ADSORPTION CHARACTERISTICS OF CARBON NANOTUBES BY LOW TEMPERATURE NITROGEN ADSORPTION EXPERIMENT

In order to study the characteristics of carbon nanotubes, a series of N-2 at 77.4 K adsorption experiment were carried out in the laboratory, and the adsorption isotherms of different types of carbon nanotubes (CNTs) were obtained. The micropore and mesopore size distributions of CNTs were determined using the modified Horvath-Kawazoe and BJH models based on the adsorption-desorption isotherms. And the adsorption capacities of CNTs in different adsorption stages, such as the micropore volume filling stage, multi-layer adsorption stage and capillary condensation stage, were evaluated based on the adsorption isotherms. The results show that the maximum pore size of CNTs corresponding to the pore volume filling is about 9 nm. The amount of N-2 adsorbed in the tube of CNTs is negative with the pore size. However, the amount of N-2 in the status of capillary condensation is positive with the pore size of CNTs.