Influence of conversion parameters of waste tires to activated carbon on adsorption of dibenzothiophene from model fuels

Activated carbon was prepared from end-of-life tires, and its surface functional groups were enhanced by wet chemical oxidation using nitric acid. The carbonization and activation temperatures were optimized. The obtained material was characterized using a Brunauer-Emmett-Teller surface area analyzer, a Fourier transform infrared spectroscope and a scanning electron microscope coupled with an energy dispersive spectroscope. It was evaluated for adsorptive desulfurization of dibenzothiophene (DBT) in a model fuel. Five factors (dosage, concentration of the sulfur compounds, contact time, column length, and flow rate) were varied using a 16 factorial design experiment. The optimum carbonization and activation temperatures that yielded a 473 m²/g surface area of the adsorbent for 5 h were 500 °C and 900 °C, respectively. The interaction plot revealed that the adsorbent dosage, column length and dosage had the most influence on the percentage removal of DBT. The kinetic data for the adsorption process complied to a pseudo-second-order kinetic model with an R² of 0.999, and the surface adsorption and intraparticle diffusion operated concurrently. The equilibrium adsorption is best fitted to the Freundlich isotherm model. The efficiency of the carbon prepared in this work is comparable to others on adsorptive desulfurization, and the results are promising, hence it should be tested for industrial applications.