WO2017039132A1 - Method for purification of carbon nanotubes - Google Patents

Method for purification of carbon nanotubes Download PDF

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WO2017039132A1
WO2017039132A1 PCT/KR2016/006740 KR2016006740W WO2017039132A1 WO 2017039132 A1 WO2017039132 A1 WO 2017039132A1 KR 2016006740 W KR2016006740 W KR 2016006740W WO 2017039132 A1 WO2017039132 A1 WO 2017039132A1
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carbon nanotubes
temperature
metal
chlorine
purification
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PCT/KR2016/006740
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French (fr)
Korean (ko)
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강경연
우지희
조동현
김욱영
이승용
장형식
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주식회사 엘지화학
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Priority to CN201680003101.1A priority Critical patent/CN106794991B/en
Publication of WO2017039132A1 publication Critical patent/WO2017039132A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/20—Vanadium, niobium or tantalum
    • B01J23/22—Vanadium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/24—Chromium, molybdenum or tungsten
    • B01J23/26—Chromium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/24—Chromium, molybdenum or tungsten
    • B01J23/28—Molybdenum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74—Iron group metals
    • B01J23/75—Cobalt
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity

Definitions

  • the present invention provides a purification method capable of providing carbon nanotubes of higher purity by removing impurities contained in carbon nanotubes prepared by reacting with a chlorine-containing compound.
  • carbon nanotubes are cylindrical carbon tubes having a diameter of about 3 to 150 nm, specifically about 3 to 100 nm, and having a length several times the diameter, for example, 100 times or more.
  • CNTs consist of layers of aligned carbon atoms and have different types of cores.
  • Such CNTs are also called, for example, carbon fibrils or hollow carbon fibers.
  • the CNT can be generally manufactured by an arc discharge method, a laser evaporation method, a chemical vapor deposition method, or the like.
  • the arc discharge method and the laser evaporation method is difficult to mass-produce, there is a problem that the economical efficiency is lowered due to excessive arc production cost or laser equipment purchase cost.
  • carbon nanostructures are typically produced by dispersing and reacting metal catalyst particles with a hydrocarbon-based feed gas in a high temperature fluidized bed reactor. That is, the metal catalyst is suspended in the fluidized bed reactor by the source gas and reacts with the source gas to grow carbon nanostructures.
  • Carbon nanotubes exhibit non-conductor, conductor or semiconducting properties according to their unique chirality, and the carbon atoms are connected by strong covalent bonds, so that their tensile strength is about 100 times greater than steel, and they have excellent flexibility and elasticity. It is also chemically stable, and because of its size and specific properties, it is industrially important in the manufacture of composites and has high utility in the field of electronic materials, energy materials and many other fields.
  • the carbon nanotubes may be applied to electrodes of an electrochemical storage device such as a secondary battery, a fuel cell or a super capacitor, an electromagnetic shield, a field emission display, or a gas sensor.
  • the catalyst metal used in the carbon nanotube fabrication process is treated as an impurity when attempting to use the carbon nanotube, and the above-mentioned metal impurities cause a problem that the basic physical properties such as thermal stability and chemical stability are reduced. Therefore, at this time, there is a need for a method of improving the basic physical properties of carbon nanotubes by purifying only carbon nanotubes.
  • the present invention provides a purification process for removing residual metal contained in carbon nanotubes without defects of the manufactured carbon nanotubes.
  • the present invention comprises the steps of chlorination of the residual metal by reacting the metal remaining in the carbon nanotubes with a chlorine-containing compound at a first temperature in a vacuum or inert atmosphere;
  • the second temperature T 2 may be performed at a temperature of T 1 + 100 ° C. or more.
  • the first temperature may be selected from 700 °C to 900 °C
  • the second temperature may be selected from 800 °C to 1300 °C.
  • the step of evaporating and removing the chlorinated metal at the second temperature may be performed by applying a vacuum, an inert gas atmosphere, or a vacuum atmosphere and an inert gas atmosphere alternately.
  • the pressure may be 500 tortor to 800 torr.
  • the reaction may be performed by supplying a chlorine-containing compound gas up to 500 tortor to 900 torr.
  • the total amount of metal impurities remaining in the purified carbon nanotubes may be 50 ppm or less.
  • the carbon nanotubes may be manufactured using a metal catalyst containing cobalt (Co), and at least one metal component of iron (Fe), molybdenum (Mo), vanadium (V) and chromium (Cr). It may be to include more.
  • the carbon nanotubes may have a Co content of 40 ppm or less after the purification process.
  • the carbon nanotubes may be prepared by chemical vapor deposition (CVD) on a fluidized bed reactor.
  • CVD chemical vapor deposition
  • the chlorine-containing compound may be chlorine (Cl 2 ) gas or trichloromethane (CHCl 3 ) gas.
  • the carbon nanotubes according to the present invention can remove residual metals generated in the manufacturing process of carbon nanotubes using a metal catalyst by reacting with a chlorine compound at a high temperature, thereby effectively removing impurities such as residual metals. Can be removed.
  • the chlorine gas treatment process that proceeds at a relatively low temperature of the first temperature and the metal chlorine removal process that proceeds to nitrogen (N 2 ) or the second temperature in a vacuum atmosphere can increase the metal removal efficiency remaining in the carbon nanotubes.
  • the second process is carried out in a nitrogen or vacuum atmosphere, the chlorine remaining in the carbon nanotubes can be removed together.
  • the physical properties of the carbon nanotubes can be further improved, and in particular, the thermal stability is improved and the oxidation decomposition temperature is markedly increased, and thus it can be usefully used for use as a flame retardant material and a metal complex.
  • 1A and 1B show SEM images before (Comparative Example 1) and after (Example 1) the CNT purification step.
  • FIG. 2A and 2B are graphs showing TEM_EDX results of carbon nanotubes according to Example 1 and Comparative Example 1.
  • FIG. 2A and 2B are graphs showing TEM_EDX results of carbon nanotubes according to Example 1 and Comparative Example 1.
  • Carbon nanotubes according to a preferred embodiment of the present invention
  • Chlorinating the residual metal by reacting the metal remaining in the carbon nanotubes with a chlorine-containing compound at a first temperature in a vacuum or inert atmosphere;
  • It provides a method for purifying carbon nanotubes comprising a.
  • the present invention uses a method of removing the residual metal generated from the metal catalyst used in the manufacturing process in the carbon nanotubes prepared, by reacting with a chlorine-containing compound at a high temperature to chlorinate the residual metal to evaporate.
  • a chlorine-containing compound at a high temperature to chlorinate the residual metal to evaporate.
  • the first temperature may be selected from 700 °C to 1000 °C
  • the second temperature may be selected from 800 °C to 1500 °C.
  • the metal impurity content remaining in the carbon nanotubes after the purification process may be reduced to 100 to 1000 times or more than before purification, that is, almost all of the metal remaining can be removed, which is the boiling point of the chlorinated metal
  • it may be to use the principle of evaporating all of the liquefied or gaseous metal to a higher temperature through the chlorination process, which is because the high temperature reaction of the gas phase is used, It has the advantage of not causing physical damage.
  • chlorination of the residual metal by reacting the metal remaining in the prepared carbon nanotubes with a chlorine-containing compound at a first temperature in a vacuum or inert gas atmosphere; And evaporating and removing the chlorinated residual metal at a second temperature higher than the first temperature.
  • the chlorine-containing compound may be chlorine (Cl 2 ) or trichloromethane (CHCl 3 ) gas. Since the chlorine-containing compound has low reactivity with the carbon nanotubes, damage to the carbon nanotubes manufactured may be further reduced.
  • a first temperature of the metal chlorination takes place (T 1) may be a 700 °C to 1000 °C, may be more preferably 700 °C to 900 °C. At temperatures below 700 ° C., chlorination of metal impurities such as catalyst metals in the carbon material may not be smooth.
  • the heating step after the chlorination of the metal is performed at a second temperature T 2 , which is higher than the first temperature T 1 , and specifically, T 2 may be a temperature of T 1 + 100 ° C. or higher. Preferably a temperature of T 1 + 100 ° C. or higher.
  • the second temperature may range from 800 ° C to 1500 ° C, preferably 900 ° C to 1400 ° C.
  • the removal reaction of chlorinated metal is not smooth and residual metal and chlorinated metal may remain in carbon nanotubes to act as impurities, which is carbon nanotubes. Can lower the physical properties.
  • catalyst graphitization by residual metal may occur at a temperature of 1500 ° C. or higher, and metal removal may not be easy.
  • the chlorination reaction carried out at the first temperature may be maintained for about 10 minutes to 1 hour to more fully chlorination of the residual metal, the total flow rate is adjusted according to the size of the carbon nanotubes and the reactor Can be.
  • the chlorination process may be performed by supplying the chlorine-containing compound gas to a pressure of 500 tortor to 900torr, preferably 600torr to 800torr, more preferably 600torr to 700torr.
  • the metal chlorination evaporation and removal reaction at the second temperature may be performed for 30 minutes to 300 minutes in an inert gas or vacuum atmosphere, and this may remove only the chlorinated residual metal without affecting carbon nanotubes.
  • the metal chlorine evaporation and removal reaction may proceed while alternately forming a vacuum atmosphere and an inert gas atmosphere, which may further increase the removal efficiency.
  • the chlorination of the residual metal may occur in a vacuum or fluorinated gas atmosphere. More specifically, the reaction in which the residual metal is chlorinated by adding a chlorine-containing compound gas after heating the carbon nanotube-filled reactor or reactor to a first temperature in a vacuum or nitrogen atmosphere. In this case, in the chlorination process performed at the first temperature, only the chlorination reaction of the metal may occur, and the removal reaction by evaporation of the chlorinated residual metal may occur mainly at the second temperature. At this time, the step of evaporation and removal of the residual metal is to stop the addition of the chlorine-containing compound and proceed again by converting the reaction furnace or the inside of the reactor into a vacuum atmosphere, the evaporation of the metal chloride may occur more smoothly.
  • the vacuum atmosphere means a pressure of 1 torr or less
  • the inert gas means an inert gas such as nitrogen (N 2 ) or argon (Ar).
  • the second step in which the evaporation and chlorinated metal removal reaction occurs may be performed by supplying a vacuum or inert gas to 500 tortor, preferably 600 to 700torr.
