KR102137766B1 - Manufacturing method of a metal textile typed photocatalyst filter, the metal textile typed photocatalyst filter manufatured therefrom, a photocatalyst filter module and a cleaner the same - Google Patents

Abstract

The present invention provides a method for manufacturing a metal textile typed photocatalyst filter, including: (S1) a step of preparing a metal textile including stainless steel wire having 15 wt% or more of chromium content; (S2) a step of primarily performing heat treatment for the metal textile at a temperature of 600-800°C; (S3) a step of forming a titanium dioxide coating layer on the surface of the metal textile subjected to high temperature heat treatment through chemical vapor deposition; and (S4) a step of secondarily performing heat treatment for a metal textile coated with the titanium dioxide coating layer at a temperature of 400-500°C. According to the manufacturing method of the present invention, there may be manufactured a metal textile type photocatalytic filter with improved pollutant resolution, through a simpler manner, and at an economical cost.

Description

Manufacturing method of metal fabric type photocatalyst filter, metal fabric type photocatalyst filter manufactured therefrom, photocatalyst filter module and purifier having same {Manufacturing method of a metal textile typed photocatalyst filter, the metal textile typed photocatalyst filter manufatured therefrom, a photocatalyst filter module and a cleaner the same}

The present invention is a method of manufacturing a metal fabric type photocatalyst filter having a function of decomposing and removing contaminants using the photocatalytic activity of titanium dioxide, a metal fabric type photocatalyst filter prepared therefrom, a photocatalyst filter module and a purifier having the same It is about.

It is well known that titanium dioxide is activated by light, particularly ultraviolet light, to decompose and remove various organic and inorganic pollutants. The decomposition reaction of these pollutants is initiated by absorbing energy above the band gap of titanium dioxide (3.2eV based on anatase crystals) from light.

However, in order to remove contaminants from air or liquid flowing at a high speed, the activity of the titanium dioxide photocatalyst is low, and thus there is a limit to practical use.

The main reason for the low titanium dioxide photocatalytic activity is that, first, titanium dioxide does not have sufficient UV absorption, the main light source for photocatalytic reactions, and secondly, recombination occurs easily because electrons and holes generated by the photocatalytic reaction are unstable. to be.

To solve these problems, many studies are being conducted. Method of changing bandgap energy to prevent recombination of photoelectric charges and increase electron-hole transfer rate by injecting different types of metals or nonmetals into the crystal structure of a photocatalyst that is a metal oxide to change the density and binding energy inside The back is typical. For example, a method of hybridizing a noble metal with a photocatalytic material (Korea Patent No. 10-1060200), a method of coating a metal with a photocatalyst material through sputtering (Korea Patent No. 10-1465299), doping metal ions or nitrogen ions into the photocatalytic material Method (Korea Patent Registration No. 10-0726336), a method of hybridizing a complex between different semiconductors having a relatively small band gap (Korea Patent Registration No. 10-1446327), and a method of making a hybrid photocatalytic structure using a carbon substrate (Korea Patent Registration No. 10 -1802590 and Korean Patent No. 10-1576635).

However, the above-described methods have problems in that they need to be manufactured through a complicated multi-step process by applying expensive equipment, or they do not satisfy the economical efficiency in commercial mass production, not in the laboratory level.

The object of the present invention was devised in consideration of the technical background as described above, a method for manufacturing a metal fabric type photocatalyst filter with improved pollutant resolution of titanium dioxide at a relatively simple and economical cost, and a metal fabric type produced therefrom It is to provide a photocatalyst filter, a photocatalyst filter module and a purifier having the same.

To achieve the above object, a method of manufacturing a metal fabric type photocatalyst filter according to the present invention,

(S1) preparing a metal fabric made of stainless steel wire having a chromium content of 15% by weight or more;

(S2) the primary heat treatment of the metal fabric at a temperature of 600 to 800 ℃;

(S3) forming a titanium dioxide coating layer on the surface of the high-temperature heat-treated metal fabric using chemical vapor deposition; And

(S4) a second heat treatment of the metal fabric formed with the titanium dioxide coating layer at a temperature of 400 to 500°C.

In the method of manufacturing a metal fabric type photocatalyst filter according to the present invention, the average diameter of the stainless steel wire is 0.035 to 1.0 mm, and the porosity of the metal fabric may be 30% or more.

In the method of manufacturing a metal fabric type photocatalyst filter according to the present invention, the surface of the metal fabric after the first heat treatment may have chromium oxide of 50% by weight or more.

