CN115010116B - Method for preparing high-purity carbon nano tube from coal - Google Patents
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- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
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- C01B32/17—Purification
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Abstract
The invention discloses a method for preparing high-purity carbon nano tubes by coal, which comprises the following steps ofA step of preparing activated coal particles by activating the coal particles, a step of preparing coal-based carbon nanotubes from the activated coal particles, and a step of purifying the coal-based carbon nanotubes. The preparation method of the coal-based carbon nano tube of the invention is that CH 4 And CO 2 By dynamically adjusting CH under atmosphere 4 And CO 2 The ratio of (2) to (c) to (d) to control the preparation process, making the carbon nanotube growth or purification process more trace-able. In addition, the method fully utilizes coal and CO2 resources, and provides a new method for energy conservation, emission reduction and high-value utilization of low-carbon resources.
Description
Technical Field
The invention belongs to the technical field of carbon materials, and particularly relates to a method for preparing high-purity carbon nanotubes from coal.
Background
The coal is the main energy source of China, under the constraint of current resources and environment, the coal industry of China can not only utilize the energy attribute of coal, and under the condition of double-carbon environment, the traditional extensive development mode is urgently needed to be changed, and the utilization efficiency of coal resources is improved.
Carbon nanotubes are tubular carbon molecules with excellent mechanical, electromagnetic, optical and thermodynamic properties and are widely used in various fields. The main methods for preparing the carbon nano tube include an arc discharge method, a laser evaporation method, a plasma method, a chemical vapor deposition method and the like. How to produce carbon nanotubes more efficiently and at lower cost is a great concern today. The current industrial mass production technology of carbon nanotubes is mainly finished by a vapor deposition method, and coal and pyrolysis products thereof can be used as carbon sources in the growth process of the carbon nanotubes, so that the carbon nanotubes can be prepared by taking the coal as a raw material.
Chinese patent CN112723340a discloses a method for preparing carbon nanotubes by modulating low-rank coal, which uses low-rank coal as raw material, first uses subcritical H 2 The O-CO system modulates the structure of the low-rank coal to obtain modified coal, then the modified coal is catalytically pyrolyzed under normal pressure to prepare carbon nanotubes, and finally the carbon nanotubes are subjected to acid washing and ultrasonic separation. The catalyst is nano CaCO 3 、Na 2 CO 3 One or more of CaO or KOH. The method takes long flame coal as a raw material, and obtains carbon nano tubes through modifying coal by a reaction kettle, although pure carbon nano tubes are obtained through acid washing and ultrasonic vibration, the method requires a subcritical system for modifying the coal, has higher requirements on equipment temperature and pressure, requires the pressure and the temperature in the reaction kettle, also requires the isolation of air and ultrasonic separation, and compared with a CO supercritical system, the method adopts a CO supercritical system because CO and water can obtain active H under the supercritical system, and the patent uses a low-temperature and low-pressure carbon dioxide supercritical system for purification.
Chinese patent CN113955742a discloses a process for preparing carbon nanotubes by carbon dioxide-methane reforming technology, which takes methane and carbon dioxide as carbon sources, fully utilizes greenhouse gases (carbon dioxide and methane) as raw materials to the maximum extent, prepares carbon nanotubes with high added value and synthesis gas, and solves the problem of low utilization rate of raw materials in the process of preparing carbon nanotubes. In contrast, the invention is completed by modulating the proportion of carbon dioxide gas in the methane and carbon dioxide gas, when the proportion of carbon dioxide is higher, the process is a carbon nanotube purifying process, when the proportion of carbon dioxide is lower, the process is a carbon nanotube preparing process, and simultaneously, a large amount of carbon deposition is generated; if 2 processes are circulated, carbon deposition can be effectively reduced, and the growth of the carbon nano tube can be promoted.
Chinese patent CN108514872a discloses a preparation method of alkali metal catalyst for carbon nanotubes, which comprises preparing KOH or NaOH alkali solution, immersing catalyst carrier in KOH or NaOH alkali solution, stirring and immersing for 4-24h in magnetic stirrer, suction filtering, drying the solid residue in oven at 100-105 ℃ for 6-15h, and roasting at high temperature to obtain the alkali metal catalyst for carbon nanotubes. The main components of the carbon nano tube alkali metal catalyst obtained by the method are KOH and NaOH, and the invention uses the potassium hydrogen catalyst as a hydroxyl corrosion inhibitor and provides an alkaline environment to promote the catalysis of K ions.
