JP2007090313A - Inexpensive high active photocatalyst excellent in photolysis of ethylene and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photocatalyst having a high photocatalytic activity capable of efficiently decomposing ethylene which is known as a substance giving a significant influence for retaining freshness of agricultural products such as vegetables and fruits and cut flowers even at an indoor with poor sunlight at a low cost. <P>SOLUTION: The high active photocatalyst excellent in photolysis of ethylene is characterized in that a titanium dioxide composite body produced by impregnating/sintering anatase type particulate titanium dioxide and anatase type titanium dioxide having a particle diameter of 50 nm or more with ammonium sulfate is sintered to integrate it. The high active photocatalyst is manufactured by impregnating the anatase type titanium dioxide having different particle diameters with ammonium sulfate, drying and sintering it and sintering the obtained solid substance at 300-700°C to integrate it. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an inexpensive highly active photocatalyst adapted to light with poor ultraviolet rays such as a white fluorescent lamp and a method for producing the same, and is particularly known as an aging hormone of plants such as agricultural products and cut flowers, and has an important effect on maintaining the freshness thereof. The present invention relates to an inexpensive highly active photocatalyst exhibiting high photolytic activity with respect to ethylene and a method for producing the same.
The present invention relates to a photocatalyst adapted to light with poor ultraviolet rays such as a white fluorescent lamp, and has been strongly desired to be realized in the past. Even if the term is the same photocatalyst, the conventional photocatalyst is effective for the first time under an environment rich in ultraviolet rays, for example, under the irradiation of an ultraviolet radiation lamp or under the direct sunlight outdoors.
Therefore, the present invention responds to light with poor ultraviolet rays such as fluorescent lamps and exhibits sufficient efficacy even under white fluorescent lamps indoors or in cars, so it differs from conventional photocatalysts in both technical and application. It is a field invention.

  Titanium dioxide has a photocatalytic action, and is known as a clean and environmentally-friendly future-oriented substance that can use solar energy to decompose organic substances, for example. Therefore, titanium dioxide has been actively developed in order to put its photocatalytic action into practical use in fields such as air purification and water purification, and has also gained brilliant research results in areas such as pollution prevention of building exterior tiles. Yes. However, these results are mainly in the outdoor field where sunlight including ultraviolet rays can be used, and the research results that are expected to be put to practical use indoors where sunlight is blocked have not been completed. In addition, titanium dioxide for highly active photocatalysts has a very small particle size, which makes the production cost expensive and impedes practical use.

  In order to use the photocatalytic action of titanium dioxide indoors where sunlight does not shine, it is necessary to activate the photocatalytic action of titanium dioxide at a wavelength such as a white fluorescent lamp with poor ultraviolet light. Numerous proposals have already been made regarding highly active photocatalysts of titanium dioxide. Specifically, for example, anatase-type titanium dioxide having excellent photocatalytic action in titanium dioxide is formed on a substrate by chemical vapor deposition and baked at 500 to 900 ° C. to increase the anatase-type crystallinity. A method for improving the photocatalytic action (see Patent Document 1), a method in which titanium alkoxide is applied to a porous ceramic and fired to form a microporous film to enhance photoactivity (see Patent Document 2), and a crystal structure of titanium dioxide Is made conical (see Patent Document 3), a method in which the crystal structure of titanium dioxide is a columnar structure (see Patent Document 4), or the columnar crystal structure of titanium dioxide is hollowed out to increase the contact area and activate. Proposed is a method (see Patent Document 5), a method of increasing the photocatalytic activity by forming and laminating a titanium dioxide film on a substrate by sputtering (see Patent Document 6), and the like. And it has the crystal structure of Besides titanium dioxide, study of various highly active photocatalyst respect crystallinity and crystal structure have been made. However, the evaluation of the photocatalytic activity in these conventionally studied technologies was carried out using a xenon lamp, germicidal lamp or black light, which is rich in ultraviolet rays similar to sunlight, targeting a chemical substance such as acetaldehyde. It is not intended to be a highly activated photocatalyst for indoors where UV rays are scarce.

As another means for increasing the photocatalytic activity of titanium dioxide, a series of proposals using a noble metal together with titanium dioxide has been made. Specifically, platinum, palladium, gold, etc. are supported on the surface of titanium dioxide columnar crystals to increase the photocatalytic activity (see Patent Document 7), and platinum, etc. are supported on rutile titanium oxide in the form of fine particles. For example, a method for improving the activity (see Patent Document 8) and a method for increasing the activity by adding yttrium to titanium oxide (see Patent Document 9) have been proposed. Further, as a special method, a method of obtaining a highly active photocatalyst by supporting a noble metal such as iridium on barium titanate (see Patent Document 10), basic ammonium ammonium sulfate, (NH ₄ ) ₂ SO ₄ · TiOSO ₄・ Sintered 2H ₂ O, synthesized anatase-type titanium dioxide, mixed with titanium metal powder, and fired at 300 to 700 ° C while spraying a small amount of titanium sulfate. A method for obtaining a photocatalyst that can be used (see Patent Document 11) has been proposed. These proposals are often evaluated by evaluating the decomposability of compounds such as acetaldehyde, or using mercury-rich lamps that are rich in ultraviolet rays as the light source, or using sunlight directly as the light source. It is not intended for indoor use of photocatalysts.

  When a platinum catalyst is supported on the rutile type titanium dioxide described in Patent Document 8, the rutile type titanium dioxide is excited by light up to a wavelength of 407 nm (band gap 3.05 eV), and anatase type titanium dioxide. The wavelength of photoexcitation from 388 nm (bandgap 3.20 eV) is on the visible light side (long wavelength), the activation effect of platinum particles is added, the activity is exhibited even in a white fluorescent lamp, and acetaldehyde is decomposed. It is stated in. However, noble metals such as platinum are remarkably expensive as compared with titanium oxide, and practical limitations cannot be avoided in terms of cost.

  For photocatalysts that respond to visible light that does not contain ultraviolet light, titanium oxide is doped with nitrogen (N) or sulfur (S) to form a photocatalytic structure of Ti—O—N or Ti—O—S structure on the substrate. (See Patent Document 12) has been proposed, but the production cost must be increased in consideration of the production rate of the photocatalyst film. As a photocatalyst that can respond to visible light and reduce costs, titanium oxide powder and urea are stirred and mixed, and then heated to produce titanium oxynitride (see Reference 13). As described in the examples, firing in a nitrogen or ammonia atmosphere is necessary, and the photocatalyst production method of this patent is more complicated than the simple firing in air, which is disadvantageous in terms of production cost. Seem.

  Furthermore, many of the previous proposals related to the photodecomposition of ethylene are from the aspect of equipment related to the decomposition and removal of ethylene for the purpose of maintaining the quality of agricultural products, and light is irradiated to titanium dioxide or platinum-supported titanium dioxide to decompose ethylene. One example is a proposal of an apparatus system that maintains the freshness of agricultural products (for example, see Patent Document 14). Proposals related to photolysis of ethylene related to titanium dioxide include an ethylene decomposition catalyst (see Patent Document 15) having excellent water resistance and high photocatalytic activity, in which titanium oxide is supported on zeolite from which alkali metals such as sodium have been removed. An ethylene decomposition catalyst characterized in that a charge separation layer having a good light transmission property is provided on a carrier, and titanium oxide fine particles having a crystal particle diameter of 10 to 50 nanometers are supported thereon (see Patent Document 16) Etc. have been proposed. However, the evaluation method of ethylene degradation found in these patents was made using an ultraviolet germicidal lamp, etc., and its activity is not yet satisfactory as an effective photocatalyst that can be applied indoors where ultraviolet rays are scarce. Absent.