  • the metal chloride and chlorine compound removal and evaporation processes proceeding to the second temperature may be alternately applied with a vacuum and an inert gas atmosphere, and may be pressured in the form of a pulse. Specifically, after the vacuum is formed up to 1 torr, after a predetermined time, the inert gas is added again, the pressure is applied to 500 torr, and the process of forming the vacuum again may be repeated. Residual metals can be removed so that purification efficiency can be increased.
  • the total content of the metal impurities of the carbon nanotubes from which the residual metal is removed by the above method may be 50 ppm or less, and may be measured through the metal impurity ICP analysis of the carbon nanotubes.
  • the carbon nanotubes may be to use a metal catalyst containing a metal such as cobalt (Co), iron (Fe) as a main component, in this case, the content of the main component metal after purification is less than 40ppm each
  • the total content may be 50 ppm or less.
  • the content of the metal other than the main component may be measured to 1 ppm or less, for example, the content of iron (Fe), molybdenum (Mo), chromium (Cr), and vanadium (V). Each of these may be 5 ppm or less, preferably 1 ppm or less, respectively.
  • the carbon nanotube purification method as described above can effectively remove residual metals such as catalytic metals while using ultrasonic waves while suppressing damage or cutting of carbon nanotubes or solidifying carbon nanotubes to amorphous carbon materials. It can be purified without being able to suppress the physical damage or cutting of the carbon nanotubes, thereby providing a carbon nanotubes with improved mechanical and physical properties, in particular carbon nanotubes significantly improved in thermal stability Can be provided.
  • the carbon nanotubes according to the present invention may be prepared by growing carbon nanotubes by chemical vapor deposition (CVD) through decomposition of a carbon source using a supported catalyst, and the catalyst metal supported on the supported catalyst is carbon nanotubes. It will not be restrict
  • Examples of such a catalytic metal include at least one metal selected from the group consisting of Groups 3 to 12 of the Group 18 type periodic table recommended by IUPAC in 1990. Among them, at least one metal selected from the group consisting of Groups 3, 5, 6, 8, 9, and 10 is preferable, and iron (Fe), nickel (Ni), cobalt (Co), chromium (Cr), and molybdenum are preferred. At least one metal selected from (Mo), tungsten (W), vanadium (V), titanium (Ti), ruthenium (Ru), rhodium (Rh), palladium (Pd), platinum (Pt) and rare earth elements Particularly preferred.
  • a catalyst metal precursor inorganic salts, such as nitrate, sulfate, and carbonate of a catalyst metal
  • organic salts such as acetate, organic complexes, such as an acetylacetone complex, an organometallic compound, etc. It will not specifically limit, if it is a compound containing a catalyst metal.
  • the metal catalyst may further include one or more metals selected from cobalt (Co) and selected from iron (Fe), molybdenum (Mo), chromium (Cr), and vanadium (V).
  • the catalyst used in the carbon nanotube generation step is specifically a catalytically active metal precursor, Co (NO 3 ) 2 -6H 2O , (NH 4 ) 6 Mo 7 O 24 -4H 2 O, Fe (NO 3 ) 2 -6H 2 O or (Ni (NO 3) 2 -6H 2 O) was dissolved in distilled water, etc., and then, this Al 2 O 3, by wet impregnation (wet impregnation) of the support, such as SiO 2 or MgO may be manufactured.
  • a catalytically active metal precursor Co (NO 3 ) 2 -6H 2O , (NH 4 ) 6 Mo 7 O 24 -4H 2 O, Fe (NO 3 ) 2 -6H 2 O or (Ni (NO 3) 2 -6H 2 O) was dissolved in distilled water, etc., and then, this Al 2 O 3, by wet impregnation (wet impregnation) of the support, such as SiO 2 or MgO may be manufactured.
  • the catalyst may be prepared by ultrasonically treating a catalytically active metal precursor with a carrier such as Al (OH) 3 , Mg (NO 3 ) 2, or colloidal silica.
  • a carrier such as Al (OH) 3 , Mg (NO 3 ) 2, or colloidal silica.
  • the catalyst is prepared by the sol-gel method using a chelating agent such as citric acid (citric acid), tartaric acid (tartaric acid), so that the catalytically active metal precursor in water can be dissolved smoothly, or a catalyst that is well dissolved It may be prepared by co-precipitation of the active metal precursor.
  • a chelating agent such as citric acid (citric acid), tartaric acid (tartaric acid)
  • the supported catalyst and the carbon-containing compound can be prepared by contacting under a heating zone.
  • a supported catalyst by impregnation method in which the bulk density of the catalyst itself is higher than that of the coprecipitation catalyst and fine powder of 10 microns or less unlike the coprecipitation catalyst when the supported catalyst is used. This is because it is possible to reduce the possibility of fine powder due to wear (attrition) that can occur in the fluidization process, and because the mechanical strength of the catalyst itself is also excellent, it has the effect of stabilizing the operation of the reactor.
  • the aluminum-based support that can be used in the present invention may be one or more selected from the group consisting of Al 2 O 3 , AlO (OH) and Al (OH) 3 , and preferably may be alumina (Al 2 O 3 ).
  • the aluminum (Al) -based support may further include one or more selected from the group consisting of ZrO 2 , MgO and SiO 2 .
  • the aluminum (Al) -based support may have a spherical or potato shape, and may be made of a material having a porous structure, a molecular sieve structure, a honeycomb structure, or another suitable structure to have a relatively high surface area per unit mass or volume.
  • (4) calcining the resultant obtained by the vacuum drying to form a supported catalyst can be prepared by a method comprising a.
  • Carbon nanotubes can be prepared by chemical vapor phase synthesis in which carbon nanotubes are grown by chemical vapor phase synthesis through decomposition of a carbon source using the catalyst.
  • the chemical vapor phase synthesis method is a carbon nanotube catalyst is introduced into a fluidized bed reactor and at least one carbon source selected from saturated or unsaturated hydrocarbons having 1 to 4 carbon atoms at 500 °C ⁇ 900 °C, or the carbon source and hydrogen and nitrogen It can be carried out by injecting a mixed gas.
  • the carbon nanotubes are grown by injecting a carbon source into the catalyst for preparing carbon nanotubes, which may be performed for 30 minutes to 8 hours.
  • the carbon source may be a saturated or unsaturated hydrocarbon having 1 to 4 carbon atoms, such as ethylene (C 2 H 4 ), acetylene (C 2 H 2 ), methane (C 2 H 4 ), propane (C 3 H 8 ), and the like. May be, but is not limited thereto.
  • the mixed gas of hydrogen and nitrogen transports a carbon source, prevents carbon nanotubes from burning at a high temperature, and assists decomposition of the carbon source.
  • the carbon nanotubes prepared using the supported catalyst according to the present invention may be obtained in the form of a potato or sphere aggregate having a particle size distribution (D cnt ) of 0.5 to 1.0.
  • a catalyst obtained by impregnating and calcining a catalyst component and an active ingredient in a spherical or potato granular support also has a spherical or potato form without significant change in shape, and the carbon nanotube aggregates grown on such a catalyst also have a shape.
  • Another feature is to have a spherical or potato shape with only a large diameter without a large change of.
  • the spherical or potato shape refers to a three-dimensional shape such as a spherical and ellipsoidal shape having an aspect ratio of 1.2 or less.
  • the particle size distribution value (D cnt ) of the carbon nanotubes is defined by Equation 1 below.
  • Dn 90 is the number average particle diameter measured under 90% in absorbing mode using a Microtrac particle size analyzer after 3 hours of CNT in distilled water
  • Dn 10 is the number average particle diameter measured under 10%
  • Dn 50 is the number average particle diameter measured on a 50% basis.
  • the particle size distribution value may be preferably 0.55 to 0.95, more preferably 0.55 to 0.9.
  • the carbon nanotubes may be a bundle type or a non-bundle type having a flatness of 0.9 to 1, and the term 'bundle' used in the present invention, unless otherwise stated, refers to a plurality of carbon nanotubes. It refers to a bundle or rope form, in which the tubes are arranged or intertwined side by side.
  • 'Non-bundle (entangled) type' is a form without a certain shape, such as a bundle or rope shape, in the case of a bundle type CNT bundle may have a diameter of 1 to 50 ⁇ m.
  • Flatness ratio shortest diameter through the center of CNT / maximum diameter through the center of CNT.
  • the carbon nanotubes are characterized in that the bulk density (bulk density) is 80 ⁇ 250kg / m 3 .
  • the bulk density is defined by the following Equation 3, the density distribution of the carbon nanotubes can provide a range unique to the present invention.
  • the carbon nanotubes may have an average particle diameter of 100 to 800 ⁇ m, and a strand diameter of the carbon nanotubes may be 10 to 50 nm.
  • the boiling point can be lowered, and the temperature above the boiling point of the metal chloride
  • the carbon nanotubes may be purified using a process of evaporation and removal under conditions, and the carbon nanotubes manufactured by this method may have improved physical properties, and in particular, thermal stability may be improved, such as high temperature flame retardants and metal composite materials. It can be usefully used for carbon composites used in the environment.
  • Carbon nanotube synthesis was tested in a laboratory scale fixed bed reactor using a Co / Fe-containing metal catalyst for CNT synthesis. Specifically, the catalyst for synthesizing CNT prepared in the above process was mounted in the middle of a quartz tube having an internal diameter of 55 mm, and then heated up to 650 ° C. in a nitrogen atmosphere and maintained therein, while flowing hydrogen gas at a flow rate of 60 sccm. Synthesis was carried out for 2 hours to synthesize an entangled (non-bundle) type nanotube aggregate. The shape of the carbon nanotubes is shown in FIG. 1.
  • the shape of the purified first carbon nanotubes is shown in FIG. 1.
  • TEM_EDX was measured and observed in FIG. 2 for observing the change of the element before and after purification of the carbon nanotubes.
  • the carbon nanotubes of the examples and the comparative examples were analyzed by inductively coupled plasma spectrometry (ICP), and the contents of Fe, Co, Mo, V, and Cr in the carbon nanotubes were measured and shown in Table 1 below.
  • ICP inductively coupled plasma spectrometry
  • FIG. 2 The results of analyzing the surface elements of the carbon nanotubes before purification prepared in Comparative Example 1 and the purified carbon nanotubes prepared in Example 1 through the TEM-EDX analysis equipment are shown in FIG. 2. Comparing the peak before purification (Comparative Example 1) of FIG. 2A and the peak of FIG. 2B after purification (Example 1), it can be seen that peaks other than those shown in FIG. 2A do not appear in FIG. 2B. Cl 2 on the surface of the purified carbon nanotubes after the chlorine gas purification process according to the It can be proved that no gas remains.
