KR101659745B1 - CNT structure for water treatment, preparing thereof and seperating film using the same - Google Patents

Abstract

The present invention relates to a carbon nanotube structure for water treatment, characterized in that vertically arranged carbon nanotubes are densified and amorphous carbon on the outer wall of the carbon nanotubes is removed through heat treatment to selectively pass pure water to the outer wall of the carbon nanotubes. And a separator for water treatment comprising the same.

Description

Technical Field [0001] The present invention relates to a carbon nanotube structure for water treatment, a method of manufacturing the same, and a water treatment membrane including the same.

The present invention relates to a carbon nanotube structure for water treatment, a method for producing the carbon nanotube structure, and a reverse osmosis membrane for water treatment comprising the carbon nanotube structure. More particularly, the present invention relates to a carbon nanotube structure for water treatment which removes impurities of water through carbon nanotubes, And to a water treatment membrane containing the same.

As global warming is worsening the water shortage, desalination technology, which is a technology to secure alternative water resources, is attracting attention.

Therefore, it is expected that the water treatment process using separation membranes, which is the core technology of next-generation waterworks business utilizing alternative sources such as seawater desalination and reuse, will lead the water industry.

On the other hand, although the desalination technology using a membrane has become popular recently, there are problems such as high energy consumption and membrane contamination, and development of a technique for solving the problem is gradually becoming a limit.

In order to overcome these limitations, some technologies have been introduced that combine other technologies with existing water treatment technologies. Particularly, the technology of separators using carbon nanotubes has recently become an issue.

Since the discovery of carbon nanotubes (CNTs) by Japanese researchers Kenji Hata and Sumio Iijima in 1991, they have been actively studied since 1991, and have been used for industrial applications such as electronic / information communication, environment / The application value is expected to be very high.

In addition, with regard to water treatment, the possibility of manufacturing a membrane for water treatment using carbon nanotubes has recently been highly evaluated, and it is expected that application fields such as desalination and the like will be wide with a high rate of permeability and a stable ion removal rate.

Although the Hinds group was first reported in 2004 for the study of CNT membrane technology, two years later, in 2006, the Holt group measured the permeability of fluids and gases in the membrane using carbon nanotubes with smaller diameter compared to the conventional PC (Polycarbonate) membrane As a result of this comparative analysis, it became known as a representative of CNT membrane research.

In addition, a vertical-oriented CNT film technique with a dramatic improvement in permeability of about 100 to 1000 times was reported in 2004 for the first time in the world. According to this, a multi-walled carbon nanotube (CNT) was produced by chemical vapor deposition (CVD) Walled Nanotube, MWNT) were grown and then the vertically aligned membranes were prepared.

However, since the MWNTs having a relatively large average diameter of 7.5 ± 2.5 nm were used as the vertically arranged membranes, there was a problem that the desalting capacity (ion removal rate) was low.

U.S. Patent No. 8038887 discloses a membrane having a substrate material between an array of carbon nanotubes vertically aligned with a fluid-receiving membrane and a carbon nanotube and having a pore size of about 2 nm or less And the substrate material is formed of ceramic, silicon nitride, or the like. However, the above patent discloses that carbon nanotubes are formed of ceramics, silicon nitride, and the like, and are not excellent in porosity control, so that the permeability and desalination performance are not excellent and it is difficult to prevent contamination.

Accordingly, it has been desired to develop a separation membrane capable of preventing or minimizing the occurrence of contamination such as microbial adhesion, which is excellent in desalination performance during water treatment such as treatment of fresh water using carbon nanotubes.

In order to solve the above problems, it is an object of the present invention to provide a vertically aligned carbon nanotube separation membrane technology that combines carbon nanotube technology, which is a core new material of nanotechnology, with membrane technology to further enhance the permeability of existing membrane technology.

It is also an object of the present invention to provide a separation membrane technology for water treatment that increases the permeability and antibacterial property of existing reverse osmosis membrane technology by combining carbon nanotube technology with separation membrane technology.

