KR102207340B1 - a surface-modified porous carbon composite materials and a method manufacturing the same - Google Patents

Abstract

The present invention relates to a method for producing a porous carbon material having excellent adsorption properties, and more particularly, (a) a diazonium salt having at least one functional group selected from a carboxyl group, a hydroxyl group, a sulfonic acid group, and a phosphoric acid group ( diazonium salt) to modify the surface of the porous carbon material; (b) drying the modified porous carbon material; And (c) irradiating the dried porous carbon material with ultraviolet rays. It relates to a method for producing a porous carbon material having excellent adsorption properties.

Description

Surface-modified porous carbon composite materials and a method manufacturing the same}

The present invention relates to a method for producing a porous carbon material having excellent adsorption properties, and more particularly, (a) a diazonium salt having at least one functional group selected from a carboxyl group, a hydroxyl group, a sulfonic acid group, and a phosphoric acid group ( diazonium salt) to modify the surface of the porous carbon material; (b) drying the modified porous carbon material; And (c) irradiating the dried porous carbon material with ultraviolet rays. It relates to a method for producing a porous carbon material having excellent adsorption properties.

Since the porous carbon material contains a large number of pores inside, it can effectively remove volatile organic compounds, fine dust, viruses, etc., and is widely used in fields such as catalysts, supports, adsorbents, filters, masks, separators, and sensors.

Since the porous carbon material varies in characteristics depending on the size, distribution, and shape of pores contained therein, various studies have been conducted to control the size, distribution, and shape of the pores.

Regarding porous carbon materials, Korean Patent No. 10-1801789 discloses a method of manufacturing a porous carbon material having a high specific surface area.

However, the technology disclosed in the above document cannot meet the demands of consumers who require high-functional carbon materials because the porous carbon material has poor surface properties and thus has inferior harmful gas removal properties, fine dust removal properties, and antibacterial properties.

Korean Patent Registration No. 10-1801789

The present invention is to solve the problems of the prior art, by modifying the surface of a porous carbon material to form a functional group, and by increasing the surface area and porosity, a method for producing a porous carbon material having excellent properties for removing harmful gases and removing fine dust Its purpose is to provide.

In order to achieve the above object, the present invention (a) treats a porous carbon material with a diazonium salt having at least one functional group selected from carboxyl group, hydroxyl group, sulfonic acid group, and phosphoric acid group. Modifying the surface;

(b) drying the modified porous carbon material; And

(c) It provides a method for producing a porous carbon material having excellent adsorption properties, including irradiating the dried porous carbon material with ultraviolet rays.

In one embodiment of the present invention, step (a) is characterized in that 1 to 10 parts by weight of a diazonium salt is used based on 100 parts by weight of the porous carbon material.

In one embodiment of the present invention, the step (b) is characterized in that the modified porous carbon material is dried for 5 to 100 minutes at 30 to 100°C.

In one embodiment of the present invention, step (c) is characterized in that the dried porous carbon material is irradiated with ultraviolet rays for 2 to 30 minutes.

In addition, the present invention provides a porous carbon material having excellent adsorption properties prepared by the above manufacturing method.

In the porous carbon material, a diazonium salt having at least one functional group selected from a carboxyl group, a hydroxyl group, a sulfonic acid group and a phosphoric acid group is graft-polymerized on the surface, and the graft polymer is a hydroxyl group, a carboxyl group, and an ester group by the ultraviolet irradiation. Alternatively, an ether group may be additionally included, and surface roughness, surface area, and porosity of the porous carbon material may be increased by irradiation with ultraviolet rays.

The present invention can provide a method for producing a porous carbon material having excellent properties for removing harmful gases and removing fine dust by modifying the surface of a porous carbon material to form a functional group and increasing the surface area and porosity.

1 shows a scanning electron microscope (SEM) image of a surface-modified porous carbon ball of the present invention.
2 shows adsorption characteristics of porous carbon balls to butane gas according to the concentration of diazonium salt.

The present invention will be described in detail based on the following examples. The terms, examples, etc. used in the present invention are merely exemplified to describe the present invention in more detail and to aid understanding of those skilled in the art, and the scope of the present invention should not be interpreted as being limited thereto.

Technical terms and scientific terms used in the present invention represent the meanings commonly understood by those of ordinary skill in the art, unless otherwise defined.

