Carbon nanotube separation method and separation apparatus

Patent metadata

Field	Value
Publication number	US-12415729-B2
Application number	US-202017629156-A
Country	US
Kind code	B2
Filing date	Jul 20, 2020
Priority date	Jul 24, 2019
Publication date	Sep 16, 2025
Grant date	Sep 16, 2025

Abstract

The object of the present invention is to provide a separation method and a separation apparatus for carbon nanotubes capable of separating a mixture of carbon nanotubes in a highly efficient, inexpensive and simple manner. The present invention relates to a carbon nanotube separation method comprising: a step of preparing a dispersion liquid including a mixture of two or more types of carbon nanotubes having different zeta potentials; a step of introducing the dispersion liquid into a flow path formed between a first electrode having holes for allowing the dispersion liquid to pass therethrough, and a second electrode arranged so as to face the first electrode; a step of applying a DC voltage to the first electrode and the second electrode while the dispersion liquid is flowing through the flow path; and, a step of continuously collecting a dispersion liquid including carbon nanotubes separated to a first electrode side upon application of the voltage from an opposite side to the flow path with respect to the first electrode, and at the same time, continuously collecting a dispersion liquid including carbon nanotubes separated to a second electrode side from a downstream side of the flow path.

First claim

The invention claimed is:

1. A carbon nanotube separation method comprising:
preparing a dispersion liquid comprising a mixture of two or more types of carbon nanotubes having different zeta potentials;
introducing the dispersion liquid into a flow path formed between a first electrode having holes for allowing the dispersion liquid to pass therethrough, and a second electrode arranged so as to face the first electrode, wherein a separator is stacked on a flow path side of the first electrode, and a pore diameter of the separator is equal to 50 nm to 20 μm;
applying a DC voltage to the first electrode and the second electrode while the dispersion liquid is flowing through the flow path; and
continuously collecting a dispersion liquid comprising carbon nanotubes separated to a first electrode side upon application of the voltage from an opposite side to the flow path with respect to the first electrode, and at the same time, continuously collecting a dispersion liquid comprising carbon nanotubes separated to a second electrode side from a downstream side of the flow path.

2. The separation method according to claim 1 , wherein continuously collecting a dispersion liquid comprising carbon nanotubes separated to a first electrode side from a first collection port is performed while sucking from the first collection port side.

3. The separation method according to claim 1 , wherein the mixture of two or more types of carbon nanotubes having different zeta potentials is a mixture of metallic single-walled carbon nanotubes and semiconducting single-walled carbon nanotubes.

4. The separation method according to claim 1 , wherein the second electrode has a shape of a liquid flow adjusting plate having one or a plurality of grooves extending in a flow direction on a surface thereof on a flow path side.

5. The separation method according to claim 4 , wherein a flow path inflow port side of the liquid flow adjusting plate has a streamline shape, the streamline shape being a shape in which a cross-sectional area of the flow path is represented by a function decreasing monotonically with respect to distance, and a differential function thereof is continuous.

6. A production method for carbon nanotubes comprising semiconducting single-walled carbon nanotubes of more than 67% by mass using the separation method according to claim 1 .

7. The production method for carbon nanotubes comprising metallic single-walled carbon nanotubes of more than 34% by mass using the separation method according to claim 1 .

8. A production method for an aligned carbon nanotube film comprising:
preparing a dispersion liquid comprising a mixture of two or more types of carbon nanotubes having different zeta potentials;
introducing the dispersion liquid into a flow path formed between a first electrode having a separator stacked thereon on a flow path side, wherein a pore diameter of the separator is equal to 10 nm to 1000 nm, and has holes for allowing the dispersion liquid to pass therethrough, and a second electrode arranged so as to face the first electrode;
applying a DC voltage to the first electrode and the second electrode while the dispersion liquid is flowing through the flow path; and
causing a part of a dispersion solvent liquid of the dispersion liquid to permeate through the first electrode, whereby one ends of at least some of carbon nanotubes separated to the first electrode side are fixed in pores of a separator stacked on the first electrode or in the vicinity of the pores, and at the same time, aligning the carbon nanotubes having the one ends fixed to the separator in one direction on the separator by flow of a dispersion liquid flowing in a downstream direction through the flow path.

9. A separation apparatus for separating two or more types of carbon nanotubes having different zeta potentials, comprising:
a flow path which is formed between a first electrode having holes for allowing a dispersion liquid to pass therethrough, and a second electrode arranged so as to face the first electrode to cause a dispersion liquid of a mixture of carbon nanotubes to flow therethrough;
a separator stacked on a flow path side of the first electrode, wherein a pore diameter of the separator is equal to 50 nm to 20 μm;
a DC voltage power supply for applying one of the first electrode and the second electrode to an anode and applying the other to a cathode; and
a first collection port for collecting a permeating liquid which has passed through the first electrode, and a second collection port provided on a downstream side of the flow path.

10. The separation apparatus according to claim 9 , wherein the second electrode has a shape of a liquid flow adjusting plate having a plurality of grooves extending in a flow direction of the flow path on a surface thereof on a flow path side.

11. The separation apparatus according to claim 10 , wherein a flow path inflow port side of the liquid flow adjusting plate has a streamline shape, the streamline shape being a shape in which a cross-sectional area of the flow path is represented by a function decreasing monotonically with respect to distance, and a differential function thereof is continuous.

12. The separation apparatus according to claim 9 , wherein the DC voltage power supply is a variable DC voltage power supply.

13. The separation apparatus according to claim 9 for producing an aligned carbon nanotube film.

14. The separation method according to claim 1 , wherein the pore diameter of the separator is equal to 100 nm to 10 μm.

15. The separation method according to claim 14 , wherein the pore diameter of the separator is equal to 200 nm to 1 μm.

16. The separation apparatus according to claim 9 , wherein the pore diameter of the separator is equal to 100 nm to 10 μm.

17. The separation apparatus according to claim 16 , wherein the pore diameter of the separator is equal to 200 nm to 1 μm.

18. The production method according to claim 8 , wherein the pore diameter of the separator is equal to 50 nm to 800 nm.

19. The production method according to claim 18 , wherein the pore diameter of the separator is equal to 100 nm to 500 nm.

Assignees

• Nec Corp
• Univ Meijo

Inventors

• Yuge Ryota
• Iijima Sumio

Classifications

• C25D13/02

  with inorganic material · CPC title

• C01B2202/22

  Electronic properties · CPC title

• C01B2202/08

  Aligned nanotubes · CPC title

• C01B2202/02

  Single-walled nanotubes · CPC title

• B03C5/02

  Separators · CPC title