KR102876953B1 - Sterilizer for air purification - Google Patents

Abstract

The present invention relates to a hybrid catalytic filter that generates hydroxyl radicals and an air purifying sterilizer comprising the same. The sterilizer manufactured by the present invention enables environmentally friendly and safe air sterilization because the hybrid catalytic filter generates radicals, enables radical reactions regardless of pH without a neutralizer, and decomposes into carbon dioxide and water after the reaction. Using the manufactured sterilizer, various indoor pollutants, including dust, volatile organic compounds, viruses, and bacteria contained in the air, can be effectively removed, thereby releasing more hygienic and clean air. In addition, the catalytic filter does not generate ozone and has a simple structure, making it economical. Furthermore, it can be used as a filter for air conditioners, air conditioners, dehumidifiers, automobile air conditioners and air filters, electric vacuum cleaners, and clean rooms in semiconductor or biotechnology laboratories.

Description

STERILIZER FOR AIR PURIFICATION

The present invention relates to a hybrid catalyst filter that generates hydroxyl radicals and an air purifying sterilizer including the same.

A sterilizer is a machine that filters and removes or sterilizes airborne microorganisms, viruses, mold, and dust. Primarily used indoors, it improves air quality by removing harmful substances from the air and maintains a sanitary environment in accommodations, medical facilities, and the food and beverage industry. The recent rise in air pollution has led to a surge in demand for air purifiers and sterilizers, driven by the desire to breathe fresh air. This demand is a natural phenomenon for modern people seeking well-being.

Sterilizers operate on a similar principle to air purifiers. Typically, a sterilizer's filter absorbs oxidizing substances (malodorous substances) in the air to filter and sterilize the air. Conventional filter methods for air purification have the advantage of being highly effective at removing fine dust and filtering out a significant portion of bacteria attached to particles. However, they are difficult to sterilize the bacteria themselves, and there have been limitations in achieving strict standards of sterilization efficiency. As the need for sterilization of bacteria and other airborne pathogens increases, the need for air sterilization devices that can not only remove fine particles but also sterilize bacteria and viruses is also growing.

Meanwhile, the hydroxyl radical (OH·) possesses a much stronger oxidizing power than ozone or chlorine, and has been consistently used for sterilization and purification of soil and water contamination. In particular, the Fenton reaction, in which transition metal ions such as iron or copper react with hydrogen peroxide to produce hydroxyl radicals, is one of the major hydroxyl radical-generating reactions. Hydroxyl radicals act as oxidizing agents, starting chain reactions that oxidize other molecules. This reaction allows hydroxyl radicals to decompose organic matter and have sterilizing properties, making them useful in wastewater purification and other applications.

Because hydroxyl radicals are chemically highly reactive oxidizing agents, most organic matter is oxidized upon contact with hydroxyl radicals. The number of available reaction sites for the removal, mineralization, and/or oxidation of bacteria, mold, fungi, spores, mycotoxins, viruses, allergens, and other similar organic microorganisms or pathogens, and VOCs can be dramatically increased by hydroxyl radicals. By dramatically increasing the number of available reaction sites and increasing the number of oxidation reactions that occur, the air treatment efficiency can be significantly improved by the removal, mineralization, and/or oxidation of bacteria, mold, fungi, spores, mycotoxins, viruses, allergens, and other similar organic microorganisms or pathogens, and VOCs.

Meanwhile, existing air purification systems utilizing hydroxyl radicals primarily utilize plasma, UV, and ozone to generate hydroxyl radicals. These existing methods face challenges in safely and effectively delivering hydroxyl radicals to indoor environments, and are also complex and uneconomical.

In order to solve the above problems, the applicant, while researching an air purification method using hydroxyl radicals, developed a sterilizer including a catalytic filter that decomposes hydrogen peroxide to generate hydroxyl radicals, and completed the present invention.

The purpose of the present invention is to provide a hybrid catalyst filter and an air purification sterilizer including the same.

In order to achieve the above object, the present invention provides an air purifying sterilizer comprising a catalytic filter that generates hydroxyl radicals, wherein the catalytic filter comprises an iron compound, a copper salt, and a chelating agent.

In addition, the present invention provides a filter for a sterilizer, characterized in that it comprises an iron compound, a copper salt, and a chelating agent, and generates hydroxyl radicals.

In addition, the present invention comprises the steps of (a) chelating an iron compound with a chelating agent;

(b) a step of chelating a copper salt with a chelating agent;

(c) a step of preparing a turbid solution by mixing the chelated iron compound and the chelated copper salt;

(d) a step of immersing the prepared turbidity in a carbonaceous material; and

(e) A method for manufacturing a filter for a sterilizer is provided, comprising the step of drying the carbonaceous material immersed in the above turbid solution at a temperature of 80°C to 100°C.

