WO2023191463A1

WO2023191463A1 - Air-conditioning filter system for removing harmful substances

Info

Publication number: WO2023191463A1
Application number: PCT/KR2023/004133
Authority: WO
Inventors: 강신현; 임성환
Original assignee: 주식회사 퀀텀캣
Priority date: 2022-03-28
Filing date: 2023-03-28
Publication date: 2023-10-05

Abstract

The present invention relates to an air-conditioning filter system and, specifically, to an air-conditioning filter system, which continuously removes harmful gas present in a closed space through an air-conditioning filter part connected to the closed space, and then re-supplies purified air to the closed space so that a state in which harmful substances are not substantially present can be maintained.

Description

Air conditioning filter system for removing hazardous substances

The present invention relates to an air conditioning filter system, and more specifically, to continuously remove harmful gases present in an enclosed space through an air conditioning filter unit connected to the enclosed space, and then resupply the purified air to the enclosed space to prevent harmful substances in the enclosed space. It relates to an air conditioning filter system that can be maintained in a virtually non-existent state.

Spaces such as food production facilities and clean rooms in semiconductor factories are managed to maintain clean conditions by blocking external air and sealing to prevent external harmful substances or dust from entering. These special facilities maintain a strictly sealed environment, but there are various other closed spaces, and these closed spaces must be equipped with an air conditioning system that can discharge harmful substances generated inside to the outside and bring in clean air.

In particular, for workers working in confined spaces, long-term exposure to hazardous substances generated in confined spaces can lead to fatal accidents, so maintaining the cleanliness of air in confined spaces is very important. In order to maintain air purity, a technology has been known to install a filter box in an air conditioning system and passively adsorb harmful substances through a filter provided in the filter box.

Since the system that passively adsorbs harmful substances in the filter box follows the principle of isothermal adsorption, it is impossible to remove harmful substances beyond the capacity of the adsorbent, so there is a problem in that the adsorbent must be replaced periodically. Meanwhile, a technology that continuously removes harmful substances by housing a catalyst system that can decompose harmful substances in the filter box can be considered. However, in the case of photocatalysts, not only does it require continuous irradiation of light, but the catalyst activity is very low, so the concentration of harmful substances is low. It is difficult to quickly reduce and there is a problem in that energy must be continuously supplied to drive the light source. There is a known technology to continuously remove harmful substances by operating a catalyst system that operates under high temperature conditions. However, since it must be operated under high temperature conditions, not only does it require continuous supply of energy, but it also remains in the filter box as heating and cooling are repeated. There is a problem that the catalyst system is detached due to stress, reducing catalytic activity or flowing into a closed space.

Therefore, there is a need to develop a highly reliable air conditioning filter system that can continuously remove harmful gases present in a closed space without supplying energy, does not require replacement of filters, and maintains catalytic activity for a long period of time.

(Prior art literature)

(Patent Document 1) KR 10-2021-0129518 A (2021.10.28)

(Patent Document 2) KR 10-2022-0008415 A (2022.01.21)

The purpose of the present invention is to provide an air conditioning filter system that can continuously remove harmful gases present in an enclosed space without supplying energy.

Another object of the present invention is to provide an air conditioning filter system that operates at room temperature, is easy to handle, uses the filter semi-permanently, does not require replacement, and maintains catalytic activity for a long period of time, thereby providing high reliability.

In order to solve the problems described above, the present invention includes an air conditioning filter unit for removing harmful gases present in the indoor air of a closed space; an air inlet that communicates with one side of the air conditioning filter unit and allows air to flow in to receive air from the closed space; and an air outlet that communicates with the other side of the air conditioning filter unit and discharges air to supply air from which harmful gases have been removed from the air conditioning filter unit to the enclosed space. The air conditioning filter unit includes a catalytic reaction unit containing a porous composite structure catalyst and a housing accommodating the catalytic reaction unit therein, wherein the porous composite structure catalyst includes a porous substrate and a catalyst coating layer coated on the substrate. It provides an air conditioning filter system, wherein the catalyst coating layer includes a porous support including mesopores and a composite catalyst that is gold nanoparticles embedded in the pores of the porous support.

In one embodiment, the porous substrate may be a monolithic honeycomb ceramic structure, a metal foam structure, a bead, a pellet, or a HEPA filter.

In one embodiment, the air conditioning filter system may further include a pump for supplying air to the air conditioning filter unit between the air inlet and the sealed space.

In one embodiment, the porous support may be a metal oxide or metalloid oxide porous support.

In one embodiment, the diameter of the nanoparticles may be 1 to 20 nm.

In one embodiment, the porous composite structure catalyst may be used for an oxidation reaction of carbon monoxide, an aldehyde-based compound, or a hydrocarbon-based compound.

In one embodiment, the air conditioning filter system may be operated at 0°C to 60°C.

In one embodiment, the radial distribution function obtained by Fourier transforming the extended X-ray absorption fine structure (EXAFS) spectrum of the catalyst coating layer may satisfy Equation 1 below.

