KR20170127683A - Regenerable adsorbent and method for producing same - Google Patents

Abstract

The present invention relates to an adsorbent for removing malodors and volatile organic compounds, and a method of producing the same, and more specifically, to a continuous regenerable adsorbent capable of maintaining adsorption capacity over continuous regeneration; and to a method of producing the same. According to the present invention, when adsorbing malodors and volatile organic compounds, an activated carbon support containing multiple pores induces diffusion of the corresponding gas molecules. Further, a boehmite catalyst coated on the surface of the activated carbon support forms an ionic (or covalent) bond with the corresponding gas molecules, wherein the ionic (or covalent) bond formed by the boehmite catalyst has an adsorption strength which is stronger than physical adsorption, yet weaker than chemical adsorption, such that the adsorbed gas molecules are easily detached during the adsorbent regeneration process. Furthermore, the surface of the adsorbent after the regeneration process is restored to its initial state, thereby making the continuous adsorption possible.

Description

TECHNICAL FIELD [0001] The present invention relates to a regenerated adsorbent,

The present invention relates to an adsorbent for removing odor and volatile organic compounds and a method for producing the same. More particularly, the present invention relates to a repetitive regenerable adsorbent capable of maintaining adsorption performance even in repetitive regeneration, and a method for producing the same.

As the industry becomes more sophisticated and the use of automobiles and various paint materials increases, the structure of pollution sources is changing and the kinds of air pollutants are also diversified. In particular, Volatile Organic Compounds (VOCs) have detrimental effects on human health and the environment and have long been regarded as air pollutants.

Volatile Organic Compounds (VOCs) are a generic term for liquid or gaseous organic compounds that are easily evaporated into the atmosphere because of their high vapor pressure. They are very diverse and wide-ranging, producing thousands of chemical substances and being highly flammable, It also causes accidents.

Organic compounds including BTEX (Benzene, Toluene, Ethylbenzene, Xylene) and PCE, TCE, CHC, halogen and non-halogenated chlorine are the main materials of volatile organic compounds. Regulation is absolutely necessary with this high compound and economical control method is urgently required.

In addition, volatile organic compounds are known to be highly contagious substances that have high mobility in the atmosphere and cause odors as well as anesthesia. In addition, it has potential toxicity and carcinogenicity, and photochemically reacts with nitric oxide and other chemical compounds in the air to form photochemical oxidizing substances such as ozone to form photochemical smog. It is a reality.

At present, volatile organic compounds are used in air degassing process, hazardous waste incineration facility, chemical product manufacturing, textile product manufacturing, fertilizer manufacturing facility, biological wastewater treatment facility, carbon regeneration facility, urban soil landfill site, dry cleaning facility, degreasing facility, Facilities, and food industries. Volatile organic compounds, such as toluene, acetone, and methyl ethyl ketone (MEK), released from workplaces, cause discomfort and resistance to nearby residents at low concentrations and cause long-term exposure at high concentrations. It causes. Management of odor-causing substances is essential as the distance from the workplace is reduced due to the expansion of the housing area. Effective removal of volatile organic compounds, which are inevitably discharged at the operating stage, is very important to producers in terms of reducing environmental burden.

Currently, activated carbon adsorbents are used in adsorption towers or deodorization filters in workplaces where odorous and volatile organic compounds are emitted. In order to reuse the activated carbon adsorbent, a high temperature of 500 ° C or higher was required in an inert atmosphere such as nitrogen gas. However, when the regeneration process described above is repeatedly carried out, deterioration due to heat treatment proceeds to deteriorate the physical properties (for example, specific surface area, pore volume, etc.) of the activated carbon and deteriorate the adsorption performance.

In order to solve this problem, the heat treatment was carried out at a relatively low temperature (150 to 200 ° C.), but the carbon surface of the activated carbon was chemically bonded to the adsorbed gas. As a result, the specific surface area and pore volume And the tendency that repetitive reuse tends to lower the adsorption selectivity.

Accordingly, recently, studies on adsorbents capable of maintaining the adsorption performance even in repetitive regeneration have been actively conducted.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a repetitive regenerable adsorbent capable of maintaining adsorption performance even in repetitive regeneration and a method for producing the same.