The sterilizer manufactured by the present invention is capable of environmentally friendly and safe air sterilization because the hybrid catalyst filter generates radicals, enables radical reactions regardless of pH without a neutralizer, and decomposes into carbon dioxide and water after the reaction. Using the manufactured sterilizer, various indoor pollutants including dust, volatile organic compounds, viruses, and bacteria contained in the air can be effectively removed, thereby emitting more hygienic and clean air. In addition, the catalytic filter does not generate ozone and has a simple structure, making it economical. Furthermore, it can be used as a filter for air conditioners, air conditioners, dehumidifiers, automobile air conditioners and air filters, electric vacuum cleaners, and clean rooms in semiconductor or biotechnology laboratories.

Figure 1 is a diagram showing a catalyst filter manufactured according to the present invention.
Figure 2 is a diagram showing a sterilizer manufactured according to the present invention.
Figure 3 is a schematic diagram showing an air sterilization system of a sterilizer manufactured according to the present invention.
Figure 4 is a diagram showing a manufacturing process of a catalyst filter that generates hydroxyl radicals according to the present invention.
Figures 5 and 6 are diagrams showing the air sterilization test results conducted by the Korea Testing Laboratory for Industrial Technology for the sterilizer according to the present invention.

The present invention relates to a hybrid catalyst filter that generates hydroxyl radicals and an air purifying sterilizer including the same.

The present invention will be described in detail below.

In addition, the terminology used in this specification is a term used to describe the present invention, and may vary depending on the intention of the user or operator, or the customs of the field to which the present invention belongs. Therefore, the definition of these terms should be determined based on the contents throughout this specification. Throughout this specification, when a part is said to "include" a certain component, this does not mean that other components are excluded, but rather that other components may be included, unless specifically stated otherwise. In addition, although preferred methods or samples are described in this specification, similar or equivalent methods are also included within the scope of the present invention.

Specifically, the present invention comprises a hybrid catalyst filter that decomposes hydrogen peroxide to generate hydroxyl radicals, wherein the hybrid catalyst filter comprises a catalyst, and the catalyst comprises an iron compound, a copper salt, and a chelating agent.

The above-mentioned hydroxyl radical is a type of reactive oxygen species generated within the body. It is created from hydrogen peroxide in the presence of iron or copper metal chelates reduced by electron donors such as superoxide radicals or ascorbic acid. Because hydroxyl radicals are chemically highly reactive oxidizing agents, most organic substances are oxidized upon contact with them, and they are also used as purification agents that oxidize organic pollutants in groundwater and soil to produce carbon dioxide and water.

The above hydroxyl radical can be generated by the Fenton oxidation reaction. The Fenton oxidation reaction is as follows.

Equation (1): Fe(II) + H ₂ O ₂ → Fe(III) + OH· + OH-

Formula (2): Fe(III) + H ₂ O ₂ → Fe(II) + HO ₂ · + H+

Equation (3): RH + OH· or HO ₂ · → oxidized product

As shown in the above equation (1), Fe(II) and _H2O2 react to form hydroxyl radicals (OH·, _redox potential ^E0 is 2.80 V) and Fe(III), and iron (Fe(II)) with a divalent valence reacts with hydrogen peroxide ( _H2O2 ) to be oxidized, forming active _hydroxyl radicals (OH·) with a stronger oxidizing power than ozone ( _O3 ). The hydroxyl radicals (OH·) remove malodorous substances or harmful organic substances, and divalent iron and hydrogen peroxide can be said to be the main reaction sources.

Next, as shown in the above equation (2), the generated Fe(III) can be reduced by reaction with an excess of hydrogen peroxide to generate Fe(II) and hydroperoxyl radicals (HO2·). The hydroperoxyl radicals ( _HO2 ·) can also be used to reduce malodorous substances, hazardous organic substances, or difficult-to-decompose pollutants. Once these radical species (OH· or _HO2 ·) are formed, they react with organic pollutants (RH) as shown in equation (3). This Fenton oxidation reaction is affected by pH, and the reaction can proceed only when the pH is maintained at 3 to 4.

The catalytic filter according to the present invention decomposes hydrogen peroxide to generate hydroxyl radicals. When hydrogen peroxide is not sprayed, the filter itself releases hydroxyl radicals through oxygen in the air. When hydrogen peroxide is sprayed, the filter decomposes hydrogen peroxide to generate hydroxyl radicals. A simplified reaction equation of chelated Fenton when hydrogen peroxide is sprayed is as follows.

