Study of properties of multi-walled carbon nanotubes (MWCNTs) as gas chromatographic column packing material
The purified MWCNTs (PMWCNTs), prepared by catalytic decomposition of methane, activated carbon and graphitized carbon black ( Carbopack B) were used as gas chromatographic column packing materials. Their characteristics of separation of aromatic hydrocarbons, alkanes, halogenated hydrocarbons, ketones, ethers, esters and alcohols were compared. PMWCNTs and Carbopack B modified with 5% ( w/w) Carbowax 20M were also used as gas chromatographic column packing materials to separate ketones, ethers, esters, alcohols and organic acids for comparison of their separation properties. The results show that PMWCNTs are excellent packing materials. Comparing to Carbopack B with the same surface area, PMWCNTs has the following characteristics: having stronger retention ability, suitable for the separation of compounds with relatively low boiling points, showing symmetric peaks for polar compounds due to its more homogeneous surface, having lower theoretical plate number. Similar to Carbopack B, PMWCNTs modified with 5% (w/w) Carbowax 20M can be used to separate polar compounds, even lower organic acids.