Simultaneous sulfur and nitrogen removal from fuel combining activated porous MIL-100(Fe) catalyst and sustainable solvents

Abstract

The high costs associated with commercially available desulfurization technologies in the refinery industry urge for the development of novel, highly efficient and sustainable alternative processes. On the other hand, the presence of nitrogen compounds significantly decreases the efficiency of the process. Therefore, effective alternative methodologies capable of removing simultaneously sulfur and nitrogen compounds from fuels under economic and sustainable procedures are desirable and needed for the petroleum industry. This work reports a sustainable catalytic process that conciliates oxidation and liquid-liquid extraction to efficiently remove sulfur and nitrogen from fuels. The effective catalytic oxidation was achieved by using a MIL-100(Fe)-based composite encapsulating the phosphomolybdic acid (PMo12) active center. Complete desulfurization of a multicomponent model fuel containing the most refractory sulfur and nitrogen compounds was achieved after only 30 min. Also, the nitrogen compounds were able to be removed after this short period, mainly by extraction using strategic solvents. The S/N removal process was faster when the expensive ionic liquid [BMIM]PF6 was replaced by the cost-effective ethanol. Furthermore, the catalyst could be reused in several consecutive desulfurization and denitrogenation cycles, as well as the ethanol extraction solvent was reused for at least four cycles without loss of efficiency.