Method for purification of as-produced fullerene nanotubes

• US 7,354,563 B2
• Filed: 08/22/2006
• Issued: 04/08/2008
• Est. Priority Date: 03/07/1997
• Status: Expired due to Fees

• Current Assignee: Rice University
• Original Assignee: Rice University
• Inventors: Smalley, Richard E., Liu, Jie, Rinzler, Andrew G., Nikolaev, Pavel, Colbert, Daniel T., Thess, Andreas, Hafner, Jason H., Smith, Ken, Guo, Ting, Dai, Hongjie
• Primary Examiner(s): HENDRICKSON, STUART L
• Application Number:
  US11/507,960
• Publication Number:
  US 20080063588A1
• Time in Patent Office: 595 Days
• Field of Search: 423/445.B, 423/447.1, 423/461, 977/845
• US Class Current: 423/447.1
• CPC Class Codes: B01J 19/081 employing particle radiation or gamma-radiation
• CPC Class Codes: B01J 19/087 employing electric or magnetic energy
• CPC Class Codes: B01J 19/10 employing sonic or ultrasonic vibrations
• CPC Class Codes: B01J 19/121 Coherent waves, e.g. laser beams lasers per se H01S3/00
• CPC Class Codes: B01J 19/126 Microwaves
• CPC Class Codes: B01J 19/129 Radiofrequency
• CPC Class Codes: B01J 21/185 Carbon nanotubes carbon nanotubes per se C01B32/15
• CPC Class Codes: B01J 2219/00078 Fingers
• CPC Class Codes: B01J 2219/0892 involving catalytically active material
• CPC Class Codes: B01J 23/74 Iron group metals
• CPC Class Codes: B01J 23/755 Nickel
• CPC Class Codes: B01J 23/8913 Cobalt and noble metals
• CPC Class Codes: B01J 37/0238 via the gaseous phase-sublimation
• CPC Class Codes: B01J 37/349 making use of flames, plasmas or lasers
• CPC Class Codes: B82B 3/00 Manufacture or treatment of nanostructures by manipulation of individual atoms or molecules, or limited collections of atoms or molecules as discrete units
• CPC Class Codes: C01B 2202/02 Single-walled nanotubes
• CPC Class Codes: C01B 32/156 After-treatment
• CPC Class Codes: C01B 32/162 characterised by catalysts
• CPC Class Codes: C01B 32/17 Purification
• CPC Class Codes: D01F 9/12 Carbon filaments; Apparatus specially adapted for the manufacture thereof
• CPC Class Codes: D01F 9/127 : by thermal decomposition of hydrocarbon gases or vapours or other carbon-containing compounds in the form of gas or vapour, e.g. carbon monoxide, alcohols
• CPC Class Codes: D21H 27/00 : Special paper not otherwise provided for, e.g. made by multi-step processes
• CPC Class Codes: G11B 9/1418 : Disposition or mounting of heads or record carriers G11B17/00 and G11B19/00 take precedence
• CPC Class Codes: G11B 9/1445 : switching at least one head in operating function; Controlling the relative spacing to keep the head operative, e.g. for allowing a tunnel current flow
• CPC Class Codes: G11B 9/1472 : characterised by the form
• CPC Class Codes: G11B 9/149 : characterised by the memorising material or structure
• CPC Class Codes: G11C 13/0014 : comprising cells based on organic memory material
• CPC Class Codes: G11C 13/0019 : comprising bio-molecules
• CPC Class Codes: G11C 13/025 : using fullerenes, e.g. C60, or nanotubes, e.g. carbon or silicon nanotubes
• CPC Class Codes: G11C 2213/16 : Memory cell being a nanotube, e.g. suspended nanotube
• CPC Class Codes: G11C 2213/71 : Three dimensional array
• CPC Class Codes: G11C 2213/81 : Array wherein the array conductors, e.g. word lines, bit lines, are made of nanowires
• CPC Class Codes: H01G 9/2059 : comprising an organic dye as the active light absorbing material, e.g. adsorbed on an electrode or dissolved in solution
• CPC Class Codes: H01L 31/0352 : characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions
• CPC Class Codes: H01L 31/06 : characterised by potential barriers
• CPC Class Codes: H01L 31/18 : Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
• CPC Class Codes: H01M 10/0525 : Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 4/133 : Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/525 : of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/583 : Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/587 : for inserting or intercalating light metals
• CPC Class Codes: H01M 4/625 : Carbon or graphite
• CPC Class Codes: Y02E 10/542 : Dye sensitized solar cells
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10S 977/70 : Nanostructure
• CPC Class Codes: Y10S 977/742 : Carbon nanotubes, CNTs
• CPC Class Codes: Y10S 977/745 : having a modified surface
• CPC Class Codes: Y10S 977/748 : Modified with atoms or molecules bonded to the surface
• CPC Class Codes: Y10S 977/75 : Single-walled
• CPC Class Codes: Y10S 977/753 : with polymeric or organic binder
• CPC Class Codes: Y10S 977/789 : in array format
• CPC Class Codes: Y10S 977/842 : for carbon nanotubes or fullerenes
• CPC Class Codes: Y10S 977/843 : Gas phase catalytic growth, i.e. chemical vapor deposition
• CPC Class Codes: Y10S 977/845 : Purification or separation of fullerenes or nanotubes
• CPC Class Codes: Y10S 977/847 : Surface modifications, e.g. functionalization, coating
• CPC Class Codes: Y10S 977/848 : Tube end modifications, e.g. capping, joining, splicing
• CPC Class Codes: Y10S 977/849 : with scanning probe
• CPC Class Codes: Y10S 977/882 : Assembling of separate components, e.g. by attaching
• CPC Class Codes: Y10S 977/948 : Energy storage/generating using nanostructure, e.g. fuel cell, battery
• CPC Class Codes: Y10T 428/24058 : including grain, strips, or filamentary elements in respective layers or components in angular relation
• CPC Class Codes: Y10T 428/2918 : including free carbon or carbide or therewith [not as steel]
• CPC Class Codes: Y10T 428/292 : In coating or impregnation
• CPC Class Codes: Y10T 428/30 : Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

