KR20030012956A - Method for killing of microorganisms in the water by UV-TiO2 photocatalytic reaction and reactor for killing of microorganisms - Google Patents

Abstract

PURPOSE: A sterilization method of water by UV/TiO2 photocatalytic reaction and a unit therefor are provided, which can enhance sterilizing effect and shorten sterilizing time. The reactor is also easy to clean by easily dismantling it thus keeping high sterilizing efficiency all the time. CONSTITUTION: The sterilization unit comprises a service water storage tank(20), a photocatalyst reactor(10), an influent pump(22), an air pump(31) and a sterilized water storage tank(51). The sterilization method comprises the steps of feeding service water containing dissolved hydrogen peroxide at a rate of 25 to 50 mg/L to the photocatalyst reactor(10) filled with porous media(11) wherein the muscovite media with a diameter of 6 to 10 mm is coated with titanium dioxide; irradiating ultraviolet ray while feeding air through an influent pipe(30) simultaneously.

Description

Method and apparatus for sterilizing water by photocatalytic reaction {Method for killing of microorganisms in the water by UV-TiO2 photocatalytic reaction and reactor for killing of microorganisms}

The present invention relates to a method and apparatus for sterilizing water by a photocatalytic reaction, and more particularly, to a porous catalyst coated with a photocatalyst inside a photocatalytic reactor, to inject air, and to irradiate ultraviolet rays to irradiate ultraviolet rays, thereby adding water to hydrogen peroxide. It relates to a method and apparatus for sterilizing or decomposing microorganisms and organic substances contained in the water by injection by photocatalytic reaction.

With the recent decline in rainfall in Korea, the lack of drinking water as well as agricultural water has emerged as a serious problem. Most farmers use traditional, inefficient irrigation systems, and modern trickle irrigation supplies water where it is needed efficiently and efficiently, but water shortages are not easily resolved because of the large amounts of money required. Therefore, in order to solve the shortage of water in the cultivation of crops, it is inevitable to recycle the water, and it is necessary to recycle the water for the continuous use of seawater or fresh water used in large aquariums. For the use of recycled water, the most important thing is the sterilization of microorganisms in the recycled water.

In Korea, chlorine sterilization is mainly used as a control means for bacteria, viruses, and algae, but recently, problems such as trihalomethane (THM) generation caused by chlorine sterilization and residualness when used as pure water or ultrapure water It is happening. In addition, the high water purification process using ozone has a problem that requires a lot of facility investment and maintenance costs, and recently, a method of sterilization using TiO ₂ as a photocatalyst has emerged as a method for low-cost facility investment and easy maintenance.

The sterilization method using TiO ₂ is based on a reaction mechanism according to the following reaction formula.

According to Scheme 1, electrons and holes are generated by absorbing energy above the band-gap energy due to ultraviolet rays from TiO ₂ , and the generated e ^- _CB and h ⁺ _VB are TiO _2. Diffuse and move on the surface.

Diffused h ⁺ _VB is OH in the water according to the reaction schemes 2 ^- generate OH · reacts with, and by addition reaction with water molecules and sikigido generate OH · and H ^+, and sikigido directly oxidize the organic material and the reaction and the organic .

In addition, e ^- _CB is the water react with oxygen to superoxide radicals ^{_{(superoxide radical, O 2 - ·}} ) according to the scheme 3 is created and, again, O ₂ ^- · has to react with the water molecule with two OH · and two OH ^In addition, it forms a molecule of oxygen, and when hydrogen peroxide is added, hydrogen peroxide reacts with UV to produce 2OH, or hydrogen peroxide reacts with e ^- _CB or dissolved oxygen to produce OH. Therefore, OH · thus produced is related to the oxidation of organic matter.

Photocatalytic disinfection method using a TiO ₂ to carry out the reaction mechanism when using the TiO ₂ in powder form takes the energy for injury material the photocatalyst particles in the during continuous processing of the contaminants the aqueous solution, have to recover the photocatalyst in the subsequent processing step There is a problem. When coating TiO ₂ directly on UV lamps, the problem of disposal when the lamp reaches the end of life and the coating on the inner wall of the reactor are very difficult to coat when the reactor is large. Because of this, there is a problem that indicates the limit in the material of the device. In addition, there is a problem in that the desorption rate of TiO ₂ increases when coated on a normal bead.

In order to solve the above problems, the present inventors fill a photocatalyst-coated porous carrier inside the photocatalytic reactor, inject air, and irradiate ultraviolet rays to inject water containing hydrogen peroxide to contain the water in the water by the photocatalytic reaction. As a result of researching devices and sterilization methods for sterilizing microorganisms and organic matters, the sterilization time can be shortened, and the sterilization effect can be increased by adding air and hydrogen peroxide during sterilization, and it can be manufactured in a small place. The present invention was completed by finding a sterilization apparatus and a sterilization method capable of separating the photocatalytic reactor and the easy cleaning of the apparatus.

