KR20220041639A - Method for producing activated carbon coated with visible light catalyst - Google Patents

Abstract

The present application relates to a manufacturing method of activated carbon comprising a visible light-activated catalyst, and more specifically, to a manufacturing method of activated carbon comprising a visible light-activated catalyst, which attaches the visible light active catalyst to a surface of activated carbon by spraying a coating solution comprising the visible light active catalyst at a predetermined concentration and maintains the original deodorization performance of activated carbon while minimizing the loss rate of the visible light-activated catalyst during a process.

Description

Method for producing activated carbon coated with visible light active catalyst

The present application relates to a method for producing activated carbon coated with a visible light active catalyst, and by spraying a coating solution containing a visible light active catalyst at a predetermined concentration to attach it to the surface of the activated carbon, while minimizing the loss rate of the visible light active catalyst during the process, the nature of activated carbon It relates to a method for producing a visible light-activated catalyst-coated activated carbon that can maintain the deodorizing performance of the.

The necessity of an air purifier is gradually increasing as indoor and air pollution intensifies. In addition, air purifier regulations (standards) are also increasing in line with rising consumer demands.

Activated carbon, the main material of deodorizing filters provided in air purifiers, has a high specific surface area that appears through various pores with nano or micro sizes, and harmful gases (VOCs), heavy metals, bacteria, adsorbs viruses. For this purpose, it is very important that the adsorbent has a high specific surface area. This is because the high specific surface area of an adsorbent has a close relationship with the saturated adsorption amount and adsorption rate of the adsorbent. In addition, it is possible to improve the adsorption property of the material to be removed by attaching a specific functional group to the surface of the adsorbent through surface treatment of the adsorbent.

However, since activated carbon is an adsorbent, when the adsorbable sites (pores) are saturated, the performance deteriorates rapidly, and in particular, it is difficult to adsorb an aldehyde-based gas. Therefore, a chemical adsorption type organic additive is introduced to remove aldehyde-based gas. Research on a deodorizing method with excellent deodorization performance without falling off is required.

According to an embodiment of the present application, by spraying a coating solution containing a visible light active catalyst at a predetermined concentration to attach to the surface of the activated carbon, while minimizing the loss rate of the visible light active catalyst during the process, the original deodorizing performance of activated carbon can be maintained. An object of the present invention is to provide a method for producing activated carbon including a visible light activated catalyst.

One aspect of the present application relates to activated carbon containing a visible light active catalyst.

As an example, as visible light-activated catalyst-coated activated carbon, 1 g of activated carbon is put into a 10 L chamber containing at least one evaluation target gas selected from the group consisting of 10 ppm of formaldehyde, 10 ppm of ammonia, and 10 ppm of toluene, and the evaluation target In the removal performance (CADR) evaluation experiment for removing gas, the reduction rate of the removal performance of the activated carbon coated with visible light that satisfies the following relation 1 may be 5% or less.

[Relational Expression 1]

Performance degradation rate (%) = [Removal of activated carbon before coating - Removal of activated carbon after coating] × 100 / Removal of activated carbon before coating

(However, the removal performance refers to the removal rate (CADR, m3/hr) for the evaluation target gas of 10 ppm of 1 g of activated carbon when a module including a fan generating a wind speed of 1.7 m/s in a 10 L chamber is operated)

As an example, the removal performance of 1 g of activated carbon with respect to 10 ppm of formaldehyde may be 1.3 to 1.5 m 3 /hr.

As an example, the removal performance of 1 g of activated carbon with respect to 10 ppm of ammonia may be 0.7 to 1.5 m 3 /hr.

As an example, the removal performance of 1 g of activated carbon with respect to 10 ppm of toluene may be 2.0 to 2.3 m 3 /hr.

As an example, the visible light active catalyst may include platinum-supported tungsten oxide.

As an example, the content of platinum relative to 100 parts by weight of tungsten oxide may be 0.01 parts by weight to 5 parts by weight.

