Abstract for presentation at Chemeca 2007

Single-Walled Carbon Nanotubes (SWNTs) are of great interest because of their superb properties with several potential applications. However, the great potential of SWNTs is prohibited by the impurity derived from the production step. Therefore, the objective of this study was to develop an effective method for the purification of SWNTs. As-prepared SWNTs samples synthesized from the dissproportionnation of CO over a Co-Mo/SiO2 catalyst were used in this study. The proposed method for the purification of SWNTs consisted of four sequential steps: oxidative pretreatment, acid treatment, silica dissolution, and froth flotation. The as-prepared SWNTs sample was first oxidized at 250 oC to convert the metal catalysts into metal oxides, resulting in increasing the exposure surface of the catalysts. After that, the oxidized sample was further treated with HCl in which 90% removal of the catalysts was achieved as compared to 10% removal for the sample without the oxidative pretreatment. For the silica dissolution step, NaOH was applied to increase the purity up to 35% as compared to the original purity of 2.42%. Finally, froth flotation was used to separate SWNTs from silica as well as to concentrate SWNTs by comparing two types of surfactants: sodium dodecyl benzene sulfonate (SDBS) and alcohol ethoxylate surfonic L24-7. From the results, the use of SDBS, an anionic surfactant, provided the highest SWNTs purity up to 69.3% at 0.5 CMC and 5pH as compared to 64.82% at 0.75 CMC for Surfonic L24-7, a nonionic surfactant. Moreover, these methods were not destroyed the properties of SWNTs.