An object of the present invention is to provide a water sterilization apparatus having a photocatalyst reactor filled with a photocatalytic coated porous carrier, an ultraviolet lamp for irradiating ultraviolet rays, and an air inlet pipe for injecting air into the photocatalytic reactor.

Further, another object of the present invention is to provide a sterilization method for effectively sterilizing microorganisms in water using the water sterilization apparatus.

1 is a cross-sectional view showing a preferred example of the water sterilization apparatus of the present invention

2 is a side view showing a photocatalytic reactor of the present invention

3 is a view showing a water sterilization apparatus prepared in parallel with the photocatalytic reactor of the present invention

Figure 4 is a photograph of the porous carrier coated with TiO ₂ of the present invention

5 is a graph comparing the sterilization effect (a) and the sterilization efficiency (b) comparing the coating of TiO ₂ on the glass beads with the coating on the porous carrier of the present invention.

Figure 6 is a graph showing the sterilization effect (a) and sterilization efficiency (b) for E. coli per each ultraviolet lamp according to the diameter of the photocatalytic reactor of the present invention

Figure 7 is a graph showing the sterilization effect (a) and sterilization efficiency (b) for E. coli when the air is injected into the photocatalytic reactor of the present invention

8 is a graph showing the bactericidal effect on E. coli according to the concentration of hydrogen peroxide during the photocatalytic reaction of the present invention

9 is a graph showing the sterilization efficiency against E. coli when only hydrogen peroxide was added without causing a photocatalytic reaction.

10 is a graph showing the effect on the growth of bean sprouts according to the concentration of hydrogen peroxide of the present invention

11 is a graph showing the sterilization effect (a) and the sterilization efficiency (b) for E. coli when the amount of treated water doubled during the photocatalytic reaction of the present invention.

12 is a graph showing the bactericidal effect (a) and sterilization efficiency (b) for the bacteria present in the sprouts of the present invention

Figure 13 is a graph showing the bactericidal effect (a) and sterilization efficiency (b) for the fungi present in soybean sprouted water of the present invention

* Description of the symbols for the main parts of the drawings *

100: water sterilization apparatus 10: photocatalytic reactor

11: Photocatalytic Coated Porous Carrier

12: UV lamp 13: outlet

14: inlet port 15: inner frame

16: outer frame 17: O-ring

18: connection 20: water reservoir

21: water feed pipe 22: inlet pump

30: air inlet pipe 31: air pump

40: UV stabilizer 41: electric wire

50: photocatalytic filtration network 51: sterile water reservoir

In order to achieve the above object,

The present invention provides a device for sterilizing water by a photocatalytic reaction through a photocatalytic reactor,

A water reservoir for storing water,

A photocatalytic reactor comprising an inlet, an outlet, and a porous carrier coated with a photocatalyst therein, an ultraviolet lamp, and an air inlet tube,

An inlet pump located between the water reservoir and the photocatalytic reactor,

An air pump that introduces air into the air inlet pipe and

It relates to a water sterilization device consisting of a sterilized water reservoir for storing the sterilized water through the photocatalytic reactor.

In addition, the present invention provides a sterilization method for removing microorganisms contained in the water by irradiating UV light while injecting air with hydrogen peroxide added to the photocatalytic reactor by using the above water sterilization device.

Hereinafter, a water sterilization apparatus of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing a preferred example of the water sterilization apparatus 100 of the present invention.

As shown in Figure 1 , the water sterilization apparatus 100 of the present invention, in order to sterilize the water by the photocatalytic reaction,

The photocatalytic reactor 10 causing the photocatalytic reaction is filled with a porous carrier 11 coated with a photocatalyst therein,

The ultraviolet lamp 12 is installed in the horizontal direction inside the photocatalytic reactor, but when viewed from the side of the photocatalytic reactor 10 is mounted inside the photocatalytic reactor 10 at regular intervals in the form of crosses irradiated from the ultraviolet lamp 12 Ultraviolet rays react with the photocatalytic coated porous carrier 11 to generate OH ·, a powerful oxidant,

In order to inject air into the photocatalytic reactor, an air inlet pipe 30 through which the air is introduced into the reactor from the air pump 31 is mounted in the horizontal direction at the bottom of the photocatalytic reactor 10,

The inlet 14 and the outlet 15 of the water are respectively installed at the upper and lower ends of the photocatalytic reactor 10, and are installed in a diagonal direction to increase the residence time in the photocatalytic reactor 10,

The photocatalyst filter network 50 is installed to prevent the photocatalytic coated porous carrier 11 from flowing out of the photocatalytic reactor 10 at the inlet 14 and the outlet 13 of the photocatalytic reactor 10,

A rubber O-ring 17 is sandwiched and packed between the inner and outer frames 15 and 16 of the reactor, and the sealed portion is sealed using the connection part 18.