As an example, the weight ratio of the visible light active catalyst to the activated carbon may be 0.5 to 5 parts by weight: 99.5 to 95 parts by weight.

One aspect of the present application relates to a method for producing activated carbon.

As an example, the preparation method comprises the steps of preparing a coating solution containing a visible light active catalyst; spraying the coating solution on activated carbon; and drying the activated carbon sprayed with the visible light activated catalyst.

As an example, the visible light active catalyst may be included in the coating solution at a concentration of 5 to 70% by weight.

As an example, the coating solution may contain 5 to 70% by weight of the visible light active catalyst.

As an example, the weight ratio of the visible light active catalyst to the activated carbon may be 0.5 to 5 parts by weight: 99.5 to 95 parts by weight.

According to an embodiment of the present application, the visible light catalyst is sprayed only on the surface of the activated carbon without contact with other devices through spraying at high temperature (about 100 ° C.), thereby greatly reducing the loss rate of the visible light activated catalyst that occurs during the manufacturing process of activated carbon It is possible to provide a method for producing activated carbon comprising a visible light-activated catalyst capable of

According to an embodiment of the present application, since it can be coated while preventing the loss of various chemicals (adhesives) attached to the activated carbon using a minimum amount of water, a visible light-activated catalyst capable of minimizing the degradation rate of the activated carbon is included. A method for producing activated carbon can be provided.

According to an embodiment of the present application, it is possible to provide a method for producing activated carbon including a visible light-activated catalyst with greatly improved deodorization performance.

According to an embodiment of the present application, it is possible to provide a method for producing activated carbon including a visible light-activated catalyst capable of responding to various production conditions, such as lab scale, pilot scale, and mass production.

1 is a flowchart for explaining a method of manufacturing activated carbon according to an embodiment of the present application.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that the features, components, etc. described in the specification are present, and one or more other features or components may not be present or may be added. Doesn't mean there isn't.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

In the present application, the term “nano” may mean a size of nanometers (nm), for example, may mean a size of 1 to 1,000 nm, but is not limited thereto. In addition, in the present specification, the term "nanoparticles" may mean particles having an average particle diameter of nanometers (nm), for example, may mean particles having an average particle diameter of 1 to 1,000 nm, It is not limited.

Activated carbon can be applied to deodorizing filters used in air purifiers. Activated carbon can be removed by adsorbing harmful substances through various pores on the surface. On the other hand, there is a problem in that the removal performance is reduced as the pores are included as the adsorbed harmful substances.

The deodorizing filter is a corrugated type filter that is advantageous for shape processing because activated carbon is coated on paper, but has poor deodorization performance. It is a honeycomb type filter that is somewhat advantageous in deodorization performance but is difficult to shape the filter by cooking activated carbon powder and processing it into pellets. , There is a combi-type filter capable of realizing high performance in the form of inserting activated carbon powder between the dust collector and the support. In the case of a corrugated filter, a visible light-activated catalyst can be coated after the filter is manufactured, but in the case of a combi filter, since activated carbon enters the filter, it is difficult to properly coat the visible light-activated catalyst on the surface of the activated carbon. Therefore, there is a need for a method capable of effectively coating a visible light active catalyst on the surface of the activated carbon powder before processing the filter fabric, and an embodiment of the present application provides a solution to this problem.

In one example, the production method of the present application is a method of effectively coating a visible light active catalyst on the surface of the activated carbon powder used for manufacturing the combi filter, and through this method, the activated carbon itself is It is possible to realize the effect of maintaining the deodorizing performance that it has.

Hereinafter, the activated carbon of the present application and a manufacturing method thereof will be described in detail with reference to the accompanying drawings. However, the accompanying drawings are exemplary, and the scope of the activated carbon of the present application and its manufacturing method is not limited by the accompanying drawings.