In order to accomplish the above object, the present invention is characterized in that vertically arranged carbon nanotubes are densified and amorphous carbon on the outer wall of the carbon nanotube is removed by heat treatment, and both ends of the carbon nanotubes are cut by oxygen plasma treatment. Thereby providing a carbon nanotube structure.

Also, the present invention provides a carbon nanotube structure for water treatment characterized in that the density of compacted carbon nanotubes is 2.64 × 10 ¹¹ to 8.33 × 10 ¹¹ per cm 2.

The present invention also provides a carbon nanotube structure for water treatment characterized in that the length of the vertically arranged carbon nanotubes is 1 to 2 mm.

The present invention also provides a carbon nanotube structure for water treatment characterized in that the carbon nanotubes are single-walled carbon nanotubes or multi-walled carbon nanotubes.

The present invention also provides a carbon nanotube structure for water treatment characterized in that the average space size between the carbon nanotubes is 5 to 18 nm.

The present invention also provides a carbon nanotube structure for water treatment characterized in that the oxygen plasma treatment accelerates oxygen ions in a plasma state to be applied to the ends of the carbon nanotubes and cut.

The present invention also provides a method of fabricating a carbon nanotube, comprising: vertically arranging carbon nanotubes vertically; A densification step of densifying the carbon nanotubes to 2.64 × 10 ¹¹ to 8.33 × 10 ¹¹ per cm 2; A heat treatment step of performing heat treatment for removing amorphous carbon and defect sites; And cutting the ends of the vertically arranged carbon nanotubes by oxygen plasma treatment. The present invention also provides a method for manufacturing a water treatment carbon nanotube structure.

The present invention also provides a method for manufacturing a carbon nanotube structure for water treatment characterized in that the density of compacted carbon nanotubes is 2.64 × 10 ¹¹ to 8.33 × 10 ¹¹ per cm 2.

Also, the present invention provides a method for manufacturing a carbon nanotube structure for water treatment, wherein the length of the vertically arranged carbon nanotubes is 1 to 2 mm.

The present invention also provides a method for manufacturing a carbon nanotube structure for water treatment, wherein the carbon nanotubes are single-walled carbon nanotubes or multi-walled carbon nanotubes.

Also, the present invention provides a method for manufacturing a carbon nanotube structure for water treatment, wherein an average space size between the carbon nanotubes is 5 to 18 nm.

Also, the present invention provides a method for manufacturing a carbon nanotube structure for water treatment, wherein the temperature is elevated from atmospheric temperature to 600 ° C for 50 to 100 minutes.

Also, the present invention provides a method for manufacturing a carbon nanotube structure for water treatment, wherein the carbon nanotube tip cutting step is performed by accelerating oxygen ions in a plasma state and applying the oxygen ions to the ends of the carbon nanotubes.

The present invention also provides a water treatment separator comprising the carbon nanotube structure for water treatment or the carbon nanotube structure for water treatment manufactured by the manufacturing method.

The water treatment membrane according to the present invention has the effect of being utilized for seawater desalination by vertically aligned carbon nanotube membrane technology which surpasses permeability of existing membrane technology.

The water permeability of water according to the present invention is gradually increased according to the density of pores, although the pore size decreases as the mechanical density increases. However, the carbon nanotube structure of each carbon nanotube It can be seen that the tube has straightness without twisting and the permeability is improved.

The water treatment carbon nanotube structure according to the present invention was subjected to heat treatment to improve the performance of the membrane, thereby removing the amorphous carbon from the outer wall of the carbon nanotube, and the permeability was improved by about two times or more.

