Ultra-deep desulfurization of fuel with metal complex of Chitosan Schiff Base assisted by ultraviolet

Ultraviolet-assisted oxidative desulfurization (UODS) was applied to diesel, gasoline and petroleum product feedstock containing model sulfur compounds (thiophene, thiotolene, thioxene and benzothiophene). The influence of oxidant amount, volume of acetonitrile, reaction time and temperature on the sulfur removal efficiency from model sulfur compounds and real oils in the presence of ultraviolet was investigated in the presence of ultraviolet. By using the optimized conditions for UODS, desulfurization rates of thiophene and benzothiophene increased to 98.87% and 99.87%, respectively, and desulfurization rates of thiotolene and thioxene to 96.86% and 98.37%, respectively, which were achieved for model compounds in petroleum product feedstock. By using the same conditions, the removal of sulfur for real gasoline and diesel samples was 98.34% and 97.17%, respectively. For model compounds, real gasoline and diesel samples, sulfur removal without ultraviolet and on the same conditions was lower than that with ultraviolet, which shows that ultraviolet improved the efficiency of oxidative desulfurization. The results for sulfur removal from gasoline and diesel samples prove the feasibility of the proposed UODS procedure for sulfur removal from real oil samples. (C) 2011 Elsevier Ltd. All rights reserved.