Role of microporosity and surface chemistry in adsorption of 4,6-dimethyldibenzothiophene on polymer-derived activated carbons

Two carbon samples derived from poly(4-styrenesulfonic acid-co-maleic acid) based polymer by carbonization between 700 and 800 °C were oxidized to two different levels of surface acidity. The surfaces of resulting adsorbents were characterized by potentiometric titration, adsorption of nitrogen, FTIR, SEM/EDAX and thermal analysis. The materials were used as adsorbents of 4,6-dimethyldibenzothiophene (4,6-DMDBT) from hexadecane with initial concentration of sulfur between 10–150 ppmw. Although it was found that pores with diameter less than 10 Å govern the amount of 4,6-DMDBT adsorbed, that amount is enhanced when acidic groups are present in the larger pores owing to the contributions of specific interactions. Surface chemistry plays an important role in reactive adsorption and deposition of the products of surface reactions in the pore system.