The present invention comprises the steps of: (a) treating a porous carbon material with a diazonium salt having at least one functional group selected from carboxyl group, hydroxyl group, sulfonic acid group and phosphoric acid group to modify the surface of the porous carbon material; (b) drying the modified porous carbon material; And (c) irradiating the dried porous carbon material with ultraviolet rays. It relates to a method for producing a porous carbon material having excellent adsorption properties.

The step (a) is a step of modifying the surface of the porous carbon material by treating the porous carbon material with a diazonium salt having at least one functional group selected from carboxyl group, hydroxyl group, sulfonic acid group and phosphoric acid group.

Functional groups such as carboxyl group, hydroxyl group, sulfonic acid group, and phosphoric acid group formed on the surface of the porous carbon material through the surface modification can be combined with metals, fine dust or various compounds, and adsorption characteristics, harmful gases and fine dust removal characteristics, Antimicrobial properties and the like can be improved.

The porous carbon material may be graphite, graphite, carbon fiber, carbon nanotube, fullerene, carbon black, carbon paper, carbon balls, carbon particles, etc., and a carbon composite material in which an additive is mixed with the carbon material may also be used. .

The shape of the porous carbon material can be used without limitation, such as a spherical shape, a cylinder shape, and a pellet shape.

The content of the diazonium salt is preferably 1 to 10 parts by weight based on 100 parts by weight of the porous carbon material, and when the content of the diazonium salt is less than 1 part by weight, the introduction of the functional group is insignificant and the adsorption properties are lowered, and when the content exceeds 10 parts by weight, it is prepared. The porosity of the resulting porous carbon material is rather small, so that harmful gases and fine dust cannot be effectively adsorbed.

The diazonium salt may be prepared by reacting an aromatic primary amine having at least one functional group selected from a carboxyl group, a hydroxyl group, a sulfonic acid group and a phosphoric acid group with hydrochloric acid and sodium nitrite.

The diazonium salt is preferably a diazonium salt having a carboxyl group and a diazonium salt having a hydroxyl group at the same time.

The weight ratio of the diazonium salt having a carboxyl group and the diazonium salt having a hydroxyl group is preferably 60 to 80:20 to 40, and when the content range is satisfied, the adsorption property of the porous carbon material is excellent.

As an example, the first step of mixing 1,000 parts by weight of 0.2M HCl into a reaction vessel; A second step of adding 10 to 1,000 parts by weight of 4-aminobenzoic acid or 4-aminophenol to the mixture of the first step and mixing; And 0.1 to 500 parts by weight of 0.02M sodium nitrite to the mixed solution of the second step, and a diazonium salt may be prepared through a third step of mixing.

When the porous carbon material is treated with a diazonium salt having at least one functional group selected from carboxyl group, hydroxyl group, sulfonic acid group and phosphoric acid group, the diazonium salt is continuously bonded to the surface of the porous carbon material, resulting in excellent thermal stability. Can be formed.

When a graft polymer having excellent thermal stability is covalently bonded to the surface of a porous carbon material, the graft polymer is thermally stable and does not decompose even under high temperature conditions such as a coating process and a filter manufacturing process. Antimicrobial properties and the like can be expressed for a long time.

If a low-molecular compound is bonded to the surface of a porous carbon material, the low-molecular compound is easily decomposed and desorbed by heat, and adsorption characteristics, noxious gas removal characteristics, and the like cannot be expressed.

In order to efficiently perform the graft polymerization, a catalyst such as potassium sulfate or sodium nitrate may be used, and the catalyst is preferably used in an amount of 0.01 to 0.1 mol with respect to 1 mol of the diazonium salt. If the content of the catalyst is less than 0.01 mol, the effect of the addition is insignificant, and if it exceeds 0.1 mol, a large amount of a diazonium salt homopolymer is produced, thereby deteriorating the adsorption property.

The graft polymerization is preferably carried out at 50 to 90°C for 10 minutes to 24 hours, and if the polymerization temperature is less than 50°C, polymerization occurs incompletely, and if it exceeds 90°C, the durability of the porous carbon material is deteriorated. In addition, if the polymerization time is less than 10 minutes, polymerization incompletely occurs, and if the polymerization time exceeds 24 hours, a large amount of a diazonium salt homopolymer is produced, thereby deteriorating the adsorption properties.