As can be seen from the published literature, the carbon nanotube product prepared by the method in the prior art contains more carbon deposition and residual tar impurities, has lower purity and poorer oxidation resistance, so that the preparation method of the high-purity coal-made carbon nanotube with high efficiency, simplicity and low cost is urgently needed to be developed.
Disclosure of Invention
The invention aims to provide a method for preparing carbon nano tubes from coal. The mass and volume of the particles are expressed in parts. The invention adopts the following technical scheme.
A method for preparing carbon nanotubes from coal, comprising the steps of:
the first step: anthracite is selected, crushed and screened to obtain coal particles with the particle size of 0.1-10.0 nm;
and a second step of: mixing 50-80 parts of the coal particles obtained in the first step with 20-60 parts of the activating agent, placing the mixture into a high-temperature tube furnace, heating to 900-1050 ℃ at a heating rate of 3-5 ℃, stabilizing the temperature for 0.5-2h, and then controlling the space velocity to 8000-10000h -1 Introducing carbon dioxide to activate for 1-5h;
and a third step of: selecting 30-60 parts of activated coal particles obtained in the second step, and loading potassium bicarbonate on the activated coal particles to obtain a mixture, wherein the mass part ratio of the potassium bicarbonate to the activated coal particles is 1:1-3; placing the mixture into a first carbon nanotube preparation reactor, and controlling the space velocity to be 8000-30000h -1 The volume ratio of the inlet is 1:1, heating the mixed gas of methane and carbon monoxide to 850-950 ℃ at a speed of 3-5 ℃/min, and keeping the temperature for 3-5 hours to realize the nucleation and growth of the carbon nano tube, thus preparing the coal-based carbon nano tube A containing carbon black, carbon deposit and other impurities;
fourth step: placing the coal-based carbon nanotube A obtained in the third step into a second carbon nanotube preparation reactor with the temperature stabilized at 800-950 ℃ and the gas volume space velocity of 8000-20000h -1 Introducing a mixed gas of methane and carbon dioxide, maintaining for 4-6 hours, performing methane carbon dioxide reforming reaction, purifying and preparing a carbon nano tube E, and obtaining a mixed gas product mainly comprising carbon monoxide and hydrogen;
fifth step: 30-50 parts of the coal-based carbon nano tube B obtained in the fourth step are placed into a supercritical fluid of carbon dioxide with the temperature of 31-34 ℃ and the pressure of 7.38-8.05MPa for maintaining the pressure for 1-3 hours, and carbon black, carbon deposit and part of residual tar in the coal-based carbon nano tube B are eliminated, so that purer coal-based carbon nano tube C is obtained;
sixth step: repeating the processes of the fourth step and the fifth step for 1-5 times to obtain coal-based carbon nanotubes D, then impregnating 20-40 parts of the coal-based carbon nanotubes D with 50-100 parts of hydrogen supply and antioxidant solvents according to the mass part ratio, and then washing with 20-60 parts of hydrochloric acid solution to obtain the coal-based carbon nanotubes E with the purity of more than or equal to 40%.
Preferably, the activation treatment is to add 50-80 parts of coal particles and 20-60 parts of activator mixture into a high-temperature tube furnace, heat up to 900-1050 ℃ at a heating rate of 3-5 ℃ and stabilize the temperature for 0.5-2h, and then cool down to 8000-10000h at a space velocity -1 Introducing carbon dioxide to activate for 1-5h; the activator is prepared from 5-20 parts of KOH and 5-10 parts of K 2 CO 3 And 90-120 parts of distilled water, and stirring until the mixture is completely dissolved.
Preferably, the carbon nano tube growth catalyst is potassium bicarbonate, and the mass ratio of the carbon nano tube growth catalyst to the activated coal particles is 1:1-3.
Preferably, the carbon nanotube growth catalyst supported activated coal particles are prepared by an isovolumetric impregnation method.
Preferably, in the third step, a mixed gas of methane and carbon monoxide with the gas volume ratio of 1:1 is introduced, and the gas space velocity is 8000-30000h -1 The method comprises the steps of carrying out a first treatment on the surface of the And (3) keeping the temperature of the mixture C in a carbon nanotube preparation reactor for 3-5 hours to obtain the coal-based carbon nanotube A.
Preferably, in step threeThe coal-based carbon nano tube A is stabilized in a carbon nano tube preparation reactor at the temperature of 800-950 ℃, and the airspeed of the mixed gas of carbon dioxide and methane is 8000-20000h -1 The volume ratio of methane to carbon dioxide in the mixed gas is 3:1-4, and the temperature is kept constant for 4-6h, so as to obtain the primarily purified carbon nano tube B.
