For manufacturing of clean gasoline with a lower S content (e.g., S <10 ppm), glycine-modified polyoxotungstate ((gly) 3 H[SiW 12 O 40 ]) was immobilized on cobalt ferrite (CoFe 2 O 4 ) nanoceramics via the sol−gel method and employed as an efficient recyclable nanocatalyst in an extractive−oxidative desulfurization (EODS) system. The synthesized (gly) 3 H-[SiW 12 O 40 ]⊂CoFe 2 O 4 nanocatalyst was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) techniques. The optimum conditions for the reaction are given as follows: 50 mL of model and real gasoline, 0.10 g of (gly) 3 H[SiW 12 O 40 ]⊂CoFe 2 O 4 nanocatalyst, 60 min reaction time, 35 °C reaction temperature, 3 mL of AcOH/ H 2 O 2 (V/V ratio of 1:2) as an oxidant system, and 10 mL of CH 3 CN solvent as an extractant. Based on optimization results under the mentioned conditions and the proposed EODS system, the removal efficiency (%) of the model fuel utilizing the (gly) 3 H[SiW 12 O 40 ]⊂CoFe 2 O 4 nanocatalyst can reach 98% with stable reusability up to five times without a noticeable decrease in its catalytic activity. Correspondingly, 0.4986 ppm S content in real gasoline could decline to 0.0145 ppm with a removal yield of 96% under identical conditions. Also, the kinetics of the EODS reactions was found to be pseudo-first order, and the EODS mechanism was put forward through the generation of a peroxometalate intermediate complex with phase transfer properties. The present research shows that liquid fuels can be purified into ultralow-sulfur fuels through highly oxidative desulfurization via the (gly) 3 H[SiW 12 O 40 ]⊂CoFe 2 O 4 nanocatalyst after the EODS process.

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From the environmental protection and human health perspectives, the design and synthesis of efficient and reusable oxidative desulfurization nanocatalysts has always been sought after by scientists and industries. In this regard, a new heterogeneous nanocatalyst (V-SPM@PANI@CH) was synthesized by immobilizing Keggin-type vanadium-substituted phosphomolybdate ([PVMo 11 O 39 ] 4− ) (named V-SPM) clusters on the surface of polyaniline (PANI) and chitosan (CH) polymers. The features of the assembled nanocatalyst were detected by Fourier transform infrared spectroscopy, ultraviolet−visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive X-ray spectroscopy techniques in detail. The XRD studies indicated that the average crystallite size of V-SPM@ PANI@CH was estimated to be about 36 nm. The catalytic performance of V-SPM@PANI@CH was investigated in the extractive and catalytic oxidation desulfurization (ECOD) procedure of real and thiophenic model gasoline by H 2 O 2 /AcOH (volume proportion of 2:1) as an oxidizing system. The optimal desulfurization conditions for ECOD reactions were as follows: 50 mL of model/real gasoline, 0.1 g of V-SPM@PANI@CH, reaction time of 60 min, and reaction temperature of 35 °C. Under the experimental conditions outlined above and the designed ECOD system, the content of sulfur in real gasoline could decline from 0.4985 to 0.0193 wt %, which corresponds to an efficiency of 96%. Moreover, the removal percentage of aromatic hydrocarbons, including thiophene (Th), benzothiophene (BT), and di-benzothiophene (DBT) as model fuels decreases in the order of DBT ≥ BT > Th under identical operating conditions. High catalytic activity was maintained with only a slight loss during five cycles. This work offers the ECOD system (V-SPM@PANI@CH/AcOH/H 2 O 2 ) for the desulfurization of liquid fuels, which had a great repercussion on the ECOD efficiency.

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