Activated carbon can adsorb harmful gases, heavy metals, bacteria, viruses, etc. due to its high specific surface area and various functional groups (adhesives) on the surface appearing through various pores having nano or micro sizes. The high specific surface area of an adsorbent has a close relationship with the adsorbent's saturated adsorption amount and adsorption rate. In addition, the adsorption property of the target material can be improved by attaching a specific functional group to the surface of the adsorbent through surface treatment of the adsorbent. However, since activated carbon itself is an adsorbent, if the adsorbable site is saturated, the performance may decrease. Accordingly, the present applicant intends to provide activated carbon to which a visible light-activated catalyst is attached.

In general, a method for coating a specific material on activated carbon is to coat the above-mentioned adhesive. The additive is to coat the pores of the activated carbon with a chemical that is highly reactive with a specific gas. After adding the activated carbon to the solution in which the additive is dissolved and stirring it sufficiently, the filtrate is separated and the activated carbon is dried using a dip-coating method. use it However, in this method, a significant amount of loss is generated, and since the visible light-activated catalyst is relatively expensive, a large loss rate provides a great economic disadvantage to the coating of the visible light-activated catalyst. In addition, since the visible light-activated catalyst is coated on activated carbon already coated with an additive, when an additive is added to the solution as described above, the additive is dissolved by water and the deodorization performance may be rather reduced.

In order to solve this problem, the present applicant follows a method of coating by directly applying (spraying) a coating solution containing a visible light active catalyst of a predetermined concentration on the surface of the activated carbon.

Activated carbon is a porous carbon material including micropores and has very high adsorption properties. The activated carbon is a very effective deodorizing material in terms of price and performance. The activated carbon can remove harmful gases through adsorbable sites (pores) as an adsorbent.

In order not to saturate the activated carbon, it can be regenerated by decomposing the harmful gas adsorbed by the visible light-activated catalyst particles. In addition, by including the visible light-activated catalyst, it is possible to improve the gas adsorption performance of the activated carbon itself, and in particular, it can improve the removal performance for formaldehyde, toluene, and ammonia.

Visible light active catalyst is a material that can clean air, deodorize and antibacterial by generating surface active oxygen such as superoxide anion or hydroxy radical by electrons and holes generated from energy obtained by absorbing light. For example, the superoxide anion or hydroxy radical generated by the photoactive action of the composite particles can decompose harmful substances such as acetaldehyde, ammonia, formaldehyde, acetic acid, TVOC, etc., and Antibacterial action against bacteria is possible.

Here, the weight ratio of the visible light active catalyst to the activated carbon may be 0.5 to 5 parts by weight: 99.5 to 95 parts by weight.

In addition, the visible light active catalyst is a composite particle including platinum particles and tungsten oxide particles, and the composite particles are formed in a form in which nano-sized platinum particles are supported on the surface of the tungsten oxide particles.

The tungsten oxide particles may be formed into spherical, plate-shaped or needle-shaped particles by, for example, a sol-gel method or a hydrothermal method as a carrier, but the shape is not limited.

Tungsten oxide particles have excellent visible light activation performance. The platinum particles may be supported on the porous metal oxide by a photo-deposition method, but is not limited thereto. The platinum particles act as a co-catalyst to facilitate separation of electrons and holes from energy obtained by absorbing light.

As an example, the content of platinum relative to 100 parts by weight of tungsten oxide may be 0.01 parts by weight to 5 parts by weight. By controlling their content in a weight ratio within the above range, the tungsten oxide particles sufficiently generate electrons and holes by visible light while sufficiently preventing recombination of electrons and holes generated by the platinum particles to effectively improve photocatalytic activity efficiency. there is.

When the content of the tungsten oxide particles exceeds the content range, electrons and holes generated by visible light can easily recombine, and it is difficult to separate them, so that sufficient photocatalytic activity is not exhibited. When the content is less than the content range, the tungsten oxide Since the number of electrons transferred from the particles is not sufficiently secured, there is a risk that the photocatalytic activity may be lowered, and the photocatalytic performance may be deteriorated due to a decrease in the area exposed to light of the tungsten oxide particles.