[Equation 1]

(DH2/DH1) < 0.25

In the above equation 1, DH1 is the height of the peak at the interatomic distance D1, DH2 is the peak height at the interatomic distance D2, and D1 and D2 satisfy the following equations 2 and 3, respectively.

[Equation 2]

0.8≤(D1/D3)≤0.95

[Equation 3]

0.6≤(D2/D3)≤0.7

In Equations 2 and 3 above, D3 refers to the interatomic distance of the Au-Au bond in the bulk phase existing at 2.8 to 3.0 Å.

In one embodiment, harmful gases present in the indoor air of a closed space may be removed at a removal rate of 90% or more under a space velocity condition of 12,000 hr ^-1 .

The air conditioning filter system according to the present invention can continuously remove harmful gases existing in an enclosed space without supplying energy, operates at room temperature conditions, is easy to handle, and uses the filter semi-permanently, eliminating the need for replacement and providing long-term protection. Catalytic activity is maintained and high reliability can be achieved.

Figure 1 shows a schematic diagram of an air conditioning filter system according to the present disclosure.

Unless otherwise defined, the technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art to which this invention pertains, and the gist of the present invention is summarized in the following description and accompanying drawings. Descriptions of known functions and configurations that may unnecessarily obscure are omitted.

Additionally, as used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly dictates otherwise.

In addition, units used without special mention in this specification are based on weight, and as an example, the unit of % or ratio means weight % or weight ratio, and weight % refers to the amount of any one component of the entire composition unless otherwise defined. It refers to the weight percent occupied in the composition.

In addition, the numerical range used in this specification includes the lower limit and upper limit and all values within the range, increments logically derived from the shape and width of the defined range, all double-defined values, and the upper limit of the numerical range defined in different forms. and all possible combinations of the lower bounds. Unless otherwise specified in the specification of the present invention, values outside the numerical range that may occur due to experimental error or rounding of values are also included in the defined numerical range.

The term 'comprise' in this specification is an open description with the same meaning as expressions such as 'comprising', 'contains', 'has' or 'characterized by', and includes elements that are not additionally listed, Does not exclude materials or processes.

The present inventor believes that in the case of existing air conditioning systems, adsorbents must be replaced periodically to remove harmful substances within a closed space, or must be operated under high temperature conditions while continuously supplying energy, resulting in stress accumulation due to heating and cooling, which causes catalyst damage. We noted that the activity of the system decreased over time and deepened our research to solve this problem. The present inventor discovered that the above problem could be solved by combining a porous composite structure catalyst that can operate at room temperature with an air conditioning filter unit, and completed the present invention.

An air conditioning filter system according to the present disclosure includes an air conditioning filter unit for removing harmful gases present in the indoor air of a closed space; an air inlet that communicates with one side of the air conditioning filter unit and allows air to flow in to receive air from the closed space; And an air outlet that communicates with the other side of the air conditioning filter unit and discharges air to supply air from which harmful gases have been removed from the air conditioning filter unit to the enclosed space, wherein the air conditioning filter unit includes a porous composite structure catalyst. A catalytic reaction unit and a housing for accommodating the catalytic reaction unit therein, wherein the porous composite structure catalyst includes a porous substrate and a catalyst coating layer coated on the substrate, and the catalyst coating layer is a porous support including mesopores. and a composite catalyst that is gold nanoparticles incorporated into the pores of the porous support.

The shape of the air conditioning filter unit is not limited to a specific shape, and may have a tubular shape, for example. The air conditioning filter unit is provided with a duct through which air flowing in from the closed space can pass, and the duct is provided with a catalytic reaction unit filled with a porous composite structure catalyst. The catalytic reaction unit is fixed inside the duct and airtightly fills a certain space inside the duct, allowing air flowing in the duct to pass through the catalytic reaction unit. The catalytic reaction unit includes a porous substrate composed of a plurality of fine cells to allow air to pass through, and a catalyst coating layer is formed on the porous substrate, so that the passing air reacts with the catalyst coating layer to remove harmful substances contained in the air. You can. Accordingly, by continuously circulating air containing harmful substances such as carbon monoxide and VOC present in the closed space and passing through the catalyst layer, harmful substances such as carbon monoxide and VOC within the closed space can be quickly removed at room temperature.

The composite catalyst may be included in an amount of 1 to 50 parts by weight, specifically 5 to 20 parts by weight, based on 100 parts by weight of the porous substrate to form a catalyst coating layer. The composite catalyst can be coated on the surface of the porous substrate to uniformly form a surface coating layer.

The composite catalyst may have an average particle diameter of 0.01 ㎛ to 10 ㎛, specifically 0.05 ㎛ to 5 ㎛, more specifically 0.1 ㎛ to 5 ㎛, but is not limited thereto.

According to one embodiment, the porous substrate may be a monolithic honeycomb ceramic structure, a metal foam structure, a bead, a pellet, or a HEPA filter.

The honeycomb ceramic structure may be a structure having a plurality of gas flow channels, and the cross-section of the flow channels may have various shapes such as squares, polygons such as hexagons, and circles, but may be selected without being limited to a specific shape. there is.

