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GC separation with nanotubes
20 July 2006
Devices lined with carbon nanotubes will improve industrial separation processes, claim researchers in the US.
Somenath Mitra and colleagues from the New Jersey Institute of Technology, US, have made single wall carbon nanotubes (SWCNTs) inside a long capillary tube, and demonstrated their use as gas chromatography (GC) columns.
Mitra developed a simple and quick method to self-assemble SWCNTs inside long silica-lined steel capillary tubing. He used the lined capillary tubes to successfully separate a variety of analytes, such as hydrocarbons. The reproducibility in retention time of the columns was comparable with commercial GC columns.
The SWCNTs are self-assembled by a single catalytic step that takes about 15 minutes to complete. 'The extremely high surface area of nanotubes means that volatile compounds can be separated. Nanotubes can also give high-resolution separation and extend the range of compounds that can be separated,' said Mitra.
The self-assembly of SWCNTs inside large structures is a significant step, said Mitra. 'This approach will open the door to larger scale applications of SWCNTs in a variety of chemical separations and processing, such as air pollution control, water purification and gas separation.'
Hundreds of tons of carbon are extensively used in the chemical industry. 'It is envisioned that the ability to fabricate nanotube coated structures will eventually replace traditional activated charcoal and related sorbents in many industrial-scale applications,' Mitra said.
ReferencesM Karwa, Z Iqbal and S Mitra, J. Mater. Chem., 2006, 16, 2890