KR20200032387A - Air cleaner using low temperature plasma - Google Patents

Abstract

According to the present invention, an air purifier using low temperature plasma comprises: a dielectric barrier discharge filter; and a functional filter in which a metal complex type polymeric membrane and a metal complex type carbon pore membrane are bonded to each other. Accordingly, the air purifier is excellent in removal of molds, bacteria, fine dust, volatile organic compounds, and odors, and can prevent the risk of secondary contamination by removing unreacted ozone and oxide produced after incineration.

Description

Air cleaner using low temperature plasma {Air cleaner using low temperature plasma}

The present invention relates to an air purifier using a low temperature plasma, and more particularly, to an air purifier including a dielectric barrier discharge filter and a functional filter.

Recently, as fine dust has become a social issue, and clean air has emerged as an essential condition for improving the quality of life and maintaining health, interest in indoor air quality management has increased. Accordingly, public facilities such as subways, gymnasiums, department stores, etc. Korean air quality management is emerging. Modern people spend most of their time in various indoor environments, and indoors are closed, unlike outdoor environments, so there is little air distribution to the outside. Recently, the indoor space is closed to the outside to control economical temperature and humidity. Since it is maintained, many people are exposed to various harmful substances such as dust, volatile organic compounds (VOCs), carbon monoxide, and cigarette smoke mixed in indoor air. Therefore, the demand for air cleaners is increasing as an alternative for maintaining a pleasant environment.

Air purifiers can be divided into mechanical, electric, and complex types depending on the method of removing pollutants from the air. Depending on the application principle, mechanical type is dry (filter type) and wet, electric type is electrostatic dust collection type, anion type, plasma type, and It can be divided into UV photocatalytic type, and the complex type is a combination of mechanical and electrical functions. Among them, a plasma-type air purifier removes harmful substances by applying a voltage to air molecules to create a plasma state. At this time, high-energy electrons or ions, and oxygen, nitrogen in the gas, and ozone (O) by collision with these electrons ₃ ) Active species such as and oxides are generated, and these reactive active species have high reactivity, exhibiting a sterilizing effect that promotes decomposition of harmful substances in the air, and removes volatile organic compounds and odors. In addition, high-energy electrons can destroy chemical bonds in organic compounds in the form of direct electron collisions, and ozone has a strong oxidizing effect. These plasmas have a much higher sterilizing power compared to ultraviolet rays and have no risk of damage, and the ions generated in the plasma have the advantage of not generating residual pollutants because they are reduced to oxygen in a short time with strong oxidizing ability, but ozone generated at this time has an oxidizing power Because it is strong and irritates the eyes and is poorly soluble in water, it can easily reach the depths to cause wastewater species, pulmonary hemorrhage, etc., and act on DNA or RNA to cause changes in genetic factors. do.

As a solution to the above problems, a complex form in which a plasma and a filter are used in combination has been developed, and a chemical adsorption filter that removes chemically harmful substances is frequently used as a filter. As a typical chemical adsorption filter, an activated carbon-based impregnated adsorption filter is mainly used. However, in order to remove harmful substances, the impregnated substances generate salts by acid-alkali neutralization reaction during purification, and the longer the purification time, the more salts are generated. Since the pores of the filter are blocked, there is a problem in that the function of the filter is deteriorated due to a pressure loss of the fluid. In addition, the impregnated acidic and alkaline substances have high volatility, and there is a possibility of secondary contamination by volatilization. For example, Korean Patent Registration No. 10-0358262 discloses a chemical adsorption filter for ozone decomposition using activated carbon, but the filter still has a problem of dust generation or secondary pollution due to impact and abrasion. Accordingly, there is a need to develop an air purifier capable of improving the risk of dust generation and secondary pollution, which are disadvantages of ozone generation and chemical adsorption filters due to plasma.

KR 10-0358262 B

The present invention has been devised to solve the problems of the prior art as described above, using a plasma, mold, bacteria, fine dust, volatile organic compounds (VOCs), dielectric barrier discharge (DBD) filter to incinerate odor and unreacted It is an object to provide an air purifier comprising a functional filter for removing ozone and oxides produced after incineration.

The present invention to achieve the above object,

As an air purifier having a function of removing mold, bacteria, fine dust, volatile organic compounds (VOCs) and odors, the air purifier includes a housing; A fan formed in the housing to suck air; A dielectric barrier discharge filter that purifies air introduced by the fan through low temperature plasma discharge; A functional filter for removing ozone and oxide contained in air passing through the dielectric barrier discharge filter; Included in the outlet is formed in the housing to discharge the air passing through the functional filter.

