Adsorption in single-walled carbon nanotubes by experiments and molecular simulation II: Effect of morphology and temperature on organic adsorption

In this study, hexane adsorption on single-walled carbon nanotube (SWNT) bundles was studied using the methodology developed in part I of this series of papers. First, hexane adsorption capacities of two purified SWNT samples was gravimetrically determined at isothermal conditions of 25, 37 and 50°C for 10 ^-4 < p/p _o < 0.9, where p/p _o is hexane vapor pressure relative to its saturation pressure. Next, simulation of hexane adsorption under similar temperature and pressure conditions were performed on the external and internal sites of nanotube bundles of diameters same as those in experimental samples. The internal adsorption was adjusted to incorporate the information about the fraction of open nanotubes present in the sample, as determined in part I; and total adsorption was calculated by summation of external and internal adsorption in the bundles. Comparison of experimental and simulated hexane adsorption capacities demonstrated the soundness of the methodology developed in part I, importance of organic adsorption on the peripheral surface of the bundles, limiting adsorption capacities of samples and effect of temperature on organic adsorption in nanotubes.