WO2002074060A1

WO2002074060A1 - Method of promoting germination

Info

Publication number: WO2002074060A1
Application number: PCT/JP2002/002665
Authority: WO
Inventors: Shinichi Sugihara; Tatsuhiko Ihara
Original assignee: Ecodevice Laboratory Co., Ltd.
Priority date: 2001-03-21
Filing date: 2002-03-20
Publication date: 2002-09-26
Also published as: JP2004357501A

Abstract

A method of promoting the germination of seeds characterized by continuously or intermittently irradiating the seeds with light involving visible light in the coexistence of a photocatalyst exerting its activity under the action of light having a wavelength of 420 nm or longer (i.e., a visible light-responsive photocatalyst) and water.

Description

Specification

Germination promotion method Technical field

The present invention relates to a method for promoting seed germination. More specifically, the present invention relates to a method for promoting seed germination, in which germination of seeds is promoted and a germination rate is improved by utilizing a visible light-responsive photocatalyst. Background art

Conventionally, when germinating seeds, first, bacteria and viruses contaminating the seeds are sterilized using an appropriate chemical, then the seeds are immersed in water and sufficiently absorbed in water, and then subjected to the specified temperature and humidity. Germinated below. However, seeds (hard fruits) whose outer shell (seed coat) does not allow water to permeate cannot absorb water and may not germinate. Also, even if the seed coat is impervious to oxygen, the seed will not germinate easily. Therefore, seed germination is not constant, and it takes a considerable time for all seeds to germinate and obtain seedlings, which has been an obstacle to automation of seedling cultivation. In order to improve this, a method has been used in which the seed coat is damaged with a strong acid such as sulfuric acid, or the seed coat is cut off with scissors or the like to promote germination. However, in order to obtain a constant germination rate using, for example, a strong acid, a large-scale apparatus for controlling the concentration of the strong acid or controlling the contact time between the strong acid and the seed is required. Therefore, there has been a problem that the resulting seeds are expensive. And today, even after sterilizing the seeds, no drug is attached to the seeds, Drug-free seeds are required. To solve such a conventional problem, a method of promoting seed germination and germination, in which seed germination is promoted and the germination rate is improved, and at the same time, seeds are also sterilized, has been proposed (Japanese Patent Laid-Open Publication No.

No. 5-2118808). This method is characterized by immersing the seeds in ozone water having an ozone concentration of 5 ppm or more. However, since ozone water is used, there is a problem in safety. Therefore, an object of the present invention is to provide a seed germination promotion method that is highly safe, promotes seed germination, and improves the germination rate. Disclosure of the invention

The present invention provides a photocatalyst (visible light responsive photocatalyst) which is active by the action of light having a wavelength of 420 nm or more, or a seed containing a material containing the visible light responsive photocatalyst and water in the presence of water. A method for promoting germination of seeds, comprising continuously or intermittently irradiating light containing BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an ESR spectrum of the visible light responsive material of the present invention (Reference Example 1) measured at 77 K in a vacuum. The upper row is the spectrum under black, and the middle row is the spectrum under irradiation of light having a wavelength of 420 nm or more (the light of less than 420 nm is cut off of the light of the mercury lamp). The lower part shows the spectrum when the light of a mercury lamp is irradiated without cutting off the light of less than 420 nm. FIG. 2 is an ESR spectrum of the visible light responsive material of the present invention (Reference Example 1) measured at room temperature in a vacuum. The upper row shows the spectrum in the dark. The middle row shows the spectrum under irradiation with light having a wavelength of 420 nm or more (the light of the mercury lamp cuts off the light of less than 420 nm). The lower row shows the spectrum. , A spectrum when a light of a mercury lamp is irradiated without cutting off light of less than 420 nm.

Figure 3 shows the XRD measurement results of the product of Reference Example 1 (upper) and the hydrolyzate (dried at 50 ° C) (lower).

FIG. 4 shows emission spectra of a blue light emitting diode (NSPB), a green light emitting diode (NSPG), and a white light emitting diode (NSPW).

Figure 5 shows the light of the product of Example 4 (visible light responsive material) in a vacuum at 77Κ, which has a wavelength of 420 ηm or more (of the mercury lamp, the light of less than 420 nm is cutoff). This is the ESR spectrum measured under irradiation.

Figure 6 shows the light of the product of Reference Example 5 (visible light responsive material) having a wavelength of 77 mm, 420 ηm or more (in a mercury lamp, light of less than 420 nm is cut off in vacuum). The ESR spectrum measured under the irradiation of).

Figure 7 shows the light of the product of Reference Example 6 (visible light responsive material) in vacuum at 77 K :, light with a wavelength of 420 ηm or more (of the mercury lamp light, light of less than 420 nm is cut off). The ESR spectrum measured under the irradiation of.

Figure 8 shows the ESR spectrum of the sample (analyze type titanium dioxide) before the plasma treatment.

Figure 9 shows the ESR spectrum of the sample (anatase type titanium dioxide) after the plasma treatment. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail.