In addition, the specific surface area of the tungsten oxide particles may be about 50 m 2 /g to about 500 m 2 /g. By having a high level of specific surface area within the above range, it can be effectively exposed to a light source such as visible light, and the porosity can be formed at an appropriate level to sufficiently support the platinum particles.

As an example, 1 g of activated carbon is put into a 100 L chamber containing at least one evaluation target gas selected from the group consisting of 10 ppm of formaldehyde, 10 ppm of ammonia, and 10 ppm of toluene, and the removal performance of removing the target gas ( CADR) in the evaluation experiment, the reduction rate of the removal performance of the activated carbon coated with visible light that satisfies the following Relational Equation 1 may be 5% or less.

[Relational Expression 1]

Performance degradation rate (%) = [Removal of activated carbon before coating - Removal of activated carbon after coating] × 100 / Removal of activated carbon before coating

However, the removal performance refers to the removal rate (CADR, m3/hr) for the evaluation target gas of 10 ppm of 1 g of activated carbon when the module including a fan generating a wind speed of 1.7 m/s in a 10 L chamber is operated. In addition, in the evaluation, the temperature range is 25° C. and the humidity is 55%. The evaluation is based on real-time measured data using FT-IR.

In the experiment on 1 g of activated carbon, the removal performance for formaldehyde 10 ppm gas was 1.3-1.5 ㎥/hr, the removal performance for ammonia 10 ppm gas was 0.7-0.8 ㎥/hr, and the removal performance for toluene 10 ppm gas was 2.0- It may be activated carbon which is 2.3 m3/hr.

The deodorization performance evaluation applies a method for evaluating the CADR of activated carbon, and a 100-liter chamber for evaluation, FR-IR and activated carbon powder loading for detecting the real-time concentration of the chamber are possible, and a small size using a mounted fan Deodorization performance evaluation can be performed using an evaluation device composed of a jig that can produce the same effect as an air purifier.

1 is a flowchart for explaining a method of manufacturing activated carbon according to an embodiment of the present application.

As shown in Figure 1, the manufacturing method comprises the steps of preparing a coating solution containing a visible light active catalyst at a predetermined concentration (S10); It may include a step of spraying the coating solution on the activated carbon (S20) and drying the activated carbon sprayed with a visible light active catalyst (S30).

By applying the method of spraying the visible light active catalyst, the loss rate and initial performance degradation can be improved by minimizing the water used for coating, and the drying time can be greatly shortened.

The apparatus used for coating is not particularly limited, but may be composed of a compounding machine for preparing a coating solution, a spray nozzle capable of spraying the same, and a coating machine capable of stirring and drying the activated carbon powder. Contrary to the conventional method of injecting the activated carbon powder into the coating solution, the coating solution is uniformly sprayed onto the stirred activated carbon powder through a spray nozzle.

In particular, the coating machine can be applied in various shapes such as cylindrical, cylindrical, circular, and the like, and the size of the coating machine can also be applied in various sizes according to purposes such as lab scale, pilot scale, mass production, etc.

Hereinafter, each step of the manufacturing method will be described in more detail.

First, a coating solution containing a visible light active catalyst at a predetermined concentration is prepared (S10).

As described above, the visible light active catalyst preferably includes platinum-supported tungsten oxide.

As an example, the coating solution may contain 5 to 70% by weight of the visible light active catalyst.

The coating solution may be prepared at a concentration of 5 to 70 wt% depending on the type of nozzle and coater. After adding a certain amount of water to the blender, a visible light-activated catalyst is added, and the mixture is stirred for 30 minutes to 1 hour.

Then, the coating solution is sprayed on the activated carbon (S20).

