WO2004041431A1 - Method of roll-forming photocatalyst or the like on sphere - Google Patents

Abstract

A method of roll-forming a photocatalyst, comprising the steps of forming a film of silicone binder having a predetermined film thickness on the surface of a sphere by a film forming means, uniformly sticking a photocatalyst thereto in film form while the silicone binder is in its uncured state by using a pan type rolling device or planetary-motion-utilizing rolling device, ball screw device, vibration-rolling device or the like, immersing the same in water, forcibly degassing the organic matter in the silicone sealant and causing the silicone oil to ooze out while washing away an excess photocatalyst, processing the organic matter in the water with photocatalyst powder dispersed in the water by photoexcitation of the photocatalyst by ultraviolet rays, decomposing the organic matter on the photocatalyst surface by the photocatalyst sticking to the sphere surface, so as to form a hydrophilic layer on the photocatalyst surface, thereby mass-producing a pure photocatalyst having a large surface area.

Description

 Specification

 Rolling molding method of photocatalyst etc. into a sphere

 The present invention relates to a method for rolling a photocatalyst and a photocatalyst produced by this method. Background art

 To date, various methods for producing photocatalysts have been proposed. For the conventional photocatalyst, a wet method such as a method of forming from a titanium dioxide precursor such as titanium alkoxide by a sol-gel method, and a dry method such as sputtering, vapor deposition, and ion plating have been proposed. For example, the wet method is generally formed through a firing step as a post-treatment. As an example of this, Japanese Patent No. 30385999 relates to a photocatalyst supporting structure, and Japanese Patent Application Laid-Open No. H10_34143 discloses a method of mixing titanium oxide and iron oxide powder. Japanese Patent Application Publication No. JP-A-2003-7-12881 describes a composite metal oxide and a method for producing the same, and Japanese Patent Application Laid-Open No. 11-1269725 discloses a photocatalytic activity. A method for producing a thin film having the same is disclosed. Disclosure of the invention

However, the above-mentioned dry method has problems that the equipment cost is high and the time required for film formation is relatively long, which is not preferable in terms of productivity. Although there is no such problem in the wet method, the sol-gel method uses a metal organic compound solution as a starting material, and hydrolyzes and polymerizes the compound in the solution to form a metal oxide or a metal oxide. The sol in which the fine particles of the hydroxide are dissolved is further reacted, and the amorphous porous gel formed by gelation is heated to form a crystalline body. This is a complex process that involves a complex scientific process and a firing process to fix the photocatalytic oxide on the substrate surface.Thus, titanium dioxide is anatase-type around 525 ° C during firing. To rutile-type titanium oxide, and the catalytic ability may decrease. In addition, the sol and gel processes involve complex scientific treatments, resulting in high production costs and an obstacle to market penetration. SUMMARY OF THE INVENTION The present invention has been made to meet the above-mentioned demands, and an object of the present invention is to provide a rolling device using a pan-type rolling device or a planetary motion, a poll screw device, a vibration rolling device, and the like. The photocatalyst powder is uniformly adhered to the surface of the substrate in the form of a film via a binder, and the silicone binder is treated at room temperature without heat treatment so that the photocatalyst and silicone binder fixed on the surface have a high degree of hydrophilicity. An object of the present invention is to provide a photocatalytic rolling molding method for producing a large amount of pure photocatalyst having a large surface area.

 In addition, in the process of imparting hydrophilicity in water, the organic matter mixed in the silicone binder is not vaporized, and the organic matter coming out of the binder is decomposed by using a photocatalytic reaction in water by irradiating ultraviolet light without vaporizing it. An object of the present invention is to provide a method for rolling a photocatalytic sphere while producing the same. The present invention has the following means to solve the above problems.

 In order to achieve the first object of the present invention, a silicone binder is formed on a surface of a sphere to a predetermined thickness by a film forming means, and then the photocatalyst powder is applied while the silicone binder is not yet cured. Then, while washing the excess photocatalyst in water vapor or hot water, organic substances coming out of the binder are decomposed by photoexcitation of the photocatalyst by ultraviolet rays, and a hydrophilic layer is formed on the surface of the photocatalyst sphere. Then, the photocatalyst particles were held in an exposed state.