  JP 2000-266902 A (pages 1 to 5)   JP 2001-259435 A (pages 1 to 6)   JP 2002-253974 A (pages 1 to 8)   JP 2002-370034 A (pages 1-7)   JP 2003-190810 A (pages 1 to 15)   JP-A-11-47609 (pages 1 to 8)   JP 2003-299965 A (pages 1 to 12)   JP 2000-262906 A (pages 1 to 11)   JP 11-244706 A (pages 1 to 4)   JP-A-9-253486 (pages 1-7)   JP-A-7-275702 (pages 1 to 5)   JP 2001-207082 A (pages 1 to 9)   JP 2002-154823 A (pages 1 to 7)   JP-A-1-252244 (pages 1 to 11)   JP 7-16473 A (pages 1 to 6)   JP-A-7-88367 (pages 1-6)   Satoshi Ozaki et al. “Catalyst Preparation Chemistry”, p. 49, Kodansha Scientific (1980)   52nd page of "9th Catalysis School Text" sponsored by the Catalysis Society of Japan, Catalysis Society of Japan (1998)

  The present invention is known to have a significant effect on maintaining the freshness of agricultural products such as vegetables and fruits and cut flowers, not only under sunlight, but also indoors where sunlight is poor, such as under the irradiation of a white fluorescent lamp. An object of the present invention is to provide a general-purpose and inexpensive photocatalyst having high photocatalytic activity capable of efficiently decomposing ethylene. Furthermore, it is intended to provide an inexpensive general-purpose photocatalyst that can be uniformly mixed when mixed into paint, etc., and exhibits high photocatalytic activity even under the light of a white fluorescent lamp that is used indoors for ordinary lighting. is there.

  In view of the above situation, the present inventor has conducted extensive research on a general-purpose photocatalyst using titanium dioxide that photodecomposes ethylene even in sunlight-poor indoors. A titanium dioxide composite was found and the present invention was completed.

That is, the gist of the present invention is as follows.
(1) A highly active photocatalyst excellent in photolysis of ethylene, wherein a titanium dioxide composite produced from two or more types of titanium dioxide and ammonium sulfate having different particle diameters is baked and integrated.
(2) The highly active photocatalyst according to (1), wherein the titanium dioxide has an anatase type crystal structure.
(3) The highly active photocatalyst according to (1) and (2), wherein the particle size of titanium dioxide having a small particle size is less than 8 nm, and the particle size of titanium dioxide having a larger particle size is 50 nm or more.
(4) The highly active photocatalyst according to any one of (1) to (3), wherein the titanium dioxide composite is obtained by impregnating titanium dioxide with ammonium sulfate.
(5) The high activity photocatalyst according to (1) to (4), wherein the impregnation amount of ammonium sulfate with respect to titanium dioxide is 1 to 20 mol% in any composite of any particle size. The high-activity photocatalyst according to (1) to (5), wherein the weight ratio of the composite of titanium and the titanium dioxide composite having a large particle size is 5/95 to 40/60. The method for producing a highly active photocatalyst according to any one of (1) to (6), wherein a titanium dioxide composite produced from titanium dioxide and ammonium sulfate is baked and integrated.
(8) The highly active photocatalyst according to (7), wherein two or more types of titanium dioxide having different particle diameters are calcined and integrated, and then a titanium dioxide composite formed by impregnation with ammonium sulfate is calcined. Production method.
(9) The method for producing a highly active photocatalyst according to (7), wherein the titanium dioxide composite formed by impregnating ammonium sulfate into each of two or more types of titanium dioxide having different particle diameters is fired and integrated. .

  A highly active photocatalyst excellent in photodecomposition of ethylene, characterized by firing and integrating a titanium dioxide composite produced from two or more types of titanium dioxide and ammonium sulfate having different particle diameters, is manufactured at low cost. It is a photocatalyst that has high activity for ethylene decomposition even with light that is as low in ultraviolet rays as white fluorescent lamps for indoor lighting. Therefore, if the photocatalyst of the present invention is used, it is not necessary to irradiate sunlight rays or ultraviolet lamp light including ultraviolet rays, and vegetables and fruits are stored indoors, in cars, outdoors where sunlight is blocked. Even if it exists, the generated ethylene can be decomposed efficiently.

The titanium dioxide composite which is a highly active photocatalyst of the present invention is obtained by firing and integrating a titanium dioxide composite produced from two or more types of titanium dioxide and ammonium sulfate having different particle sizes. Specifically, it is a composite obtained by mixing titanium dioxide having a particle size of less than 8 nm and titanium dioxide having a particle size of 50 nm or more, impregnating the mixture with ammonium sulfate, and then firing the mixture. Alternatively, a composite obtained by impregnating and sintering ammonium sulfate in titanium dioxide having a particle diameter of less than 8 nm and a composite obtained by impregnating and sintering ammonium sulfate in titanium dioxide having a particle diameter of 50 nm or more are mixed and further baked It is. In any composite of any particle size, the component element constituting ammonium sulfate is a titanium dioxide composite that is integrally combined on the surface or inside of the titanium dioxide particles.
Although the structure and mechanism of the highly active photocatalyst of the present invention using such a titanium dioxide composite is not necessarily clear, a typical composite of the present invention is a titanium dioxide composite impregnated with 8 mol% of ammonium sulfate. The ultraviolet / visible absorption spectrum (see FIG. 1) shows almost no absorption around 400 nm, and a spectrum similar to that of general titanium dioxide can be obtained. Unlike the increase in the absorption spectrum near 400 nm, which is different from the above, it seems that the photocatalytic activity is increased in the ultraviolet light or visible light region close to the visible region by another action. One possibility is that electrons and holes generated by receiving light are less likely to recombine, resulting in an increase in photocatalytic activity efficiency. Therefore, it is considered to be a novel highly active photocatalyst having properties different from those of Patent Document 12 even in an environment where ultraviolet rays are scarce.

As the raw material titanium dioxide (TiO ₂ ) used in the present invention, any of anatase type, rutile type or brookite type crystal type or amorphous type can be used, but anatase type titanium dioxide is preferred. Those having a small particle size are less than 8 nm (8 × 10 ⁻⁹ m), and those having a large particle size are about 50 nm (50 × 10 ⁻⁹ m) to 1 μm (10 ⁻⁶ m). You can use anything. More preferably, the small particle size is 3 nm (3 × 10 ⁻⁹ m) to 7 nm (7 × 10 ⁻⁹ m). If it is less than 3 nm, the manufacturing cost is very high, and it is too fine to work. The preferred range for large particle sizes is from 100 nm (100 × 10 ⁻⁹ m) to 500 nm (500 × 10 ⁻⁹ m). If it is less than 100 nm, the price is not cheap and the features of this patent cannot be utilized. Moreover, when it is 500 nm or more, the particle size is too large, and when mixed with the coating film, the smoothness of the coating film becomes poor, and when kneaded into a film, it is difficult to knead uniformly. In this patent, the particle diameter means the diameter of primary particles. The titanium dioxide used in the present invention can be used as a raw material as it is marketed as a product. However, if desired, hydrolysis of titanium salts such as titanium salts of inorganic acids such as titanium sulfate, titanium tetrachloride and titanium nitrate, or titanium tetraethoxide, titanium tetraisopropoxide or titanium tetra (2-ethylhexanoate) Or it can also prepare by methods, such as neutralization, precipitation, and baking, with basic substances, such as caustic soda. Of the above, anatase-type titanium dioxide is sold as a photocatalyst that can be used in a conventional ultraviolet-rich environment.