In the present invention, prior to step (a), the surface of the porous carbon material may be photooxidized.

The photooxidation may be performed without limitation as long as it is a method capable of introducing a functional group in the form of an oxide onto the surface of the porous carbon material. It is preferable to irradiate ultraviolet rays, and the irradiation amount and irradiation time can be adjusted depending on the degree of photooxidation.

At this time, functional groups that can be introduced to the surface of the porous carbon material by photooxidation include a hydroxyl group, a carboxyl group, an ester group, and an ether group.

Since the functional group introduced by the photooxidation has excellent bonding strength with the diazonium salt, coating properties and bonding strength of the diazonium salt formed on the surface of the porous carbon material can be improved.

The photooxidation is preferably irradiated with ultraviolet rays for 2 to 30 minutes, more preferably, ultraviolet rays are irradiated for 5 to 20 minutes. When the photooxidation time is less than 2 minutes, the functional groups cannot be effectively introduced, and when the photooxidation time exceeds 30 minutes, the surface properties of the porous carbon material may be deteriorated.

In addition, the present invention can perform additional surface modification by treating the modified porous carbon material with a copolymer of an acrylate group-containing silane coupling agent and an acrylic acid monomer.

The copolymer may be covalently bonded to the surface of the porous carbon material or may be bonded to the graft polymer introduced by a diazonium salt, through which a plurality of carboxyl groups may be introduced into the surface of the porous carbon material.

A plurality of carboxyl groups included in the copolymer may be combined with metals, fine dust, or various compounds, and adsorption characteristics, harmful gas removal characteristics, antibacterial properties, and the like may be improved.

When a copolymer having excellent thermal stability is covalently bonded to the surface of a porous carbon material, the copolymer is thermally stable and not decomposed even under high temperature conditions such as coating process and filter manufacturing process, so adsorption properties, harmful gas removal properties, Antimicrobial properties and the like can be expressed for a long time.

As the acrylate group-containing silane coupling agent, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltri Ethoxysilane, 3-acryloxypropyltrimethoxysilane, methacryloxymethyltriethoxysilane, and methacryloxymethyltrimethoxysilane.

The acrylic acid monomer is acrylic acid, methacrylic acid, methyl acrylic acid, ethyl acrylic acid, butyl acrylic acid, 2-ethyl hexyl acrylic acid, decyl acrylic acid, methyl methacrylic acid, ethyl methacrylic acid, butyl methacrylic acid, 2-ethyl hexyl methacrylic acid , Decyl methacrylic acid, and the like.

The weight ratio of the acrylate group-containing silane coupling agent and the acrylic acid monomer is preferably 10 to 30:70 to 90, and if the weight ratio is less than 10:90, the bonding strength with the porous carbon material decreases, and if it exceeds 30:70, adsorption The characteristics are deteriorated.

The copolymer of the acrylate group-containing silane coupling agent and the acrylic acid monomer is preferably 1 to 10 parts by weight based on 100 parts by weight of the porous carbon material, and when the content of the copolymer is less than 1 part by weight, the introduction of functional groups is insignificant, and thus the adsorption characteristics are poor. If it is lowered and exceeds 10 parts by weight, the porosity of the prepared porous carbon material is rather small, and thus harmful gases and fine dust cannot be effectively adsorbed.

In addition, the present invention can perform additional surface modification by treating the modified porous carbon material with a metal solution.

The functional group formed on the surface of the porous carbon material and the metal of the metal solution may form a metal complex.

That is, the functional group of the polymer graft-polymerized on the surface of the porous carbon material and the carboxyl group of the copolymer can form a metal complex with the metal of the metal solution.

Functional groups such as carboxyl group, hydroxyl group, sulfonic acid group, and phosphoric acid group can form a stable complex with a metal, and the metal is not easily desorbed even under high temperature conditions.

Gold, silver, copper, cobalt, nickel, zinc, platinum, and the like may be used as the metal without limitation.

The metal formed on the surface of the porous carbon material can be combined with harmful gases, fine dust, viruses, etc., so that adsorption properties, harmful gas removal properties, and antibacterial properties can be improved.

A metal precursor may be used to form the metal complex, and silver nitrate, silver sulfate, silver acetylacetonate, silver acetate, silver carbonate, silver chloride, copper nitrate, copper sulfate, copper acetylacetonate, copper acetate, copper carbonate, copper Chloride and the like can be used.

