Polydopamine/silver hybrid coatings on soda-lime glass spheres with controllable release ability for inhibiting biofilm formation

Abstract

Filtering media is anything placed in a filter that changes the quality of water flowing through it. With the variety of media available, proper selection of filter media is of great importance for filter performance. Recycled glass is evaluated as an alternative to silica sand in media filters and is an effective medium with the advantages of lower cost than silica sand, more environmental friendliness as it is a recycled product, and ease to pulverize into different sizes for specific design requirements. However, the filtration efficiency of regenerated recycled glass is limited by the formation of biofilms on its surfaces due to the large number of microorganisms such as bacteria and algae existing in the water. In this study, hydrofluoric (HF) acid etched glass spheres (GSs) modified with polydopamine (PDA) and silver nanoparticles (PDA-Ag-HF/GSs) were fabricated on the surface of soda-lime GSs by HF etching, crystal in situ growth, and PDA coating. HF etching and the modification of PDA coating imparted good hydrophilicity to PDA-Ag-HF/GSs. The modification of the silver coating also rendered PDA-Ag-HF/GSs excellent antibacterial properties and reduced Chlorella adhesion, and inhibited microorganism growth ability by releasing Ag+. The catechol functional group on the PDA coating could regulate the Ag+ release by chelation. Good antibacterial properties, anti-algae adhesion, and controlled release of Ag+ indicate that PDA-Ag-HF/GS coating can effectively inhibit the formation of biofilm on the surface of the material, providing a new strategy for the formation of anti-biofilm.