In the method of manufacturing a metal fabric type photocatalyst filter according to the present invention, the chemical vapor deposition is preferably performed at 400 to 440°C.

In addition, the present invention is a filter unit including a metal fabric type photocatalyst filter manufactured by the above-described methods; And

It provides a photocatalyst filter module having a light source unit equipped with a light emitting diode lamp for irradiating ultraviolet rays to the metal fabric type photocatalyst filter.

In the photocatalyst filter module of the present invention, it is possible to further include a honeycomb structure passage unit that induces contaminants to pass through the filter unit uniformly.

The photocatalyst filter module is provided in a purifier such as an air purifier and can be usefully used for purifying organic or inorganic pollutants.

According to the manufacturing method of the present invention, the titanium dioxide photocatalyst can be formed as a coating layer on an inexpensive stainless steel wire to weave in the form of a fabric to ensure good weavability, and the durability of the filter is also very good.

In addition, a relatively simple method of performing a primary heat treatment-forming a titanium dioxide coating layer by chemical vapor deposition-secondary heat treatment of a fabric made of stainless steel wire containing a certain amount or more of chromium efficiently doping chromium on the titanium dioxide coating layer By doing so, the photocatalytic activity of the titanium dioxide coating layer is improved.

Since the metal fabric type photocatalyst filter manufactured in this way has good pollutant resolution, it is manufactured as a photocatalyst filter module together with a light source unit equipped with a light emitting diode lamp for irradiating ultraviolet rays, and is useful as a purifier such as an air purifier.

1 is a schematic configuration diagram of a photocatalyst filter module according to an aspect of the present invention,
Figure 2 is a prototype picture of a photocatalyst filter module according to an aspect of the present invention,
3 is an X-ray diffraction analysis graph of the surface before and after performing the first heat treatment of the metal fabric according to Example 1 of the present invention,
Figure 4 (a) is a SEM image of the surface before and after the first heat treatment of the metal fabric according to the first embodiment of the present invention, (b) is the first heat treatment of the metal fabric according to the first embodiment of the present invention Table before and after surface component analysis using a scanning electron microscope-energy dispersion analysis method (SEM-EDX method),
Figure 5 (a) is an X-ray diffraction analysis graph of the titanium dioxide coating layer according to the process temperature changes when forming a titanium dioxide coating layer using a chemical vapor deposition according to an embodiment of the present invention, (b) is for these SEM photograph, (c) is a graph showing the flatness (RMS) of these surfaces analyzed by atomic force microscopy (AFM),
Figure 6 (a) is the absorbance of the UV-visible region of the metal fabric type photocatalyst filter obtained according to Example 1 and Comparative Example (b) is a representative wavelength of ultraviolet A (365nm) of Example 1 and Comparative Example It is a graph that evaluates the photocatalytic activity by measuring the concentration change in which the metal fabric type photocatalyst filter decomposes the organic material, nitrobenzene.

Hereinafter, the present invention will be described in detail. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to ordinary or lexical meanings, and the inventor appropriately explains the concept of terms in order to explain his or her invention in the best way. Based on the principle that it can be defined, it should be interpreted as meanings and concepts consistent with the technical spirit of the present invention. Therefore, the embodiments shown in the embodiments and the drawings described in this specification are only the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention, and thus can replace them at the time of application. It should be understood that there may be equivalents and variations.

According to the method of manufacturing a metal fabric type photocatalyst filter according to the present invention, first, a metal fabric made of stainless steel wire having a chromium content of 15% by weight or more is prepared (step S1).

Commercially available stainless steels are provided with the contents of the components, and stainless steels having a chromium content of 15% by weight or more include, but are not limited to, austenitic stainless steels. When the chromium content in the stainless steel wire is 15% by weight or more, a chromium oxide layer is sufficiently formed on the surface of the stainless steel wire by a primary heat treatment, which will be described later, so that chromium doping can be smoothly performed with the titanium dioxide coating layer by a subsequent step.

Methods of weaving metal fabrics using stainless steel wire are well known in the art. For example, a metal fabric may be woven in a structure such as plain weave or twill weave using stainless steel wire. The average diameter of this ‹š, stainless steel wire is 0.035 to 1.0 mm, and the porosity of the metal fabric is 30% or more, which is advantageous when considering the weavability, durability, and differential pressure of the filter system. Weaving density is preferably 13*13 picks/mm ² or less, but is not limited thereto.

Subsequently, the metal fabric is first heat-treated at a temperature of 600 to 800°C (step S2).

