KR20210064846A - Activated carbon formed from raw materials including fly ash and method for producing same - Google Patents

Abstract

Disclosed is an activated carbon formed by carbonizing and activating a raw material including pitch, and fly ash surface-modified with a carbonyl group. In the activated carbon and a manufacturing method thereof provided in one aspect of the present invention, fly ash introduced into the activated carbon serves as a catalyst to improve the performance of the activated carbon, and the carbonyl group introduced into the fly ash helps in pore formation, thereby increasing the specific surface area, and being able to manufacture the activated carbon including fly ash that can be applied to waste treatment by using industrial waste petroleum residue and fly ash.

Description

Activated carbon formed from raw materials including fly ash and method for producing same

The present invention relates to activated carbon formed from a raw material containing fly ash and a method for manufacturing the same.

As the importance of indoor air quality has been highlighted, research on the development of technologies to remove various harmful substances in the air is in full swing. Among these, harmful substances such as sulfur oxides, nitrogen oxides, and volatile organic compounds generated in exhaust gas enter the interior of the vehicle and cause health problems and safety accidents for drivers. As a method for removing these harmful gases, an adsorption method through activated carbon is mainly used.

Activated carbon is a porous carbon material containing a large number of micropores, and is used to improve indoor air quality, advanced water purification treatment in water purification plants, and adsorption filters in household water purifiers. In order to improve the lifespan of the activated carbon and to improve the removal efficiency of harmful substances, a method of introducing a metal or a metal oxide is mainly used.

For example, Korean Patent Registration No. 10-1845175 relates to an activated carbon material for an inner filter of an automobile treated with alkali metal and a method for manufacturing the same, by dissolving activated carbon and an alkali metal precursor or an alkaline earth metal precursor in distilled water and mixing them. preparing a solution; preparing a first stirring solution by stirring the mixed solution at room temperature; adding an acid catalyst to the first stirring solution; preparing a second stirring solution by stirring the first stirring solution to which the acid catalyst is added at room temperature; and filtering and drying the second stirring solution to prepare alkali metal oxide-activated carbon or alkaline earth metal oxide-activated carbon, Alkali-based metal-treated activated carbon material for automobile internal filter manufacturing method disclosed are doing

In addition, Korean Patent Registration No. 10-1721493 discloses a) manufacturing a carbide by carbonizing a vegetable organic material; and b) mixing the carbide with a metal oxide and then activating the activated carbon; discloses a method for producing activated carbon and activated carbon prepared therefrom.

The above-mentioned registered patents 10-1845175 and 10-1721493, which are conventionally developed technologies, provide a process for introducing a metal oxide into activated carbon, and the patent uses a process of mixing a metal oxide precursor and activated carbon. This process is a process of introducing a metal oxide to the surface of the prepared activated carbon, and the introduced metal oxide blocks pores of the activated carbon, so that the performance of the activated carbon is deteriorated.

Accordingly, there is a need for a new activated carbon manufacturing process to solve the problems of the prior art.

It is an object of the present invention to provide an activated carbon prepared by using fly ash having a carbonyl group formed therein and a method for producing the same.

In order to achieve the above object, in one aspect of the present invention

pitch; and

fly ash surface-modified with a carbonyl group;

There is provided an activated carbon formed by carbonizing and activating a raw material comprising a.

In addition, in another aspect of the present invention

forming a carbonyl group on the surface of fly ash;

mixing the fly ash with pitch and an activator; and

carbonizing and activating the mixed mixture;

There is provided a method for producing activated carbon comprising a.

In addition, in another aspect of the present invention

An adsorbent comprising the activated carbon is provided.

Furthermore, in another aspect of the present invention

contacting sulfur oxide with the adsorbent;

There is provided a method for removing sulfur oxides comprising a.