The honeycomb ceramic structure may be any one or two or more selected from the group consisting of metal oxides, metalloid oxides, metal carbides, and metalloid carbides. Specific examples include, but are not limited to, alumina, silica, and silicon carbide.

The metal foam structure may be a structure having open macropores, and metal materials may be used without limitation as long as they do not affect catalytic activity.

The porous substrate may have various shapes such as spherical, cylindrical, or polygonal, but may be selected without being limited to a specific shape.

According to one embodiment, when air is forcibly supplied from an enclosed space to supply air to the air conditioning filter unit, a separate air supply device may not be needed, and a rotating unit may optionally be further included inside the duct. Since the rotation unit is rotated by air flowing in from a closed space, no separate power is required to rotate the rotation unit, and the air flow is not interrupted. The rotating unit may be disposed on the inlet side of the air inlet or the outlet side of the air outlet.

According to one embodiment, a pump for supplying air to the air conditioning filter unit may be further included between the air inlet and the sealed space. When air is not forcibly supplied from the closed space, the air in the closed space must be forcibly circulated, so a pump can be placed in front of the air inlet of the air conditioning filter unit to supply air to the air conditioning filter unit and allow the air to circulate.

According to one embodiment, the space velocity of the air conditioning filter unit may be appropriately selected in consideration of the concentration of harmful gases, the volume of the enclosed space, etc., for example, 5,000 to 100,000 hr ^-1 , specifically 8,000 to 60,000 hr. ^-1 , more specifically, it may be 10,000 to 30,000 hr ^-1 . At this time, space velocity is the flow rate of air passing through the catalyst per 1L of catalyst. The air conditioning filter system according to one embodiment can effectively remove harmful gases contained in the air under high flow conditions.

According to one embodiment, the catalyst coating layer includes a metal oxide unit layer in which a plurality of composite catalyst particles are dispersed, and the metal oxide unit layer may be stacked on each other in the thickness direction to have a structure in which a plurality of unit layers are stacked. there is. The thickness of the unit layer may be 100 nm to 100 μm, but is not limited thereto. The metal oxide may be silica, alumina, or titania.

According to one embodiment, the catalyst coating layer is formed by coating an aqueous slurry containing a composite catalyst powder and at least one binder selected from the group consisting of an inorganic sol binder and a water-soluble polymer binder on a porous substrate to form a coating layer; and baking the porous substrate on which the coating layer is formed.

According to one embodiment, the water-soluble polymer binder may be any one or two or more selected from the group consisting of polyethylene glycol, polyvinyl alcohol, and poly(N-vinyl pyrrolidone). The water-soluble polymer binder may be included in an amount of 1 to 5% by weight in the aqueous slurry. The weight average molecular weight of the water-soluble polymer binder may be 10,000 to 1,000,000 g/mol, but is not limited thereto.

According to one embodiment, the inorganic sol binder may be silica sol, titania sol, or alumina sol, but is not limited thereto.

According to one embodiment, the porous support may be a metal oxide or metalloid oxide porous support. The metal or metalloid of the metal oxide or metalloid oxide may be from Groups 2 to 5, Group 7 to 9, and Group 11 to 14, and is specifically selected from Groups 2 to 4, Group 13, and Group 14. It may be a metal or metalloid, and more specifically, it may be Al, Ti, Zr, or Si.

The porous support includes mesopores and may optionally further include micropores. In the present disclosure, micropore means that the average diameter of internal pores is less than 2 ㎚, and mesopore (Mesopore) means that the average diameter of internal pores is 2 ㎚ to 50 ㎚.

The gold nanoparticles can be manufactured from methods known in the art or commercially available materials can be used. Specifically, gold nanoparticles can be produced by reducing a gold precursor present in a solution to gold according to a known method (Natan et al., Anal. Chem. 67, 735 (1995)). Examples of gold precursors include gold-containing halides, nitrates, acetates, acetylacetonates, or ammonium salts, but are not limited thereto. Specifically, the gold precursor may be HAuCl ₄ or HAuBr ₄ , but is not limited thereto.

The diameter of the gold nanoparticles may be 1 to 20 nm, specifically 1 to 15 nm, and more specifically 1 to 12 nm. A preferred diameter of gold nanoparticles may be 1 to 10 nm, more preferably 1 to 8 nm.

According to one embodiment, the average diameter of the nanoparticles may be larger than the average diameter of the mesopores of the porous support. Accordingly, it is possible to create a deformation of the crystal lattice of the gold nanoparticles incorporated into the mesopores of the porous support, and to improve catalytic activity in the room temperature range.

According to one embodiment, the nanoparticles may be incorporated into all of the mesopores of the porous support or may be incorporated into a portion of the mesopores of the porous support, and specifically, may be incorporated into a portion of the mesopores of the porous support. there is. More specifically, the nanoparticles may be irregularly incorporated into some of the mesopores of the porous support. At this time, the structure embedded in all of the mesopores of the porous support refers to a superlattice structure, and specifically refers to a highly ordered superlattice structure with face-centered cubic (FCC) symmetry. do. The shape in which nanoparticles are irregularly embedded in a portion of the mesopores has the advantage of allowing gas to diffuse more effectively compared to the superlattice structure.

