A technique of purification process of single-walled carbon nanotubes with air.

A technique of purifying SWCNTs has been developed by means of oxidizing carbonaceous particles with air using fluidized-bed. Air was introduced into the fluidized-bed by pump with controllable flux. The powders were "boiling" at a temperature of 550 degrees C for 50 min. With this technique, the flux can be controlled simply. The fluidized-bed was applied as the heating apparatus instead of rotated quartz tubes. The air and the powders can be mixed with each other more sufficiently. Characteristics of the raw and purified powder were presented using Raman spectroscopy and transmission electronic microscopy (TEM), revealing that the purified powder is free from carbonaceous particles.