KR102659329B1 - Impregnated activated carbon and manufacturing method thereof - Google Patents

Abstract

The present invention relates to impregnated activated carbon and a method for manufacturing the same, and can provide activated carbon that has excellent adsorption properties for aldehydes (formaldehyde, acetaldehyde), which are classified as harmful gases, and is resistant to moisture. The activated carbon according to the present invention increases the harmful gas deodorization efficiency compared to existing commercial activated carbon by mixing water repellent and an inorganic antibacterial agent with activated carbon carrying an impregnating material, and can increase the lifespan of activated carbon by suppressing moisture and reducing odor emissions even when used for a long period of time. there is. Additionally, air quality can be expected to improve through the use of impregnated activated carbon.

Description

Impregnated activated carbon and manufacturing method thereof}

The present invention relates to impregnated activated carbon and a method for producing the same, and specifically to activated carbon in which the impregnated material is evenly dispersed by acid treatment and negative pressure treatment, and a method for producing the same.

Air purification filters used for vehicles, purifiers, air conditioning, etc. include particle filters that remove particulate contaminants using filtration fibers, combination filters in which adsorption material is added to the particle filters, and There are antibacterial filters that add the function of inhibiting the growth of bacteria such as mold. Air purification filters for vehicles, purifiers, and air conditioning are used in air conditioning systems to block gaseous pollutants flowing in from the outside. Recently, as awareness of indoor air quality has increased, interest in and demand for composite filters has increased. I'm doing it. Existing commercialized composite filters made of adsorption material composed of activated carbon as a single component are capable of removing various complex harmful gases, such as ammonia, amines, aldehydes (acetaldehyde, formaldehyde), and VOCs (benzene, toluene, xylene, n -Butane, etc.), ozone, organic acids (formic acid, acetic acid, etc.), sulfuric acid, nitric acid, hydrochloric acid, etc. It is impossible to effectively purify air containing gaseous pollutants. This is because the removal mechanism by the adsorbent is different depending on the type of gaseous pollutant. Among the gases to be removed, volatile organic substances such as VOC can generally be removed through the micropores of activated carbon due to their large molecular weight. In the case of acidic gases or basic gases, unlike VOCs, their molecular weight is small, so the amount that can be removed by physical adsorption, such as adsorption through the micropores of activated carbon, is minimal. In order to improve the removal efficiency of acidic gases or basic gases and the service life of the filter, an adsorbent having a functional group that can be removed through a chemical adsorption route must be used. For this purpose, impregnated activated carbon, in which chemical functional groups are added to activated carbon, is used. The simplest and most widely used method to impart chemical functional groups to activated carbon is the impregnation method. However, the impregnation method has the disadvantage that it is not easy to control the size, amount, and distribution of the impregnating material depending on variables such as temperature, time, and drying, and because it is deposited in a single layer only on the surface of activated carbon, the amount of support is small and there is a limit to the amount of support. In addition, there is a problem in that it is difficult to increase the amount of adsorbent beyond a certain ratio to increase the adsorption amount.

Registered Patent Publication No. 10-2062258

In order to solve the above problems, the present invention seeks to provide activated carbon carrying an impregnating material with an amine group and a method for producing the activated carbon.

In addition, it is intended to provide a filter containing the activated carbon.

In order to achieve the above object, the present invention provides impregnated activated carbon and a method for producing the same.

The impregnated activated carbon provided in the present invention is processed by impregnation by mixing a water repellent and an inorganic antibacterial agent on activated carbon carrying an impregnating material with an amine group and vacuum concentrating.

Activated carbon applied to impregnated activated carbon may, for example, have a porous structure and a particle size of 50-3,000㎛. Additionally, the specific surface area of the activated carbon may be 800-3,000 m2/g, preferably 800-2,500 m2/g. If it is less than the specific surface area, performance may deteriorate, and if it exceeds the specific surface area, material costs may increase.

In addition, the activated carbon may have an iodine content of 700 mg/g or more and 3000 mg/g or less, preferably 950 mg/g or more and 2000 mg/g or less, but is not limited thereto. If the iodine value is less than the iodine value, the weight of activated carbon may increase, and if the iodine value is exceeded, the microstructure (2um or less) is not developed, and a meso structure (2um or more) that adsorbs and immediately desorbs harmful gases is developed, leading to a decrease in performance. It can be.