Seeds that can be used in the present invention are not particularly limited, and can be freely selected. For example, cereals such as rice and wheat, flowers such as chrysanthemums, and seeds of vegetables such as pomegranates are included. However, in the present invention, a visible light-responsive photocatalyst under visible light irradiation is used even for seeds such as seeds that cannot absorb water due to solid fruit or seeds that do not show an enormous number of embryos, or seeds whose seed coat does not transmit oxygen. Thereby, germination of seeds that are difficult to germinate can be promoted and the germination rate can be improved. At the same time, seeds can be sterilized. The visible light responsive photocatalyst used in the present invention is, for example, a titanium oxide containing at least anatase-type titanium oxide, and is measured in a vacuum at 77 K under irradiation of light having a wavelength of 420 nm or more at 77 K. In the obtained ESR, the main signal having the g value of 2.004 to 2.007 (the signal having the strongest intensity) and the g values of 1.895 to 1.8966 and 2.02 were obtained. It can be a visible light responsive material in which two secondary signals (4, a signal with lower intensity than the main signal) are observed. Furthermore, in this visible light responsive material, the above three signals (main signal and two sub-signals) are slightly observed or substantially observed in vacuum at 77 K: in darkness. Not done.

Here, the light having a wavelength of 420 nm or more used for ESR is a light from a high-pressure mercury lamp (for example, 500 W), and a light having a wavelength shorter than 420 nm is cut. This is light obtained by passing through a filter (L-42).

In addition, this visible light responsive material has a wavelength of 450 nm or more at 77 K in vacuum. ESR measured under illumination of light obtained by transmitting light having a wavelength (eg, a filter (GG455) that cuts light from a Xe lamp (eg, 150 W) that cuts light with a wavelength shorter than 455 nm). Also, the main signal (the strongest signal) with a g-value of 2.004-2.007 and the two sub-signals (g-values between 1.985 and 1.986 and 2.024) Signal that is lower in intensity than the main signal). Alternatively, the visible light responsive material used in the present invention can be, for example, a visible light photocatalyst composed of titanium dioxide having a stable oxygen defect described in W000 / 10706. The ESR spectrum of the visible-type photocatalyst described in WO00 / 107O6 has only a signal with a g-value force of S2.003 to 2.004 in ESR measured under black at 77 K in vacuum. The visible light responsive material and the visible light photocatalyst described in TOOO / 10706 are different from each other in a spectrum different from that of the visible light photocatalyst described in TOOO / 10706. It has activity against visible light having a wavelength exceeding that. Hereinafter, the visible light responsive material will be described.