According to one embodiment, the nanoparticles may be incorporated into some of the mesopores of the porous support, and the mesopores not incorporated into the nanoparticles may be connected to each other through open pores. In the composite catalyst, nanoparticles are incorporated into only a portion of the pores of the porous support, so that harmful gases can be diffused more effectively through pores that are not incorporated by nanoparticles connected to each other through open pores. Accordingly, even if the gas is supplied at a high flow rate at room temperature, substantially all of the reactant gas contained in the gas can be quickly converted into product gas.

According to one embodiment, the gold nanoparticles may be included in 0.1 to 10% by weight of the total weight of the catalyst coating layer, specifically 0.5 to 7% by weight, and more specifically 1 to 5% by weight. It may be.

According to one embodiment, the gold nanoparticles may be included in 0.005 to 3.5% by weight of the total weight of the porous composite structure catalyst, specifically 0.01 to 3% by weight, more specifically 0.05 to 2.5% by weight, or It may be included in 0.1 to 1.8 weight%.

According to one embodiment, the catalyst coating layer includes a porous support including mesopores and gold nanoparticles incorporated into the pores of the porous support, and the diameter obtained by Fourier transforming the EXAFS (Extended X-ray absorption fine structure) spectrum. The radial distribution function may satisfy Equation 1 below.

[Equation 1]

(DH2/DH1) < 0.3

In equation 1, DH1 is the height of the peak at the interatomic distance D1, DH2 is the height of the peak at the interatomic distance D2, and D1 and D2 are expressed in the following equations 2 and 3, respectively. Satisfies. Specifically, D1 and D2 are the interatomic distances of the maximum peak found in a range that satisfies the following Equations 2 and 3, respectively.

[Equation 2]

0.8≤(D1/D3)≤0.95

[Equation 3]

0.6≤(D2/D3)≤0.7

In Equations 2 and 3 above, D3 refers to the interatomic distance of the Au-Au bond in the bulk phase that exists at 2.8 to 3.0 Å, and may specifically exist at 2.88 to 2.98 Å, and more specifically, the standard of 2.90 Å. It may mean the distance between atoms. Specifically, D3 refers to the interatomic distance of the Au-Au bond in the bulk at 2.8 to 3.0 Å, obtained through peak deconvolution when the peak appears as a single peak with asymmetry or has a bimodal peak. can do. The asymmetry means that although the peak has the shape of a single peak (unimodal peak), the left and right sides have asymmetry based on the center of the peak as two peaks overlap.

Specifically, (D1/D3) in Equation 2 may be 0.85 to 0.92, and (D2/D3) in Equation 3 may be 0.63 to 0.66.

According to one specific example, in Equation 1, DH1 refers to the height of the peak at an interatomic distance of 2.57 ± 0.2 Å, and DH2 may refer to the height of the peak at an interatomic distance of 1.85 ± 0.2 Å. there is. Specifically, DH1 may refer to the peak height of an interatomic distance of 2.57 ± 0.1 Å, and DH2 may refer to the peak height of an interatomic distance of 1.85 ± 0.1 Å.

As the composite catalyst satisfies the height ratio of the peak at the interatomic distance D1 and the peak at the interatomic distance D2 of less than 0.3, the catalytic activity can be significantly improved.

EXAFS stands for extended X-ray absorption fine structure, and can analyze the diameter distribution or coordination number of gold nanoparticles. For example, when high-energy X-rays are irradiated to gold atoms, the gold atoms contained in the gold nanoparticles emit electrons. Accordingly, radial scattered waves are generated centered on the gold atom that absorbed the X-rays, and when the electrons emitted from the gold atom that absorbed the Electrons are emitted. At this time, radial scattered waves are generated centered on other adjacent atoms.

The scattered waves generated around the gold atom that absorbed the X-rays and the scattered waves generated around other adjacent atoms (gold or oxygen atoms) interfere. At this time, a standing wave is obtained depending on the distance between the gold atom that absorbed the X-rays and another atom (gold or oxygen atom) adjacent to the gold atom. When the standing wave is Fourier transformed, a radius distribution having a peak depending on the distance between a gold atom and another atom (gold or oxygen atom) adjacent to the gold atom is obtained. That is, not only the peak according to the distance between the gold (Au) atom and the gold (Au) atom, but also the distance between the gold (Au) atom with the Au-O bond and the oxygen atom when the gold (Au) atom has a bond with the oxygen atom. A diameter distribution with a peak according to can be obtained.

According to one specific example, (DH2/DH1) in Equation 1 may be 0.25 or less, more specifically 0.24 or less, and may be non-limitingly 0 or more. Preferably, (DH2/DH1) in Equation 1 may be 0.2 or less, and more preferably 0.15 or less. With the above numerical range, the catalytic activity of the porous composite structure catalyst is significantly improved, which is desirable in that substantially all of the reactant gas contained in the gas stream can be converted to product gas remarkably quickly.

