JP2000167435A - Generating method of negative ion and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a negative ion generating method and the device capable of effectively generating pure negative ion in outside space. SOLUTION: In the negative ion generating method 1 having a photoelectron emitting material 14, an electrode 6 for electric field and an irradiation source 5 for irradiating the photoelectron emitting material with ultraviolet ray and/or radial ray in the space, the photoelectron emitting material 4 and the electrode 6 for electric field are composed of two parts forming different electric fields of the electric fields 4-1, 6-1 for purifying by the removal of the particles and the electric fields 4-2, 6-2 for negative ion generating and a photocatalyst and/or an adsorbent to purify the negative ion generating gas can be installed in the space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the generation of negative ions, and more particularly, to a method and an apparatus for generating negative ions by irradiating a photoelectron emitting material with ultraviolet rays and / or radiation.

[0002]

2. Description of the Related Art Conventionally, as a method of generating negative (negative) ions, a method of applying a negative high voltage to an electrode has been known, but this method has problems of generation of ozone and generation of fine particles. Was. Further, since high voltage electricity is used, there is a problem in safety. For this reason, the appearance of a new method that has solved these problems has been expected. That is, in the field of a comfortable working space (amenity), there is a demand for a comfortable and clean space for the living body that does not impair the metabolic function and physiological function of the living body without any difficulty. In addition, in the field of advanced industries such as semiconductors and liquid crystals, an ozone-free, electrically stable (low potential) ultra-clean space (work space) free of fine particles and gaseous pollutants (eg, organic gas, NH ₃ ). ) Is required.

In the current working space, both positive and negative ions are present, but there are many cases where the number of positive ions becomes excessive due to the contents of work and natural phenomena. One of the reasons for this is
Negative ions have higher mobility (moving speed is faster) than positive ions, so negative ions move faster and are consumed. As a result, it is considered that positive ions become excessive. (1) Negative ions are extremely reduced in a closed room or working space. (2) Normal floating fine particles are positively charged by airflow. (3) In a clean room of a semiconductor factory, there are many positively charged fine particles and air molecules due to space discharge by a high-voltage power supply and molecular friction in a work place. In addition, control (removal and management) of gaseous pollutants was insufficient. Such an atmosphere causes a decrease in product yield (eg, an increase in particle contamination due to generation of static electricity, an increase in electrostatic damage due to organic (gaseous pollutant) contamination to the substrate).

[0004] It is also said that a person changes their physical condition due to a decrease in the concentration of negative ions. (I get sick). That is, the human body is made up of countless cells, each of which is wrapped in cells, and which absorbs nutrients through its membranes and excretes waste products. These cells have positive ions on the outside and negative ions on the inside, and when the amount of negative ions decreases and the amount of positive ions becomes excessive, a phenomenon occurs in which it becomes difficult to absorb nutrients and excrete waste products. It is thought to cause a decline in function. Under such circumstances, the present inventors have previously proposed a negative ion generation method using a photoelectron emitting material. The proposed invention is illustrated below. (1) JP-B-8-10616, (2) JP-A-7-106
57643, (3) Japanese Patent Application Laid-Open No. 7-293939 These proposed methods and apparatuses are effective depending on the place of use, but depending on the place of use, it is necessary to further improve and improve the practicality. .

The improvement of these methods will be described. FIG.
FIG. 1 is a schematic configuration diagram of an air purifier (comfort air generator) for removing particles and generating negative ions (Japanese Patent Laid-Open No. 7-29393).
No. 9). The air purifier includes a fan 2, a coarse filter 3 for sucking and discharging air, and a photoelectron emission material 4-.
1. An ultraviolet lamp (germicidal lamp) 5-1; a photoelectron emission electrode 6-1; and a charged / collected part (A) for fine particles by photoelectrons, comprising a charged particle collecting electrode plate 7; Material 4-2, UV lamp (germicidal lamp) 5-
2. It comprises a negative ion generator (B) comprising a photoelectron emission electrode 6-2. Each operation will be described.
The coarse filter 3 collects coarse particulate matter in the air. The charging / collecting section (A) for the fine particles generates photoelectrons by irradiating the photoelectron emitting material 4-1 with ultraviolet rays from an ultraviolet lamp 5-1 under an electric field (50 V / cm), and the photoelectrons are regenerated. The fine particles are charged, and the charged fine particles are collected and removed by the charged particle collecting electrode material 7. The electrode (positive) 6-1 is for forming an electric field with the photoelectron emitting material (negative) 4-1.

The negative ion generating section (B) generates photoelectrons by irradiating the reticulated photoelectron emitting material 4-2 with ultraviolet rays from an ultraviolet lamp 5-2 under an electric field, and generates negative ions by the photoelectrons. It is to let. Numeral 8 denotes inlet air, and numeral 9 denotes negative ion-enriched dust-free air. With such a configuration, the negative ion-enriched air 9 needs to be provided with a separate negative ion generator (B) behind the charge / collection unit (A) for the fine particles by photoelectrons. There were problems such as the increase in size, cost, and complexity of maintenance and inspection, and there was room for improvement. Further, in the above, dust-removed negative ions can be obtained, but depending on the application and the applied device, it is necessary to further remove gaseous pollutants, and there is room for improvement.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and provides a negative electrode capable of effectively generating clean (contaminant-collected and removed) negative ions in an external space. An object of the present invention is to provide a method and an apparatus for generating ions.

