Exploring the impact of competitive compounds and catalyst synthesis method in DBT oxidative desulfurization using MoO3-V2O5/Al2O3 catalyst.

ABSTRACT

This research endeavors to address the pressing challenge of reducing sulfur content in fuels, an environmental imperative. It does so by employing bimetallic catalysts to enhance the efficiency of oxidative desulfurization (ODS) processes. This involves utilizing successive impregnation and co-impregnation methods to prepare a MoO3-V2O5/Al2O3. The catalysts underwent characterization using various techniques including X-ray diffraction (XRD), N2 adsorption-desorption, UV-vis (DRS), temperature-programmed desorption (NH3-TPD), Raman, Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and energy dispersive spectrum (EDS). The catalyst was utilized for the evaluation of the ODS process of dibenzothiophene (DBT). The effects of oxidants, namely H2O2 and t-butyl hydroperoxide (TBHP), were studied in the ODS. The catalyst prepared using the co-impregnation method (5M-15V-co) demonstrated significant acidic sites and exhibited remarkable efficiency in oxidative desulfurization. Remarkably, this catalyst achieved 100% oxidation of sulfur components within 30 min (min). To assess the catalyst's performance further, competitive compounds including nitrogen-containing compounds (NCCs) and saturated and unsaturated hydrocarbon compounds (HCs) were employed in the ODS. Initially, the introduction of NCCs led to a decrease in the sulfur removal rate; however, the catalyst successfully oxidized DBT completely within 60 min. When cyclohexene was present as an olefinic hydrocarbon compound, the catalyst oxidized DBT by approximately 75%, whereas DBT oxidation reached 100% within 20 min when p-xylene was introduced to the catalytic reactor. Additionally, as the O/S ratio increased from 2/5 to 10, the sulfur removal rate improved from 30 to 90%, indicating that HCs and NCCs compete with sulfur in terms of oxidant consumption.