In order to achieve the above-mentioned object, the repetitive regenerable adsorbent according to the present invention includes an activated carbon support and a boehmite catalyst.

The boehmite type catalyst of the repetitive regenerable adsorbent for mainly removing the toluene component includes boehmite, iron chloride and ammonium phosphate.

The boehmite type catalyst of the repetitive regenerable adsorbent for mainly removing the acetaldehyde component includes boehmite, iron chloride, manganese chloride, and sodium borohydride.

The boehmite type catalyst of the repetitive regenerable adsorbent for mainly removing the ammonia component includes boehmite, iron chloride, manganese chloride, and phosphoric acid.

The boehmite type catalyst of the repetitive regenerable adsorbent mainly for removing the hydrogen sulfide component includes boehmite, iron chloride, and copper chloride.

Meanwhile, a method of producing a repetitive regenerable adsorbent according to the present invention includes a first step of preparing activated carbon as a support, a second step of preparing a boehmite catalyst in an aqueous solution state, a step of mixing the activated carbon and the boehmite catalyst A third step, and a fourth step of drying the mixed activated carbon and the boehmite catalyst.

According to the present invention configured as described above, since the gas molecules bound to the ionic (or coordination) bond to the boehmite catalyst are easily removed during the regeneration process, the adsorbent used for adsorbing odor and volatile organic compounds can be effectively regenerated . In addition, since the surface of the adsorbent having undergone the regeneration process is restored to the initial state, the adsorption performance can be maintained even with repeated regeneration.

Therefore, it is economical to reduce the cost of periodically replacing the adsorbent, and it is possible to prevent environmental pollution caused by the adsorbent which is discarded after use.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are graphs showing the adsorption performance of a toluene component over time according to Example 1 and Comparative Example 1 of the present invention. FIG.
3 and 4 are graphs showing the adsorption performance of acetaldehyde component over time according to Example 2 and Comparative Example 2 of the present invention.
5 and 6 are graphs showing the adsorption performance of ammonia components over time according to Example 3 and Comparative Example 3 of the present invention.
7 and 8 are graphs showing adsorption performance of hydrogen sulfide components over time according to Example 4 and Comparative Example 4 of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, embodiments of the present invention will be described in detail. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention provides a repetitive regenerated adsorbent which is coated with a boehmite catalyst on the surface of activated carbon, which is a support, to effectively remove odor and volatile organic compounds and can be used repeatedly through a regeneration process.

The repetitive regenerated adsorbent includes activated carbon as a support and a boehmite catalyst coated on the surface of activated carbon.

Activated carbon is a generic name of a porous material containing carbon as a main component, and it is made of a plant such as palm shell, sawdust, wood, coal, and alane, or a fossil plant, or a petroleum pitch.

Activated carbon activation methods include gas activation and drug activation.

The gas activation method is an activation method for carbonizing a raw material to form a pore structure by erosion of the surface of carbon by a gentle oxidation reaction in a high temperature gas atmosphere of 700 to 1,000 ° C. in a weakly oxidizing atmosphere.

The chemical activation method is a method of burning a woody material to which a chemical such as zinc chloride or phosphoric acid is added at 600 to 700 ° C to release hydrogen and oxygen in the raw material by using water vapor or the like to leave carbon of a porous structure.

The activated carbon produced by the above-mentioned method contains 90 to 95% by weight of carbon, which contains a small amount of hydrogen, sulfur, ash and the like, and has many pores. Activated carbon exhibits excellent adsorption due to its highly developed pore structure.

Boehmite type catalysts coated on the surface of activated carbon can be classified into four types according to the components of odor and volatile organic compounds to be removed. When for example, comprises a toluene component of offensive odor and the volatile organic compound it is mainly uses a boehmite-type catalyst containing the ammonium phosphate _{(NH 4 H 2 PO 4)} . In the case of odorous and volatile organic compounds mainly containing acetaldehyde components, a boehmite type catalyst containing manganese (Mn) is used. In the case of odor and volatile organic compounds mainly containing ammonia component, a boehmite type catalyst containing phosphoric acid is used. In addition, a boehmite catalyst containing copper chloride (CuCl ₂ ) is used in the case of malodorous or volatile organic compounds mainly containing hydrogen sulfide components.

