A polyoxometalate-modified magnetic nanocomposite: a promising antibacterial material for water treatment.

In this work, polyoxometalate-modified magnetic nanocomposite Fe3O4@PDA@POM was prepared by coating [Cu(HL)4]2[P2Mo5O23]2·8H2O (POM, L = 2-aminopyridine) on the surface of a preassembled polydopamine (PDA)-capped carboxyl-functionalized Fe3O4 magnetic microspheres. Our studies on Gram negative bacterium Escherichia coli (E. coli) indicated that owing to the collective effect between preassembled Fe3O4 and POM, the Fe3O4@PDA@POM nanocomposite loaded on nickel foam exhibited outstanding antibacterial activity and reusability, and even after 6 cycles it has a high antibacterial capability of ca. 90%. Further extension of this investigation towards Gram positive bacterium Staphylococcus albus (S. aureus) demonstrated a similar toxicity pattern, confirming the potential applications of this material for water treatment in biochemical processes. The antibacterial mechanism of the Fe3O4@PDA@POM nanocomposite was further investigated by taking E. coli as a model microorganism.