  • the carbon nanotubes according to the present invention can remove residual metals generated in the manufacturing process of carbon nanotubes using a metal catalyst by reacting with a chlorine compound at a high temperature, thereby effectively removing impurities such as residual metals. Since it can be removed, the physical properties of the carbon nanotubes can be further improved, and in particular, the thermal stability is improved and the oxidation decomposition temperature is markedly increased, and thus it can be usefully used for use as a flame retardant material and a metal complex. .

Abstract

The present invention provides a method for purification of carbon nanotubes comprising a step of reacting metal remaining in carbon nanotubes with a chlorine-containing compound at a first temperature in a vacuum or inert atmosphere so as to chlorinate the residual metal, and evaporating and removing the chlorinated residual metal at a second temperature higher than the first temperature. The purification method according to the present invention can provide a purification method that does not cause physical damage or shape deformation of carbon nanotubes, by purifying the carbon nanotubes in a manner of evaporating a chlorinated metal.

Description

카본나노튜브의 정제방법Carbon Nanotube Purification Method
본 출원은 2015.07.24.자 한국 특허출원 제10-2015-0124773호에 기초한 우선권의 이익을 주장하며, 해당 한국 특허 출원의 문헌에 개시된 모든 내용은 본 명세서의 일부로서 포함된다.This application claims the benefit of priority based on Korean Patent Application No. 10-2015-0124773 filed on July 24, 2015, and all contents disclosed in the literature of the Korean patent application are incorporated as part of this specification.
본 발명은 염소 함유 화합물과 반응시켜 제조된 카본나노튜브에 포함된 불순물을 제거함으로써, 보다 고순도의 카본나노튜브를 제공할 수 있는 정제방법을 제공한다.The present invention provides a purification method capable of providing carbon nanotubes of higher purity by removing impurities contained in carbon nanotubes prepared by reacting with a chlorine-containing compound.
일반적으로 카본나노튜브(이하, 'CNT'라 한다)란 대략 3 내지 150㎚, 구체적으로는 약 3 내지 100㎚의 직경을 갖고, 길이가 직경의 수배, 예를 들어 100배 이상인 원통형 탄소 튜브를 지칭한다. 이러한 CNT는 정렬된 탄소 원자의 층으로 이루어지고, 상이한 형태의 코어를 갖는다. 또한 이러한 CNT는 예를 들면 탄소 피브릴 또는 중공 탄소 섬유라고도 불린다.Generally, carbon nanotubes (hereinafter referred to as 'CNT') are cylindrical carbon tubes having a diameter of about 3 to 150 nm, specifically about 3 to 100 nm, and having a length several times the diameter, for example, 100 times or more. Refer. These CNTs consist of layers of aligned carbon atoms and have different types of cores. Such CNTs are also called, for example, carbon fibrils or hollow carbon fibers.
상기 CNT는 일반적으로 아크 방전법, 레이저 증발법, 화학 기상 증착법 등에 의하여 제조할 수 있다. 이들 중, 아크 방전법 및 레이저 증발법은 대량 생산이 어렵고, 과다한 아크 생산 비용 또는 레이저 장비 구입 비용으로 인해 경제성이 저하된다는 문제가 있다.The CNT can be generally manufactured by an arc discharge method, a laser evaporation method, a chemical vapor deposition method, or the like. Among these, the arc discharge method and the laser evaporation method is difficult to mass-produce, there is a problem that the economical efficiency is lowered due to excessive arc production cost or laser equipment purchase cost.
화학 기상 증착법에서는 통상적으로 고온의 유동층 반응기 안에서 금속 촉매 입자와 탄화수소 계열의 원료 기체를 분산 및 반응시킴으로써 탄소 나노구조물이 생성된다. 즉, 금속 촉매는 원료 기체에 의해 유동층 반응기 안에서 부유하면서 원료 기체와 반응하여 탄소 나노구조물을 성장시킨다.In chemical vapor deposition, carbon nanostructures are typically produced by dispersing and reacting metal catalyst particles with a hydrocarbon-based feed gas in a high temperature fluidized bed reactor. That is, the metal catalyst is suspended in the fluidized bed reactor by the source gas and reacts with the source gas to grow carbon nanostructures.
카본나노튜브는 특유의 나선성(chirality)에 따라 부도체, 전도체 또는 반도체 성질을 나타내며, 탄소 원자들이 강력한 공유결합으로 연결되어 있어 인장강도가 강철 보다 대략 100 배 이상 크고, 유연성과 탄성 등이 뛰어나며, 화학적으로도 안정한 특성을 가지며, 이러한 크기 및 특정 물성으로 인해 복합재의 제조에서 산업적으로 중요하고, 전자 소재 분야, 에너지 소재 분야 및 기타 여러 분야에서 높은 활용성을 갖고 있다. 예를 들어, 상기 카본나노튜브는 이차 전지, 연료 전지 또는 슈퍼 커패시터(super capacitor)와 같은 전기 화학적 저장 장치의 전극, 전자파 차폐체, 전계 방출 디스플레이, 또는 기체 센서 등에 적용될 수 있다.Carbon nanotubes exhibit non-conductor, conductor or semiconducting properties according to their unique chirality, and the carbon atoms are connected by strong covalent bonds, so that their tensile strength is about 100 times greater than steel, and they have excellent flexibility and elasticity. It is also chemically stable, and because of its size and specific properties, it is industrially important in the manufacture of composites and has high utility in the field of electronic materials, energy materials and many other fields. For example, the carbon nanotubes may be applied to electrodes of an electrochemical storage device such as a secondary battery, a fuel cell or a super capacitor, an electromagnetic shield, a field emission display, or a gas sensor.
그렇지만, 카본나노튜브 제작과정에서 사용된 촉매 금속은 카본나노튜브를 이용하려고 할 때에는 불순물로서 취급되며, 상기한 금속 불순물에 의해 열적안정성 및 화학적 안정성과 같은 기초적 물성이 감소하는 문제가 발생된다. 따라서, 이때, 카본나노튜브만을 정제함으로써 카본나노튜브의 기초적 물성을 향상시키는 방법이 필요하다. However, the catalyst metal used in the carbon nanotube fabrication process is treated as an impurity when attempting to use the carbon nanotube, and the above-mentioned metal impurities cause a problem that the basic physical properties such as thermal stability and chemical stability are reduced. Therefore, at this time, there is a need for a method of improving the basic physical properties of carbon nanotubes by purifying only carbon nanotubes.
본 발명은, 제조된 카본나노튜브의 결함없이 카본나노튜브에 포함된 잔류금속을 제거하는 정제공정을 제공한다.The present invention provides a purification process for removing residual metal contained in carbon nanotubes without defects of the manufactured carbon nanotubes.
본 발명의 과제를 해결하기 위하여 본 발명은, 카본나노튜브에 잔류하는 금속을 진공 또는 불활성 분위기에서 제1온도로 염소 함유 화합물과 반응시켜 상기 잔류 금속을 염소화 하는 단계; 및In order to solve the problems of the present invention, the present invention comprises the steps of chlorination of the residual metal by reacting the metal remaining in the carbon nanotubes with a chlorine-containing compound at a first temperature in a vacuum or inert atmosphere; And
상기 제1온도 보다 높은 온도의 제2온도의 불활성 가스 또는 진공분위기에서 상기 염소화된 잔류 금속을 증발 및 제거하는 단계; Evaporating and removing the chlorinated residual metal in an inert gas or vacuum atmosphere at a second temperature higher than the first temperature;
를 포함하는 방법으로 정제한다. Purify by a method comprising a.
상기 제2온도(T2)가 T1+100℃ 이상의 온도에서 진행되는 것일 수 있다.The second temperature T 2 may be performed at a temperature of T 1 + 100 ° C. or more.
상기 제1온도가 700℃ 내지 900℃ 에서 선택되고, 상기 제2 온도가 800℃ 내지 1300℃ 에서 선택되는 것일 수 있다. The first temperature may be selected from 700 ℃ to 900 ℃, the second temperature may be selected from 800 ℃ to 1300 ℃.
또한, 상기 제2온도에 의한 증발 및 염소화금속 제거공정은 진공, 불활성 가스 분위기 또는 진공 분위기와 불활성 가스분위기를 교대로 가하면서 진행되는 것일 수 있다.In addition, the step of evaporating and removing the chlorinated metal at the second temperature may be performed by applying a vacuum, an inert gas atmosphere, or a vacuum atmosphere and an inert gas atmosphere alternately.
상기 염소화금속의 제거공정이 불활성 가스 분위기일 경우 그 압력은 500torr 내지 800torr일 수 있다.When the removal process of the metal chloride is an inert gas atmosphere, the pressure may be 500 tortor to 800 torr.
제1온도(T1)로 염소 함유 화합물 가스와 반응시켜 상기 잔류 금속을 염소화 하는 단계에서 상기 반응은 염소함유화합물 가스를 500torr 내지 900torr까지 공급하여 반응시키는 것일 수 있다.In the step of chlorination of the residual metal by reacting with a chlorine-containing compound gas at a first temperature (T 1 ), the reaction may be performed by supplying a chlorine-containing compound gas up to 500 tortor to 900 torr.
또한, 상기 정제된 카본나노튜브에 잔류하는 금속 불순물 전체 함량은 50ppm 이하일 수 있다.In addition, the total amount of metal impurities remaining in the purified carbon nanotubes may be 50 ppm or less.
또한, 상기 카본나노튜브는 코발트(Co)를 포함하는 금속촉매를 사용하여 제조된 것일 수 있으며, 철(Fe), 몰리브덴(Mo), 바나듐(V) 및 크롬(Cr)중 하나 이상의 금속성분을 더 포함하는 것일 수 있다.In addition, the carbon nanotubes may be manufactured using a metal catalyst containing cobalt (Co), and at least one metal component of iron (Fe), molybdenum (Mo), vanadium (V) and chromium (Cr). It may be to include more.
또한, 상기 카본나노튜브는 정제공정 이후 Co함량이 40ppm 이하일 수 있다.In addition, the carbon nanotubes may have a Co content of 40 ppm or less after the purification process.
또한, 상기 카본나노튜브는 유동층 반응기상에서 화학기상증착법(CVD)을 이용하여 제조된 것일 수 있다.In addition, the carbon nanotubes may be prepared by chemical vapor deposition (CVD) on a fluidized bed reactor.
