Abstract:
Firstly, Fe
3O
4 nanospheres were prepared by solvothermal method, which were used as magnetic cores and coated with chitosan (CS) crosslinked by glutaraldehyde. Then, polyoxometalate (POM) was supported onto the magnetic CS carriers by electrostatic bonding and three magnetic polyoxometalates microspheres (Fe
3O
4@CS@POM) were prepared, including Keggin type magnetic phosphotungstic acid (Fe
3O
4@CS@PW
12) and Dawson type magnetic phosphotungstic acid (Fe
3O
4@CS@P
2W
17 and Fe
3O
4@CS@P
2W
18). Their structures and morphologies were characterized by FT-IR、UV-Vis、EA and TEM. The catalytic activity of Fe
3O
4@CS@POM on tetrahydrothiophene (THT) was investigated in detail. It is shown that all the three kinds of Fe
3O
4@CS@POM microspheres have good catalytic oxidation abilities to THT, among which Fe
3O
4@CS@PW
12 shows the best catalytic activity. The conversion of THT could reach 100% at room temperature after 105 min with a small amount of Fe
3O
4@CS@PW
12 (0.01 g). The catalytic oxidation process follows the quasi-first order kinetic model. The catalyst could be separated quickly and efficiently in the external magnetic field. In addition, Fe
3O
4@CS@PW
12 has good reusability, and the catalytic activity remains stable after 5 cycles.