Light-Enhanced Adsorptive Desulfurization of Dibenzothiophene Using Supported TiO2-ZrO2

Abstract

Combustion of diesel fuel containing sulfur compounds emits SOx into atmosphere causing acid rain and respiratory illness in human. Dibenzothiophene (DBT) is one of the most difficult sulfur compounds in diesel to be removed by hydrodesulfurization (HDS). To produce ultra-low sulfur diesel (<15 ppmw-S), severe operating condition is required. As a result, production cost is increase. In this work, we investigated an alternative method for sulfur removal called Light-enhanced Adsorptive Desulfurization or L-ADS using supported TiO2-ZrO2. The TiO2-ZrO2 was loaded on commercial γ-Al2O3, fumed silica (FS), silica gel (SG) and zeolite (Z30) by wet-impregnation method. Impact of these supports on DBT removal were focused. Characteristic of the supported TiO2-ZrO2 was analyzed by N2 adsorption-desorption, scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS), and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). The presence of TiO2-ZrO2 greatly enhanced DBT removal compared to TiO2 and ZrO2. SG promoted DBT removal by facilitating the adsorption of dibenzothiophene sulfone (DBTO2), a product of DBT photocatalytic oxidation. Using TiO2-ZrO2/SG, 86% of sulfur was removed from 50 ppmw-S DBT/C16 within 4 h.