Preferably, in the fifth step, the supercritical carbon dioxide fluid has a temperature of 31-34 ℃ and a pressure of 7.38-8.05MPa.
Preferably, in the seventh step, the hydrogen-supplying and antioxidant solvent is a mixture of ethanol and isopropanol, the mass ratio of the ethanol to the isopropanol is 1:0.2-0.6, and the concentration of the hydrochloric acid solution is 5% -20%.
Compared with the prior art, the invention has the beneficial effects that:
(1) The preparation process of the coal-base carbon nanotube includes converting anthracite into microporous activated coal particle, and the process includes KOH and K 2 CO 3 The two activators synergistically change the chemical composition of oxygen-containing functional groups and pore structures on the surface of coal, so that bonds between carbon atoms and heteroatoms in the molecules of the heterocyclic compounds of the coal are easy to split for polymerization or polycondensation reaction, and activated coal particles with rich micropore structures are obtained. The activated coal particles with rich micropore structures are used as raw materials for preparing the coal-based carbon nanotubes, are favorable for adsorption and dispersion of K ions serving as catalysts on the surfaces of micropores, and ensure uniform dispersion of the K ion catalysts. Meanwhile, the micromolecular volatile matters released in the catalytic process are beneficial to reducing the poisoning and carbon deposition generation of the catalyst, reducing the deposition of coal tar and carbon deposition impurities in the carbon nanotubes, and promoting the growth of more carbon nanotubes on the substrate of the micropore structure of the activated coal.
(2) In the method, the potassium bicarbonate catalyst is added as a hydroxyl corrosion inhibitor and provides an alkaline environment to promote the catalysis of K ions, and activated coal particles nucleate and grow under the action of the potassium bicarbonate catalyst and the high-temperature alkaline condition of a methane and carbon monoxide mixed gas atmosphere with a certain airspeed to generate the coal-based carbon nano tube containing carbon black, carbon deposit and other impurities. Then at CH 4 And CO 2 Under the atmosphere of mixed gasBy adjusting CH 4 And CO 2 The ratio of the two is used for dynamically adjusting the growth process of the coal-based carbon nano tube, so that the carbon nano tube grows directionally, and the carbon deposition and the carbon black can be further reduced.
(3) In the method, the supercritical CO with low temperature and high pressure is adopted 2 The system is used for treating the intermediate product of the coal-based carbon nano tube, and has the effects of eliminating carbon black, carbon deposit and partial residual tar in the coal-based carbon nano tube, and adding the porous intermediate product of the coal-based carbon nano tube to CO 2 Promote the continuous growth of the carbon nano tube, thereby increasing the yield and the purity of the product. Relative to CO-H 2 O、CO 2 -H 2 In the supercritical technologies such as O and the like, the temperature requirement of the supercritical process of carbon dioxide is low, the pressure condition at low temperature is better controlled, and impurities which affect the catalytic activity partially can be removed more efficiently.
(4) In the method, the obtained coal-based carbon nanotube is treated by the hydrogen-supplying solvent, so that oxygen-containing functional groups on the surface of the carbon nanotube can be reduced, the surface is smoother, the oxidation resistance of the carbon nanotube can be improved by the anti-oxidation solvent dipping treatment, and finally the oxygen-containing functional groups on the surface which are not completely separated in the treatment process can be eliminated by the hydrochloric acid treatment, so that a large number of carbon nanotube products with high purity and good oxidation resistance can be obtained.
Drawings
Fig. 1 is a flow chart of a process for preparing carbon nanotubes according to the present invention.
Fig. 2 is a SEM characterization of the carbon nanotubes prepared in example 1 of the present invention, from which it can be seen that this scheme produces a large number of carbon nanotubes and relatively orderly growth, overall smooth.
Detailed Description
For a more particular understanding of the technical content, features and effects of the present invention, the present invention will now be described in further detail with reference to the accompanying drawings and examples.
Example 1.