Activated carbon provided in one aspect of the present invention and a method for producing the same, fly ash introduced into the activated carbon plays a catalytic role to improve the performance of the activated carbon, and the carbonyl group introduced into the fly ash helps in pore formation to increase the specific surface area There is an effect that can produce activated carbon containing fly ash that can be applied to waste treatment by using industrial waste petroleum residue and fly ash.

1 is a flow chart showing a method for producing activated carbon containing fly ash according to an embodiment of the present invention;
2 is a graph showing the XPS analysis results of the surface-treated fly ash of Examples 1, 2, 3 and Comparative Example 1 of the present invention;
3 is a graph showing the results of subdividing the C1s peak among the XPS results of the surface-treated fly ash of Examples 1, 2, 3 and Comparative Example 1 of the present invention;
4 is a graph showing the nitrogen adsorption isotherms of the activated carbons of Examples 1, 2, 3, Comparative Examples 1 and 2 of the present invention;
5 is a graph showing the sulfur dioxide removal characteristics of the activated carbon of Examples 1, 2, 3, Comparative Examples 1 and 2 of the present invention;
6 is a graph showing the amount of sulfur dioxide that can be removed per 1 g of activated carbon of Examples 1, 2, 3, Comparative Examples 1 and 2 of the present invention.

Since the present invention can make various changes and thus various embodiments can be made, specific embodiments will be presented below and described in detail.

In addition, all terms in this specification that are not specifically defined may be used in a meaning that is understandable to all those of ordinary skill in the art to which the present invention belongs.

However, it should be understood that the present invention is not intended to be limited only to the specific embodiments to be described below, and includes all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Accordingly, there may be other equivalents and modifications to the embodiments described herein, and the embodiments presented herein are only the most preferred embodiments.

In one aspect of the invention

pitch; and

fly ash surface-modified with a carbonyl group;

There is provided an activated carbon formed by carbonizing and activating a raw material comprising a.

Hereinafter, the activated carbon provided in one aspect of the present invention will be described in detail for each configuration.

First, the activated carbon provided in one aspect of the present invention is

It is prepared from raw materials containing fly ash surface-modified with pitch and carbonyl groups.

The pitch may be at least one selected from the group consisting of petroleum pitch, petroleum pitch, and mixtures thereof.

The fly ash surface-modified with the carbonyl group may be formed by treating the fly ash with a carboxylic acid.

The fly ash may be a by-product from coal-fired power plants.

The fly ash contains a large number of metal oxides, which can be introduced into the activated carbon to induce a catalytic effect of the metal oxides on the activated carbon.

The conventional method of introducing a metal oxide to the surface of the activated carbon blocks the pores of the activated carbon and lowers the performance of the activated carbon. In the method of adding a metal oxide during the activated carbon manufacturing process, it is difficult to exert the catalytic effect because the metal oxide is present inside the activated carbon. there was On the other hand, in the activated carbon provided in one aspect of the present invention, fly ash having a carbonyl group introduced therein is added to the activated carbon manufacturing process, the carbonyl group introduced into the fly ash during the activation process forms pores, and the formed pores form the fly ash inside It serves as a passage for exposure to the outside, making it easy to exert the catalytic effect of the metal oxide contained in fly ash. In addition, the carbonyl group introduced into fly ash forms additional pores to increase the specific surface area of activated carbon, and it can be attributed to waste treatment by utilizing petroleum residues, a by-product of the petroleum refining process, and fly ash, a by-product of coal-fired power plants. have.

The fly ash particle size of the raw material is preferably 10 μm to 100 μm, more preferably 15 μm to 60 μm, and most preferably 30 μm to 60 μm. If the particle size of the fly ash is less than 10 μm, there is a problem that is not economical because the actual efficiency is not large, and when it exceeds 100 μm, there is a problem in that the catalytic activity of the fly ash is reduced.

In the fly ash, as the carbonyl group is formed, the amount of the oxygen functional group is relatively increased, and impurities such as calcium, sodium, fluorine, and sulfur may be relatively decreased.

The raw material may further include an activator.

