Meijo University (Nagoya-shi, JP) researchers Yoshinori Ando, Xinluo Zhao and Sakae Inoue in U.S. Patent Application 20090285745 detail a process to produce high purity single wall carbon nanotubes cheaply on an industrial scale in an using an advanced arc discharge process with iron nanoparticles and hydrogen peroxide. The iron particles have an average particle diameter of 100 nm or smaller. Nickel/yttrium nanoparticles are also used as the catalyst metals in the process. Meijo University carbon nanotube-purifying material typically has a composition in which iron particles with an average particle size of 5 nm to 100 nm (for example, 5 nm to 30 nm) are dispersed as amorphous carbon-enveloped composite particles. This enables an efficient carbon nanotube purification based on an effective utilization of the iron particles.