A method for preparing carbon nano tubes by coal, which is characterized by comprising the following steps: the method comprises the following steps:
the first step: anthracite is selected, crushed and screened to obtain coal particles with the particle size of 0.1-10.0 nm;
and a second step of: selecting 50 parts and 20 parts of activator (5 parts KOH and 5 parts K are used as activator) of the coal particles obtained in the step one 2 CO 3 Mixing with 90 parts of distilled water completely, placing into a beaker, uniformly stirring to dissolve completely, placing into a high-temperature tube furnace, heating to 900 deg.C at a heating rate of 3 deg.C, stabilizing temperature for 1 hr, and stirring at airspeed of 8000 hr -1 Introducing carbon dioxide to activate for 2 hours;
and a third step of: selecting 30 parts of activated coal particles obtained in the second step, and loading potassium bicarbonate on the activated coal particles to obtain a mixture, wherein the mass part ratio of the potassium bicarbonate to the activated coal particles is 1:1; placing the mixture into a first carbon nanotube preparation reactor, and controlling the space velocity to be 8000h -1 The volume ratio of the inlet is 1:1, heating the mixed gas of methane and carbon monoxide to 850 ℃ at a speed of 3 ℃/min, and keeping the temperature for 3 hours at the temperature to realize the nucleation and growth of the carbon nano tube, so as to prepare the coal-based carbon nano tube A containing carbon black, carbon deposit and other impurities;
fourth step: placing the coal-based carbon nanotube A obtained in the third step into a second carbon nanotube preparation reactor with the internal temperature of 800 ℃ and the gas volume space velocity of 8000h -1 Introducing mixed gas with the volume ratio of methane to carbon dioxide of 3:1, maintaining for 4 hours, performing methane carbon dioxide reforming reaction, purifying and preparing a carbon nano tube E, and obtaining a mixed gas product mainly comprising carbon monoxide and hydrogen;
fifth step: 30 parts of the coal-based carbon nanotube B obtained in the fourth step are placed into a carbon dioxide supercritical fluid with the temperature of 31 ℃ and the pressure of 7.38MPa for maintaining the pressure for 1h, and carbon black, carbon deposit and part of residual tar in the coal-based carbon nanotube B are eliminated, so that a purer coal-based carbon nanotube C is obtained;
sixth step: repeating the steps four and five for 1-5 times to obtain coal-based carbon nanotubes D, impregnating 20 parts of the coal-based carbon nanotubes D with 50 parts of a mixture of ethanol and isopropanol in a mass part ratio of 1:0.2, and washing with 20 parts of a hydrochloric acid solution with a concentration of 5%, so as to obtain the coal-based carbon nanotubes E with a purity of 41.5%.
Example 2.
A method for preparing carbon nano tubes by coal, which is characterized by comprising the following steps: the method comprises the following steps:
the first step: anthracite is selected, crushed and screened to obtain coal particles with the particle size of 0.1-10.0 nm;
and a second step of: selecting 60 parts and 40 parts of activator (the activator is prepared from 10 parts of KOH and 8 parts of K) 2 CO 3 Mixing with 100 parts of distilled water completely, placing into a beaker, uniformly stirring to dissolve completely, placing into a high-temperature tube furnace, heating to 1000deg.C at a heating rate of 4deg.C, stabilizing temperature for 1 hr, and controlling space velocity to 9000 hr -1 Introducing carbon dioxide to activate for 3 hours;
and a third step of: selecting 40 parts of activated coal particles obtained in the second step, and loading potassium bicarbonate on the activated coal particles to obtain a mixture, wherein the mass part ratio of the potassium bicarbonate to the activated coal particles is 1:2; placing the mixture into a first carbon nanotube preparation reactor with space velocity of 10000h -1 The volume ratio of the inlet is 1:1, heating the mixed gas of methane and carbon monoxide to 900 ℃ at a speed of 4 ℃/min, and keeping the temperature for 4 hours at the temperature to realize the nucleation and growth of the carbon nano tube, thus preparing the coal-based carbon nano tube A containing carbon black, carbon deposit and other impurities;
fourth step: placing the coal-based carbon nanotube A obtained in the third step into a second carbon nanotube preparation reactor with the internal temperature of 900 ℃ and the gas volume space velocity of 10000h -1 Introducing mixed gas with the volume ratio of methane to carbon dioxide of 3:2, maintaining for 5 hours, performing methane carbon dioxide reforming reaction, purifying and preparing a carbon nano tube E, and obtaining a mixed gas product mainly comprising carbon monoxide and hydrogen;
fifth step: placing 40 parts of the coal-based carbon nanotube B obtained in the fourth step into a carbon dioxide supercritical fluid with the temperature of 32 ℃ and the pressure of 7.60MPa for maintaining the pressure for 2 hours, and eliminating carbon black, carbon deposit and part of residual tar in the coal-based carbon nanotube B to obtain a purer coal-based carbon nanotube C;
sixth step: repeating the fourth step and the fifth step for 1-5 times to obtain a coal-based carbon nanotube D, then impregnating 30 parts of the coal-based carbon nanotube D with 80 parts of a mixture of ethanol and isopropanol in a mass part ratio of 1:0.4, and then washing with 40 parts of a hydrochloric acid solution with the concentration of 10%, thereby finally obtaining the coal-based carbon nanotube E with the purity of 45.5%.