The boehmite catalyst for removing the toluene component includes boehmite, iron chloride (FeCl ₂ ), and ammonium phosphate (NH ₄ H ₂ PO ₄ ). At this time, boehmite is 10 wt% based on the weight of activated carbon support, iron chloride is 1 to 5 wt% based on the weight of boehmite, and ammonium phosphate is 1 to 5 wt% based on the weight of boehmite.

The boehmite catalyst for removing the acetaldehyde component includes boehmite, iron chloride (FeCl ₂ ), manganese chloride (MnCl ₂ ) and sodium borohydride (NaBH ₄ ). At this time, the boehmite is 10% by weight based on the weight of the activated carbon support, and the iron chloride is 1 to 5% by weight based on the weight of the boehmite. In addition, manganese chloride is 1 to 5 wt% based on the weight of boehmite, and sodium borohydride is 10 wt% based on the weight of boehmite.

The boehmite catalyst for removing the ammonia component includes boehmite, iron chloride (FeCl ₂ ), and phosphoric acid (H ₂ PO ₄ ). At this time, the boehmite is 10 wt% based on the weight of the activated carbon support, the iron chloride is 1 to 5 wt% of the boehmite weight, and the phosphoric acid is 1 to 5 wt% of the boehmite weight.

The boehmite catalyst for removing the hydrogen sulfide component includes boehmite, iron chloride (FeCl ₂ ), and copper chloride (CuCl). At this time, boehmite is 10 wt% based on the weight of activated carbon support, iron chloride is 1 to 5 wt% based on the weight of boehmite, and copper chloride is 1 to 5 wt% based on the weight of boehmite.

The boehmite-type catalyst having the above-described structure is preferably 10% by weight based on the weight of activated carbon, and is preferably uniformly coated on the surface of activated carbon.

The present invention provides a method of producing an iterative regenerable adsorbent.

A method of producing a repetitive regenerable adsorbent includes a first step of preparing activated carbon as a support, a second step of preparing a boehmite catalyst in an aqueous solution state, a third step of mixing activated carbon and a boehmite catalyst, And a fourth step of drying the activated carbon and the boehmite catalyst.

The adsorbent of the constitution and the production method described above, since the activated carbon which is a support contains a large number of pores, it induces the diffusion of the gas molecules when adsorbing odor and volatile organic compounds. In addition, the boehmite catalyst coated on the surface of the activated carbon support has ion (or coordination) bond with the corresponding gas molecule. At this time, ion (or coordination) bonding by the boehmite catalyst is stronger than physical adsorption and has a weaker adsorption strength than chemical adsorption, so adsorbed gas molecules can be easily desorbed in the process of regenerating the adsorbent. In addition, the surface of the adsorbent that has undergone the regeneration process can be restored to its initial state, which enables repeated adsorption.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the scope of the present invention is not limited to the embodiments shown below.

Example 1. Preparation of adsorbent coated with boehmite type catalyst for removal of toluene component

Activated carbon to be used as a support for the repetitive regenerable adsorbent was prepared. Activated carbon is a pellet type activated carbon having an outer diameter of 3 to 4 mm and a length of 3 to 4 mm. Wash it to remove foreign matter on the surface, dry it at 120 ℃ for 24 hours, seal it in a desiccator and store.

The boehmite was dispersed in deionized water in an amount of 10% by weight based on the weight of activated carbon to prepare a first solution.

To 100 g of deionized water containing 1% by weight of hydrochloric acid, 1 to 5% by weight of transition metal iron based on the weight of boehmite and 1 to 5% by weight of ammonium phosphate based on the weight of boehmite were mixed, and then the mixture was stirred at 200 rpm for 15 minutes Followed by stirring to prepare a second solution.

After the second solution was dispensed into the first solution prepared above, the third solution was prepared by stirring at 200 rpm for 60 minutes at room temperature, 100 g of activated carbon was added to the third solution, mixed and dried A repetitive regenerable adsorbent was prepared. At this time, the drying process is a process of drying at 20 to 40 ° C for 24 hours or more, drying at 80 ° C for 12 hours, and drying at 120 ° C for 12 hours.

Comparative Example 1. Adsorbent without catalyst coating

The adsorbent of Comparative Example 1 is a pellet type activated carbon having an outer diameter of 3 to 4 mm and a length of 3 to 4 mm.