According to one embodiment, the radial distribution function of the catalyst coating layer obtained by Fourier transforming an extended X-ray absorption fine structure (EXAFS) spectrum may satisfy Equation 4 below.

[Equation 4]

(DA2/DA1) < 0.25

In Equation 4, DA1 is the area of the peak at the interatomic distance D1, DA2 is the area of the peak at the interatomic distance D2, and D1 and D2 satisfy Equation 2 and Equation 3 above, respectively.

According to one specific example, in Equation 4, DA1 is the area of the peak with an interatomic distance of 2.57 ± 0.2 Å, and DA2 may mean the area of the peak with an interatomic distance of 1.85 ± 0.2 Å. there is. Specifically, DA1 may refer to the area of the peak with an interatomic distance of 2.57 ± 0.1 Å, and DA2 may refer to the area of the peak with an interatomic distance of 1.85 ± 0.1 Å.

As the composite catalyst satisfies the area ratio of the peak at the interatomic distance D1 and the peak at the interatomic distance D2 of less than 0.25, the catalytic activity can be significantly improved.

According to one embodiment, (DA2/DA1) in Equation 4 may be 0.2 or less, specifically 0.18 or less, more specifically 0.15 or less, and may be indefinitely 0 or more. Preferably, (DA2/DA1) in Equation 4 may be 0.1 or less, and more preferably 0.08 or less. With the above numerical range, the catalytic activity of the porous composite structure catalyst is significantly improved, which is desirable in that substantially all of the reactant gas contained in the gas stream can be converted to product gas remarkably quickly.

According to one embodiment, the diameter distribution function obtained by Fourier transforming the EXAFS (Extended Au) - Appears by bonds between gold (Au) atoms. Specifically, the 2.2 to 3.0 Å interatomic distance section may be a section where the distance between gold (Au) atoms is located, and refers to the distribution of the interatomic distance of Au-Au in the crystal lattice.

In the range of 2.2 to 3.0 Å between atoms, typical gold nanoparticles can exhibit a single peak, and having a single peak means that the distance between gold (Au)-gold (Au) atoms in the crystal lattice of the nanoparticle is It means that it is constant. However, having a bimodal peak may mean that different distances between gold (Au) and gold (Au) atoms exist in the crystal lattice. Although it has not been clearly identified, it may be related to the deformation of the crystal lattice due to compressive stress. It is inferred that two different distances between gold (Au) and gold (Au) atoms were created. As it has a bimodal peak in the interatomic distance range of 2.2 to 3.0 Å, it can exhibit very excellent catalytic activity even in low temperature ranges, and can convert substantially all of the reactant gas contained in the gas stream at high flow rate into product gas very quickly. It is desirable in that it can be done.

According to one embodiment, the porous composite structure catalyst may be used for the oxidation reaction of carbon monoxide, aldehyde-based compounds, or hydrocarbon-based compounds. Accordingly, the porous composite structure catalyst according to the present disclosure can be preferably used as a solid-phase oxidizing agent for carbon monoxide, aldehyde-based compounds, or hydrocarbon-based compounds. The aldehyde-based compound may be acetaldehyde or formaldehyde, but is not limited thereto. The hydrocarbon-based compound may be an aliphatic or aromatic compound or a volatile organic compound (VOC), and examples include, but are not limited to, methane, ethane, propane, butane, benzene, toluene, or xylene.

According to one embodiment, the air conditioning filter system may be operated at 0°C to 60°C, specifically at 10°C to 50°C, and more specifically at 15°C to 30°C, but is necessarily limited thereto. It doesn't work. By operating at a temperature in the above-mentioned range, it is possible to quickly remove harmful substances by solving problems arising from operating under high-temperature conditions while continuously supplying energy as described above.

According to one embodiment, the air conditioning filter system can remove harmful gases present in the indoor air of a closed space with a removal rate of 90% or more under space velocity conditions of 12,000 hr ^-1 or 24,000 hr ^-1 , preferably It can be removed with a removal rate of over 95%. Specifically, the harmful gas can be removed at a removal rate within the above-described temperature range and within the above-described range. At this time, the harmful gas may be carbon monoxide, and specifically, it may be carbon monoxide present in indoor air at a concentration of 0.1% or more.

Through the air conditioning filter system, carbon monoxide present at a concentration of 1% in the indoor air of a closed space can be removed at a removal rate of 70% or more under a space velocity condition of 12,000 hr ^-1 , preferably 80% or more, more preferably 80% or more. can be removed with a removal rate of over 90%. Specifically, the harmful gas can be removed at a removal rate within the above-described temperature range and within the above-described range.

For example, the enclosed space to which the air conditioning filter system is applied may have a volume of 0.1 to 100 m3 or 1 to 40 m3, but is not limited thereto.

Hereinafter, the present disclosure will be described in more detail using examples. However, the following examples are merely illustrative to aid understanding of the present application, and the content of the present application is not limited to the following examples.