The activated carbon may have a pH of 5 to 7, preferably pH 5.5 to 6.5. In the case of general basic activated carbon, it can be produced through neutralization using one or more acidic solutions among phosphoric acid, sulfuric acid, nitric acid, and hydrochloric acid.

As the impregnating material applied to the impregnated activated carbon, primary amines or sulfonic acids can be used, and representative examples include para-aminobenzoic acid, sulfanilic acid, and tris(hydroxymethyl)aminomethane. )aminomethane), etc., may be used, but are not limited thereto.

The adhesion material may be included in an amount of 0.1 wt% to 40 wt%, preferably 1 wt% to 30 wt%, and more preferably 5 wt% to 20 wt%, based on the weight of activated carbon. If the adhesion material is contained below the above range, gas performance may be reduced, and if contained above the above range, the gas collection performance may be reduced by blocking the pore structure of the activated carbon. Additionally, the adhesion material can be adhesion by dissolving it in a polar solvent or organic solvent.

The activated carbon may additionally contain a water repellent. The water repellent can be used as one or more materials selected from olefin-based, paraffin-based, silicone-based, and fluorine-based materials, and preferably at least one paraffin-based or olefin-based material can be used.

The olefin type may be, for example, polyethylene, but is not limited thereto. The paraffin type may be, for example, paraffin, but is not limited thereto. The silicone-based material may be, for example, a silicone resin, but is not limited thereto. The fluorine type may be, for example, a C6 series fluorine type, but is not limited thereto.

The water repellent may be included in an amount of 0.1 wt% to 20 wt%, preferably 1 to 10 wt%, and more preferably 1 to 5 wt%, based on the weight of activated carbon. If the water repellent is included in less than the above range, the performance of the impregnated component due to moisture adsorption may deteriorate, and if it is included in excess of the above range, the performance of the impregnated activated carbon may be deteriorated.

Additionally, the activated carbon may additionally contain an inorganic antibacterial agent. The inorganic antibacterial agent may be manufactured from one or more materials selected from materials made by replacing metal particles such as silver, copper, zinc, and silicon. 'In accordance with the Act on Safety Management of Household Chemical Products and Biocides, titanium dioxide, silicon dioxide, copper compounds, zinc oxide, silver nitrate, zinc pyrithione, octadecyldimethyl(3-trihydroxysilylpropyl)ammonium chloride is used in a limited amount or less, and specifically, the content may be 0.1 to 20 wt%, preferably 1 to 10 wt%, and more preferably 1 to 5 wt%, based on the weight of activated carbon. If the inorganic antibacterial agent is contained below the above range, it may adhere to the impregnated activated carbon and produce insignificant antibacterial performance. If it is included above the above range, it may not be adhered to the impregnated activated carbon and may be released, failing to meet the standards of the Ministry of Environment.

It is designed to maximize the adsorption and treatment ability of gaseous contaminants while maintaining the amount of adsorbent such as activated carbon of the present invention within a certain range, and is designed to remove gaseous contaminants such as ammonia, aldehydes, VOCs, organic acids, sulfuric acid, nitric acid, and hydrochloric acid. It can be removed simultaneously with excellent removal efficiency, and by mixing an inorganic antibacterial agent and a water repellent, activated carbon that is resistant to moisture and odor can be produced.

The method for producing impregnated activated carbon according to the present invention includes the following steps:

(a) Preprocessing step;

(b) supporting and stirring step;

(c) adhesion step; and

(d) Drying step.

The pretreatment step (a) may optionally include one of a water washing process and a neutralization process, or may include both. The water washing process is to remove dust and foreign substances in the activated carbon, and the neutralization process is to stabilize the reaction of the activated carbon with the impregnating material. One or more acidic solutions among phosphoric acid, sulfuric acid, nitric acid, and hydrochloric acid are added to the activated carbon and dried to obtain a pH of 0 to 7. Preferably, activated carbon with a pH of 5 to 7, more preferably 5.5 to 6.5, is produced.

The (b) supporting and stirring step is an aqueous solution in which 1 wt% to 30 wt% of the additive is dissolved in the activated carbon that has undergone the pretreatment step at a temperature of 95°C or lower, 1 wt to 10 wt% water repellent, and 1 to 10 wt of the additive. % Inorganic antibacterial agent is evenly added to the activated carbon and allowed to soak and stir for some time. The holding and stirring time can be performed for 30 to 120 minutes, preferably 30 to 60 minutes. If the time is less than the above time, the adhesion material/water repellent/inorganic antibacterial agent is not sufficiently stirred and dispersed, and if the time is exceeded, the activated carbon may be crushed into fine powder, causing a pressure increase in the air purifying filter.

