Green synthesis of chitosan-stabilized silver-colloidal nanoparticles immobilized on white-silica-gel beads and the antibacterial activities in a simulated-air-filter

This study explored the green synthesis and immobilization of colloidal silver nanopar-ticles (AgNPs) on a solid compatible support. Its antibacterial properties in reusable air filters are also discussed. The chitosan stabilized colloidal AgNPs (chi-AgNPs) were prepared using visible light irradiation in methanol. The UV-Vis, FTIR spectra, and TEM confirmed the chi-AgNPs for-mation. The immobilization technique of chi-AgNPs on the surface of white-silica-gel beads, which was previously coated chitosan (chi-SiG), was effective. The immobilized silver particles (AgNPs-[chi-SiG]) were solid, stable, dispersed, and nano-size. Both AgNPs-[chi-SiG] and chi-SiG exhibited antibacterial properties and prevented the growth of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria in agar media. Air filter containing the AgNPs-[chi-SiG] showed high antibacterial activity against Bacillus subtilis in the air. (c) 2021 The Authors. Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).