Effect of pore structure and oxygen-containing groups on adsorption of dibenzothiophene over activated carbon

Activated carbons chemically treated by steam and concentrated H2SO4, were used as adsorbents for removing organic sulfur compounds from a model diesel. The modified activated carbon was characterized by N2 sorption, base titration and FTIR spectroscopy. As compared with the untreated activated carbon, the treatment by a steam at 900 °C increased the mesoporous volumes from 0.248 to 0.856 cm3/g and sulfur adsorption capacity for dibenzothiophene from 10.9 to 20.6 mg/g and the treatment by a concentrated H2SO4 at 250 °C increased the amount of surface acidic-oxygenated groups from 0.05 to 1.95 mmol/g, and total adsorption capacity for dibenzothiophene from 10.9 to 33.3 mg/g. The total adsorption capacity for dibenzothiophene is found to be proportional to the mesoporous volume and the amount of surface oxygen-containing groups. It is proposed that direct interaction between the sulfur atom and surface oxygen-containing groups plays an important role in the adsorption of organic sulfur compound.

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