The (c) adhesion step is a process of applying negative pressure and heat to the activated carbon after the supporting and stirring steps, and the negative pressure condition can be -0.01 to -0.5, preferably -0.05 to -0.09 MPa. If the negative pressure range is outside the range, the adhesive material may not be applied evenly.

In addition, (d) in the drying step, in the process of applying heat, the temperature is 70 to 200 ℃ or less, preferably 90 to 180 ℃ or less, so that the moisture content of the activated carbon is 5% or less, preferably 1% or less. In order to further minimize the amount of impregnated activated carbon released, 150℃~170℃ is more preferable. If the moisture content is higher than the above, performance may be reduced.

Additionally, the present invention provides a filter containing the activated carbon, and the filter can be used for vehicles, air purifiers, air conditioning filters, etc.

The present invention relates to impregnated activated carbon and a method of manufacturing the same. The impregnated activated carbon obtained by the present invention has the impregnated activated carbon evenly impregnated into the pores of the activated carbon under negative pressure conditions, so that even when the same amount is used, the ability to adsorb and treat pollutants is greatly improved. It can be improved.

Figure 1 shows the manufacturing process of activated carbon according to the present invention.
Figure 2 shows a photograph of the impregnated activated carbon produced by the present invention.
Figure 3 shows the equipment used in the evaluation of Experimental Example 1.
Figure 4 shows a photograph of the air purifier filter of Example 2 according to the present invention.

Hereinafter, the present invention will be described in detail through examples and experimental examples.

However, the following examples and experimental examples only illustrate the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

<Example 1>

(1) Preparation of activated carbon

Activated carbon is a palm-based activated carbon with a porous structure, with a specific surface area of 1,400㎡/g and particle size of No.20~No.100 (0.14mm~0.864mm) based on ASTM MESH.

(2) Manufacturing of washing/neutralized activated carbon

General activated carbon sold commercially has a basic pH of 10 to 11. Therefore, prior to the impregnated activated carbon manufacturing process of the present invention, activated carbon neutralization was performed. 85% phosphoric acid was used in the neutralization process, and general activated carbon with a pH of 5.5 to 6.5 was produced through this neutralization process.

(3) Preparation of mixed solution

As an impregnating material, 10 wt% of para-aminobenzoic acid based on the weight of activated carbon and 2 wt% of water repellent based on the weight of activated carbon were used, and the water repellent included 10-20 wt% of paraffin wax (CAS NO. 8002-74-2) and polyethylene wax (CAS NO. 68441-17-8) A polyethylene wax emulsion containing 10-20 wt% and 3-5 wt% surfactant was used. Additionally, 2 wt% of inorganic antibacterial agent (ZnO powder) was used. A water repellent and an inorganic antibacterial agent were mixed in a 5% aqueous solution of para-aminobenzoic acid dissolved at 95°C.

(4) Production of impregnated activated carbon

The mixed solution was added to the reactor containing the pretreated activated carbon, and the aqueous solution was added to the activated carbon so that it was uniformly dispersed.

<Example 2>

A filter was manufactured using the activated carbon prepared in Example 1. The filter consisted of a carbon layer and a dust collection layer, and after combining powder scatter using a multi-stage press, the final prototype fabric was manufactured using the hot melt method. The manufactured prototype fabric was manufactured using bending and mini-pleating operations.

<Example 3>

Example 1 In the activated carbon manufacturing process, a negative pressure heat treatment process was performed in the drying step. In the process of negative pressure treatment and heat application, activated carbon with a moisture content of 5% or less was manufactured by applying heat at a temperature of 160°C under negative pressure conditions of -0.05 to -0.09 MPa. The prepared activated carbon was manufactured into a filter using the filter manufacturing method of Example 2.

<Comparative Example 1>

General commercially available activated carbon, which is basic, was prepared.

<Comparative Example 2>

Impregnated activated carbon was prepared in the same manner as Example 1, except that the water repellent was not used.

<Comparative Example 3>

A filter was manufactured using only commercially available activated carbon.

