KR100913998B1 - Macro-porous honeycomb carbon structure and the method for preparing it - Google Patents

Abstract

Macro-porous honeycomb carbon structure and a method for manufacturing the same are provided to produce carbon structure having adjustable and uniform macro-pores, and to offer simple function and reproducibility. A manufacturing method of macro-porous honeycomb carbon structure includes the following steps of: injecting a nano silica particle of 200~700nm size in which a metallic catalyst is dipped in a polymer resin having a diameter of 0.5~15 mm and apparent density of 0.1~0.5 g/cc; gaining carbon structure having a void of 200~700 nm size in which the silica particle is removed; and exposing the void by exploding the surface of the carbon structure. The diameter of the polymer resin is 1~4 mm. The metallic catalyst is selected from a group consisting of aluminum, Cu, Fe, Ni, Co, Mn, Mo, Pd, Ag, Au, Ru, and Rh.

Description

Atmospheric honeycomb carbon structure and its manufacturing method {Macro-porous honeycomb carbon structure and the method for preparing it}

The present invention relates to a porous carbon structure, and more particularly to a carbon structure having a uniform macropore of 100 nm or more while having a size on the order of hundreds of micrometers to millimeters.

Porous materials are usually divided into micropores of 2 nm or more, mesopores of 2-50 nm, and macropores of 50 nm or more, depending on the diameter size of the pores. Porous materials include various inorganic materials, metals, polymers, etc. Among them, porous carbon structures are used in various fields due to their excellent chemical, physical, and mechanical properties.

As an important technique for producing porous carbon structures, carbon precursors are injected using a medium porous silica molecular sieve (MCM-48 material) as a template, followed by carbonization of carbon precursors under non-oxidizing conditions, followed by silica template with HF or NaOH solution. A method of producing a porous carbon structure by dissolving and removing it has been proposed. In addition, Korean Patent Registration Nos. 10-0481736, 10-0551602, 10-0438210, and 10-0574030, etc., propose various techniques for preparing nano-sized carbon capsules. Various methods have been proposed for producing a carbon structure having a homogeneous porous structure interconnected, and continuous improvements have been made, but it is still not easy to produce a carbon structure having an interconnected uniform porous structure. And most of the carbon structures thus obtained are in the order of nanometers to a few micrometers, and dust and other problems may be more severe than conventional granular activated carbon unless the nanoscale size is required in terms of performance and functionality. have. In particular, when the carbon structure is applied to a filter for removing odors and volatile organic compounds, the micro level or more is more useful. Most powdered adsorbents are often manufactured in pellet form to size in millimeters. Therefore, if the size of the carbon structure can be approximated to the millimeter level, it is very advantageous to use as an adsorbent.

Korean Patent Publication No. 1982-0000986, Patent No. 10-0450642, Patent No. 10-0438210, and the like, methods for producing spherical carbon structures having a micro level or more using pitches or polymer resins, which are carbon precursors, are described. Suggesting. However, the carbon structures manufactured by this method have porosity, but even though the pores are small in size, they are only in the form of dense carbon masses.

Various techniques have been proposed for the fabrication of carbon structures, but it is still easy to produce carbon structures with uniform, scalable macropores of 100 nm or more with dimensions on the order of hundreds of micrometers to millimeters. I didn't do it. In addition, it is not known yet how to easily prepare such a carbon structure using a solid polymer resin and a solid nanosilica.

 It is an object of the present invention to provide a honeycomb carbon structure as a network combination having macropores of 100 nm or more at a level of several hundred micrometers to millimeters in diameter and in which these pores are connected to each other and exposed to the surface, and a method of manufacturing the same.

In addition, an object of the present invention is to provide a simple and reproducible method for producing a carbon structure having a uniform pore size and macropores of 100 nm or more while having a size on the order of several hundred micrometers. In particular, it is an object of the present invention to provide a simple and reproducible method for producing a carbon structure having macropores using solid polymer resin particles and solid nanosilica particles.

Other objects and advantages of the present invention will be described below and will be better understood by practice of the present invention.

In the present invention to achieve the above object,

200-700 ㎚ in which the silica particles were removed by injecting carbonized nanoetched particles of 200-700 nm in the bulk polymer resin particles having an apparent density of 0.1-0.5 g / cc and a diameter of 0.5-15 mm. After obtaining a carbon structure having air holes of a size, the surface of the carbon structure is ruptured to provide a honeycomb carbon structure in which the air holes are exposed to the outside.