In the highly active photocatalyst of the present invention in which titanium dioxide composites having different particle sizes are integrated, the weight ratio of the titanium dioxide composite having a small particle size and the titanium dioxide composite having a large particle size is 5/95 to 40. / 60 is preferable. If the weight ratio of the titanium dioxide composite having a small particle diameter is less than 5%, the photocatalytic activity is insufficient, and if it is 40% by weight or more, the cost increases, which is not preferable. A more preferable range for achieving both high activity and low cost is a weight ratio of 8/92 to 30/70.

Representative products of commercially available anatase titanium dioxide include AMT-100, AMT-600, JA-1, manufactured by Teika Co., Ltd., SSP-25, A-110, CSPM, CSB manufactured by Sakai Chemical Industry Co., Ltd. ST-01 and ST-41 manufactured by Ishihara Sangyo Co., Ltd. are known, and it is possible to prepare a titanium dioxide composite using these titanium dioxides.
Note that the price of titanium dioxide tends to increase as the particle size decreases. In particular, in anatase type titanium dioxide having a particle size of less than 8 nm, the photocatalytic activity is high but very expensive. In contrast, the activity of a slightly larger particle having a particle size of 50 nm or more decreases in photocatalytic activity as the particle size increases, but it can be obtained at a low cost, and the activity of 100 nm or more can be obtained at a lower cost.
The present inventor baked and integrated the anatase-type titanium dioxide having a fine particle size of less than 8 nm, the anatase-type titanium dioxide of 50 nm or more and ammonium sulfate, thereby integrating the fine particle size of less than 8 nm. The present invention was completed by finding a sufficiently large photocatalytic activity even with a small amount of anatase-type titanium dioxide used, that is, photocatalytic activity in irradiation of a white fluorescent lamp with poor ultraviolet rays.

  Ammonium sulfate used in the present invention can be used as a reagent or for industrial use, and its purity is not specified. Ammonium sulfate is industrially mass-produced as a fertilizer, etc., inexpensive and stable quality is readily available, and its solubility in water is large, so that the impregnation operation is easy, and there is no problem with regard to safety. When used as a very good.

Next, a method for producing a photocatalyst exhibiting high activity even in an inexpensive and white environment such as a white fluorescent lamp according to the present invention will be described.
One is a method in which two or more types of titanium dioxide having different particle diameters are baked and integrated, and then a titanium dioxide composite formed by impregnation with ammonium sulfate is baked. That is, anatase type fine particle titanium dioxide and anatase type titanium dioxide having a larger particle size are uniformly mixed, dried and fired to be integrated, then impregnated with ammonium sulfate, dried and fired, and integrated anatase type titanium dioxide composite A way to get a body.
The other is that two or more types of anatase-type titanium dioxide having different particle diameters are impregnated with ammonium sulfate, dried and fired, and then anatase-type titanium dioxide composites having different particle diameters are uniformly mixed at a predetermined ratio. It is a method of firing and integrating.

  Furthermore, the manufacturing method of the titanium dioxide composite which is the highly active photocatalyst of this invention is demonstrated. The method for preparing the titanium dioxide composite of the present invention is usually applied to a composite of a small particle size and a large particle size, a composite of a small particle size, and a composite of a large particle size. Uses an impregnation method (see Non-Patent Documents 1 and 2). That is, titanium dioxide and an aqueous ammonium sulfate solution are mixed well to make uniform, impregnating or adsorbing ammonium sulfate on titanium dioxide, dried and fired at a temperature of about 20 to 100 ° C., and then pulverized to include a titanium dioxide composite containing ammonium sulfate. May be prepared.

  A coprecipitation method (see Non-Patent Documents 1 and 2) can be used to prepare a titanium dioxide composite having a small particle size and a large particle size. In the case of coprecipitation, a commercially available aqueous solution of titanium sulfate and an aqueous solution of ammonium sulfate are mixed and neutralized with an aqueous sodium hydroxide solution or aqueous ammonia to produce titanium dioxide containing ammonium sulfate by coprecipitation, followed by filtration and washing. The powder obtained as described above may be dried and fired at a temperature of about 20 to 100 ° C. and then pulverized to prepare titanium dioxide containing ammonium sulfate.

  The amount of ammonium sulfate contained in the titanium dioxide is usually from 1 to the composite of a composite having a small particle size and a large particle size, a composite having a small particle size, and a composite having a large particle size. Although it is about 20 mol%, it is preferably about 2 to 15 mol%. If it is 1 mol% or less, the activity is small, and if it is 20 mol% or more, the photocatalytic activity tends to decrease. Therefore, it is usually preferable to limit the amount to 20 mol% or less. However, it does not preclude the use of an amount of 20 mol% or more if specifically desired. Moreover, as titanium dioxide containing ammonium sulfate used in the present invention, in addition to those obtained by impregnation, adsorption and coprecipitation as described above, titanium dioxide containing ammonium sulfate is further washed, heated and dried, and calcined. In addition, those in which chemical structural changes are caused by thermal decomposition in various processes such as pulverization are also included.

    The highly active photocatalyst using the titanium dioxide composite of the present invention as described above decomposes ethylene generated during storage of agricultural products, cut flowers, etc., and is therefore extremely useful for maintaining the quality of these. The high activity catalyst may be used as it is, but can be used in various forms such as being mixed with a paint or supported on a plastic film. In addition to photocatalytic activity in response to the light of white fluorescent lamps, in addition to the decomposition of ethylene, conventional decomposition of organic substances such as aldehydes, removal of malodors, purification of car exhaust gas, antibacterial properties, etc. The effect of the photocatalyst can be exhibited even in an environment with poor ultraviolet rays, such as indoors or in a car.

Next, prior to describing examples of the present invention, an evaluation method when the photocatalyst decomposes ethylene by irradiation with a white fluorescent lamp will be described.
(I) Structure of apparatus Although there is no special restriction for the apparatus used for evaluation, it is usually composed of the following four kinds of apparatuses. (1) Glass petri dish (inner diameter 66 mm): A 0.1 g sample is mixed with water and uniformly applied and dried to prepare a thin film. (2) Quartz cell (cylindrical, internal volume 300 ml): The petri dish coated with the sample is stored, the inside is replaced with oxygen / argon = 20% / 80% synthesis gas, and 5 ppm of ethylene is inserted. Excellent quartz airtight container. (3) Irradiation box (W × L × H = 75 × 70 × 75 cm): A container in which a quartz cell is housed and light is irradiated with a white fluorescent lamp. Circulate air and adjust temperature. (4) Gas chromatograph: analyzer for ethylene and the like.

(Ii) Operating procedure A sample and water are added and uniformly applied to a glass petri dish (inner diameter 66 mm), dried, and the petri dish is placed in an airtight cylindrical quartz cell. Next, the gas in the cell is sufficiently replaced with argon gas (synthetic air) containing 20% oxygen. The cell is placed in an irradiation box with a white fluorescent lamp. The sample in the quartz cell stored in the irradiation box is irradiated with light according to the schedule for ethylene decomposition evaluation shown below, and the concentration change due to ethylene decomposition during the period is measured by gas chromatograph to measure the photolysis activity of the sample. To evaluate.

(Iii) Evaluation schedule for ethylene photolysis A sample is placed in a petri dish, and the surface of the sample is cleaned by irradiation with black light (20 W, 1 mW / cm ² at a wavelength of 365 nm) for 3 hours in advance. Place in the interior and replace with synthetic air (O ₂ / Ar = 20% / 80%). Insert ethylene gas to a concentration of 5 ppm and leave in the dark for 90 minutes. Next, the cell is placed in an irradiation box, half of a 20 W fluorescent lamp is covered with aluminum foil, and light irradiation (500 Lux) is started. The ethylene concentration after 60, 120, and 180 minutes is measured with a gas chromatograph, Check for photolytic activity.
The reason for leaving it in the dark for 90 minutes is to allow ethylene to be adsorbed on the sample surface until it reaches adsorption equilibrium.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to the Example shown below. In the examples, “%” and “part” are based on mass unless otherwise noted.