The air purifier includes a plasma power supply connected to a dielectric barrier discharge filter, and the plasma power supply includes a power supply for supplying power; A voltmeter for applying a high voltage; And a voltage-regulating transformer.

In the dielectric barrier discharge filter, a plurality of conductive electrodes coated with a dielectric are disposed in close contact with each other, and the functional filter is characterized in that a metal complex type polymer film and a metal complex type carbon pore film are adhered to each other.

The metal complex-type polymer film is characterized in that it contains one or more functional groups selected from the group consisting of carboxyl groups, sulfonic acid groups, and phosphoric acid groups on the surface of the polymer film, and is characterized in that metal is supported in a complex form on the polymer film containing the functional groups.

The metal-composite-type carbon porous membrane includes one or more functional groups selected from the group consisting of carboxyl groups, sulfonic acid groups, and phosphoric acid groups on the surface of the carbon porous membrane, and is characterized in that metal is supported in a complex form on the carbon porous membrane containing the functional groups. do.

The metal is at least one selected from the group consisting of silver, copper, gold, zinc and platinum, and the size of the metal is 1 to 100 nm.

The air purifier using the low temperature plasma of the present invention has excellent removal effect on various pollutants contained in indoor air such as mold, bacteria, fine dust, volatile organic compounds, and odors by using low temperature plasma discharge. It can be used in all fields. In addition, by removing unreacted ozone generated during air purification by low-temperature plasma and oxides generated after incineration with a functional filter, the risk of ozone can be eliminated and damage to secondary pollution can be prevented.

1 is a graph for evaluating adsorption performance of volatile organic compounds according to an embodiment of the present invention.
2 is a (a) tobacco smoke component separation graph and (b) tobacco smoke deodorization performance evaluation graph according to an embodiment of the present invention.
3 is a photograph and a SEM image of a functional filter according to an embodiment of the present invention. (a) Photo before test, (b) Photo after removal of volatile organic compounds, (c) Photo after removal of cigarette smoke, (d) SEM image before test, (e) SEM image after removal of volatile organic compounds, (f) Cigarette smoke SEM image after removal.
Figure 4 is a (a) front view, (b) rear view, (c) side view of the air purifier according to the present invention.
5 is a conceptual diagram showing an air purifier according to the present invention.

Hereinafter, an air purifier using a low-temperature plasma according to the present invention will be described in detail.

The present invention is an air purifier having a function of removing mold, bacteria, fine dust, volatile organic compounds (VOCs) and odors, the housing; A fan formed in the housing to suck air; A dielectric barrier discharge filter that purifies air introduced by the fan through low temperature plasma discharge; A functional filter for removing ozone and oxide contained in air passing through the dielectric barrier discharge filter; It provides an air purifier comprising a; formed in the housing to discharge the air passing through the functional filter.

The dielectric barrier discharge (DBD) is one of low temperature plasmas, and is generated by applying an alternating current (AC) or pulsed high voltage to a conductor electrode surrounded by a dielectric at regular intervals. When a voltage is applied, electrons accumulated in the dielectric barrier are released due to a build-up phenomenon surrounding the electrode, and a large number of micro discharges are formed between the electrodes, and high concentration electrons forming a micro discharge. By this, radicals and ions are generated between the electrodes.

In the dielectric barrier discharge filter, a plurality of conductive electrodes coated with a dielectric are disposed in close contact with each other, and the air cleaner includes a plasma power supply connected to the dielectric barrier discharge filter, and the plasma power supply supplies power. A power supply unit for supplying; A voltmeter for applying a high voltage; And a voltage-regulating transformer.

The functional filter is preferably a metal complex-type polymer film and a metal complex-type carbon porous film are bonded.

The metal complex-type polymer film preferably contains one or more functional groups selected from the group consisting of carboxyl groups, sulfonic acid groups, and phosphoric acid groups on the surface of the polymer film, and the metal film in the form of a complex is supported on the polymer film containing the functional groups.

The polymer material of the polymer film may be at least one selected from the group consisting of polyethylene, polypropylene, polyurethane, polyethylene terephthalate, styrene-butadiene rubber and nitrile-butadiene rubber, and the price competitiveness, ease of handling, surface condition and material, etc. It is preferable to consider polyethylene and polypropylene.

