design and synthesis of carbon nanotubes for adsorption utilities: an approach to direct preparation by mechanical milling at room temperature

The carbon nanotubes (cnts) were produced by mechanical milling of hexane in the presence of two different catalysts (amorphous and crystalline fe) at ar atmosphere. raman spectroscopy, fourier-transform infrared spectroscopy, transmission electron microscopy, high-resolution scanning electron microscopy, brunauer–emmett–teller (bet) and thermal analysis were employed to characterize the cnts. the results showed that the amorphous catalyst induced more structural defects in cnts respect to the crystalline catalyst. the ratio of single wall to multiwall cnts of prepared samples were about 0.31 and 7.3 for crystalline and amorphous catalyst, respectively. moreover, the bet results confirmed the higher adsorption capacity of the sample prepared by amorphous catalyst due to their higher structural defects.