The content of metal is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the porous carbon material.If the metal content is less than 0.1 parts by weight, the effect of the addition is insignificant, and if it exceeds 5 parts by weight, the surface of the porous carbon material The complex cannot be distributed evenly.

The step (b) is a step of drying the modified porous carbon material, and a solvent, an unreacted compound, and the like may be removed.

The modified porous carbon material may be dried for 5 to 100 minutes at 30 to 100°C using a device such as a vacuum oven or a hot air oven.

The step (c) is a step of irradiating the dried porous carbon material with ultraviolet rays, and the surface of the porous carbon material may be photooxidized.

The photooxidation may be performed without limitation as long as it is a method capable of functionalizing the graft polymer formed on the surface of the porous carbon material into an oxide form. It is preferable to irradiate ultraviolet rays, and the irradiation amount and irradiation time can be adjusted depending on the degree of photooxidation.

At this time, the graft polymer formed on the surface of the porous carbon material may include functional groups such as a hydroxyl group, a carboxyl group, an ester group, and an ether group through intra-chain reaction and inter-chain reaction by photooxidation.

Since the functional group introduced by photooxidation has excellent bonding power with metals, fine dust, and organic compounds, it is possible to improve adsorption characteristics and harmful gas removal characteristics. In addition, by the photooxidation, a microstructure is formed on the surface of the porous carbon material, and surface roughness, surface area, and porosity are increased, thereby improving adsorption characteristics and harmful gas removal characteristics.

The photooxidation is preferably irradiated with ultraviolet rays for 2 to 30 minutes, more preferably, ultraviolet rays are irradiated for 5 to 20 minutes. When the photooxidation time is less than 2 minutes, the functional groups cannot be effectively introduced, and when the photooxidation time exceeds 30 minutes, the surface properties of the porous carbon material may be deteriorated.

In addition, the present invention relates to a porous carbon material having excellent adsorption properties prepared by the above manufacturing method.

In the porous carbon material, a diazonium salt having at least one functional group selected from a carboxyl group, a hydroxyl group, a sulfonic acid group and a phosphoric acid group is graft-polymerized on the surface, and the graft polymer is a hydroxyl group, a carboxyl group, an ester group, and an ether by photooxidation. It may further include functional groups such as group.

In addition, by the photooxidation, a microstructure is formed on the surface of the porous carbon material, and surface roughness, surface area, and porosity are increased, thereby improving adsorption characteristics and harmful gas removal characteristics.

The pores present in the porous carbon material have a diameter of 1 to 100 nm, preferably 2 to 50 nm.

The porous carbon material has excellent properties for removing harmful gases, removing fine dust, and adsorption properties, and thus can be stably used for a long period of time in fields such as catalysts, supports, adsorbents, filters, masks, separators, and sensors.

The present invention will be described in detail through examples and comparative examples below. The following examples are only illustrated for the practice of the present invention, and the contents of the present invention are not limited by the following examples.

(Example 1)

Into a 2L reaction vessel installed in an ice bath, 1L of 0.2M HCl was added and stirred at 300rpm.

After adding 27.428 g of 4-aminobenzoic acid, 250 mL of 0.02M NaNO ₂ was added using a peristaltic pump at a rate of 20 mL/min.

The mixture was stirred at 300 rpm for 2 hours to obtain a diazonium salt having a carboxyl group.

A constant temperature water bath maintained at 70°C was prepared on a hot plate, and after immersing a 500 mL flask in the constant temperature water bath, 100 mL of the diazonium salt having a carboxyl group obtained above was added to the flask.

After impregnation by adding spherical porous carbon balls to the flask, 0.03 mol of potassium sulfate was added to 1 mol of diazonium salt having a carboxyl group, followed by stirring at 500 rpm for 1 hour to perform graft polymerization. At this time, the content of the diazonium salt was 5 parts by weight based on 100 parts by weight of carbon balls.

After that, the carbon ball was taken out, washed with distilled water, and dried at 70° C. for 30 minutes using a vacuum oven.

The surface of the dried carbon ball was irradiated with ultraviolet light (wavelength: 184.9 and 253.7, intensity: 28 mW/cm ² ) for 10 minutes to perform photooxidation treatment to prepare a porous carbon ball having excellent adsorption properties. At this time, UV irradiation was performed at room temperature and pressure using a UV-ozone cleaner (UVO cleaner AH-1700, AHTECH LTS Co. Ltd.).