The metal fabric may be subjected to a cleaning process to remove impurities on the surface before the first heat treatment, if necessary. Washing may be performed by immersing in weakly acidic water or methanol for a sufficient period of time to remove impurities, and then washing with ion-removed water.

The metal fabric may be subjected to primary heat treatment by, for example, 1 to 2 hours heat treatment in a heat treatment furnace at 600°C to 800°C capable of supplying air or oxygen. Through the primary heat treatment process, the oxide layer on the surface of the metal fabric that is already naturally formed is further strengthened and thickened. Chromium oxide (Cr ² O ^3, etc.), iron oxide (Fe ² O ^3, etc.), nickel oxide (NiO, etc.) are additionally formed on the surface of the metal fabric according to the first heat treatment to form a metal oxide layer.

Depending on the heat treatment temperature and time, the content ratio of a specific component may be increased or decreased.

When the primary heat treatment temperature is less than 600° C., the relative content ratio of iron oxide, which is weak in durability, increases, and when the heat treatment temperature increases, the content ratio of chromium oxide, which has excellent durability, increases. However, the chromium oxide content ratio does not increase significantly when the temperature exceeds 800°C. In addition, as the primary heat treatment temperature approaches 800°C, the metal oxide layer on the surface of the metal fabric is strengthened so that sufficient chromium oxide or the like is present on the surface and has a metal oxide layer having excellent durability that can be used for a long time as a filter substrate. The heat treatment process is preferably maintained for 1 hour or more, and then quenched by a method of circulating air at room temperature. It is preferable to control the heat treatment temperature and time so that the surface of the metal fabric after the first heat treatment is 50 wt% or more of chromium oxide.

Then, a titanium dioxide coating layer is formed on the surface of the metal fabric primarily heat-treated at high temperature using chemical vapor deposition (step S3).

By forming a coating layer of a titanium dioxide photocatalyst on the surface of a metal fabric using chemical vapor deposition (CVD), it is possible to maximize the surface area and grow the titanium dioxide particles in the coating layer into a nanostructure.

In chemical vapor deposition, titanium tetra-isopropoxide (TTIP) or tetrabutyltitanate (TBOT) may be used as the titanium precursor to proceed in an inert carrier gas.

The temperature at the time of chemical vapor deposition is preferably performed at 400 to 440°C. When chemical vapor deposition is performed in a temperature range that is not relatively high, the flatness of the titanium dioxide coating layer is good, but it is advantageous to slowly grow the formed titanium dioxide crystal structure to the anatase type and have a specific surface area of a certain level or more.

Subsequently, the metal fabric having the titanium dioxide coating layer formed thereon is subjected to a second heat treatment at a temperature of 400 to 500°C (step S4).

In addition to the function of improving the weak chemical bond between the titanium dioxide coating layer formed by chemical vapor deposition and the metal fabric by performing secondary heat treatment and improving the flatness through an annealing effect, the surface of the metal oxide layer formed on the surface of the metal fabric by thermal diffusion of chromium ions stably (Thermal diffusion) metal ions, such as in the crystal structure of the titanium dioxide coating (Cr + ^3), thereby increasing the bonding sikimeuroseo photocatalytic activity. The chromium ion present in the metal oxide layer of the metal fabric has a band gap lower than the band gap energy (3.2 eV) of the anatase structure of the titanium dioxide coating layer, thereby forming an electron capture site in the crystal of titanium dioxide in the second heat treatment process. It acts as a barrier to the binding of electrons and holes, increasing photocatalytic activity. The secondary heat treatment may be performed by heat-treating the metal fabric formed with the titanium dioxide coating layer at 400 to 500° C. in a heat treatment furnace in the atmosphere for at least 1 hour, and naturally cooling the heat treatment furnace. If the secondary heat treatment temperature is less than 400°C, it is difficult to expect sufficient thermal diffusion of chromium ions, and if it exceeds 500°C, the possibility of the titanium dioxide crystal structure being converted to a rutile type increases, which may make it difficult to improve the photocatalytic activity.

The metal fabric-type photocatalyst filter manufactured by the above-described method has good contaminant resolution and is manufactured by a photocatalyst filter module, and thus can be usefully used as a purifier such as an air purifier.

Therefore, the present invention is made of a photocatalyst filter module together with a light source unit equipped with a light emitting diode lamp for irradiating ultraviolet rays, and is useful as a purifier such as an air purifier.