The visible light responsive material used in the present invention is preferably titanium oxide containing anatase-type titanium oxide as a main component, and may further contain amorphous titanium oxide. Alternatively, rutile-type titanium oxide may be further included. Also, the anatase type titanium oxide does not necessarily have to have high crystallinity. Further, in the titanium oxide constituting the visible light responsive material, titanium and oxygen can have a non-stoichiometric ratio. Specifically, the amount of oxygen with respect to titanium is reduced to titanium dioxide. May be less than the stoichiometric ratio (theoretical value: 2.00). The titanium oxide in the visible light responsive material may have, for example, a molar ratio of oxygen to titanium of less than 2.00, for example, 1,00 to 1.99, or 1.50 to 1.99. it can. The molar ratio of oxygen to titanium in the titanium oxide in the visible light responsive material can be measured using, for example, X-ray photoelectron spectroscopy. Figure 1 shows a typical ESR spectrum of the above visible light responsive material measured at 77 K in vacuum. In the figure, the upper row shows the spectrum in the dark, and the middle row shows the spectrum under the irradiation of light having a wavelength of 42 O nm or more (of the mercury lamp light, the light of less than 420 nm is cutoff). is there. The lower part shows the spectrum when the light of the mercury lamp is irradiated without cutting off the light of less than 420 nm. The upper, middle, and lower rows are the results measured under the same gain (GAIN). In the upper spectrum of Fig. 1, the main signals with g values of 2.004 to 2.007 are slightly observed, but the g values are 1.985 to 1.986 and 2.024. Two sub-signals are practically not observed. Furthermore, when comparing the spectrum in the upper part of FIG. 1 with the spectrum in the middle part, it is clear that the main signal whose g value is 2.004 to 2.007 and the g value is 1.985 to The two side signals, 1.986 and 2.024, are significantly stronger than in the upper spectrum. In addition, comparing the spectra in the middle and lower rows of Fig. 1, it is clear that the main signals with g values of 2.004 to 2.007 and the g values of 1.985-1.986 and 2.024. The intensities of any two sub-signals are substantially the same whether or not the irradiation light contains light of less than 420 nm. Furthermore, in the above visible light responsive material, as shown in Fig. 2, the main signal having a _g value of 2.004 to 2.007 is observed in a vacuum, at room temperature, and in darkness. Two side signals with values between 1.985 and 1.986 and 2,024 are virtually not observed. Further, in an ESR under irradiation of light having a wavelength of 420 nm or more in a vacuum and at room temperature and under irradiation of a mercury lamp which does not cut off light of less than 420 nm, the above three signals should be measured. I understand. In Fig. 2, the upper row shows the spectrum in the dark, and the middle row shows the spectrum under irradiation with light having a wavelength of 420 nm or more (of the mercury lamp light, the light of less than 420 nm is cut off). It is a kutor. The lower part shows the spectrum when the light of a mercury lamp is irradiated without cutting off the light of less than 420 nm. The upper, middle, and lower rows are the results measured under the same gain (GAIN). The visible light responsive material has a g-value of 2.0009 to 2.010 in addition to the above signal, when measured in a vacuum at 77 K under irradiation with light having a wavelength of 420 nm or more. It can also have certain side signals. The side signal with a g value of 2.00-9.010 is shown in the middle ESR spectrum of FIG. The visible light responsive material is a material having a characteristic ESR signal as described above, but at the same time, is also a colored material, and has a reflectance of 1 (or 600 nm) for light having a wavelength of 600 nm. 100%), the reflectance for light with a wavelength of 450 nm is 0.85 (or 85%) or less, preferably 0.80 (or 80%). It is more preferably 0.70 (or 70%) or less. The larger the coloration, the stronger the visible light response activity tends to be. The reflectivity here is the result measured by a spectrophotometer. Although the reflectance can be measured with a color analyzer, a spectrophotometer is used for the evaluation of the reflectance because of its excellent accuracy. The visible light responsive material has a characteristic ESR signal as described above, and additionally has NO oxidation activity with respect to light in the visible light region. Specifically, NO oxidation activity is exhibited by irradiating visible light having a wavelength of at least 520 nm or less. In a more preferable material, NO oxidation activity is exhibited by irradiating visible light having a wavelength of 570 nm or less. The visible light responsive material can be produced using amorphous or imperfect crystalline titanium oxide (including hydrated titanium oxide) and Z or titanium hydroxide as raw materials. This raw material titanium compound can be obtained by a wet method such as a sulfuric acid method or a chloride method. More specifically, the raw material titanium compound can be obtained by hydrolyzing titanium chloride or titanium sulfate with ammonium hydroxide. Alternatively, the starting titanium compound can be obtained by hydrolyzing a titanium alkoxide with water, or can be obtained by hydrolyzing a titanium alkoxide with an aqueous ammonium hydroxide solution. However, from the viewpoint of the raw material price being low, in industrial production, it is preferably obtained by hydrolyzing titanium chloride or titanium sulfate with ammonium hydroxide. Therefore, the case where titanium chloride or titanium sulfate is hydrolyzed with ammonium hydroxide will be described below. You. The hydrolysis is carried out, for example, by continuously or intermittently adding an aqueous solution of ammonium hydroxide to an aqueous solution of titanium chloride or an aqueous solution of titanium sulfate, or continuously or intermittently adding an aqueous solution of titanium chloride or an aqueous solution of titanium sulfate to an aqueous solution of ammonium hydroxide. It can be added intermittently. The concentrations of the aqueous titanium chloride solution, the aqueous titanium sulfate solution, and the aqueous ammonium hydroxide solution can be determined as appropriate. This hydrolysis is suitably performed by adjusting the amount of ammonium hydroxide to be added so that the final pH of the reaction solution is 5 or more. The titanium chloride may be titanium trichloride, titanium tetrachloride, or the like, or a mixture thereof. The hydrolysis can be performed, for example, at a temperature in the range of 0 ° C. to 100 ° C., preferably 20 ° C. to 80 ° C., but the hydrolysis at room temperature has relatively low crystallinity. It may be preferable from the viewpoint that amorphous titanium dioxide can be obtained. The hydrolyzate of titanium chloride or titanium sulfate with ammonium hydroxide is preferably used as a starting titanium compound after washing with water or an aqueous solution of ammonium hydroxide. Washing of the hydrolyzate with water or an aqueous solution of ammonium hydroxide is performed, for example, by filtering a reaction solution containing the hydrolyzate, and further passing water or an aqueous solution of ammonium hydroxide through the hydrolyzate obtained as a filtrate. be able to. This method is preferable because the operation is easy because water or an aqueous solution of ammonium hydroxide can be added to the filtered hydrolyzate as it is and then filtered. The washing of the hydrolyzate with water or an aqueous solution of ammonium hydroxide is performed in addition to the above. For example, the filtrate of the hydrolyzate is suspended again in water or an aqueous solution of ammonium hydroxide, and the resulting suspension It can be performed by filtering the substance. Washing with water or an aqueous solution of ammonium hydroxide can be performed such that the residual amount of ammonium salt such as ammonium chloride or ammonium sulfate generated during the hydrolysis is reduced to an appropriate amount, and can also be performed a plurality of times.

