سنتز و شناسايي چارچوب فلز-آلي MIL-101 اصلاح شده با پلي‌اكسووانادات (POV) و بررسي فعاليت كاتاليستي آن در فرآيندهاي گوگردزدايي اكسايشي

Synthesis an‎d Characterization of MIL-101 Metal-Organic Framework Modified with Polyoxovanadate (POV) an‎d Investigation of Its Catalytic Activity in Oxidative Desulfurization Processes

شيمي معدني

The design of heterogeneous catalysts with high performance, chemical stability, an‎d recyclability represents one of the key challenges in developing clean an‎d efficient processes for fossil fuel purification. In this context, the present study focuses on the synthesis an‎d eva‎luation of a novel catalytic nanocomposite with the structure SV2W10@MIL-101(Fe)-NH2, which has been designed an‎d fabricated for the first time with the aim of optimizing the oxidative desulfurization (ODS) process. This nanocatalyst was constructed by encapsulating vanadium-containing polyoxometalate [SV2W10O40]4- (SV2W10) within the amino-functionalized metal–organic framework MIL-101(Fe)-NH2, thereby combining the outstan‎ding properties of both components namely, high redox activity, large surface area, structural stability, an‎d facile accessibility of active sites into a hybrid platform. The catalytic performance of the synthesized material was systematically eva‎luated an‎d optimized for the removal of dibenzothiophene (DBT) an‎d benzothiophene (BT) from a model fuel (n-octane). Key reaction parameters, including polyoxometalate loading, catalyst dosage, H2O2/DBT ratio, temperature, an‎d reaction time, were thoroughly investigated, revealing the role of each parameter in enhancing process efficiency. Under optimal conditions, results demonstrated that in the presence of 25 mg of SV2W10@MIL-101(Fe)-NH2(3), acetonitrile as the extractive solvent, an‎d H2O2 as the oxidant, the DBT conversion reached over 99% at 50 °C within 1 h. In contrast, the lower conversion of BT highlighted the selec‎tive nature of the synthesized structure toward bulkier sulfur-containing compounds. This finding underscores the rational an‎d effective molecular-level design of the catalyst. Comprehensive characterization of the nanocomposite was conducted using FTIR, Raman, PXRD, TEM, FE-SEM, MAP, EDX, ICP-OES, BET, an‎d TGA techniques, confirming the structural integrity, successful incorporation of polyoxometalate, favorable morphology, high thermal stability, an‎d large accessible surface area. Furthermore, the recyclability of SV2W10@MIL-101(Fe)-NH2 was examined as an efficient heterogeneous catalyst with easy separation from the reaction medium. Notably, it maintained catalytic activity with negligible polyoxometalate leaching in the nanocatalyst after seven successive cycles. Overall, this nanocomposite represents an innovative catalytic platform with exceptional performance, high recyclability, an‎d promising industrial potential, marking a significant step toward the advancement of novel desulfurization technologies an‎d green fuel refining.

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