Synthesis and bactericidal action of Fe3O4/AgO bifunctional magnetic-bactericidal nanocomposite

Abstract AgO-Fe 3 O 4 hybrid is a promising bactericidal agent for water purification, because of its strong antimicrobial activity and magnetically recoverable performance. However, the complicated preparing process, raw materials waste and milling medium contamination of AgO-Fe 3 O 4 hybrids have limited its practical application. In this paper, Fe 3 O 4 /AgO nanocomposite synthesized via a simple chemical oxidation method was investigated. The nanocomposite with 35.0 wt% AgO content was composed of monoclinic AgO and cubic Fe 3 O 4 . The nanocomposite exhibited strong antimicrobial properties, superparamagnetic behavior, good magnetically recoverable performance and bactericidal stability. When the concentration was 20 mg.L −1 , more than 98.5% of S. aureus or E. coli was killed in 25 min. Further increasing the concentration to 5000 mg.L −1 , all of the two bacteria were killed in 25 min. Finally, based on present investigation, a plausible bactericidal mode of action for the nanocomposite against S. aureus and E. coli was proposed.