METHOD FOR PURIFYING MULTI-WALLED CARBON NANOTUBES
First Claim
1. A method for purifying a multi-walled carbon nanotube, the method comprising:
- adding a multi-walled carbon nanotube synthesized by a vapor phase process to a nitric acid aqueous solution of not lower than 0.2 mol/L so as to dissolve a catalyst metal present in the multi-walled carbon nanotube,performing solid-liquid separation to isolate solid matter, andsubjecting the solid matter to heat treatment at a temperature higher than 150°
C.
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Abstract
A method comprising adding a multi-walled carbon nanotube synthesized by the vapor phase process to a nitric acid aqueous solution of not lower than 0.2 mol/L so as to dissolve a catalyst metal present in the multi-walled carbon nanotube, performing solid-liquid separation to isolate solid matter, and subjecting the isolated solid matter to heat treatment at a temperature higher than 150° C. gives a purified multi-walled carbon nanotube in which the amount of a metallic element left in the multi-walled carbon nanotube originating the catalyst metal is not smaller than 1000 ppm and not larger than 8000 ppm determined by ICP optical emission spectrometry and the amount of an anion left in the multi-walled carbon nanotube originating in the acid is smaller than 20 ppm determined by ion chromatography analysis.
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Citations
11 Claims
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1. A method for purifying a multi-walled carbon nanotube, the method comprising:
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adding a multi-walled carbon nanotube synthesized by a vapor phase process to a nitric acid aqueous solution of not lower than 0.2 mol/L so as to dissolve a catalyst metal present in the multi-walled carbon nanotube, performing solid-liquid separation to isolate solid matter, and subjecting the solid matter to heat treatment at a temperature higher than 150°
C. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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- 8. A purified multi-walled carbon nanotube synthesized by a vapor phase process and then washed with an acid, wherein the amount of a metallic element left in the multi-walled carbon nanotube originating in a catalyst metal is not smaller than 1000 ppm and not larger than 8000 ppm determined by ICP optical emission spectrometry and the amount of an anion left in the multi-walled carbon nanotube originating in the acid is smaller than 20 ppm determined by ion chromatography analysis.
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11. A method for producing a purified multi-walled carbon nanotube, the method comprising
a step of preparing a multi-walled carbon nanotube by a supported catalyst method, a step of adding the prepared multi-walled carbon nanotube to a nitric acid aqueous solution of not lower than 0.2 mol/L, a step of performing solid-liquid separation to isolate the acid-treated multi-walled carbon nanotube, and a step of subjecting the isolated multi-walled carbon nanotube to heat treatment at a temperature higher than 150° - C.
Specification