1.1 Preparation of an integrated product (1.2) of a small particle size titanium dioxide and a large particle size titanium dioxide White titanium dioxide AMT-100 {(1 -1-1), 1.0 g having a particle size of 6 nm and a specific surface area of 260 m ² / g} was put into a magnetic petri dish, and then white titanium dioxide JA- having an anatase type crystal structure also provided by Teika Co., Ltd. 1 {(1-1-2), particle size 180 nm, specific surface area 9 m ² / g} of 9.0 g was put into a magnetic petri dish, stirred uniformly, fired in a muffle furnace for 3 hours at 600 ° C. and cooled. Then, lightly pulverize, lightly apply the cool air of the dryer, blow off the fine powder of titanium dioxide, and integrate the small particle size titanium dioxide and large particle size titanium dioxide (1.2) It was obtained .7g a (97.0% yield). This integrated titanium dioxide (1-2) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD). The X-ray diffractometer (XRD) used was a fully automatic diffractometer, MXP ³ A, manufactured by Mac Science. In the following Examples and Comparative Examples, the same machine was used for all X-ray diffraction measurements.

1.2 Adjustment of Integrated Titanium Dioxide Composite {TiO ₂ ((NH ₄ ) ₂ SO ₄ ) _0.08 } (1-3) Ammonium sulfate (pure Wako Pure) to 10.0 g of integrated titanium dioxide (1.2) A uniform solution of 1.3 g (10 mmol, 8 mol% with respect to titanium dioxide) of (NH ₄ ) ₂ SO ₄ , MW: 132.14) manufactured by Yaku Kogyo Co., Ltd. and 10 ml of water was mixed well, and ammonium sulfate was added. And then dried at about 80 ° C. for about 2 hours. Next, after calcination at 500 ° C. for 3 hours in a muffle furnace and cooling, 9.5 g of titanium dioxide composite (1-3) pulverized and containing ammonium sulfate [MW: 79.9, ammonium sulfate is not included in the calculation of molecular weight] Yield: 84.1%) was obtained. This titanium dioxide containing ammonium sulfate (1-3) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

1.3 Preparation of petri dish (1-4) with integrated titanium dioxide composite (1-3) and determination of installation position in irradiation box Integrated titanium dioxide composite obtained in 1.2 above ( 1-3) of 0.1 g was put into a glass petri dish having an inner diameter of 66 mm, and 3.0 g of water was added and mixed uniformly, followed by drying for 1 hour in a drier. Thus, the titanium dioxide composite (1-3) having a substantially uniform thickness was applied to the bottom of the petri dish. Next, half of one 20 watt daylight fluorescent lamp (FL20SS · EX-N / 18-Z manufactured by Toshiba Lighting & Technology Co., Ltd.) is covered with aluminum foil to shield it, and the light emitting part is halved to the top of the irradiation box. The position where it was installed and turned on to become 500 Lux was determined. The illuminance was confirmed with a Minolta illuminometer T-10. In the following Examples and Comparative Examples, the 20-watt daylight white fluorescent lamp (FL20SS · EX-N / 18-Z manufactured by Toshiba Lighting & Technology Corp., light emitting unit: 1/2) was used as a light source.

1.4 Preparation of a mixed gas containing 200 ppm of ethylene and preparation of a mixed gas of 5 ppm of ethylene in a quartz cell (1-5) containing a petri dish (1-4) containing an integrated titanium dioxide composite powder sample 1 The gas in the liter glass collection bottle (manufactured by GL Sciences) was replaced with a mixed gas of 80% argon and 20% oxygen for about 10 minutes, and 0.2 ml of ethylene gas was injected through the septum attached to the collection bottle to 200 ppm. A mixed gas was prepared.
The petri dish (1-4) containing the powder sample was placed in a quartz cell, and the gas inside was replaced with a mixed gas of 80% argon and 20% oxygen for 10 minutes. 7.5 ml of a mixed gas containing 200 ppm ethylene was injected through a septum attached to the quartz cell, and the ethylene concentration in the mixed gas in the quartz cell was adjusted to 5 ppm. This completed the preparation of a quartz cell (1-5) in which a mixed gas of 0.1 g of sample powder, 5 ppm of ethylene and 80% of argon and 20% of oxygen was put and sealed with a septum.

1.5 Measurement of ethylene concentration after leaving titanium dioxide composite in dark place Petri dish with integrated titanium dioxide composite (1-4), 5ppm ethylene gas, mixed gas of argon 80% oxygen 20% The quartz cell (1-5) was placed in the dark and the ethylene concentration after 60 minutes and 90 minutes was measured. As shown in Table 1, they were 5.0 ppm and 4.9 ppm, respectively.

1.6 Measurement of Ethylene Concentration when Titanium Dioxide Composite is Irradiated with Daylight White Fluorescent Lamp Next, petri dish with titanium dioxide composite (1-4), 5 ppm ethylene gas, argon 80% oxygen, 20% mixed gas Place the quartz cell (1-5) left in the dark place with a illuminance of 500 Lux in the irradiation box, and use aluminum foil for the central part 1/2 of one 20-watt daylight white fluorescent lamp. What was rolled and shielded and the light emitting part was halved was placed on the irradiation box and turned on, and the ethylene-containing mixed gas in the quartz cell (1-5) was irradiated with daylight white fluorescent light. At this time, the ethylene concentration in the quartz cell (1-5) was extracted with a syringe through a septum after 60 minutes, 120 minutes, and 180 minutes of irradiation with a fluorescent lamp, and a gas chromatograph (GC353B type FID, manufactured by GL Sciences Inc.) was extracted. The ethylene concentration was measured with a gas chromatograph, column: Porapak Q, column temperature 110 ° C. As shown in Table 1, the measurement results were 4.7 ppm, 4.2 ppm, and 3.8 ppm, respectively.

2.1 Preparation of Integration (2-2) of Small Titanium Dioxide and Large Titanium Dioxide (2-2) White Titanium Dioxide AMT-100 {(2 -1-1), 2.0 g having a particle size of 6 nm and a specific surface area of 260 m ² / g} were put into a magnetic petri dish, and then white titanium dioxide JA- having an anatase type crystal structure also provided by Teika Co., Ltd. 1 {(2-1-2), particle size 180 nm, specific surface area 9 m ² / g} 8.0 g was put into a magnetic petri dish, stirred uniformly, fired in a muffle furnace for 3 hours at 600 ° C. and cooled. Then, it lightly grind | pulverized, the cold wind of the dryer was lightly applied, and the fine powder of titanium dioxide was blown off, and 9.6g (yield 96.0%) of the integrated product (2-2) was obtained. This integrated titanium dioxide (2-2) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

2.2 Adjustment of Integrated Titanium Dioxide Composite {TiO ₂ ((NH ₄ ) ₂ SO ₄ ) _0.08 } (2-3) To 10.0 g of integrated titanium dioxide (2-2), ammonium sulfate (Wako Pure) A uniform solution of 1.3 g (10 mmol, 8 mol% with respect to titanium dioxide) of (NH ₄ ) ₂ SO ₄ , MW: 132.14) manufactured by Yaku Kogyo Co., Ltd. and 10 ml of water was mixed well, and ammonium sulfate was added. And then dried at about 80 ° C. for about 2 hours. Next, after calcination at 500 ° C. for 3 hours in a muffle furnace, cooling, and lightly pulverizing, 9.7 g of an integrated titanium dioxide composite (2-3) [MW: 79.9, ammonium sulfate is not included in the calculation of molecular weight] (Yield 85.8%) was obtained. This integrated titanium dioxide (2-3) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

2.3 Preparation of Petri dish (2-4) with Integrated Titanium Dioxide Composite (2-3) and Determination of Installation Position in Irradiation Box The same procedure as in Example 1 was performed.