In the present invention,

(a) injecting 200-700 nm nanosilica particles into the bulk polymeric resin particles having an apparent density of 0.1-0.5 g / cc and a diameter of 0.5-15 mm;

(b) carbonizing the polymer-silica composite beads into which the nanosilica particles are injected, and then etching the silica portion to obtain a carbon structure having an air hole having a size of 200 to 700 nm; And

(C) there is provided a method for producing a honeycomb carbon structure comprising rupturing the surface of the carbon structure having the air hole to expose the air hole to the outside.

In the present invention, a carbon structure on the order of millimeters at several hundred micrometers in diameter having a macropore with a uniform and adjustable size of 100 nm or more is produced by a simple and reproducible method. In particular, the manufacturing method of the present invention, unlike the conventional manufacturing method that reacted to the surface of the inorganic material in the liquid phase or gas phase using a polymer monomer, a crosslinking agent and a catalyst, using a solid polymer resin particles and a solid nanosilica particles directly Produces atmospheric air carbon structure with uniform pore size control. The production method of the present invention can be directly applied to the mass production process is simple and efficient process and high production yield.

Carbon structure according to the present invention is not a simple capsule type honeycomb structure, the air hole is exposed to the outside and the inner air hole has a network structure connected by pores of about 100 nm on average. Therefore, the carbon structure of the present invention is very useful for adsorption of inorganic particles, high molecular materials, viruses, bacteria, bacteria, etc. of 20-100 nm in size, and is also useful as a support for carrying catalysts of nanoparticle size. Previously reported nano-sized encapsulated carbon structures have many pores of a size that are not involved in adsorption, and thus were ineffective as adsorbents or supports. However, the carbon structure of the present invention is a honeycomb structure of air holes, which are not found in the existing activated carbon structure, and the air holes are exposed to the outside while the air holes of 200 to 700 nm are formed uniformly. Since the structure is developed in a honeycomb form by interconnecting the pores of about 1/5 the size of the pore size, it can be an effective optimal structure consisting of pores of the appropriate size or more to be involved in the adsorption.

In the present invention, a polymer resin particle that can serve as a carbon precursor while providing a bulk space of 200 nm or more is used as a starting material. The polymer resin particles are preferably bulk polymer resin beads having an apparent density of about 0.1 to 0.5 g / cc and a diameter of about 0.5 to 15 mm, more preferably 1 to 4 mm in diameter. The polymer resin beads are not limited in kind to the polymer. Polymer resin beads can be produced by a known method known in the art. For example, bulk polymer resin beads may be manufactured by a method known in Korea Patent Publication No. 1982-0000986, Registration No. 10-0450642, Registration No. 10-0438210, and the like. As a specific example, a polymer resin bead may be obtained by dissolving an organic monomer, an aldehyde and a surfactant, including a hydroxyl group or an amine group capable of sol-gel polymerization in water, and then polymerizing at a predetermined temperature. At this time, since the polymerization reaction of the monomer and the aldehyde proceeds in the spherical organic layer formed by the surfactant, it is possible to obtain the spherical bulk polymer resin beads. Alternatively, spherical bulk polymer resin beads may be obtained by reacting formaldehyde with an organic monomer containing a hydroxyl group or an amine group under similar conditions. The polymer resin beads thus prepared may be prepared in a desired size using a sieve network.

Nanosilica particles can be prepared by known sol-gel methods (Journal of Colloid and Interface Science 227, 301-315 (2000)). The nanosilica particles used in the present invention are preferably 200 to 700 nm. Preferably, the metal silica is supported on the nanosilica particles. As the metal catalyst, Cu, Fe, Ni, Co, Mn, Mo, which are aluminum or transition metals, or Pd, Ag, Au, Ru, Rh, which is a noble metal, can be used. The reason for using the nano-silica particles loaded with a metal catalyst is to finally make a structure in which the air holes of the carbon structure are connected to each other, and may induce bonding between the nano-silica particles in the firing step. In addition, the supported metal catalyst may provide an acid point to prevent the carbon body from being in close contact with the silica surface during the carbonization, thereby increasing the etching efficiency in the subsequent etching step.

In the present invention, the nano-silica particles are injected into the bulk polymer resin beads so that the nano-silica particles can enter the inside of the bulk polymer resin beads. As a method of injecting, preferably, the polymer resin beads and the nanosilica particles are supported together in an aqueous solution, and then the temperature is raised under reduced pressure to evaporate and dry the aqueous solution. According to a preferred embodiment of the present invention, 100 parts by weight of polymer resin beads and 1 to 100 parts by weight of nanosilica particles are supported on 200 to 300 parts by weight of an aqueous solution, and the temperature is raised to 80 to 90 ° C. while reducing the pressure using a vacuum pump. The solution is evaporated to dryness.

