Keywords: Desulfurization; adsorption; activated carbon; isotherms; kinetics

Abstract

The purpose of this study was to identify the effect of modified activated carbon (MAC) on the adsorption isotherms and kinetics of dibenzothiophene (DBT) removal in a model fuel. In this study the commercial activated carbon (AC) was modified by chemical treatment with nitric acid (HNO3) followed by adsorption experiments with different concentrations and contact times. The MAC was characterized using Fourier-transform infrared spectroscopy (FTIR) to identify changes in the MAC functional groups. A broad and intense peak at 3471.53 cm-1 for MAC was detected which indicates the stretching vibration of the O–H bond. After adsorption, the solution was analysed using ultraviolet-visible (UV-vis) light spectroscopy. In this study, the amount of DBT adsorbed by the MAC was in the range of 46.8% to 68.3%. Equilibrium isotherm data were analyzed according to Langmuir and Freundlich isotherm models. Pseudo first-order and pseudo second-order kinetic models were used to test the adsorption kinetics. The adsorption capacity and the rate of adsorption for DBT was found to be 1.54 mg/g and 0.74, respectively. Kinetic studies indicated that the sorption of DBT followed the pseudo first-order kinetic model with a correlation coefficient of 0.9912.