In this case, the inner and outer frames 15 and 16 of the photocatalytic reactor 10 of the present invention are made of transparent acrylic, and thus the inside of the photocatalytic reactor 10 can be easily observed, and there is an abnormality of the ultraviolet lamp 12. And the replacement time can be easily checked with the naked eye.

Specifically, as shown in FIG . 4 , the photocatalyst-coated porous carrier 11 is prepared by first baking white mica having a high porosity at 800 ° C., then coating the surface with a photocatalyst and then heat-treating again at 1400 ° C. FIG. TiO ₂ is used as the photocatalyst, and the photocatalyst coated porous carrier 11 can effectively sterilize or decompose microorganisms and organic substances contained in water by increasing the surface area. The diameter of the carrier is preferably 6 to 10 mm, and if the carrier is less than the above range, the carrier is too dense and there is a problem in water flow rate. If the carrier exceeds the above range, the sterilization efficiency tends to decrease as the total surface area of the carrier decreases. Indicates.

In particular, the porous carrier is coated with a photocatalyst to irradiate ultraviolet rays to act as a catalyst in the water sterilization process. The photocatalyst coated porous carrier 11 can be used semi-permanently because it can be reused by simply heat treating microorganisms and organic substances attached to the pores of the carrier after several uses.

The photocatalyst coated porous carrier 11 filled in the photocatalytic reactor of the present invention has several advantages over glass beads coated with a conventional photocatalyst. Although the adsorption capacity of microorganisms and organic materials is excellent due to the porosity, the surface area is increased, and the sterilization efficiency is increased, and the photocatalyst coated glass beads have a short lifetime since the photocatalyst is easily desorbed over time. It can be called semi-permanent. Specifically, as a result of sterilizing the water using the photocatalyst coated glass beads and the porous carrier in the photocatalytic reactor of the sterilization apparatus of the present invention, as shown in FIG. 5 , the TiO ₂ coated porous carrier 11 was used. The bactericidal effect and sterilization efficiency against E. coli were found to be more excellent.

The ultraviolet lamp 12 for ultraviolet irradiation is mounted while maintaining a predetermined interval inside the photocatalytic reactor, the distance between the ultraviolet lamps 12 affects the sterilization effect of the water. Since the ultraviolet lamp 12 induces the formation of a strong oxidizing agent OH · generated by irradiating the photocatalyst coated porous carrier 11, the ultraviolet lamp 12 is installed so that ultraviolet light is irradiated on all the filled photocatalyst coated porous carrier 11. The distance between the ultraviolet lamps 12 can be adjusted and modified according to the size of the photocatalytic reactor 10. In the present invention, using a photocatalytic reactor 10 having a diameter of 20 cm and a length of 72 cm, the ultraviolet lamps 12 are arranged at regular intervals and then irradiated with ultraviolet rays to measure sterilization efficiency. When it is -80 mm, the preferable effect was shown. Since the above result is only an example, when the water of a large capacity is to be treated, the distance of the ultraviolet lamp 12 mounted as the size of the photocatalytic reactor 10 is increased may be adjusted.

Compared with the conventional method of installing a quartz tube outside the ultraviolet lamp 12 to protect the electrode of the ultraviolet lamp 12 in water, it is effective in various ways. In addition, since the electrode portion protrudes out of the photocatalytic reactor 10 to completely seal the photocatalytic reactor 10, the ultraviolet lamp 12 can be installed without using a quartz tube, and the material cost can be reduced. In particular, since the inner and outer frames 15 and 16 are designed so that the inside can be seen using transparent acrylic, it is possible to visually recognize the abnormality and replacement time of the ultraviolet lamp 12, and the inner and outer frames (15 and 16). Since the airtightness of the photocatalytic reactor 10 was maintained at the edges of the photocatalyst reactor 10, the ultraviolet lamp 12 could be easily replaced by dismantling only the connection 18. The connecting portion 18 may use a bolt and nut or a connecting portion 18 that is typically removable.

The air inlet pipe 30 is positioned at the bottom of the photocatalytic reactor 10 and mounted to inject air into the photocatalytic reactor 10. The air inlet pipe 30 is perforated at a very fine interval so as not to be blocked by the photocatalytic coated porous carrier 11, and at this time, an air pump equipped with an air pump 31 or a regulator to control air pressure (31) is used. Air flowing from the air pump 31 increases sterilization efficiency by increasing dissolved oxygen in the water, and a large amount of air inflow creates turbulent flow of water in the photocatalytic reactor 10 to increase the reaction efficiency. It is efficient to use the pump 31.

The photocatalytic filter network 50 is configured to prevent the photocatalytic coated porous carrier 11 filled in the photocatalytic reactor 10 from flowing into the water transfer pipe 21. 15) respectively. The size of the photocatalyst filter net 50 is controlled according to the size of the porous carrier, it is made of a plastic material.

