چكيده به لاتين
Sulfur-containing compounds in fossil fuels pose a significant environmental challenge and a serious threat to public health worldwide. The combustion of these compounds releases sulfur dioxide (SO₂), which exacerbates respiratory and cardiovascular diseases, increasing the risk of premature mortality. According to the World Health Organization, over 7 million people worldwide die annually due to air pollution, with a significant portion attributed to sulfur-containing pollutants. Consequently, reducing sulfur compounds in fuels has become a critical necessity, attracting global scientific attention.
Among various desulfurization methods, Catalytic Oxidative Desulfurization (CODS) has gained prominence due to its high efficiency, mild operational conditions, and environmental compatibility. Catalysts such as heteropoly anions, metal oxides, and metal nanoparticles have been widely employed in this process. Among these, polyoxometalates (POMs) have emerged as highly effective catalysts. However, their limited surface area and high solubility present significant challenges. To overcome these drawbacks, POMs are often immobilized on various supports, including metal-organic frameworks (MOFs), to enhance their surface area, stability, and catalytic efficiency in oxidative desulfurization.
In this study, a modified polyoxometalate-based nanocatalyst immobilized on UiO-66 was synthesized and evaluated for oxidative desulfurization (ODS) of both real and model fuels, targeting the removal of thiophene (TH), benzothiophene (BT), and dibenzothiophene (DBT). The final nanocomposite structure was characterized using FT-IR, XRD, EDS, Mapping, FE-SEM, and BET analyses, confirming its successful synthesis and structural integrity.
The catalytic performance of the synthesized material was assessed under optimal conditions, where 0.08 g of the catalyst at 40°C, in 30 minutes, and in the presence of 1.5 mL of oxidant with a 1:1 molar ratio (H₂O₂/HCO₂H) achieved 97% desulfurization efficiency for DBT at 1000 ppm concentration in the model fuel.
Performance evaluation demonstrated that the catalyst followed the efficiency order of DBT > BT > TH in sulfur removal. Additionally, the catalyst exhibited remarkable reusability, maintaining high efficiency over five consecutive cycles without significant loss of activity.
Due to its environmental compatibility and high efficiency, this approach represents a promising and sustainable strategy for the removal of sulfur contaminants from fuels. This research contributes to developing innovative solutions for mitigating sulfur-related environmental pollution and enhancing the quality of fossil fuels.
