JP2022006685A - Air sterilization/purification method and apparatus - Google Patents

Abstract

To provide an air sterilization/purification method and apparatus capable of performing sterilization and purification more easily and at a high level using transition energy when transiting active oxygen species, generated by contacting oxygen in the air with an N-type semiconductor metal oxide placed under ultraviolet irradiation, to ground state oxygen.SOLUTION: An N-type semiconductor metal oxide supported on a material capable of acting as a contact cell is irradiated with near-ultraviolet rays having a wavelength of 180 to 360 nm to surface excite the N-type semiconductor metal oxide, and then an air flow is brought into contact with the surface-excited part of the N-type semiconductor metal oxide to generate singlet oxygen. Subsequently, visible light having a wavelength of 400 to 650 nm is irradiated to transit the singlet oxygen to ground state oxygen by stimulated emission of electromagnetic waves, and sterilization and purification are performed using the transition energy.SELECTED DRAWING: Figure 1

Description

The present invention relates to an air sterilization / purification method and device for purifying and sterilizing air for environmental conservation, preventing nosocomial infections in hospitals, preventing sick building syndrome, and sterilizing in air conditioning.

As a conventional method for sterilizing air, either a method of irradiating ultraviolet rays having a wavelength of 185 nm to diffuse ozone generated into the air or a method of sterilizing by irradiating ultraviolet rays with a germicidal lamp having a wavelength of 254 nm. , Or a method using these in combination has been used.

In Patent Document 1 below, active oxygen species are generated by surface excitation of N-type semiconductor metal oxides by irradiating N-type semiconductor metal oxides in a ground oxygen atmosphere with near-ultraviolet rays having a wavelength of 180 to 360 nm. Stimulated oxygen is excited by optical pumping to generate singlet oxygen, and then visible light with a wavelength of 600 to 650 nm and near infrared rays with a wavelength of 1200 to 1300 nm are sequentially irradiated to generate singlet oxygen, which is an active oxygen species. The present inventor has proposed a method for sterilizing, deodorizing, and purifying air by sterilizing, deodorizing, and purifying with transition energy to basal state oxygen by stimulated emission of oxygen electromagnetic waves, and a device thereof.

Japanese Unexamined Patent Publication No. 8-57032

However, the conventional method of diffusing ozone into the air requires that ozone be released into the atmosphere as residual ozone before it is sufficiently decomposed, which not only has a great impact on the human body but is also difficult to handle. There was a point.
Further, since the method of irradiating ultraviolet rays with a germicidal lamp does not utilize the transition energy of oxygen, there is a problem that the portion not irradiated with ultraviolet rays cannot be sterilized or purified.

On the other hand, in the sterilization / deodorization / purification method and device of Patent Document 1, it is not necessary to diffuse ozone into the air, and since the air is sterilized / purified, there are no parts that cannot be sterilized or purified, and environmental conservation is achieved. It is suitably used for various purposes such as purifying and sterilizing air for various purposes, preventing nosocomial infections in hospitals, preventing sick building syndrome, and sterilizing in air conditioning, but it enhances the ability of sterilization and purification. Further improvements such as simplification of structure and processing were desired.

The present invention is intended to solve problems in conventional methods and devices for sterilizing and purifying air, and an object thereof is to convert oxygen in the air into an N-type semiconductor metal oxide under ultraviolet irradiation. To provide an air sterilization / purification method and device capable of sterilizing / purifying more easily and highly by making contact and transitioning the generated active oxygen species to basal state oxygen and using the transition energy. It is in.

The method for sterilizing and purifying air according to the present invention aims to achieve the above-mentioned object, and irradiates an N-type semiconductor metal oxide supported on a material having a contact battery action with near-ultraviolet rays having a wavelength of 180 to 360 nm. When the surface of the N-type semiconductor metal oxide is excited, an air flow is brought into contact with it to generate singlet oxygen, and then visible light having a wavelength of 400 to 650 nm is irradiated to release the singlet oxygen by stimulated emission of electromagnetic waves. It is characterized by transitioning to basal oxygen and using the transition energy to sterilize and purify.

