LAUSR

Abstract An antibacterial composite material based on the incorporation of diatomite (DE), graphene oxide (GO), and silver nanoparticles (AgNPs) was developed. It can significantly increase the antibacterial capability of DE and separation efficiency of GO and AgNPs. GO improves the stability of AgNPs and reduces the loss of Ag(AgNPs/GO/DE) on composites. The Ag content of the AgNP/GO/DE composite was determined by inductively coupled plasma-mass spectrometry (ICP-MS) to be 2340 ppm. The as-prepared AgNPs/GO/DE demonstrated excellent antibacterial properties to E. coli and S. aureus, evaluated by measuring the minimum bactericidal concentration (MBC) using twofold serial dilutions in a lysogeny broth medium. The MBC of AgNPs/GO/DE against E. coli and S. aureus were 5 and 10 mg/mL, respectively. The amount of silver released into the water was 38–46 ppb. Fluorescence staining and SEM results indicated that the bacteria were adsorbed on AgNPs/GO/DE and killed. AgNPs/GO/DE showed a stronger antibacterial effect on E. coli than S. aureus, which was related to the cell wall structure of the bacteria.