1 is a schematic view illustrating a process for manufacturing a water treatment carbon nanotube structure according to an embodiment of the present invention.
FIG. 2 is a schematic view of a vertically aligned carbon nanotube used in the present invention.
FIG. 3 is a SEM photograph of a carbon nanotube in which carbon nanotubes are arranged vertically.
4 is a photograph showing a comparison of areas of carbon nanotubes before and after the densification step according to an embodiment of the present invention.
5 shows a vertically aligned state of carbon nanotubes according to density.
6 shows the permeability and permeation rate of the carbon nanotube structure according to density.
FIG. 7 is a TGA (thermogravimetric analysis) curve according to the heat treatment temperature and the heat treatment time of the carbon nanotube structure according to the present invention.
FIG. 8 shows Raman spectra (a) and ID / IG ratio (b) of carbon nanotubes according to heat treatment time.
9 is a graph showing the permeability and permeation rate of the dense carbon nanotube before and after the heat treatment step.
10 shows a carbon nanotube structure obtained by cutting an end of a carbon nanotube by oxygen plasma treatment.
11 shows an XPS plot before and after a plasma treatment according to an embodiment of the present invention.
FIG. 12 is a graph showing data on permeability of Examples 1 to 3, Comparative Examples 1 and 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that, in the drawings, the same components or parts have the same reference numerals as much as possible. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as to avoid obscuring the subject matter of the present invention.

The terms " about ", " substantially ", etc. used to the extent that they are used herein are intended to be taken to mean an approximation of, or approximation to, the numerical values of manufacturing and material tolerances inherent in the meanings mentioned, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

The present invention relates to a method of fabricating a carbon nanotube, A densification step of densifying the carbon nanotubes to 2.64 × 10 ¹¹ to 8.33 × 10 ¹¹ per cm 2; A heat treatment step of performing heat treatment for removing amorphous carbon and defect sites; And a carbon nanotube tip cutting step of cutting the ends of the vertically arranged carbon nanotubes by an oxygen plasma treatment, thereby manufacturing a carbon nanotube structure for water treatment.

FIG. 1 is a schematic view of a process for manufacturing a water treatment carbon nanotube structure according to an embodiment of the present invention, and FIG. 2 is a schematic view of manufacturing a vertically aligned carbon nanotube used in the present invention.

The carbon nanotubes may be arranged vertically in the vertical alignment step. The method of vertically aligning the carbon nanotubes is not particularly limited, but it is preferable that the carbon nanotubes are vertically aligned using a metal catalyst.

Carbon nanotubes can grow in metal catalysts. After depositing aluminum oxide (Al ₂ O ₃ ) on silicon (Si), the Fe catalyst, which is a metal, is uniformly patterned using block copolymer lithography, Gas can be injected.

As the carrier gas, inert gas such as Ar, He, or N ₂ may be used. As the reaction gas, C ₂ H ₂ , CH _4, etc. may be used. When a carrier gas and a source gas are injected and a temperature of 700 to 900 ° C is applied, carbon of the source gas is bonded to the patterned metal catalyst and grown to form carbon nanotubes. The growth of carbon nanotubes can form vertically aligned carbon nanotubes with a uniform density and high density.

When the vertically aligned carbon nanotubes according to the present invention are vertically aligned using a metal catalyst as described above, carbon nanotubes having a diameter of 1 to 2 mm can be manufactured.

FIG. 3 is a SEM photograph of a carbon nanotube in which carbon nanotubes are arranged vertically.

Referring to FIG. 3, carbon nanotubes having a uniform height and a high density can be identified using an Fe catalyst. The vertically arranged carbon nanotubes are 1.3 mm in height and 5 nm in diameter arranged vertically.

The density of the vertically aligned carbon nanotube is about 8 × ¹⁰ 10 will have a density per individual 1㎠ used which may have a high density.

The vertically aligned carbon nanotubes may be single wall carbon nanotubes or multi wall carbon nanotubes. The number of walls of the carbon nanotube may be one to three layers.

The vertically arranged carbon nanotubes can densely close the spaces between the carbon nanotubes (densification step).

4 is a photograph showing a comparison of areas of carbon nanotubes before and after the densification step according to an embodiment of the present invention.

The method of densification is not particularly limited, and can be physically densified using mechanical densification.

The mechanical densification applies pressure to vertically align the carbon nanotube structure in at least two directions.