In addition, the water sterilization apparatus 100 of the present invention is for controlling the on and off of the water transfer pipe 21 and the ultraviolet lamp 12 for injecting the water in the water reservoir 20 into the photocatalytic reactor 10. Ultraviolet ballast 40 is included.

As described above, the water sterilization apparatus 100 of the present invention includes a photocatalyst coated porous carrier 11, an ultraviolet lamp 12, and an air inlet tube 30. In particular, the water sterilizing apparatus 100 of the present invention are produced by large, or can be disposed by making in parallel with small as shown in Fig. 3 in order to handle large volumes of water, such production is the conventional knowledge in the art It can be transformed by the person who owns it, and can be used for recycling after sterilization of all water, such as agricultural water, saltwater or fresh water of aquarium.

In addition, the present invention includes a sterilization method using the sterilization apparatus 100 of the water.

In the method of sterilizing water by photocatalytic reaction,

Add hydrogen peroxide to the water,

Injected into the photocatalytic reactor 10 is filled with a photocatalyst coated porous carrier 11,

While injecting air into the air inlet pipe 30 and irradiating ultraviolet rays,

It is a method for sterilizing microorganisms in water by photocatalytic reaction of photocatalyst and water coated on the porous carrier.

The flow of water circulates from the water reservoir 20 to the top outlet 13 from the bottom inlet 14 of the photocatalytic reactor 10 using the inlet pump 22, wherein the water in the photocatalytic reactor 10 is photocatalyst coated. Ultraviolet rays are irradiated to the porous carrier 11 to be sterilized by OH. Generated at this time, and stored in the sterilized water reservoir 51 after sterilization.

In addition, in order to increase the sterilization effect, a small amount of hydrogen peroxide was added to the water reservoir 20 when the sterilization device was operated so that water containing hydrogen peroxide was introduced into the photocatalytic reactor 10 to obtain a high sterilization effect. The amount of can be adjusted according to the amount of water, the preferred concentration of hydrogen peroxide is 25 ~ 50 mg / L, the use of a minimum amount is important because there is a possibility of economic and stability problems when treating high concentration of hydrogen peroxide. As shown in Figure 8 it can be seen that the sterilization time is shortened and the sterilization effect is increased as the amount is increased when the low concentration of hydrogen peroxide is treated.

As a result of comparative experiments using only hydrogen peroxide without ultraviolet rays in FIG. 9 , it can be seen that bacteria are not simply sterilized by hydrogen peroxide, but exhibit high sterilization effect when hydrogen peroxide is added together with ultraviolet irradiation.

By increasing the dissolved oxygen in the water from the air pump 31 through the air inlet pipe 30 to obtain a higher sterilization effect, which forms turbulence of the water, and the OH · and the water generated from the mixing of the water and pollutants and photocatalysts It serves to increase the contact. In the present invention, the amount of air injected into the photocatalytic reactor 10 was 30 L / min, and it is preferable to use an air pump as powerful as possible without limiting the reactor.

In comparison with the case where no air is injected using the water sterilization apparatus 100 according to FIG. 7 , when the air is injected, the sterilization effect is higher at the initial stage of the reaction. According to the following examples, when no air was injected, it showed 90.6% sterilization effect for 1 minute, and when air was injected, it showed a higher sterilizing effect at the beginning of the reaction with 95% of sterilization effect. This is because the air injected during the photocatalytic reaction causes turbulence in the reactor and increases the dissolved oxygen so that the OH.

Safety problems according to the use of the hydrogen peroxide of the present invention can be confirmed through Table 1 and FIG . Table 1 shows the effect of the concentration of hydrogen peroxide on the germination rate of bean sprouts.

unit(%) H ₂ O ₂ concentration (mg / L) Day 0 10 50 100 500 1000 One 71.67 20.00 53.33 60.00 78.33 50.00 2 90.00 86.67 76.67 86.67 93.33 95.00 3 91.67 88.33 80.00 88.33 93.33 95.00

According to Table 1 , the germination rate was slightly reduced at the concentration of hydrogen peroxide 50 mg / L, but then recovered again, according to Figure 10 the total length of the bean sprouts according to the concentration of hydrogen peroxide tended to increase by the hydrogen peroxide 500 mg / In L, there was a statistically significant difference (at 5% significance level), and the axial length was not significantly different between 100 mg / L and no hydrogen peroxide, but significantly increased at 500 mg / L. It was. Soybean sprout root length tended to increase by hydrogen peroxide, and the axis thickness was not different from that without treatment with hydrogen peroxide. Therefore, the safety of the use of hydrogen peroxide can be seen that there is no problem.

In addition, when sterilizing by increasing the amount of water doubled using the photocatalytic reactor 10 of the photocatalytic reactor 10 of the present invention, as shown in FIG. In consideration of the fact that the amount of water treated has doubled, it can be seen that a similar result is obtained within a short time, thereby showing a very high sterilization effect. And, if you want to sterilize the water with a large capacity, several photocatalytic reactors 10 can be produced in parallel to treat the water.

