Photochemical vapor generation for removing nickel impurities from carbon nanotubes and its real-time monitoring by atomic fluorescence spectrometry

A new method was proposed to remove trace nickel catalyst impurities from carbon nanotube (CNT) materials by the use of UV-induced photochemical carbonyl generation, and the process was real-time monitored by atomic fluorescence spectrometry. The CNTs were purified under mild optimal experimental conditions, and the characteristics of the purified CNTs were kept well. After purification, the content of nickel in the CNT materials was reduced from 1% to 0.4%, with a removal efficiency of 60%. The produced volatile nickel carbonyl was separated and introduced into an argon/hydrogen flame atomizer-atomic fluorescence spectrometer for measuring nickel atomic fluorescence signal to real-time monitor the purification process. (C) 2014 Elsevier B.V. All rights reserved.