Using a rolling device that rolls a drum, a pole screw rolling device, and a vibrating rolling device as film forming means, the sphere is rotated to form a film while supplying a predetermined amount of a silicone binder to the surface of the sphere. A rolling device that rolls a drum, a ball screw rolling device, or a vibrating rolling device is used as a coating unit, and the drum is rotated to apply a predetermined amount of silicone binder to the surface of the sphere.

 Further, after the silicone binder is formed on the surface of the sphere, the sphere and the photocatalyst powder are charged along a linear or spiral inclined guide surface, and the photocatalyst powder is applied to the sphere surface while rolling by its own weight. Let it adhere.

In order to achieve the object of the present invention, a titanium dioxide powder, a mixed powder of titanium dioxide and iron oxide, a mixed powder of titanium dioxide and iron oxide, and a carbide are used as the photocatalyst. Charcoal, bamboo charcoal or activated carbon is used as the charcoal. The outstanding adsorption action of the carbide, water, or chlorine floating in the atmosphere, harmful organic substances such as N0 _X aspirated captured, the decomposition treatment to pollution-free organic matter by photocatalyst such as titanium oxide Aim. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a longitudinal sectional view showing the upper surface of the planetary rolling device.

 FIG. 2 is a longitudinal sectional view showing a side surface of the planetary rolling device.

 FIG. 3 is a longitudinal sectional view showing a side surface of the pawl screw rolling device.

 FIG. 4 is a longitudinal sectional view showing the front of the vibration rolling device.

 FIG. 5 shows the change in absorbance over time of the methylene blue absorbance test for the titanium oxide coat ceramic pole of Experimental Example 1 in the first example.

 FIG. 6 shows a change in absorbance over time in a methylene blue absorbance test with respect to a change in temperature of a ceramic pole coated with a mixed powder of titanium oxide and iron oxide of Experimental Example 2 in the first example.

Fig. 7 shows the effect of ultraviolet light on the coated ceramic balls of the mixed powder of titanium oxide and iron oxide of Experimental Example 3 in the first embodiment. The test shows the change in absorbance over time.

 Figure 8 is a scanning electron micrograph of the surface of a titanium oxide-coated ceramic ball.

 FIG. 9 shows the change in absorbance of the bamboo charcoal-coated ceramic balls of the second example over time in the methylene blue absorbance test with respect to the effect of ultraviolet light.

 Figure 10 is a photograph of an adsorption-decomposition type photocatalyst in which titanium oxide is coated on bamboo charcoal, and shows how titanium oxide adheres to bamboo charcoal on the ground.

 The reference numerals given in these figures represent the following, respectively.

 1 0: 虽 虽 虽

 1 1:

 1 1a: Motor

 1 2: Pinion gear

 1 3: Drive gear

 14: Table

 15: Cylindrical container

 1 9: Hopper

 20: Ball screw

 2 1: U-shaped trough

 2 2: SCREEN

 2 3: Bearing

 2 4: Bearing

2 5: Coupling Best mode for carrying out the invention Hereinafter, specific embodiments of the present invention will be described in detail, but the present invention is not limited to these disclosed embodiments.

Ceramic pole as a sphere, the mechanical strength by using the well thermal expansion coefficient is small stable mullite _{(3AL 2 0 3 · 2Si0 2} ), and as the silicone by Sunda one, using silicone sealant material. The base of the sphere was previously treated with a primer.

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

 (First embodiment)

 The rolling device of this embodiment uses a planetary gear, and uses a planetary motion device that gives revolution and rotation. The rolling device uses a base 1 1 as shown in FIGS. 1 and 2 illustrating the principle. The table 14 is driven via the motor 1 la, the pinion gear 1 2 and the drive gear 1 3 installed on the table 1 and consists of three cylindrical drums 15 fixed to the table 14. When a ceramic pole is put into the bowl and a silicone sealant is injected to give rotational movement, the pole rolls and applies silicone sealant so that it is evenly applied to a thickness of about 0.1 mm. The amount of silicone sealant to be supplied is determined.

 Next, while the silicone sealant has not been cured, a predetermined amount of a photocatalyst is charged into the adjacent drum 15 and a rotating motion is applied, and the photocatalyst adheres while the pole rolls. The supply amount of silicone sealant is determined by the surface area and film thickness of the ceramic pole.