An embodiment of the present invention will be described below.

However, it is not limited by the embodiment of the present invention.

Example 1 Sterilization Method of Water by Photocatalytic Reaction

As a result of manufacturing various types of reactors and establishing optimum conditions for sterilization, a photocatalytic reactor 10 having a length of 720 mm and a diameter of 200 mm was used, and a porous carrier 11 coated with TiO ₂ having a diameter of 8 mm was used. The concentration of hydrogen peroxide added was adjusted to 0 to 75 mg / L, the amount of air injected through the air inlet tube 30 was 30 L / min, and the ultraviolet lamp 12 emits up to 39 W at 254 nm. The water was sterilized under conditions using an ultraviolet lamp 12 which emits light. In the embodiment of the present invention, the bactericidal effect was measured by diluting the fraction by a continuous dilution method when the reactor was operated, and then incubating by diluting 100 μl of the dilution water onto the growth solid medium of bacteria and fungi. The number of colonies shown in the culture dish was counted and confirmed.

Experimental Example 1 Sterilization of Escherichia Coli for Each UV Lamp According to Reactor Diameter

In order to determine the optimal sterilization range for each UV lamp, the sterilization effect on E. coli of the photocatalytic reactor 10 of 55, 80, and 110 mm in diameter in which one UV lamp 12 was installed was examined.

In each photocatalytic reactor 10, a carrier coated with TiO ₂ was coated, and a buffer solution containing Escherichia coli was circulated in the photocatalytic reactor 10, and UV light was irradiated for 15 minutes to observe the bactericidal effect of E. coli. The results are shown in Table 2 and FIG. 6 .

Sterilization Effect (cell / mL) 0 min 1 minute 15 mins 55 mm 7.1 × 10 ³ 375 13 80 mm 7.3 × 10 ³ 823 21 110 mm 7.1 × 10 ³ 3.1 × 10 ³ 201

remindTABLE 2And6Depending on the, If the diameter of the photocatalytic reactor 10 is 55 mm, 7.1 × 10 for 1 minute³It showed 95% sterilization effect from cell / ml to 375 cell /. After 15 minutes, 13 cells / ml remained and 99.8% of sterilization, and 7.3 × 10 for 80 mm.³It showed 88.6% sterilization effect from cell / ml to 829 cell / ml, and after 15 minutes, it showed 99.7% sterilization effect at 21 cell / ml. Was observed. But for 110 mm, 7.1 × 10 for 1 minute³3.1 × 10 in cell / ml³The cell / ml showed 57.5% sterilization effect, and after 15 minutes, 201 cells / ml remained and 97.2% showed less sterilization effect than 55mm and 80mm reactors. Therefore, in the sterilization effect of the 55 mm and 80 mm reactors, the sterilization effect of the 80 mm reactor was slightly decreased for 1 minute, but afterwards, the sterilization effect was similar. Since the sterilization effect is achieved, the size of the reactor for each ultraviolet lamp 12 is most appropriately between 55 and 80 mm.

Experimental Example 2 Sterilization of Escherichia Coli When Air is Injected into the Photocatalytic Reactor

30 L / min air was injected into the ultraviolet photocatalytic reactor 10 of the present invention through the air inlet tube 30 using the air pump 31, and the sterilizing effect on E. coli was observed for 15 minutes. When no air was injected, it was compared with the bactericidal effect on E. coli. In this case, the measurement results are shown in Table 3 and FIG. 7 .

Sterilization Effect (cell / mL) 0 min 1 minute 15 mins If no air is injected 7.1 × 10 ³ 668 70 If air is injected 7.1 × 10 ³ 357 13

According to Table 3 and FIG. 7 , when the air was not injected, the bactericidal effect was 90.6% from 7.1 × 10 ³ cells / ml to 668 cells / ml for 1 minute, and after 15 minutes, 70 cells / ml of individuals Survived. The sterilization effect when air was injected for the same time showed 95% sterilization effect from 7.1 × 10 ³ cell / ml to 357 cell / ml after 1 minute, and after 15 minutes only 13 cells / ml survived. Thus, when air was injected, it showed a higher sterilizing effect at the beginning of the reaction than otherwise. This is because the air injected during the photocatalytic reaction causes turbulence in the photocatalytic reactor 10 to allow OH.sub.2 to react with organics more effectively and increase the dissolved oxygen to increase the production of OH.

Experimental Example 3 Sterilization of Escherichia Coli When Hydrogen Peroxide was Added during Photocatalytic Reaction

Into the photocatalytic reactor 10 of the present invention, 30 L / min of air was injected into the reactor using an air pump 31 while adjusting the hydrogen peroxide concentration to 10, 15, 20 and 25 mg / L. The bactericidal effect was observed. In this case, the measurement results are shown in Table 4 and FIG. 8 .

