CN115818625A - Method for modifying multi-walled carbon nanotube by oxidation - Google Patents
Method for modifying multi-walled carbon nanotube by oxidation Download PDFInfo
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
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Abstract
The invention belongs to the technical field of nano materials, and particularly relates to a method for modifying a multi-walled carbon nanotube by oxidation. Supercritical water is used as an oxidant for reaction, so that the safety and environmental protection performance of the reaction process are improved, and the generation of pollution-free gas also greatly ensures the health of operators. The invention uses the hydrothermal kettle as a reaction vessel, and can uniformly heat the whole reaction system. The technical scheme has the advantages of better maintenance of the integrity of the carbon tube, larger particles of the carbon tube product after the reaction is finished, greatly shortened filtration process and greatly improved efficiency. The invention uses mild and environment-friendly oxidant to modify the carbon tube, and the yield is greatly improved.
Description
Technical Field
The invention belongs to the technical field of nano materials, and particularly relates to a method for performing oxidation modification on a carbon tube by using supercritical water.
Background
Since the discovery of carbon nanotubes by japanese scientist Iijima in 1991, special tubular hollow structures are one of the most potential carbon materials due to their excellent electrical conductivity, thermal conductivity, large specific surface area, high mechanical properties. The unique properties of carbon tubes make them ideal framework or precursor materials for the preparation of composites. Nevertheless, the intrinsic characteristics of carbon tubes also cause problems for their application, such as the large aspect ratio making them highly susceptible to entanglement under van der waals forces, which results in dispersions of carbon tubes that are very unstable and highly susceptible to precipitation, while the surface of the carbon tubes is chemically inert, which to some extent hinders the rapid complexation and interaction of carbon tubes with other materials.
In order to solve the above problems, surface modification of carbon nanotubes is required, and the current modification methods are mainly physical and chemical modification. Chemical modification is usually carried out by adopting various strong oxidizers to carry out oxidation treatment on the surface of the carbon tube, wherein the most common and effective method is to use a mixed solution of concentrated nitric acid and concentrated sulfuric acid as the oxidizer. However, this method produces a large amount of NO as a polluting gas X The environment is damaged, and the danger to operators is also high. Secondly, the mixed acid solution has too strong oxidability, which causes serious damage to the structure of the carbon tube in the modification process and loses the excellent characteristics of a plurality of carbon tubes, so the final yield is low, and the method is not suitable for industrial production. Physical modification methods use surfactants, such as hydrophilic macromolecules or biological macromolecules, to treat carbon tubes. The method can maintain the integrity of the carbon tube to the maximum extent, but has the biggest defects that the modifiers are difficult to remove, the modified carbon tube and other materials have weak chemical interaction, cannot be effectively combined, and cannot exert the excellent performance of the carbon tube in the final composite material.
Disclosure of Invention
Aiming at the problems in the prior art, the invention designs a method for oxidizing and modifying a carbon tube by using supercritical water. The invention uses supercritical water to oxidize and modify the multi-walled carbon nano-tube, the supercritical water can promote the cracking of C-C bonds in the carbon tube, and the supercritical water not only can be used as a reactant, but also can be used as a catalyst to weaken the C-C bonds of an aromatic ring, thereby promoting the ring-opening reaction of a benzene ring on the carbon tube. The technology for modifying the carbon tube by supercritical water oxidation has the characteristics of high reaction efficiency, greenness, no pollution, high product yield and the like.
The technical scheme of the invention comprises the following operation steps:
wherein the raw material is a multi-walled carbon nanotube; deionized water.
Step one, weighing a certain amount of materials, ultrapure water and carbon tubes in a batching chamber by using an electronic balance, pouring the materials, the ultrapure water and the carbon tubes into a dry and clean middle kettle type reactor, and uniformly mixing.
And step two, checking the states of a water source, a power supply and a gas source of the reaction system, and ensuring that the reaction kettle system has good drainage and exhaust states and good laboratory ventilation.
And step three, connecting the reaction kettle with a temperature sensor device and ensuring good air tightness. Opening an Ar gas source for emptying, and closing a gas inlet valve after the air in the reaction kettle is completely exhausted; closing the pipeline for introducing Ar, slowly opening a gas release valve, and deflating to a set initial pressure; and closing the gas release valve, and increasing the pressure of a gas source for leak detection. If the variation range of the atmospheric pressure in 1.5 minutes is less than 0.01 MPa, the airtightness of the reaction system is considered to be good.