[0008]

According to the present invention, an electric field is formed in a space between a photoelectron emitting material and an electrode for an electric field, and under the electric field, ultraviolet light and ultraviolet light are applied to the photoelectron emitting material. And / or a method for generating negative ions by irradiating radiation, wherein two different electric fields for cleaning by particle removal and for generating negative ions are formed between the photoelectron emitting material and the electric field electrode. is there. Further, according to the present invention, in a negative ion generator having a photoelectron emitting material, an electric field electrode, and an irradiation source for irradiating the photoelectron emitting material with ultraviolet light and / or radiation, the photoelectron emitting material and the electric field The electrode is made up of two parts which form different electric fields for cleaning by particle removal and for generating negative ions. In the present invention, the space may be provided with a photocatalyst and / or an adsorbent for purifying the negative ion generating gas, and the space may be cleaned.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made based on the following four findings. (1) When the photoelectron emitting material is irradiated with ultraviolet light and / or radiation under an electric field, photoelectrons are emitted from the photoelectron emitting material, and the emitted photoelectrons are changed to negative ions. [(A)
JP-B-8-10616, (b) Aerosol research,
Vol. 8, No. 3, P239-248, 1993]. Since the negative ions (negative ion-enriched gas) are ozone-less, they can be suitably used in various fields. For example, it can neutralize excess positive ions in the semiconductor, liquid crystal and precision machinery industries. In the amenity, that is, the space where the negative ions are enriched, a comfortable feeling (exhilaration) is obtained for the human body. In the food field, it can be used to maintain the freshness of foods and to prevent the growth of fungi. In the use of negative ions, a negative ion-enriched gas that has been cleaned (removed of particulate matter and gaseous substances) depending on the place of use and the type of equipment is useful (preferably practical).

(2) U which has already been proposed by the present inventors
V / photoelectron method [eg, documents (b) and (c) Ebara Hourly, No. 164, P11 to 19, 1994 in the above (1)]
Is effective for removing particles, and has no merits such as no-noise air treatment because it is fanless, and no generation of secondary pollutants such as ozone-less. In addition, since an ultraviolet lamp is used, when a photocatalyst is installed in the vicinity, harmful gases (eg, organic gas) and odorous gases are simultaneously removed by photocatalysis [eg, (d) air cleaning, 35th
Vol. 3, No. 5, P51-58, 1997, (e) Ebara Hourly Report, No. 180, P3-41, 1998]. Further, by adding a cleaning unit using an adsorbent, harmful gas and odorous gas are simultaneously treated. The addition of a photocatalyst as the cleaning means and activated carbon or ion exchange fiber as an adsorbent can be added to the UV / photoelectron method depending on the application destination (apparatus type and shape), required specifications, and economy.

(3) As a conventional method of generating negative ions,
In corona discharge, ozone generated has a negative effect, so ozone-less negative ions are practically needed [(f) 12th Aerosol Science and Technology Research Symposium,
p. 120-122, 1995, (g) Proceedings of the Air Conditioning and Sanitary Engineering Society Academic Lecture Meeting, p. 1065-106
8, 1995]. The generation of negative ions by the UV / photoelectron method is effective when the concentration of fine particles (particles) in the air is set to 10 million / ft ³ or less in advance (Japanese Patent Application Laid-Open No. 7-1995).
293939). This is because the released negative ions are collected (consumed) by the particulate matter when the particulate matter coexists in high concentration.
Is to decrease. (4) In the use of negative ions, dust-removed negative ion-enriched air is preferable. Therefore, in the method using photoelectrons,
In order to remove dust and generate negative ions, a dust removing unit using photoelectrons was installed in the front, and then a negative ion generating unit was installed behind (see FIG. 8). On the other hand, by forming the electrode (electric field) in the charged portion of the fine particles using photoelectrons with two parts, one for removing particles and the other for extracting negative ion pairs, negative ions can be emitted to outside with a compact device.

Next, each configuration of the present invention will be described in detail. The photoelectron emitting material is used for the purpose of generating photoelectrons for charging and collecting particles (particulate matter) and / or generating negative ions behind the photoelectrons. The photoelectron emitting material may be any material that emits photoelectrons when irradiated with ultraviolet light and / or radiation, and the smaller the photoelectric work function, the better. In terms of effect and economy, Ba, Sr, Ca,
Y, Gd, La, Ce, Nd, Th, Pr, Be, Z
r, Fe, Ni, Zn, Cu, Ag, Pt, Cd, P
b, Al, C, Mg, Au, In, Bi, Nb, Si,
Any of Ti, Ta, U, B, Eu, Sn, P, and W, or a compound or alloy or a mixture thereof is preferable, and these are used alone or in combination of two or more. As the composite material, a physical composite material such as amalgam can be used.

For example, compounds include oxides, borides and carbides, and oxides include BaO, SrO, and Ca.
_{O, Y 2 O 5, Gd} 2 O 3, Nd 2 O 3, ThO 2, ZrO 2,
Fe ₂ O ₃ , ZnO, CuO, Ag ₂ O, La ₂ O ₃ , Pt
_{O, PbO, Al 2 O3,} MgO, In 2 O 3, BiO,
NbO, BeO, etc., and borides include Y
B ₆ , GdB ₆ , LaB ₅ , NdB ₆ , CeB ₆ , EuB ₆ ,
PrB ₆ , ZrB _{2 and the} like.
C, ZrC, TaC, TiC, NbC, WC and the like. In addition, brass, bronze, phosphor bronze, an alloy of Ag and Mg (Mg is 2 to 20 wt%), an alloy of Cu and Be (Be is 1 to 10 wt%), and an alloy of Ba and Al are used as the alloy. The alloy of Ag and Mg, Cu
An alloy of Ba and Be and an alloy of Ba and Al are preferred. The oxide can also be obtained by heating only the metal surface in air or oxidizing it with a chemical.

Further, as another method, it is possible to obtain an oxide layer which is stable for a long time by heating before use to form an oxide layer on the surface. As an example, an oxide film can be formed on the surface of an alloy of Mg and Ag in water vapor at a temperature of 300 to 400 ° C., and this oxide film is stable for a long period of time. . These substances can be used in bulk (solid or plate) or added to an appropriate base material (support) (Japanese Patent Application Laid-Open No. Hei 3-1086).
No. 98). For example, it can be added to the surface of or near the surface of the ultraviolet ray transmitting substance (Japanese Patent Publication No. 7-93098). The method of addition may be any method as long as photoelectrons are emitted by irradiation of ultraviolet rays and / or radiation.