Sterilization Effect (cell / mL) 0 min 1 minute 15 mins 0 mg / L 7.3 × 10 ³ 267 13 10 mg / L 7.5 × 10 ³ 242 14 15 mg / L 9.2 × 10 ³ 203 5 20 mg / L 8.5 × 10 ³ 157 Fully sterilized 25 mg / L 8.5 × 10 ³ 82 Complete sterilization after 10 minutes

As shown in Table 4 and FIG. 8 , when no hydrogen peroxide was added, a sterilizing effect of 96% was obtained at 267 cells / ml after 1 minute at 7.3 × 10 ³ cells / ml, and 13 cells / ml survived after 15 minutes. By 99.8% bactericidal effect. When 10 mg / L hydrogen peroxide was injected, it showed a bactericidal effect of 96.7% at 242 cells / ml after 1 minute at 7.5 × 10 ³ cells / ml, but slightly higher than that without the addition of 99.8%. A bactericidal effect of% showed a similar bactericidal effect. At 15 mg / L, it showed 97.8% bactericidal effect at 203 cells / ml after 1 min at 9.2 × 10 ³ cell / ml, and 157 cells after 1 min at 8.5 × 10 ³ cell / ml when 20 mg / L was added. It showed 98% bactericidal effect at / ml and after 15 minutes it was completely sterilized. When 25 mg / L of hydrogen peroxide was added, it showed a 99% sterilization effect from 8.5 × 10 ³ cells / ml to 82 cells / ml, and after 10 minutes, it was found to be completely sterilized. Therefore, the sterilization method by adding a small amount of hydrogen peroxide to the water can achieve the effect of greatly increasing the sterilization effect.

Experimental Example 4 Sterilization Effect on the Change of Treated Water Quantity

After increasing the amount of water treated twice in the photocatalytic reactor 10 of the present invention, the hydrogen peroxide concentration was adjusted to 20, 25, 30 and 50 mg / L, respectively, and 30 L / min of air was pumped into the photocatalytic reactor 10. 31) was observed for the bactericidal effect on E. coli while injecting. In this case, the measurement results are shown in Table 5 and FIG. 11 .

Sterilization Effect (cell / mL) 0 min 1 minute 2 mins 5 minutes 15 mins 0 mg / L 3.2 × 10 ⁴ 1.5 × 10 ⁴ 1.2 × 10 ⁴ 1.8 × 10 ³ 37 20 mg / L 3.8 × 10 ⁴ 1.1 × 10 ⁴ 7.0 × 10 ³ 1.8 × 10 ³ 15 25 mg / L 3.1 × 10 ⁴ 2.2 × 10 ⁴ 1.5 × 10 ³ 2 × 10 ² 4 30 mg / L 3.5 × 10 ⁴ 1.9 × 10 ⁴ 1.0 × 10 ³ 82 2 50 mg / L 3.4 × 10 ⁴ 1.1 × 10 ⁴ 8.5 × 10 ² 13 One

When hydrogen peroxide was not added according to Table 5 and FIG. 11 , 51% of the bactericidal effect was exhibited from 3.2 × 10 ⁴ cell / ml to 1.5 × 10 ⁴ cell / ml for 1 minute, and 1.2 × 10 ⁴ after 2 minutes. The cell / ml showed 62.3% bactericidal effect. After 5 minutes, 94.3% bactericidal effect was observed at 1.8 × 10 ³ cell / ml, and after 15 minutes, it was 99.8% bactericidal effect at 37 cell / ml. When 20 mg / L of hydrogen peroxide was added, it showed a 69.3% bactericidal effect from 3.8 × 10 ⁴ cell / ml to 1.1 × 10 ⁴ cell / ml for 1 minute, and 81.8 at 7.0 × 10 ³ cell / ml after 2 minutes. After 5 minutes, it showed 95.3% bactericidal effect at 1.8 × 10 ³ cell / ml, and after 15 minutes, 99.9% bactericidal effect was observed. When 25 mg / L of hydrogen peroxide was treated, it showed a 92.8% sterilization effect from 3.1 × 10 ⁴ cell / ml to 2.2 × 10 ³ cell / ml in 1 minute, and 95.2% sterilization at 1.5 × 10 ³ cell / ml in 2 minutes. After 15 minutes, a bactericidal effect of 99.98% was observed at 4 cells / ml. When 30 mg / L of hydrogen peroxide was added, it showed a 94.4% bactericidal effect from 3.5 × 10 ⁴ cell / ml to 1.9 × 10 ³ cell / ml for 1 minute, and after 9 minutes, 99.7% The bactericidal effect was shown and after 15 minutes, it showed 99.99% bactericidal effect at 2 cell / ml. In addition, when 50 mg / L of hydrogen peroxide was treated, it showed a 96.6% bactericidal effect from 3.4 × 10 ⁴ cell / ml to 1.1 × 10 ³ cell / ml for 1 minute, and 99.96% at 13 cell / ml after 5 minutes. After 15 minutes, only 1 cell / ml was observed, resulting in 99.99% bactericidal effect.