And step four, heating the reactor by using an electric heating furnace to enable the reaction system to reach reaction conditions. During the heating process, the leakage condition of the equipment is checked at any time by observing the change of temperature and pressure.
And step five, heating to a stable reaction temperature, closing the electric heating furnace after a preset retention time, taking the reaction kettle out of the furnace, naturally cooling the air, adding cooling water for water cooling when the temperature in the kettle is reduced to 250 ℃, and taking out the reaction kettle for air cooling.
And step six, collecting the treated carbon tube product through the steps of filtering, centrifuging, drying and the like after the reaction is finished.
And seventhly, cleaning the reaction kettle in a water tank, placing the reaction kettle in an ultrasonic cleaner for 20 minutes, and then placing the reaction kettle in a far infrared drying furnace for drying for about 1 hour to remove water in the reaction kettle, wherein the temperature is set to be 100 ℃.
Further, the amount of the carbon tubes and the deionized water in the step 1 can be adjusted within a certain range.
Further, the reaction time in the step 4 may be appropriately prolonged or shortened (5 to 30 minutes), depending on the scale of the reaction.
Further, the reaction temperature in the step 4 may be suitably increased or decreased (350 to 650 ℃), depending on the scale of the reaction.
Further, the reaction pressure in step 4 may be suitably increased or decreased (20 to 35 MPa), depending on the scale of the reaction.
The invention aims to provide a novel method for modifying a carbon tube, which can well stably suspend in aqueous solution at a certain concentration, and the method can obtain a composite material with excellent performance, wherein the surface of the carbon tube contains abundant surface functional groups, and the composite material can effectively interact with other materials.
In combination with the technical solutions and the technical problems to be solved, please analyze the advantages and positive effects of the technical solutions to be protected in the present invention from the following aspects:
first, aiming at the technical problems existing in the prior art and the difficulty in solving the problems, the technical problems to be solved by the technical scheme of the present invention are closely combined with results, data and the like in the research and development process, and some creative technical effects are brought after the problems are solved. The specific description is as follows:
compared with the prior art, the method for oxidizing and modifying the carbon tube by using the supercritical water has the following advantages:
(1) Supercritical water is used as an oxidant for reaction, so that the safety and environmental friendliness of the reaction process are improved, and the generation of pollution-free gas also greatly ensures the health of operators.
(2) The invention uses the hydrothermal kettle as a reaction container, and can uniformly heat the whole reaction system.
(3) Because the oxidability of the mixture of concentrated sulfuric acid and concentrated nitric acid is too strong, although the surface of the carbon tube is decorated with a large number of oxygen-containing groups after the reaction is finished, the carbon tube is also broken in the reaction process, and the excellent conductivity of the carbon tube is greatly weakened. The above-mentioned problems also present great difficulties in the work-up (filtration, grinding and collection) of the product. In contrast, the invention can maintain the integrity of the carbon tube well, the carbon tube product has larger particles after the reaction is finished, the filtering process is greatly shortened, and the efficiency is greatly improved.
(4) The invention uses the mild and environment-friendly oxidant to modify the carbon tube, and the yield is greatly improved. The yield of the traditional method is generally between 30 and 60 percent, and the yield of the method of the invention is as high as more than 85 percent.
(5) The invention provides a novel method for modifying a carbon tube, which can well stably suspend in aqueous solution at a certain concentration. In the technical scheme, the carbon tube obtained by the method contains abundant surface functional groups on the surface, can effectively interact with other materials, and can be used for preparing a composite material with excellent performance.
(6) The invention uses water in a supercritical state as a reactant, has low price, greatly reduces the cost of the carbon tube modification process, and is beneficial to expanded production.
Secondly, considering the technical scheme as a whole or from the perspective of products, the technical effect and advantages of the technical scheme to be protected by the invention are specifically described as follows:
the carbon tube treated by the method provided by the invention can be better dissolved in water to prepare stable carbon tube aqueous suspension;
the carbon tube obtained by the method has rich oxygen-containing functional groups on the surface, and can enhance the interaction with other carbon tubes;
the carbon tube subjected to oxidation modification can be effectively compounded with polymer monomers (pyrrole, aniline, thiophene and the like) to be processed into an electrode material of the supercapacitor with more optimized performance.
The carbon tube and the composite material of the polymer (polypyrrole, polyaniline, polythiophene and the like) thereof obtained by the invention have better thermal stability.
The carbon tube prepared by the invention can be used as a high-conductivity binder of a 3D printing energy material, has higher conductivity, simultaneously retains the tubular structure of the carbon tube, and can be better crosslinked and coated with an active material.
