KR102511994B1 - Manufacturing method of carbon filter coated with electrical catalyst and method of removing volatile organic compounds using the same - Google Patents

Abstract

The present invention relates to a method for manufacturing an electrocatalyst-coated carbon filter and a method for removing volatile organic compounds using the carbon filter produced thereby, and more particularly, to coating a carbon filter with an electrocatalyst exhibiting a catalytic phenomenon by electricity. Accordingly, it relates to an electrocatalyst coated carbon filter having excellent volatile organic compound removal function.

Description

Manufacturing method of carbon filter coated with electrical catalyst and method of removing volatile organic compounds using the same

The present invention relates to a method for manufacturing a carbon filter coated with an electrocatalyst having a volatile organic compound removal function, and a method for removing volatile organic compounds using the electrocatalyst coated carbon filter manufactured using the same.

As lifestyles including housing and work gradually change from outdoors to indoors with recent industrial development, the use of airtightness and insulation materials in buildings is increasing to maintain a pleasant indoor environment, reduce energy consumption, and improve thermal efficiency. However, as the indoor pollutant generation problem became serious, the problem of indoor air quality was raised, and related declarations and laws were announced. In Korea, related laws have also been enacted, and various studies are being conducted for indoor air quality management.

Among indoor pollutants, volatile organic compounds (VOCs) are commonly contained in various building materials including plywood and adhesives, and are also present in furniture, household items, insecticides, combustion appliances, cosmetics, perfumes, and the like. In addition, hydrocarbons that are widely used in daily life, such as liquid fuels with low boiling points, paraffins, olefins, and aromatic compounds, range from solvents widely used in industry to organic gases emitted from chemical and pharmaceutical factories or plastic drying processes. is almost applicable. Volatile organic compounds cause photochemical smog by forming photochemical oxidants such as ozone through photochemical reactions with nitrogen oxides (NOx) in the air, and substances such as benzene are carcinogenic and are very harmful to the human body. Organic compounds cause odors. The effects of volatile organic compounds on the human body include respiratory irritation, carcinogenicity, heart and liver, gastrointestinal nervous system and central nervous system abnormalities. It has been reported to cause acute disorders including cardiac arrhythmias, paralysis and death. Efforts are being made to reduce or remove volatile organic compounds as they have become a major social problem due to health damage, sick house syndrome, or chemical hypersensitivity caused by volatile organic compounds to the human body.

On the other hand, a photocatalyst is a material that causes various chemical reactions by absorbing light, and TiO ₂ , ZnO, ZnS, etc. are typical examples, and TiO ₂ is known to have the best efficiency when considering reaction conditions and activity. TiO ₂ photocatalyst is a semiconducting material that causes photooxidation, photoreduction, and hydrophilization when irradiated with light (380 nm or less). shows hydrophilicity due to the coordination effect of Superoxide anion (O ^2- ) is generated from oxygen and hydroxyl radical (*OH) is generated from water, and organic substances on the surface are decomposed by their decomposition. Due to these characteristics, photocatalysts are applied in various fields and are also used for decomposition and removal of volatile organic compounds in the air.

For example, Korean Patent Registration No. 10-0945311 discloses a composite photocatalytic filter equipped with a photocatalytic coating layer that is photoactivated by visible light to decompose pollutants in the air and an air purifying device using the same, and Korean Patent Publication No. 10 -2019-0063496 discloses a light source-integrated titanium dioxide photocatalyst filter.

However, despite the effectiveness of the photocatalytic reaction of titanium dioxide in contributing to air cleaning, there is a problem in that the performance as expected is not obtained due to problems in light irradiation efficiency, reaction area and throughput, and selectivity of the reaction, so improvement is needed. There is a demand for technology development capable of reducing and removing volatile organic compounds.

On the other hand, an electrocatalyst generates electrons by applying electricity to a metal oxide catalyst instead of light energy, and these electrons exist on the surface of metal oxide nanoparticles and then are transferred to oxygen to form superoxide anions (O ^2- ) from water. hydroxyl radical (*OH) is generated, and organic matter on the surface is decomposed by the decomposition of this active molecule. Due to these characteristics, electrocatalysts are applied in a wide range of fields, and are also used for decomposition and removal of volatile organic compounds in the air. Therefore, the photocatalyst has the disadvantage of using light, whereas the electrochemical catalyst has the advantage of not using light. On the other hand, a substrate that can directly apply electricity to the metal oxide catalyst is required. However, development of an electrocatalyst is non-existent.