Equation (4): Fe(II) + L ↔ Fe(III)-L

Equation (5): Fe(III) + L ↔ Fe(III)-L

Equation (6): Fe(II)-L + H ₂ O ₂ → Fe(III)-L + OH· + OH ^-

Formula (7): Fe(III)-L + H ₂ O ₂ → Fe(II)-L + H ⁺ + HO ₂ ·

The Fe-L complex formed in the above equations (4) and (5) decomposes H ₂ O ₂ to generate reactive oxygen species (OH· or HO ₂ ·) as shown in equations (6) and (7). The generated hydroxyl radicals (OH·) can cause a chain oxidation reaction with organic matter.

A simplified reaction equation for chelated Fenton when hydrogen peroxide is not injected is as follows:

Equation (8): Fe(II)-L + O ₂ → Fe(III)-L + O ₂ ^- ·

Equation (9): Fe(II)-L + O ₂ ^- · → Fe(III)-L + O ₂ ^2-

Equation (10): 2H ₂ O + O ₂ ^2- → H ₂ O ₂ + 2OH ^-

Equation (11): Fe(II)-L + H ₂ O ₂ → Fe(III) + OH· + OH ^-

As described above, in the oxidation process of iron chelate by oxygen, superoxide radical ions (O ₂ ^- ·) and hydrogen peroxide, similar to the Fenton oxidation reaction, are generated, and this hydrogen peroxide is then converted into hydroxyl radicals (OH ·). In addition, hydroxyl radicals (OH ·) and hydrogen peroxide can oxidize most organometals.

The organic matter of the above reaction can ultimately be decomposed into water (H ₂ O) and carbon dioxide (CO ₂ ).

As described above, the hydroxyl radical (OH·) generated in the catalyst filter of the present invention oxidizes and decomposes polluting organic compounds, converts them into water (H ₂ O) and carbon dioxide (CO ₂ ) that are harmless to the human body, removes odors, sterilizes germs, etc., and oxidizes and decomposes sterilized germs, etc., thereby enabling environmentally friendly and safe air purification.

As the sprayed hydrogen peroxide is absorbed by the filter, radicals are generated, enabling immediate sterilization and deodorization. By supporting the iron catalyst required for this radical reaction on a carrier, efficient radical generation and even catalyst distribution are possible.

Furthermore, according to the standard reduction potentials Fe ³⁺ /Fe ²⁺ (E ⁰ = 0.77 V) and Cu ²⁺ /Cu ⁺ (E ⁰ = 0.17 V), the process of reducing Fe ³⁺ by Cu ⁺ is thermodynamically feasible by the following reaction (12).

Equation (12): Fe ³⁺ + Cu ⁺ → Fe ²⁺ + Cu ²⁺ , △E ⁰ = 0.6V

The above iron compound may be water-soluble, and is preferably ferrous chloride (FeCl ₂ ), ferrous chloride (FeCl ₃ ), or ferrous sulfate (FeSO ₄ ). It may be at least one selected from the group consisting of ferric sulfate (Fe ₂ (SO ₄ ) ₃ ), ferrous acetate, ferric formate, ferrous gluconate, ferric glycophosphate, ferric nitrate, ferric oxalate, ferric citrate, ferric orthophosphate, ferrous iodide, ferrous lactate, and catocene, and more preferably ferric chloride (FeCl ₃ ).

The above copper salt may preferably be at least one selected from the group consisting of copper sulfate, copper chloride, copper nitrate, copper citrate, copper malate, copper oxalate, cuprous sulfide, and Cu-EDTA.

The chelating agent is preferably one selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), trans-1,2-diaminocyclohexane-N,N,N,N'-tetraacetic acid monohydrate (CyDTA), dihydroxyethylglycine (DHEG), ethylenediaminetetrakis(methylenephosphonic acid) (EDTPO), diethylenetriamine-N,N,N'N",N"-pentaacetic acid (DTPA), citric acid, diaminopropanoltetraacetic acid (EPTA-OH), ethylenediaminediacetic acid (EDDA), ethylenediamine-N,N'-bis(methylenephosphonic acid) 1/2 hydrate (EDDPO), 2-aminoethyl ethylene glycol tetraacetic acid (GEDTA), and hydroxyethylethylenediaminetriacetic acid (EDTA-OH), tartaric acid, citric acid, and oxalic acid. It may be, more preferably, ethylenediaminetetraacetic acid (EDTA).

The above chelating agent forms chelates through a chelation reaction. Typically, a transition metal atom or ion binds to one or more ligands. If a ligand molecule contains multiple main atoms, it can simultaneously form coordinate bonds surrounding the central metal. These multidentate ligand metal complexes are called chelates, and chelate complexes are thermodynamically more stable than complexes composed of multiple monodentate ligands with similar structures.