(Preparation Example 1) Preparation of composite catalyst 1

[Step 1]: Preparation of polymer-functionalized gold nanoparticles

[Step 1-1]: Gold nanoparticles stabilized with oleylamine are synthesized according to the following procedure.

First, olein amine was selected as a stabilizer, and a solution consisting of 60 ml of tetralin, 60 ml of oleinamine, and 0.6 g of HAuCl·H ₂ O was prepared by stirring at room temperature for 10 minutes. 6 mmol of TBAB (tetrabutylammonium bromide), 6 ml of tetralin, and 6 ml of oleyl amine were mixed by ultrasonic pulverization and quickly added to the solution. Then, the solution was stirred at room temperature for another hour, ethanol was added, and then centrifuged to precipitate gold nanoparticles. The gold nanoparticle precipitate was redispersed with hexane, ethanol was added, and centrifuged. The produced gold nanoparticles had an average particle diameter of 4 nm, and the produced gold nanoparticles were dispersed as-formed in 100 ml toluene.

[Step 1-2]: The surface of the gold nanoparticle is functionalized with thiolated PEG using the following method.

In step 1-1, the gold nanoparticles dispersed in toluene were diluted by adding an additional 100 ml of tetrahydrofuran, and a thiolated polymer was selected for functionalization by binding the polymer to the surface of the gold nanoparticles, and 1 g of the terminal was added. Monofunctional polyethylene glycol (aSH-PEG, weight average molecular weight: 1 kDa) substituted with this thiol group was added. After stirring, hexane was added and centrifuged to precipitate gold nanoparticles (4-Au-PEG) functionalized with PEG. 4-Au-PEG obtained by precipitation was dried and then dispersed in water.

[Step 2]: Preparation of porous silica entrapped with PEG-functionalized gold nanoparticles

0.088g of 4-Au-PEG prepared in steps 1-2 above was mixed with 0.396g of Pluronic F127 as an activator and dispersed uniformly in 10ml of 1.6M HCl aqueous solution, and then 1.49g of tetraethylorthosilicate was added to the dispersion. (TEOS) was applied. Then, the dispersion of the mixture was stirred for 15 minutes and maintained without stirring at room temperature for 40 hours to prepare a red precipitate. The red precipitate thus formed corresponds to porous silica containing PEG-functionalized gold nanoparticles.

[Step 3]: Preparation of composite catalyst

The red precipitate prepared in the previous step was washed with water, dried, and then calcined in stages for 3 hours at 250°C, 2 hours at 400°C, and 2 hours at 500°C to remove PEG and Pluronic F127 polymers, thereby producing gold nanoparticles. A captured porous silica composite catalyst was prepared.

(Preparation Example 2) Preparation of composite catalyst 2

Composite catalyst 2 was prepared by performing steps 1 and 3 in the same manner, except that step 2 of Preparation Example 1 was performed as follows.

For the preparation of porous alumina containing PEG-functionalized gold nanoparticles in step 2, first prepare 0.15 g of PEG-functionalized gold nanoparticles (4-Au-PEG) and 0.675 g of Pluronic F127, and dissolve them in nitric acid (68% ) After uniformly dispersing in a mixed solution of 0.8 ml and 40 ml of ethanol, 0.81 g of aluminum ethoxide was added to the dispersion. The dispersion of the mixture was stirred for 3 hours, maintained at room temperature for 24 hours without stirring, and then dried at 60°C for 3 hours to prepare a red solid. Thereafter, step 3 of Preparation Example 1 was performed in the same manner to prepare porous alumina composite catalyst 2 containing gold nanoparticles.

(Preparation Example 3) Preparation of composite catalyst 3

Composite catalyst 3 was prepared by performing steps 1 and 3 in the same manner, except that step 2 of Preparation Example 1 was performed as follows.

For the preparation of porous titania containing PEG-functionalized gold nanoparticles in step 2, first prepare 0.10 g of PEG-functionalized gold nanoparticles (4-Au-PEG) and 0.44 g of Pluronic F127 and dissolve them in 37% hydrochloric acid. After uniformly dispersing in a mixed solution of 0.68 ml and 17.05 ml of ethanol, 2.28 g of titanium tetraisopropoxide was added to the dispersion. The dispersion of the mixture was stirred for 3 hours, maintained at room temperature for 24 hours without stirring, and then dried at 60°C for 3 hours to prepare a red solid. Thereafter, step 3 of Preparation Example 1 was performed in the same manner to prepare porous titania composite catalyst 3 in which gold nanoparticles were captured.

(Preparation Example 4) Preparation of porous composite structure catalyst 1

A dispersion was prepared by mixing the composite catalyst 1 prepared in Preparation Example 1 in an aqueous solution to 10% by weight and milling. The average particle diameter of the milled composite catalyst powder was 0.8㎛. Acetic acid was added to the dispersion to adjust the pH to 4, and an inorganic binder silica sol with an average particle diameter of 32 nm was mixed to make up 1% by weight of the dispersion. Then, poly(N-vinyl pyrrolidone), an organic binder, was mixed with the dispersion to make 2% by weight of the dispersion to prepare a slurry for coating.