 (Second embodiment)

 Fig. 3 is a partial cross-sectional view of the pole screw device 20. A screw 22 is supported by bearings 23 and 24 in a u-shaped trough 21 and a motor 26 with a planetary reduction gear is connected via a coupling 25. It is connected to the.

The hopper 19 is fixed to the upper part of the U-shaped trough 21 and has a discharge port 27 near the rear end of the screw 22. First, a ceramic pole with an outer diameter of 6 mm is grounded with primer c (Shin-Etsu Chemical), and the ceramic pole is put into the hopper 21 and given a rotary motion while injecting silicone sealant, the pole rolls. While being applied to a silicone sealant, it adheres uniformly to a film thickness of about 0.1 mm.

 Then, while putting the pole coated with silicone sealant into the hopper of the second pole screw device, the powder of the photocatalyst was dropped, and the pole screw was rotated at about 20 rpm to rotate the pole. It rolled and applied a photocatalyst to the pole surface. The amount of the photocatalyst attached can be determined by the thickness of the silicone sealant.

 (Third embodiment)

 The body of the vibration rolling device is a Sato type vibration screen machine (400 mm diameter) (Koei Sangyo Co., Ltd.). Fig. 4 is a schematic longitudinal sectional view of the vibration rolling device 30. The vibration rolling device 32 (detailed structure is not shown) is mounted on the base 31, and the screen 33 is incorporated in the upper part. A circular pallet 34 is fixed above the hole 33a having the flange portion. The bottom of the circular pallet 34 is inclined toward the center. In addition, a hole 34a is drilled in the center to allow powder and ceramic poles to fall. In the hole 34a, a lid 35b is attached to a rod 35a of an elevating cylinder 35 provided at an upper portion.

 First, a ceramic pole with an outer diameter of 6 mm was treated with primer C (Shin-Etsu Chemical) undercoating, and the silicone roller was uniformly spread to a thickness of about 0.1 mm with the drum rolling device or the pole screw device. Adhere to.

Next, when a ceramic pole is put on the photocatalyst powder previously placed in the circular pallet 34 and vibration is applied, the pole is rolled and the photocatalyst can be applied to the pole surface. The adhesion amount of the photocatalyst can be determined by the supply amount of the silicone sealant. Approximately 3 minutes later, the lifting cylinder 35 is operated, the lid 35b is opened, and vibration is applied to fully fill the powder and ceramic pole. Drop on 3 3 The screen 33 is provided with a wire mesh and receives the powder and the ceramic pole dropped on the wire mesh, and the ceramic pole drops from the outlet 32 _a to the receiving tray 36. Also, the powder falls down from the wire mesh and is collected in the receiving tray 37 from the outlet 32b.

 (Fourth embodiment)

 As described in Examples 1 to 3, after the silicone binder was formed on the surface of the sphere, the sphere and the photocatalyst powder were charged along a linear or spiral inclined guide surface (not shown), and the weight of the sphere was changed. The photocatalyst powder is attached to the surface of the sphere while rolling.

 As described above, the surface of the photocatalyst of the ceramic pole treated with the photocatalyst film in the first, second, third, and fourth embodiments exudes the silicone oil component from the silicone-based sealant material. Covers the surface of the photocatalyst and does not exhibit its full photocatalytic effect. Therefore, a silicone sealant of an organic silicone is immersed in hot water to forcibly degas organic substances (for example, methylethylketoxime) in the silicone sealant and also exude silicone oil. The organic matter in the water is treated by the photocatalyst powder dispersed in the hot water by photoexcitation of the photocatalyst by ultraviolet light, and the organic matter on the photocatalyst surface is decomposed by the photocatalyst attached to the sphere surface, and the photocatalyst surface fixed to the sphere surface Decomposes organic matter.

 By this treatment, the photocatalyst particles are kept exposed, and at least a part of the organic groups bonded to the silicon atoms is replaced with hydroxyl groups, and the surface is wetted by forming a physically adsorbed water layer thereon. It exhibits a high degree of hydrophilicity at an angle close to 0 degrees and promotes the activation of the photocatalyst, and can exhibit the photocatalyst in sewage treatment.

For reference, Fig. 8 shows a scanning electron micrograph of the surface state of titanium oxide (Tika! ^-600) after these treatments. Photocatalyst after these treatments It can be seen that the surface condition is extremely good.