2.4 Preparation of mixed gas containing 200 ppm of ethylene and preparation of mixed gas of 5 ppm of ethylene in quartz cell (2-5) containing petri dish (2-4) with integrated titanium dioxide composite powder sample Performed as in Example 1.

2.5 Measurement of the ethylene concentration after leaving the titanium dioxide composite in the dark An integrated petri dish with titanium dioxide composite (2-4), 5 ppm ethylene gas, 80% argon, 20% oxygen mixed gas entered When the quartz cell (2-5) was placed in a dark place and the ethylene concentration after 60 minutes and 90 minutes passed was measured, it was 5.0 ppm and 5.0 ppm, respectively, as shown in Table 1.

2.6 Measurement of Ethylene Concentration when Titanium Dioxide Composite is Irradiated with White White Fluorescent Lamp Next, Petri dish with titanium dioxide composite (2-4), mixed gas of 5 ppm ethylene gas, argon 80% oxygen 20% Place the quartz cell (2-5) left in the dark place with the illuminance of 500 Lux in the irradiation box, and use aluminum foil for the central part 1/2 of one 20-watt daylight white fluorescent lamp. What was rolled and shielded and the light emitting part was halved was placed on the irradiation box and turned on, and the ethylene-containing mixed gas in the quartz cell (2-5) was irradiated with daylight white fluorescent light. At this time, the ethylene concentration in the quartz cell (2-5) was extracted with a syringe through a septum after 60 minutes, 120 minutes, and 180 minutes of irradiation with a fluorescent lamp, and a gas chromatograph (manufactured by GL Sciences, GC353B type FID). The ethylene concentration was measured with a gas chromatograph, column: Porapak Q, column temperature 110 ° C. As shown in Table 1, the measurement results were 4.5 ppm, 3.8 ppm, and 3.1 ppm, respectively.

3.1 Integration of small particle size titanium dioxide and large particle size titanium dioxide.
The integrated titanium dioxide (2-2) prepared in Example 2 was used.

3.2 Integrated titanium dioxide composite {TiO ₂ ((NH ₄ ) ₂ SO ₄ ) ₀ . ₁₂ } Adjustment of (3-3) 10.0 g of the integrated titanium dioxide (2-2) shown in 3.1 was placed in a magnetic petri dish, and then ammonium sulfate (Wako Pure Chemical Industries, Ltd., (NH ₄ ) ₂ SO ₄ , MW: 132.14) 2.0 g (15 mmol, 12 mol% with respect to titanium dioxide) and 10 ml of water were added in a homogeneous solution, mixed well, impregnated with ammonium sulfate, and then about 80 ° C. And dried for about 2 hours. Next, after calcination at 500 ° C. for 3 hours in a muffle furnace, cooling, and lightly pulverizing, 9.3 g of an integrated titanium dioxide composite (3-3) [MW: 79.9, ammonium sulfate is not included in the calculation of molecular weight] (Yield 77.5%) was obtained. This integrated titanium dioxide composite (3-3) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

3.3 Preparation of Petri dish (3-4) with Integrated Titanium Dioxide Composite (3-3) and Determination of Installation Position in Irradiation Box The same procedure as in Example 1 was performed.

3.4 Preparation of a mixed gas containing 200 ppm of ethylene and preparation of a mixed gas of 5 ppm of ethylene in a quartz cell (3-5) containing a petri dish (3-4) containing an integrated powder sample As in Example 1. Went to.

3.5 Measurement of ethylene concentration after leaving titanium dioxide composite in dark place Petri dish with integrated titanium dioxide composite (3-4), 5ppm ethylene gas, mixed gas of argon 80% oxygen 20% The quartz cell (3-5) was placed in a dark place, and the ethylene concentration after 60 minutes and 90 minutes was measured. As shown in Table 1, they were 5.0 ppm and 5.0 ppm, respectively.

3.6 Measurement of Ethylene Concentration when Titanium Dioxide Composite is Irradiated with Daylight White Fluorescent Lamp Next, Petri dish containing titanium dioxide composite (3-4), 5 ppm ethylene gas, mixed gas of argon 80% oxygen 20% Place the quartz cell (3-5) left in the dark in the above position at an illuminance of 500 Lux in the irradiation box, and use aluminum foil for the central part 1/2 of one 20-watt daylight white fluorescent lamp. What was wound and shielded and the light emitting part was halved was placed on the upper part of the irradiation box and turned on. The ethylene-containing mixed gas in the quartz cell (3-5) was irradiated with daylight white fluorescent light. At this time, the ethylene concentration in the quartz cell (3-5) was extracted with a syringe through a septum after 60 minutes, 120 minutes, and 180 minutes of irradiation with a fluorescent lamp, and a gas chromatograph (manufactured by GL Sciences, GC353B type FID). The ethylene concentration was measured with a gas chromatograph, column: Porapak Q, column temperature 110 ° C. As shown in Table 1, the measurement results were 4.5 ppm, 3.9 ppm, and 3.5 ppm, respectively.

4.1 Preparation of small particle size titanium dioxide composite {TiO ₂ ((NH ₄ ) ₂ SO ₄ ) _0.08 } (4-1-2) having an anatase type crystal structure provided by Teika Co., Ltd. White titanium dioxide AMT-100 {(4-1-1), particle size 6 nm, specific surface area 260 m ^{2 /} g} 10.0 g (125 mmol) was put in a magnetic petri dish, and then ammonium sulfate (Wako Pure Chemical Industries, Ltd.) , (NH ₄ ) ₂ SO ₄ , MW: 132.14) 1.3 g (10 mmol, 8 mol% with respect to titanium dioxide) and 10 ml of water were added in a homogeneous solution, mixed well, and impregnated with ammonium sulfate. And dried at about 80 ° C. for about 2 hours. Next, after calcination in a muffle furnace at 500 ° C. for 3 hours and cooling, 9.3 g of titanium dioxide (4-1-2) [MW: 79.9, ammonium sulfate is not included in the calculation of molecular weight] containing pulverized ammonium sulfate Yield: 82.3%) was obtained. This titanium dioxide containing ammonium sulfate (4-1-2) was confirmed to have an anatase type crystal structure from the measurement result of an X-ray diffractometer (XRD).

4.2 Adjustment of large particle size titanium dioxide composite {TiO ₂ ((NH ₄ ) ₂ SO ₄ ) _0.08 } (4-2-2) Having anatase type crystal structure provided by Takeca Co., Ltd. White titanium dioxide JA-1 {(4-2-1), particle size 180 nm, specific surface area 9 m ^{2 /} g} 10.0 g (125 mmol) was put in a magnetic petri dish, and then ammonium sulfate (Wako Pure Chemical Industries, Ltd.) , (NH ₄ ) ₂ SO ₄ , MW: 132.14) 1.3 g (10 mmol, 8 mol% with respect to titanium dioxide) and 10 ml of water were added in a homogeneous solution, mixed well, and impregnated with ammonium sulfate. And dried at about 80 ° C. for about 2 hours. Next, after calcination in a muffle furnace at 500 ° C. for 3 hours and cooling, 9.5 g of titanium dioxide (4-2-2) [MW: 79.9, ammonium sulfate is not included in the calculation of molecular weight] containing pulverized ammonium sulfate Yield: 84.1%) was obtained. The titanium dioxide containing ammonium sulfate (4-2-2) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

4.3 Integration of small particle size titanium dioxide composite (4-1-2) and large particle size titanium dioxide composite (4-2-2) Small particles as described in 4.1 and 4.2 1.0 g of the titanium dioxide composite (4-1-2) having a diameter and 9.0 g of the titanium dioxide composite (4-2-2) having a large particle diameter are placed in a magnetic petri dish and sufficiently uniform. After stirring, the mixture is baked in a muffle furnace at 600 ° C. for 3 hours and cooled, and then blown with cool air from a dryer to blow off fine powder of the titanium dioxide composite to obtain a titanium dioxide composite (4-1-2) having a small particle diameter. An integrated product (4-3) of a titanium dioxide composite (4-2-2) having a large particle size was prepared. The yield was 9.6 g (yield 96.0%), and it was confirmed from an X-ray diffractometer (XRD) measurement result that it had an anatase type crystal structure.

