Interactions of 4,6-Dimethyldibenzothiophene with the Surface of Activated Carbons

Two Carbon samples, commercial wood-based carbons and laboratory-derived polymer-based carbon, were oxidized to two different levels of surface acidity. The resulting adsorbents were characterized using adsorption of nitrogen, potentiometric titration, FTIR, SEM/EDAX, and elemental analysis. Oil the carbons obtained, the adsorption of 4,6-dimethyldibenzothiophene (4,6-DMDBT) from hexadecane was carried out in the range of the initial concentrations between 10 and 150 ppmw sulfur. The results indicate that pores with diameters less than 10 are important for adsorption of 4,6-DMDBT. Chemical transformations, likely oxidation, occur in larger pores, and (lie extent of this process is governed by the availability of oxidants. Those oxidants might be either chemisorbed oxygen and/or iron oxides present in an inorganic matter. Surface acidic groups, when located in larger pores, attract 4,6-DMDBT via specific interactions, and this can increase the amount adsorbed. When the density of these groups is high, they create obstacles for the effective packing of the adsorbate in the pore space and, thus, the amount adsorbed decreases.