 In this specification, “titanium oxide” is used as an example of a photocatalyst. However, in the present invention, not only ordinary photocatalysts but also all photocatalyst powders such as visible light responsive photocatalysts, apatites, and coated photocatalysts are used. It is targeted.

 As the ultraviolet lamp for irradiating the photocatalyst layer, a germicidal lamp, a low-pressure mercury lamp, an excimer lamp, or the like, which is preferably high in intensity and high in radiation efficiency, is used. Further, instead of the ultraviolet lamp, the ozone water may be supplied by an ozone generator to act on the photocatalyst surface.

 (Test Example 1)

The material of the sphere is selected from inorganic materials such as ceramics, unglazed porcelain clay, glass and the like. Here, a ceramic pole is used. Ceramics mechanical strength as well thermal expansion coefficient is small stable mullite _{(3A 1 2 0 3 - 2Si0} 2) using, as the silicone binder, a silicone sheet one La cement "sealant 4 5" (manufactured by Shin-Etsu Chemical Co., ) It was used. The base of the sphere was pre-treated with Primer C (Shin-Etsu Chemical).

 Regarding the photocatalyst-coated ceramic poles manufactured by the tumbling method, the methylene blue reaction was regarded as a change in methylene blue absorbance and the methylene blue reaction was regarded as a change in methylene blue absorbance, and the absorbance change with the temperature of the methylene blue solution was observed.

Fig. 5 is a diagram showing the time change of the absorbance of methylene blue, with the vertical axis representing the absorbance and the horizontal axis representing the time, showing the change in the absorbance. The reaction conditions for the decolorization of the methylene blue reaction were as follows: methylene blue concentration: 0.05 mmO1, methylene blue solution: 30 cc, sample: 92 spheres, 92 particles, irradiation light: black light (center wavelength: 365 nm) The intensity was about 1 mW / cm ² ), the solution temperature was 40 ° C., and the reaction time was 10 minutes, 20 minutes, and 30 minutes. Fig. 4 shows the results. As can be seen from the figure, the absorbance drops sharply to 0.10 at 10 minutes, and becomes almost 0 at 30 minutes thereafter. I got it.

 (Test Example 2)

The material of the sphere is selected from inorganic materials such as ceramics, unglazed porcelain clay, glass and the like. Here, a ceramic pole is used. Ceramics mechanical strength as well thermal expansion coefficient is small stable mullite _{(3A 1 2 0 3 - 2Si0} 2) using, as the silicone binder, a silicone sealer cement "shea one runt 4 5" (manufactured by Shin-Etsu Chemical Co., ) It was used. The base of the sphere was pre-treated with Primer C (Shin-Etsu Chemical).

 A sample was prepared in the same manner as in Test Example 1 above using a mixed powder in which titanium oxide and iron oxide were mixed at a weight ratio of 1: 1 and an absorbance test was performed.

 Solution temperature: 40 ° (:, reaction time: 10 minutes, 20 minutes, 30 minutes. As a result, the results shown in Fig. 6 were obtained. As can be seen from the figure, the absorbance was 10 minutes. The temperature rapidly dropped to 0.10, and became almost 0 in 30 minutes thereafter.To observe the effect on temperature, the test was performed under the same test conditions and at a temperature of 20 ° C. As a result, it was found that the reaction time was slightly slower at 20 ° C than at 40 ° C.This was because the photocatalyst of the mixture of titanium oxide and iron oxide had a higher temperature. Is affected by

 (Test Example 3)

The material of the sphere is selected from inorganic materials such as ceramics, unglazed porcelain clay, glass and the like. Here, a ceramic pole is used. Ceramics mechanical strength as well thermal expansion coefficient is small stable mullite _{(3A 1 2 0 3 - 2Si0} 2) using, as the silicone binder, a silicone sealer cement "sealant 4 5" a (Shin-Etsu Chemical Co.) used. The base of the sphere was pre-treated with Primer C (Shin-Etsu Chemical).

A sample was prepared in the same manner as in Test Example 1 using a mixed powder in which titanium oxide and iron oxide were mixed in a one-to-one ratio, and a methylene blue absorbance test was performed. The solution temperature was 40 ° C, the reaction time was 10 minutes, 20 minutes, and 30 minutes, and the effects of irradiation with and without black light were tested. As a result, the result shown in FIG. 7 was obtained. As can be seen from the figure, when irradiated with black light, the absorbance dropped sharply to 0.10 at 10 minutes, and became almost 0 at 30 minutes thereafter. On the other hand, it can be seen that the reaction of the absorbance is slightly delayed when no black light is irradiated.