또한, 상기 염소 함유 화합물은 염소(Cl2) 가스 또는 트리클로로메탄(CHCl3) 가스일 수 있다.In addition, the chlorine-containing compound may be chlorine (Cl 2 ) gas or trichloromethane (CHCl 3 ) gas.
본 발명에 따른 카본나노튜브는 고온의 온도조건에서 염소화합물과 반응함으로써, 금속촉매를 사용하는 카본나노튜브의 제조공정에서 발생된 잔류 금속을 제거할 수 있으며, 이로부터 잔류 금속과 같은 불순물을 효과적으로 제거할 수 있다. 특히 비교적 낮은 온도인 제1 온도에서 진행되는 염소가스 처리공정 및 질소(N2) 또는 진공 분위기에서 제2 온도로 진행되는 염소화금속 제거공정은 카본나노튜브에 잔류하는 금속 제거 효율을 증가시킬 수 있으며, 제2공정은 질소 또는 진공 분위기에서 진행됨으로써, 카본나노튜브 내에 잔류하는 염소가 함께 제거될 수 있다. 카본나노튜브의 물성을 더욱 향상시킬 수 있으며, 특히, 열적안정성이 향상되어 산화분해온도가 현저히 상승하는 효과를 나타냄으로써, 난연소재 및 금속복합체로의 사용에 유용하게 사용될 수 있다.The carbon nanotubes according to the present invention can remove residual metals generated in the manufacturing process of carbon nanotubes using a metal catalyst by reacting with a chlorine compound at a high temperature, thereby effectively removing impurities such as residual metals. Can be removed. In particular, the chlorine gas treatment process that proceeds at a relatively low temperature of the first temperature and the metal chlorine removal process that proceeds to nitrogen (N 2 ) or the second temperature in a vacuum atmosphere can increase the metal removal efficiency remaining in the carbon nanotubes. , The second process is carried out in a nitrogen or vacuum atmosphere, the chlorine remaining in the carbon nanotubes can be removed together. The physical properties of the carbon nanotubes can be further improved, and in particular, the thermal stability is improved and the oxidation decomposition temperature is markedly increased, and thus it can be usefully used for use as a flame retardant material and a metal complex.
도 1a 및 도 1b는 CNT의 정제공정 전(비교예 1)과 후(실시예 1)의 SEM 화상을 나타낸 것이다.1A and 1B show SEM images before (Comparative Example 1) and after (Example 1) the CNT purification step.
도 2a 및 2b는 실시예 1 및 비교예 1에 따른 카본나노튜브의 TEM_EDX 결과를 나타낸 그래프이다.2A and 2B are graphs showing TEM_EDX results of carbon nanotubes according to Example 1 and Comparative Example 1. FIG.
본 명세서 및 청구범위에 사용된 용어나 단어는 통상적이거나 사전적인 의미로 한정해서 해석되어서는 안되며, 발명자는 그 자신의 발명을 가장 최선의 방법으로 설명하기 위해 용어의 개념을 적절하게 정의할 수 있다는 원칙에 입각하여 본 발명의 기술적 사상에 부합하는 의미와 개념으로 해석되어야만 한다.The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best describe their invention. Based on the principle, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.
이하, 본 발명을 상세히 설명하기로 한다.Hereinafter, the present invention will be described in detail.
본 발명의 바람직한 구현예에 따른 카본나노튜브는,Carbon nanotubes according to a preferred embodiment of the present invention,
카본나노튜브에 잔류하는 금속을 진공 또는 불활성 분위기에서 제1온도로 염소 함유 화합물과 반응시켜 상기 잔류 금속을 염소화 하는 단계; 및Chlorinating the residual metal by reacting the metal remaining in the carbon nanotubes with a chlorine-containing compound at a first temperature in a vacuum or inert atmosphere; And
상기 제1온도 보다 높은 온도의 제2온도에서 상기 염소화된 잔류 금속을 증발 및 제거하는 단계; Evaporating and removing the chlorinated residual metal at a second temperature above the first temperature;
를 포함하는 카본나노튜브의 정제방법을 제공한다.It provides a method for purifying carbon nanotubes comprising a.
본 발명은 제조된 카본나노튜브에서 제조공정에 사용된 금속 촉매로부터 발생된 잔류금속을 제거함에 있어서, 염소 함유 화합물과 고온에서 반응시켜 상기 잔류금속을 염소화하여 증발시키는 방법을 이용하며, 이러한 방법을 이용하여 카본나노튜브를 정제함으로써 잔류금속과 같은 금속 불순물에 의한 물성저하가 개선될 수 있다.The present invention uses a method of removing the residual metal generated from the metal catalyst used in the manufacturing process in the carbon nanotubes prepared, by reacting with a chlorine-containing compound at a high temperature to chlorinate the residual metal to evaporate. By purifying the carbon nanotubes by using the physical properties can be improved by metal impurities such as residual metal.
일 실시예에 따르면, 상기 제1온도가 700℃ 내지 1000℃에서 선택되고, 상기 제2 온도가 800℃ 내지 1500℃에서 선택되는 것일 수 있다. According to one embodiment, the first temperature may be selected from 700 ℃ to 1000 ℃, the second temperature may be selected from 800 ℃ to 1500 ℃.
또한, 상기 정제과정을 거친 카본나노튜브에 잔류하는 금속 불순물 함량은 정제 전보다 100배 내지 1000배 이상 감소할 수 있으며, 즉 잔류하는 거의 대부분의 금속이 제거된다고 볼 수 있으며, 이는 염소화된 금속은 비점이 금속에 비해 낮은 특성을 이용하여, 염소화공정을 거쳐 액화 또는 기상의 금속을 보다 높은 온도로 모두 증발시키는 원리를 이용하는 것 일 수 있으며, 이는 기상의 고온반응을 이용하는 것이므로 제조된 카본나노튜브에는 어떠한 물리적 손상도 입히지 않는 장점이 있다.In addition, the metal impurity content remaining in the carbon nanotubes after the purification process may be reduced to 100 to 1000 times or more than before purification, that is, almost all of the metal remaining can be removed, which is the boiling point of the chlorinated metal By using a lower characteristic than this metal, it may be to use the principle of evaporating all of the liquefied or gaseous metal to a higher temperature through the chlorination process, which is because the high temperature reaction of the gas phase is used, It has the advantage of not causing physical damage.
이하 상기의 카본나노튜브의 정제공정을 보다 구체적으로 설명한다. Hereinafter, the carbon nanotube purification process will be described in more detail.
본 발명에 따르면, 제조된 카본나노튜브에 잔류하는 금속을 진공 또는 불활성 가스 분위기에서 제1온도로 염소 함유 화합물과 반응시켜 상기 잔류 금속을 염소화 하는 단계; 및 상기 제1온도 보다 높은 온도의 제2온도에서 상기 염소화된 잔류 금속을 증발 및 제거하는 단계;를 포함하는 정제방법이 제공된다.According to the present invention, chlorination of the residual metal by reacting the metal remaining in the prepared carbon nanotubes with a chlorine-containing compound at a first temperature in a vacuum or inert gas atmosphere; And evaporating and removing the chlorinated residual metal at a second temperature higher than the first temperature.
일 실시예에 따르면, 상기 염소 함유 화합물은 염소(Cl2) 또는 트리클로로메탄(CHCl3) 가스일 수 있다. 염소 함유 화합물은 카본나노튜브와 반응성이 낮기 때문에 제조된 카본나노튜브에 대한 손상을 보다 감소시킬 수 있다.According to one embodiment, the chlorine-containing compound may be chlorine (Cl 2 ) or trichloromethane (CHCl 3 ) gas. Since the chlorine-containing compound has low reactivity with the carbon nanotubes, damage to the carbon nanotubes manufactured may be further reduced.
상기 금속의 염소화가 일어나는 제1온도(T1)는 700℃ 내지 1000℃ 일 수 있으며, 보다 바람직하게는 700℃ 내지 900℃일 수 있다. 700℃ 미만의 온도에서는 탄소 재료 중의 촉매 금속 등의 금속 불순물이 염소화 반응이 원활하지 않을 수 있다.A first temperature of the metal chlorination takes place (T 1) may be a 700 ℃ to 1000 ℃, may be more preferably 700 ℃ to 900 ℃. At temperatures below 700 ° C., chlorination of metal impurities such as catalyst metals in the carbon material may not be smooth.
상기 금속의 염소화공정의 후의 가열공정은 제1온도(T1)보다 높은 온도인 제2온도(T2)에서 수행되며, 구체적으로 T2는, T1+100℃ 이상의 온도일 수 있으며, 바람직하게는 T1+100℃ 이상의 온도일 수 있다. 상기 제2 온도는 800℃ 내지 1500℃ 범위일 수 있으며, 바람직하게는 900℃ 내지 1400℃인 것이 바람직하다. 상기 가열 공정이 900℃ 이하 또는 제1온도 보다 낮은 온도에서 진행될 경우 염소화된 금속의 제거반응이 원활하지 않아 잔류 금속 및 염소화된 금속이 카본나노튜브에 잔류하여 불순물로 작용할 수 있어, 이는 카본나노튜브의 물성을 저하시킬 수 있다. 또한, 1500℃ 이상의 온도에서는 잔류금속에 의한 촉매 흑연화가 발생하여, 금속의 제거가 용이하지 않을 수 있다.The heating step after the chlorination of the metal is performed at a second temperature T 2 , which is higher than the first temperature T 1 , and specifically, T 2 may be a temperature of T 1 + 100 ° C. or higher. Preferably a temperature of T 1 + 100 ° C. or higher. The second temperature may range from 800 ° C to 1500 ° C, preferably 900 ° C to 1400 ° C. When the heating process is performed at a temperature below 900 ° C. or lower than the first temperature, the removal reaction of chlorinated metal is not smooth and residual metal and chlorinated metal may remain in carbon nanotubes to act as impurities, which is carbon nanotubes. Can lower the physical properties. In addition, catalyst graphitization by residual metal may occur at a temperature of 1500 ° C. or higher, and metal removal may not be easy.
또한, 상기 제1온도에서 수행되는 염소화 반응은 약 10분 내지 1시간 동안 유지시킴으로써 잔류금속의 염소화 공정이 보다 완전히 이루어지게 할 수 있으며, 총 유량은 충전된 카본나노튜브 및 반응기의 크기에 따라 조절할 수 있다. In addition, the chlorination reaction carried out at the first temperature may be maintained for about 10 minutes to 1 hour to more fully chlorination of the residual metal, the total flow rate is adjusted according to the size of the carbon nanotubes and the reactor Can be.