Carbon structures are prepared by carbonizing the polymer-silica composite beads on which nanosilica particles are supported. In this case, preferably, two steps of heat treatment are performed. First, the composite beads are heat treated at about 300 to 400 ° C. to shrink the polymer resin, thereby inducing the resin portion of the polymer beads to be in close contact with the surface of the nanosilica. Conditions may vary slightly depending on the type of carbon precursor, but most polymer resins shrink under thermal decomposition under the same conditions. When directly carbonized at a high temperature without going through such a step, the polymer is not uniformly adhered to the surface of the injected nanosilica, and thus air holes are difficult to be uniformly and uniformly formed in the finally obtained carbon structure. In addition, since the overall size of the polymer resin shrinks in the first step, the size of the polymer resin, which is a starting material, is preferably 30-40% larger than the size of the carbon structure to be finally obtained. Thereafter, in the second step, the carbon structure is finally heat-treated to allow carbonization of the polymer resin at about 800 to 1000 ° C. in an inert gas atmosphere to finally prepare a carbon structure surrounding the nano silica particles. In this step, the thermal decomposition of the polymer resin may be accelerated to increase carbonization, and the carbon component may be prepared in a composition of 90% or more relative to the carbon weight ratio.

The silica-carbon composite obtained through the carbonization process is treated with hydrofluoric acid solution or aqueous sodium hydroxide solution to etch away the silica portion to obtain a carbon structure having an air hole having a size of 200 to 700 nm. Finally, the surface of the carbon structure having the air holes, that is, the outer shell is broken to obtain the honeycomb carbon structure of the present invention in which the air holes are exposed to the outside. The partial rupture of carbon on the surface of the carbon structure can be preferably performed using an oxidizing agent such as hydrogen peroxide.

Hereinafter, a method of manufacturing the honeycomb carbon structure of the present invention will be described in detail for each step.

Injecting nanosilica particles into bulk polymer resin beads

The bulk polymer resin beads and nanosilica particles having an apparent density of 0.1 to 0.5 g / cc and a diameter of 0.5 to 15 mm are supported together in an aqueous solution, and then the temperature is increased under reduced pressure to evaporate and the aqueous solution is evaporated to dry. Inject the particles. Preferably, 100 parts by weight of the polymer resin beads and 1 to 100 parts by weight of the nano-silica particles are immersed in 200 to 300 parts by weight of the aqueous solution, and the temperature is raised to 80-90 ° C. under reduced pressure using a vacuum pump to evaporate and dry the aqueous solution. Let's do it. In this case, as the aqueous solution, alcohols or distilled water may be used.

The nano silica particles are preferably nano silica particles on which a metal catalyst is supported. As a method of supporting the metal catalyst on the nanosilica particles, preferably, the nanosilica and the metal catalyst are supported together in an aqueous solution, and then the aqueous solution is evaporated and then calcined again in a calcination furnace. At this time, alcohol, secondary distilled water, or the like can be used as the aqueous solution. More preferably, 100 parts by weight of the nanosilica and 1 to 5 parts by weight of the metal catalyst are supported together in 100 to 200 parts by weight of an aqueous solution and left at room temperature for 10 to 48 hours, and then at 100 ° C. or higher, preferably at about 100 to 120 ° C. After evaporating the aqueous solution, the resultant is calcined for about 3 to 7 hours at about 450 to 650 ° C. in the kiln to obtain nanosilica particles loaded with a metal catalyst.

Carbonization and Silica Etching Steps of Polymer-Silica Composite Beads

After carbonizing the polymer-silica composite beads in which the nanosilica particles obtained in the above step are carbonized, the silica portion is etched to obtain a carbon structure having an air hole having a size of 200 to 700 nm.

In this case, carbonization is preferably performed through the following two steps to form air holes uniformly and uniformly in the finally obtained carbon structure. In the first stage, the temperature is raised to 1 ~ 3 ℃ / min in the air atmosphere and maintained at 300 ~ 400 ℃ for 1 ~ 3 hours. In this process, the polymer resin part of the composite bead is contracted to be in close contact with the surface of the nanosilica. Thereafter, in the second step, the carbonization of the polymer resin proceeds by increasing the temperature to 800-1000 ° C. at a temperature rising rate of 1-10 ° C./min in an inert gas atmosphere for 5-10 hours. Argon, helium, nitrogen and the like may be used as the inert gas. In this manner, the nano-silica particles and the carbon structure surrounding the outer shell, that is, silica-carbon composite are manufactured.