In the present invention, the N-type semiconductor metal oxide film supported on the material capable of obtaining contact battery action is obtained by mixing zinc oxide (ZnO) powder in a conductive paint and applying and supporting it on a copper plate or copper plating. It is preferable that the charge of ZnO is increased by the contact battery action due to the potential difference between Cu and ZnO to promote the photocatalytic effect and increase the electron emission.

Further, in the air sterilization / purification device according to the present invention, the inner surface in contact with the air flow is composed of an N-type semiconductor metal oxide supported on a material capable of obtaining a contact battery action, and is in contact with the N-type semiconductor metal oxide. While shifting the air flow, the base state oxygen of the air flow is irradiated with near-ultraviolet waves having a wavelength of 180 to 360 nm, and singlet oxygen generated by surface excitation of the N-type semiconductor metal oxide and sequentially sent to the rear is generated. It is characterized by being provided with a light beam irradiating means that transfers singlet oxygen to basal oxygen by induced emission of electromagnetic waves by irradiating with visible light having a wavelength of 400 to 650 nm.

In the air sterilization / purification method of the present invention and the apparatus thereof, oxygen in the passing air flow generates ground state oxygen atoms when irradiated with ultraviolet rays having a wavelength of 180 to 360 nm.
O ₂ + hν (180-200 nm) → 2O (3p)
hν: Ultraviolet O (3p): Ground state oxygen atom Then, oxygen molecules in the air react with this ground state oxygen atom to generate ozone.
O (3p) + O ₂ → O ₃
O ₃ : Ozone

When this O ₃ is irradiated with ultraviolet rays having a wavelength of 250 to 300 nm, O ₃ is decomposed to generate singlet oxygen atoms and singlet oxygen molecules.
O ₃ + hν (250nm-300nm) → ¹ D + ¹ Δg
¹ D: Singlet oxygen atom
¹ Δg: Singlet oxygen molecule

On the other hand, when the N-type semiconductor metal oxide is irradiated with ultraviolet rays having a wavelength of 180 to 360 nm, electrons are emitted, the electrons are donated to the ground state oxygen, and the oxygen is excited and radicalized to generate an active oxygen anion.
hν (180-360nm) + M → e-
M; N-type semiconductor metal oxide e-: Electron O ₂ + 2e- → O- + O- → O _2-
O-: Active oxygen anion

When the excited singlet oxygen atom or molecule is next irradiated with visible light having a wavelength of 400 to 650 nm, it transitions to a ground state oxygen molecule together with an active oxygen anion as appropriate.
2 ¹ Δg + hν (400 to 650 nm) → 2 ³ Σg
23 ^Σg : Ground state oxygen molecule Singlet oxygen is in an excited state with high energy of 22.5 Kcal / mol, so it exhibits a strong bactericidal action, and sterilization and purification of the passing air flow is performed promptly. Is.

Therefore, according to the air sterilization / purification method and apparatus of the present invention, the active oxygen species generated by contacting oxygen in the air with an N-type semiconductor metal oxide under ultraviolet irradiation is transferred to basal oxygen. When sterilizing and purifying, it is possible to perform sterilization and purification more easily and highly by using transition energy.

It is sectional drawing which showed the structure of the sterilization / purification apparatus which concerns on this embodiment. It is a top view which showed the garbage collection room which installed the sterilization / purification apparatus which concerns on this embodiment.

Hereinafter, the air sterilization / purification method will be described in detail with reference to the drawings together with an example of the air sterilization / purification device of the present invention.
FIG. 1 is a cross-sectional view showing the configuration of the sterilization / purification device according to the present embodiment.
In the air sterilization / purification device of this embodiment, the casing 9 is provided with an air suction port 2a for sucking the contaminated air 1a and an air discharge port 2b for discharging the sterilized / purified air 1b. A meandering duct 3 continuous between the air suction port 2a and the air discharge port 2b is provided inside the casing 9.