또한, 상기 염소화 공정은 상기 염소함유화합물 가스를 500torr 내지 900torr의 압력까지 공급하여 이루어지는 것일 수 있으며, 바람직하게는 600torr 내지 800torr, 보다 바람직하게는 600torr 내지 700torr의 압력에서 이루어지는 것일 수 있다. In addition, the chlorination process may be performed by supplying the chlorine-containing compound gas to a pressure of 500 tortor to 900torr, preferably 600torr to 800torr, more preferably 600torr to 700torr.
상기 염소화 공정 이후 제2온도에서의 염소화금속 증발 및 제거반응은 불활성 가스 또는 진공 분위기에서 30 분 내지 300 분간 수행하는 것일 수 있으며, 이는 카본나노튜브에 영향을 주지 않고 염소화된 잔류금속만을 제거할 수 있는 범위여야 한다. 또한, 염소화금속 증발 및 제거반응은 진공 분위기 및 불활성 가스 분위기를 교대로 형성시키면서 진행될 수 있으며, 이는 제거 효율을 더 높일 수 있다. After the chlorination process, the metal chlorination evaporation and removal reaction at the second temperature may be performed for 30 minutes to 300 minutes in an inert gas or vacuum atmosphere, and this may remove only the chlorinated residual metal without affecting carbon nanotubes. Must be in the range In addition, the metal chlorine evaporation and removal reaction may proceed while alternately forming a vacuum atmosphere and an inert gas atmosphere, which may further increase the removal efficiency.
또한, 상기 잔류금속의 염소화 반응은 진공 또는 불화성 가스 분위기에서 일어나는 것일 수 있다. 보다 구체적으로, 카본나노튜브가 충전된 반응기 또는 반응로를 진공 또는 질소분위기로 하여 제1온도로 승온한 뒤 염소 함유 화합물 가스를 투입함으로써 잔류금속을 염소화 시키는 반응을 진행될 수 있다. 이때, 제1온도에서 이루어지는 염소화 공정에서는 주로 금속의 염소화 반응만이 일어나는 것일 수 있으며, 염소화된 잔류금속의 증발에 의한 제거반응은 주로 제2온도에서 일어날 수 있다. 이때, 잔류금속의 증발 및 제거 공정은 염소 함유 화합물의 투입을 중단하고 다시 반응로 또는 반응기 내부를 진공분위기로 전환하여 진행함으로써, 염소화금속의 증발이 보다 원활히 일어날 수 있다.In addition, the chlorination of the residual metal may occur in a vacuum or fluorinated gas atmosphere. More specifically, the reaction in which the residual metal is chlorinated by adding a chlorine-containing compound gas after heating the carbon nanotube-filled reactor or reactor to a first temperature in a vacuum or nitrogen atmosphere. In this case, in the chlorination process performed at the first temperature, only the chlorination reaction of the metal may occur, and the removal reaction by evaporation of the chlorinated residual metal may occur mainly at the second temperature. At this time, the step of evaporation and removal of the residual metal is to stop the addition of the chlorine-containing compound and proceed again by converting the reaction furnace or the inside of the reactor into a vacuum atmosphere, the evaporation of the metal chloride may occur more smoothly.
이때, 상기 진공 분위기는 1torr이하의 압력을 의미하는 것이며, 상기 불활성 가스는 질소(N2), 아르곤(Ar)와 같은 불활성 기체를 의미한다. In this case, the vacuum atmosphere means a pressure of 1 torr or less, and the inert gas means an inert gas such as nitrogen (N 2 ) or argon (Ar).
또한, 상기 증발 및 염소화 금속 제거 반응이 일어나는 제2공정은 진공 또는 불활성 기체를 500torr 내지 800torr, 바람직하게는 600 내지 700torr까지 공급하여 진행되는 것일 수 있다. In addition, the second step in which the evaporation and chlorinated metal removal reaction occurs may be performed by supplying a vacuum or inert gas to 500 tortor, preferably 600 to 700torr.
또한, 제2 온도로 진행되는 염소화금속 및 염소 화합물 제거 및 증발 공정은 진공 및 불활성 가스 분위기가 교대로 가해질 수 있으며, 펄스(pulse) 형태로 압력이 가해질 수 있다. 구체적으로 1 torr까지 진공을 형성한 뒤 일정 시간 후 다시 불활성 가스를 투입하여 500 torr까지 압력을 가한 뒤 다시 진공을 형성하는 공정을 반복하는 것일 수 있으며, 이러한 공정으로부터 제1공정에서 반응되지 않고 잔류되어 있던 잔류금속까지 제거될 수 있어 정제 효율이 보다 증가 할 수 있다.In addition, the metal chloride and chlorine compound removal and evaporation processes proceeding to the second temperature may be alternately applied with a vacuum and an inert gas atmosphere, and may be pressured in the form of a pulse. Specifically, after the vacuum is formed up to 1 torr, after a predetermined time, the inert gas is added again, the pressure is applied to 500 torr, and the process of forming the vacuum again may be repeated. Residual metals can be removed so that purification efficiency can be increased.
상기한 방법으로 잔류금속이 제거된 카본나노튜브의 금속 불순물의 전체 함량은 50ppm 이하일 수 있으며, 이러한 카본나노튜브의 금속불순물 ICP분석을 통해 측정될 수 있다. 일 실시예에 따르면, 상기 카본나노튜브는 코발트(Co), 철(Fe) 등의 금속을 주성분으로 포함하는 금속 촉매를 사용하는 것일 수 있으며, 이때, 정제 후 상기 주성분 금속의 함량은 각각 40ppm 이하일 수 있으며, 총 함량은 50ppm 이하일 수 있다.The total content of the metal impurities of the carbon nanotubes from which the residual metal is removed by the above method may be 50 ppm or less, and may be measured through the metal impurity ICP analysis of the carbon nanotubes. According to one embodiment, the carbon nanotubes may be to use a metal catalyst containing a metal such as cobalt (Co), iron (Fe) as a main component, in this case, the content of the main component metal after purification is less than 40ppm each The total content may be 50 ppm or less.
또한, 본 발명에 따른 정제공정이 후 주성분 이외의 금속의 함량이 1ppm 이하로 측정될 수 있으며, 예를 들면, 철(Fe), 몰리브덴(Mo), 크롬(Cr) 및 바나듐(V)의 함량이 각각 5ppm 이하, 바람직하게는 각각 1ppm 이하일 수 있다.In addition, after the purification process according to the present invention, the content of the metal other than the main component may be measured to 1 ppm or less, for example, the content of iron (Fe), molybdenum (Mo), chromium (Cr), and vanadium (V). Each of these may be 5 ppm or less, preferably 1 ppm or less, respectively.
상기와 같은 카본나노튜브 정제방법은 카본나노튜브의 손상이나 절단이 생기거나 카본나노튜브가 비정질의 탄소물질로 고화하는 것을 억제하면서, 촉매금속과 같은 잔류금속을 효과적으로 없앨 수 있을 뿐만 아니라 초음파를 사용하지 않고 정제할 수 있어, 카본나노튜브에 물리적 손상이나 절단이 생기는 것을 억제할 수 있음으로써, 기계적 특성 및 물성특성이 향상된 카본나노튜브를 제공할 수 있으며, 특히 열적안정성에 있어서 현저히 향상된 카본나노튜브를 제공할 수 있다.The carbon nanotube purification method as described above can effectively remove residual metals such as catalytic metals while using ultrasonic waves while suppressing damage or cutting of carbon nanotubes or solidifying carbon nanotubes to amorphous carbon materials. It can be purified without being able to suppress the physical damage or cutting of the carbon nanotubes, thereby providing a carbon nanotubes with improved mechanical and physical properties, in particular carbon nanotubes significantly improved in thermal stability Can be provided.
본 발명에 따른 카본나노튜브는 담지촉매를 이용하여 탄소 공급원의 분해를 통한 화학적 기상 합성법(CVD)으로 카본나노튜브를 성장시켜 제조된 것일 수 있으며, 상기 담지 촉매에 담지된 촉매 금속은 카본나노튜브의 성장을 촉진시키는 물질이면 특별히 제한되지 않는다.The carbon nanotubes according to the present invention may be prepared by growing carbon nanotubes by chemical vapor deposition (CVD) through decomposition of a carbon source using a supported catalyst, and the catalyst metal supported on the supported catalyst is carbon nanotubes. It will not be restrict | limited in particular, if it is a substance which accelerates growth of.
이러한 촉매 금속으로서는 예를 들면, IUPAC이 1990년에 권고한 18족형 원소 주기율표의 3 내지 12족으로 이루어진 군으로부터 선택되는 적어도 1종의 금속을 들 수 있다. 그 중에서도 3, 5, 6, 8, 9, 10족으로 이루어지는 군으로부터 선택되는 적어도 1종의 금속이 바람직하며, 철(Fe), 니켈(Ni), 코발트(Co), 크롬(Cr), 몰리브덴(Mo), 텅스텐(W), 바나듐(V), 티타늄(Ti), 루테늄(Ru), 로듐(Rh), 팔라듐(Pd), 백금(Pt) 및 희토류 원소로부터 선택되는 적어도 1종의 금속이 특히 바람직하다. 또한, 이들 촉매로서 작용하는 금속 원소를 함유하는 화합물, 즉 촉매 금속 전구체로서는 촉매 금속의 질산염, 황산염, 탄산염 등의 무기염류, 초산염 등의 유기염, 아세틸아세톤 착체 등의 유기 착체, 유기 금속 화합물 등 촉매 금속을 함유하는 화합물이면 특별히 한정되지 않는다.Examples of such a catalytic metal include at least one metal selected from the group consisting of Groups 3 to 12 of the Group 18 type periodic table recommended by IUPAC in 1990. Among them, at least one metal selected from the group consisting of Groups 3, 5, 6, 8, 9, and 10 is preferable, and iron (Fe), nickel (Ni), cobalt (Co), chromium (Cr), and molybdenum are preferred. At least one metal selected from (Mo), tungsten (W), vanadium (V), titanium (Ti), ruthenium (Ru), rhodium (Rh), palladium (Pd), platinum (Pt) and rare earth elements Particularly preferred. Moreover, as a compound containing metal elements which act as these catalysts, ie, a catalyst metal precursor, inorganic salts, such as nitrate, sulfate, and carbonate of a catalyst metal, organic salts, such as acetate, organic complexes, such as an acetylacetone complex, an organometallic compound, etc. It will not specifically limit, if it is a compound containing a catalyst metal.