The polymer membrane preferably has a porosity of 1 to 50%, and if the porosity is less than 1%, the air permeability falls, and if it exceeds 50%, the graft rate may drop. In addition, the thickness of the polymer film is preferably 1 to 5 mm, and if the thickness is less than 1 mm, uniform grafting is difficult, and if it exceeds 5 mm, workability may be deteriorated.

As described above, in consideration of porosity, thickness, material, use, and cost, the polymer film is preferably non-woven.

It is preferable that the metal-composite-type carbon porous film includes a functional group whose surface of the carbon porous film is modified by an electrochemical method, and that the metal is supported in the form of a complex on the carbon porous film containing the functional group. The electrochemical method is a cyclic voltammetry method, and the functional group is preferably one or more selected from the group consisting of carboxyl groups, sulfonic acid groups and phosphoric acid groups. The metal may be used without limitation as long as it is a metal exhibiting antibacterial properties. For example, one or more selected from the group consisting of silver, copper, gold, zinc, and platinum may be used, and preferably silver or copper is used. It can be improved further. In addition, the size of the metal is preferably 1 to 100 nm, because it is easy to bond to the surface of the carbon pore film in the form of a complex when in the above range, because it can increase the antimicrobial effect.

When modifying the surface of the carbon porous membrane, it is preferable to further include a silane coupling agent, because it is possible to improve the bonding force between the carbon porous membrane and the metal complex by further including a silane coupling agent.

The pore size of the carbon pore film is 5 to 500 nm, and it is preferable that the error range is a uniform size of ± 10%, which increases the specific surface area of the carbon pore film than conventional filters, thereby improving the adsorption / removal efficiency of volatile organic compounds. It is to order.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited thereto.

Example  1. Functional filter manufacturing

One. Metal complex type  Polymer membrane production ( Example  1-1)

1) Preparation of diazonium salt having carboxyl group

Under an ice bath, add 1 liter of 0.2 M HCl to a 2 liter reaction vessel, stir at 300 rpm, add 27.428 g of 4-Aminobenzoic acid, and 0.02 M using a 20 ml / min peristaltic pump. 250 ml of NaNO ₂ was added slowly in small portions. Then, the mixture was stirred at 300 rpm for 2 hours to prepare a diazonium salt having a carboxy group.

2) Preparation of functional group-modified polymer membrane

A polyethylene nonwoven fabric having a porosity of 5 cm × 5 cm × 0.3 cm with a porosity of 20% (daesan product, polyethylene) was washed with MeOH for 10 minutes and then dried at 70 ° C. for 3 hours using a vacuum oven.

Separately, a 70 ° C. water bath was prepared on a hot plate, and after dipping a 500 mL flask in the constant temperature bath, 100 mL of a diazonium salt having a carboxy group prepared above was added. Here, the dried polyethylene nonwoven fabric was added, sufficiently moistened, and stirred. Thereafter, 0.03 mol of potassium sulfate was added to 1 mol of the diazonium salt having a carboxyl group, followed by stirring at 500 rpm for 1 hour to perform graft polymerization. After the reaction was completed, the nonwoven fabric was taken out, washed with distilled water, and dried at 70 ° C for 3 hours using a vacuum oven.

3) Preparation of metal complex type polymer membrane

After adding 250 ml of a 0.2 mM silver nitrate solution to a flat bottom flask, the functional group-modified polymer membrane prepared above was added and stirred for 1 hour. Thereafter, the polymer membrane was taken out, washed with distilled water, and dried at 70 ° C. for 3 hours using a vacuum oven.