[0015] For example, a method of coating onto a glass plate for use, as another example, a method of embedding near the surface of a plate-like material, or a method of coating on a plate-like material and further coating another material thereon And a method of using a mixture of an ultraviolet-transmissive substance and a substance that emits photoelectrons. In addition, a method of adding in a thin film shape, a method of adding in a net shape, a linear shape, a granular shape, an island shape, a belt shape, or the like can be appropriately used. A method of adding a material that emits photoelectrons can be made by coating or adhering the surface of an appropriate material by a known method. For example, an ion plating method, a sputtering method, an evaporation method, a CVD method, a plating method, a coating method, a stamp printing method, and a screen printing method can be appropriately used.

The thickness of the thin film may be a thickness at which photoelectrons are emitted by irradiation of ultraviolet rays or radiation, and may be 5 to 5,0.
00 °, usually 20 ° to 500 °. The base material can be used in plate, pleated, cylindrical, rod, linear,
There are a net shape, a fiber shape, a honeycomb shape and the like, and the surface shape can be appropriately made uneven to use. Further, the tip of the convex portion may be sharpened or spherical (see Japanese Patent Publication No.
74908). As for the addition of the thin film to the base material, as already proposed by the present inventors, one kind or two or more kinds of materials can be used in a single layer or a multilayer. That is, a plurality of thin films can be used as appropriate (composite) to form a double structure or a multi-layer structure of more than that (Japanese Patent Application Laid-Open No. 4-1522).
No. 96). It is preferable to use the photoelectron emitting material depending on the application destination because it is self-cleaning, that is, the photoelectron emitting material is removed even if a contaminant adheres, when used integrally with a photocatalyst described later. As such a material, a Ti material is oxidized and T
There is one in which iO ₂ is generated and Au is added thereon.

In the above, the shape of the photoelectron emitting material is preferably a shape that allows the processing gas to pass through. Such shapes include mesh, fiber, and line. When the photoelectron emission material having such a shape is installed so as to pass through the processing gas, an electric field for photoelectron emission to be described later is advantageously weakened. The optimal shape, the type and addition method of the material that emits photoelectrons by irradiation of ultraviolet light and / or radiation, and the thickness of the thin film are determined by the type, scale, shape, type of photoelectron emitting material, type of base material,
Preliminary tests can be carried out as appropriate according to the strength of the electric field, how to apply the electric field, effects, economy, and the like, which will be described later. When the photoelectron emitting material is used in addition to the base material, the base material may be ceramic, clay, or a well-known metal material in addition to the above-described ultraviolet ray transmitting material. Alternatively, the surface of a light source described below can be coated with the above-mentioned photoelectron emitting material (the light source and the photoelectron emitting material are integrated) (Japanese Patent Laid-Open No. 4-243540).

Next, an irradiation source for irradiating the photoelectron emitting material with ultraviolet light and / or radiation will be described. The irradiation source may be any source that generates photoelectrons by irradiating the photoelectron emitting material under an electric field. In addition, when a photocatalyst is added, any photocatalyst can be used as long as the photocatalyst exerts a photocatalytic action by the irradiation. The ultraviolet light emitted from the ultraviolet light source generates a comfortable negative ion from the photoelectron emitting material, and at the same time, by irradiating the photocatalyst, the photocatalyst exerts a photocatalytic action, which is one of the features of the present invention. . As such an ultraviolet light source, a mercury lamp, a hydrogen discharge tube, a xenon discharge tube, a Lyman discharge tube or the like can be used as appropriate. Examples of the light source include a germicidal lamp, a black light, a fluorescent chemical lamp, a UV-B ultraviolet lamp, and a xenon lamp.

Among them, a germicidal lamp (wavelength: 254 nm)
Is preferable because it has a bactericidal (sterilizing) action on suspended fungi and microorganisms coexisting with particles (particulate matter). That is, by using a germicidal lamp as an ultraviolet light source, complete sterilization (sterilization) is performed by irradiating various fungi and microorganisms collected in the collecting portion at the same time as collecting and removing particulate matter. It is preferable depending on the application destination (type of device) and required performance. Irradiation with radiation may be performed by any method as long as the photoelectron emitting material can emit photoelectrons by the irradiation, and the radiation can be performed by a conventionally known method. For example, α-rays, β-rays, γ-rays and the like are used as the radiation, and radioactive isotopes such as cobalt 60, cesium 137, and strontium 90, or radioactive waste produced in a nuclear reactor and appropriate radioactive wastes are used as irradiation means. A method using a radioactive material that has been processed and processed as a source, a method using a nuclear reactor as a direct source,
A method using a particle accelerator such as an electron beam accelerator is used. The generation of photoelectrons by irradiating the photoelectron emitting material with ultraviolet rays and / or radiation is performed by forming an electric field (electric field) between the photoelectron emitting material (negative electrode) and an electrode (positive electrode) described later. Photoelectrons occur effectively.

Next, an electrode which is a feature of the present invention will be described. The electrode is installed to effectively generate photoelectrons from the photoelectron emitting material under an electric field, generates photoelectrons (negative ions) in front (upstream), and effectively charges the charged particles together with the charge. Has the role of collecting in
On the other hand, the rear (downstream) electrode discharges negative ions to the outside. In other words, the electric field between the photoelectron emitting material and the electrode is mainly composed of two parts, one for particle removal (particle removal part) at the front and the other for negative ion generation (negative ion generation part) at the rear. This is a feature of the present invention. Such an electrode is conductive and does not generate impurities (contaminants), and is formed of a conductive material having a well-known shape such as a plate shape, a net shape, a wavy shape, a pleated shape, a wool shape, and a porous shape. S
US, aluminum, tungsten, nickel, copper, C
A u-Zn material can be used as appropriate.