In general, the visible light-activated catalyst may be prepared as an aqueous slurry or a slurry in which a binder is mixed, and then coated on the deodorizing filter by various methods such as dip coating, spray coating, and the like. The present application takes a method of spraying directly on activated carbon rather than coating it on a deodorizing filter. On a deodorizing filter equipped with activated carbon, for example, compared with the conventional technique of applying a visible light active catalyst to one side of the substrate, it is possible to implement a low deodorization performance degradation rate while maintaining the deodorization performance.

As an example, the weight ratio of the visible light-activated catalyst and the activated carbon may be 3:97.

Through this weight ratio, it is possible to prevent deterioration of the initial performance of the activated carbon.

After putting the activated carbon into the coating machine, stirring is performed to the extent that the shape of the activated carbon powder is not deformed, and the temperature of the coating machine is raised to an appropriate temperature between 60 and 150 degrees through a jacket installed in the coating machine, and then stirred for 30 minutes. A stabilization process is performed.

The coating solution is directly sprayed on the surface of the activated carbon being stirred through the spray nozzle connected to one side of the compounder.

And, it may include a step (S30) of drying the activated carbon sprayed with the visible light active catalyst.

After spraying the coating solution, the activated carbon is recovered while stirring for 1 to 5 hours while maintaining the temperature for drying.

In the activated carbon prepared by this manufacturing process, the weight ratio of the visible light active catalyst and the activated carbon may be 0.5 to 5 parts by weight: 99.5 to 95 parts by weight.

Hereinafter, the present application will be described in more detail through experimental examples.

[Experimental example]

It was attempted to confirm the loss rate and coating uniformity of the visible light-activated catalyst through component analysis using ICP.

[Example 1]

A visible light-activated catalyst was added to water at a concentration of 20% and stirred for 30 minutes to prepare a coating solution. After 10 kg of activated carbon was put into the coater, the coater jacket temperature was fixed at 100°C. When the temperature of the activated carbon was stabilized, the coating solution was sprayed onto the agitated activated carbon through a spray nozzle. After spraying the coating solution, the activated carbon sample was collected with ground bran for 10 minutes, the moisture content was measured, and drying was terminated when the moisture content of the activated carbon became the same as before coating, to prepare a sample of Example 1.

[Examples 2 and 3]

Examples 2 and 3 samples were prepared by adding a visible light active catalyst at concentrations of 40% and 60%, and performing coating in the same manner as in Example 1.

[Comparative Example 1]

Samples of activated carbon without visible light active catalyst used to prepare Examples 1 to 3.

[Comparative Example 2]

A visible light-activated catalyst was added to water at a concentration of 20%, and activated carbon powder was added to the coating solution according to the dip-coating method, followed by stirring for a sufficient time. After the stirring was completed, the filtrate was separated and discharged, and the remaining activated carbon powder was recovered and dried in a dryer at 100 degrees. After confirming the moisture content, drying was terminated to prepare a comparative example 2 sample.

[Comparative Example 3]

A sample of Comparative Example 3 was prepared by adding a visible light active catalyst at a concentration of 3% and coating in the same manner as in Example 1.

[Evaluation 1]

In order to confirm the maintenance of the performance of activated carbon, CADR, which is the deodorization performance of formaldehyde, ammonia, and toluene, was evaluated as follows using a chamber of 100 liters and FT-IR for Examples 1 to 3 and Comparative Examples 1 to 3 and the results are shown in Table 1 below.

formaldehyde
Deodorization performance (㎥/hr) ammonia
Deodorization performance (㎥/hr) toluene
Deodorization performance (㎥/hr) Loss rate (%) Example 1 1.38 0.78 2.11 9 Example 2 1.42 0.81 2.19 16 Example 3 1.41 0.80 2.21 25 Comparative Example 1 1.44 0.81 2.20 - Comparative Example 2 1.02 0.71 2.13 30 Comparative Example 3 1.14 0.73 2.19 19

As shown in Table 1, it was confirmed that the loss rate and deodorization performance of the activated carbon powder prepared by using the spray injection of the present application were superior to those of Comparative Examples. This is because the coating solution is sprayed only on the activated carbon and it can minimize the contact of the coating solution with equipment other than the activated carbon (for example, the outer wall). can do.