A commercially available amorphous or imperfect crystalline titanium dioxide may be used, for example, imperfect crystalline titanium dioxide such as ST-01 or C-02 manufactured by Ishihara Sangyo. You may. In the above production method, a raw material titanium compound such as amorphous or incompletely crystalline titanium oxide is heated in the presence of ammonia or a derivative thereof. Ammonia may be liquid or gaseous. When using ammonia gas, the raw material titanium compound is heated in an ammonia gas atmosphere. Examples of the ammonia derivative include, for example, ammonium salts such as ammonium hydroxide and ammonium chloride. For example, a raw material titanium compound is heated in the presence of ammonium hydroxide and ammonium chloride. When the raw titanium compound is heated in the presence of ammonia or its derivative, the absorption of light at a wavelength of 45 O nm of the material generated by the heating is larger than that of the raw titanium compound at a wavelength of 45 O nm. This is done by terminating the heating at that point. Usually, the starting titanium compound is white, and the light absorption at a wavelength of 45 O nm is around 10%. On the other hand, when the raw titanium compound is heated in the presence of ammonia or its derivative, it gradually becomes yellow. However, this coloring fades to a peak at a certain point in time, and eventually shows an absorption similar to that of the starting titanium compound. original Depending on the type of titanium compound, the type and amount of coexisting ammonia (derivative), heating temperature, time, etc., the absorption of light at a wavelength of 45 Onm may reach up to around 60%. The characteristics of a visible light responsive material are not uniquely determined by the light absorption intensity at a wavelength of 45 Onm, but when the light absorption at a wavelength of 45 Onm is 15% or more (reflectance 85% or less). This is a material that clearly exhibits visible light responsiveness. Therefore, in the above heat treatment, the reflectance for light having a wavelength of 450 nm is 0.85 (or 85%) when the reflectance for light having a wavelength of 600 nm is 1 (or 100%). Hereinafter, it is preferable to set the conditions to be preferably 0.80 (or 80%) or less, more preferably 0.70 (or 70%) or less. The reflectivity here is the result measured with a spectrophotometer. The heating conditions cannot necessarily be defined only by the temperature. However, the temperature used can be, for example, a temperature in the range of 250 to 550 ° C. NOx removal by light at wavelengths of 420 nm and 470 ηm tends to be relatively high with heating in the range of 300-450 ° C and higher with heating in the range of 325-425 ° C. However, the removal of N 率 x by light at wavelengths of 520 nm and 570 nm tends to be relatively high when heating in the range δΖδ δΟ, and tends to be higher when heating in the range 350-425 ° C. . Accordingly, heating in the range of 350 to 425 ° C. is most preferable in terms of a high NOx removal rate in the visible light region. In addition, the heating time is appropriately 30 minutes or more, preferably 1 hour or more, from the viewpoint that the NOx removal rate with respect to light in the visible light region having wavelengths of 520 nm and 570 nm is improved. . Also, if the heating time is longer than 1 hour, NOx Since there is no significant change in the removal rate, it is at most about 3 hours. This heating can be performed under normal pressure. In addition, the heating time can be appropriately determined based on the absorption of light at a wavelength of 45 O nm of a material generated by heating. The heating can be performed using a rotary kiln, a tunnel kiln, a matsufur kiln, or the like that is generally used in the art. When individual particles of titanium oxide are aggregated or sintered by heating, they may be ground by a pulverizer as necessary. Further, the material obtained by heating as described above can be washed with water or an aqueous solution as needed. This washing may improve the visible light responsiveness of the obtained visible light responsive material in some cases. Further, depending on the conditions, a material having good visible light response may be obtained without washing.

If amorphous or incompletely crystalline titanium oxide (raw titanium compound before heating) is obtained by, for example, hydrolyzing titanium chloride with ammonium hydroxide, a considerable amount of the hydrolyzate is obtained. As a result, it is possible to convert the amorphous or imperfect crystalline titanium dioxide into a visible light responsive material by heating it at a predetermined temperature as described above. . However, even after the heat treatment, an equivalent amount of ammonium chloride may remain in the obtained material. In such a case, washing with water or a suitable aqueous solution may remove ammonium chloride and improve the visible light responsiveness of the visible light responsive material in some cases. Further, in this case, the washing of the material obtained by heating with water or an aqueous solution is performed by washing the water or the aqueous solution separated from the material after the washing; -7) The amount of chloride ion contained in water or aqueous solution separated from the material after washing or in the case of using titanium chloride as a raw material for hydrolyzate or the amount of sulfate ion (hydrolyzing titanium sulfate) It is preferable to reduce the amount of raw material. The above visible light responsive material is usually obtained as a powder. The particle size of the obtained powder can be adjusted by pulverization or the like, if necessary. Further, the material containing the visible light responsive photocatalyst can be an organic coating film, an inorganic coating film, or a fiber, and the visible light responsive photocatalyst powder is prepared by an ordinary method using an organic coating film (for example, a fluororesin coating film or the like). ) Can be produced by mixing it with a resin or a compound which is a raw material of an inorganic coating film or a fiber. The above-mentioned visible light responsive materials include silicon, aluminum, tin, zirconium, antimony, phosphorus, platinum, gold, silver, copper, iron, niobium, tungsten, evening metal, etc., depending on the application. Elements, or compounds containing them, can be coated, supported, or doped. The method of the present invention can be carried out, for example, by immersing the seeds in water containing a visible light-responsive photocatalyst that is continuously or intermittently irradiated with light containing visible light. Alternatively, it can be carried out by immersing the seeds in water in a state where water coexists with a material containing a visible light responsive photocatalyst. The seed immersion time may be appropriately selected depending on the amount of the visible light responsive photocatalyst used or the condition and form of the seed. For example, 5 minutes to 24 hours per day (24 hours) Preferably, it can be 30 minutes to 8 hours. However, these are not limited. The temperature of the water can be appropriately determined according to the type of the seed, but is, for example, 5 to 35 ° C, preferably 10 to 20 ° C. The light to be irradiated is light containing a component having a wavelength of 420 nm or more, and preferably light containing at least a part of a component having a wavelength of 420 nm to 600 nm. For example, the light may include at least a part of a component having a wavelength of 450 nm to 600 nm. Light containing a component having a wavelength of 420 nm or more can be, for example, light from sunlight, an incandescent lamp, a light emitting diode, a halogen lamp, a fluorescent lamp, or the like. The light emitting diode is a light emitting diode having an emission wavelength in the visible light region of 420 nm or more, or having an emission wavelength only in the visible light region. Examples of such a light emitting diode include a purple light emitting diode, a blue light emitting diode, a green light emitting diode, a yellow light emitting diode, and a white light emitting diode. A violet light emitting diode has an emission wavelength from the ultraviolet region to the visible light region. Also, a blue light emitting diode, a green light emitting diode, a yellow light emitting diode, or a white light emitting diode has an emission wavelength only in the visible light region. Fig. 4 shows the emission spectra of the blue light emitting diode (BLUE), the green light emitting diode (GREEN), and the white light emitting diode (WHITE). Example