4.4 Preparation of Petri dish (4-4) with Integrated Titanium Dioxide Composite (4-3) and Determination of Installation Position in Irradiation Box The same procedure as in Example 1 was performed.

4.5 Preparation of a mixed gas containing 200 ppm of ethylene and preparation of a mixed gas of 5 ppm of ethylene in a quartz cell (4-5) containing an integrated petri dish (4-4) containing a powder sample Went to.

4.6 Measurement of Ethylene Concentration after Titanium Dioxide Complex Left in the Dark Petri dish with integrated titanium dioxide complex (4-4), 5 ppm ethylene gas, mixed gas of argon 80% oxygen 20% When the quartz cell (4-5) was placed in a dark place and the ethylene concentration after 60 minutes and 90 minutes passed was measured, it was 5.0 ppm and 4.9 ppm, respectively, as shown in Table 1.

4.7 Measurement of Ethylene Concentration when Titanium Dioxide Composite is Irradiated with White White Fluorescent Lamp Next, Petri dish with titanium dioxide composite (4-4), 5 ppm ethylene gas, mixed gas of argon 80% oxygen 20% Place the quartz cell (4-5) left in the dark in the above position at an illuminance of 500 Lux in the irradiation box, and use aluminum foil for the center part of one 20-watt daylight white fluorescent lamp. What was wound and shielded and the light emitting part was halved was placed on the irradiation box and turned on, and the mixed gas containing ethylene in the quartz cell (4-5) was irradiated with light from a daylight fluorescent lamp. At this time, the ethylene concentration in the quartz cell (4-5) was extracted with a syringe through a septum after 60 minutes, 120 minutes, and 180 minutes of irradiation with a fluorescent lamp, and a gas chromatograph (GC353B type FID, manufactured by GL Sciences Inc.) was extracted. The ethylene concentration was measured with a gas chromatograph, column: Porapak Q, column temperature 110 ° C. As shown in FIG. 1 and Table 1, the measurement results were 4.7 ppm, 4.3 ppm, and 4.0 ppm, respectively.

5.1 Titanium dioxide composite with small particle size {TiO ₂ ((NH ₄ ) ₂ SO ₄ ) _0.08 } (5-2-1)
What was adjusted in Example 4 was used.

5.2 Titanium dioxide composite {TiO ₂ ((NH ₄ ) ₂ SO ₄ ) _0.08 } (5-2-2) having a large particle size
What was adjusted in Example 4 was used.

5.3 Integration of small particle size titanium dioxide composite (5-2-1) and large particle size titanium dioxide composite (5-2-2) Small particles as described in 5.1 and 5.2 2.0 g of the titanium dioxide composite (5-2-1) having a diameter and 8.0 g of the titanium dioxide composite (5-2-2) having a large particle diameter are placed in a magnetic petri dish and sufficiently uniform. After stirring, after baking and cooling in a muffle furnace at 600 ° C. for 3 hours, a cool air of a dryer is applied to blow off fine powder of the titanium dioxide composite, and the titanium dioxide composite (5-2-1) having a small particle diameter An integrated product (5-3) of a titanium dioxide composite (5-2-2) having a large particle size was prepared. The yield was 9.6 g (yield 96.0%), and it was confirmed from an X-ray diffractometer (XRD) measurement result that it had an anatase type crystal structure.

5.4 Preparation of Petri dish (5-4) with Integrated Titanium Dioxide Composite (5-3) and Determination of Installation Position in Irradiation Box The same procedure as in Example 1 was performed.

5.5 Preparation of a mixed gas containing 200 ppm of ethylene and preparation of a mixed gas of 5 ppm of ethylene in a quartz cell (5-5) containing a petri dish (5-4) containing an integrated powder sample As in Example 1. Went to.

5.6 Measurement of ethylene concentration after leaving titanium dioxide composite in dark place Petri dish with integrated titanium dioxide composite (5-4), 5ppm ethylene gas, argon 80% oxygen, 20% oxygen mixed gas entered When the quartz cell (5-5) was placed in a dark place and the ethylene concentration after 60 minutes and 90 minutes passed was measured, as shown in Table 1, they were 4.9 ppm and 4.9 ppm, respectively.

5.7 Measurement of the concentration of ethylene when the titanium dioxide composite was irradiated with daylight white fluorescent lamp Next, a petri dish containing the titanium dioxide composite (5-4), 5 ppm ethylene gas, argon 80% oxygen, 20% mixed gas Place the quartz cell (5-5) left in the dark place in the irradiation box at an illuminance of 500 Lux and place the central part 1/2 of one 20-watt daylight white fluorescent lamp with aluminum foil. What was rolled up and shielded and the light emitting part was halved was placed on the irradiation box and turned on, and the ethylene-containing mixed gas in the quartz cell (5-5) was irradiated with daylight white fluorescent light. At this time, the ethylene concentration in the quartz cell (5-5) was extracted with a syringe through a septum after 60 minutes, 120 minutes, and 180 minutes of irradiation with a fluorescent lamp, and a gas chromatograph (manufactured by GL Sciences, GC353B type FID). The ethylene concentration was measured with a gas chromatograph, column: Porapak Q, column temperature 110 ° C. As shown in Table 1, the measurement results were 4.5 ppm, 3.9 ppm, and 3.5 ppm, respectively.

Comparative Example 1

  Using titanium dioxide JA-1 manufactured by Teika Co., Ltd. used for the preparation of a titanium dioxide composite having a large particle size in Example 1, ethylene at the time of day white fluorescent lamp irradiation was the same as 1.3 or less in Example 1. Concentration was measured. As shown in Table 1, the measured values after 60 minutes and 90 minutes are 5.0 ppm and 4.9 ppm when left in the dark, respectively. Min and after 180 minutes, it was 5.0 ppm.

Comparative Example 2

  An integrated product of small particle size titanium dioxide and large particle size titanium dioxide (2.2) prepared in Example 2 (small particle size titanium dioxide / large particle size titanium dioxide = 2/8, impregnation with ammonium sulfate None) was used to measure the ethylene concentration during daylight white fluorescent lamp irradiation in the same manner as in Example 1 below 1.3. The results are as shown in Table 1. As shown in Table 1, the measured values after 60 minutes and 90 minutes are 5.0 ppm and 5.0 ppm when left in the dark, respectively. Min and after 180 minutes, it was 4.9 ppm.

Comparative Example 3

6.1 Integration of small particle size titanium dioxide and large particle size titanium dioxide Integrated material of small particle size titanium dioxide and large particle size titanium dioxide prepared in Example 2 (2.2) (small particle size Diameter titanium dioxide / large particle diameter titanium dioxide = 2/8) was used.

