Removal of Dibenzothiophene Using Activated Carbon/γ-Fe2O3 Nano-Composite: Kinetic and Thermodynamic Investigation of the Removal Process

Abstract

In the present study, removal of dibenzothiophene (DBT) from model oil (n-hexane) was investigated using magnetic activated carbon (MAC) nano-composite adsorbent. The synthesized nano-composite was characterized by FT-IR, FE-SEM, BET and VSM techniques. The MAC nano-composite exhibited a nearly superparamagnetic property with a saturation magnetization (M_s) of 29.2 emu g^-1, which made it desirable for separation under an external magnetic field. The magnetic adsorbent afforded a maximum adsorption capacity of 38.0 mg DBT g^-1 at the optimized conditions (adsorbent dose, 8 g l^-1; contact time, 1 h; temperature, 25 °C). Langmuir, Freundlich and Temkin isotherm models were used to fit equilibrium data for MAC nano-composite. Adsorption process could be well described by the Langmuir model. Kinetic studies were carried out and showed the sorption kinetics of DBT was best described by a pseudo-second-order kinetic model. In addition, the MAC nano-composite exhibited good capability of recycling to adsorb DBT in gasoline deep desulfurization.