Kinetic and intraparticle diffusion studies of carbon nanotubes-titania for desulfurization of fuels

The authors report on the kinetics, pseudo first-order model, pseudo second-order model, and intraparticle diffusion mechanism. Thus, the experimental data of the adsorption of thiophene, benzothiophene, and dibenzothiophene on a material of carbon nanotubes-titania were fitted to the kinetics and intraparticle diffusion models. The kinetics parameters of qe and correlation coefficient indicated that the data are not fitted with the pseudo first-order model while they are well fitted to the pseudo second-order model with R-2 of more than 0.99 and the maximum adsorption capacities qe calculated from the pseudo second order model are in accordance with the experimental values for the three sulfur compounds in a model fuel. The results indicated that the adsorbent has a higher adsorption efficiency toward DBT over the other two sulfur compounds. Fitting the data to the intraparticle diffusion model indicated the intraparticle diffusion was not only rate-controlling step and hence it can be suggested that the surface adsorption and intraparticle diffusion were concurrently operating. The experimental results demonstrate that the combining of titania and carbon nanotubes is a promising material, which can be used in desulfurization.