6.2 Adjustment of Integrated Titanium Dioxide Composite {TiO ₂ ((NH ₄ ) ₂ SO ₄ ) _0.25 } (6-3) The small particle size titanium dioxide and the large particle size adjusted in Example 2 10.0 g (125 mmol) of an integrated product of titanium dioxide (2.2) (small particle size titanium dioxide / large particle size titanium dioxide = 2/8) was put into a magnetic petri dish, and then ammonium sulfate (Wako Pure Chemical Industries, Ltd.) Add a homogeneous solution of 4.1 g (31.25 mmol, 25 mol% with respect to titanium dioxide) of (NH ₄ ) ₂ SO ₄ , MW: 132.14) manufactured by Kogyo Co., Ltd. and 10 ml of water, and mix well. After impregnating with ammonium sulfate, it was dried at about 80 ° C. for about 2 hours. Next, after calcining in a muffle furnace at 500 ° C. for 3 hours and cooling, pulverized and integrated titanium dioxide composite (6-3) containing ammonium sulfate (MW: 79.9, ammonium sulfate is not included in the calculation of molecular weight). 2 g (yield: 65.2%) was obtained. This integrated titanium dioxide composite (6-3) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

6.3 Preparation of Petri dish (6-4) with Integrated Titanium Dioxide Composite (6-3) and Determination of Installation Position in Irradiation Box The same procedure as in Example 1 was performed.

6.4 Preparation of mixed gas containing 200 ppm of ethylene and preparation of mixed gas of 5 ppm of ethylene in quartz cell (6-5) containing petri dish (6-4) with integrated titanium dioxide composite powder sample Performed as in Example 1.

6.5 Measurement of ethylene concentration after leaving the titanium dioxide composite in the dark Petri dish with integrated titanium dioxide composite (6-4), 5 ppm ethylene gas, argon 80% oxygen, 20% oxygen mixed gas The quartz cell (6-5) was placed in a dark place and the ethylene concentration after 60 minutes and 90 minutes was measured. As shown in Table 1, they were 5.0 ppm and 4.9 ppm, respectively.

6.6 Measurement of ethylene concentration when titanium dioxide composite is irradiated with daylight white fluorescent lamp Next, petri dish with titanium dioxide composite (6-4), mixed gas of 5 ppm ethylene gas, argon 80% oxygen 20% Place the quartz cell (6-5) left in the dark place with the illuminance of 500 Lux in the irradiation box, and use aluminum foil for the central part 1/2 of one 20-watt daylight white fluorescent lamp. What was wound and shielded and the light emitting part was halved was placed on the irradiation box and turned on, and the mixed gas containing ethylene in the quartz cell (6-5) was irradiated with daylight white fluorescent light. At this time, the ethylene concentration in the quartz cell (6-5) was extracted with a syringe through a septum after 60 minutes, 120 minutes, and 180 minutes of irradiation with a fluorescent lamp, and gas chromatograph (manufactured by GL Sciences, GC353B type FID). The ethylene concentration was measured with a gas chromatograph, column: Porapak Q, column temperature 110 ° C. As shown in FIG. 1 and Table 1, the measurement results were 4.9 ppm, 4.7 ppm, and 4.5 ppm, respectively.

Comparative Example 4

7.1 Preparation of small-diameter titanium dioxide composite {TiO ₂ ((NH ₄ ) ₂ SO ₄ ) _0.25 } (7-1-2) having anatase type crystal structure provided by Takeca Co., Ltd. White titanium dioxide AMT-100 {(7-1-1), particle size 6 nm, specific surface area 260 m ^{2 /} g} 10.0 g (125 mmol) was put in a magnetic petri dish, and then ammonium sulfate (Wako Pure Chemical Industries, Ltd.) , (NH ₄ ) ₂ SO ₄ , MW: 132.14) 4.1 g (31.25 mmol, 25 mol% with respect to titanium dioxide) and 10 ml of water in a homogeneous solution were mixed well and impregnated with ammonium sulfate. And then dried at about 80 ° C. for about 2 hours. Next, after firing in a muffle furnace at 500 ° C. for 3 hours and cooling, 9.0 g of titanium dioxide (7-1-2) containing pulverized ammonium sulfate (MW: 79.9, ammonium sulfate is not included in the calculation of molecular weight) ( Yield: 63.8%). It was confirmed that the titanium dioxide containing ammonium sulfate (7-1-2) has an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

7.2 Preparation of large-diameter titanium dioxide composite {TiO ₂ ((NH ₄ ) ₂ SO ₄ ) _0.25 } (7-2-2) having an anatase type crystal structure provided by Teika Co., Ltd. White titanium dioxide JA-1 {(7-2-1), particle size 180 nm, specific surface area 9 m ^{2 /} g} 10.0 g (125 mmol) was put in a magnetic petri dish, and then ammonium sulfate (Wako Pure Chemical Industries, Ltd.) , (NH ₄ ) ₂ SO ₄ , MW: 132.14) 4.1 g (31.25 mmol, 25 mol% with respect to titanium dioxide) and 10 ml of water in a homogeneous solution were mixed well and impregnated with ammonium sulfate. And then dried at about 80 ° C. for about 2 hours. Next, after calcination in a muffle furnace at 500 ° C. for 3 hours and cooling, pulverization and titanium dioxide (7-2-2) containing ammonium sulfate [MW: 79.9, ammonium sulfate is not included in the calculation of molecular weight] (9.3 g) Yield: 66.0%). It was confirmed that the titanium dioxide containing ammonium sulfate (7-2-2) has an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

7.3 Integration of small particle size titanium dioxide composite (7-1-2) and large particle size titanium dioxide composite (7-2-2) Small particles as described in 7.1 and 7.2 2.0 g of the titanium dioxide composite (7-1-2) having a large diameter and 8.0 g of the titanium dioxide composite (7-2-2) having a large particle diameter are placed in a magnetic petri dish and sufficiently uniform. After stirring, after baking and cooling in a muffle furnace at 600 ° C. for 3 hours, the cold air of a dryer is applied, the fine powder of the titanium dioxide composite is blown off, and the titanium dioxide composite (7-1-2) having a small particle diameter is obtained. An integrated product (7-3) of a titanium dioxide composite (7-2-2) having a large particle size was prepared. The yield was 9.3 g (yield 93.0%), and it was confirmed from an X-ray diffractometer (XRD) measurement result that it had an anatase type crystal structure.

7.4 Preparation of Petri dish (7-4) with Integrated Titanium Dioxide Composite (7-3) and Determination of Installation Position in Irradiation Box The same procedure as in Example 1 was performed.

7.5 Preparation of a mixed gas containing 200 ppm of ethylene and preparation of a mixed gas of 5 ppm of ethylene in a quartz cell (7-5) containing a petri dish (7-4) with an integrated powder sample As in Example 1. went.

7.6 Measurement of ethylene concentration after leaving the titanium dioxide composite in the dark Petri dish with integrated titanium dioxide composite (7-4), 5 ppm ethylene gas, argon 80% oxygen, 20% oxygen mixed gas The quartz cell (7-5) was placed in a dark place and the ethylene concentration after 60 minutes and 90 minutes was measured. As shown in Table 1, it was 5.0 ppm and 5.0 ppm, respectively.

7.7 Measurement of Ethylene Concentration when Irradiating Titanium Dioxide Complex with Daylight White Fluorescent Lamp Next, Petri dish with titanium dioxide complex (7-4), mixed gas of 5 ppm ethylene gas, argon 80% oxygen 20% Place the quartz cell (7-5) that is left in the dark place with the illuminance of 500 Lux in the irradiation box, and use aluminum foil for the central part 1/2 of one 20-watt daylight white fluorescent lamp. What was wound and shielded and the light emitting part was halved was placed on the top of the irradiation box and turned on, and the ethylene-containing mixed gas in the quartz cell (7-5) was irradiated with daylight white fluorescent light. At this time, the ethylene concentration in the quartz cell (7-5) was extracted with a syringe through a septum after 60 minutes, 120 minutes, and 180 minutes of irradiation with a fluorescent lamp, and gas chromatograph (manufactured by GL Sciences, GC353B type FID). The ethylene concentration was measured with a gas chromatograph, column: Porapak Q, column temperature 110 ° C. As shown in Table 1, the measurement results were 4.9 ppm, 4.7 ppm, and 4.6 ppm, respectively.