Experimental Example 1. Time-dependent removal performance test of toluene component in odor and volatile organic compounds

Experiments were conducted under the following conditions to confirm the removal performance of the toluene component per adsorbent over time.

6 g of the adsorbent of the above-described Examples and Comparative Examples was placed in the reactor, and the temperature of the reactor was adjusted to room temperature. At this time, the total flow rate of the simulated gas flowing into the reactor was controlled at 1,000 ml / min, and the gas hourly space velocity (GHSV) was maintained at 3,000 hr ^-1 . 50 ~ 400ppm included in the simulated gas was maintained.

Here, the adsorbent of Example 1 was repeated 10 times after adsorption and regeneration, and the adsorbent of Comparative Example 1 was repeated 4 times after adsorption and regeneration.

1 and 2 are graphs showing the removal performance of a toluene component among malodorous and volatile organic compounds according to Experimental Example 1. FIG.

It was confirmed from the above-described Experimental Example 1 that the adsorptive performance of the repeated regenerated adsorbent prepared according to Example 1 of the present invention was maintained even after several adsorption and regeneration processes as shown in FIG. On the other hand, referring to FIG. 2, the adsorption performance of the adsorbent of Comparative Example 1 is remarkably lowered by repeating the adsorption and regeneration processes.

Example 2 Preparation of adsorbent coated with boehmite catalyst for removal of acetaldehyde component

Activated carbon to be used as a support for the repetitive regenerable adsorbent was prepared. Activated carbon is a pellet type activated carbon having an outer diameter of 3 to 4 mm and a length of 3 to 4 mm. Wash it to remove foreign matter on the surface, dry it at 120 ℃ for 24 hours, seal it in a desiccator and store.

The boehmite was dispersed in deionized water in an amount of 10% by weight based on the weight of activated carbon to prepare a first solution.

To 100 g of deionized water containing 1% by weight of hydrochloric acid, 1 to 5% by weight of transition metal iron based on the weight of boehmite and 1 to 5% by weight of manganese chloride relative to the weight of boehmite were mixed, and then the mixture was stirred at 200 rpm for 15 minutes Followed by stirring to prepare a second solution.

The second solution was dropped into the first solution prepared through the above-described procedure, and stirred at 200 rpm at room temperature for 60 minutes. Thereafter, sodium hydroxide of 10% by weight based on the weight of the boehmite was added and stirred at 200 rpm for 30 minutes at room temperature to prepare a third solution.

100 g of activated carbon was added to the third solution and mixed, followed by drying to prepare a repetitive regenerable adsorbent. At this time, the drying process is a process of drying at 20 to 40 ° C for 24 hours or more, drying at 80 ° C for 12 hours, and drying at 120 ° C for 12 hours.

Comparative Example 2. Adsorbent without catalyst coating

The adsorbent of Comparative Example 2 is a pellet type activated carbon having an outer diameter of 3 to 4 mm and a length of 3 to 4 mm.

Experimental Example 2. Time-dependent removal performance test of acetaldehyde component of odorous and volatile organic compounds

Experiments were carried out under the following conditions to confirm the removal performance of acetaldehyde component for each adsorbent over time.

6 g of the adsorbent of the above-described Examples and Comparative Examples was placed in the reactor, and the temperature of the reactor was adjusted to room temperature. At this time, the total flow rate of the simulated gas flowing into the reactor was controlled at 1,000 ml / min, and the gas hourly space velocity (GHSV) was maintained at 3,000 hr ^-1 . 50 ~ 400ppm included in the simulated gas was maintained.

Here, the adsorbent of Example 2 was repeated 10 times after the adsorption and regeneration, and the adsorbent of Comparative Example 2 was repeated twice after adsorption and regeneration.

3 and 4 are graphs showing the removal performance of the acetaldehyde component among the odor and volatile organic compounds according to Experimental Example 2. FIG.

As shown in FIG. 3, the adsorbent of Example 2 of the present invention exhibited adsorption performance even after several adsorption and regeneration processes, as shown in FIG. 3. On the other hand, referring to FIG. 4, the adsorption performance of the adsorbent of Comparative Example 2 is remarkably lowered by repeating the adsorption and regeneration processes.

