A simple, effective and efficient purification method for single-wall carbon nanotubes (SWCNTs) prepared by hydrogen arc discharge has been developed. Hydrogen treatment has been used to remove the amorphous carbon and graphene sheets encapsulating Fe catalyst nanoparticles. The exposed Fe nanoparticles can be easily dissolved in concentrated hydrochloric acid. Carbon content higher than 99 wt.% can be achieved. The small SWCNTs with a diameter of 0.9 nm are found to survive during the purification processes. This new purification method enables us to obtain purified SWCNTs with high-crystallinity and without obvious damage. (C) 2010 Elsevier B.V. All rights reserved.