<Comparative Example 4>

A filter was manufactured using impregnated activated carbon prepared in the same manner as in Example 1, except that an inorganic antibacterial agent was not used.

<Experimental Example 1>

1. Evaluation of removal efficiency of harmful gas (acetaldehyde)

The performance of the impregnated activated carbon prepared according to the present invention was evaluated. The manufactured activated carbon (Example 1, Comparative Examples 1 and 2) was subjected to performance evaluation using an in-house test method to confirm the harmful gas removal efficiency performance. The self-test evaluation method is to install a non-woven bag containing activated carbon inside a chamber with a size of ^1m3 , which is similar to the internal volume of an actual car, create an atmosphere of more than 15ppm of acetaldehyde in the chamber, and then circulate it with a blower. The removal efficiency of harmful gases was measured. Humidity tests were conducted at 50°C RH and high humidity conditions of 90%RH.

The results are shown in Table 1 below.

test
equipment test
item Target
gas test
sample amount Example 1 Comparative Example 1 Comparative example 2 23℃/50%RH 23℃/90%RH 23℃/50%RH 23℃/50%RH 23℃/90%RH 1m ³ Chamber harmfulness
gas
eliminate
efficiency
(%) acetate
aldehyde 30g 70 65 40 70 55 80g 98 93 73 97 88

Looking at the deodorization efficiency of regular activated carbon and impregnated activated carbon as shown in Table 1, it can be seen that the acetaldehyde deodorization performance improves from 73% to 98% as the impregnating material is applied to the unimpregnated regular activated carbon. In addition, in the case of activated carbon with a water repellent added, the deodorizing performance is 5% higher in high humidity conditions compared to activated carbon without it, showing that the addition of a water repellent reduces the deterioration of deodorizing performance in high humidity conditions.

<Experimental Example 2>

The filters manufactured in Example 2 and Comparative Example 3 were evaluated for performance according to the air purifier deodorization test method according to the SPS-KACA002-132 standard. Test conditions are temperature 23±5℃ and relative humidity 55±15%. The evaluation method is to install a filter (Example 3, Comparative Example 3) manufactured in a household air purifier (model name: LGAS179DWA) inside a chamber of 8m ³ size, and use 5 major gases (ammonia, acetaldehyde, acetic acid, formaldehyde, and toluene) ) to 10ppm in the chamber. The order of measurement was to test a mixture of acetic acid, ammonia, and acetaldehyde, followed by formaldehyde and toluene. The test specimen was operated at the rated wind speed for 30 minutes, the initially injected gas concentration and the residual gas concentration were measured, and the harmful gas removal rate was calculated based on this. The results are shown in Table 2 below.

test equipment Test Items target gas Example 2 Comparative example 3 Test Methods 8m ³ Chamber Deodorization efficiency (%) ammonia 99.99 99.5 SPS-KACA002-0132 acetaldehyde 97.18 51 Acetic acid (acetic acid) 98.81 99.5 formaldehyde 99.99 90 toluene 99.99 99.5

From the experimental results in Table 2 above, the overall adsorption performance is excellent for harmful gases such as ammonia, acetaldehyde, acetic acid, formaldehyde, and toluene, and in particular, the adsorption performance for aldehyde harmful gases such as acetaldehyde and formaldehyde is very excellent. can be seen.

<Experimental Example 3>

An evaluation of the odor effect on the filter to which the impregnated activated carbon manufactured according to the present invention was applied was conducted. The evaluation method was to attach a filter (Example 2, Comparative Example 4) to a home air purifier (model name: LG AS179DWA) and operate the test specimen 24 hours a day for 6 weeks. Experimenters 1 to 6 smelled the vents that were operated once a week and scored according to the criteria. The results are shown in Table 3 below. As shown in Table 3 below, it can be seen that in the case of filters treated with inorganic antibacterial agents, odor generation is reduced when used for a long time.

