Oxidative Desulfurization of Model Fuels over a Magnetic Kaolin-Supported MgO/Phosphomolybdic Acid Nanocomposite: Synthesis, Characterization, and Performance Evaluation

Sulfur-containing compounds in fossil fuels, particularly refractory aromatic species such as dibenzothiophene (DBT), are major contributors to sulfur oxide emissions and can also accelerate equipment corrosion and impair catalyst performance. In this study, a heterogeneous nanocomposite catalyst composed of magnesium oxide, magnetic kaolin, and phosphomolybdic acid polyoxometalate (H۳PM۰۱۲O۴۰) was developed and evaluated for the oxidative desulfurization of a model fuel. The catalyst was synthesized through a multistep procedure and comprehensively characterized using FT-IR, XRD, FE-SEM, EDS, TGA, and VSM analyses. The characterization results confirmed the successful formation of the composite structure, effective incorporation of the constituent phases, satisfactory thermal stability, favorable morphological features, and sufficient magnetic responsiveness for facile catalyst recovery. The catalytic performance was subsequently investigated as a function of several operational parameters, including the initial sulfur-compound concentration, reaction temperature, reaction time, catalyst dosage, and oxidant-to-DBT molar ratio. The synthesized nanocomposite exhibited effective catalytic activity toward the oxidation of sulfur-containing species, with DBT being readily converted into the corresponding polar sulfoxide and sulfone derivatives under relatively mild reaction conditions. In addition, the magnetic character of the support enabled straightforward separation of the catalyst from the reaction medium and facilitated its reuse. The preservation of catalytic activity over successive reaction cycles further demonstrated the structural and operational stability of the system, highlighting the potential of this magnetic polyoxometalate-based nanocomposite as a recyclable heterogeneous catalyst for oxidative desulfurization applications.

کلیدواژه ها:

Oxidative desulfurization (ODS) ، Dibenzothiophene (DBT) ، Magnetic kaolin ، Magnesium oxide ، Polyoxometalate ، Phosphomolybdic acid ، Heterogeneous catalysis ، Model fuel ، Recyclable catalyst