This invention relates generally to a fullerene nanotube purification process and more particularly to a purification process that comprises heating the fullerene nanotube-containing felt under oxidizing conditions to remove the amorphous carbon deposits and other contaminating materials. In a preferred mode of this purification procedure, the felt is heated in an aqueous solution of an inorganic oxidant, such as nitric acid, a mixture of hydrogen peroxide and sulfuric acid, or a potassium permanganate. Preferably, fullerene nanotube-containing felts are refluxed in an aqueous solution of an oxidizing acid at a concentration high enough to etch away amorphous carbon deposits within a practical time frame, but not so high that the fullerene nanotube material will be etched to a significant degree. When material having a high proportion of fullerene nanotubes is purified, the preparation produced will be enriched in fullerene nanotubes, so that the fullerene nanotubes are substantially free of other material.

Claims

1. A method for purifying a mixture comprising fullerene nanotubes and amorphous carbon contaminate, said method comprising the steps of:

(a) heating said mixture under oxidizing conditions sufficient to remove the said amorphous carbon; and

(b) recovering a product comprising at least about 80% by weight of fullerene nanotubes, wherein the product is washed with a solution comprising a surfactant.

2. The method of claim 1 wherein the surfactant is sodium dodecyl sulfate.

3. The method of claim 1 wherein the surfactant is a non-ionic surfactant.

4. A method for purifying a mixture comprising fullerene nanotubes and amorphous carbon contaminate, said method comprising the steps of:

(a) heating said mixture under oxidizing conditions sufficient to remove the said amorphous carbon, wherein said oxidizing conditions comprise an aqueous solution of an inorganic oxidant;

(b) recovering a product comprising at least about 80% by weight of fullerene nanotubes; and

(c) subjecting the product of step (b) to a saponification treatment.

5. The method of claim 4 wherein said saponification treatment comprises contacting said product with a basic solution.

6. The method of claim 5 wherein said basic solution comprises sodium hydroxide.

7. The method of claim 5 additionally comprising the step of neutralizing the saponified product with an acid.

8. The method of claim 7 wherein said acid is hydrochloric acid.

9. The method of claim 7 additionally comprising the step of recovering a solid product from the saponified, neutralized product.

10. The method of claim 9 wherein said product is recovered by a method selected from the group consisting of filtration, settling by gravity, chemical flocculators, and liquid cycloning.

11. The method of claim 9 wherein said solid product is a paper-like two-dimensional product.

12. The method of claim 11 additionally comprising the step of drying the product.

13. The method of claim 12 wherein said product is dried at about 850°

C. in a hydrogen gas atmosphere.