The silica portion is etched from the silica-carbon composite thus obtained to obtain a carbon structure having air holes of 200 to 700 nm in size. Etching may be performed by known conventional methods used in the manufacture of porous carbon structures. Preferably, the prepared silica-carbon composite is treated with aqueous hydrofluoric acid solution or aqueous sodium hydroxide solution. More preferably, 10 to 30 parts by weight of the silica-carbon composite is loaded on 100 parts by weight of 20 to 50% hydrofluoric acid solution or 30 to 50% sodium hydroxide aqueous solution and reacted at 30 to 80 ° C. for 10 to 24 hours. After the reaction is completed, the solids are separated using a filter membrane or the like and completely dried at 100 ° C.

Sheath rupture stage of carbon structure

The surface of the carbon structure having the air pores obtained in the step is ruptured to expose the air pores to the outside. An oxidizing agent is preferably used for the surface of the carbon structure, that is, the breakage of the carbon shell. Oxidizing agents include ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ), hydrogen peroxide (H ₂ O ₂ ), nitric acid, sulfuric acid, hypochloric acid (HClO) and salts thereof, permanganic acid (HMnO ₄ ), and chromic acid (H ₂ CrO ₄ ) and salts thereof may be used, in particular 30 to 50% hydrogen peroxide water. More preferably, 10 parts by weight of the carbon structure is supported on 100 parts by weight of 30-50% hydrogen peroxide solution and left at 30 to 80 ° C. for 10 to 24 hours to rupture the carbon portion of the surface of the carbon structure. Then, filtered and dried using a filter membrane.

In the air hole honeycomb carbon structure according to the present invention, the air holes are exposed to the outside while the air holes of 200-700 nm, which are nano-silica particle sizes injected into the polymer resin, are uniformly formed. It is a carbon structure developed in honeycomb form by interconnecting with pores of about 5 size. The honeycomb carbon structure of the present invention may be usefully used as a support for adsorbing inorganic particles or polymer compounds of 20 to 100 nm or bacteria, bacteria, viruses, or the like, or supporting catalysts in units of tens of nm.

EXAMPLE

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the scope of the present invention is not limited by the following examples, and those skilled in the art to which the present invention pertains should be within the equivalent scope of the technical concept of the present invention and the claims to be described below. Of course, various modifications and variations are possible.

Example 1

(1) 100 parts by weight of nanosilica particles having an average diameter of about 300 nm and AlNO _{3 ·} 6H ₂ O 3 parts by weight were simultaneously supported in 150 parts by weight of 70% ethanol, stirred at room temperature for 24 hours, and then heated to 100 ° C. Water was evaporated to dryness to obtain nanosilica particles loaded with a metal catalyst in the form of a solid powder.

(2) 100 parts by weight of polymer resin beads having a diameter of 1 to 2 mm and 50 parts by weight of the nano-silica particles on which the metal catalyst was obtained were simultaneously loaded in 200 parts by weight of secondary distilled water and stirred at room temperature for 1 hour, followed by a vacuum pump. The temperature was raised to 80 ° C. under reduced pressure and maintained until the water was completely evaporated to inject nanosilica particles into the polymer resin beads.

(3) While blowing the polymer beads into which the nanosilica particles are injected can be controlled at a temperature and heated to 1000 ° C. while blowing air at 50 ml / min, the temperature increase rate is 1 ° C./min to 300 ° C. After raising for 1 hour, while maintaining the inert atmosphere by blowing nitrogen gas again, the temperature was raised to 3 ° C./min and maintained at 900 ° C. for 5 hours, followed by cooling to form a carbon structure and a nanosilica composite.

(4) 10 parts by weight of the carbon structure and the nanosilica composite prepared above were loaded on 100 parts by weight of 25% hydrofluoric acid aqueous solution, and left at room temperature for 24 hours to etch the silica portion, followed by filtration and drying.

(5) 10 parts by weight of the carbon structure obtained in (4) was immersed in 100 parts by weight of 30% hydrogen peroxide solution and left at room temperature for 24 hours to rupture the carbon on the surface of the carbon structure, followed by filtration and drying to form a honeycomb carbon structure having atmospheric pores. Got.

A scanning electron microscope (SEM) image of the honeycomb carbon structure thus prepared is shown in FIG. 1. From the SEM image, it can be seen that the air pores having an average pore diameter of about 300 nm are carbon structures that have been developed in a honeycomb form.