In the present invention, the hydroxyl radical of the catalyst filter eliminates the need for initial acidification due to the presence of a chelating agent, so unlike conventional radical reactions that require a neutralizing agent during reaction, the radical reaction is possible regardless of pH, so no neutralizing agent is required.

The present invention may further include a HEPA filter, preferably a filter having an air purification efficiency of approximately 99.97%. The HEPA filter is positioned at the innermost part of the filter section, and the catalytic filter is positioned outside of the filter section.

In addition, the present invention may further include a pre-filter formed within the case of the sterilizer. The pre-filter filters large dust particles larger than a predetermined size contained in the outside air, and the HEPA filter filters fine dust particles smaller than a predetermined size contained in the outside air, and can remove particles smaller in size than the pre-filter. The HEPA filter has the functions of removing viruses, sterilizing, removing dust, removing cigarette smoke, removing smoke, removing mites, and removing pollen.

When a pre-filter and a HEPA filter are present, it is preferable that the catalytic filter sprayed with hydrogen peroxide be arranged in a stacked structure between the pre-filter and the HEPA filter.

The above hybrid catalyst filter can preferably be manufactured by immersing a catalyst in a carbonaceous material, and the carbonaceous material can preferably be at least one selected from the group consisting of charcoal, activated charcoal, activated carbon, bituminous coal, impregnated activated carbon, bone char, acid washed activated carbon, coconut shell based activated carbon, wood-based activated carbon, regenerated activated carbon, anthracite coal, zeolite mixed coal, virgin activated carbon, water-washed catalytic carbon, and charred vegetation.

The sterilizer of the present invention allows air to pass from one side to the other, and removes substances contained in the air passing through the filter unit by adsorbing them, while simultaneously sterilizing the air.

The operating flow of the sterilizer of the present invention having the above-described configuration is as follows.

First, when the user turns on the switch, a driving signal is applied to the motor, which drives the motor and rotates the blower fan. Accordingly, the rotation of the blower fan causes outside air to be sucked into the case through the air intake port. The sucked outside air passes through the hybrid catalytic filter, and deodorization and sterilization occur through radical reactions. Next, the outside air that has passed through the hybrid catalytic filter passes through the HEPA filter located inside, thereby filtering out fine dust particles smaller than a certain size contained in the outside air. This clean air is discharged back to the outside air through the air outlet, thereby sterilizing and purifying the indoor air.

In addition, the present invention provides a sterilizing filter comprising an iron compound, a copper salt, and a chelating agent. The sterilizing filter decomposes hydrogen peroxide to generate hydroxyl radicals. When hydrogen peroxide is not sprayed, the filter itself releases hydroxyl radicals through oxygen in the air, and when hydrogen peroxide is sprayed, the filter decomposes hydrogen peroxide to generate hydroxyl radicals. In other words, the filter is a hybrid catalytic filter that generates hydroxyl radicals regardless of whether hydrogen peroxide is sprayed.

When the hydrogen peroxide is sprayed, it is preferably sprayed by mist spraying or fumigation, and more preferably, it can be sprayed in granular form. The hydrogen peroxide is granulated by mixing a catalyst supported on a carrier, and the carrier can preferably be kaolin. When the hydrogen peroxide is sprayed, if the sensor module of the sterilizer determines that the contamination level is high, the hydrogen peroxide can be automatically sprayed.

The filter for a sterilizer of the present invention can be used not only for a sterilizer, but also for an air purifier, an air conditioner, an air conditioner, a dehumidifier, an automobile air conditioner and an air filter, an electric vacuum cleaner, and a filter for a clean room in a semiconductor research lab or a biotechnology lab.

In addition, the present invention

(a) a step of chelating an iron compound with a chelating agent;

(b) a step of chelating a copper salt with a chelating agent;

(c) a step of preparing a turbid solution by mixing the chelated iron compound and the chelated copper salt;

(d) a step of immersing the prepared turbidity in a carbonaceous material; and

(e) A method for manufacturing a filter for a sterilizer is provided, comprising the step of drying the carbonaceous material immersed in the above turbid solution at a temperature of 80°C to 100°C.

The above steps (a) and (b) have the effect of enabling rapid production of a large amount of hydroxyl radicals (or hydroperoxyl radicals) by forming a compound having a ring structure surrounding iron or copper as a central atom.