Comparative Example 5

8.1 Preparation of Integration (8-2) of Small Particle Size Titanium Dioxide and Large Particle Size Titanium Dioxide White Titanium Dioxide AMT-100 {(8 -1-1), 0.3 g having a particle size of 6 nm and a specific surface area of 260 m ² / g} was put in a magnetic petri dish, and then white titanium dioxide JA- having an anatase type crystal structure also provided by Teika Co., Ltd. 9.7 g of 1 {(8-1-2), particle size 180 nm, specific surface area 9 m ² / g} is placed in a magnetic petri dish, stirred well to be uniform, and baked in a muffle furnace at 600 ° C. for 3 hours. After cooling, the mixture was lightly pulverized to obtain 9.9 g (yield 99.0%) of the integrated product (8-2). This integrated titanium dioxide (8-2) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

8.2 Adjustment of Integrated Titanium Dioxide Composite {TiO ₂ ((NH ₄ ) ₂ SO ₄ ) _0.08 } (8-3) To 10 g of integrated titanium dioxide (8-2), ammonium sulfate (Wako Pure Chemical Industries, Ltd.) A uniform solution of 1.3 g (10 mmol, 8 mol% with respect to titanium dioxide) of (NH ₄ ) ₂ SO ₄ , MW: 132.14) and 10 ml of water was added, mixed well, and impregnated with ammonium sulfate. And dried at about 80 ° C. for about 2 hours. Next, after calcination at 500 ° C. for 3 hours in a muffle furnace, cooling, and lightly pulverizing, 9.8 g of integrated titanium dioxide composite (8-3) [MW: 79.9, ammonium sulfate is not included in the calculation of molecular weight] (Yield 86.7%) was obtained. This integrated titanium dioxide (8-3) was confirmed to have an anatase type crystal structure from the measurement result of the X-ray diffractometer (XRD).

8.3 Preparation of Petri dish (8-4) with Integrated Titanium Dioxide Composite (8-3) and Determination of Installation Position in Irradiation Box The same procedure as in Example 1 was performed.

8.4 Preparation of mixed gas containing 200 ppm of ethylene and preparation of mixed gas of 5 ppm of ethylene in quartz cell (8-5) containing petri dish (8-4) with integrated titanium dioxide composite powder sample Performed as in Example 1.

8.5 Measurement of ethylene concentration after leaving the titanium dioxide composite in the dark Petri dish with integrated titanium dioxide composite (8-4), 5 ppm ethylene gas, 80% argon, 20% oxygen mixed gas entered When the quartz cell (8-4) was placed in a dark place and the ethylene concentration after 60 minutes and 90 minutes passed was measured, as shown in Table 1, they were 4.9 ppm and 5.0 ppm, respectively.

8.6 Measurement of the concentration of ethylene when the titanium dioxide composite is irradiated with a daylight fluorescent lamp Next, a petri dish containing the titanium dioxide composite (8-4), a mixed gas of 5 ppm ethylene gas, argon 80% oxygen 20% Place the quartz cell (8-5) left in the dark in the above position at an illuminance of 500 Lux in the irradiation box, and use aluminum foil for the central part 1/2 of one 20-watt daylight white fluorescent lamp. What was rolled and shielded and the light emitting part was halved was placed on the irradiation box and turned on, and the ethylene-containing mixed gas in the quartz cell (8-5) was irradiated with daylight white fluorescent light. At this time, the ethylene concentration in the quartz cell (8-5) was extracted with a syringe through a septum after 60 minutes, 120 minutes, and 180 minutes of irradiation with a fluorescent lamp, and gas chromatograph (manufactured by GL Sciences, GC353B type FID). The ethylene concentration was measured with a gas chromatograph, column: Porapak Q, column temperature 110 ° C. As shown in FIG. 1 and Table 1, the measurement results were 4.9 ppm, 4.8 ppm, and 4.8 ppm, respectively.

Comparison of Examples 1-5 and Comparative Examples 1-5 In Examples 1-5, during the daylight white fluorescent lamp irradiation, ethylene was clearly decomposed and the ethylene concentration decreased with the passage of time. In 2 (small particle size / large particle size = 2/8, titanium dioxide was integrated after being integrated with ammonium dioxide), the decrease in ethylene concentration was the largest. Due to the original nature of the photocatalyst, if irradiation continues, it is expected that ethylene will continue to decompose and be able to handle practical use sufficiently.
On the other hand, in the comparative example, when ammonium sulfate is not combined (Comparative Examples 1 and 2), no effect is recognized. When Comparative Examples 3 and 4 were impregnated with 25 mol% ammonium sulfate, a decrease in ethylene concentration was observed, but the effect was small. Therefore, it was confirmed that the titanium dioxide composite of the present invention showed activity when irradiated with a daylight white fluorescent lamp having a low illuminance of 500 lux, and had the ability to decompose ethylene. It seems that the photocatalytic effect is further increased if the illuminance is increased.

  The highly active photocatalyst in which the titanium dioxide composite having a small particle size and the titanium dioxide composite having a large particle size are integrated is a general substance even without irradiation of light from a special lamp including sunlight or ultraviolet rays. It is activated by the light of a white fluorescent lamp used for lighting, and exhibits practically sufficient ethylene decomposition performance. In addition, since the amount of the very expensive anatase type fine particle titanium dioxide can be reduced, it can be produced at a low cost. Therefore, in order to efficiently decompose ethylene, which is generated during storage of agricultural products, cut flowers, etc., indoors or in vehicles, it is extremely useful for maintaining their quality and is economically superior.

  Ultraviolet / visible absorption spectrum of a titanium dioxide composite obtained by impregnating 8% by mole of ammonium sulfate in a small particle size anatase type titanium dioxide (AMT-100) and calcining.

Claims (9)

A highly active photocatalyst excellent in photolysis of ethylene, wherein a titanium dioxide composite produced from two or more types of titanium dioxide and ammonium sulfate having different particle diameters is integrated. The highly active photocatalyst according to claim 1, wherein the titanium dioxide has an anatase type crystal structure. The high activity photocatalyst according to claim 1 or 2, wherein the particle diameter of titanium dioxide having a small particle diameter is less than 8 nm, and the particle diameter of titanium dioxide having a larger particle diameter is 50 nm or more. The highly active photocatalyst according to claim 1, wherein the titanium dioxide composite is obtained by impregnating titanium dioxide with ammonium sulfate. The highly active photocatalyst according to any one of claims 1 to 4, wherein the composite of any particle size has an impregnation amount of ammonium sulfate with respect to titanium dioxide of 1 to 20 mol%. 6. The highly active photocatalyst according to claim 1, wherein the weight ratio of the composite of titanium dioxide having a small particle size and the titanium dioxide composite having a large particle size is 5/95 to 40/60. The method for producing a highly active photocatalyst according to any one of claims 1 to 6, wherein a titanium dioxide composite produced from two or more types of titanium dioxide and ammonium sulfate having different particle diameters is baked and integrated. The method for producing a highly active photocatalyst according to claim 7, wherein two or more kinds of titanium dioxides having different particle diameters are calcined and integrated, and then the titanium dioxide composite formed by impregnation with ammonium sulfate is calcined. The method for producing a highly active photocatalyst according to claim 7, wherein a titanium dioxide composite formed by impregnating ammonium sulfate with each of two or more types of titanium dioxide having different particle diameters is baked and integrated.

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