10cm x 10cm x 10cm of the coating slurry The nickel foam was immersed for 1 minute and then removed. The excess slurry was removed by blowing air and dried sufficiently. The immersion and drying process was repeated 10 times, the coated nickel foam was charged into a high temperature furnace, and then fired at 450°C for 4 hours to finally prepare the porous composite structure Catalyst 1.

(Preparation Example 5) Preparation of porous composite structure catalyst 2

The same steps were performed except that gold nanoparticles with an average particle diameter of 10 nm were prepared by adjusting the molar ratio of oleinamine and HAuCl·H ₂ O in step 1-1 of Preparation Example 1, and Preparation Example 4 was the same. By carrying out this procedure, porous composite structure catalyst 2 was prepared.

(Preparation Example 6) Preparation of porous composite structure catalyst 3

The same steps 1 and 2 were performed as in Step 1-1 of Preparation Example 1, except that gold nanoparticles with an average particle diameter of 12 nm were prepared by adjusting the molar ratio of oleinamine and HAuCl·H ₂ O. In step 3, the red precipitate prepared in the previous step was washed with water, dried, and then calcined at 450°C to remove PEG and Pluronic F127 polymer to prepare a porous silica composite catalyst with trapped gold nanoparticles. Then, Preparation Example 4 was performed in the same manner to prepare porous composite structure catalyst 3.

(Preparation Example 7) Preparation of porous composite structure catalyst 4

A porous composite structure catalyst 4 was prepared in the same manner as Preparation Example 4, except that Composite Catalyst 2 of Preparation Example 2 was used instead of Composite Catalyst 1 of Preparation Example 1.

(Preparation Example 8) Preparation of porous composite structure catalyst 5

Porous composite structure catalyst 5 was prepared in the same manner as Preparation Example 4, except that composite catalyst 3 of Preparation Example 3 was used instead of composite catalyst 1 of Preparation Example 1.

(Example 1)

The porous composite structure catalyst 1 prepared in Preparation Example 4 is airtightly filled in the tubular air conditioning filter unit, and the air inlet and air outlet are each connected to a sealed space as shown in the schematic diagram of FIG. 1, and then a pump is installed in front of the air conditioning filter unit. was installed to force air circulation.

(Example 2)

The same procedure as Example 1 was carried out, except that the porous composite structure catalyst 2 of Preparation Example 5 was used instead of the porous composite structure catalyst 1 of Preparation Example 4.

(Example 3)

The same procedure as Example 1 was carried out, except that the porous composite structure catalyst 3 of Preparation Example 6 was used instead of the porous composite structure catalyst 1 of Preparation Example 4.

(Experimental Example 1) EXAFS (Extended X-ray absorption fine structure) analysis

EXAFS (Extended X-ray absorption fine structure) measurements were performed using the 4C and 10C beamlines of the Pohang Accelerator (PLS-II). The EXAFS spectrum was Fourier transformed to obtain a radial distribution function.

As a result of analyzing the diameter distribution function of the catalyst coating layer included in the porous composite structure catalyst according to Preparation Examples 4 to 8, a peak due to Au-O bond was observed in the range of 1.4 to 1.7 Å in all cases. From this, the proximity between the surface of the gold nanoparticles and the porous support that captures them provides conditions for forming stable Au-O bonds at the interface between the gold nanoparticles and the porous support, resulting in Au-O-Si, Au-O-Al Alternatively, it can be confirmed that Au-O-Ti is formed.

In addition, in all of Preparation Examples 4 to 8, a peak due to bulk Au-Au bond was observed in the range of 2.8 to 3.0 Å, and when the interatomic distance of this peak is called D3, the peak of the diameter distribution function based on D3 defined. Specifically, D1 and D2 are the interatomic distances of the maximum peak found in a range that satisfies the following equations 2 and 3, respectively, and the positions of D1, D2, and D3 are shown in Table 1. In addition, the ratio of the height (DH1) and area (DA1) of the peak at the interatomic distance D1 and the height (DH2) and area (DA2) of the peak at the interatomic distance D2 were calculated and shown in Table 1.

[Equation 2]

0.8≤(D1/D3)≤0.95

[Equation 3]

0.6≤(D2/D3)≤0.7

	제조예 4Production example 4	제조예 5Production example 5	제조예 6Production example 6	제조예 7Production example 7	제조예 8Production example 8
DH2/DH1DH2/DH1	00	0.2270.227	0.3350.335	00	00
DA2/DA1DA2/DA1	00	0.1290.129	0.2270.227	00	00
D1D1	2.5522Å2.5522Å	2.5893Å2.5893Å	2.567Å2.567Å	2.5607Å2.5607Å	2.5939Å2.5939Å
D2D2	--	1.8471Å1.8471Å	1.848Å1.848Å	--	--
D3D3	2.906Å2.906Å	2.8967Å2.8967Å	2.8177Å2.8177Å	2.9601Å2.9601Å	2.9526Å2.9526Å
D1/D3D1/D3	0.87830.8783	0.8940.894	0.9110.911	0.86510.8651	0.87850.8785
D2/D3D2/D3	--	0.6380.638	0.6560.656	--	--