Each compound generated by chelating the iron compound with a chelating agent and chelating the copper salt with a chelating agent enables the reaction to be performed even in a neutral or alkaline state of about pH 8 to 10, rather than the conventional Fenton oxidation reaction, which required maintaining the pH between 3 and 4 for the reaction to occur. That is, in the conventional Fenton oxidation reaction, as in Equation (1), hydroxyl radicals are generated while oxidizing Fe(II) to Fe(III), and the oxidation reaction proceeds by these hydroxyl radicals. In this reaction, Fe(III) must be reduced back to Fe(II) by hydrogen peroxide for the Fenton oxidation reaction to continue. However, since the rate at which iron is oxidized is faster than the rate at which it is reduced, a phenomenon in which Fe(III) accumulates occurs, which greatly reduces the reaction efficiency, and ultimately, the reaction does not proceed any further. These catalysts with low efficiency are removed by increasing the pH using substances such as caustic soda to create insoluble iron hydroxide, but this process can generate a large amount of iron sludge that is a waste product. On the other hand, the present invention chelates the water-soluble iron compound with a chelating agent and chelates the copper salt with a chelating agent, and uses each compound generated in the Fenton oxidation reaction to generate radical species through hydrogen peroxide decomposition, so the reaction can be performed even in a neutral or slightly alkaline state (pH to 10), and environmental problems can be solved by eliminating the generation of iron sludge and enabling semi-permanent use of the iron catalyst.

The above step (c) enables a stable decomposition reaction while allowing for rapid and highly efficient generation of hydroxyl radicals (or hydroperoxyl radicals) by more rapidly decomposing hydrogen peroxide using the mixed turbidity. The above step (c) can be preferably performed at a pH of 8 to 10, and more preferably, the pH can be performed at 8.01.

In the above step (c), the molar ratio of the chelated iron compound and the chelated copper salt may be 1:0.05 to 2, and more preferably 1:0.1 to 1. If the molar ratio of the chelated copper salt is less than the above range, it may not sufficiently react with hydrogen peroxide, and thus the efficiency of generating hydroxyl radicals (or hydroperoxyl radicals) may be greatly reduced. If the molar ratio of the chelated copper salt exceeds the above range, unreacted sludge may be generated, which may rather cause environmental problems.

The above step (d) allows the turbidity to be stored without chemical transformation and facilitates transportation by sufficiently absorbing the turbidity into a carbonaceous material.

The manufacturing method of the present invention may further include, after step (d), a step of adding the carbonaceous material to a 0.5 mol HCl aqueous solution, stirring at room temperature, removing the precipitated carbonaceous material, washing it several times with distilled water, and drying it at 100°C. By pretreating the carbonaceous material with an acid and using it, it is possible to rapidly and efficiently generate hydroxyl radicals (or hydroperoxyl radicals) while enabling a stable decomposition reaction.

The above carbonaceous material may preferably have a size of 10-30 mesh, and more preferably have a size of 20-30 mesh.

The step (e) above can preferably be dried for 24 to 36 hours. This step prevents loss of the turbidity and chemical transformation of the turbidity by allowing the turbidity to be sufficiently immersed in a network of microscopic pores of a carbonaceous material (e.g., activated carbon).

The above iron compound may be water-soluble, and is preferably ferrous chloride (FeCl ₂ ), ferrous chloride (FeCl ₃ ), or ferrous sulfate (FeSO ₄ ). It may be at least one selected from the group consisting of ferric sulfate (Fe ₂ (SO ₄ ) ₃ ), ferrous acetate, ferric formate, ferrous gluconate, ferric glycophosphate, ferric nitrate, ferric oxalate, ferric citrate, ferric orthophosphate, ferrous iodide, ferrous lactate, and catocene, and more preferably ferric chloride (FeCl ₃ ).

The above copper salt may preferably be at least one selected from the group consisting of copper sulfate, copper chloride, copper nitrate, copper citrate, copper malate, copper oxalate, cuprous sulfide, and Cu-EDTA.

The chelating agent is preferably one selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), trans-1,2-diaminocyclohexane-N,N,N,N'-tetraacetic acid monohydrate (CyDTA), dihydroxyethylglycine (DHEG), ethylenediaminetetrakis(methylenephosphonic acid) (EDTPO), diethylenetriamine-N,N,N'N",N"-pentaacetic acid (DTPA), citric acid, diaminopropanoltetraacetic acid (EPTA-OH), ethylenediaminediacetic acid (EDDA), ethylenediamine-N,N'-bis(methylenephosphonic acid) 1/2 hydrate (EDDPO), 2-aminoethyl ethylene glycol tetraacetic acid (GEDTA), and hydroxyethylethylenediaminetriacetic acid (EDTA-OH), tartaric acid, citric acid, and oxalic acid. It may be, more preferably, ethylenediaminetetraacetic acid (EDTA).

