Synthesis, Characterization and Performance Evaluation of Pure Silica MCM-41 for Effective Removal of Dibenzothiophene from Petroleum Distillate

Abstract

The presence of sulfur-containing compound (e.g. Dibenzothiophene, DBT) in petroleum distillates such as diesel is of great concern due to the environmental problems it poses on the environment. In this study, synthesis and performance evaluation of MCM-41 adsorbent for enhanced removal of DBT from petroleum distillates in batch adsorption mode is reported. MCM-41, employed in this study for adsorptive desulphurization, was successfully synthesized with Cetyltrimethylammonium bromide (C19H42BrN) and fumed silica (SiO2). The gel was stirred for 30 min at room temperature and allowed to age at varied durations ( 24 h, 48 h & 72 h) before hydrothermal synthesis and then calcined at 550 C. Different analytical techniques were used to characterize the synthesized adsorbents, such as; Fourier transform infrared (FTIR) to check the surface nature, N2 physi-sorption at 77 K to examine the textural property; Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) equipped with Energy Dispersive X-ray (EDX) to check the surface morphology/elemental composition; and X-ray diffraction (XRD) to check the crystallinity of the adsorbent. The adsorptive desulphurization experiments were carried out using a model diesel prepared by dissolving 0.1 g of dibenzothiophene in 100 mL of hexane. The desulfurized model diesel was analyzed using Gas Chromatography/Mass Spectrometer (GC/MS). The adsorption performance of each adsorbent was evaluated in a batch mode. The results showed that, aging time has significant impact on the crystallinity and textural properties of MCM-41. The results show that crystallinity increased with decreasing aging period with smaller surface area as compared to adsorbent whose gel was aged for more hours. Furthermore, the textural properties seem to improve as the aging time increased. MCM-41, whose gel was aged for 72 h showed the highest adsorption capacity of 36.2 mg/g with highest DBT removal of 96.5 %. The information and results presented in this study could therefore provide a platform for further studies in this field.