The adsorption kinetics of diesel oil by multi-walled carbon nanotubes (MWCNTs) was investigated using static adsorption experiment and compared with activated carbon. The results show that the adsorption quantities on both the MWCNTs and activated carbon increase fast in the first 10 min

and the adsorption equilibrium can be reached in about 60 min

while the adsorption capacity on MWCNTs is far higher than activated carbon. The kinetic analysis shows that the adsorption kinetics can be accurately represented by a pseudo second-order model. The activation energy (Ea) of 14.21 kJ·mol-1

determined by the Arrhenius law

suggests that physisorption dominates the adsorption of diesel oil 2# onto MWCNTs. The analyzing results with intraparticle diffusion model show that the adsorption mechanism is complex for MWCNTs

consisting of external surface adsorption

internal diffusion in large interstitial pores and in small interstitial pores between the tubes

while for activated carbon it consists of external surface and intraparticle diffusion stages and is strongly influenced by the boundary layer. Initial adsorption behavior is found in the adsorption process of diesel oil onto MWCNTs. The adsorption of three diesel oils at constant temperature (298 K) and that of diesel oil 2# at different temperatures (288

298 and 308 K) show intermediately initial adsorption behavior. For diesel oil 2#

with the increase of temperature

the initial adsorption enhances

and at 318 K

intensive initial adsorption occurs.