Mesoporous catalyst based on niobium for oxidative desulfurization and denitrogenation of fuels: PET as a valuable feedstock

Abstract This work reports the catalytic activity of a mesoporous material prepared from terephthalic acid obtained via alkaline hydrolysis of recycled polyethylene terephthalate (PET) bottles and niobium salt. PET, commonly found in household waste, is an inexpensive source of terephthalic acid. The synthetic protocol and characterization of the material are thoroughly described. Powder X-ray diffraction (PXRD) confirmed the formation of a crystalline phase, with an average crystallite size of 2.57 µm. Fourier transform infrared spectroscopy (FTIR) and elemental analysis (CHN) confirmed the formation of a new compound with irregular morphology, as observed by scanning electron microscopy (SEM). The structural and electronic properties of the proposed catalyst were further investigated using density functional theory (DFT). Nitrogen adsorption–desorption analysis revealed a type IV isotherm, typical of mesoporous materials. The catalyst was applied in oxidation reactions for the removal of model sulfur- and nitrogen-containing petroleum contaminants. The conditions were optimized, yielding removal efficiencies of 90% for dibenzothiophene and 86% for quinoline, which are suitable models for sulfur- and nitrogen-containing compounds, respectively.