Antimicrobial air filter made of chitosan-ZnO nanoparticles immobilized on white silica gel beads

Abstract

Airborne disease transmitted by biological air pollution threatens public space, therefore developing antimicrobial air filters is a crucial study. This study investigated the environmentally friendly preparation of synthetic zinc oxide nanoparticles (ZnOnano-synth) at ambient temperature and the ZnO immobilization technique on silica gel beads coated with chitosan. The immobilized ZnO was used as an air filter in the simulated air chamber. Methanol swelled the 4.59 ± 0.5 wt% of the chitosan layer causing ZnO particles to stick to it, being stabilized, and dispersed. The dispersed ZnO particles of 5.18 ± 1.70 nm, thereby the efficacy preparation procedure is confirmed. The ZnOnano-synth exhibited high antibacterial properties against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria in agar media with inhibition diameters up to (33.50 ± 0.10 mm). Air filters containing the ZnOnano-synth-chi-SiG exhibited high and prolonged antibacterial activity against Bacillus subtilis in the air with 92% efficacy. These synthetic ZnO nanoparticles show better characteristics than commercial ZnO nanoparticles in terms of the particle size and the antibacterial properties of Staphylococcus aureus and Escherichia coli.