The carbonaceous material may preferably be at least one selected from the group consisting of charcoal, activated charcoal, activated carbon, bituminous coal, impregnated activated carbon, bone char, acid washed activated carbon, coconut shell based activated carbon, wood-based activated carbon, regenerated activated carbon, anthracite coal, zeolite mixed coal, virgin activated carbon, water-washed catalytic carbon, and charred vegetation.

Hereinafter, the present invention will be described in detail with reference to the attached drawings and embodiments thereof. However, the following embodiments are provided as illustrative examples of the present invention. If a detailed description of a technology or configuration well known to those skilled in the art is judged to unnecessarily obscure the gist of the present invention, such detailed description may be omitted, and the present invention is not limited thereby. The present invention is capable of various modifications and applications within the scope of the following claims and equivalents interpreted therefrom.

Example 1. Preparation of a double metal catalyst 1

4.21 g (0.01 mol) of ethylenediaminetetraacetic acid monosodium iron salt (EDTA-NaFe Trihydrate) and 2.35 g (0.005 mol) of ethylenediaminetetraacetic acid copper disodium salt (EDTA-2NaCu Tetrahydrate) were diluted in 50 ml of distilled water at 60°C, 30 g of coconut shell activated carbon (20-30 mesh) was added, stirred for 30 minutes, and then taken out and dried under reduced pressure at 100°C for 24 hours to produce a catalyst containing chelated double metals.

Example 2. Preparation of a double metal catalyst 2

4.21 g (0.01 mol) of ethylenediaminetetraacetic acid monosodium iron salt (EDTA-NaFe Trihydrate) and 0.47 g (0.001 mol) of ethylenediaminetetraacetic acid copper disodium salt (EDTA-2NaCu Tetrahydrate) were diluted in 50 ml of distilled water at 60°C, 30 g of coconut shell activated carbon (20-30 mesh) was added, stirred for 30 minutes, taken out, and dried under reduced pressure at 100°C for 24 hours, thereby producing a catalyst containing chelated double metals.

Example 3. Preparation of a double metal catalyst 3

4.21 g (0.01 mol) of ethylenediaminetetraacetic acid monosodium iron salt (EDTA-NaFe Trihydrate) and 4.69 g (0.01 mol) of ethylenediaminetetraacetic acid copper disodium salt (EDTA-2NaCu Tetrahydrate) were diluted in 50 ml of distilled water at 60°C, 30 g of coconut shell activated carbon (20-30 mesh) was added, stirred for 30 minutes, taken out, and dried under reduced pressure at 80°C for 24 hours, thereby producing a catalyst containing chelated double metals.

Example 4. Preparation of a double metal catalyst 4

4.21 g (0.01 mol) of ethylenediaminetetraacetic acid monosodium iron salt (EDTA-NaFe Trihydrate) and 0.23 g (0.0005 mol) of ethylenediaminetetraacetic acid copper disodium salt (EDTA-2NaCu Tetrahydrate) were diluted in 50 ml of distilled water at 60°C, 30 g of coconut shell activated carbon (20-30 mesh) was added, stirred for 30 minutes, and then taken out and dried under reduced pressure at 100°C for 24 hours to produce a catalyst containing chelated double metals.

Example 5. Preparation of a double metal catalyst 5

4.21 g (0.01 mol) of ethylenediaminetetraacetic acid monosodium iron salt (EDTA-NaFe Trihydrate) and 9.38 g (0.02 mol) of ethylenediaminetetraacetic acid copper disodium salt (EDTA-2NaCu Tetrahydrate) were diluted in 50 ml of distilled water at 60°C, 30 g of coconut shell activated carbon (20-30 mesh) was added, stirred for 30 minutes, taken out, and dried under reduced pressure at 100°C for 24 hours, thereby producing a catalyst containing chelated double metals.

Comparative Example 1. Preparation of a single iron metal catalyst

4.21 g (0.01 mol) of ethylenediaminetetraacetic acid monosodium iron salt (EDTA-NaFe Trihydrate) was diluted in 50 ml of distilled water at 60°C, 30 g of coconut shell activated carbon (20-30 mesh) was added, stirred for 30 minutes, and then taken out and dried under reduced pressure at 100°C for 24 hours to produce a catalyst containing a chelated single metal.

Comparative Example 2. Preparation of a Copper Single Metal Catalyst

2.35 g (0.005 mol) of ethylenediaminetetraacetic acid copper disodium salt (EDTA-2NaCu Tetrahydrate) was diluted in 50 ml of distilled water at 60°C, 30 g of coconut shell activated carbon (20-30 mesh) was added, stirred for 30 minutes, and then taken out and dried under reduced pressure at 100°C for 24 hours to produce a catalyst containing a chelated single metal.