In these electrodes, the front electrode has a role of collecting charged particles as described above, and the electrode for this purpose has two functions of charging particles and collecting charged particles. Anything that can be effectively performed over time may be used. The electrode for this purpose preferably has a large surface area, such as an uneven surface, a wavy shape, a pleated shape, a wool shape, or a porous shape. Particularly preferably, the surface is uneven or porous. An electrode of this shape can be made by appropriately combining known conductive materials. For example,
A material in which meshes with different mesh sizes are laminated, a material in which the mesh is corrugated (folded) and processed so as to intersect at an angle in the direction of the corrugate (a plurality of corrugated meshes are laminated so as to have a large surface area. material),
A conductive metal porous body having a three-dimensional network skeleton by deforming (bending) a linear metal is available.

Next, the rear electrode will be described. The electrode is for generating negative ions, and the generation of negative ions is carried out by adjusting the concentration of the particulate matter in the inflowing processing gas to 10 million particles / ft ^{3 in} front of the above, preferably 10
It is preferable to perform the process after collecting and removing up to 100,000 particles / ft ³ or less. This means that the concentration of particulate matter is 10 million particles / ft ³
The reason for this is that by setting the value to 1 million / ft ³ or less, the generation of negative ions at the exit portion becomes effective. The reason why the generation of negative ions is effective when the particulate matter concentration is reduced in advance is unknown, but one reason is that when the coexisting particle concentration is high, the emitted photoelectrons are consumed by the particles. It is thought to be. That is, the negative ion for creating comfort of the present invention is a charged substance of a fine-sized substance as shown in the following reaction formula, and thus has a small charge and is considered to be monovalent. On the other hand, particles, for example, indoor suspended particles having a size of about
The negative ions are consumed by the particles because they retain a large charge such as zero valence.

The negative ion generator has a particle concentration of 1 in the gas.
10 million pieces / ft ³ or less, preferably 1 million pieces / ft ³
The following gases were collected at a negative ion concentration of 3,000 / ml.
100,000 / ml. Increasing the concentration of negative ions improves comfort (eg, pleasure for humans, maintaining freshness for foods and plants). here,
Generating negative ions, photoelectrons by electron attachment and clustering of the electron affinity of the large water molecules and oxygen molecules, O ₂ ^-
It is considered to form negative ion clusters such as (H ₂ O) _n , O ⁻ (H ₂ O) _n , and OH ⁻ (H ₂ o) _n . These reactions are shown below. ^{_{O 2 + e → O 2 -}} O 2 + H 2 O → O 2 - (H 2 O) · · · O 2 - + (H 2 O) n-1 + H 2 O → O 2 - (H 2 O) n

Generation of negative ions is effectively performed by irradiating the gas having the above particle concentration with ultraviolet light to the photoelectron emitting material under an electric field. The strength of the above-mentioned electric field is 0.5% because the particles in the gas are charged and collected at the same time in the front particle removing section.
Effective if KV / cm or more, 0.5 to 10 KV
/ Cm is a practically preferable range. That is, generally 10
This is because an application of KV / cm or more may cause a discharge phenomenon depending on the shape of the electrode, or may complicate the insulating structure due to a high voltage. On the other hand, the rear negative ion generating section may be weak because it only needs to generate negative ions.
00V / cm is a practically preferable range. The appropriate electric field strength can be determined by selecting an appropriate electrode and conducting a preliminary test in accordance with the shape of the device, required performance, and the like.

Next, the installation of the photocatalyst (cleaning by the photocatalyst) will be described. The photocatalyst is the particle removing unit,
Any device may be installed as long as it can be installed in the negative ion generating section and decomposes and removes gaseous pollutants (hazardous gas and odorous gas) coexisting with particulate matter in gas by irradiation with ultraviolet rays and / or radiation. . Photocatalysts are generally preferred because semiconductor materials are effective, readily available, and have good workability. In terms of effects and economy, Se, Ge, Si, T
i, Zn, Cu, Al, Sn, Ga, In, P, As,
Sb, C, Cd, S, Te, Ni, Fe, Co, Ag,
Any of Mo, Sr, W, Cr, Ba, and Pb, or a compound, an alloy, or an oxide thereof is preferable, and these are used alone or in combination of two or more.

For example, the elements are Si, Ge, Se,
Compounds include AlP, AlAs, GaP, AlSb,
GaAs, InP, GaSb, InAs, InSb, C
dS, CdSe, ZnS, MoS ₂ , WTe ₂ , Cr ₂ T
e ₃ , MoTe, Cu ₂ S, WS ₂ , and Ti as an oxide
O ₂ , Bi ₂ O ₃ , CuO, Cu ₂ O, ZnO, MoO ₃ ,
InO ₃ , Ag ₂ O, PbO, SrTiO ₃ , BaTiO ₃
Co ₃ O ₄ , FeO ₃ , NiO, etc. For the immobilization of the photocatalyst, a well-known addition method such as a vapor deposition method / sputtering method, a sintering method, a sol-gel method, a coating method, or a baking method can be appropriately used for an appropriate material (base material). Additional shapes are thin film, linear, mesh, band,
Comb shape, granular shape, island shape and the like can be appropriately selected and used depending on a base material or the like to be described later. The above-mentioned Ti and Zn can be used as a photocatalyst by, for example, oxidizing plate-like Ti, and thus can be suitably used depending on the type of the device.

As an example of fixing the photocatalyst, a known conductive material such as SUS, Cu-Z
n, Al, or coating on the surface of ceramic, fluororesin, glass or glassy substance, or coating the photocatalyst on an appropriate material such as plate, granule, island, line, net, film or fiber Alternatively, it may be wrapped or sandwiched and fixed for use. An example is the coating of titanium dioxide on a glass plate by the sol-gel method. The photocatalyst can be used in the form of a powder, but can be used in an appropriate shape by a known method such as sintering, vapor deposition, or sputtering. Further, in order to improve the photocatalytic action, Pt, Ag, Pd, and Ru are added to the photocatalyst.
A substance such as O ₂ or Co ₃ O ₄ can be added for use. The addition of the substance is preferred because the photocatalysis is promoted. These can be used alone or in combination. Usually, the amount added is 0.01 to
It is 10% by weight, and an appropriate concentration can be selected by conducting a preliminary test according to the type of the added substance and the required performance. Well-known means such as an impregnation method, a photoreduction method, a sputter deposition method, and a kneading method can be appropriately used for the addition method.