The carbon tube prepared by the invention can be used as a conductive additive in an electrode material for preparing a lithium metal battery, can improve the conductivity of the electrode, reduces the electron transmission resistance, and can be effectively dispersed in a corresponding solvent.
The carbon tube prepared by the invention can be used as a photocatalyst in the field of photocatalysis to degrade organic pollutants.
Third, as an inventive supplementary proof of the claims of the present invention, there are also presented several important aspects:
(1) The expected income and commercial value after the technical scheme of the invention is converted are as follows:
the main raw material used in the technical scheme of the invention is water, which is green and environment-friendly and has low cost; the reactor is used as a hydrothermal reaction kettle, and the use is mature in the industry. Therefore, the invention is a planned carbon tube oxidation modification technology with great commercial prospect.
(2) The technical scheme of the invention solves the technical problem that people are eagerly to solve but can not be successfully solved all the time:
carbon tubes are two-dimensional tubular materials with excellent performance, but the application of the carbon tubes is always subject to the technical bottlenecks of easy agglomeration, difficult surface modification and the like in aqueous solution. Although the traditional mixed acid modification method is effective, the experimental danger and the hazard are large, the cost is high, and the industrial production is difficult all the time. The supercritical water oxidation modification technology provided by the invention has the advantages of environmental friendliness, high efficiency, small investment, rapidness and the like, and is expected to overcome the technical problem of application of the carbon nanotubes.
Drawings
Fig. 1 is a flow chart of a novel method for modifying a carbon tube according to an embodiment of the present invention.
FIG. 2 is a graph showing the results of thermogravimetric analysis of carbon tubes in the conventional method and the method of the present invention according to the example of the present invention.
FIG. 3 is a graph showing the results of cyclic voltammetry curves of carbon tube/polyaniline composites treated by the conventional method and the method of the present invention;
fig. 4 shows that the carbon tube obtained by the novel method for modifying a carbon tube according to the embodiment of the present invention also exhibits higher capacitance after being composited with aniline.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.
The embodiment of the invention provides a method for carrying out oxidation modification on a carbon tube by using supercritical water. The supercritical fluid is a fluid having a temperature and a pressure higher than a critical pressure. The fluid has the advantages of both liquid and gas, the viscosity of the supercritical fluid is small, the diffusion coefficient is large, the density is high, the supercritical fluid has good dissolution characteristics and mass transfer characteristics, and the characteristics of the fluid near the critical point are very sensitive to the change of force and temperature. Supercritical fluids, which are neither gaseous nor liquid substances, but single phase substances. It has some of the properties of both a gaseous substance and a liquid substance. Supercritical fluids are not only a good separation medium, but also a good reaction medium. The method is green and efficient, has simple process, can carry out effective oxidation modification on the surface of the carbon tube, improves the dispersibility of the carbon tube in water, has small damage to the carbon tube, and can effectively combine the carbon tube with other materials by the oxidation functional group contained on the surface of the modified carbon tube. Therefore, supercritical water carbon dioxide tube is a feasible strategy for improving the applicability of carbon tube in the future.
This section is an explanatory embodiment expanding on the claims so as to fully understand how the present invention is embodied by those skilled in the art.
As shown in fig. 1, the embodiment of the present invention provides a novel method for modifying carbon tubes, which can be well and stably suspended in an aqueous solution at a certain concentration:
wherein the raw material is a multi-walled carbon nanotube; deionized water.
Step one, weighing a certain amount of materials, ultrapure water and carbon tubes in a batching chamber by using an electronic balance, pouring the materials, the ultrapure water and the carbon tubes into a dry and clean middle kettle type reactor, and uniformly mixing (the mass ratio of the carbon tubes to the ultrapure water is 5-25 wt.%).
And step two, checking the states of a water source, a power supply and a gas source of the reaction system to ensure that the reaction kettle system has good drainage and exhaust states and good ventilation of a laboratory.
And step three, connecting the reaction kettle with a temperature sensor device and ensuring good air tightness. Opening an Ar gas source for emptying, and closing a gas inlet valve after the air in the reaction kettle is completely exhausted; closing the pipeline for introducing Ar, slowly opening a gas release valve, and deflating to a set initial pressure; and closing the gas release valve, and increasing the pressure of a gas source for leak detection. If the variation range of the atmospheric pressure in 1.5 minutes is less than 0.01 MPa, the airtightness of the reaction system is considered to be good.
