Antibacterial Melamine Foams Decorated with <i>in Situ</i> Synthesized Silver Nanoparticles

Abstract

A new\nand straightforward single-step route to decorate melamine foams with\nsilver nanoparticles (ME/Ag) is proposed. Uniform coatings of silver\nnanoparticles with diameters less than 10 nm are formed <i>in\nsitu</i> directly on the struts surface of the foams, after their\ndipping in an AgNO₃ solution. We prove that the nanoparticles\nare stably adhered on the foams, and that their amount can be directly\ncontrolled by the concentration of the AgNO₃ solution and\nthe dipping time. Following this production route, ME/Ag foams can\nbe obtained with silver content ranging between 0.2 and 18.6 wt %\nand excellent antibacterial performance, making them appropriate for\nvarious applications. Herein we explore the possibility to use them\nas antibacterial filters for water treatment, proving that they are\nable to remove completely <i>Escherichia coli</i> bacteria\nfrom water when filtered at flow rates up to 100 mL/h·cm² due to the release of less than 1 ppm of Ag⁺ ions\nby the foams. No bacterial regrowth was observed after further dilution\nof the treated water, to arrive below the safety threshold of Ag⁺ for drinking water (0.1 ppm), demonstrating the excellent\nbactericide performance of the ME/Ag filters.