The photocatalyst can be installed in the particle removing section or the negative ion generating section by any position and installation method as long as the ultraviolet rays and / or radiation from the ultraviolet light source and / or radiation source can be effectively irradiated. For example, there is (1) integration with the photoelectron emitting material (Japanese Patent Application No. 8-132563). For example, a method of adding a substance that emits photoelectrons onto the base material and a photocatalyst, There is a method of adding a photocatalyst to a substance which emits photoelectrons, and a method of adding a substance which emits photoelectrons to the photocatalyst. Another example is (2) integration with the electric field electrode material (Japanese Patent Application No. 8-231290). For example, a photocatalyst is added to a SUS material in a mesh or island shape (SUS is a positive electrode). A method of adding a photocatalyst to a ceramic film and sandwiching it with a reticular SUS material (S
US is a positive electrode), (3) Photocatalyst installation method in space where air flows, (4) Coating method on ultraviolet lamp (Japanese Patent Application No. 8-31231), etc. , Processing air conditions (concentration), required performance, etc.
Preliminary tests can be conducted as appropriate to determine the results. Usually, when the concentration of gaseous pollutants (eg, hydrocarbons) is high, it is preferable to install a photocatalyst in front of the charged portion of the particulate matter. That is, by installing a photocatalyst in this portion, gaseous pollutants are removed in advance, so that harmful substances such as hydrocarbons do not adhere to the photoelectron emission material, and a decrease in performance can be prevented, which is preferable. Higher gaseous contaminants are a preferred form.

Next, the installation of the adsorbent (cleaning by the adsorbent) will be described. The adsorbent, NO _X, SO _X in the gas, HCl, acid gases such as HF, ammonia, alkaline gas, such as an amine, may be a material to efficiently collect to low concentrations. Such adsorbents include silica gel, zeolite, alumina, activated carbon,
There are ion exchange fibers, of which activated carbon and ion exchange fibers are preferred because they are effective. As activated carbon,
Acid or alkali impregnated carbon can be used as appropriate depending on the method of combining the trapping components (the type of target gas) or ion exchange fibers. As the activated carbon, a known material can be used. Although the shape of the adsorbent can be used in an appropriate shape, a fibrous shape, a net shape, and a honeycomb shape are generally preferable because of a small pressure loss.

Next, the ion exchange fiber will be described.
Ion-exchange fibers can be used as gaseous pollutants in gaseous NH.
_3. Basic substances such as amines, SOx, NOx, H
It is effective for collecting and removing ionic contaminants such as acidic substances such as F and HCl. This is a material in which a cation exchanger or an anion exchanger, or an ion exchanger having both a cation exchange group and an anion exchange group is supported on the surface of a support such as a natural fiber or a synthetic fiber or a mixture thereof. As a method, the support may be directly supported by a fibrous support, or may be formed into a woven, knitted or flocked form and then supported. Further, an ion exchanger may be supported by the honeycomb-shaped base material. In any case, it is sufficient that the shape finally has a small pressure loss such as a fibrous shape supporting the ion exchanger.

As a method for producing ion-exchange fibers used in the present invention, ion-exchange fibers produced by using graft polymerization, particularly radiation graft polymerization, are suitable. This is because various materials and shapes can be used. Well, wool, silk, etc. can be applied as the natural fibers, and synthetic fibers made of a hydrocarbon polymer, those made of a fluorinated polymer, or polyvinyl alcohol, polyamide, polyester, poly Acrylonitrile, cellulose, cellulose acetate and the like can be applied. Examples of the hydrocarbon polymer include polyethylene, polypropylene, polybutylene, aliphatic polymers such as polybutene, polystyrene, aromatic polymers such as poly α-methylstyrene, alicyclic polymers such as polyvinylcyclohexane or These copolymers are used. Also,
Examples of the fluorinated polymer include polytetrafluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene tetrafluoride-propylene hexafluoride copolymer, vinylidene fluoride-propylene hexafluoride A copolymer or the like is used.

In any case, the support has a large contact area with the gas flow, a small resistance, a shape that can be easily grafted, a high mechanical strength, a loss of fiber waste, generation of heat and heat. Any material may be used as long as the material has little effect on the application, and it can be appropriately selected in consideration of the intended use, economy, effects, and the like. Usually, polyethylene is generally used, and polyethylene or a composite of polyethylene and polypropylene is particularly preferable. Next, as the ion exchanger, various cation exchangers or anion exchangers can be used without particular limitation. For example, in the case of cation exchange, for example, carboxyl groups, sulfonic acid groups, phosphoric acid groups, cation exchange group-containing substances such as phenolic hydroxyl groups, primary to tertiary amino groups, quaternary ammonium groups and the like Anion exchange group-containing body of
Alternatively, an ion exchanger having both the positive and negative ion exchange groups can be used.

Specifically, styrene compounds such as acrylic acid, methacrylic acid, vinylbenzenesulfonic acid, styrene, halomethylstyrene, acyloxystyrene, hydroxystyrene, aminostyrene, etc.
Vinylpyridine, 2-methyl-5-vinylpyridine, 2-
After graft polymerization of methyl-5-vinylimidazole and acrylonitrile, if necessary, sulfuric acid, chlorosulfonic acid, and sulfonic acid are reacted to obtain a fibrous anion exchanger having a cation or anion exchange group. . These monomers can also be graft-polymerized onto fibers in the presence of a monomer having two or more double bonds, such as divinylbenzene, trivinylbenzene, butadiene, ethylene glycol, divinyl ether, ethylene glycol dimethacrylate, and the like. Good. In this way, ion exchange fibers are manufactured. The diameter of the ion-exchange fiber is from 1 to 1000 μm, preferably from 5 to 200 μm, and can be appropriately determined depending on the type and use of the fiber.