Referring to FIG. 4, the area of the first vertically aligned carbon nanotubes is A0, and when the area of the carbon nanotubes after mechanical clustering is A, A0 / A is densified to be 10. The size and density of the pores of the vertically aligned carbon nanotube structure can be controlled by mechanically applying a mechanical force in a direction perpendicular to the axis of the vertically arranged carbon nanotubes having a porous structure, It is possible to control the density per unit area of the vertically arranged carbon nanotubes and the size of the space between the carbon nanotubes.

5 shows a vertically aligned state of carbon nanotubes according to density.

It can be seen that the density of vertically aligned carbon nanotubes increases as the degree of mechanical densification increases.

In the present invention, the average space size between the carbon nanotubes is preferably about 5 to 18 nm.

As shown in FIG. 4, when the area of the first vertically aligned carbon nanotubes is A0 and the area of the carbon nanotubes after the mechanical densification is A, the A0 / A is increased by mechanical densification 3, 6 and 10, and a SEM photograph thereof is shown in FIG.

The average space size between the vertically arranged carbon nanotubes can be measured by the BJH method. The pore size before the densification is about 32.5 nm. In the case of the carbon nanotubes in which A0 / A is dense at 10, the carbon nanotube inner diameter The average diameter of the tube is 4.8 nm). The BJH method is a method for measuring the pore size of a porous material. The porous material is mainly permeated into pores of the porous material, the gas is absorbed and desorbed in the pores, and the pressure change of the gas generated during adsorption / desorption is measured And the pore size and size distribution of the porous material.

As can be seen from FIG. 5, it can be seen that the vertically arranged carbon nanotubes exhibit improved linearity without twisting.

By improving the straightness of the carbon nanotubes, the actual passage length of the water molecules can be shortened and the permeability of the membrane can be improved. Also, mechanically dense vertically aligned carbon nanotubes can be controlled in density per unit area, which may affect the permeability of the membrane. Therefore, in the present invention, the mechanical densification method is an effective method of controlling the arrangement characteristics having the linearity of vertically aligned carbon nanotubes, and thus the permeability can be improved.

In this case, the density of the carbon nanotubes is preferably 2.64 × 10 ¹¹ to 8.33 × 10 ¹¹ per 1 cm 2. It can be seen that the permeability of the carbon nanotubes is improved when it is within the above range.

6 shows the permeability and permeation rate of the carbon nanotube structure according to density.

Referring to FIG. 6, the permeability of the carbon nanotube structure was 3,287 ± 1,208, 4,272 ± 565, and 5,133 ± 1,459 LMH / bar at 2,328 ± 1,334 LMH / bar as the values of A0 / A increased to 1, 3, And it showed a high permeability despite having a long permeation length (thick film thickness).

That is, as the carbon nanotube structure is densified, the permeability increases. This is because the pore size (space size) decreases as the carbon nanotubes are densified, but the pore density increases and the twist of the carbon nanotube array decreases and the linearity increases. As a result, the carbon nanotube structure exhibits excellent permeability characteristics, and the mechanical densification method is an effective method for increasing the permeability of the carbon nanotube structure according to the present invention.

The permeability of the carbon nanotube structure according to the present invention is improved by mechanical densification. However, as shown in FIG. 6, the permeation rate of water is low.

This is due to the presence of amorphous carbon and defects on the outer wall of the carbon nanotube which can lower the flow rate of water molecules. The amorphous carbon and the defect sites are caused by the movement of water molecules through the outer wall of the carbon nanotube Interfere.

The present invention is characterized in that after the densification step, the amorphous carbon and the defect part are subjected to a heat treatment step for heat treatment for removal.

FIG. 7 is a TGA (thermogravimetric analysis) curve according to heat treatment temperature and heat treatment time of the carbon nanotube structure according to the present invention, and FIG. 8 shows Raman spectra and ID / IG ratio of carbon nanotubes according to heat treatment time.

The Raman spectrum of vertically aligned carbon nanotubes shows an ID / IG ratio of 1.08, which indicates that the intensity of the D peak is higher than that of the G peak. This means that the density of amorphous carbon and defects in the outer wall of the carbon nanotube is high And the functional group can be generated by the water that permeates.