Example 3.
A method for preparing carbon nano tubes by coal, which is characterized by comprising the following steps: the method comprises the following steps:
the first step: anthracite is selected, crushed and screened to obtain coal particles with the particle size of 0.1-10.0 nm;
and a second step of: selecting 80 parts and 60 parts of activator (20 parts KOH and 10 parts K are used as activator) of the coal particles obtained in the step one 2 CO 3 Mixing with 120 parts of distilled water completely, placing into a beaker, uniformly stirring to dissolve completely, placing into a high-temperature tube furnace, heating to 1050 deg.C at a heating rate of 5 deg.C, stabilizing temperature for 2 hr, and stirring at space velocity of 10000 hr -1 Introducing carbon dioxide to activate for 5 hours;
and a third step of: selecting 60 parts of activated coal particles obtained in the second step, and loading potassium bicarbonate on the activated coal particles to obtain a mixture, wherein the mass part ratio of the potassium bicarbonate to the activated coal particles is 1:3; placing the mixture into a first carbon nanotube preparation reactor with a space velocity of 30000h -1 The volume ratio of the inlet is 1:1, heating the mixed gas of methane and carbon monoxide to 950 ℃ at a speed of 5 ℃/min, and keeping the temperature for 5 hours at the temperature to realize the nucleation and growth of the carbon nano tube, so as to prepare the coal-based carbon nano tube A containing carbon black, carbon deposit and other impurities;
fourth step: placing the coal-based carbon nanotube A obtained in the third step in a second carbon nanotube preparation reactor with the internal temperature of 950 ℃ to be stabilized in the carbon nanotube preparation reactor at the temperature of 950 ℃, and using the gas volume space velocity of 20000h -1 Introducing mixed gas with the volume ratio of methane to carbon dioxide of 3:4, maintaining for 6 hours, performing methane carbon dioxide reforming reaction, purifying and preparing a carbon nano tube E, and obtaining a mixed gas product mainly comprising carbon monoxide and hydrogen;
fifth step: placing 50 parts of the coal-based carbon nanotube B obtained in the fourth step into a carbon dioxide supercritical fluid with the temperature of 34 ℃ and the pressure of 8.05MPa for pressure maintaining for 3 hours, and eliminating carbon black, carbon deposit and part of residual tar in the coal-based carbon nanotube B to obtain a purer coal-based carbon nanotube C;
sixth step: repeating the steps four and five for 1-5 times to obtain coal-based carbon nanotubes D, impregnating 40 parts of the coal-based carbon nanotubes D with 100 parts of ethanol and isopropanol mixture with the mass part ratio of 1:0.6, and washing with 60 parts of hydrochloric acid solution with the concentration of 20%, so as to obtain the coal-based carbon nanotubes E with the purity of 48%.
Claims (10)
1. A method for preparing high-purity carbon nanotubes by coal is characterized in that: the method comprises the following steps:
the first step: crushing and screening an anthracite sample to obtain coal particles with the particle size of 0.1-10.0 nm;
and a second step of: adding 20-60 parts of activating agent into 50-80 parts of the coal particles obtained in the first step for activating treatment, and cooling to room temperature under the nitrogen condition after activation to obtain activated coal particles;
and a third step of: selecting 30-60 parts of activated coal particles obtained in the second step, and loading a carbon nano tube growth catalyst on the activated coal particles to obtain a mixture; putting the mixture into a first carbon nanotube preparation reactor, introducing methane and carbon monoxide mixed gas with a certain space velocity, heating to 850-950 ℃ at a heating rate of 3-5 ℃/min, and maintaining the temperature for a period of time to realize the nucleation and growth of the carbon nanotubes, so as to obtain the coal-based carbon nanotubes A containing impurities;
fourth step: placing the coal-based carbon nanotube A obtained in the third step into a second carbon nanotube preparation reactor with the internal temperature of 800-950 ℃, introducing carbon dioxide and methane mixed gas, and keeping for a period of time to obtain a primarily purified coal-based carbon nanotube B and a mixed gas product mainly comprising carbon monoxide and hydrogen;
fifth step: transferring 30-50 parts of the primarily purified coal-based carbon nanotubes B obtained in the fourth step into a carbon dioxide supercritical fluid, and maintaining the pressure for 1-3 hours to eliminate carbon deposition and residual tar in the coal-based carbon nanotubes B and obtain pure coal-based carbon nanotubes C;
sixth step: repeating the steps four and five for 1-5 times to obtain coal-based carbon nanotubes D, then impregnating 20-40 parts of the coal-based carbon nanotubes D with 50-100 parts of hydrogen supply and antioxidant solvents according to the mass part ratio, and then washing with 20-60 parts of hydrochloric acid solution to obtain the coal-based carbon nanotubes E with the purity of more than or equal to 40%.