(Experimental Example 2) Carbon monoxide removal rate experiment in a closed space

An experiment on the carbon monoxide removal rate of the air conditioning filter system according to Examples 1 to 3 was performed. Carbon monoxide was introduced at a certain concentration into a 1 ㎥ enclosed space, and the flow rate of air supplied to the air conditioning filter unit was adjusted at room temperature (20°C), and the average concentration of carbon monoxide inside the enclosed space was measured 30 minutes after the introduction of carbon monoxide. . Specifically, carbon monoxide concentration was measured using an infrared continuous gas analyzer (Siemens, ULTRAMAT 23). Table 2 shows the carbon monoxide removal rate according to the concentration and space velocity of the introduced carbon monoxide (=supplied flow rate per 1L of catalyst).

	CO 0.1%, 12,000 hr^-1 CO 0.1%, 12,000 hr ^-1	CO 0.1%, 24,000 hr^-1 CO 0.1%, 24,000 hr ^-1	CO 1%, 12,000 hr^-1 CO 1%, 12,000 hr ^-1
실시예 1Example 1	100%100%	97%97%	90%90%
실시예 2Example 2	100%100%	92%92%	68%68%
실시예 3Example 3	100%100%	80%80%	55%55%

Referring to Table 2, Examples 1 to 3 all showed a 100% removal rate under the conditions of a carbon monoxide concentration of 0.1% and a space velocity of 12,000 hr ^-1 , showing that carbon monoxide was removed even though air was simply circulated through a pump at room temperature. has been completely removed.

Meanwhile, at a higher space velocity of 24,000 hr ^-1 , Examples 1 and 2 showed removal rates of 97% and 92%, respectively, effectively removing carbon monoxide compared to Example 3. In particular, Example 1 showed a removal rate of 90% under conditions of higher concentration of carbon monoxide.

It can be seen that the air conditioning filter system according to one embodiment can effectively remove harmful gases contained in the air even when air containing harmful substances is supplied at a high flow rate at room temperature.

As described above, the present invention has been described with specific details, limited embodiments, and drawings, but these are provided only to facilitate a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention Anyone skilled in the art can make various modifications and variations from this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and the scope of the patent claims described below as well as all modifications that are equivalent or equivalent to the scope of this patent claim shall fall within the scope of the spirit of the present invention. .

(Explanation of symbols)

11: Catalytic reaction section

13: Housing

20: air inlet

30: air outlet

50: confined space

60: pump

Claims

An air conditioning filter unit for removing harmful gases present in the indoor air of a closed space;

an air inlet that communicates with one side of the air conditioning filter unit and allows air to flow in to receive air from the closed space; and

an air outlet that communicates with the other side of the air conditioning filter unit and discharges air to supply air from which harmful gases have been removed from the air conditioning filter unit to the enclosed space;

Including,

The air conditioning filter unit includes a catalytic reaction unit containing a porous composite structure catalyst and a housing accommodating the catalytic reaction unit therein,

The porous composite structure catalyst includes a porous substrate and a catalyst coating layer coated on the substrate, and the catalyst coating layer includes a porous support including mesopores and a composite catalyst that is gold nanoparticles embedded in the pores of the porous support. An air conditioning filter system, characterized in that.
According to paragraph 1,

An air conditioning filter system, wherein the porous substrate is a monolithic honeycomb ceramic structure, a metal foam structure, a bead, a pellet, or a HEPA filter.
According to paragraph 1,

An air conditioning filter system further comprising a pump for supplying air to the air conditioning filter unit between the air inlet and the sealed space.
According to paragraph 1,

The air conditioning filter system wherein the porous support is a metal oxide or metalloid oxide porous support.
According to paragraph 1,

An air conditioning filter system wherein the nanoparticles have a diameter of 1 to 20 nm.
According to paragraph 1,

The porous composite structure catalyst is an air conditioning filter system for the oxidation reaction of carbon monoxide, aldehyde-based compounds, or hydrocarbon-based compounds.
According to paragraph 1,

The air conditioning filter system is operated at 0 ℃ to 60 ℃.
According to paragraph 1,

An air conditioning filter system in which the radial distribution function obtained by Fourier transforming the extended X-ray absorption fine structure (EXAFS) spectrum of the catalyst coating layer satisfies the following equation 1:

[Equation 1]

(DH2/DH1) < 0.25

In the above equation 1, DH1 is the height of the peak at the interatomic distance D1, DH2 is the peak height at the interatomic distance D2, and D1 and D2 satisfy the following equations 2 and 3, respectively:

[Equation 2]

0.8≤(D1/D3)≤0.95

[Equation 3]

0.6≤(D2/D3)≤0.7

In Equations 2 and 3 above, D3 refers to the interatomic distance of the Au-Au bond in the bulk phase existing at 2.8 to 3.0 Å.
According to clause 8,

An air conditioning filter system that removes harmful gases present in the indoor air of a closed space with a removal rate of more than 90% under a space velocity condition of 12,000 hr -1 .