2. Metal complex type Carbon Porous Film  Produce ( Example  1-2)

1) Preparation of nanoparticles by sol-gel synthesis

After adding and stirring 12 ml of 99% Cyclohexane 300 and 99% N-Hexyl alcohol (Haxanol) in a 1 liter reactor, after stirring, tergitol NP- so that reverse micelles can be formed in a uniform size 38 ml of 9 (Tergitol NP-9) was added and stirred sufficiently. When the inside of the reactor becomes transparent after adding 15 ml of tertiary distilled water and 34 ml of 28% ammonium hydroxide to allow the silica ions to hydrolyze in the reactor, 98% TEOS (Tetraethyl orthosilicate) is used as a silicon alkoxide unit precursor. 20 ml was added. The cyclohexane solvent in the reactor was removed with a rotary vacuum evaporator to prepare a colloidal silica solution, and then 200 mL of 99.9% ethyl alcohol (Absolute ethanol) was added and stirred sufficiently to disperse well. Thereafter, centrifugation was performed at about 5000 to 6000 rpm with a centrifuge to separate ethanol and colloidal silica, and the separated ethanol solution was discarded and dried at 100 ° C. in an oven to obtain silica powder having an average particle diameter of 50 nm. Did. At this time, the error range of the average particle diameter of the silica powder is ± 50%. The obtained silica powder was separated from the silica powder having an average particle diameter of 50 nm using a field flow fractionation (FFF) device, wherein the error range of the average particle diameter of the silica powder was ± 10%.

2) Preparation of porous carbon porous membrane

The separated silica powder was sintered to prepare a nanoparticle mold in which pores of a desired size were arranged, and the sintering was performed by applying a force of 10 ton at 130 ° C for 10 minutes with a hydraulic press. The nanoparticle mold and carbon medium (0.01 M PVC aqueous solution) prepared above were put into a Teflon beaker and stirred while heating to 100 ° C., and the viscosity of the carbon medium during stirring was measured with a Brookfield viscometer to obtain a viscosity of 30,000 mPa · s ( at No.4 Spindle), put it in an oven at 160 ℃ to completely dry the PVC aqueous solution. The nanoparticle mold taken out of the oven was washed with distilled water to remove the PVC on the surface, placed in a quartz tube, and fired in a tube furnace. After making the furnace completely into an argon atmosphere, the temperature of the argon gas was gradually flowed out gradually. It was raised to 1000 ° C and fired for 5 hours to prepare a silica nanoparticle template / carbon composite. In order to remove the silica nanoparticle template from the silica nanoparticle template / carbon composite, the silica nanoparticle template / carbon composite is added to a Teflon bottle, and an excess of 48% hydrofluoric acid is added to the Teflon bottle as a shaker. Shake for 10 hours. The hydrofluoric acid was filtered using a cellulose nitrate membrane filter, and the remaining hydrofluoric acid was sufficiently washed with distilled water and dried to prepare a porous carbon porous membrane.

3) Manufacture of metal complex type carbon porous membrane

In order to activate the surface of the prepared porous carbon porous membrane, acrylic acid (Acrylic acid anhydrous, contains 180-200 ppm MEHQ as inhibitor, 99%, Sigma-Aldrich) and silver nitrate were circulated in the porous carbon porous membrane for 6 hours. After reaction, it was washed with distilled water.

Comparative example  One

After adding 250 ml of 0.2 mM silver nitrate solution to the trough bottom flask, a polyethylene nonwoven fabric (polyacid, polyethylene) having a porosity of 20% of 5 cm × 5 cm × 0.3 cm was added and stirred for 1 hour. Thereafter, the polyethylene nonwoven fabric was taken out, washed with distilled water, and dried at 70 ° C. for 3 hours using a vacuum oven.

Comparative example  2

Commercial air purification filter (Yuhan Kimberly)

Experimental example  One. Volatile organic compounds  Adsorption performance evaluation

The adsorption performance of volatile organic compounds was evaluated on hexane, toluene, and chloroform, and each test gas having a concentration of 800 ppb was passed through the prepared functional filter at a cross-sectional flow rate of 0.8 m / s, and the adsorption amount over time was measured. It was measured. As a result, as shown in Table 1 below, hexane was reduced by 18.52% compared to 0 minutes after 30 minutes, and 11.11% compared to 0 minutes after 60 minutes, and all was adsorbed and removed 100% after 90 minutes. Toluene decreased 47.86% compared to 0 minutes after 30 minutes, and 71.43% compared to 0 minutes after 60 minutes, and all was adsorbed and removed 100% after 180 minutes. Chloroform decreased 96.81% compared to 0 minutes after 30 minutes, 56.31% compared to 0 minutes after 60 minutes, and 100% compared to 0 minutes after 90 minutes, and all was adsorbed and removed 100% after 180 minutes.