[Evaluation 2]

After obtaining the average value of each deodorizing performance shown in Table 1, the performance degradation rate was calculated based on the average value of Comparative Example 1 and shown in Table 2 below.

Average deodorization performance degradation rate (%) Example 1 4.04 Example 2 0.67 Example 3 0.67 Comparative Example 1 - Comparative Example 2 13.25 Comparative Example 3 8.76

As shown in Table 2, compared to Comparative Examples 2 to 3, Examples 1 to 3 coated by the method of the present application showed a performance degradation rate of less than 5% compared to the activated carbon before coating. In addition, the higher the concentration of the coating solution, the higher the loss rate, but it was confirmed that it was advantageous in terms of maintaining the deodorizing performance. This is because, by minimizing the water used for coating, it is possible to minimize the loss of already deposited chemicals. On the other hand, in the case of toluene, which is dependent on physical adsorption, in the conventional dip-coating method, the performance degradation was not large, whereas in the case of other gases that depend on the additive, it was confirmed that the performance degradation was large.

Although the above has been described with reference to preferred embodiments of the present application, those skilled in the art can variously modify and change the present application without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that you can.

Claims (11)

A visible light activated catalyst coated activated carbon comprising:
A removal performance (CADR) evaluation experiment in which 1 g of activated carbon is put into a 10 L chamber containing at least one evaluation target gas selected from the group consisting of formaldehyde 10 ppm, ammonia 10 ppm, and toluene 10 ppm and the target gas is removed In, activated carbon having a reduction rate of 5% or less of the removal performance of the activated carbon coated with a visible light that satisfies the following relational expression (1).
[Relational Expression 1]
Performance degradation rate (%) = [Removal of activated carbon before coating - Removal of activated carbon after coating] × 100 / Removal of activated carbon before coating
(However, the removal performance refers to the removal rate (CADR, m ³ /hr) for the evaluation target gas of 10 ppm of 1 g of activated carbon when a module including a fan generating a wind speed of 1.7 m/s in a 10 L chamber is operated. )
The method of claim 1,
The removal performance of 1 g of activated carbon with respect to 10 ppm of formaldehyde is 1.3 to 1.5 m 3 /hr of activated carbon.
The method of claim 1,
The removal performance of 1 g of activated carbon with respect to 10 ppm of ammonia is 0.7 to 1.5 m 3 /hr of activated carbon.
The method of claim 1,
The removal performance of 1 g of activated carbon with respect to 10 ppm of toluene is 2.0 to 2.3 m 3 /hr of activated carbon.
The method of claim 1,
The visible light active catalyst is activated carbon containing platinum-supported tungsten oxide.
6. The method of claim 5,
The content of platinum relative to 100 parts by weight of tungsten oxide is 0.01 parts by weight to 5 parts by weight of activated carbon.
The method of claim 1,
The weight ratio of the visible light active catalyst to the activated carbon is 0.5 to 5 parts by weight: 99.5 to 95 parts by weight of activated carbon.
Preparing a coating solution containing a visible light active catalyst;
spraying the coating solution on activated carbon; and
A method for producing activated carbon comprising the step of drying the activated carbon sprayed with a visible light activated catalyst.
9. The method of claim 8,
Visible light active catalyst is a method for producing activated carbon contained in the coating solution at a concentration of 5 to 70% by weight.
9. The method of claim 8,
The coating solution is a method for producing activated carbon comprising a visible light active catalyst in an amount of 5 to 70% by weight.
9. The method of claim 8,
The weight ratio of the visible light active catalyst to the activated carbon is 0.5 to 5 parts by weight: 99.5 to 95 parts by weight of the method for producing activated carbon.

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