Comparative Example 3. Preparation of manganese dioxide impregnated catalyst

0.86 g (0.01 mol) of manganese dioxide was diluted in 50 ml of distilled water at 60°C, 30 g of coconut shell activated carbon (20-30 mesh) was added, stirred for 30 minutes, and then taken out and dried under reduced pressure at 100°C for 24 hours to produce a non-chelated manganese dioxide impregnated catalyst.

Comparative Example 4. Preparation of potassium permanganate-impregnated catalyst

1.58 g (0.01 mol) of potassium permanganate was diluted in 50 ml of distilled water at 60°C, 30 g of coconut shell activated carbon (20-30 mesh) was added, stirred for 30 minutes, and then taken out and dried under reduced pressure at 100°C for 24 hours to produce a non-chelated potassium permanganate-impregnated catalyst.

Experimental Example 1. Confirmation of Hydroxyl Radical Generation in Acids

A methylene blue solution treated with 6% hydrogen peroxide was prepared, and the color change of methylene blue was used as an indicator of hydroxyl radical production. 10 ml of methylene blue solution was prepared in each petri dish, and 0.5 g of each of the catalysts prepared in Examples 1 to 5 and Comparative Examples 1 to 4 was added to confirm each reaction (pH 4.8 before reaction). The time taken for the color of the methylene blue to change from blue to transparent was measured, and the results are shown in Table 1 below.

Reaction time Example 1 2 minutes 00 seconds Example 2 2 minutes and 10 seconds Example 3 3 minutes and 40 seconds Example 4 2 minutes and 10 seconds Example 5 More than 20 minutes Comparative Example 1 3 minutes and 10 seconds Comparative Example 2 18 minutes 00 seconds Comparative Example 3 9 minutes and 30 seconds Comparative Example 4 3 minutes or more

As shown in Table 1 above, it was confirmed that Example 1 had the shortest reaction time and thus generated the most hydroxyl radicals.

Experimental Example 2. Confirmation of Hydroxyl Radical Generation in Basic Conditions

A methylene blue solution treated with 6% hydrogen peroxide was prepared, and the color change of methylene blue was used as an indicator of hydroxyl radical production. 10 ml of methylene blue solution was prepared in each petri dish, and 0.5 g of each of the catalysts prepared in Examples 1 to 5 and Comparative Examples 1 to 4 was added to confirm each reaction (pH 8.95 before reaction). The time taken for the color of the methylene blue to change from blue to transparent was measured, and the results are shown in Table 2 below.

Reaction time Example 1 2 minutes 00 seconds Example 2 3 minutes 00 seconds Example 3 3 minutes and 15 seconds Example 4 2 minutes and 50 seconds Example 5 6 minutes 00 seconds Comparative Example 1 4 minutes and 30 seconds Comparative Example 2 2 minutes 00 seconds Comparative Example 3 7 minutes and 25 seconds Comparative Example 4 About 20% not decomposed

As shown in Table 2 above, it was confirmed that Example 1 had the shortest reaction time and thus produced the most hydroxyl radicals. Comparing the results in Table 2 with those in Table 1 above, there was no significant difference in reaction time, confirming that the influence of pH was not significant.

Experimental Example 3. Hydrogen Peroxide (H2O2) Decomposition Experiment

200 ml of a 6% aqueous hydrogen peroxide solution was placed in a 1 L spray bottle connected to an ultrasonic atomizer, and a carrier gas was constantly supplied at 130 ml/min using a mass flow controller (MFC) to maintain a hydrogen peroxide vapor concentration of 100 ppm. The hydrogen peroxide vapor concentration was analyzed by connecting a hydrogen peroxide sensor after filling 0.5 g of each of the catalysts according to Examples 1 to 5 and Comparative Examples 1 to 4 into a U-shaped reactor. The time for each hydrogen peroxide decomposition to end was measured, and the results are shown in Table 3 below.

Hydrogen peroxide decomposition time (pH 4.8) Hydrogen peroxide decomposition time (pH 8.95) Example 1 25 minutes 15 minutes Example 2 30 minutes 20 minutes Example 3 20 minutes 20 minutes Example 4 30 minutes 20 minutes Example 5 35 minutes 20 minutes Comparative Example 1 30 minutes 18 minutes Comparative Example 2 20 minutes 25 minutes Comparative Example 3 25 minutes 20 minutes Comparative Example 4 3 minutes 2 minutes and 20 seconds

As shown in Table 3 above, it was confirmed that, except for the potassium permanganate-impregnated catalyst, the hydrogen peroxide decomposition time of Example 1 was the shortest and hydroxyl radicals were most easily generated.

