Extraction combined oxidation desulfurization of dibenzothiophene using polyoxometalate-supported magnetic chitosan microspheres

• Published in: Journal of the Taiwan Institute of Chemical Engineers 2020-12, Vol.117, p.112-122
• Main Authors: Liu, Yefeng, Zuo, Peng, Wang, Fei, Lv, Ying, Wang, Ruixin, Jiao, Weizhou
• Format: Article
• Language: English
• Subjects: Immobilization; Liquid fuel; Magnetic chitosan microspheres; Oxidative desulfurization; Polyoxometalates
• ISSN: 1876-1070; 1876-1089
• DOI: 10.1016/j.jtice.2020.12.003

lThe strong loading of polyoxometalates (POMs) on cross-linked chitosan (CS)-modified Fe3O4@CS with a higher loading of 34.26 g/100 g.lFe3O4@CS@POM shows the good oxidative desulfurization performance of liquid fuels.lFe3O4@CS@POM has the good reusability.lFe3O4@CS@POM can be easily separated and recycled in the external magnetic field. In this study, Keggin- and Dawson-type polyoxometalates (POMs) were immobilized on chitosan (CS)-modified Fe3O4@CS by electrostatic interaction for the preparation of heterogeneous catalysts Fe3O4@CS@POM (POM=PMo12, PW12, SiW12, P2W17, or P2W18). The oxidative desulfurization (ODS) of dibenzothiophene (DBT) by Fe3O4@CS@POMs was evaluated. It is found that Fe3O4@CS@POM shows the good ODS performance due to the good dispersion of POM on Fe3O4 surface and the good accessibility of substrate to it leaded by the full swelling of the cross-linked CS in acetonitrile. The catalytic activity follows the order of Fe3O4@CS@PMo12 > Fe3O4@CS@PW12 > Fe3O4@CS@P2W17 > Fe3O4@CS@P2W18 > Fe3O4@CS@SiW12. At 333 K, the desulfurization rate of DBT (500 ppm) reaches 99.7% at 60 min and 100% at 90 min in the presence of 0.1 g of Fe3O4@CS@PMo12 and 100 µL of H2O2. The ODS process can be well described by the pseudo-first-order kinetic model (R2 > 0.99) with a high kinetic constant (0.0761 min−1) and a low apparent activation energy (60.57 kJ / mol). In addition, the as-prepared catalyst can be easily separated and recycled in the external magnetic field, and it still has the good reusability for several times, stemming from the stable encapsulation of POM clusters by cross-linked chitosan on Fe3O4 surface.