Synergy between Copper and Silver Nanoparticles for the Removal of Thiophenic Compounds in Fuel Oil

Thiophenic compounds in fuel oils lead to the emission of SO_x pollutants. Zero-valence Cu and Ag particles were supported on carbonized cellulose via reduction reactions. Only Cu(0) and Ag(0) microcrystals with sizes of 4–15 nm and 10–30 nm had high thiophene adsorption capacity. The growth of Cu crystals was inhibited by Ag⁺, whereas the dispersion and loading of Ag were promoted by Cu²⁺. The removal rates for thiophenic compounds in high-sulfur content oil reached 35.3–54.3 %. The steric hindrance of substituent groups had a negative impact on the desulfurization effect. The thiophene adsorption capacity reached 8.7 mg sulfur/g. This thiophene adsorption process agreed with Elovich and second-order kinetics as well as Langmuir and Freundlich models, implying that a monolayer of thiophene was adsorbed on a heterogeneous surface via chemisorption. The coordination interactions between sulfur and metals dominated the adsorption process.