Accordingly, the present invention can increase the permeation rate of water by removing amorphous carbon and suppressing the occurrence of defects.

The amorphous carbon of the outer wall is a factor affecting the performance of the carbon nanotube structure. Therefore, it was tried to improve the performance of the carbon nanotube structure by increasing the permeation rate of water molecules by removing it. The amorphous carbon on the outer wall of the carbon nanotube can be removed by thermal purification method under an ambient air atmosphere. The oxidation temperature of amorphous carbon in the outer wall is reported to be lower than that of sp2 bonding in the presence of oxygen.

Therefore, proper heat treatment conditions can suppress amorphous carbon while suppressing the generation of defects on the outer wall of the carbon nanotubes, and can suppress the generation of defects.

The heat treatment may be performed at a temperature of atmospheric temperature under an atmospheric pressure to gradually raise the temperature up to 600 ° C, preferably 50 to 100 minutes.

It is preferable that the proper temperature of the heat treatment for suppressing the amorphous carbon removal and the generation of the defective site is increased to 500 ° C and the heat treatment is continued.

As can be seen from FIG. 7, when the carbon sp2 bonded to the carbon nanotube wall is oxidized at a temperature higher than 600 deg. C in an atmospheric environment, rapid mass loss occurs. Elevated temperatures from ambient to 600 ° C show a relatively low mass loss of 5% due to oxidation of amorphous carbon. That is, it can be confirmed that the mass loss of carbon nanotubes heat-treated for 100 minutes is about 5%. Thus, the TGA curve shows that the carbon nanotubes were annealed in the atmosphere for about 100 minutes to remove amorphous carbon. The purity of the annealed carbon nanotubes was confirmed by the Raman spectra of the carbon nanotubes according to the annealing time. In the Raman spectra, the amorphous carbon appears in the D band and the sp2 bonded carbon appears in the G band. Therefore, the peak intensive ratio of G and D band (ID / IG) represents the purity of carbon nanotubes.

Referring to FIG. 8, amorphous carbon is removed from the carbon nanotube structure annealed for 100 minutes, and a low ID / IG ratio is shown. When the annealing time is increased for 100 minutes or more, Increase in ID / IG ratio due to increase.

As a result, the carbon nanotubes can be heat-treated for 100 minutes in an atmospheric environment to inhibit the generation of defects and efficiently remove amorphous carbon.

9 is a graph showing the permeability and permeation rate of the dense carbon nanotube before and after the heat treatment step.

The permeability and the permeation rate were measured using a carbon nanotube structure that was densified at a density of 10 and then annealed for 100 minutes while gradually increasing the temperature from atmospheric temperature to 600 ° C.

The graph of FIG. 9 shows the permeability and permeability of the carbon nanotube structure before and after the heat treatment. The permeability of the carbon nanotube structure with amorphous carbon removed to the outer wall was increased about twice as the permeation rate of water was increased about twice as compared with the carbon nanotube structure without heat treatment. These results show that the permeation rate of water molecules is improved by decreasing the flow resistance between the water molecules and the wall surface by removing the amorphous carbon on the outer wall of the carbon nanotube to provide a smooth carbon nanotube wall.

Therefore, the carbon nanotube structure according to the present invention has an excellent permeability and permeability.

The separation membrane can be used by using the carbon nanotube structure for water treatment according to the present invention, and it is possible to provide a separation membrane having excellent water permeability and permeation rate of water molecules through the outer wall of the carbon nanotube.

When the structure prepared by densifying and heat-treating the carbon nanotubes arranged vertically as described above is used as a separator, the permeability and permeation rate are significantly improved.

Also, in the present invention, after the heat treatment step, the end of the vertically aligned carbon nanotubes is subjected to a step of cutting the end of the carbon nanotubes by an oxygen plasma treatment.

10 shows a carbon nanotube structure obtained by cutting an end of a carbon nanotube by oxygen plasma treatment.