Example 3 Preparation of Adsorbent Coated with Boehmite Catalyst for Removing Ammonia Component

Activated carbon to be used as a support for the repetitive regenerable adsorbent was prepared. Activated carbon is a pellet type activated carbon having an outer diameter of 3 to 4 mm and a length of 3 to 4 mm. Wash it to remove foreign matter on the surface, dry it at 120 ℃ for 24 hours, seal it in a desiccator and store.

The boehmite was dispersed in deionized water in an amount of 10% by weight based on the weight of activated carbon to prepare a first solution.

To 100 g of deionized water containing 1% by weight of hydrochloric acid, 1 to 5% by weight of transition metal iron based on the weight of boehmite was mixed with 1 to 5% by weight of phosphoric acid based on the weight of boehmite, and the mixture was stirred at 200 rpm at room temperature for 15 minutes A second solution was prepared.

After the second solution was dispensed into the first solution prepared above, the third solution was prepared by stirring at 200 rpm for 60 minutes at room temperature, 100 g of activated carbon was added to the third solution, mixed and dried A repetitive regenerable adsorbent was prepared. At this time, the drying process is a process of drying at 20 to 40 ° C for 24 hours or more, drying at 80 ° C for 12 hours, and drying at 120 ° C for 12 hours.

Comparative Example 3. Adsorbent without catalyst coating

The adsorbent of Comparative Example 3 is a pellet type activated carbon having an outer diameter of 3 to 4 mm and a length of 3 to 4 mm.

Experimental Example 3. Time-dependent removal performance test of ammonia component in odorous and volatile organic compounds

Experiments were carried out under the following conditions to confirm the removal performance of ammonia component by adsorbent over time.

6 g of the adsorbent of the above-described Examples and Comparative Examples was placed in the reactor, and the temperature of the reactor was adjusted to room temperature. At this time, the total flow rate of the simulated gas flowing into the reactor was controlled at 1,000 ml / min, and the gas hourly space velocity (GHSV) was maintained at 3,000 hr ^-1 . 50 ~ 400ppm included in the simulated gas was maintained.

Here, the adsorbent of Example 3 was repeated 10 times after the adsorption and regeneration, and the adsorbent of Comparative Example 3 was repeated 3 times after adsorption and regeneration.

5 and 6 are graphs showing the removal performance of the ammonia component in the malodorous and volatile organic compounds according to Experimental Example 3. FIG.

As shown in FIG. 5, the adsorption performance of the repeated regenerated adsorbent prepared according to Example 3 of the present invention was maintained even after several adsorption and regeneration processes. On the other hand, referring to FIG. 6, it can be seen that adsorption performance of the adsorbent of Comparative Example 3 is remarkably lowered by repeating the adsorption and regeneration processes.

Example 4. Preparation of adsorbent coated with boehmite catalyst for removal of hydrogen sulfide component

Activated carbon to be used as a support for the repetitive regenerable adsorbent was prepared. Activated carbon is a pellet type activated carbon having an outer diameter of 3 to 4 mm and a length of 3 to 4 mm. Wash it to remove foreign matter on the surface, dry it at 120 ℃ for 24 hours, seal it in a desiccator and store.

The boehmite was dispersed in deionized water in an amount of 10% by weight based on the weight of activated carbon to prepare a first solution.

1 to 5% by weight of transition metal iron and 1 to 5% by weight of boehmite are mixed with 100 g of deionized water containing 1% by weight of hydrochloric acid and boehmite is mixed with copper chloride at room temperature for 15 minutes at 200 rpm Followed by stirring to prepare a second solution.

After the second solution was dispensed into the first solution prepared above, the third solution was prepared by stirring at 200 rpm for 60 minutes at room temperature, 100 g of activated carbon was added to the third solution, mixed and dried A repetitive regenerable adsorbent was prepared. At this time, the drying process is a process of drying at 20 to 40 ° C for 24 hours or more, drying at 80 ° C for 12 hours, and drying at 120 ° C for 12 hours.

Comparative Example 4. Adsorbent without catalyst coating

The adsorbent of Comparative Example 4 is pellet type activated carbon having an outer diameter of 3 to 4 mm and a length of 3 to 4 mm.

Experimental Example 4. Time-dependent removal performance test of hydrogen sulfide components in odorous and volatile organic compounds

Experiments were conducted under the following conditions in order to confirm the removal performance of the hydrogen sulfide component for each adsorbent over time.