Experimental Example 4. Measurement of the reduction rate of suspended bacteria in the filter

A catalyst filter containing a catalyst according to the above Example 1 was tested according to KOUVA AS 02:2019. The airborne bacteria was S. epidermidis (ATCC 12228), and the airborne bacteria reduction rate of the air purification filter was measured under the conditions of a temperature of 23±2℃, a humidity of 50±5% RH, a test chamber of 60 m ³ , and a test time of 1 hour. The results are shown in Table 4 below, and to prove this, the air sterilization test report conducted by the Korea Testing Laboratory is shown in Figs. 5 and 6.

Floating bacteria reduction rate A sterilizer comprising a catalyst filter including a catalyst according to Example 1 95.6%

As shown in Table 4, Fig. 5, and Fig. 6, a high floating bacteria reduction rate of a sterilizer including a catalyst filter containing a catalyst according to Example 1 was confirmed.

Through the above experiment, it was confirmed that the dual metal catalyst filter containing both chelated iron and chelated copper has an excellent hydroxyl radical generation effect, is capable of generating hydroxyl radicals not only in acidic but also in alkaline conditions, and that the sterilizer containing the catalyst filter has a high efficiency in reducing floating bacteria and thus has an excellent air sterilization effect.

Claims (18)

An air purifying sterilizer comprising a catalytic filter that generates hydroxyl radicals:
The above catalyst filter,
It is prepared by immersing a turbidity containing an iron compound, a copper salt, and a chelating agent, and mixing the iron compound and the copper salt in a molar ratio of 1:0.1 to 1, in a carbonaceous material.
The above hydroxyl radical is,
An air purifying sterilizer characterized in that it is generated by a reaction with hydrogen peroxide sprayed by a sensor module, and causes a radical reaction even in a neutral to slightly alkaline (pH 8 to 10) state without a neutralizer, and iron sludge is not generated even after the radical reaction. delete In the first paragraph, the iron compound is ferrous chloride (FeCl ₂ ), ferrous chloride (FeCl ₃ ), or ferrous sulfate (FeSO ₄ ). An air purifying sterilizer, characterized in that it comprises at least one form selected from the group consisting of ferric sulfate (Fe ₂ (SO ₄ ) ₃ ), ferrous acetate, ferric formate, ferrous gluconate, ferric glycophosphate, ferric nitrate, ferric oxalate, ferric citrate, ferric orthophosphate, ferrous iodide, ferrous lactate, and catocene. An air purifying sterilizer, characterized in that in the third paragraph, the iron compound is ferric chloride (FeCl ₃ ). An air purifying sterilizer, characterized in that in the first paragraph, the copper salt is included in the form of at least one selected from the group consisting of copper sulfate, copper chloride, copper nitrate, copper citrate, copper malate, copper oxalate, cuprous sulfide, and Cu-EDTA. In the first claim, the chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), trans-1,2-diaminocyclohexane-N,N,N,N'-tetraacetic acid monohydrate (CyDTA), dihydroxyethylglycine (DHEG), ethylenediaminetetrakis(methylenephosphonic acid) (EDTPO), diethylenetriamine-N,N,N'N",N"-pentaacetic acid (DTPA), citric acid, diaminopropanoltetraacetic acid (EPTA-OH), ethylenediaminediacetic acid (EDDA), ethylenediamine-N,N'-bis(methylenephosphonic acid) 1/2 hydrate (EDDPO), 2-aminoethyl ethylene glycol tetraacetic acid (GEDTA), and hydroxyethylethylenediaminetriacetic acid (EDTA-OH), tartaric acid, citric acid, and oxalic acid. An air purifying sterilizer characterized by being included in one or more forms. An air purifying sterilizer, characterized in that in claim 6, the chelating agent is ethylenediaminetetraacetic acid (EDTA). delete In the first paragraph,
An air purifying sterilizer, characterized in that the above catalyst filter is arranged in a stack between a pre-filter and a HEPA filter. delete An air purifying sterilizer according to claim 1, characterized in that the carbonaceous material is at least one selected from the group consisting of charcoal, activated charcoal, activated carbon, bituminous coal, impregnated activated carbon, bone char, acid washed activated carbon, coconut shell based activated carbon, wood-based activated carbon, regenerated activated carbon, anthracite coal, zeolite mixed coal, virgin activated carbon, water-washed catalytic carbon, and charred vegetation. delete delete delete delete delete delete delete