Test Items Evaluation date <Example 2> <Comparative Example 4> Experimenter 1 Experimenter 2 Experimenter 3 Experimenter 4 Experimenter 5 Experimenter 6 Experimenter 1 Experimenter 2 Experimenter 3 Experimenter 4 Experimenter 5 Experimenter 6 Sensory evaluation Week 1 One One 2 One One 2 2 One 2 One 2 2 Week 2 One One 2 One 2 3 2 One 2 One 3 4 Week 3 2 One 2 One One 2 3 3 3 2 2 3 Week 4 3 One 2 One One 2 4 3 4 3 4 5 Week 5 2 2 One 2 3 3 4 3 4 3 3 5 Week 6 2 3 2 One 2 3 5 4 4 3 4 5 Individual average 1.8 1.5 1.8 1.2 1.7 2.5 3.3 2.5 3.2 2.2 3.0 4.0 overall average 1.8 3.0

Household air purifier filter (gas, odor) impact evaluation standard Odor rating criteria 1st grade There is no smell. level 2 It smells a little, but it's no problem. level 3 Although there is a smell, it is acceptable. level 4 Although it has a strong smell, it is not difficult to tolerate. level 5 It is difficult to tolerate the pungent smell.

<Experimental Example 4>

For the filters to which the impregnated activated carbon manufactured in Example 2 and Example 3 were applied, this test method was performed in accordance with the regulations on standards and methods for testing and inspection of household chemical products subject to safety confirmation due to the use of the inorganic antibacterial agent zinc oxide (ZnO). Based on this, an emission test was conducted. The results are shown in Table 5 below. In the case of filters that were vacuum heat treated at 160°C in this drying process, it can be seen that the amount of zinc oxide released is significantly reduced compared to filters that were not.

Test Items unit The acceptance criteria Test result Test Methods Example 2 Example 3 zinc oxide
Emissions (*) mg 50 or less 40 One Regulations on standards and methods for testing and inspection of household chemical products subject to safety confirmation

<Experimental Example 5>

The acetaldehyde desorption rate was comparatively evaluated for the filters prepared in Example 2 and Comparative Example 4. The test method involves injecting 150 ppm (295 mg) of acetaldehyde into a 1m ³ chamber, then operating a blower equipped with a filter to measure the acetaldehyde gas concentration inside the chamber. The blower was stopped when the final acetaldehyde concentration inside the chamber reached 60 ppm (118 mg). The filters that collected acetaldehyde (Example 2 and Comparative Example 4) were each sealed in a zipper bag.

Reinstall the filter that collected acetaldehyde on the blower inside the 1m ³ chamber and restart the blower. Internal acetaldehyde concentration is measured using FT-IR. The desorbed acetaldehyde was measured and the final desorption rate was calculated, and the results are shown in Table 6 below. As a result of the experiment, in the case of filters to which inorganic antibacterial agent (ZnO) was added, the desorption rate decreased.

Input amount (mg) Adsorption amount (mg) Desorption amount (mg) Desorption rate (%) Example 2 295 177 55 31% Comparative Example 4 295 177 67 58%

Claims (11)

For activated carbon particles with a particle size of No.20~No.100 (diameter 0.14mm~0.864mm) based on ASTM MESH, 5wt%~20wt% of para-aminobenzoic acid as an additive and an inorganic antibacterial agent are used. It contains 1 to 10 wt% of zinc oxide, and 1 wt to 10 wt% of at least one of polyethylene wax and paraffin wax as a water repellent. The activated carbon has a pH of 5.5 to 6.5 and an iodine value of 950 mg/g or more and 2000 mg. /g or less and an impregnated activated carbon characterized in that the moisture content is 5% or less. delete delete delete delete The impregnated activated carbon according to claim 1, wherein the activated carbon has a specific surface area of 800-2,500 m2/g. delete delete A filter comprising the impregnated activated carbon according to claim 1. (a) Preparing particle activated carbon with a particle size of No.20 to No.100 (diameter 0.14mm to 0.864mm) based on ASTM MESH and pretreating the pH to 5.5 to 6.5;
(b) An aqueous solution containing 5 wt% to 20 wt% of the activated carbon, polyethylene wax, and paraffin, with 5 wt% to 20 wt% of the weight of the activated carbon dissolved in the activated carbon that has undergone the pretreatment step at a temperature of 95°C or lower. Adding 1 wt to 10 wt% of at least one water repellent selected from wax-based waxes and 1 to 10 wt% of an inorganic antibacterial agent of zinc oxide evenly into activated carbon and holding and stirring for 30 to 60 minutes;
(c) Adhesion step of negative pressure treatment of -0.05 to -0.09 MPa;
(d) a drying step of applying heat of 90 to 180° C. or lower;
Method for producing impregnated activated carbon comprising. delete