Investigation of the enhancing effects of sulfur and/or oxygen functional groups of nanoporous carbons on adsorption of dibenzothiophenes

Adsorption of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from simulated diesel fuel with 20 ppmw total concentration of sulfur was investigated on polymer-derived carbon containing various amounts of oxygen and sulfur incorporated to the surface. Initial and exhausted carbons were characterized using adsorption of nitrogen, thermal analysis, potentiometric titration, XPS, mass spectroscopy and elemental analysis. Selectivities for DBT and DMDBT adsorption were calculated with reference to naphthalene. It was found that both the capacity and selectivity for DBT and DMDBT removal from model diesel fuel were affected by the content and arrangement of heteroatoms. Although both oxygen and sulfur containing groups enhance the capacity, the enhancing effects of surface chemistry were more pronounced on the carbon with sulfur incorporated to its matrix. This is linked to sulfur–sulfur interactions.