Hereinafter, the present invention will be further described with reference to examples.

Example 1

Rice germination experiment

Prepare a glass petri dish with a diameter of 10 cm covered with filter paper, and place the sample on a filter paper. 2 g was evenly applied. Water was added enough to wet the filter paper. Water was checked daily and added if it was not wet enough. The seeds used were rice (variety: Kinu Hikari). One petri dish was placed with 20 seeds spaced apart. After putting all the seeds, put the lid on the petri dish. The light source was set to be 1 cm from the sample. The light source is a blue LED (Model: NSSB450, manufactured by Nichia Chemical Industry Co., Ltd., model number NSSB450). It was lit by applying voltage so that Irradiation conditions were 2 cm for the sample from above the lid, and irradiation was performed continuously for 10 hours a day. Germination was determined when 2 mm radicles emerged from the seeds. Table 1 shows the results.

The details of each sample will be described later. table 1

ST-01 (Comparative Example): Ultrafine titanium oxide powder on the market (made by Ishihara Sangyo) Example 1: Prepared by the method described in Reference Example 3 described below.

Example 2: Prepared by the method described in Reference Example 7 below. Reference example 1

50 Og of titanium tetrachloride (Kanto Chemical Co., Ltd., special grade) was added to pure water of ice water (2 liters as water), stirred and dissolved to obtain an aqueous solution of titanium tetrachloride. About 200 ml of aqueous ammonia (containing 13 wt% as NH3) was added as quickly as possible while stirring 200 g of this aqueous solution with a mixer. The amount of added ammonia water was adjusted so that the final pH of the aqueous solution was about 8. This turned the aqueous solution into a white slurry. After further stirring for 15 minutes, the mixture was filtered with a suction filter. The precipitate collected by filtration was dispersed in 2 Om 1 ′ of aqueous ammonia (containing 6 wt% as NH 3), stirred with a stirrer for about 20 hours, and suction-filtered again to obtain a white hydrolyzate.

The obtained white hydrolyzate was transferred to a crucible and heated at 400 ° C for 1 hour in the air using an electric furnace to obtain a yellow product. The XRD measurement results of the obtained product are shown in the upper part of FIG. The lower part of Fig. 3 also shows the XRD measurement results of the white hydrolyzate dried at 50 ° C. From this result, it can be seen that the white hydrolyzate dried at 50 ° C. is amorphous, and the obtained product is ana-type titanium dioxide.

The absorption spectrum of the obtained product and the white hydrolyzate dried at 50 ° C was measured with a Hitachi automatic recording spectrophotometer (U-3210) equipped with an integrating sphere under the following conditions. scan speed: 120nm / min>

response: MEDIUM,

band pass: 2.00 turbulence

Reference: Barium sulfate

As a result, the white hydrolyzate was dried at 50 ° C, whereas the reflectance at 450 nm was 61% when the reflectance at 700 nm of the obtained product was 100%. The reflectance at 95 nm was 95% when the reflectance at 700 nm was 100%. The ESR spectrum of the obtained product was measured. The measurement was carried out in vacuum (0.1 ltorr) at 77 K or at room temperature. The measurement conditions are as follows.

[Basic parameters]

Measurement temperature 77 温度 or normal temperature

Field 324mT ± 25mT

Scan time 4 minutes

Mod. 0.lmT

Receiver 'Gain 10 ~; L 00 (Measurement sensitivity)

Time constant 0.1 second

Light source High-pressure mercury lamp 500W

Filter L-42

(Sample preparation)

Vacuum deaeration 1 hour or more (Calculation of g value)

G = g _mn XH _mn / (H _mn + AH) based on Mn ²⁺ marker (g _mn = l. 981 (third from high magnetic field side))

H _mn : magnetic field of the Mn ²⁺ marker, ΔΗ: amount of change in magnetic field from H _mn Figure 1 (measuring temperature 77 K) and Figure 2 (measuring temperature normal temperature) show the ESR spectrum in the dark, ESR spectrum measured with light irradiated through a filter (L-42) that cuts light of 420 nm or less (using a 500 W high-pressure mercury lamp) in the middle, and light of 420 nm or less in the lower. The ESR spectrum measured with a 500W high-pressure mercury lamp irradiated with light without using the filter (L-42) is shown below. Comparison of the upper and middle spectrums in Fig. 1 clearly shows that in the middle spectrum, the main signal with a g value of 2.004 to 2.007 and a g value of 1.985-1 The two side signals, 986 and 2.024, were more intense than in the upper spectrum. Also, comparing the spectra in the middle and lower rows of Fig. 1, it is clear that the g-value power is S2.004 to 2.007, the main signal, and the g-value is 1.985 to 1.986 and 2.024. The intensities of the two sub-signals were not substantially different even when the irradiation light contained light of 420 nm or less. Further, as shown in FIG. 2, the visible light responsive material of Reference Example 1 has the three signals measured in the air, at room temperature, in the dark, and in ESR under light irradiation having a wavelength of 420 nm or more. Met. In addition, when the white hydrolyzate was dried at 50, the main signal having a g value of 2.004 to 2.007, and the g value of 1.985 to; I. 986 and 2.024 Two side signals were not observed under any of the ESR measurement conditions. Reference example 2

