Enhancement of dibenzothiophene adsorption on activated carbons by surface modification using low temperature oxygen plasma

Application of low temperature oxygen plasma was proposed to modify activated carbons (ACs) for enhancing their adsorption toward dibenzothiophene (DBT) in a model diesel fuel. The textural structures and oxygen-containing group concentrations of the modified ACs were separately characterized and measured. Results showed that the use of oxygen plasma to modify the ACs made carbon surface oxygen-containing groups greatly increase, and thus significantly improved their adsorption capacities of DBT. More importantly, this novel modification method effectively keep the mass losses of the ACs to fell within a very narrow range of ±2%, which overcame a demerit of conventional thermal oxidation treatment which resulted in bad mass loss of 31.7–91.4%. The isotherms of DBT on the modified ACs were significantly higher than those on original AC. Fixed-bed breakthrough experiments showed that the working adsorption capacity of the modified ACs for DBT increased by 49.1% compared to the original AC.

► Oxygen plasma was used to modify activated carbon (AC) without mass loss of AC.
► Modification with oxygen plasma makes DBT adsorption capacity of AC increase greatly.
► Working capacity of modified AC for DBT increased by 49% compared to original AC.
► Isotherms of DBT on the modified ACs were best fitted by Langmuir model.