Preparation of melamine sponge decorated with silver nanoparticles-modified graphene for water disinfection

This paper reports the fabrication of melamine sponge decorated with silver nanoparticles-modified graphene (G/AgNPs-MS) for water disinfection. The G/AgNPs-MS composites with the high porosity and elasticity were used in an antibacterial process in which the composite was first immersed in bacterial suspension, and subsequently squeezed via hand compression. G/AgNPs-MS exhibited more excellent bactericidal activity against Escherichia coli and Staphylococcus aureus bacteria compared with melamine sponge (MS), melamine sponge decorated with graphene (G-MS), and melamine sponge decorated with silver nanoparticles (AgNPs-MS). The superior antibacterial effect was possibly ascribed to the coordination of graphene oxide (GO) and silver nanoparticles (Ag NPs). Compared to AgNPs-MS, G/AgNPs-MS displayed better stability with fewer Ag⁺ release. G/AgNPs-MS composites were highly reusable with no significant differences in the loss of bacterial viability over 12 operational cycles. The possible antibacterial mechanism of G/AgNPs-MS was also investigated. It was found that the destruction of bacterial membrane by G/AgNPs-MS played an important role in the bactericidal activity. The generation of intercellular ROS and scavenging assays confirmed the involvement of Ag⁺ and ROS in the antibacterial process of G/AgNPs-MS. All the results demonstrated that the prepared G/AgNPs-MS composites, as innovative antibacterial materials, showed a great potential for water disinfection.