An axial flow fan 7 driven by a motor is attached to an air discharge port 2b, and air 1a is sucked from an air suction port 2a by the axial flow fan 7, flows as an air flow along a meandering duct 3, and air 1b. The air is discharged from the air discharge port 2b, and the meandering duct 3 is located between the upstream side of the meandering duct 3 on the air suction port 2a side and the downstream side of the air discharge port 2b. Lamps 4, 5 and 6 for irradiating the inner surface and the air flow flowing in the meandering duct 3 with predetermined light are arranged.

In the meandering duct 3, a plurality of upward flow paths 3a and downward flow paths 3b are adjacent to each other with a hanging wall 3c interposed therebetween and are folded up and down continuously, so that an air flow flows from an air suction port 2a to an air discharge port 2b. It is provided to meander up and down repeatedly until it flows.

A photocatalyst layer 3d is provided on the inner surface of the meandering duct 3 in contact with the air flow and the inner surface of the casing 9. In the present embodiment, the entire inner surface of the meandering duct 3 and the casing 9 is composed of the photocatalyst layer 3d.
The photocatalyst layer 3d is composed of an N-type semiconductor metal oxide supported on a material capable of obtaining a contact battery action.

Specifically, as the photocatalyst layer 3d, for example, a conductive paint mixed with zinc oxide (ZnO) powder and coated and supported on a copper plate or copper plating can be used. As a method of supporting, it can be realized by adopting a sputtering method as an example.
In such a photocatalytic layer 3d, a contact battery action can be obtained by the potential difference between Cu and ZnO, and it is possible to increase the charge of ZnO to promote the photocatalytic effect and increase electron emission.

The copper plate or copper plating constituting the inner surface of the meandering duct 3 may be the casing 9 or the meandering duct 3 itself, or may be formed separately from these and arranged on the inner surface. The copper plate may be a non-deformable plate or a deformable film or laminate.

In such a meandering duct 3, a plurality of areas are provided between the upstream side on the air suction port 2a side and the downstream side on the air discharge port 2b side, and light of a predetermined wavelength is irradiated to each area. Lamps 4, 5 and 6 are installed for this purpose.
In the two areas on the upstream side, ultraviolet lamps 4 and 5 that irradiate near-ultraviolet rays having a wavelength of 180 to 360 nm to the ground state oxygen of the air flow that migrates while in contact with the N-type semiconductor metal oxide are arranged.
In the present embodiment, an ultraviolet lamp 4 that irradiates the most upstream area with ultraviolet rays having a wavelength of 182 nm is attached to the upper end of the hanging wall 3c. Further, in the next area, a plurality of ultraviolet lamps 5 for irradiating ultraviolet rays having a wavelength of 254 nm are mounted on the upper end and the side surface of the hanging wall 3c.

Further, in the area on the downstream side, a halogen lamp 6 that irradiates visible light having a wavelength of 400 to 650 nm to active oxygen species generated by surface excitation of an N-type semiconductor metal oxide and sequentially sent to the rear is arranged.
In the present embodiment, a halogen lamp 6 that irradiates visible light having a wavelength of 400 to 650 nm in the most downstream area is mounted so as to project from the center of the flow path. In the most downstream area of the meandering duct 3, the cross-sectional area of the flow path is provided to be larger than the other areas. Therefore, the flow velocity of the air flow flowing inside is reduced, and the visible light from the halogen lamp 6 can be sufficiently irradiated.

In the sterilization / purification device of the present embodiment, a ballast 10 for lighting each of these lamps 4, 5 and 6, a glow plug 11 and a terminal box for wiring collection are provided at the lower part of the meandering duct 3 of the casing 9. 12 and are installed.

In the air sterilization / purification method using such a sterilization / purification device, when the axial fan 7 is first rotated, the air 1a contaminated with bacteria such as bacteria and fungi, viruses, harmful substances, etc. is sucked into the air. It is continuously sucked into the meandering duct 3 from the mouth 2a.
In the meandering duct 3, the air flow sequentially flows to the downstream side while the conductive paint mixed with zinc oxide is in contact with the photocatalyst plate 3d coated on the copper plate.