The present invention has been made to solve the problems of the prior art as described above, and a method for manufacturing a carbon filter having volatile organic compound removal performance by coating titanium dioxide on a carbon fiber nonwoven fabric (a substrate to which electricity is applied) and a volatile organic compound using the same It is an object of the present invention to provide a method for removing a compound.

The present invention to achieve the above object, 1) preparing a first coating solution by dissolving a surfactant in a solvent; 2) coating the first coating solution on the carbon fiber nonwoven fabric; 3) preparing a second coating solution by mixing titanium dioxide and a silica binder; 4) coating the second coating solution on the carbon fiber nonwoven fabric coated with the first coating solution; and 5) drying the carbon fiber nonwoven fabric coated with the second coating solution.

The silica binder is tetraethyl orthosilicate, tetramethyl orthosilicate, methyltriethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane or ethyl tri It is ethoxysilane (Ethyltridethoxysilane),

The surfactant is triton x-100, sodium dodecyl sulfate, perfluorooctane sulfonate, sodium stearate, sodium lignosulfonate ( sodium lignosulfonate) and at least one selected from the group consisting of polystyrene sulfonate,

The solvent includes water or an organic solvent.

The titanium dioxide and the silica binder are mixed in a molar ratio of 1:0.2 to 5, and the surfactant is mixed in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the first coating solution.

The electrocatalyst coated carbon filter has a function of removing volatile organic compounds.

The coating method in steps 2) and 4) is a dip or spray method.

In another aspect, the present invention provides a step of applying a voltage to the electrocatalyst-coated carbon filter manufactured by the manufacturing method; and 2) removing volatile organic compounds in the air by the decomposition of the electrocatalyst coated on the electrocatalyst-coated carbon filter.

The electrocatalyst coated carbon filter according to the present invention is harmless to the human body as it uses titanium dioxide, which is chemically stable and harmless to the environment and the human body. It can be applied to various fields such as improvement, barn and food odor removal, and antibacterial removal in hospitals and schools.

In addition, it can be used for purifying devices in places or facilities where the concentration of volatile organic compounds is expected to be high among activity spaces such as bus stops and outdoor facilities.

In addition, since the present invention removes volatile organic compounds using an electrochemical reaction, it is economical because a separate light irradiation device is not required.

1 shows SEM measurement results of an electrocatalyst-coated carbon filter according to an embodiment.
2 shows CV measurement results of an electrocatalyst-coated carbon filter according to an embodiment.
Figure 3 shows the results of measuring the butane gas removal effect of the electrocatalyst-coated carbon filter according to an embodiment.
Figure 4 shows the results of measuring the volatile organic compound removal effect of the electrocatalyst coated carbon filter according to an embodiment.

Hereinafter, a method for manufacturing an electrocatalyst-coated carbon filter according to the present invention and a method for removing volatile organic compounds using the same will be described in detail.

The term "electrocatalyst" used in the present invention refers to a material in which a catalytic phenomenon occurs when electricity is applied.

A method for manufacturing an electrocatalyst-coated carbon filter according to the present invention includes the steps of 1) preparing a first coating solution by dissolving a surfactant in a solvent; 2) coating the first coating solution on the carbon fiber nonwoven fabric; 3) preparing a second coating solution by mixing titanium dioxide and a silica binder; 4) coating the second coating solution on the carbon fiber nonwoven fabric coated with the first coating solution; and 5) drying the carbon fiber nonwoven fabric coated with the second coating solution.

According to the present invention, by coating titanium dioxide on a carbon fiber nonwoven fabric having electrical conductivity, electricity can be applied to effectively remove volatile organic compounds by the high decomposition efficiency of the electrocatalyst and the adsorption mechanism of the carbon fiber nonwoven fabric.

Titanium dioxide is a material that excites the outermost electrons by sunlight or ultraviolet light included in fluorescent lamps or by applying electricity to excite the outermost electrons, and these excited electrons are transferred to oxygen or water and have strong redox ability. Due to its excellent electroactivity, it has advantages such as chemical and biological stability, durability, and economy. Looking at the basic decomposition principle of titanium dioxide, electrons are transferred to catalyst particles by light or electricity, and these electrons are transferred to water vapor on the surface of the catalyst to form hydroxyl radicals, which have strong oxidizing power. reacts with it to break it down. That is, the surface of titanium dioxide receives ultraviolet rays to generate cationic holes and negative electrons, where the holes undergo an oxidation reaction and the electrons undergo a reduction reaction to remove contaminants. This reaction is effective when titanium dioxide is activated. exerted However, there is a problem in that the activity of titanium dioxide may decrease as holes and electrons generated by ultraviolet rays recombine or as intermediate pollutants generated as the reaction proceeds adhere to the surface and the activity of the catalyst is lost. In addition, there is a limitation in requiring ultraviolet rays for activation. Accordingly, in the present invention, an electrocatalyst was prepared using a carbon fiber nonwoven fabric. According to the above principle, the electrocatalyst converts the electrons of the catalyst particles into electricity, which is transferred to water vapor on the surface of the catalyst particles to generate hydroxyl radicals, thereby performing decomposition.