이들 촉매 금속 및 촉매 금속 전구체 화합물을 2종 이상 사용함으로써 반응 활성을 조절하는 것은 널리 알려져 있다. 예를 들어, 철(Fe), 코발트(Co) 및 니켈(Ni)로부터 선택되는 하나 이상의 원소와 티타늄(Ti), 바나듐(V) 및 크롬(Cr)으로부터 선택되는 원소와 몰리브덴(Mo) 및 텅스텐(W)으로부터 선택되는 원소를 조합한 것을 예시할 수 있다. 바람직하게는 코발트(Co)를 주성분으로 하며, 철(Fe), 몰리브덴(Mo), 크롬(Cr) 및 바나듐(V)에서 선택되는 하나 이상의 금속을 더 포함하는 금속 촉매일 수 있다.It is well known to control reaction activity by using 2 or more types of these catalyst metals and catalyst metal precursor compounds. For example, at least one element selected from iron (Fe), cobalt (Co) and nickel (Ni), and an element selected from titanium (Ti), vanadium (V) and chromium (Cr) and molybdenum (Mo) and tungsten What combined the element chosen from (W) can be illustrated. Preferably, the metal catalyst may further include one or more metals selected from cobalt (Co) and selected from iron (Fe), molybdenum (Mo), chromium (Cr), and vanadium (V).
상기 카본나노튜브 생성 단계에서 사용되는 촉매는 구체적으로 촉매활성금속 전구체인 Co(NO3)2-6H2O, (NH4)6Mo7O24-4H2O, Fe(NO3)2-6H2O 또는 (Ni(NO3)2-6H2O) 등을 증류수에 용해시킨 다음, 이를 Al2O3, SiO2 또는 MgO 등의 담체에 습식 함침(wet impregnation)시켜 제조한 것일 수 있다.The catalyst used in the carbon nanotube generation step is specifically a catalytically active metal precursor, Co (NO 3 ) 2 -6H 2O , (NH 4 ) 6 Mo 7 O 24 -4H 2 O, Fe (NO 3 ) 2 -6H 2 O or (Ni (NO 3) 2 -6H 2 O) was dissolved in distilled water, etc., and then, this Al 2 O 3, by wet impregnation (wet impregnation) of the support, such as SiO 2 or MgO may be manufactured.
또한, 상기 촉매는 구체적인 예로 촉매활성금속 전구체와 Al(OH)3, Mg(NO3)2 또는 콜로이달 실리카(colloidal silica) 등의 담체를 함께 초음파로 처리하여 제조된 것일 수 있다.In addition, the catalyst may be prepared by ultrasonically treating a catalytically active metal precursor with a carrier such as Al (OH) 3 , Mg (NO 3 ) 2, or colloidal silica.
또한, 상기 촉매는 물에 촉매활성금속 전구체가 원활하게 용해될 수 있도록 시트르산(citric acid), 타르타르산(tartaric acid) 등의 킬레이트 에이전트를 사용하여 졸겔법으로 제조된 것이거나, 물에 잘 용해되는 촉매활성금속 전구체를 공침(co-precipitation)시켜 제조된 것일 수 있다.In addition, the catalyst is prepared by the sol-gel method using a chelating agent such as citric acid (citric acid), tartaric acid (tartaric acid), so that the catalytically active metal precursor in water can be dissolved smoothly, or a catalyst that is well dissolved It may be prepared by co-precipitation of the active metal precursor.
본 발명의 방법에 있어서 상기 담지 촉매와 탄소 함유 화합물을 가열영역하에 접촉시킴으로써 제조될 수 있다.In the method of the present invention, the supported catalyst and the carbon-containing compound can be prepared by contacting under a heating zone.
촉매 제조과정에 있어서, 함침법을 이용한 담지 촉매를 사용하는 것이 바람직한데, 이는 담지 촉매가 사용되는 경우 촉매 자체의 벌크 밀도(bulk density)가 공침 촉매에 비해 높고 공침 촉매와 달리 10 마이크론 이하의 미분이 적어 유동화 과정에서 발생할 수 있는 마모(attrition)에 의한 미분발생 가능성을 줄일 수 있으며, 촉매 자체의 기계적 강도도 우수하여 반응기 운전을 안정하게 할 수 있는 효과를 갖기 때문이다.In the preparation of the catalyst, it is preferable to use a supported catalyst by impregnation method, in which the bulk density of the catalyst itself is higher than that of the coprecipitation catalyst and fine powder of 10 microns or less unlike the coprecipitation catalyst when the supported catalyst is used. This is because it is possible to reduce the possibility of fine powder due to wear (attrition) that can occur in the fluidization process, and because the mechanical strength of the catalyst itself is also excellent, it has the effect of stabilizing the operation of the reactor.
본 발명에서 사용될 수 있는 알루미늄계 지지체는 Al2O3, AlO(OH) 및 Al(OH)3로 이루어지는 그룹으로부터 선택되는 하나 이상일 수 있으며, 바람직하게는 알루미나(Al2O3)일 수 있다. 또한, 상기 알루미늄(Al)계 지지체에 ZrO2, MgO 및 SiO2로 이루어지는 그룹에서 선택되는 하나 이상을 추가로 포함할 수 있다. 상기 알루미늄(Al)계 지지체는 구형 또는 포테이토형의 형상을 가지고, 단위 질량 또는 부피당 비교적 높은 표면적을 갖도록 다공성 구조, 분자체 구조, 벌집 구조, 또 다른 적합한 구조를 갖는 물질로 구성되는 것일 수 있다.The aluminum-based support that can be used in the present invention may be one or more selected from the group consisting of Al 2 O 3 , AlO (OH) and Al (OH) 3 , and preferably may be alumina (Al 2 O 3 ). In addition, the aluminum (Al) -based support may further include one or more selected from the group consisting of ZrO 2 , MgO and SiO 2 . The aluminum (Al) -based support may have a spherical or potato shape, and may be made of a material having a porous structure, a molecular sieve structure, a honeycomb structure, or another suitable structure to have a relatively high surface area per unit mass or volume.
일 구현예에 따르면, 본 발명에 따른 CNT 합성용 담지촉매의 제조방법은,According to one embodiment, the preparation method of the supported catalyst for CNT synthesis according to the present invention,
(1) 촉매성분 전구체 및 활성성분 전구체를 포함하는 금속 수용액에 지지체를 혼합하여 담지촉매 전구체 함유 수용액을 형성하는 단계;(1) mixing a support with a metal aqueous solution containing a catalyst component precursor and an active component precursor to form a supported catalyst precursor-containing aqueous solution;
(2) 상기 담지촉매 전구체 함유 수용액을 숙성 함침시켜 혼합물을 수득하는 단계;(2) aging and impregnating the supported catalyst precursor-containing aqueous solution to obtain a mixture;
(3) 상기 혼합물을 진공건조하여 상기 지지체 표면에 상기 촉매성분 및 활성성분을 코팅하는 단계; 및(3) vacuum drying the mixture to coat the catalyst component and active ingredient on the support surface; And
(4) 상기 진공건조에 의해 얻어진 결과물을 소성하여 담지촉매를 형성하는 단계;를 포함하는 방법으로 제조될 수 있다.(4) calcining the resultant obtained by the vacuum drying to form a supported catalyst; can be prepared by a method comprising a.
상기 촉매를 이용하여 탄소 공급원의 분해를 통한 화학적 기상 합성법으로 카본나노튜브를 성장시키는 화학적 기상 합성법으로 카본나노나노튜브를 제조할 수 있다.Carbon nanotubes can be prepared by chemical vapor phase synthesis in which carbon nanotubes are grown by chemical vapor phase synthesis through decomposition of a carbon source using the catalyst.
구체적으로, 상기 화학적 기상 합성법은 상기 카본나노튜브 촉매를 유동층 반응기에 투입하고 500℃ ~ 900℃ 하에 탄소수 1~4의 포화 또는 불포화 탄화수소에서 선택된 1 이상의 탄소 공급원, 또는 상기 탄소공급원과 수소 및 질소의 혼합가스를 주입하여 실시될 수 있다. 상기 카본나노튜브 제조용 촉매에 탄소공급원을 주입하여 카본나노튜브를 성장시키는 단계는 30분 내지 8시간 동안 수행될 수 있다.Specifically, the chemical vapor phase synthesis method is a carbon nanotube catalyst is introduced into a fluidized bed reactor and at least one carbon source selected from saturated or unsaturated hydrocarbons having 1 to 4 carbon atoms at 500 ℃ ~ 900 ℃, or the carbon source and hydrogen and nitrogen It can be carried out by injecting a mixed gas. The carbon nanotubes are grown by injecting a carbon source into the catalyst for preparing carbon nanotubes, which may be performed for 30 minutes to 8 hours.
상기 탄소공급원은 탄소수 1 내지 4의 포화 또는 불포화 탄화수소, 예를 들어 에틸렌(C2H4), 아세틸렌(C2H2), 메탄(C2H4), 프로판(C3H8)등 일 수 있으나, 이에 제한되는 것은 아니다. 또한, 수소 및 질소의 혼합가스는 탄소공급원을 운송하며, 카본나노튜브가 고온에서 연소되는 것을 방지하고, 탄소공급원의 분해를 돕는다.The carbon source may be a saturated or unsaturated hydrocarbon having 1 to 4 carbon atoms, such as ethylene (C 2 H 4 ), acetylene (C 2 H 2 ), methane (C 2 H 4 ), propane (C 3 H 8 ), and the like. May be, but is not limited thereto. In addition, the mixed gas of hydrogen and nitrogen transports a carbon source, prevents carbon nanotubes from burning at a high temperature, and assists decomposition of the carbon source.