The activator may be at least one selected from the group consisting of KOH, NaOH, CaCO ₃ , HPO _{4 and mixtures thereof.}

The content of fly ash in the raw material may be 1 wt% to 20 wt%, may be 2 wt% to 10 wt%, and may be 3 wt% to 8 wt%.

In addition, the activated carbon provided in one aspect of the present invention is formed by carbonizing and activating a raw material.

The carbonization and activation may be performed simultaneously.

The activated carbon provided in one aspect of the present invention preferably has a ^{specific surface area of 1000 m 2} /g or more, the volume of micropores may be 0.3 cm ³ /g or more, and the total pore volume is 0.4 cm ³ /g or more. and the microporosity may be 80% or more.

In another aspect of the invention

Forming a carbonyl group on the surface of fly ash (S100);

mixing the fly ash with pitch and an activator (S210); and

carbonizing and activating the mixed mixture (S220);

There is provided a method for producing activated carbon comprising a.

Hereinafter, the method for producing activated carbon provided in another aspect of the present invention will be described in detail for each step.

First, the method for producing activated carbon provided in another aspect of the present invention includes the step of forming a carbonyl group on the surface of fly ash (S100).

In the above step, the average particle diameter of the fly ash may be preferably 10 μm to 100 μm. It is more preferably 15 μm to 60 μm, and most preferably 30 μm to 60 μm. If the average particle diameter of the fly ash is less than 10 μm, there is a problem that is not economical because the actual efficiency is not large, and when it exceeds 100 μm, there is a problem in that the catalytic activity of the fly ash is reduced.

The step may further include the step of pulverizing the fly ash (S110) for the uniformity of the fly ash.

The powdering step (S110) may be performed using a cutter, a grinder, a crusher, and the like, and may be performed without being limited thereto, as long as it is an apparatus or method capable of reducing the particle size of fly ash.

The step of forming a carbonyl group on the surface of the fly ash may include contacting the fly ash with a carboxylic acid (S120).

The carboxylic acid may be malic acid.

The weight ratio of the fly ash and the carboxylic acid may be 10:1 to 1:5. Preferably it may be 5:1 to 1:3, and more preferably 2:1 to 1:2.

When the amount of the carboxylic acid added is less than 0.1 times compared to fly ash, there is a problem in that sufficient carbonyl groups are not introduced to the fly ash surface, and when it exceeds 5 times, the practical efficiency is not large, so there is a problem that is not economical.

The step of contacting the fly ash with carboxylic acid (S120) is preferably made at 40 °C to 100 °C, more preferably at 60 °C to 95 °C, and most preferably at 70 °C to 90 °C. If the reaction temperature is less than 40 ℃, there is a problem that the carbonyl group is not introduced to the surface of the fly ash because the temperature required for the reaction is not sufficient, and when it exceeds 100 ℃, the solvent water evaporates and a uniform surface reaction does not occur there is a problem.

The reaction time for the step (S120) is preferably made for 30 minutes to 300 minutes, more preferably made for 60 minutes to 240 minutes, and most preferably made for 120 minutes to 180 minutes. If the reaction time is less than 30 minutes, there is a problem that the carbonyl group is not introduced to the fly ash surface because the reaction time is not sufficient, and when it exceeds 300 minutes, the practical efficiency is not large, so there is an economical problem.

Next, the method for producing activated carbon provided in another aspect of the present invention includes mixing the fly ash with pitch and an activator (S210).

The above step performs grinding and mixing at the same time, and may be performed using a grinder, crusher, etc., and if it is an apparatus or method capable of simultaneously performing grinding and mixing of pitch, fly ash, and an activator, it is not limited thereto. can

The pitch may be at least one selected from the group consisting of petroleum pitch, petroleum pitch, and mixtures thereof.