The sucked air flow is first irradiated with ultraviolet rays having a wavelength of 182 nm by the ultraviolet lamp 4 on the most upstream side. Oxygen in the air flow passing by this produces ground state oxygen atoms.
Ozone is generated by the reaction of oxygen molecules in the air with this ground state oxygen atom.

Next, the air flow and the inner surface of the meandering duct 9 are irradiated with ultraviolet rays having a wavelength of 254 nm by the ultraviolet lamp 5. As a result, electrons are emitted from the photocatalyst layer 3d coated with zinc oxide, and the emitted electrons decompose ozone and transition to singlet oxygen atoms and singlet oxygen molecules to become oxygen anions.
Further, the electrons emitted by irradiating the N-type semiconductor metal oxide with ultraviolet rays having a wavelength of 254 nm are donated to the ground state oxygen in the air flow, and the oxygen is excited and radicalized to generate an active oxygen anion.

Next, the excited singlet oxygen atom and molecule are irradiated with visible light having a wavelength of 400 to 650 nm by the halogen lamp 6. As a result, singlet oxygen atoms and molecules shift to ground state oxygen. Since this singlet oxygen is in an excited state with a high energy of 22.5 Kcal / mol, it can exhibit a strong sterilizing / purifying action against the surrounding air flow at the time of migration.
For example, bacteria and fungi existing in the air stream can be sterilized, and harmful substances in an unstable state due to electron deficiency can be made stable substances and detoxified by giving oxygen. Furthermore, since the protein of a virus or the like is composed of carbon, hydrogen, oxygen, and nitrogen, this oxygen can be inactivated by receiving ultraviolet rays to generate active oxygen species inside.

At this time, in the present embodiment, the photocatalyst layer 3d is a material in which an N-type semiconductor metal oxide is supported on a material capable of obtaining a contact battery action, and in particular, zinc oxide (ZnO) powder is mixed with a conductive paint to form a copper plate. Alternatively, since it is coated and supported on a copper plating, the potential difference of Cu—ZnO can be utilized to increase the potential of ZnO by the action of a contact battery.
Therefore, it is possible to transfer singlet oxygen to basal state oxygen without irradiating light with a large wavelength such as near infrared rays, and it is possible to reduce the amount of light to irradiate, simplifying sterilization / purification equipment and methods, and powerfully sterilizing.・ It can be purified.
Then, the air 1b revived in this way and sterilized / purified is discharged from the axial fan 7 to continue the sterilization / purification treatment.

According to the air sterilization and purification method using the sterilization / purification device of the present embodiment as described above, the air flow flowing into and flowing into the meandering duct 3 and the casing 9 is the N-type semiconductor on the inner surface thereof. It flows while in contact with the metal oxide.
At that time, since the N-type semiconductor metal oxide is supported on the material that can obtain the contact battery action, the generation of singlet oxygen by the excitation of the ground state oxygen by the optical pumping of the active oxygen species generated by the surface excitation and the photocatalytic action. Can be increased synergistically.

Then, by causing the stimulated emission of electromagnetic waves by irradiating this singlet oxygen with visible light, it is possible to realize instantaneous sterilization and purification by the powerful energy at the time of transition to the ground state oxygen.
Moreover, since residual ozone in the air flow is not released, it does not affect the human body.

Therefore, it is possible to prevent nosocomial infections and to sterilize the inside of buildings, transportation facilities, and living spaces. Furthermore, it can be effectively used as an air supply device or method for food processing places such as kitchens and food factories and places where aseptic spaces are required such as medical institutions.

Next, the sterilization / purification device of the embodiment as shown in FIG. 1 is installed in a test place consisting of a closed space as shown in FIG. 2, and the number of airborne bacteria and the number of fallen bacteria before and after the operation of the sterilization / purification device 20 are performed. Was measured.
The measurement location is the Yokohama Kanazawa High-Tech Center Building Basement Garbage Collection Room (1-1-1, Fukuura, Kanazawa-ku, Yokohama City, Kanagawa Prefecture), and the size is 3.90m x 2.07m x 2.05m, and the volume is about 16m ³ . rice field. A plan view of the swill collection chamber is shown in FIG.