6 g of the adsorbent of the above-described Examples and Comparative Examples was placed in the reactor, and the temperature of the reactor was adjusted to room temperature. At this time, the total flow rate of the simulated gas flowing into the reactor was controlled at 1,000 ml / min, and the gas hourly space velocity (GHSV) was maintained at 3,000 hr ^-1 . 50 ~ 400ppm included in the simulated gas was maintained.

Here, the adsorbent of Example 4 was repeated 10 times after the adsorption and regeneration, and the adsorbent of Comparative Example 4 was repeated twice after the adsorption and regeneration.

FIGS. 7 and 8 are graphs showing the removal performance of the hydrogen sulfide component among the odorous and volatile organic compounds according to Experimental Example 4. FIG.

It was confirmed from the above Experimental Example 4 that the adsorbent performance of the repeated regenerated adsorbent produced according to Example 4 of the present invention was maintained even after several adsorption and regeneration processes as shown in FIG. On the other hand, referring to FIG. 8, it can be seen that the adsorption performance of the adsorbent of Comparative Example 4 is remarkably lowered by repeating the adsorption and regeneration processes.

While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Those skilled in the art will understand. Therefore, the scope of protection of the present invention should be construed not only in the specific embodiments but also in the scope of claims, and all technical ideas within the scope of the same shall be construed as being included in the scope of the present invention.

Claims (15)

A repetitive regenerable adsorbent comprising an activated carbon support and a boehmite catalyst.
The method according to claim 1,
Wherein the boehmite type catalyst comprises boehmite, iron chloride, and ammonium phosphate.
The method of claim 2,
Wherein the boehmite is 10 wt% based on the weight of the activated carbon support, the iron chloride is 1 to 5 wt% of the boehmite weight, and the ammonium phosphate is 1 to 5 wt% of the boehmite weight. Type adsorbent.
The method according to claim 1,
Wherein the boehmite type catalyst comprises boehmite, iron chloride, manganese chloride, and sodium borohydride.
The method of claim 4,
Wherein the boehmite is 10 wt% based on the weight of the activated carbon support, the iron chloride is 1-5 wt% based on the boehmite weight, the manganese chloride is 1-5 wt% based on the weight of the boehmite, Is 10 wt% based on the weight of the boehmite.
The method according to claim 1,
Wherein the boehmite type catalyst comprises boehmite, iron chloride and phosphoric acid.
The method of claim 6,
Wherein the boehmite is 10 wt% based on the weight of the activated carbon support, the iron chloride is 1 to 5 wt% based on the weight of the boehmite, and the phosphoric acid is 1 to 5 wt% absorbent.
The method according to claim 1,
Wherein the boehmite type catalyst comprises boehmite, iron chloride, and copper chloride.
The method of claim 6,
Wherein the boehmite is 10 wt% based on the weight of the activated carbon support, the iron chloride is 1 to 5 wt% based on the boehmite weight, and the copper chloride is 1 to 5 wt% based on the weight of the boehmite. Type adsorbent.
A first step of preparing activated carbon;
A second step of preparing a boehmite catalyst aqueous solution;
A third step of mixing the activated carbon and the boehmite type catalyst aqueous solution; And
And a fourth step of drying the mixed activated carbon and the boehmite type catalyst.
The method of claim 10,
In the first step,
A step 1-1 of washing activated carbon,
And drying the washed activated carbon at 120 ° C. for 24 hours.
The method of claim 10,
In the second step,
A second step of preparing a first solution by dispersing 10 wt% of boehmite in deionized water based on the weight of activated carbon;
At least one of ammonium chloride, ammonium phosphate, manganese chloride, phosphoric acid and copper chloride is added to deionized water containing 1 wt% of hydrochloric acid based on the boehmite weight in an amount of 1 to 5 wt% % To prepare a second solution; And
And (2-3) dripping the second solution into the first solution to prepare a third solution.
The method of claim 12,
Wherein the step 2-2 further comprises mixing 10 wt% sodium borohydride with respect to boehmite weight.
The method of claim 12,
And stirring the second solution at 200 rpm at room temperature for 15 minutes.
The method of claim 12,
And stirring the third solution at normal temperature and 200 rpm for 60 minutes.

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