 This is thought to be because the reaction of the mixed powder photocatalyst of titanium oxide and iron oxide depends on the presence or absence of ultraviolet rays.

 (Test Example 4)

 The material of the sphere is selected from inorganic materials such as ceramics, unglazed pottery, glass peas, and the like. Here, a ceramic pole is used. Ceramics are stable mullite with low thermal expansion coefficient as well as mechanical strength

_{(3A 1 2 0 3 - 2Si0} 2) using, as the silicone binder were used silicone sheet one runt "shea one runt 4 5" a (Shin-Etsu Chemical Co.). The base of the sphere was pretreated with Primer C (Shin-Etsu Chemical).

A sample was prepared in the same manner as in Test Example 1 above using a mixed powder in which bamboo charcoal and titanium oxide were mixed at a volume ratio of 1: 1 and a methylene blue absorbance test was performed. The solution temperature was 40, the reaction time was 10 minutes, 20 minutes, and 30 minutes, and the effects of irradiation with and without black light were tested. As a result, the result shown in FIG. 9 was obtained. As can be seen from the figure, when irradiated with black light, the absorbance dropped sharply to 0.10 at 10 minutes, and then became nearly zero at 30 minutes thereafter. On the other hand, it can be seen that the reaction of the absorbance is slowed down without irradiation with black light. This is thought to be due to the difference in the reaction of the photocatalyst attached to the bamboo charcoal due to ultraviolet rays. It is not clear how organic matter adsorbed on bamboo charcoal is decomposed. Figure 10 shows a photo of an adsorption-decomposition type photocatalyst in which titanium oxide is coated on bamboo charcoal. The ground is bamboo charcoal, and shows that titanium oxide is attached to it. Since the methylene blue absorbance test also included adsorbed berries, the adsorption amount was determined by the gas pack method specified by the Photocatalyst Council. The results are shown in Table 1. table 1

(Test Example 5)

 In some cases, silicone oil components may ooze out of the silicone sealant material or the photocatalytic effect may not be sufficiently exerted. The time can be reduced slightly. The modified silicone-based sealant is, for example, a one-component or two-component type modified by various modifiers such as epoxy-modified, alkyd-modified, polyether-modified, acrylic-modified, and `` amino-modified. '' It contains various modified silicone sealants and polysulfide-based sealants (one-component and two-component).

Since low-molecular siloxysan (cyclic trimer and 20-mer) is volatilized and covers titanium oxide, pure sealants such as deoxime-type or deaceton-type have been developed. By using these, the decomposition time of organic substances can be reduced. Here, the same tests as in Test Examples 1 to 4 were conducted using a modified silicone-based sealant “Hamalite Super !!” manufactured by Yokohama Rubber Co., Ltd. as a modified silicone-based or polyisobutylene-based sealant. The result As a result, similar test results were obtained.

 It is also possible to improve the catalytic effect by selecting any one of platinum, copper, and aluminum powders for the photocatalyst spheres produced by the method of rolling the photocatalyst spheres and mixing with the porous body. it can.

 As described in the above embodiments, the rolling molding method of the photocatalyst and the like of the present embodiment does not require complicated scientific processing such as the conventional sol and gel methods, and can be used in a pan-type rolling method compared to the manufacturing method. It can be mass-produced in a short time because it is manufactured by mechanical processing using a rolling device using a device or planetary motion, a pole screw rolling device, and a vibrating rolling device. As a result, the sphere can be coated with the photocatalyst at a high density, so that the photocatalyst can exhibit high organic substance decomposition ability, capture harmful organic substances by suction, decompose organic substances such as bacteria, and eliminate pollution. . Furthermore, a silicone sealant of an organic silicone is immersed in hot water to forcibly degas organic substances (eg, methyl ethyl ketoxime) in the silicone sealant, exude silicone oil, and further emit ultraviolet light. The organic matter in the water is treated by the photocatalyst powder dispersed in the hot water by the photoexcitation of the photocatalyst, and the organic matter on the photocatalyst surface is decomposed by the photocatalyst attached to the sphere surface, and the organic matter on the photocatalyst surface fixed to the sphere surface Is decomposed.

