Using this porous photocatalyst, acetic acid was decomposed. 20 ppm
Was placed in a quartz container, 5 g of the obtained porous photocatalyst was immersed in the container, and oxygen was bubbled therein, followed by irradiation with light from a 200 W mercury lamp. One and a half hours later, the amount of acetic acid contained in the obtained reaction solution was measured using a gas chromatograph, and a reduced amount of an aqueous solution of acetic acid was added. This operation was repeated every hour and a half. As a result, when the porous photocatalyst was used, acetic acid was decomposed and the concentration was reduced to almost 0% each time. On the other hand, when granular activated carbon was used in place of the porous photocatalyst, the concentration of acetic acid was almost 0 ppm at the first time, but as the number of times increased, the concentration gradually increased, and after 9 times, Is 20pp
m and the starting value.

Example 7 Titanium tetrabutoxide (20 g) was diluted with 150 ml of t-butyl alcohol, and while stirring, triethanolamine (7 g) and water (1.5 g) were added.
0.1 g of polyethylene oxide was added to prepare a transparent sol solution, and a titanium oxide film was coated on the surface of 5 mm-diameter spherical activated alumina by a spray method.
That is, after spraying the sol solution while shaking the spherical activated alumina on the fine wire mesh, the sol solution is dried,
The temperature was gradually increased from room temperature to 650 ° C., followed by firing, and this was repeated six times to form a titanium oxide film on the surface of the spherical activated alumina. As a result of examining the crystal structure of the obtained titanium oxide film by X-ray diffraction, it was found to be 100% anatase. When the surface was observed with an electron microscope, it was found to be covered with pores having a size of about 800 nm. This was immersed in a 2 g / l aqueous solution of potassium chloroplatinate in ethanol, and stirred with a magnetic stirrer for 100
Light from a W mercury lamp was irradiated for 1 hour, and the surface of the titanium oxide film was coated with platinum by a photoelectric deposition method. Using the obtained porous photocatalyst, 4-nitrophenylethylphenylphosphinate, which is an organic phosphorus-based pesticide, was decomposed. 10
200 ml of an aqueous solution of 4-nitrophenylethylphenyl phosphinate having a concentration of 0 ppm was put into a 300 ml quartz beaker, 10 g of the obtained porous photocatalyst was immersed therein, and oxygen was bubbled thereinto. Irradiated. Two hours later, the amount of 4-nitrophenylethylphenyl phosphinate contained in the obtained reaction solution was measured using a gas chromatograph.
An aqueous solution of -nitrophenylethylphenylphosphinate was added. This operation was repeated every two hours. As a result, when a porous photocatalyst was used, 4-nitrophenylethylphenylphosphinate was decomposed and the concentration was reduced to almost 0% each time. On the other hand, when spherical activated alumina was used instead of the porous photocatalyst, the first
The concentration of -nitrophenylethylphenyl phosphinate was almost 0 ppm, but as the number of times increased, the concentration gradually increased, and after 10 times, the initial value was 100 ppm. Note that a porous photocatalyst coated with a metal film such as rhodium, ruthenium, palladium, silver, copper, or zinc instead of platinum also showed high decomposition activity.

[0026]

As described above, the present invention has the ability to decompose and remove environmental pollutants such as malodorous substances in the air and organic compounds dissolved in water, as well as the effect of preventing the growth of bacteria and mold, and its sustainability. It is an object of the present invention to provide a porous photocatalyst having excellent properties and excellent properties in terms of economy, safety, water resistance, heat resistance, light resistance, weather resistance, and stability, and a method for producing the same. The titanium oxide used in the present invention is also used in paints, cosmetics, toothpastes, etc., and has many advantages such as excellent weather resistance and durability, non-toxicity and safety. Therefore, the porous photocatalyst according to the present invention, in which the porous body is coated with titanium oxide, has improved defects even when the porous body of the substrate is weak to water such as silica gel, and has water resistance, weather resistance, durability and the like. Shows excellent characteristics. In addition, the porous photocatalyst according to the present invention is capable of generating an unpleasant odor, NOx, and SOx by the redox effect of electrons and holes generated in the titanium oxide film by receiving external light such as an electric lamp or sunlight.
Decomposes harmful substances in the air such as x or organic compounds that are polluting the environment such as organic solvents or pesticides dissolved in water, but when the concentration of environmental pollutants is low because the photocatalyst is porous However, the adsorption allows rapid and effective decomposition and removal. Moreover, compared to conventional methods such as ozone treatment, no toxic substances such as ozone are used, and only light irradiation is required, and light or natural light may be used. It is maintenance-free and can be used for a long time. In addition, if the porous photocatalyst is coated with platinum, rhodium, ruthenium, palladium, silver, copper, zinc, or the like, the catalytic action further increases the decomposition and removal effect and maintains the effect without maintenance.