And step four, heating the reactor by using an electric heating furnace to enable the reaction system to reach the reaction condition, wherein the reaction time is 5-30 minutes, the reaction temperature is 350-650 ℃, and the reaction pressure is 20-35 MPa. During the heating process, the leakage condition of the equipment is checked at any time by observing the change of temperature and pressure.
And step five, heating to a stable reaction temperature, closing the electric heating furnace after a preset retention time, taking the reaction kettle out of the furnace, naturally cooling the air, cooling the reaction kettle by cooling water after the temperature in the reaction kettle is reduced to 250 ℃, and taking out the reaction kettle for air cooling.
And step six, collecting the treated carbon tube product through the steps of filtering, centrifuging, drying and the like after the reaction is finished.
And seventhly, cleaning the reaction kettle in a water tank, placing the reaction kettle in an ultrasonic cleaner for 20 minutes, and then placing the reaction kettle in a far infrared drying furnace for drying for about 1 hour to remove water in the reaction kettle, wherein the temperature is set to be 100 ℃.
The present invention will be described in further detail with reference to specific examples.
Example 1
The technical scheme of the invention comprises the following operation steps:
wherein the raw material is a multi-walled carbon nanotube; deionized water.
Step one, 400 milligrams of carbon tubes and 20 milliliters of deionized water are weighed in a batching room by using an electronic balance to prepare a solution with the material concentration of 10 percent, and the solution is poured into a dry and clean middle kettle type reactor to be uniformly mixed.
And step two, checking the states of a water source, a power supply and a gas source of the reaction system, and ensuring that the reaction kettle system has good drainage and exhaust states and good laboratory ventilation.
And step three, connecting the reaction kettle with a temperature sensor device and ensuring good air tightness. Opening an Ar gas source for emptying, and closing a gas inlet valve after the air in the reaction kettle is completely exhausted; closing the pipeline for introducing Ar, slowly opening a gas release valve, and deflating to the set initial pressure; and closing the gas release valve, and increasing the pressure of a gas source for leak detection. If the variation range of the atmospheric pressure in 1.5 minutes is less than 0.01 MPa, the airtightness of the reaction system is considered to be good.
And step four, heating the reactor by using an electric heating furnace to enable the reaction system to reach the reaction condition. The supercritical water reaction temperature is set to be 500 ℃, the reaction pressure is set to be 30 MPa, and the reaction time is set to be 20 minutes. During the heating process, the leakage condition of the equipment is checked at any time by observing the change of temperature and pressure.
And step five, heating to a stable reaction temperature, closing the electric heating furnace after a preset retention time, taking the reaction kettle out of the furnace, naturally cooling the air, cooling the reaction kettle by cooling water after the temperature in the reaction kettle is reduced to 250 ℃, and taking out the reaction kettle for air cooling.
And step six, collecting the treated carbon tube product through the steps of filtering, centrifuging, drying and the like after the reaction is finished.
And seventhly, cleaning the reaction kettle in a water tank, placing the reaction kettle in an ultrasonic cleaner for 20 minutes, and then placing the reaction kettle in a far infrared drying furnace for drying for about 1 hour to remove water in the reaction kettle, wherein the temperature is set to be 100 ℃.
Further, in step 1, the carbon tube is 200 mg, the deionized water is 20 ml, and the material concentration is 10%.
Further, the reaction time of the step 4 is 20 minutes.
Further, the reaction temperature of the step 4 is 500 ℃.
Further, the step 4 reaction pressure is 25 mpa.
Example 2
The technical scheme of the invention comprises the following operation steps:
wherein the raw material is a multi-walled carbon nanotube; deionized water.
Step one, 150 mg of carbon tubes and 15 ml of deionized water are weighed in a batching room by using an electronic balance to prepare a solution with the material concentration of 10%, and the solution is poured into a dry and clean middle kettle type reactor to be uniformly mixed.
And step two, checking the states of a water source, a power supply and a gas source of the reaction system, and ensuring that the reaction kettle system has good drainage and exhaust states and good laboratory ventilation.
And step three, connecting the reaction kettle with a temperature sensor device and ensuring good air tightness. Opening an Ar gas source for emptying, and closing a gas inlet valve after the air in the reaction kettle is completely exhausted; closing the pipeline for introducing Ar, slowly opening a gas release valve, and deflating to the set initial pressure; and closing the gas release valve, and increasing the pressure of a gas source for leak detection. If the variation range of the atmospheric pressure in 1.5 minutes is less than 0.01 MPa, the airtightness of the reaction system is considered to be good.