In addition, in the process of imparting hydrophilicity in hot water, the organic substances mixed in the silicone binder are dispersed in water without vaporizing, and are decomposed by ultraviolet irradiation using the curing of the photocatalyst, harming the work environment. It can be produced without any problems.

Although some examples were shown in the test examples, mixed powders of titanium dioxide and iron oxide and mixed powders of titanium dioxide, iron oxide and carbide were also used for porous materials such as charcoal, bamboo charcoal, and activated carbon. Organic matter is collected at night without light by a photocatalyst consisting of powder selected from the body, and the organic matter is efficiently decomposed by daylight sunlight Can be. Industrial applicability

 According to the present invention, using a pan-type rolling device or a rolling device utilizing planetary motion, a pole screw rolling device, or a vibrating rolling device, a silicone binder is formed on a surface of a sphere by a film forming means to a predetermined film thickness. A photocatalyst is applied by a coating means while the silicone binder is not cured, and a silicone sealant of organic silicone is immersed in hot water to forcibly form the inside of the silicone sealant. Degass organic matter (eg, methylethylketoxime) and also exudes silicone oil. Photoexcitation of the photocatalyst by ultraviolet light causes the photocatalyst powder dispersed in the hot water to treat the organic matter in the water and to form a spherical surface. The organic matter on the photocatalyst surface is decomposed by the photocatalyst attached to the surface, and the organic matter on the photocatalyst surface fixed to the sphere surface is decomposed. The product can be decomposed by UV irradiation, utilizing the curing of the photocatalyst, and can be produced without pollution.

Therefore, since the surface of the photocatalyst of the ceramic pole on which the photocatalyst has been formed is water-resistant and can form a hydrophilic layer, it is most suitable as a photocatalyst for water treatment.

Claims

The scope of the claims  1. A film of a silicone binder is formed on the surface of the sphere to a predetermined thickness by a film forming means, and then, while the silicone binder is not yet cured, a photocatalyst is attached by a coating means, and then the excess photocatalyst is washed in water while washing. A method for forming a photocatalyst sphere, comprising decomposing an organic substance emitted from a binder by photoexcitation of a photocatalyst by ultraviolet rays, and forming a hydrophilic layer on the photocatalyst surface in water.  2. The rolling of the photocatalytic sphere according to claim 1, wherein a rolling device that rolls a drum is used as a film forming means, and the silicone binder is formed on the surface of the sphere by rotating the drum. Molding method.  3. The photocatalytic sphere according to claim 1, wherein the sphere is rolled by rotating a pole screw by using a pole screw device as a film forming means, and a silicone binder is formed on the surface of the sphere. Roll forming method. 4. A rolling device that rolls a drum is used as a coating means as a coating means, and a photocatalyst is applied to the surface of the sphere by rotating a sphere and a powder on which a silicone binder is formed in the drum. The method of rolling molding a photocatalyst according to claim 1.  5. The method of rolling molding a photocatalyst according to claim 1, wherein a vibrating device for vibrating a circular pallet is used as a coating means, and the photocatalyst and the pole are adhered while rolling in the circular palette.  6. After the silicone binder is formed on the surface of the sphere, the sphere and the photocatalyst powder are put along the linear or spiral inclined guide surface, and the photocatalyst powder is applied to the sphere surface while rolling by its own weight. 2. The method of rolling molding a photocatalyst according to claim 1, wherein a body is adhered. 7. The method of rolling molding photocatalytic spheres according to claim 1, wherein the silicone binder is a silicone sealant. 7. The method of rolling molding a photocatalyst according to claim 1, wherein the silicone binder is a modified silicone-based or polyisobutylene-based sealant.  9. The method of rolling molding a photocatalyst according to claim 1, wherein the material of the sphere is an inorganic material such as ceramics, unglazed clay, glass beads, and the like.  10. The method according to claim 1, wherein the photocatalyst is titanium dioxide, or a mixed powder of titanium dioxide and a porous powder.  11. The method of claim 1, wherein the porous powder is silica, charcoal, bamboo charcoal, or activated carbon.  12. A photocatalyst sphere produced by the method for rolling a photocatalyst according to claim 1 to claim 11.