Experimental Example 5 Bactericidal Effect on Bacteria in Soybean Sprouts

In the sterilization experiment for the actual water, not E. coli in the buffer solution, the immersion water in which the bean sprouts were soaked was used as the water. 30 L / min air was injected into the photocatalytic reactor 10, and the sterilizing effect on the bacteria present in the soybean sprout immersion water was observed for 90 minutes while adjusting the concentrations of hydrogen peroxide to 0, 25, 50 and 75 mg / L, respectively. It was. In this case, the measurement results are shown in Table 6 and FIG. 12 .

Concentration of hydrogen peroxide 1 minute 15 mins 30 minutes 90 mins 0 mg / L 82.9% 99.7% 99.1% 99.5% 25 mg / L 82.6% 99.4% 99.5% 99.9% 50 mg / L 88.2% 99.8% 99.9% 99.99% 75 mg / L 91.2% 99.8% 99.99% Fully sterilized

According to Table 6 and FIG. 12 , the initial population of bacteria in the immersed water for 4 hours was 4.0 × 10 ⁴ cell / ml and showed a bactericidal effect of 82.9% at 6.8 × 10 ³ cell / ml for 1 minute. After 15 minutes, the sterilization effect was 99.7% at 123 cells / ml, but after 30 minutes, the sterilization effect was slightly decreased to 343 cells / ml, and then the sterilization effect was increased. It showed a bactericidal effect of 99.5%. When 25 mg / L of hydrogen peroxide was added, it showed 82.6% sterilization effect for 1 minute, 99.4% after 15 minutes, 99.5% after 30 minutes, and 99.9% after 90 minutes. The results were similar to those without addition, but after 90 minutes, at the end of sterilization, they showed a higher sterilization effect, and no intermediate sterilization effect was observed, such as when hydrogen peroxide was not added.

Hydrogen peroxide showed a bactericidal effect of 88.2% after 1 min with 50mg / L addition, 99.8% after 15min, 99.99% after 90min, 91.2% after 1min with 75mg / L injection, 99.8% after 15min, After 30 minutes it was observed that 99.99% and after 90 minutes they were completely sterilized. As described above, the sterilization test for soybean was slightly less effective than the test using Escherichia coli, and a slight increase in cell mass was observed at the end of the sterilization. However, in the experiment using E. coli, sterilization experiment was performed by injecting a certain amount of bacteria into the nutrient-free buffer, but the growth of the bacteria did not occur anymore. Because live nutrients act as bacteria because bacteria continue to grow and the number has increased. In addition, the addition of hydrogen peroxide shows more excellent disinfection effect than the addition of 50 mg / L.

Experimental Example 6 A bactericidal effect on fungi present in soybean sprout immersion water

In the same manner as in Experimental Example 5, the bactericidal effect on the fungi present in the soybean sprouted waters was observed. In this case, the measurement results are shown in Table 7 and FIG. 13 .

Concentration of hydrogen peroxide 1 minute 15 mins 90 mins 0 mg / L 69.3% 99.6% 99.7% 25 mg / L 71.1% 99.5% 99.88% 50 mg / L 90% Fully sterilized - 75 mg / L 93.7% 4 minutes after complete sterilization

According to Table 7 and FIG. 13 , the initial population of the fungus in the 4 hour immersion water was 1.0 × 10 ⁴ cell / ml and the bactericidal effect during 1 minute was 69.3%, after 15 minutes 99.6%, after 90 minutes 99.7% Bactericidal effect. When 25 mg / L of hydrogen peroxide was added, it showed a 71.1% bactericidal effect after 1 minute, 99.5% after 15 minutes, and 99.88% after 90 minutes. In the case of 50 mg / L, 90% after 1 minute, 99.8% after 10 minutes, and sterilization after 15 minutes were completed. When 75 mg / L was injected, it showed a 93.7% bactericidal effect after 1 minute and was completely sterilized after 4 minutes, and no mold was observed. In sterilization of the fungi, it was found that the bactericidal effect was much lower in the early stages than the bacteria, since the fungus is composed of stronger cell walls than the bacteria. In case of sterilization by adding hydrogen peroxide, the sterilization effect was higher even though the amount of hydrogen peroxide was added in this experiment than that of bacteria because of the difference of initial population in immersion water.

<Comparative Example 1> Sterilization effect according to the filling

To compare the sterilization effect of TiO ₂ -coated porous carrier and glass beads used as a photocatalyst, each carrier coated with TiO ₂ was filled in the photocatalytic reactor 10 and 15 minutes while injecting 30 L / min of air. Ultraviolet rays were irradiated to observe the bactericidal effect on E. coli. In this case, the measurement results are shown in Table 8 and FIG. 5 .