3 g of the powder obtained in Reference Example 1 was suspended in 100 ml of pure water, and stirred for 1 hour using a magnetic stirrer. The obtained solution was subjected to suction filtration. The sample remaining on the filter paper was again stirred in pure water, and suction filtration was performed. Filtration was repeated three times until the filtrate reached pH 6 to pH filter paper.

The obtained powder was left in a dryer set at 110 ° C. for a day and a night, and dried to obtain a visible light responsive material. Reference example 3

23 kg of titanium tetrachloride was gradually added to 207 kg of water at a temperature of 0 ° C. filled in a 300-liter reaction vessel (which can be cooled and stirred). At this time, the temperature of the aqueous solution was up to 6 ° C. Titanium chloride was stirred for 2 days to produce a transparent titanium tetrachloride aqueous solution. When the prepared aqueous titanium tetrachloride solution was stirred and 12.5% aqueous ammonia was added dropwise, the solution became cloudy gradually. The amount of aqueous ammonia was adjusted so that the cloudy solution became pH 8.

The cloudy solution was subjected to suction filtration. The amount of white precipitate remaining on the filter paper was 131 kg. The white precipitate was dispersed in 200 kg of aqueous ammonia (6% as N¾), stirred for 24 hours, and subjected to suction filtration. After filtration, a white precipitate It was 108 kg. The white precipitate was dried for 4 days in a forced-air shelf dryer set at 50 50. After drying, the sample weighed 17 kg.

Place the dried sample in an alumina crucible (20 X 20 X 5 cm) I kg, place it in a gas furnace, place a thermocouple on the sample surface, and set the sample temperature to 400 ° C for 1 hour Fired.

3 g of the prepared powder was suspended in 10 Oml of pure water and stirred for 1 hour using a magnetic mixer. The obtained solution was subjected to suction filtration. The sample remaining on the filter paper was again stirred in pure water and subjected to suction filtration. Filtration was repeated three times until the filtrate reached 6 to 7 with pH test paper.

The obtained powder was left in a dryer set at 110 ° C. for a day and a night, and dried to obtain a visible light responsive material. Reference Example 4 (Method of manufacturing visible light responsive material from titanium sulfate (1))

Titanium sulfate (IV) solution as titanium sulfate (IV) solution (Trade name: Kanto Chemical Co., Ltd .: Titanium sulfate (IV) (deer grade 1, water-soluble night containing titanium sulfate (IV) at 24% by weight or more)) The stock solution of was used as it was. While stirring 50 g of this aqueous solution with a stirrer and adding 58 ml of aqueous ammonia (ammonia stock solution: water = 1: 1) as quickly as possible with a burette, stirring was continued. Was. Further, ammonia water was added, and the pH was adjusted to 7 with a universal test strip. After 24 hours, the mixture was filtered with a suction filter. The white matter attached to the filter paper was washed in ammonia water adjusted to pH 11 and filtered again eight times, and washed to obtain a white powder. The obtained powder was dried at 50 ° C to obtain a sample powder. The BET surface area of the obtained hydrolyzate (sample powder) was 308.7 m ² Zg. Obtained 8 g of the sample powder placed in the crucible was transferred to an electric furnace and baked at 400 ° C. for 60 minutes to obtain 6.3 g of a bright yellow powder having a BET surface area of 89.4 m ² / g. An X-ray diffraction (XRD) test of this powder shows that it contains anabsorbate-type titanium oxide. Furthermore, as a result of an X-ray photoelectron spectroscopy (XPS) test measured with an X-ray photoelectron spectrometer (trade name: Quarturn 2000, manufactured by ULVAC-FAI Co., Ltd.), the peak attributed to the 2p electron of titanium obtained was obtained. The abundance ratio (O / T i) between the oxygen element and the titanium element calculated from the area of the peak and the area of the peak attributed to the 1 s electron of oxygen indicates that the crystal structure of the powder has oxygen deficiency. showed that. Due to this oxygen deficiency, Powder A is colored bright or pale yellow, and is considered to have visible light activity (photocatalytic activity).

The ESR spectrum of the obtained powder was measured. The measurement was performed at 77 K in a vacuum (0.1 Torr). The measurement conditions are the same as in Reference Example 1.

Fig. 5 (measuring temperature 77Κ) shows the ESR spectrum measured with light irradiated through a filter (L-42) that cuts light below 420 nm (using a 500 W high-pressure mercury lamp). In addition, the ESR spectrum under the black bottom was also measured, but no signal was practically observed. In the spectrum shown in FIG. 5, a main signal having a g-value of 2.004 to 2.007 and two sub-signals having g-values of 1.985 to 1.986 and 2.024 were observed.