2. The method for preparing high purity carbon nanotubes from coal according to claim 1, wherein: the activation treatment in the second step is to add 50-80 parts of coal particles and 20-60 parts of activator mixture into a high-temperature tube furnace, raise the temperature to 900-1050 ℃ at a temperature raising rate of 3-5 ℃ and stabilize the temperature for 0.5-2h, and then make the air velocity be 8000-10000h -1 Introducing carbon dioxide to activate for 1-5h.
3. The method for preparing high purity carbon nanotubes from coal according to claim 2, wherein: the activator is prepared from 5-20 parts of KOH and 5-10 parts of K 2 CO 3 And 90-120 parts of distilled water, and stirring until the mixture is completely dissolved.
4. The method for preparing high purity carbon nanotubes from coal according to claim 1, wherein: the carbon nano tube growth catalyst in the third step is potassium bicarbonate, and the mass part ratio of the carbon nano tube growth catalyst to the activated coal particles is 1:1-3.
5. The method for preparing high purity carbon nanotubes from coal according to claim 1, wherein: in the third step, the activated coal particles loaded with the carbon nano tube growth catalyst are subjected to an isovolumetric impregnation method.
6. The method for preparing high purity carbon nanotubes from coal according to claim 1, wherein: step three, introducing mixed gas of methane and carbon monoxide with the gas volume ratio of 1:1, and the gas airspeed of 8000-30000h -1 The method comprises the steps of carrying out a first treatment on the surface of the And (3) keeping the temperature of the mixture C in a carbon nanotube preparation reactor for 3-5 hours to obtain the coal-based carbon nanotube A.
7. The method for preparing high purity carbon nanotubes from coal according to claim 1, wherein: in the fourth step, the coal-based carbon nanotube A obtained in the third step is stabilized in a carbon nanotube preparation reactor at 800-950 ℃, and the airspeed of the mixed gas of carbon dioxide and methane is 8000-20000h -1 The volume ratio of methane to carbon dioxide in the mixed gas is 3:1-4, and the temperature is kept constant for 4-6h, so as to obtain the primarily purified carbon nano tube B.
8. The method for preparing high purity carbon nanotubes from coal according to claim 1, wherein: in the fifth step, the supercritical carbon dioxide temperature is 31-34 ℃ and the pressure is 7.38-8.05MPa.
9. The method for preparing high purity carbon nanotubes from coal according to claim 1, wherein: in the sixth step, the hydrogen supply and antioxidation solvent is a mixture of ethanol and isopropanol, and the mass ratio of the ethanol to the isopropanol is 1:0.2-0.6.
10. The method for preparing high purity carbon nanotubes from coal according to claim 1, wherein: in the sixth step, the concentration of the hydrochloric acid solution is 5% -20%.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20100082707A (en) * | 2009-01-09 | 2010-07-19 | 세종대학교산학협력단 | Method for purifying carbon nanotubes and method for dispersing carbon nanotubes |
| CN110562960A (en) * | 2019-09-05 | 2019-12-13 | 太原理工大学 | preparation and purification method of coal-based carbon nano tube |
| CN111333029A (en) * | 2020-02-29 | 2020-06-26 | 太原理工大学 | Process for reforming and reducing iron and generating carbon nano tube by methane and carbon dioxide |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20100082707A (en) * | 2009-01-09 | 2010-07-19 | 세종대학교산학협력단 | Method for purifying carbon nanotubes and method for dispersing carbon nanotubes |
| CN110562960A (en) * | 2019-09-05 | 2019-12-13 | 太原理工大学 | preparation and purification method of coal-based carbon nano tube |
| CN111333029A (en) * | 2020-02-29 | 2020-06-26 | 太原理工大学 | Process for reforming and reducing iron and generating carbon nano tube by methane and carbon dioxide |
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