Sterilization Effect (cell / mL) 0 min 1 minute 15 mins Porous carrier 7.2 × 10 ³ 370 One glass marble 7.1 × 10 ³ 357 13

Table 8 and Figure 5 is 7.1 × 10 ³ cell during that compares the bactericidal effect on E. coli in the carrier and the glass beads the TiO ₂ coating porosity using a very large muscovite powder, 1 min For the glass beads TiO ₂ coating The germicidal effect was 95% from / ml to 357 cell / ml, and after 15 minutes, 13 individuals remained and showed 99.8% bactericidal effect.

In the case of the TiO ₂ coated porous carrier, the sterilization effect for 1 minute was 95% sterilization effect from 7.2 × 10 ³ cell / ml to 370 cell / ml, showing a sterilization effect similar to that of TiO ₂ coated glass beads. After 15 minutes, however, only 1 cell / ml remained, which was slightly better than glass beads with 99.9% bactericidal effect.

In addition, the coating of TiO ₂ on the glass beads has a difficulty in newly coating the glass beads after a certain time because the desorption over time. However, in the case of a carrier prepared using a high porosity, TiO ₂ solution was more easily penetrated into the porous interior than glass beads, and desorption was not observed due to the high temperature treatment.

Comparative Example 2 Sterilization Effect by Hydrogen Peroxide Without UV Irradiation

In order to compare the sterilization effect by hydrogen peroxide without UV irradiation, the sterilization effect of E. coli was observed after adding 25 mg / L of hydrogen peroxide without UV irradiation. In this case, the measurement result is shown in FIG. 9 .

According to FIG. 9 , the sterilization effect of hydrogen peroxide alone was only 51% after 15 minutes at a concentration of 25 mg / L hydrogen peroxide, which was completely sterilized after 5 minutes and no bacteria were detected. Therefore, the bacterium was not simply sterilized by hydrogen peroxide, and it was found that addition of hydrogen peroxide with ultraviolet irradiation showed high sterilization effect.

As described above, the method and apparatus for sterilizing water by the photocatalytic reaction of the present invention can shorten the sterilization time of the water, increase the sterilization effect according to the addition of air and hydrogen peroxide during sterilization, and can be made small in size. It can be installed at the place, and the photocatalytic reactor can be separated, so that the device can be easily washed and used for the sterilization of water very effectively.

Claims (13)

An apparatus for sterilizing water by a photocatalytic reaction through a photocatalytic reactor, A water reservoir for storing water, A photocatalytic reactor comprising an inlet, an outlet, and a porous carrier coated with a photocatalyst therein, an ultraviolet lamp, and an air inlet tube, An inlet pump located between the water reservoir and the photocatalytic reactor, An air pump for introducing air into the air inlet pipe, and And a sterilized water reservoir for storing the sterilized water through the photocatalytic reactor. The sterilization apparatus of claim 1, wherein the inlet and the outlet comprise a photocatalyst filter network for preventing the photocatalyst coated porous carrier from flowing out of the photocatalytic reactor. The sterilization apparatus according to claim 1, wherein the inlet and the outlet are arranged in diagonal directions at the top and bottom of the photocatalytic reactor in order to increase the residence time in the photocatalytic reactor. The sterilization apparatus according to claim 1, wherein the photocatalyst is TiO ₂ . The sterilizing apparatus according to claim 1, wherein the porous carrier is a dolomite having a diameter of 6 to 10 mm. The sterilization apparatus according to claim 1, wherein the ultraviolet lamps are configured in a horizontal direction inside the photocatalytic reactor, but each lamp maintains a predetermined interval. The sterilization apparatus according to claim 1, wherein the electrode portion of the ultraviolet lamp protrudes out of the photocatalytic reactor. The sterilization apparatus according to claim 1, wherein the air inlet pipe is perforated at predetermined intervals at the bottom of the photocatalytic reactor. The sterilization apparatus of claim 1, wherein the photocatalytic reactor is manufactured by sandwiching an O-ring between an inner and an outer frame for sealing. The sterilization apparatus according to claim 1, wherein the photocatalytic reactor is hermetically manufactured with transparent acrylic so that the inside thereof can be observed. The sterilization apparatus according to claim 1, wherein the photocatalytic reactors can be arranged in parallel. In the method of sterilizing water by photocatalytic reaction, using the sterilizing apparatus of claim 1, Water permeated with hydrogen peroxide is injected into a photocatalytic reactor filled with a photocatalytic coated porous carrier, A method of sterilizing water by a photocatalytic reaction comprising the step of injecting air into the air inlet tube and simultaneously irradiating ultraviolet rays. 13. A sterilization method according to claim 12, wherein 25 to 50 mg / L of hydrogen peroxide is added.