And step four, heating the reactor by using an electric heating furnace to enable the reaction system to reach reaction conditions. The supercritical water reaction temperature is set to be 400 ℃, the reaction pressure is set to be 20 MPa, and the reaction time is set to be 15 minutes. During the heating process, the leakage condition of the equipment is checked at any time by observing the change of temperature and pressure.
And step five, heating to a stable reaction temperature, closing the electric heating furnace after a preset retention time, taking the reaction kettle out of the furnace, naturally cooling the air, adding cooling water for water cooling when the temperature in the kettle is reduced to 250 ℃, and taking out the reaction kettle for air cooling.
And step six, collecting the treated carbon tube product through the steps of filtering, centrifuging, drying and the like after the reaction is finished.
And seventhly, cleaning the reaction kettle in a water tank, placing the reaction kettle in an ultrasonic cleaner for 20 minutes, and then placing the reaction kettle in a far infrared drying furnace for drying for about 1 hour to remove water in the reaction kettle, wherein the temperature is set to be 100 ℃.
Further, in step 1, the carbon tube is 200 mg, the deionized water is 20 ml, and the material concentration is 10%.
Further, the reaction time of the step 4 is 20 minutes.
Further, the reaction temperature of the step 4 is 500 ℃.
Further, the step 4 reaction pressure is 25 mpa.
Comparative example 1:
untreated pristine carbon nanotubes.
Comparative example 2:
carbon tubes treated with concentrated nitric acid and concentrated sulfuric acid were used.
In order to prove the creativity and the technical value of the technical scheme of the invention, the part is the application example of the technical scheme of the claims on specific products or related technologies.
In the technical scheme, the carbon tube obtained by the method contains abundant surface functional groups on the surface, can effectively interact with polyaniline, polypyrrole, polythiophene and other conductive polymers, and can be used for preparing a composite material with excellent performance. The specific operation is as follows: 150 mg of carbon tubes and 15 ml of deionized water are weighed in a batching room by using an electronic balance to prepare a solution with the material concentration of 10 percent, and the solution is poured into a dry and clean middle kettle type reactor to be uniformly mixed. The reaction kettle is connected with a temperature sensor device, the air tightness is ensured to be good, the reaction temperature of supercritical water is set to be 400 ℃, the reaction pressure is set to be 20 MPa, and the reaction time is set to be 15 minutes. After the preset retention time, the electric heating furnace is closed, the reaction kettle is taken out of the furnace, natural air cooling is carried out, cooling water is put into the reaction kettle for water cooling when the temperature in the reaction kettle is reduced to 250 ℃, and then the reaction kettle is taken out for air cooling. And pouring out the reaction materials in the reaction kettle, and obtaining the carbon tube after oxidation modification through suction filtration, centrifugation and drying. The above steps were repeated three times to obtain 500 mg of modified carbon tubes, which were placed in 500 ml of solution for ultrasonic dispersion. Subsequently, 12 ml of aniline monomer was added to the above mixture and stirred. Then, 30 g of ammonium persulfate was dissolved in 100 ml of a 4 mol/l hydrochloric acid solution, and then added to the mixture of the carbon tubes and the aniline monomer. And (3) completing the polymerization reaction after 24 hours under the ice-bath condition, and finally obtaining the polyaniline-carbon tube composite material through filtration. The embodiment of the invention achieves some positive effects in the process of research and development or use, and has great advantages compared with the prior art, and the following contents are described by combining data, diagrams and the like in the test process.
As shown in fig. 2 and 3, the embodiment of the present invention provides a novel method for modifying a carbon tube. The carbon tube prepared by the invention and the carbon tube prepared by the traditional method have greatly improved thermal stability and structural integrity compared with the carbon tube treated by the traditional method.
The behavior of the carbon tube obtained by the treatment method of the invention is almost the same as that of the original carbon tube in thermogravimetric analysis, and the decomposition temperature of the carbon tube treated by the traditional method is obviously reduced, which shows that the method of the invention better keeps the original structure of the carbon tube and the corresponding excellent performance thereof.
As shown in fig. 4, polyaniline in the polymer composite synthesized by the method of the present invention can also be coated on the surface of the carbon tube after treatment, and the final product has high porosity and specific surface area. In cyclic voltammograms, the energy stored is proportional to the size of the cyclic voltammogram. The carbon tube obtained by the method is compounded with aniline, and then shows higher capacitance of 238.9 Farad/g, while the capacitance value of the carbon tube modified by the traditional method and the polyaniline composite material is 140.02 Farad/g. The precursor of the carbon tube modified by the method of the invention fully exerts the outstanding conductivity of the carbon tube when being used as a polymer composite material, and the electrochemical performance of the final composite material is superior to that of the carbon tube polyaniline composite material modified by the traditional method.