The use of a cation exchange group and an anion exchange group among these ion exchange fibers can be determined depending on the type and concentration of the component to be removed in the target processing gas. For example, the component to be removed may be measured and evaluated in advance, and the type and amount of the ion exchange fiber corresponding to the measurement and evaluation may be used. Those having a cation exchange group (cation exchanger) when removing alkaline gas, those having anion exchange group (anion exchanger) when removing acidic gas, and those having a mixed gas of both. Fibers having both positive and negative exchange groups can be used. As the ion-exchange fibers, those produced by radiation graft polymerization as previously proposed by the present inventors are particularly advantageous because they are highly effective, and can be appropriately used (Japanese Patent Publication No. 5-9123, Japanese Patent Publication No. 67
No. 325, No. 5-43422, No. 6-246
No. 26). The ion-exchange fiber is effective for collecting ionic substances (components), and the acidic gas and alkaline gas targeted by the present invention are considered to be ionic substances. Can be removed.

In particular, the ion exchange filter (fiber) produced by radiation graft polymerization has a wide ion exchanger (anion and / or cation exchanger) since the irradiation of the support is uniformly performed to the inner part. Since it is firmly (strongly) added to the area (added at high density), the exchange capacity is large, and there is an effect that low-concentration ionic substances can be efficiently removed at a high speed, and it is practically effective. is there.
In addition, the production by radiation graft polymerization has advantages such as being able to be formed into a shape close to the product, being able to be performed at room temperature, being able to be performed in the gas phase, being able to increase the graft ratio, and being able to produce an adsorption filter with less impurities. Therefore, it has the following features. The ion exchange fiber (part of the adsorption function) is uniformly added to the ion-exchange fiber produced by the graft polymerization by irradiation with radiation (the addition density is high), so the adsorption speed is high,
Large amount of adsorption. Low pressure loss.

The installation of the photocatalyst and the adsorbent in the generation of negative ions according to the present invention can be determined by appropriate preliminary tests and studies in consideration of the application destination (type of apparatus), required performance, economy and the like. For example, (1) an air purifier that provides pleasure as well as dust removal and sterilization, and an air purifier (unit) that generates only negative ions may be used in a food case that maintains the freshness of foods and plants. (2) In (1), a photocatalyst is installed in an air purifier that removes gaseous pollutants such as odors and aldehydes. (3) In (1), an adsorbent is installed in an air purifier that removes gaseous pollutants such as NH ₃ and SO ₂ . The generation of negative ions according to the present invention may be any gas as long as it is a gas, and can be applied to gases such as air, N ₂ , Ar, and O ₂ .

[0037]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples. Embodiment 1 FIG. 2 is an explanatory diagram showing air purification in a hospital room 10. In FIG. 2, air 8 containing particulate matter 11 (dust, various fungi, microorganism-containing particles) is treated by the air purifier 1 of the present invention, and a clean space (c) in which a sick person 12 is sleeping.
Is supplied with clean air 9 enriched in negative ions. The inside of the sickroom 10 is contaminated by particulate matter invading from the outside and particulate matter (eg, Staphylococcus aureus) 11 generated from the sick person 12. In particular, the sick person 12 in the sickroom 10
Since fungi (eg, Staphylococcus aureus) are generated and the fungi are accumulated in the sickroom 11 and have a high concentration, there is a risk that the sick 12 may be infected by a visitor or a nurse. FIG. 1 shows a detailed configuration of the air purifier 1. The air purifier 1 includes a fan 2 for sucking and discharging air, a coarse filter 3, and a photoelectric emission material 4.
-1, 4-2, an ultraviolet lamp 5, an electrode 6-1 on which a mesh having a different mesh size in the front is laminated, and a rear plate electrode 6-
It consists of two. The photoelectron emission materials 4-1 and 4-2 are obtained by coating the ultraviolet irradiation window 13 with Au.

Next, each operation will be described. The coarse filter collects coarse particulate matter such as so-called dust in the air. The particulate matter 11 in the sickroom 10 is
By the operation of the fan 2, the particles are sucked into the particle collecting portion (particle charging / collecting portion, A). Here, 1,000 V / c
under an electric field of m [photoelectron emission material 4-1 (-) electrode and electrode 6-1]
When the photoelectron emission material 4-1 is irradiated with ultraviolet rays from the ultraviolet lamp 5 in the (+) electric field between the electrodes, the photoelectrons 14-1 are emitted. The particulate matter 11 attracted to the charging / collecting section (A) is charged by the photoelectrons 14-1 to become charged particles (charged particles) 15. Since the charged particles 15 have an electric charge, they move under the electric field by receiving a force in the direction of the electrode 6-1 and are collected and removed on the electrode (charged particle collecting material) 6-1.
Is done. The ultraviolet lamp 5 of this example is a sterilizing lamp, an electrode material 6
-1 is obtained by stacking three meshes made of SUS having different mesh sizes.

As described above, the particulate matter 11 in the room air 8 is stably collected on the electrode 6-1 for a long time.
In addition, ultraviolet rays (sterilization line from the germicidal lamp 5: 254 nm) are continuously irradiated to the collected particulate matter 16 on the electrode 6-1 for a long time, so that the biological particles collected on the electrode 6-1 are scattered. (Microorganisms such as Staphylococcus aureus, bacteria, and mold) are completely sterilized (sterilized). The air from which particles have been removed as described above is then subjected to negative ion generation in the negative ion generator (B). Here, under the electric field of 50 V / cm [the electric field between the photoelectron emission material 4-2 (-) electrode and the electrode 6-2 (+) electrode], the photoelectron emission material 4-2 is irradiated with the ultraviolet light to irradiate the photoelectrons as described above. 14-2 is released and negative ions are obtained. In this way, safe dust-free and sterilized negative ion-enriched air 9 is supplied to the hospital room 10. The clean air 9 is safe negative ion enriched high quality air and is a feature of the present invention. In FIG. 2, reference numeral 17 denotes a bet, and reference numeral 18 denotes a bed.