A filter unit including a metal fabric type photocatalyst filter manufactured by the above-described method; And

It provides a photocatalyst filter module having a light source unit equipped with a light emitting diode lamp for irradiating ultraviolet rays to the metal fabric type photocatalyst filter.

FIG. 1 is a schematic configuration diagram of a photocatalyst filter module according to an aspect of the present invention, and FIG. 2 is a prototype photograph implementing this. Hereinafter, a case for purifying a gas such as air will be described as an example.

As shown in FIG. 1, the photocatalyst filter module includes a metal fabric type photocatalyst filter manufactured by the method described above, and a light source unit equipped with a light emitting diode lamp for irradiating ultraviolet rays to the metal fabric type photocatalyst filter. As a light source unit, it is preferable to use a light source unit equipped with a plurality of LED lamps in order to secure a sufficient amount of ultraviolet light. As shown in Fig. 1, the LED lamp is preferably in the form of a bar in which a number of UV LED chips are mounted, and a number of these LED lamps are prepared and placed parallel to each other, but taking into account the spacing of the LED chips and the angle of light irradiation. You can adjust the interval. The LED lamp is preferably fixed to a square frame to form one unit, but if necessary, it can also be fixed directly to the internal body of the product such as an air purifier or an air conditioner.

As illustrated in FIG. 1, the photocatalyst filter module of the present invention may further include a honeycomb structure passage unit that induces contaminants to pass through the filter unit uniformly. By providing the honeycomb structured passage unit, it is possible to exclude the influence of wind volume or wind speed. The honeycomb structured passage unit is preferably made of aluminum as a material that is durable against long-term oxidation-reduction reactions and can reflect LED lamp light. The passage unit of the honeycomb structure is located toward the direction in which the air flows, and the hole size of a single honeycomb can be adjusted according to the application, and the thickness is adjusted according to the flow form of the air passing through, but generally 10 to 30 mm is preferable.

The metal fabric type photocatalyst filter can be selectively positioned on the front or rear of the honeycomb structured passage unit and positioned to facilitate even contact with the air including light sources and contaminants. At this time, the metal fabric type photocatalyst filter may be modularized by fixing the honeycomb structure passage unit frame together as shown in FIG. 2. In addition, it is of course possible to mount other filters in addition to the metal fabric type photocatalyst filter in the photocatalyst filter module or other parts of the pollutant purifier.

Hereinafter, preferred embodiments of the present invention and effects according to the examples and comparative examples will be described, but the present invention is not limited thereto.

Example 1

Step 1: Preparation of metal fabric

Austenitic stainless steel SUS304, 0.04mm in diameter wire was applied as warp and weft to woven at a density of 10*10 picks/mm ² and porosity of 34% in a rapier loom.

Step 2: primary heat treatment step

The stainless steel fabric woven in step 1 was cut into a square shape of 600*600 mm suitable for a filter module, immersed in 10 wt% citric acid diluent for 30 minutes to remove impurities, washed with deionized water, and dried. The prepared stainless steel fabric was placed in a heat treatment furnace heated to 800°C where air was naturally supplied, treated for 2 hours, and then taken out and quenched by circulating air at room temperature.

Step 3: Forming the titanium dioxide coating layer by chemical vapor deposition

A general organometallic chemical vapor deposition method was applied.

Heated titanium precursor titanium tetra-isopropoxide (Titanium tetra-isopropoxide, TTIP) 0.1 mol / L concentration was added for 1 hour with oxygen using a nitrogen carrier gas at a rate of 50ml / min. In the deposition step, the surface temperature of the stainless steel fabric was maintained at 400° C., the pressure was maintained at 10 torr or less, and the exhaust gas and the byproduct vapor phase precursor were removed from the cold trap.

Step 4: Second heat treatment step

The titanium dioxide coating layer-forming metal fabric prepared in step 3 was doped by heat diffusion in an air heat treatment furnace at 400° C. for 1 hour or more, and then naturally cooled.

Comparative Example 1

A metal fabric photocatalyst filter was manufactured in the same manner as in Example 1, except that the first heat treatment step of Step 2 was omitted.

Comparative Example 2

A metal fabric photocatalyst filter was manufactured in the same manner as in Example 1, except that the second heat treatment step of Step 4 was omitted.

Comparative Example 3

A metal fabric-type photocatalyst filter was manufactured in the same manner as in Example 1, except that the heat treatment temperature of Step 4 was changed to 800°C.