The softening point of the pitch is preferably 50 °C to 200 °C, more preferably 70 °C to 150 °C, and most preferably 100 °C to 130 °C. If the softening point of the pitch is less than 50 ℃, there is a problem that the yield after activation is low, which is not economical, and if it exceeds 200 ℃, there is a difficulty in manufacturing activated carbon having a high specific surface area because activation is not made.

The activator may be at least one selected from the group consisting of KOH, NaOH, CaCO ₃ , HPO _{4 and mixtures thereof.}

Next, the method for producing activated carbon provided in another aspect of the present invention includes carbonizing and activating the mixed mixture (S220).

In the above step, the carbonization and activation may be performed simultaneously.

The above step may be performed through heat treatment in an inert gas atmosphere at a temperature of 500° C. to 1000° C. for 10 minutes to 300 minutes.

It is preferably from 500°C to 1000°C, more preferably from 700°C to 950°C, and most preferably from 750°C to 900°C. In addition, it is preferably carried out for 10 minutes to 300 minutes, more preferably carried out for 30 minutes to 240 minutes, and most preferably carried out for 40 minutes to 180 minutes. If the reaction temperature is less than 500 °C or the reaction time is less than 10 minutes, sufficient activation is not made, so it is difficult to prepare activated carbon with a high specific surface area, and when the reaction temperature exceeds 1000 °C or the reaction time is 300 minutes If it exceeds, overactivation occurs and the generated pores collapse, resulting in a decrease in specific surface area and yield.

The method for producing activated carbon provided in another aspect of the present invention uses fly ash, a by-product of coal-fired power generation, which is composed of various metal oxides, but is discarded due to little use, to reduce the process cost, and to use fly ash in the activated carbon manufacturing process. The addition method is introduced to prevent clogging of the pores of the activated carbon, to increase the specific surface area of the activated carbon by creating a passage for the activity of the internally added fly ash, and to increase the activity of the internally added fly ash. manufacturing can be made possible.

In another aspect of the present invention

An adsorbent comprising the activated carbon is provided.

The adsorbent may adsorb and remove harmful gas, for example, it may be a sulfur oxide gas, and more specifically, it may remove sulfur dioxide gas.

The adsorbent includes the activated carbon. In addition to the presence of fly ash in the activated carbon, there is a passage connected to the outside, so that the catalytic effect of the metal oxide contained in the fly ash can be exerted, so that excellent adsorption performance is obtained. can have

In another aspect of the invention

contacting sulfur oxide with the adsorbent;

There is provided a method for removing sulfur oxides comprising a.

In the method for producing sulfur oxides, sulfur oxide is brought into contact with the adsorbent, and fly ash is present in the activated carbon contained in the adsorbent, and there is a passage connecting to the outside, a metal oxide catalyst contained in fly ash Since the effect can be exhibited, the sulfur oxide removal performance may be superior to that of the conventional method.

Hereinafter, the present invention will be described in more detail through Examples and Experimental Examples. The scope of the present invention is not limited to specific embodiments, and should be construed by the appended claims. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

<Example 1>

In order to prepare the activated carbon containing fly ash, petroleum-based pitch having a softening point of 120 °C was selected as the raw material of the activated carbon, and KOH was selected as the activator. The particle size of the fly ash was adjusted so that the average particle size was 50 μm using a ball mill. Fly ash was added to an aqueous solution in which malic acid was dissolved in a weight ratio of 1:1 between malic acid and fly ash of which the particle size was adjusted, and then treated at 90° C. for 180 minutes, and then washed with distilled water to remove unreacted malic acid. The malic acid-treated fly ash was dried at 100° C. for 5 hours to prepare fly ash having a carbonyl group introduced thereto.

Fly ash, pitch, and an activator having a carbonyl group introduced therein were mixed in a ratio of 1: 10: 10, respectively, and then pulverized and mixed using an electric mixer for 10 minutes. After the mixture was added to the alumina boat, carbonization and activation were simultaneously performed at 750° C. for 3 hours in an inert gas atmosphere. After the activation was completed, the sample was washed with distilled water to remove the unreacted activator, and then dried at 100° C. for 24 hours to prepare activated carbon containing fly ash.