1 is a scanning electron microscope (SEM) image of a surface-modified porous carbon ball according to Example 1 (FIG. 1(a)), a microstructure is formed on the surface of the porous carbon ball, and surface roughness, surface area, and porosity are increased. It can be seen that.

On the other hand, it can be seen that the surface of the porous carbon ball without surface modification is relatively smooth and the surface area and porosity are low (FIG. 1(b)).

2 shows the adsorption characteristics of porous carbon balls to butane gas according to the concentration of diazonium salt.

It can be seen that the adsorption time and adsorption amount of butane gas increase as the concentration of the diazonium salt increases.

(Example 2)

A porous carbon ball was prepared in the same manner as in Example 1, except that 0.5 parts by weight of a diazonium salt was used based on 100 parts by weight of the carbon balls.

(Example 3)

A porous carbon ball was prepared in the same manner as in Example 1, except that 12 parts by weight of a diazonium salt was used based on 100 parts by weight of the carbon balls.

(Example 4)

A porous carbon ball was manufactured in the same manner as in Example 1, except that the surface of the dried carbon ball was irradiated with ultraviolet rays for 1 minute.

(Example 5)

A porous carbon ball was prepared in the same manner as in Example 1, except that the surface of the dried carbon ball was irradiated with ultraviolet rays for 40 minutes.

(Example 6)

A copolymer was prepared by copolymerizing 20% by weight of 3-methacryloxypropyltrimethoxysilane and 80% by weight of methacrylic acid.

Porous carbon balls were prepared in the same manner as in Example 1, except that the porous carbon balls were surface-treated with diazonium having a carboxyl group and then treated with the copolymer. At this time, 5 parts by weight of a copolymer relative to 100 parts by weight of carbon balls was used.

(Comparative Example 1)

A porous carbon ball was prepared in the same manner as in Example 1, except that the diazonium salt was not treated.

(Comparative Example 2)

A porous carbon ball was manufactured in the same manner as in Example 1, except that ultraviolet light was not irradiated.

The porosity and adsorption properties of the porous carbon balls prepared from the Examples and Comparative Examples were measured, and the results are shown in Table 1 below.

The porosity of the porous carbon ball was measured based on BET analysis.

The adsorption characteristics of the porous carbon balls are determined by gas chromatography, in which the porous carbon balls are inserted into the test tube, and in this state, butane gas is injected into the test tube to change the concentration of butane gas passing through the porous carbon balls over time. Was measured.

division Example Comparative example One 2 3 4 5 6 One 2 Pore volume
(cc/g) 0.672 0.629 0.638 0.645 0.631 0.745 0.448 0.491 Adsorption time
(minute) 1,080 980 945 965 975 1,250 415 510

From the results of Table 1, it can be seen that the porous carbon balls of Examples 1 to 6 have excellent porosity and adsorption properties. In particular, Examples 1 and 6 have the most excellent properties.

On the other hand, it can be seen that the above properties of the porous carbon balls of Comparative Examples 1 and 2 are inferior to those of the Examples.

Claims (5)

(a) treating the porous carbon material with a diazonium salt having at least one functional group selected from carboxyl group, hydroxyl group, sulfonic acid group and phosphoric acid group to modify the surface of the porous carbon material;
(b) treating the modified porous carbon material with a copolymer of an acrylate group-containing silane coupling agent and an acrylic acid monomer;
(c) drying the porous carbon material treated with the copolymer; And
In the method for producing a porous carbon material having excellent adsorption properties, comprising the step of (d) irradiating the dried porous carbon material with ultraviolet rays,
Step (a)
1 to 10 parts by weight of diazonium salt is used per 100 parts by weight of the porous carbon material,
Step (b)
1 to 10 parts by weight of the copolymer is used based on 100 parts by weight of the porous carbon material,
The weight ratio of the acrylate group-containing silane coupling agent and the acrylic acid monomer is 10 to 30:70 to 90,
Step (c)
Dry the porous carbon material treated with the copolymer at 30-100℃ for 5-100 minutes,
Step (d)
A method for producing a porous carbon material having excellent adsorption properties, characterized in that the dried porous carbon material is irradiated with ultraviolet rays for 2 to 30 minutes.
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