Synthesis of iron oxide nanoparticles modified mesoporous carbon and investigation of its application for removing dibenzothiophene from fuel model

In this study, magnetic ordered mesoporous carbon (γ-Fe2O3/CMK-3) containing iron oxide nanoparticles embedded in the carbon walls by wet impregnation method was prepared and used as a high effective magnetic adsorbent to adsorb polyaromatic sulfur compound (dibenzothiophene). The structure and morphology of adsorbent were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption-desorption (BET), thermal gravimetric (TGA) and alternating gradient force magnetometer techniques (AGFM). These techniques illustrate that the maghemite nanoparticles have an average size of 10 ± 3 nm and are well distributed on the ordered mesoporous carbon host. After embedding maghemite nanoparticles, the uniformity of mesoporous framework of CMK-3 still remaining stable, which has an ordered two-dimensional hexagonal (p6mm) structure, high specific surface area, maxima pore size of 5.5 nm and large pore volume (up to 1.01 cm3 g−1). The γ-Fe2O3/CMK-3 nanocomposite shows superparamagnetic behavior with a saturation magnetization of 0.5 emu g−1, which makes it favorable compound for magnetic separation procedure. The resulting magnetic mesoporous nanocomposite was investigated for adsorption of dibenzothiophene (DBT) as a model sulfur compound in n-hexane as fuel model. Various factors influencing the adsorption of DBT, including adsorption temperature, contact time and initial DBT concentration were studied. The kinetic data was well described by pseudo-second-order kinetic model and the equilibrium adsorption data was fitted to the Langmuir thermodynamic model. In addition, the adsorbent could be regenerated by washing with toluene and over 85% adsorption capacity could be maintained after three regeneration cycles. The results confirmed that γ-Fe2O3/CMK-3 has the potential superiority in removal of DBT from fuel model with a maximum adsorption capacity of 67 mg DBT per gram of adsorbent and an easy magnetically separable process.