Second Embodiment FIGS. 3 and 4 show another embodiment of the air purifier 1 of FIG. 1 in the first embodiment. 3 and 4, the same symbols as those in FIGS. 1 and 2 have the same meaning. Next, a comparison with FIG. 1 will be shown for each embodiment. (1) In FIG. 3, a photocatalyst 19 for decomposing and removing odors (body odors: aldehydes, higher fatty acids, ammonia, etc.) as a gaseous contaminant in a portion exposed to the ultraviolet rays in FIG. 1 was installed. Things. The photocatalyst 19 is provided in the flow path in parallel to the direction of the irradiation ultraviolet light. Thereby, the negative ion-enriched air 9 from which particles and odorous gas have been removed
Is obtained. (2) FIG. 4 shows a case where an adsorbent (activated carbon and ion exchange fiber) 20 is installed in the three coarse filters of FIG.
Odor in hospital room due to adsorbent [body odor: basic gas such as ammonia or amine acid (mainly collected by ion exchange fiber)
And acidic gases such as fatty acids (mainly collected by activated carbon)]. Thereby, the negative ion-enriched air 9 from which particles and odorous gas have been removed is obtained.

Embodiment 3 FIG. 5 shows a clean air generation (dust removal of negative ion rich material) equipped with a particle removing section (A) and a negative ion generating section (B) installed in a class 1,000 clean room of a semiconductor factory. 1 shows an apparatus 1 for producing air. The apparatus 1 supplies negative ions 14-2 to the transfer device 21 in the clean room (for static elimination), and creates an electrically stable space. The apparatus 1 comprises a fan 2 for sucking air 1000 of class 1000 in a clean room and discharging the purified (dust-removed) negative ion-enriched air 9 obtained by the apparatus 1;
And a photoelectron emitting material 4-1, 4-2, an ultraviolet lamp (germicidal lamp) 5, an electrode 6-1 in which meshes of different mesh sizes are stacked on the front, and a mesh electrode 6-2 on the rear.
The photoelectron emitting materials 4-1 and 4-2 are obtained by coating a plate-shaped base with Au.

The operation of each will be described. The coarse filter 3 is for collecting coarse particulate matter in the air such as dust generated from the fan 2. Particle charging / collecting unit (A)
Is a photoelectron emission material 4 under an electric field (2,000 V / cm).
Is irradiated with ultraviolet rays from an ultraviolet lamp 5 to generate photoelectrons 14-1, the particles 11 are charged by the photoelectrons 14-1, and the charged particles 15 are collected by an electrode 6-1 (charged particle collecting material).・ Remove 16 Reference numeral 22 denotes a reflection surface for efficiently irradiating the ultraviolet rays from the ultraviolet lamp 5 to the photoelectron emitting materials 4-1 and 4-2, and reference numeral 23 denotes a quartz glass window. As described above, the air from which particles have been removed upstream is
Next, in the negative ion generator (B), the negative ions 14-
2 is generated.

Here, under the electric field of 50 V / cm [electric field between the photoelectron emission material 4-2 (-) electrode and the electrode 6-2], the photoelectron emission material 4-2 is irradiated with the ultraviolet light as described above to emit the photoelectrons. Is released, and negative ions 14-2 are obtained. The purified negative ion-enriched air 9 thus obtained is supplied to the transfer device 21, and the glass substrate 24 during transfer has a potential of 3,000 to 3,500 V before static elimination (D position). However, the voltage drops to 10 V or less after static elimination (position E). With this device 1, a class with a large number of positive ions of 1,000
Of the clean room air 8 is a clean air 9 having a negative ion concentration of 5,000 particles / ml and a class 1 (particle number of 0.1 μm particles in 1 ft ³ ) or less. The clean air 9
Is ozone-less, high-quality, negative-ion-enriched air that has been dedusted to class 1 or less, and is a feature of the present invention.

Embodiment 4 FIGS. 6 and 7 show another embodiment of the clean air generator 1 of Embodiment 3 shown in FIG. 6 and 7, the same reference numerals as those in FIG. 5 indicate the same meanings. Next, a comparison with FIG. (1) In FIG. 6, a photocatalyst 19 for removing organic gas (eg, phthalate ester) and ammonia in the clean room air as gaseous pollutants was installed in a portion irradiated with ultraviolet rays in FIG. Things. The photocatalyst 19 is
It is installed in the flow path in parallel with the direction of the irradiation ultraviolet light. As a result, negative ion-enriched air 9 that is cleaner than class 1 and from which gaseous pollutants are removed is obtained. (2) FIG. 7 shows that the adsorbent (activated carbon and ion exchange fiber) 20 is installed in the coarse filter section 3 of FIG. Basic gas such as ammonia and amine in clean room air by the adsorbent 20 (mainly collected by ion exchange fiber)
Acid gases such as sulfur dioxide, hydrogen chloride and hydrogen fluoride (mainly collected by activated carbon) are removed. Thereby, the negative ion-enriched air 9 which is cleaner than class 1 and from which the gaseous pollutants are removed is obtained.

Example 5 The air purifier 1 having the structure shown in FIG. 1 was installed in a room of 12 m ³ , and the photoelectron emission material was irradiated with ultraviolet light under an electric field to examine the negative ion concentration and the particle concentration in the room. In addition, in order to examine the effectiveness of negative ions, the generated air was exposed to strawberries and freshness retention was examined. Size of air purifier and air volume; 30 × 30 × 60cm,
0.5 m ³ / min, ultraviolet lamp; germicidal lamp (main wavelength: 254 nm), photoelectron emission material; germicidal lamp with Au enriched by sputtering method, electrode in particle collecting part (A); SUS Two meshes (20 mesh and 10 mesh) having different meshes are superimposed, electric field: 1.5 KV / cm, electrode in negative ion generating part (B); flat SUS plate, electric field: 30 V / cm, negative Ion concentration meter; Ion tester (0.4 cm ² /
VS or higher electric mobility), particle concentration meter; dust meter,

Results (1) Negative ion concentration and particle concentration The results are shown in Table 1.