Comparative Example 1

In Example 1 (5) except that the process of rupturing the carbon on the surface of the carbon structure was carried out in the same manner as in Example 1 to prepare a carbon structure. An SEM image of the prepared carbon structure is shown in FIG. 2. From the SEM image, it can be seen that the carbon structure has pores having an average pore diameter of about 300 nm, but the pores are not exposed to the surface.

The honeycomb carbon structure of the present invention may be usefully used as a support for adsorbing inorganic particles or polymer compounds of 20 to 100 nm or bacteria, bacteria, viruses, or the like, or for supporting catalysts of several tens of nm. In particular, the honeycomb carbon structure of the present invention can be used for vehicle filters, air purifier filters, etc., and preventive products such as sick house syndrome, new car syndrome, new furniture syndrome, refrigerator deodorant, foot odor, sweat odor remover, mold odor remover, etc. It can be widely used in various fields including material deodorization, environmentally friendly interior materials, clothes, duvet, bed, shoe lining and so on.

1 is a scanning electron microscope (SEM) image of a honeycomb carbon structure of the present invention prepared according to Example 1. FIG.

FIG. 2 is a scanning electron microscope (SEM) image of a carbon structure prepared according to Comparative Example 1. FIG.

Claims (10)

Inside the bulk polymer resin particles having an apparent density of 0.1 to 0.5 g / cc and a diameter of 0.5 to 15 mm, nano-silica particles of 200 to 700 nm size with a metal catalyst were injected therein, followed by carbonization and etching. After obtaining a carbon structure having the air hole of 200 ~ 700 nm size is removed, the surface of the carbon structure is ruptured honeycomb carbon structure exposing the air hole to the outside. The honeycomb carbon structure according to claim 1, wherein the polymer resin particles have a diameter of 1 to 4 mm. delete The method of claim 1, wherein the metal catalyst is aluminum; Cu; Fe; Ni; Co; Mn; Mo; Pd; Ag; Au; Ru; And Rh honeycomb carbon structure is selected from the group consisting of. (a) 100 parts by weight of bulk polymer resin particles having an apparent density of 0.1 to 0.5 g / cc and a diameter of 0.5 to 15 mm and 1 to 100 parts by weight of 200 to 700 nm nanosilica particles in 200 to 300 parts by weight of an aqueous solution. Thereafter, the temperature is raised to 80-90 ° C. under reduced pressure to evaporate and dry the aqueous solution to inject the nanosilica particles into the polymer resin particles. (b) carbonizing the polymer-silica composite beads into which the nanosilica particles are injected, and then etching the silica portion to obtain a carbon structure having an air hole having a size of 200 to 700 nm; And (C) a method of producing a honeycomb carbon structure comprising the step of rupturing the surface of the carbon structure having the air hole to expose the air hole to the outside. delete According to claim 5, The nano-silica particles are nano-silica particles loaded with a metal catalyst, prior to the step (a) by supporting 100 parts by weight of nano-silica and 1 to 5 parts by weight of the metal catalyst in 100 to 200 parts by weight of an aqueous solution 10 to 48 hours at room temperature and then heated to 100-120 ° C. to evaporate the aqueous solution and calcining it again at 450-650 ° C. for 3-7 hours to obtain nanosilica particles loaded with a metal catalyst. Method for producing honeycomb carbon structure. The method of claim 5, wherein the carbonization of step (b) comprises the steps of: (i) increasing the temperature at a temperature increase rate of 1 to 3 ℃ / min in the air atmosphere for 1 to 3 hours at 300 ~ 400 ℃; (Ii) A method for producing a honeycomb carbon structure comprising the step of raising to 800 ~ 1000 ℃ at a temperature rising rate of 1 ~ 10 ℃ / min in an inert gas atmosphere for 5 to 10 hours. The method of claim 5, wherein the rupturing of the surface of the carbon structure comprises ammonium persulfate; Hydrogen peroxide solution _; nitric acid; Sulfuric acid; Hypochloric acid and salts thereof; Permanganic acid (HMnO ₄ ); A method for producing a honeycomb carbon structure comprising reacting a carbon structure with an oxidant selected from the group consisting of chromic acid and salts thereof. The method of claim 5, wherein the rupturing of the surface of the carbon structure comprises 10 parts by weight of the carbon structure in 100 parts by weight of 30 to 50% hydrogen peroxide solution and left for 10 to 24 hours at 30 to 80 ℃ Method of making a structure.

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