본 발명에 따른 담지 촉매를 사용하여 제조되는 카본나노튜브는 입도 분포값(Dcnt) 0.5~1.0의 포테이토형(potato) 또는 구형(sphere)의 집합체 형태로 얻어질 수 있다. 예를 들면, 구형 또는 포테이토형의 입상 지지체에 촉매성분 및 활성성분을 함침 및 소성하여 얻은 촉매 또한 형상의 큰 변화가 없이 구형 또는 포테이토형을 가지며, 이러한 촉매 상에 성장된 카본나노튜브 집합체 또한 형상의 큰 변화없이 직경만 커진 구형 또는 포테이토형의 형상을 갖는 것이 또 하나의 특징이다. 여기서 구형 또는 포테이토 형상이란 애스펙트비 1.2 이하의 구형, 타원체형과 같은 3차원 형상을 지칭한다.The carbon nanotubes prepared using the supported catalyst according to the present invention may be obtained in the form of a potato or sphere aggregate having a particle size distribution (D cnt ) of 0.5 to 1.0. For example, a catalyst obtained by impregnating and calcining a catalyst component and an active ingredient in a spherical or potato granular support also has a spherical or potato form without significant change in shape, and the carbon nanotube aggregates grown on such a catalyst also have a shape. Another feature is to have a spherical or potato shape with only a large diameter without a large change of. Here, the spherical or potato shape refers to a three-dimensional shape such as a spherical and ellipsoidal shape having an aspect ratio of 1.2 or less.
상기 카본나노튜브의 입도 분포값(Dcnt)은 하기 식 1로 정의되는 것이다.The particle size distribution value (D cnt ) of the carbon nanotubes is defined by Equation 1 below.
[식 1][Equation 1]
Dcnt= [Dn90-Dn10]/Dn50 Dcnt = [Dn 90 -Dn 10 ] / Dn 50
여기서, Dn90은 CNT를 증류수에 넣고 3시간 방치 후 Microtrac 입도 분석기를 이용하여 흡수(absorbing) 모드에서 90% 기준 하에 측정한 개수 평균 입경이고, Dn10은 10% 기준 하에 측정한 개수 평균 입경, 그리고 Dn50은 50% 기준 하에 측정한 개수 평균 입경이다.Here, Dn 90 is the number average particle diameter measured under 90% in absorbing mode using a Microtrac particle size analyzer after 3 hours of CNT in distilled water, Dn 10 is the number average particle diameter measured under 10%. And Dn 50 is the number average particle diameter measured on a 50% basis.
상기 입도 분포값은 바람직하게는 0.55 ~ 0.95, 더욱 바람직하게는 0.55 ~0.9 일 수 있다.The particle size distribution value may be preferably 0.55 to 0.95, more preferably 0.55 to 0.9.
본 발명에 있어서, 상기 카본나노튜브는 편평률이 0.9 ~ 1 인 번들 타입 또는 비 번들 타입일 수 있는데, 본 발명에서 사용하는 용어 '번들(bundle)'이란 달리 언급되지 않는 한, 복수개의 카본나노튜브가 나란하게 배열 또는 뒤엉켜있는, 다발(bundle) 혹은 로프(rope) 형태를 지칭한다. '비 번들(non bundle 또는 entangled) 타입' 이란 이와 같은 다발 혹은 로프 형태와 같은 일정한 형상이 없는 형태이다, 번들 타입인 경우 CNT 번들은 1 내지 50㎛의 직경을 가질 수 있다. In the present invention, the carbon nanotubes may be a bundle type or a non-bundle type having a flatness of 0.9 to 1, and the term 'bundle' used in the present invention, unless otherwise stated, refers to a plurality of carbon nanotubes. It refers to a bundle or rope form, in which the tubes are arranged or intertwined side by side. 'Non-bundle (entangled) type' is a form without a certain shape, such as a bundle or rope shape, in the case of a bundle type CNT bundle may have a diameter of 1 to 50㎛.
상기 편평률은 하기 식 2로 정의된 것이다.The flatness is defined by Equation 2 below.
[식 2] [Equation 2]
편평률 = CNT의 중심을 관통하는 최단 직경 / CNT의 중심을 관통하는 최대직경. Flatness ratio = shortest diameter through the center of CNT / maximum diameter through the center of CNT.
본 발명에 있어서, 상기 카본나노튜브는 벌크 밀도(bulk density)가 80 ~250kg/m3인 것을 특징으로 한다. 구체적으로 상기 벌크 밀도는 하기 식 3으로 정의된것으로, 카본나노튜브의 밀도 분포가 본 발명 특유의 범위를 제공할 수 있다.In the present invention, the carbon nanotubes are characterized in that the bulk density (bulk density) is 80 ~ 250kg / m 3 . Specifically, the bulk density is defined by the following Equation 3, the density distribution of the carbon nanotubes can provide a range unique to the present invention.
[식 3] [Equation 3]
벌크 밀도= CNT 무게(kg) / CNT 부피(m3)Bulk Density = CNT Weight (kg) / CNT Volume (m 3 )
본 발명에 있어서, 상기 카본나노튜브는 평균입경은 100 ~ 800㎛이고, 카본나노튜브의 가닥 직경이 10 ~ 50nm 일 수 있다.In the present invention, the carbon nanotubes may have an average particle diameter of 100 to 800 µm, and a strand diameter of the carbon nanotubes may be 10 to 50 nm.
상기와 같은 성질을 갖는 카본나노튜브에 미분 또는 불순물 형태로 잔류하는 금속성분을 고온의 분위기에서 염소 화합물과 반응시켜 금속염소화물을 형성시킴으로써, 그 비점을 낮출 수 있으며, 상기 금속 염소화물의 비점 이상의 온도 조건에서 증발 및 제거시키는 공정을 이용하여 상기 카본나노튜브를 정제할 수 있으며, 이러한 방법으로 제조된 카본나노튜브는 물성특성이 향상될 수 있으며, 특히 열안정성이 향상됨으로써, 난연재, 금속복합재 등 고온의 환경에 사용되는 탄소 복합소재에 유용하게 사용될 수 있다. By reacting a metal component remaining in the form of fine powder or impurity in a carbon nanotube having the above properties with a chlorine compound in a high temperature atmosphere to form a metal chlorine, the boiling point can be lowered, and the temperature above the boiling point of the metal chloride The carbon nanotubes may be purified using a process of evaporation and removal under conditions, and the carbon nanotubes manufactured by this method may have improved physical properties, and in particular, thermal stability may be improved, such as high temperature flame retardants and metal composite materials. It can be usefully used for carbon composites used in the environment.
이하에서는 실시예 및 비교예를 들어 본 발명을 상세히 설명하나 본 발명이 이에 한정되는 것은 아니며, 본 발명을 보다 구체적으로 설명하기 위한 예시에 불과한 것이다.Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto, and the present invention is merely illustrative for describing the present invention in more detail.
비교예Comparative example 1 : Co/Fe- 1: Co / Fe- CNTCNT 제조 Produce
CNT합성용 Co/Fe 함유 금속촉매를 이용하여 실험실 규모의 고정층 반응장치에서 카본나노튜브 합성을 시험하였다. 구체적으로 상기 공정에서 제조된 CNT 합성용 촉매를 직경 55 mm의 내경을 갖는 석영관의 중간부에 장착한 후, 질소 분위기에서 650℃까지 승온한 다음 유지시키고, 수소가스를 60 sccm의 유속으로 흘리면서 2시간 동안 합성하여 인탱글(비번들)타입의 본나노튜브 응집체를 합성하였다. 카본나노튜브의 형상을 도 1에 나타내었다.Carbon nanotube synthesis was tested in a laboratory scale fixed bed reactor using a Co / Fe-containing metal catalyst for CNT synthesis. Specifically, the catalyst for synthesizing CNT prepared in the above process was mounted in the middle of a quartz tube having an internal diameter of 55 mm, and then heated up to 650 ° C. in a nitrogen atmosphere and maintained therein, while flowing hydrogen gas at a flow rate of 60 sccm. Synthesis was carried out for 2 hours to synthesize an entangled (non-bundle) type nanotube aggregate. The shape of the carbon nanotubes is shown in FIG. 1.
실시예Example 1 -  One - 카본나노튜브의Carbon nanotube 정제 refine
비교예 1 에서 제조된 카본나노튜브 20g을 소성로에 배치했다. 소성로를 1torr까지 진공 배기해 내부를 900℃까지 온도상승시켰다. 다음으로, 염소(Cl2) 가스를 680torr까지 공급했다. 이 후, 1200℃로 승온시켜 2시간 동안 진공 분위기에서 유지한 후 진공 냉각했다.20 g of carbon nanotubes prepared in Comparative Example 1 were placed in a firing furnace. The kiln was evacuated to 1 torr and the temperature was raised to 900 ° C. Next, chlorine (Cl 2 ) gas was supplied to 680 torr. Thereafter, the temperature was raised to 1200 ° C. and maintained in a vacuum atmosphere for 2 hours, followed by vacuum cooling.
정제된 제1카본나노튜브의 형상을 도 1에 나타내었다.The shape of the purified first carbon nanotubes is shown in FIG. 1.
상기 카본나노튜브의 정제 전 후의 구성원소 변화 관찰을 위해 TEM_EDX를 측정하여 도 2에 나타내었다.TEM_EDX was measured and observed in FIG. 2 for observing the change of the element before and after purification of the carbon nanotubes.
실시예Example 2  2
상기 제조예 1에서 제조된 카본나노튜브 20g를 소성로에 배치했다. 소성로를 1torr까지 내부를 질소(N2) 분위기로 퍼지한 후 750℃까지 온도를 상승시켰다. 다음으로, CHCl3 가스를 680torr까지 공급했다. 이 후, 900℃로 승온시켜 2시간 동안 질소 가스 분위기에서 유지한 후 진공 냉각했다.20 g of carbon nanotubes prepared in Preparation Example 1 were placed in a firing furnace. The furnace was purged with nitrogen (N 2 ) atmosphere up to 1 torr, and then the temperature was raised to 750 ° C. Next, CHCl 3 gas was supplied to 680 torr. Thereafter, the temperature was raised to 900 ° C. and maintained in a nitrogen gas atmosphere for 2 hours, followed by vacuum cooling.
비교예Comparative example 2 2
상기 제조예 1에서 제조된 카본나노튜브 20g를 소성로에 배치했다. 소성로를 1torr까지 내부를 질소(N2) 분위기로 퍼지한 후 650℃까지 온도를 상승시켰다. 다음으로, CHCl3 가스를 680torr까지 공급했다. 이 후, 650℃의 동일한 온도에서 2시간 동안 유지한 후 진공 냉각했다.20 g of carbon nanotubes prepared in Preparation Example 1 were placed in a firing furnace. The furnace was purged with nitrogen (N 2 ) atmosphere up to 1 torr, and then the temperature was raised to 650 ° C. Next, CHCl 3 gas was supplied to 680 torr. Thereafter, the mixture was kept at the same temperature of 650 ° C. for 2 hours and then vacuum cooled.