The method for modifying the carbon tube has the characteristics of simplicity, high efficiency, environmental protection, safety, high yield, easiness in amplification and the like, and the treated carbon tube also shows better energy storage performance in the application of the composite material precursor.
The carbon tube treated by the method of the invention can be used as a precursor of a polymer composite material, so that the excellent conductivity of the carbon tube is fully exerted, and the electrochemical performance of the final composite material is superior to that of the carbon tube polypyrrole composite material treated by the traditional method.
The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.
Claims (8)
1. A method for oxidizing and modifying multi-walled carbon nanotubes, which is characterized in that supercritical water is used for oxidizing and modifying the multi-walled carbon nanotubes.
2. The method for the oxidative modification of multi-walled carbon nanotubes as claimed in claim 1, comprising the following steps:
step one, weighing a certain amount of materials, ultrapure water and carbon tubes in a batching chamber by using an electronic balance, pouring the materials into a dry and clean middle kettle type reactor, and uniformly mixing (the carbon tubes: the ultrapure water = 5;
checking the states of a water source, a power supply and a gas source of the reaction system, and ensuring the drainage and exhaust states of the reaction kettle system and the ventilation of a laboratory;
step three, connecting the reaction kettle with a temperature sensor device and ensuring good air tightness;
heating the reactor by an electric heating furnace to enable the reaction system to reach reaction conditions;
step five, heating to the reaction temperature (350-650 ℃), stabilizing the pressure (20-35 MPa), closing the electric heating furnace after the preset retention time (5-3 minutes), taking the reaction kettle out of the furnace, naturally cooling the air, cooling the reaction kettle by adding cooling water when the temperature in the reaction kettle is reduced to 250 ℃, and taking out the reaction kettle for air cooling;
step six, collecting the processed carbon tube product through the steps of filtering, centrifuging, drying and the like after the reaction is finished;
and seventhly, cleaning the reaction kettle in a water tank, placing the reaction kettle in an ultrasonic cleaner for 20 minutes, and then placing the reaction kettle in a far infrared drying furnace for drying for about 1 hour to remove water in the reaction kettle, wherein the temperature is set to be 100 ℃.
3. The method for modifying multi-walled carbon nanotubes by supercritical water oxidation according to claim 2, wherein the step three further comprises:
opening an Ar gas source for emptying, and closing a gas inlet valve after the air in the reaction kettle is completely exhausted; closing the pipeline for introducing Ar, slowly opening a gas release valve, and deflating to a set initial pressure; and closing the gas release valve, and increasing the pressure of a gas source for leak detection. If the variation range of the gas pressure in 1.5 minutes is less than 0.01 MPa, the airtightness of the reaction system is considered to be good.
4. The method for modifying multi-walled carbon nanotubes by supercritical water oxidation in step 1 of claim 2, wherein the carbon tubes are 200 mg, the deionized water is 20 ml, and the concentration of the material is 10%.
5. The method for oxidizing and modifying multi-walled carbon nanotubes with supercritical water according to claim 2, wherein the reaction time is 20 minutes.
6. The method for modifying multi-walled carbon nanotubes by supercritical water oxidation of claim 2 wherein step 4 the reaction temperature is 500 ℃.
7. The method for modifying multi-walled carbon nanotubes by supercritical water oxidation as described in claim 2 wherein the reaction pressure of step 4 is 25 mpa.
8. The method for modifying multi-walled carbon nanotubes by supercritical water oxidation as claimed in claim 2 wherein the starting material is multi-walled carbon nanotubes.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050002850A1 (en) * | 1999-07-21 | 2005-01-06 | Hyperion Catalysis International, Inc. | Methods of oxidizing multiwalled carbon nanotubes |
| US20120234204A1 (en) * | 2011-03-17 | 2012-09-20 | Bayer Materialscience Ag | Vapor phase functionalization of carbon nanotubes |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050002850A1 (en) * | 1999-07-21 | 2005-01-06 | Hyperion Catalysis International, Inc. | Methods of oxidizing multiwalled carbon nanotubes |
| US20120234204A1 (en) * | 2011-03-17 | 2012-09-20 | Bayer Materialscience Ag | Vapor phase functionalization of carbon nanotubes |
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