Toluene and benzene were eliminated using multi-walled carbon nanotubes (MWCNTs). In order to investigate influence of acid treatment on the MWCNTs adsorption capacities, the MWCNTs were functionalized by nitric acid (10 M) under reflux conditions for 2 h. Fourier transform infrared (FTIR) and Raman spectroscopy were employed to confirm the formation of functional groups on the nanotubes su...