Concentration (%) 0 minutes 30 minutes 60 minutes 90 minutes 120 minutes 150 minutes 180 minutes 210 minutes Base 0 0 0 0 0 0 0 0 Hexane 100 81.48 88.89 0 0 0 0 0 toluene 100 52.14 28.57 107.14 45.00 100.00 0 0 Chloroform 100 3.19 43.69 0 8.03 8.40 0 0

Experimental example  2. Cigarette smoke deodorization performance evaluation

The deodorizing performance of the functional filter was evaluated for four unknown components detected in cigarette smoke. Referring to Table 2 below, component A was deodorized 16% compared to 0 minutes after 10 minutes, 40% compared to 0 minutes after 35 minutes, and 55% compared to 0 minutes after 50 minutes, and component B was 32% compared to 0 minutes after 10 minutes. , It showed deodorization rate of 50% compared to 0 minutes after 35 minutes, and 55% compared to 0 minutes after 50 minutes. In addition, component C was deodorized at 36% compared to 0 minutes after 10 minutes, 50% compared to 0 minutes after 35 minutes, and 55% compared to 0 minutes after 50 minutes, component D was 40% compared to 0 minutes after 10 minutes, and 0 minutes after 35 minutes. The deodorization rate was 63% compared to 65% compared to 0 minutes after 50 minutes. From the above results, it was confirmed that the functional filter according to the present invention showed a deodorizing effect of 55% or more of cigarette smoke within 1 hour.

Concentration (%) 0 minutes 10 minutes 35 minutes 50 minutes Base 0 0 0 0 A 100 84 60 45 B 100 68 50 45 C 100 64 50 45 D 100 60 37 35

Experimental example  3. Specific surface area  Measure

The specific surface area is shown in Table 3 below by measuring the BET of the filters prepared in Examples and Comparative Examples. As shown in Table 3 below, it was confirmed that the specific surface area of the present invention was superior to Comparative Example 1 in which graft polymerization was not performed and a commercially available filter for air purification.

Specific surface area (m ² / g) Example 1-1 60 Example 1-2 422 Comparative Example 1 31 Comparative Example 2 32

Experimental example  4. Antibacterial activity evaluation

To evaluate the antimicrobial activity, the microorganisms in the air were collected on the filter surfaces of Examples and Comparative Examples, the filter was put into a liquid medium, shaken out, and the liquid medium was incubated for 64 hours, and the absorbance of the liquid medium was measured. The proliferation was confirmed. As shown in Table 4, it was confirmed that Example 1 of the present invention has better antibacterial activity than Comparative Examples 1 and 2.

Absorbance (660 nm) Example 1 0.105 Comparative Example 1 0.381 Comparative Example 2 0.520

The above description is merely illustrative of the present invention, and those skilled in the art to which the present invention pertains will be capable of various modifications without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed herein are not intended to limit the present invention, but to explain the present invention, and the spirit and scope of the present invention are not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technologies within the equivalent range should be interpreted as being included in the scope of the present invention.

Claims (8)

As an air purifier with a function of removing mold, bacteria, fine dust, volatile organic compounds (VOCs) and odors,
The air purifier housing;
A fan formed in the housing to suck air;
A dielectric barrier discharge filter that purifies air introduced by the fan through low temperature plasma discharge;
A functional filter for removing ozone and oxide contained in air passing through the dielectric barrier discharge filter;
An air purifier comprising; a discharge port formed in the housing to discharge air passing through the functional filter.
The air purifier of claim 1, wherein the dielectric barrier discharge filter is disposed in close contact with a plurality of conductive electrodes coated with a dielectric material.
The air purifier of claim 1, further comprising a plasma power supply connected to the dielectric barrier discharge filter.
According to claim 3, The plasma power supply unit Power supply for supplying power; A voltmeter for applying a high voltage; And a transformer that regulates the voltage.
The air purifier according to claim 1, wherein the functional filter has a metal complex type polymer film and a metal complex type carbon pore film adhered to each other.
The method of claim 5, wherein the metal complex-type polymer film comprises one or more functional groups selected from the group consisting of carboxyl groups, sulfonic acid groups and phosphoric acid groups on the surface of the polymer film, and is characterized in that metal is supported in a complex form on the polymer film containing the functional groups. Air purifier made with
The method of claim 5, wherein the metal complex-type carbon porous film comprises at least one functional group selected from the group consisting of carboxyl groups, sulfonic acid groups and phosphoric acid groups on the surface of the carbon porous film, and the metal is complexed to the carbon porous film containing the functional group. Air purifier characterized by being loaded with
The air purifier according to claim 6, wherein the metal is at least one selected from the group consisting of silver, copper, gold, zinc and platinum, and the size of the metal is 1 to 100 nm.

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