Diffusion-controlled adsorption–desorption of C6 hydrocarbons by multiwall carbon nanotubes

Abstract

The adsorption–desorption of n-hexane, cyclohexane, and benzene on multiwall carbon nanotubes is investigated using the quartz crystal microbalance technique. Desorption kinetics is found to be diffusion-controlled. The standard Fickian diffusion models for short and long times have been applied to quantify the desorption kinetics. Considering surface diffusion as a rate-limiting step of desorption, the estimated surface diffusion coefficients for all hydrocarbons are of order 10-14 m2/s. This is an order of magnitude lower compared to surface diffusion coefficient on various carbon materials. The surface diffusion coefficient increases with an increase in surface loading.