Incidentally, when the white hydrolyzate was dried at 50, the main signal having a g-value of 2.004-2.007 and the g-values of 1.985 to 1.986 and 2.024 2 One side signal was not observed under any of the ESR measurement conditions and Was. Reference Example 5 (Production method of visible light responsive material from titanium sulfate (2))

Add 50 g of a 24% titanium sulfate solution (Kanto Kagaku, Shika grade) to 400 mL of distilled water, and stir with a magnetic stirrer. There, concentrated ammonia water (28%, Kanto Chemical, special grade) is added to perform neutralization reaction. After the neutralization reaction, adjust the pH to 7 and stir for 15 minutes. At this time, add distilled water (200 mL) because the stirrer may not rotate. After 15 minutes, stop stirring and let stand for a while. Discard the supernatant. Filtration is performed by Nutsche, and at this time, it is washed with 2 L of aqueous ammonia (5:95). This is a method of adding ammonia water when it becomes a cake on filter paper. Thereafter, the obtained product was dried at 60 ° C for 24 hours, and calcined at 400 ° C for 1 hour to obtain a visible light responsive material of the present invention. The NO oxidation activity of the obtained material was measured by the following test examples, and is shown in Table 2. Test example (N Ox removal activity)

Samples applied to 0.2 g glass plates (6 x 6 cm) were placed in a Pyrex glass reaction vessel (inner diameter 160 mm, thickness 25 mm). Light was emitted as a single light color with a half-value width of 20 nm using an irradiator using a 300 W xenon lamp (trade name: SM-5 type CT-10, manufactured by JASCO Corporation).

Simulated contaminated air (NO: 1111) with a humidity of 〇% RH was continuously supplied to the reaction vessel at a flow rate of 1.5 liters Z, and the change in the concentration of NO and NO ₂ at the reaction outlet was monitored. The NO concentration was measured by a chemiluminescence method using ozone. Removal rate of the NO X at each measurement wavelength from the accumulated value of the monitor value of one hour a (%) (= NO reduction rate one N0 ₂ generation rate) were obtained. For measurement of NO concentration, Monitor labs Inc. Nitrogen Oxides analyzer Model 8840 was used. Table 2

The ESR spectrum of the obtained material was measured. The measurement was performed at 77 K in a vacuum (0.1 l rr). The measurement conditions are the same as in Reference Example 1.

Figure 6 (measurement temperature 77K) shows the ESR spectrum measured with light irradiated through a filter (L-42) that cuts light below 420 nm (using a 500W high-pressure mercury lamp). In the spectrum shown in FIG. 6, a main signal having a g value of 2.004 to 2.007, and two sub-signals having g values of 1.985 to 1.986 and 2.024 were observed.

In addition, when the white hydrolyzate was dried at 50 ° C, the main signal having a g value of 2.004 to 2.007, and the g value of 1.985 to 1.986 and 2.024 The two side signals were not observed under any of the ESR measurement conditions. Reference Example 6 (Production method from alkoxide)

While stirring to 200 g of pure water, 30 g of titanium isopropoxide was gradually added (molar ratio of water to titanium isopropoxide = about 10: 1). After the obtained solution was stirred for about 30 minutes, the precipitate (hydrolyzate) was collected by filtration. The precipitate (hydrolyzate) was suspended in pure water and stirred for 1 day. It was dried at 10 ° C and calcined at 400 ° C for 1 hour. The obtained white powder is used as Sample A.

Instead of suspending the precipitate (hydrolyzate) in pure water and stirring for 1 day, the precipitate (hydrolyzate) was suspended in ammonia water (concentration of ammonia: 6%) and stirred for 1 day. The yellow powder is used as Sample B in the same manner as above, except that it was used.

The NO activities of Samples A and B were measured in the same manner as in the above test method. The results are shown in Table 3 below. '

Table 3

NO activity

Sample A

Sample B

From the results shown in Table 3, it can be seen that a material composed of titanium oxide having visible light response can be obtained by heat-treating titanium oxide (hydrolyzate of titanium) in the presence of ammonia. The ESR spectrum of the obtained material was measured. The measurement was performed at 77 K in a vacuum (0.1 Torr). The measurement conditions are the same as in Reference Example 1. Figure 7 (measurement temperature 77K) shows the ESR spectrum measured with the light irradiated through a filter (L-42) that cuts light below 420 nm (using a 500 W high-pressure mercury lamp). In the spectrum shown in FIG. 7, a main signal having a g value of 2.004 to 2.007, and two sub-signals having g values of 1.985 to 1.986 and 2.024 were observed.

