High-Efficiency\nBroad-Spectrum Antibacterial Activity\nof Chitosan/Zinc Ion/Polyoxometalate Composite Films for Water Treatment

The\ndevelopment of multifunctional films with rapidly\nkilling microorganisms\nand adsorbing residual antibiotics in wastewater remains a challenging\nendeavor. In this work, the chitosan/zinc ion/polyoxometalate (CS/Zn<sup>2+</sup>/POM) multifunctional films were prepared by the freeze-drying\nmethod using chitosan, ZnO, and POM. Notably, the CS/Zn<sup>2+</sup>/POM films exhibited excellent bactericidal properties against Gram-positive/negative\nbacterial strains including Staphylococcus aureus (S. aureus, 99.80%), Escherichia coli (E. coli, 99.82%), and drug-resistant E. coli bacterial strains (kanamycin-resistant E. coli, 87.76% and ampicillin-resistant E. coli, 99.71%). This may be due to the chelation of Zn<sup>2+</sup> with\nCS disrupting the cell membrane and bringing POM into direct contact\nwith bacteria, leading to bacterial death. In addition, the CS/Zn<sup>2+</sup>/POM films showed good adsorption performance to a tetracycline\n(TC) solution (adsorption rate 75.2%). Further studies showed that\nthe main process of tetracycline removal by CS/Zn<sup>2+</sup>/POM\nfilms was controlled by a physical adsorption. This POM-based film\nmaterial has an important potential for the synthesis of broad-spectrum\nantimicrobial materials for the removal of residual antibiotics from\nwater pollutants such as tetracycline.