<Example 2>

Activated carbon containing fly ash was prepared in the same manner as in Example 1, except that in Example 1, an aqueous solution in which malic acid was dissolved in a weight ratio of 0.5:1 to malic acid was used.

<Example 3>

Activated carbon containing fly ash was prepared in the same manner as in Example 1, except that in Example 1, an aqueous solution in which malic acid was dissolved in a weight ratio of 2:1 to malic acid was used.

<Comparative Example 1>

Activated carbon containing fly ash was prepared in the same manner as in Example 1, except that the malic acid treatment process was not performed in Example 1.

<Comparative Example 2>

Comparison was performed by selecting using commercially available activated carbon showing pore properties similar to those of Example 1.

<Experimental Example 1> Fly ash surface functional group characteristics according to malic acid treatment method

The surface functional groups of the malic acid-treated fly ash in Examples 1 to 3 and Comparative Example 1 were measured using X-ray photoelectron spectroscopy (XPS), and the results are shown in FIG. 2 and Table 1. .

Sample name Atomic ratio (at%) C O Si Al Ca Fe Example 1 25.9 49.9 18.9 4.1 0.3 0.9 Example 2 33.2 45.4 16.2 4.2 0.3 0.7 Example 3 20.1 54.7 20.4 3.7 0.2 0.9 Comparative Example 1 35.7 45.2 12.6 4.5 1.1 0.9

As shown in FIG. 2 and Table 1, as the amount of malic acid increased, the amount of oxygen functional groups included in fly ash tended to increase, and compared with Comparative Example 1 in which malic acid was not treated, calcium, sodium, It was confirmed that impurities such as fluorine and sulfur were reduced.

In order to more precisely confirm the characteristics of the oxygen functional group introduced into the fly ash, the C1s peak of the XPS result was subdivided and analyzed, which is shown in FIG. 3 and Table 2. As the amount of malic acid increased, the alcohol and carbonyl groups of fly ash tended to increase, and in particular, the carbonyl groups were 0.4% in Comparative Example 1 without malic acid treatment, whereas 6.1% in Example 1 and 6.1% in Example 3 case, it increased very high to 6.7%.

bonding structure binding energy content Example 1 Example 2 Example 3 Comparative Example 1 C(1) C-C, C-H 285.0 76.8 78.0 76.7 79.4 C(2) C-O 286.5 13.9 13.5 14.4 12.8 C(3) C=O 288.0 6.1 2.4 6.7 0.4 C(4) Carbonate 289.4 3.1 6.1 2.2 7.5

<Experimental Example 2> Pore properties of activated carbon containing fly ash

The pore properties and specific surface areas of the activated carbon containing fly ash prepared in Examples 1 to 3 and Comparative Example 1 and the commercially available activated carbon of Comparative Example 2 were evaluated using a nitrogen adsorption isotherm, and are shown in FIG. 4 . The specific surface area and pore characteristics were calculated based on the nitrogen adsorption isotherm results, and the results are shown in Table 3 below.

Sample name Specific surface area (m ² /g) Micropore volume (cm ³ /g) Total pore volume (cm ³ /g) Microporosity (%) Example 1 1216.8 0.444 0.507 83.9 Example 2 1006.7 0.367 0.424 86.6 Example 3 1170.8 0.424 0.485 87.6 Comparative Example 1 847.5 0.312 0.372 87.4 Comparative Example 2 1236.4 0.298 0.504 59.1