The silica binder is an inorganic binder containing silica as a main component, and may be a commonly used silica-based binder, for example, tetraethyl orthosilicate, tetramethyl orthosilicate, methyltriethoxysilane (Methyltriethoxysilane), phenyltriethoxysilane, dimethyldimethoxysilane, or ethyltriethoxysilane, but is not limited thereto. Preferably it may be tetraethyl orthosilicate. The reason for using the silica binder is to prevent active species generated from the electrocatalyst from reacting with the substrate, and if an organic binder is used, active species generated from the electrocatalyst may react with the organic binder to generate recontamination.

As the surfactant, various nonionic surfactants, anionic surfactants, cationic surfactants, or amphoteric surfactants that are commonly used in the art can be used. For example, Triton x-100 (triton x-100) ), sodium dodecyl sulfate, perfluorooctane sulfonate, sodium stearate, sodium lignosulfonate and polystyrene sulfonate. It may be one or more selected from the group, but is not limited thereto. Preferably it may be triton x-100 (triton x-100).

The solvent may be any solvent commonly used in the art, and preferably may include water or an organic solvent, but is not limited thereto. The organic solvent may be an alcohol having a lower alkyl group, and for example, ethyl alcohol, methyl alcohol, butyl alcohol, secbutyl alcohol, propyl alcohol, isopropyl alcohol, or isopropanol may be used, but is not limited thereto.

The titanium dioxide and silica binder may be appropriately mixed in consideration of viscosity, etc., preferably at a molar ratio of 1:0.2 to 5, more preferably at a molar ratio of 1:0.5 to 2, but It is not limited.

The surfactant may be mixed in an appropriate ratio commonly used in the art, and for example, 0.5 to 5 parts by weight may be mixed with respect to 100 parts by weight of the first coating solution, and more preferably 1 to 3 parts by weight can However, it is not limited thereto.

The coating method in steps 2) and 4) may be a immersion or spray method, but is not limited thereto.

In another aspect, the present invention provides a step of applying a voltage to the electrocatalyst-coated carbon filter manufactured by the manufacturing method; and 2) removing volatile organic compounds in the air by the decomposition of the electrocatalyst coated on the electrocatalyst-coated carbon filter.

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 One]

Distilled water (pH 8.0, 50 mL), Triton x-100 (2 wt%), 2 mol of titanium dioxide (TiO ₂ ), and 1 mol of tetraethyl orthosilicate (hereinafter abbreviated as TEOS) were mixed to obtain a coating solution. After manufacturing, it was coated on a carbon fiber nonwoven fabric and then dried. Coating was carried out by immersion.

[ Example 2]

Carbon fiber nonwoven fabric is first coated with a mixture of distilled water (pH 8.0, 50 mL) and Triton x-100 (2 wt%), followed by a mixture of titanium dioxide (2 mol) and tetraethyl orthosilicate (1 mol). was coated and dried. Coating was carried out by immersion.

[ comparative example One]

Comparative Example 1 is a carbon fiber nonwoven fabric that has not been treated with anything.

[ Experimental example 1] Carbon filter surface analysis

The surface of the manufactured carbon filter was analyzed using a scanning electron microscope (FE-SEM (S-4800), Hitachi Co. Ltd, Japan) to confirm whether or not the coating was present. As shown in FIG. 1, Comparative Example 1 was not coated with anything, whereas in Examples 1 and 2 in which titanium dioxide was coated on the carbon fiber nonwoven fabric, it could be observed that the surface was coated with titanium dioxide. It can be seen that the coating of titanium dioxide was successfully performed on the surface of the carbon filter.

