— The catalytic oxidative desulfurization (Cat-ODS) process has been introduced as a new technology to achieve ultra-low sulphur levels in diesel fuels. In this study, the performance of the alumina supported iron oxide based catalysts doped with cobalt, synthesized via wet impregnation method on the Cat-ODS of the model diesel with the total sulphur 500ppm was investigated using tert-butyl hydroperoxide (TBHP) as an oxidizing agent and N,N-dimethylformamide as an extraction solvent. A series of dopant was being screened. Co/Fe-Al2O3 (10:90) and Co/Fe-Al2O3 (20:80) prepared at 400°C. Overall, the catalytic activity decreased as dopant ratio increased. Catalyst with 10 wt% of Co was successfully removed 96% of thiophene, 100% of DBT and 92% of 4,6-DMDBT in model diesel. Further investigation, potential catalyst that calcined at 400°C contributed higher sulphur removal compared to the catalyst calcined at 500°C. X-ray diffraction analysis (XRD) result showed that Co/Fe-Al2O3 (10:90) prepared at 400°C was amorphous, while micrograph of the field emission scanning electron microscopy (FESEM) illustrated an inhomogeneous distribution of various particle sizes. The energy dispersive X-ray analysis (EDX) result have confirmed the presence of Fe and Co in all of the prepared catalyst.

Hydrodesulfurization (HDS) technique is no longer applicable in achieving ultra-low sulfur diesel because of high operational cost, high operating temperature and low efficiency. Due to these disadvantage, catalytic oxidative desulfurization (Cat-ODS) has been introduced as a new technique in achieving ultra-low sulfur diesel. The performance of the Fe catalyst was investigated in Cat-ODS of model diesel using terbutyl hydroperoxide (TBHP) as oxidant and dimethylformamide (DMF) as an extracting solvent. The physicochemical analysis of this catalyst was accomplished using several characterization techniques such as BET, EDX and HRTEM. It posseses high surface area of 226 m2g-1 with small particle sizes in the range of 6-7 nm and less metal leaching. Under optimize condition, about 90% of sulfur was removed from model diesel. In the absence of catalyst, only about less than 80% of organosulfur compounds were removed. The Cat-ODS system showed the promising technology to be compliment with hydrodesulfurization (HDS) to produce low sulfur diesel.

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