As shown in FIG. 4 and Table 3, the specific surface area of Example 1 was 1216.8 m ² /g, showing the highest specific surface area, and the ratio of micropores was also the highest at 87.6%. For embodiments the ratio of malic low Example 2. The specific surface area was found with the lowest specific surface area of the 1006.7 m ² / g to the embodiment were lower than in Example 1, in the case of Comparative Example 1 that are not acid treated 847.5 m ² / g . On the other hand, in the case of Example 3 having a high malic acid ratio, the ^{specific surface area was 1207.8 m 2} /g, similar to that of Example 1. This increase in specific surface area is considered to be a result of the carbonyl group introduced to the malic acid surface forming pores during the activation process as shown in FIG. 2 and Table 2, and the pores created by the carbonyl group have the pore size of micropores. It is believed to be It was confirmed that the commercial activated carbon of Comparative Example 2 had a specific surface area of ^{1236.4 m 2 /g similar to that of Example 1.}

<Experimental Example 3> Noxious gas removal characteristics of activated carbon containing fly ash

In order to evaluate the harmful gas removal characteristics of the activated carbon containing fly ash prepared in Examples 1 to 3 and Comparative Examples 1 to 2, SO ₂ gas removal performance was evaluated. SO ₂ gas removal performance was evaluated by measuring the amount of _{adsorbed SO 2} gas after adding 0.5 g of sample to a 6.2 cc reactor and then _{injecting 40 ppm of SO 2} gas at 25° C. at a flow rate of 500 cc/min. did. The SO ₂ gas removal performance is shown in FIG. 4, and the removal rate per unit g of the sample is calculated from the _{SO 2 gas removal graph, and is shown in FIG. 5 .}

_{5 and 6, the SO 2} gas removal rate of the activated carbon containing fly ash prepared in Example 1 _{was the highest, and the SO 2} gas removal rate of the activated carbon containing fly ash prepared in Comparative Example 1 This was the lowest. In the case of Comparative Example 1, the introduced fly ash exists inside the activated carbon, but there is no passage connected to the outside, so the catalytic effect of the metal oxide contained in the fly ash cannot be exerted, so it is considered that the SO ₂ gas removal rate is the lowest. In the case of the commercial activated carbon of Comparative Example 2, the pore properties and specific surface area were similar to those of Example 1, but in the case of Example 1, there was a catalytic effect by fly ash, so it is considered that the SO ₂ gas removal rate was high.

Claims (12)

pitch; and
fly ash surface-modified with a carbonyl group;
Activated carbon formed by carbonizing and activating a raw material containing a.
According to claim 1,
Activated carbon, characterized in that the raw material further comprises an activator.
According to claim 1,
Activated carbon, characterized in that the activated carbon has a specific surface area ^{of 1000 m 2 /g or more.}
forming a carbonyl group on the surface of fly ash;
mixing the fly ash with pitch and an activator; and
carbonizing and activating the mixed mixture;
A method for producing activated carbon comprising a.
5. The method of claim 4,
The method for producing activated carbon, characterized in that the average particle diameter of the fly ash of forming a carbonyl group on the surface of the fly ash is 10 μm to 100 μm.
5. The method of claim 4,
The step of forming a carbonyl group on the surface of the fly ash
A method for producing activated carbon comprising the step of contacting fly ash with a carboxylic acid.
7. The method of claim 6,
The carboxylic acid is a method for producing activated carbon, characterized in that malic acid (malic acid).
7. The method of claim 6,
The method for producing activated carbon, characterized in that the weight ratio of the fly ash and the carboxylic acid is 10:1 to 1:5.
5. The method of claim 4,
The pitch is at least one selected from the group consisting of petroleum pitch, petroleum pitch, and mixtures thereof,
The activator is KOH, NaOH, CaCO ₃ , HPO ₄ A method for producing activated carbon, characterized in that at least one selected from the group consisting of and mixtures thereof.
5. The method of claim 4,
Carbonizing and activating the mixed mixture is a method for producing activated carbon, characterized in that performed for 10 minutes to 300 minutes at a temperature of 500 ℃ to 1000 ℃.
An adsorbent comprising the activated carbon of claim 1.
Contacting the adsorbent of claim 11 with sulfur oxide;
A method for removing sulfur oxides comprising a.

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