In step 2 of Example 1, the surface of the stainless steel fabric was analyzed before and after the first heat treatment, and the results are shown in FIGS. 3 and 4. In the X-ray diffraction analysis pattern of FIG. 3, the crystal lattice peak of the iron (γFe) component appeared on the surface of stainless steel before the first heat treatment, but after the first heat treatment, the metal oxide component of Cr ² O ³ and Fe ² O ³ It can be found that the peak of. 4(a) shows the analysis of the shape of the surface before and after the first heat treatment with a scanning electron microscope (SEM), which has a smooth surface before the first heat treatment, but a thick metal oxide in a rough form after the first heat treatment. You can see that it is fulfilling. In (b) of FIG. 4, the weight ratio of each metal oxide generated after heat treatment was calculated by a scanning electron microscope-energy dispersion analysis method (SEM-EDX method) to analyze the components of the metal oxide additionally formed on the surface before and after the first heat treatment. . It can be seen that Cr ² O ³ is actively formed due to an increase in the content of the chromium element, and Fe ² O ³ and NiO are also partially formed on the surface of the stainless steel fabric.

On the other hand, in order to compare the crystal structure of the titanium dioxide coating layer formed according to the temperature during chemical vapor deposition, in step 3 of Example 1, a glass substrate was used instead of the stainless steel fabric and only the process temperatures were 250, 300, 350, 400, 450 A titanium dioxide coating layer was formed by chemical vapor deposition while variously adjusting to ℃. The results of X-ray diffraction analysis of each prepared sample are shown in FIG. 5(a), and the surface change observed by a scanning electron microscope (SEM) is shown in FIG. 5(b), and an atomic microscope (AFM) is used. The analyzed flatness (RMS Roughness) is shown in Fig. 5(c). From (a) of FIG. 5, as the process temperature increases, the peak gradually becomes sharper and the crystal structure grows, but at a process temperature of 450°C, the anatase crystal structure peak (100,200) rapidly changes to the rutile crystal structure 112. You can see that it is. This is consistent with the observation result of the scanning electron microscope of FIG. 5(b), and it can be estimated that the particles form small crystals at a process temperature of 400 to 440° C., resulting in a uniform and specific crystal structure with a large specific surface area. . From (c) of FIG. 5, which is a result of analyzing the flatness, which is an index of the specific surface area, which directly affects the photocatalytic activity, it was found that the flatness increases as the temperature rises and shows a value of 10 nm or more at 400°C. .

In addition, for Example 1 and each comparative example, the absorbance and photocatalytic activity of the titanium dioxide coating layer formed on the stainless steel fabric under ultraviolet irradiation were compared. The absorbance of the entire ultraviolet-visible region is compared and shown in FIG. 6(a), and the photocatalytic activity is calculated by measuring the concentration change at which the organic material nitrobenzene is decomposed under the condition of the representative wavelength of ultraviolet A (365 nm). It is shown in Fig. 6 (b). The sample of Example 1 according to the present invention showed very light absorption and contaminant removal ability at a wavelength (315 to 400 nm) in the ultraviolet A region, and also showed a significant light absorption improvement in the visible wavelength region.

Claims (9)

(S1) preparing a metal fabric made of stainless steel wire having a chromium content of 15% by weight or more;
(S2) increasing the chromium oxide content on the surface of the metal fabric to 50% by weight or more by first heat-treating the metal fabric at a temperature of 600 to 800°C;
(S3) forming a titanium dioxide coating layer on the surface of the high-temperature heat-treated metal fabric using chemical vapor deposition at 400 to 440°C; And
(S4) A method of manufacturing a metal fabric type photocatalyst filter comprising the step of secondary heat treatment of a metal fabric on which the titanium dioxide coating layer is formed at a temperature of 400 to 500 °C. According to claim 1,
The average diameter of the stainless steel wire is 0.035 to 1.0 mm, the method of manufacturing a metal fabric type photocatalyst filter, characterized in that the porosity of the metal fabric is 30% or more. delete delete A metal fabric type photocatalyst filter formed according to the method of claim 1. A filter unit comprising the metal fabric type photocatalyst filter of claim 5; And
A photocatalyst filter module comprising a light source unit equipped with a light emitting diode lamp for irradiating ultraviolet rays to the metal fabric type photocatalyst filter. The method of claim 6,
The photocatalyst filter module further comprises a honeycomb structure passage unit that guides contaminants through the filter unit uniformly. A purifier comprising the photocatalyst filter module of claim 6. The method of claim 8,
The purifier is a contaminant purifier, characterized in that the air purifier.

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