Photooxidative-extractive deep desulfurization of diesel using Cu-Fe/TiO2 and eutectic ionic liquid

An efficient photooxidative-extractive system for deep desulfurization of model fuel and actual diesel fuel was explored. A series of bimetallic Cu-Fe/TiO2 photocatalysts was synthesized using sol-gel hydrothermal method and characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray analysis (EDX), high resolution transmission electron microscopy (HRTEM) and diffuse reflectance UV-visible spectroscopy (DR-UV-Vis). The photocatalysts were evaluated for photooxidative-extractive deep desulfurization of model oil (100, 300 and 500 ppm dibenzothiophene in dodecane) and actual diesel fuel. 2.0 wt% Cu-Fe/TiO2 photocatalyst was identified as the most efficient photocatalyst for the conversion of sulfur species under mild conditions in the presence of hydrogen peroxide (H2O2: S molar ratio of 4) as oxidant and eutectic based ionic liquid as extractant. The sulfur conversion in both model oil and actual diesel fuel reached 100%. The removal of sulfur species from both model oil and actual diesel fuel was done by two times extraction with a removal of 97.06% and 78.93%, respectively in the first run and 2.94% and 21.07%, respectively in the second run. The photocatalyst was able to be recycled for six cycles with an average performance of 99.75%. (C) 2015 Elsevier Ltd. All rights reserved.