[Table 1]

(Comparative Example) As a comparison with Example 5, in Example 5, the particle collecting part (A) and the negative ion generating part (B)
Of the same electric field (1.5 KV / cm or 30 V)
/ Cm) was set and examined in the same manner. Table 2 shows the results.

[Table 2]

(2) Preservation of Freshness of Strawberries As a freshness preserving effect, the number of days at which mold generation is observed at 5 ° C. was examined. Table 3 shows the results. The comparative example in Table 3 is a case where the electric field of the above electrode is 1.5 KV / cm.

[Table 3] The effectiveness of the negative ion-rich bacteria-treated air obtained by the present air purifier was examined by spraying negative ion air onto an agar medium, thereby cultivating various bacteria, and comparing with the case where no air was blown. No colonies were formed on the sprayed agar medium, but 1 colony was formed on the unsprayed agar medium.
5/10 cm ^{2 were} produced.

Embodiment 6 As shown in FIGS. 3 and 4, a photocatalyst and an adsorbent are respectively added to the air purifier having the structure shown in FIG. 1 of Embodiment 5 (installed in a 12 m ³ room as in Embodiment 5). Driving. In the test, tobacco smoke was generated indoors, and their deodorizing performance, hydrocarbon removing performance, and ammonia removing performance were examined. Photocatalyst; Quartz glass plate coated with TiO ₂ by sol-gel method; Adsorbent; Combination of activated carbon fiber and ion exchange fiber produced as follows; Anion exchange fiber; Fibrous polypropylene with electron beam 20 Mrad in nitrogen Irradiated, then immersed in a solution containing 60% and 40% of hydroxystyrene monomer and isoprene, respectively, and heated to a temperature of 35 ° C. to perform a graft polymerization reaction. After the reaction, quaternary amination was performed to obtain an anion exchange fiber. Odor concentration; Measured by the three-point comparison odor bag method; Hydrocarbon concentration; Non-methane hydrocarbon concentration measured by the GC method; Ammonia concentration; Measured by the chemiluminescence method;

Results The results are shown in Table 4.

[Table 4]

[0051]

According to the present invention, the following effects can be obtained. (1) By separating the electric field electrode into two parts, one for particle removal and the other for negative ion generation, it is possible to obtain negative ion-free air (clean, clean negative ions) from which particulate matter has been removed. Was done. The dust-removed clean negative ion-enriched gas was obtained by only one set (one set) of the photoelectron emission material, the ultraviolet and / or radiation source, and the electric field electrode. That is, the size of the apparatus was reduced, and the apparatus was compact having both functions of dust removal and negative ion generation. In addition, the downsizing has facilitated maintenance and management of the equipment such as maintenance and inspection. As described above, by installing a photocatalyst and / or an adsorbent, gaseous pollutants were also simultaneously removed by a compact apparatus. As a result, the applicable range (the type of device) has been expanded.

(2) From the above, the practicality of the next field utilizing negative ions has been improved. (A) The field of creating electrically stable spaces. (B) The field of creating a comfortable working space for a living body that does not impair the metabolic and physiological functions of the living body. (C) Fields that create amenities and a comfortable air environment. (D) The field of maintaining the freshness of food and preventing the growth of fungi.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a negative ion generator (air purifier) of the present invention.

FIG. 2 is an explanatory diagram showing air purification in a hospital room.

FIG. 3 is a sectional view showing another example of the negative ion generator (air purifier) of the present invention.

FIG. 4 is a sectional view showing another example of the negative ion generator (air purifier) of the present invention.

FIG. 5 is a cross-sectional configuration diagram of a transfer device provided with an example of the negative ion generator (air purifier) of the present invention.

FIG. 6 is a cross-sectional configuration diagram of a transfer device provided with another example of the negative ion generator (air purifier) of the present invention.

FIG. 7 is a cross-sectional configuration diagram of a transfer device provided with another example of the negative ion generator (air purifier) of the present invention.

FIG. 8 is a cross-sectional configuration diagram of a known negative ion generator.

[Explanation of symbols]

1: negative ion generator (air purifier), 2: fan,
3: Coarse filter, 4-1 and 4-2: Photoemission material, 5:
UV lamps, 6-1 and 6-2: electrodes, 8: contaminated air,
9: clean air, 10: hospital room, 11: particulate matter, 12:
Sick person, 13: ultraviolet irradiation window, 14-1, 14-2: photoelectron, 15: charged particle, 16: trapped particle, 17: bed,
18: Futon, 19: Photocatalyst, 20: Adsorbent, 21: Conveying device, 22: Reflective surface, 23: Quartz glass window, 24: Glass substrate, A: Charging / collecting unit, B: Negative ion generating unit,
C: clean space, D: before static elimination, E: after static elimination

Claims (4)

[Claims] In a method for generating negative ions, an electric field is formed between a photoelectron emitting material and an electric field electrode in a space, and the photoelectron emitting material is irradiated with ultraviolet rays and / or radiation under the electric field.
A method for generating negative ions, wherein two different electric fields for cleaning by particle removal and generating negative ions are formed between the photoelectron emitting material and the electric field electrode. 2. The method for generating negative ions according to claim 1, wherein said space is purified by purifying a gas by installing a photocatalyst and / or an adsorbent. 3. A negative ion generator having a photoelectron emitting material, an electrode for an electric field, and an irradiation source for irradiating the photoelectron emitting material with ultraviolet rays and / or radiation in a space, wherein the photoelectron emitting material and the electrode for an electric field are provided. Is an apparatus for generating negative ions, comprising two parts which form different electric fields for cleaning by particle removal and for generating negative ions. 4. The negative ion generator according to claim 3, wherein a photocatalyst and / or an adsorbent for purifying the negative ion generating gas is installed in the space.