When the ends of the carbon nano-butt are cut, defects are generated. Due to such defects, water molecules can not pass through the pores of the carbon nanotubes. However, when the oxygen plasma treatment is performed as in the present invention, oxygen ions are attached to the defect sites to form hydrophilic functional groups (see FIG. 10). Therefore, water molecules can easily pass through.

More specifically, the oxygen plasma treatment refers to a technique in which oxygen ions are collided with a material and etched. When the oxygen gas is introduced into the plasma apparatus, oxygen ions are formed and accelerated oxygen ions are added to the ends of the carbon nanotubes to be cut. The plasma apparatus used in the present invention is not particularly limited, and a general plasma apparatus shown in the market is used.

In this case, the tip of the carbon nanotube is cut off, and a hydrophilic functional group is attached to the cut part, so that water molecules can easily pass through the carbon nanotube film.

When the end of the carbon nanotube is subjected to the oxygen plasma treatment, the end of the carbon nanotube is etched and removed. Therefore, it is possible to obtain vertically aligned carbon nanotubes with open ends at both ends. When used as a water treatment membrane, the water molecules can pass through the pores between the outer wall and the outer wall of the vertically arranged carbon nanotubes as well as the pores inside the carbon nanotubes A water treatment film having a high permeability can be obtained.

11 shows an XPS plot before and after a plasma treatment according to an embodiment of the present invention.

11 is a graph showing X-ray photoelectron spectroscopy (XPS) data for a carbon nanotube structure. Comparing the X-ray photoelectron spectroscopy (XPS) data before and after the oxygen plasma treatment, OH group and -COOH group are formed.

In the XPS data before plasma treatment, only the sp2 peak and 285 eV sp3 peak appear at 284 eV, and the sp2 peak represents the carbon atom doubly bonded to each other in the carbon nanotube. And the sp3 peak means an imperfect bonded carbon atom (defect) and an amorphous carbon, functional group, not a double bond.

After plasma treatment, two things can be seen. The intensity of sp3 peak is larger than that of sp2 peak. This means that the tip of the carbon nanotube is removed by etching and many defects are formed at the tip. The second shows that oxygen atoms are bonded to the defect at the end of the carbon nanotube, resulting in -OH (286 eV) and -COOH (289 eV). From the XPS results, it can be seen that the cap at the end of the CNT was removed from the oxygen plasma, the CNT tip was cut, and the tip of the CNT was changed to be hydrophilic.

Hereinafter, embodiments of the present invention will be described in detail.

Example  One

Vertical alignment of carbon nanotube structure

A silicon (Si) wafer is prepared, and a catalyst metal is deposited on a silicon (Si) wafer.

Ar, which is an inert gas, may be used as the carrier gas for preparing carbon nanotubes arranged vertically using a carrier gas and a reaction gas. C ₂ H ₂ is used as a reaction gas, and a temperature of about 900 ° C. And the vertically aligned carbon nanotubes are formed to have a rectangular planar shape. The grown carbon nanotubes can have a uniform height.

Densification step

The area of the first vertically aligned carbon nanotubes is A0, and when the area of the carbon nanotubes after mechanically dense is A, the density of A0 / A is increased to 10 by mechanical densification. The method of compacting the two surfaces of the vertically arranged carbon nanotubes is to press the two surfaces in close contact with each other by applying a mechanical force to the entire one surface in a direction perpendicular to the axis of the vertically arranged carbon nanotubes (see FIG. 4).

Heat treatment step

The densified structure was heated from the atmospheric temperature to 600 ° C, and heat treatment was performed for about 100 minutes.

Carbon nanotube End cutting step

The ends of the heat-treated carbon nanotubes are subjected to oxygen plasma treatment to remove the ends. In the room temperature atmosphere, oxygen is injected into the plasma apparatus to make it into an oxygen ion state. After accelerating the oxygen ions, the carbon nanotubes are cut at the tip of the carbon nanotubes.

When the oxygen gas is introduced into the plasma apparatus, oxygen ions are formed and accelerated oxygen ions are added to the ends of the carbon nanotubes to be cut.

The permeability experiment was conducted by allowing water (tap water) to permeate through the completed carbon nanotube structure.