상기 실시예 및 비교예의 카본나노튜브를 ICP(Inductively coupled plasma spectrometry)로 분석하여, 카본나노튜브 내에 존재하는 Fe, Co, Mo, V, Cr의 함량을 측정하여 하기 표 1에 나타내었다.The carbon nanotubes of the examples and the comparative examples were analyzed by inductively coupled plasma spectrometry (ICP), and the contents of Fe, Co, Mo, V, and Cr in the carbon nanotubes were measured and shown in Table 1 below.
구분division Cl 원료Cl Raw material 처리온도(℃)Treatment temperature (℃) 반응 분위기Reaction atmosphere ICP(ppm)ICP (ppm)
T1 T 1 T2 T 2 FeFe CoCo MoMo VV CrCr
실시예 1Example 1 Cl2 Cl 2 900900 12001200 진공vacuum <1<1 <10<10 <1<1 <1<1 <1<1
실시예 2Example 2 CHCl3 CHCl 3 750750 900900 N2 N 2 <1<1 4040 <1<1 <1<1 <1<1
비교예 1Comparative Example 1 미처리Untreated -- -- -- 30003000 42504250 500500 480480 300300
비교예 2Comparative Example 2 CHCl3 CHCl 3 650650 650650 N2 N 2 5050 385385 <1<1 <1<1 <1<1
TEM-EDX 분석 장비를 통하여 비교예1에서 제조된 정제전의 카본나노튜브와 실시예 1에서 제조된 정제된 카본나노튜브의 표면원소를 분석한 결과를 도 2에 나타내었다. 도 2a의 정제 전(비교예 1)의 피크와 정제 후(실시예 1) 도 2b의 피크를 비교하면 도 2a에서 나타난 피크 이외의 피크가 도 2b에서 나타나지 않는 것을 알 수 있으면, 이로써 본 발명에 따른 염소가스 정제공정 이후 정제된 카본나노튜브의 표면에 Cl2 가스가 잔류하지 않는 것을 증명할 수 있다.The results of analyzing the surface elements of the carbon nanotubes before purification prepared in Comparative Example 1 and the purified carbon nanotubes prepared in Example 1 through the TEM-EDX analysis equipment are shown in FIG. 2. Comparing the peak before purification (Comparative Example 1) of FIG. 2A and the peak of FIG. 2B after purification (Example 1), it can be seen that peaks other than those shown in FIG. 2A do not appear in FIG. 2B. Cl 2 on the surface of the purified carbon nanotubes after the chlorine gas purification process according to the It can be proved that no gas remains.
이상으로 본 발명 내용의 특정한 부분을 상세히 기술하였는바, 당업계의 통상의 지식을 가진 자에게 있어서, 이러한 구체적 기술은 단지 바람직한 실시 양태일 뿐이며, 이에 의해 본 발명의 범위가 제한되는 것이 아닌 점은 명백할 것이다. 따라서 본 발명의 실질적인 범위는 첨부된 청구항들과 그것들의 등가물에 의하여 정의된다고 할 것이다.The specific parts of the present invention have been described in detail above, and it is apparent to those skilled in the art that such specific descriptions are merely preferred embodiments, and thus the scope of the present invention is not limited thereto. something to do. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.
본 발명에 따른 카본나노튜브는 고온의 온도조건에서 염소화합물과 반응함으로써, 금속촉매를 사용하는 카본나노튜브의 제조공정에서 발생된 잔류 금속을 제거할 수 있으며, 이로부터 잔류 금속과 같은 불순물을 효과적으로 제거할 수 있어, 카본나노튜브의 물성을 더욱 향상시킬 수 있으며, 특히, 열적안정성이 향상되어 산화분해온도가 현저히 상승하는 효과를 나타냄으로써, 난연소재 및 금속복합체로의 사용에 유용하게 사용될 수 있다.The carbon nanotubes according to the present invention can remove residual metals generated in the manufacturing process of carbon nanotubes using a metal catalyst by reacting with a chlorine compound at a high temperature, thereby effectively removing impurities such as residual metals. Since it can be removed, the physical properties of the carbon nanotubes can be further improved, and in particular, the thermal stability is improved and the oxidation decomposition temperature is markedly increased, and thus it can be usefully used for use as a flame retardant material and a metal complex. .

Claims (14)

  1. 카본나노튜브에 잔류하는 금속을 진공 또는 불활성 가스 분위기에서 제1온도(T1)로 염소 함유 화합물과 반응시켜 상기 잔류 금속을 염소화 하는 단계; 및Chlorinating the residual metal by reacting the metal remaining in the carbon nanotubes with a chlorine-containing compound at a first temperature (T 1 ) in a vacuum or inert gas atmosphere; And
    상기 제1온도(T1) 보다 높은 온도의 제2온도(T2)로 상기 염소화된 잔류 금속을 증발 및 제거하는 단계; Evaporating and removing the chlorinated residual metal at a second temperature (T 2 ) at a temperature higher than the first temperature (T 1 );
    를 포함하는 카본나노튜브의 정제방법.Carbon nanotube purification method comprising a.
  2. 제1항에 있어서,The method of claim 1,
    상기 제2온도(T2)가 T1+100℃ 이상의 온도에서 진행되는 것을 특징으로 하는 카본나노튜브의 정제방법.Purification method of carbon nanotubes, characterized in that the second temperature (T 2 ) is carried out at a temperature of T 1 +100 ℃ or more.
  3. 제1항에 있어서,The method of claim 1,
    상기 제1온도가 700℃ 내지 1000℃ 에서 선택되고, 상기 제2 온도가 800℃ 내지 1500℃에서 선택되는 것인 카본나노튜브의 정제방법.The first temperature is selected from 700 ℃ to 1000 ℃, the second temperature is selected from 800 ℃ to 1500 ℃ purification method of carbon nanotubes.
  4. 제1항에 있어서,The method of claim 1,
    상기 제1온도가 700℃ 내지 900℃이고, 제2온도가 900℃ 내지 1300℃인 온도 조건에서 수행되는 것을 특징으로 하는 카본나노튜브의 정제방법.The first temperature is 700 ℃ to 900 ℃, the second temperature is 900 to 1300 ℃ carbon nanotube purification method, characterized in that carried out at a temperature condition.
  5. 제1항에 있어서,The method of claim 1,
    상기 제2온도에 의한 증발 및 염소화금속 제거공정은 진공, 불활성 가스 분위기 또는 진공 분위기와 불활성 가스분위기를 교대로 가하면서 진행되는 것을 특징으로 하는 카본나노튜브의 정제방법.The process of evaporating and removing the metal chlorine at the second temperature is carried out while applying a vacuum, an inert gas atmosphere, or a vacuum atmosphere and an inert gas atmosphere alternately.
  6. 제5항에 있어서,The method of claim 5,
    상기 염소화금속의 제거공정이 불활성 가스 분위기일 경우 그 압력이 500torr 내지 800torr인 카본나노튜브의 정제방법.When the removal process of the metal chloride is inert gas atmosphere, the pressure is 500torr to 800torr purification method of carbon nanotubes.
  7. 제1항에 있어서,The method of claim 1,
    제1온도(T1)로 염소 함유 화합물 가스와 반응시켜 상기 잔류 금속을 염소화 하는 단계에서 상기 반응은 염소함유화합물 가스를 500torr 내지 900torr까지 공급하여 반응시키는 것인 카본나노튜브의 정제방법.In the step of chlorination of the residual metal by reacting with a chlorine-containing compound gas at a first temperature (T 1 ), the reaction is to supply a chlorine-containing compound gas up to 500torr to 900torr to react the carbon nanotubes.
  8. 제1항에 있어서,The method of claim 1,
    상기 정제된 카본나노튜브에 잔류하는 금속 불순물의 전체 함량이 50ppm 이하인 것을 특징으로 하는 카본나노튜브의 정제방법.The method of purifying carbon nanotubes, characterized in that the total content of metal impurities remaining in the purified carbon nanotubes is 50 ppm or less.
  9. 제1항에 있어서,The method of claim 1,
    상기 카본나노튜브가 코발트(Co)를 포함하는 금속촉매를 사용하여 제조된 것인 카본나노튜브의 정제방법.The carbon nanotube is a purification method of carbon nanotubes prepared using a metal catalyst containing cobalt (Co).
  10. 제9항에 있어서,The method of claim 9,
    상기 카본나노튜브가 철(Fe), 몰리브덴(Mo), 바나듐(V) 및 크롬(Cr)중 하나 이상의 금속성분을 더 포함하는 금속촉매를 사용하여 제조된 것인 카본나노튜브의 정제방법.The carbon nanotube is a purification method of carbon nanotubes prepared using a metal catalyst further comprising at least one metal component of iron (Fe), molybdenum (Mo), vanadium (V) and chromium (Cr).
  11. 제1항에 있어서,The method of claim 1,
    상기 카본나노튜브 정제공정 이 후에 잔류된 철(Fe), 몰리브덴(Mo), 바나듐(V) 및 크롬(Cr) 의 함량이 각각 1ppm 이하인 카본나노튜브의 정제방법.After the carbon nanotube refining process, the iron (Fe), molybdenum (Mo), vanadium (V) and chromium (Cr) content of each carbon nanotube purification method of less than 1ppm.
  12. 제1항에 있어서,The method of claim 1,
    상기 카본나노튜브의 정제공정 이후 Co함량이 40ppm 이하인 카본나노튜브의 정제방법.A method of purifying carbon nanotubes having a Co content of 40 ppm or less after the purification process of the carbon nanotubes.
  13. 제1항에 있어서,The method of claim 1,
    상기 카본나노튜브는 유동층 반응기상에서 화학기상증착법(CVD)를 이용하여 제조된 것인 카본나노튜브의 정제방법.The carbon nanotubes are prepared by chemical vapor deposition (CVD) on a fluidized bed reactor.
  14. 제1항에 있어서,The method of claim 1,
    상기 염소 함유 화합물이 염소(Cl2) 가스 또는 트리클로로메탄(CHCl3) 가스인 것을 특징으로 하는 카본나노튜브의 정제방법.The chlorine-containing compound is chlorine (Cl 2 ) gas or trichloromethane (CHCl 3 ) gas purification method of carbon nanotubes, characterized in that.
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