Desulfurization of Fuel by Extraction and Catalytic Oxidation Using a Vanadium Substituted Dawson-Type Emulsion Catalyst

A vanadium-substituted Dawson-type polyoxometalate [cetronium]11P2W13V5O62 was fabricated to use in the extractive–catalytic oxidative desulfurization (ECODS) of fuels using hydrogen peroxide and ionic liquids (ILs), ethylene glycol, and a deep eutectic solvent. Taguchi robust was utilized to investigate the effects of operation parameters including H2O2 dosage, type of solvent, solvent-to-oil volume ratio, temperature, and contact time. The results demonstrated that the highest level of desulfurization could be achieved using a volume ratio of IL to oil = 1:6, O/(S + N) mole ratio = 4, and temperature = 70 °C after 45 min. The combination of the extraction and catalytic oxidation process showed that the step-by-step system (extraction in series with ECODS) was much better than the one-pot system (ECODS in one pot), which can remove 90% sulfur from 500 ppmw fuel and 87% sulfur from 1500 ppmw fuel under optimized conditions. The best system could also be reused 7 times in a 500 ppmw model fuel desulfurization and 4 times in a 1500 ppmw model fuel desulfurization.