In the measurement, as shown in FIG. 2, the sterilization / purification device 20 is installed on the floor on the entrance / exit 21 side, and the sterilization / purification device 20 is installed at the measurement points A on the entrance side and the measurement point B on the back side of the shelves 22 and 23. The number of airborne bacteria and the number of fallen bacteria were measured for bacteria and fungi in the state before the operation and the state after the operation for 30 minutes.

The number of airborne bacteria was measured by the air sampler method using Air Sampler BSC (manufactured by Biotest) as an air sampler and an air suction amount of 160 L.
For the culture, Agar Strips TC (manufactured by Biotest) was used as a medium for bacteria, and Agar Strips YM (manufactured by Biotest) was used as a medium for fungi. Bacterial culture conditions were 30 ° C. for 3 days, and fungal culture conditions were 25 ° C. for 7 days.

On the other hand, for the number of fallen bacteria and fungi, two measuring media were placed at each of the measurement points A and B with the lid open for 30 minutes, and then the lid was closed for culturing.
For the culture, a standard agar medium (manufactured by Eiken Chemical Co., Ltd.) was used as a medium for bacteria. As the fungal medium, a potato dextrose agar medium (manufactured by Eiken Chemical Co., Ltd.) supplemented with 100 ppm of chloramphenicol was used. Bacterial culture conditions were 30 ° C. for 3 days, and fungal culture conditions were 25 ° C. for 7 days.

Table 1 shows the measurement results of the number of airborne bacteria and the number of fallen bacteria. The number of fallen bacteria was taken as the average value of the two media.

As is clear from the results in Table 1, both the number of airborne bacteria and the number of fallen bacteria were measured at measurement points A and B after 30 minutes of operation compared to before operation of the sterilization / purification device 20. It decreased significantly, and a sufficient bactericidal effect could be confirmed.

1a Contaminated air 1b Air that has been sterilized and purified 2a Air suction port 2b Air discharge port 3 Serpentine duct 3a Upward flow path 3b Downward flow path 3c Hanging wall 3d Photocatalyst layer 4 UV lamp with wavelength 182 nm 5 Wavelength 254nm UV lamp 6 Visible light halogen lamp with wavelength 400-650nm 7 Axial flow fan 9 Casing 10 Stabilizer 11 Glow plug 12 Terminal box 20 Sterilization / purification device 21 Doorway 22, 23 Shelf

Claims (3)

The N-type semiconductor metal oxide supported on the material having a contact battery action is irradiated with near-ultraviolet rays having a wavelength of 180 to 360 nm, and when the surface of the N-type semiconductor metal oxide is excited, the air flow is brought into contact with the single term. After producing oxygen
Air sterilization / purification characterized by irradiating visible light with a wavelength of 400 to 650 nm to transition singlet oxygen to ground state oxygen by stimulated emission of electromagnetic waves and sterilizing / purifying using the transition energy. Method. The N-type semiconductor metal oxide film supported on the material having a contact battery action is obtained by mixing zinc oxide (ZnO) powder into a conductive paint and applying and supporting it on a copper plate or copper plating. Cu and ZnO The method for sterilizing and purifying air according to claim 1, wherein the charge of ZnO is increased by the action of a contact battery due to the potential difference of the above, the photocatalytic effect is promoted, and the electron emission is increased. The inner surface in contact with the air flow is composed of an N-type semiconductor metal oxide supported on a material that has a contact battery function.
The air flow is transferred while in contact with the N-type semiconductor metal oxide, the ground state oxygen of the air flow is irradiated with near-ultraviolet waves having a wavelength of 180 to 360 nm, and the N-type semiconductor metal oxide is generated by surface excitation. It is characterized by being equipped with a light irradiation means that transitions the singlet oxygen to the ground state oxygen by stimulated emission of electromagnetic waves by irradiating the singlet oxygen sent backward in sequence with visible light having a wavelength of 400 to 650 nm. Air sterilization / purification device.

Images