[ Experimental example 2] Analysis of electrochemical characteristics of carbon filter

Cyclic Voltammetry (VersaSTAT 3 Potentiostat Galvanostat, AMETEK PAR, USA) analysis was performed on the prepared carbon filter in PBS (pH 7.4, 30 mL) solution. At this time, a three-electrode system was used, and ITO glass was used as the working electrode, platinum wire was used as the counter electrode, and Ag/AgCl was used as the reference electrode. In FIG. 2, the width of the graph means the passage of electrons, and the wider the potential window, the easier the movement of electrons, which indicates conductivity. It can be seen that both of the carbon filters of Examples 1 and 2 have electrical conductivity, and it was confirmed that Example 2 has a wider potential window than Example 1, and that Example 2 has better conductivity.

[ Experimental example 3] Butane gas removal performance evaluation

Butane gas removal performance was evaluated for Example 1. First, butane gas was introduced into a 70 cm ³ acrylic box at 70Ψ for 30 minutes, and the gas was collected for 30 minutes with a gas collector (LFS-113, Sensidyne, LP). After removing the gas for 3 hours by applying 2V to the prepared carbon filter, the process of collecting the gas for 30 minutes was repeated three times and analyzed using GC (Gas Chromatography). As a result, as shown in FIG. 3, as a result of performing gas removal for 9 hours, it was confirmed that a butane gas removal rate of 42.81% was shown.

[ Experimental example 4] VOCs Removal performance evaluation

For Example 2, THF, ether, acetone, and toluene removal performance were evaluated. After vaporizing the above four solutions inside an acrylic box of 70 cm ³ scale, 2V was applied to the prepared carbon filter to remove gas, and the VOC sensor (HI-120A, Co., Ltd.) was measured using a VOC sensor (HI-120A, Humatech). As a result, referring to FIG. 4, the THF removal rate after 88 minutes was 27.71%, the ether removal rate after 64 minutes was 13.84%, the acetone removal rate after 38 minutes was 15.03%, and the toluene removal rate after 70 minutes was 24.93%. On average, it can be seen that the removal rate is 0.2 to 0.4 ppm per 10 to 15 minutes.

Compared to the results of Experimental Example 3, in the case of Example 1 in which the primary coating was performed on the carbon nonwoven fabric by mixing titanium dioxide, a binder, and a surfactant, a removal rate of 0.003 to 0.005 ppm per 10 to 15 minutes was shown, but carbon In the case of Example 2, in which a surfactant was first coated on the nonwoven fabric and then a solution of titanium dioxide and a binder was secondly coated, the removal rate was 0.2 to 0.4 ppm per 10 to 15 minutes, which was about 75 times higher than that of Example 1. performance can be seen. Through this, it can be seen that the case of coating the mixed solution of titanium dioxide and the binder after coating the surfactant first shows a better effect than the case of performing the first coating by mixing titanium dioxide, the binder, and the surfactant. Accordingly, it is considered that the electrocatalyst coated carbon filter prepared according to the present invention can be used as a filter for removing VOCs as the VOCs removal rate is excellent.

The above description is merely illustrative of the present invention, and those skilled in the art will be able to make various modifications without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in this specification are intended to explain, not limit, the present invention, and the spirit and scope of the present invention are not limited by these embodiments. The protection scope of the present invention should be construed according to the claims below, and all techniques within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (10)

1) preparing a first coating solution by dissolving a surfactant in a solvent;
2) coating the first coating solution on the carbon fiber nonwoven fabric;
3) preparing a second coating solution by mixing titanium dioxide and a silica binder;
4) coating the second coating solution on the carbon fiber nonwoven fabric coated with the first coating solution; and
5) drying the carbon fiber nonwoven fabric coated with the second coating solution; manufacturing method of an electrocatalyst coated carbon filter comprising
The method of claim 1, wherein the silica binder is tetraethyl orthosilicate, tetramethyl orthosilicate, methyltriethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane (Dimethyldimethoxysilane) or ethyl triethoxysilane (Ethyltridethoxysilane) Method for producing an electrocatalyst coated carbon filter
The method of claim 1, wherein the surfactant is triton x-100, sodium dodecyl sulfate, perfluorooctane sulfonate, sodium stearate, Method for manufacturing an electrocatalyst coated carbon filter, characterized in that at least one selected from the group consisting of sodium lignosulfonate and polystyrene sulfonate
The method of claim 1, wherein the solvent includes water or an organic solvent.
The method of claim 1, wherein the titanium dioxide and the silica binder are mixed in a molar ratio of 1:0.2 to 5.
The method of claim 1, wherein the surfactant is mixed in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the first coating solution.
The method of claim 1, wherein the electrocatalyst coated carbon filter has a function of removing volatile organic compounds.
The method of claim 1, wherein the coating method in steps 2) and 4) is immersion or spray method.
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