Example  2 and Example  3

A0 / A was densified into 6 (Example 2) and 3 (Example 3) in the densification step in the same manner as in Example 1, respectively.

Comparative Example  One

The carbon nanotube structure was completed in the same manner as in Example 1 except that the "vertical alignment of the carbon nanotube structure" and the "densification step (densification of A0 / A at 10)" were performed in the same manner.

Comparative Example  2

After the steps of "vertically aligning the carbon nanotube structure" and "densification step (densifying A0 / A at 10") were performed in the same manner as in Example 1, both ends of the carbon nanotube structure were cut, The carbon nanotube structure was completed by cutting both ends using a microtome as a cutting tool without carrying out the process.

The permeabilities of Examples 1 to 3 and Comparative Examples 1 and 2 are summarized in Table 1 below.

division Permeability (LMH bar) Example 1 30200 Example 2 29800 Example 3 29150 Comparative Example 1 4900 Comparative Example 2 6200

FIG. 12 is a graph showing data on permeability of Examples 1 to 3, Comparative Examples 1 and 2.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. It will be clear to those who have knowledge of.

Claims (14)

The vertically arranged carbon nanotubes are mechanically densified in the same direction as the array direction and in the vertical direction,
The amorphous carbon on the outer wall of the carbon nanotube is removed by heat treatment,
Both ends of the carbon nanotubes were cut by the oxygen plasma treatment,
The -OH group or -COOH group is formed in the cut defect,
Wherein the voids and the permeability are improved by using the inner pores of the cylinder-shaped vertically arranged carbon nanotubes having open ends at both ends and the gap between the outer wall and the outer wall of the carbon nanotubes.
The method according to claim 1,
Wherein the density of the compacted carbon nanotubes is 2.64 × 10 ¹¹ to 8.33 × 10 ¹¹ per cm 2.
The method according to claim 1,
Wherein the length of the vertically arranged carbon nanotubes is 1 to 2 mm.
The method according to claim 1,
Wherein the carbon nanotubes are single-walled carbon nanotubes or multi-walled carbon nanotubes.
The method according to claim 1,
Wherein the average space size between the carbon nanotubes is 5 to 18 nm.
The method according to claim 1,
Wherein the oxygen plasma treatment accelerates oxygen ions in a plasma state to apply to the tip of the carbon nanotube to cut the carbon nanotube structure.
Vertically arranging the carbon nanotubes vertically;
Densifying the vertically arranged carbon nanotubes to 2.64 × 10 ¹¹ to 8.33 × 10 ¹¹ per cm 2 by applying a mechanical force in a direction perpendicular to the direction of arrangement;
A heat treatment step of performing heat treatment for removing amorphous carbon and defect sites; And
Both ends of the carbon nanotubes were cut by the oxygen plasma treatment,
The -OH group or -COOH group is formed in the cut defect,
And a carbon nanotube tip cutting step of improving the porosity and permeability by utilizing the internal pores of the vertically arranged carbon nanotubes having open ends at both ends and the gap between the outer wall and the outer wall of the carbon nanotubes, ≪ / RTI >
delete 8. The method of claim 7,
Wherein the length of the vertically arranged carbon nanotubes is 1 to 2 mm.
8. The method of claim 7,
Wherein the carbon nanotubes are single-walled carbon nanotubes or multi-walled carbon nanotubes.
8. The method of claim 7,
Wherein the average space size between the carbon nanotubes is 5 to 10 nm.
8. The method of claim 7,
Wherein the carbon nanotube structure is heated from an atmospheric temperature to 600 ° C for 50 to 100 minutes.
8. The method of claim 7,
Wherein the cutting step of the carbon nanotubes is performed by accelerating oxygen ions in a plasma state to cut the carbon nanotubes on the ends of the carbon nanotubes.
A water treatment carbon nanotube structure according to any one of claims 1 to 6 or a water treatment carbon nanotube structure produced by the manufacturing method according to any one of claims 7 to 9, Separation membrane for water treatment.

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