Furthermore, the porous photocatalyst according to the present invention is effective not only for deodorization in the interior of a car, in a living room, a kitchen, and a toilet, treatment of wastewater, purification of pools and stored water, but also effective prevention of the growth of bacteria and mold. It can be applied to a wide range of applications such as And platinum and rhodium on the titanium oxide film,
When coated with a metal film of ruthenium, palladium, silver, copper, zinc, etc., the metal film has an antibacterial and antifungal effect due to its catalytic action, effectively preventing the growth of bacteria and mold on the film. can do.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B01J 23/42 B01J 23/46 301A 23/44 311A 23/46 301 23/50 A 311 23/72 A 23/50 35/02 J23 / 72 B01D 53/36 J35 / 02 G102B (56) References JP-A-5-58604 (JP, A) JP-A-63-248443 (JP, A) JP-A-6-293519 (JP, A) JP-A-3-157125 (JP, A) JP-A-5-96180 (JP, A) JP-A-4-83537 (JP, A) JP-A-7-51646 (JP, A) JP-A-3 -193679 (JP, A) JP 6-102155 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) B01J 21/00-38/00 A61L 9/00 B01D 53/86 -53/96 C01G 23/04

Claims (11)

(57) [Claims] 1. The method of claim 1 , wherein the diameter of the pores is 5 nm to 2 μm at the time of manufacture.
A porous photocatalyst, characterized in that the surface of a porous body is coated with a titanium oxide film having pores of uniform pore size adjusted to an arbitrary size within a range . 2. The method according to claim 1 , wherein said fine pores have a diameter of 5 nm to 2 μm at the time of manufacture.
After covering the surface of the porous body with a titanium oxide film having pores with uniform pore diameters adjusted to an arbitrary size in the range , the surface is platinum, rhodium, ruthenium, palladium, silver,
A porous photocatalyst characterized by being coated with at least one metal film selected from copper and zinc. 3. The porous photocatalyst according to claim 1, wherein the porous body is at least one selected from activated carbon, activated alumina, and silica gel. 4. The surface of the porous body is adjusted for the distribution and pore size of the pores.
Any density at the time of manufacture and any in the range of 5 nm to 2 μm
Oxidized titanium with pores of uniform pore size adjusted to size
A porous photocatalyst characterized by being coated with a tan film. 5. The porous photocatalyst according to claim 1, wherein the crystalline form of the titanium oxide porous thin film is anatase. 6. A titania sol prepared from an alkoxide of titanium and alcohol amines or glycols,
A method for producing a porous photocatalyst coated with a titanium oxide film having pores with uniform pore diameters, comprising adding polyethylene glycol or polyethylene oxide, coating the surface of the porous body, and then heating and calcining the porous body. 7. A titania sol prepared from an alkoxide of titanium and an alcoholamine or glycol,
Polyethylene glycol or polyethylene oxide is added, coated on the surface of the porous body, heated and baked, and the surface is coated with at least one metal film selected from platinum, rhodium, ruthenium, palladium, silver, copper, and zinc. A method for producing a porous photocatalyst coated with a titanium oxide film having pores of uniform pore size, characterized by being coated with a titanium oxide film. 8. The method for producing a porous photocatalyst according to claim 6, wherein the porous body is at least one selected from activated carbon, activated alumina, and silica gel. 9. The method for producing a porous photocatalyst according to claim 6, wherein a polyethylene glycol or polyethylene oxide having a molecular weight of 1,000 or more is used. 10. The method for producing a porous photocatalyst according to claim 6, wherein the amount of polyethylene glycol or polyethylene oxide added to the titania sol is not more than its solubility. 11. The method for producing a porous photocatalyst according to claim 6, wherein the surface of the porous body is treated to be hydrophilic with an acid.