When the white hydrolyzate was dried at 50 ° C, the main signal with a g value of 2.004 to 2.007 and the g value of 1.985 to 1.986 and 2.024 One of the two side signals was not observed under any of the ESR measurement conditions. Reference Example 7 (plasma method)

5 g of anatase type titanium dioxide powder (ST-01, manufactured by Ishihara Sangyo Co., Ltd.) was placed in a quartz reaction tube having an inner diameter of 5 cm and a length of 100 cm. An RF plasma generator was attached to this quartz reaction tube, and the inside of the reaction tube system was evacuated to 0.1 Torr by a vacuum pump. Then, 500 W of electromagnetic waves (13.56 MHz) were introduced into the reaction tube. The plasma was generated by irradiating the titanium oxide powder. Then, H ₂ gas (flow rate of 500 ml Z) was introduced so that the pressure in the system was about 1 Torr. The anatase type titanium dioxide powder in the reaction tube was treated for 30 minutes while stirring. The quartz tube wall was heated to 400 ° C by resistance heating with a nichrome wire, and the temperature was maintained during the reaction. The obtained anatase-type titanium dioxide powder was subjected to X-ray photoelectron spectroscopy (XPS) to determine the peak (458.8 eV (T i 2 p 3/2)) 464.6 e V (T i 2 p 1/2) area and peak (531.7 e V (O ls) area) attributed to the 1 s electron of oxygen bonded to titanium The obtained area ratio (O 1 s / T i 2 p) was 1.94, and the area ratio (O 1 s / T i 2 p) of the anatase-type titanium dioxide powder not subjected to the plasma treatment. Was 2.00.

The area ratio (O 1 s / Ti 2 p) measured in the same manner as above after leaving this sample in the air for one week was 1.94. Furthermore, there was no change in the area ratio (〇 1 sZT i 2 p) of this sample after one month. In addition, as a result of subjecting the sample before the plasma treatment and the sample after the treatment to an X-ray diffraction test, no change was observed in the ana-type titanium dioxide before and after the plasma treatment.

The ESR spectra of the sample before the plasma treatment and the sample after the treatment were measured. The measurement was performed at 77 K in a vacuum (0.1 Torr). The measurement conditions are as follows.

[Basic parameters]

Measurement temperature 77 K

Field 330mT ± 25mT

Scan time 4 minutes

Mod. 0.lmT

Gain 5X 10

Power 0.lmW Time constant 0.0 3 seconds

Light source High-pressure mercury lamp 500 W

Filter L-4 2

(Sample preparation)

Vacuum deaeration 1 hour or more

(Calculation of g value)

Based on Mn ²⁺ marker one (g _mn = l. 9 8 1)

g = g _mn XH _mn / (H _mn + AH)

H _mn : magnetic field of the Mn ²⁺ marker, ΔΗ: change in magnetic field from H _mn Figure 8 shows the ESR spectrum of the sample before plasma treatment. In the figure, (a) is the ESR spectrum under black and (b) is the light passing through a filter (L-42) that cuts light below 420 nm (using a 500 W high-pressure mercury lamp). This is the ESR spectrum measured in the irradiated state.

Figure 9 shows the ESR spectrum of the sample after the plasma treatment. In the figure, (a) is the ESR spectrum in the dark, and (b) is the light passing through a filter (L-42) that cuts light below 420 nm (using a high-pressure mercury lamp of 500 W). The ESR spectrum measured in the illuminated state, and (c) is the ESR spectrum measured in the illuminated state without passing through the filter (L-42).

The ESR spectra shown in FIGS. 8 and 9 were measured under the same conditions.

Comparing the two, the catalyst obtained above has a signal specific to g = 2.03-4, which is not found in the starting material, and the signal is less than 420 nm. It is amplified under the light irradiation that cut The catalyst obtained above (plasma treatment In the anatase-type titanium dioxide), a signal was observed at a g value of 2.03 to 4 at which the intensity increased with visible light of 420 nm or more. In addition, the peak of this bracket was maintained when the sample was left in the air for one week and measured again. Further, in the catalyst obtained above, no signal attributed to ^{Ti 3+} showing a signal with a g value of 1.96 was not observed. Industrial applications

In the method of the present invention, the seeds are germinated by immersing the seeds in water containing a visible light responsive photocatalyst or a material containing the visible light responsive photocatalyst, which is continuously or intermittently irradiated with light containing visible light. And the germination rate is improved, and at the same time, the seeds are also killed. Therefore, according to the method of the present invention, the total cost in the seed germination step can be reduced.

Claims

■ Scope of request

1. A photocatalyst that is activated by the action of light having a wavelength of 420 nm or more (hereinafter referred to as a visible light responsive photocatalyst) or a seed that is coexistent with water and a material containing the visible light responsive photocatalyst, A method for promoting seed germination, comprising continuously or intermittently irradiating light including visible light.

2. The method according to claim 1, wherein the material containing a visible light responsive photocatalyst is an organic coating film, an inorganic coating film, or a fiber.

3.The visible light-responsive photocatalyst is titanium oxide containing at least anatase-type titanium oxide, and the ESR measured under the irradiation of light having a wavelength of 420 nm or more at 77 K in a vacuum is as follows: A main signal with a g-value of 2.00 to 2.007 and two sub-signals with a g-value of 1.985 to 1.986 and 2.024 were observed. The method according to claim 1, wherein the three signals are visible light responsive materials that are minutely observed or substantially not observed in vacuum at 77 K in the dark.

4. The method according to claim 1, wherein the visible light responsive photocatalyst is a visible photocatalyst comprising titanium dioxide having a stable oxygen vacancy.

5. The method according to any one of claims 1 to 4, wherein the light containing visible light is light of a light emitting diode.

6. The method according to claim 5, wherein the light emitting diode is a violet light emitting diode, a blue light emitting diode, a green light emitting diode, a yellow light emitting diode, or a white light emitting diode.