title: Visible-light-driven photocatalytic inactivation of Escherichia coli by magnetic Fe2O3-AgBr.
abstract: Bacterial inactivation by magnetic photocatalyst receives increasing interests for the ease recovery and reuse of photocatalysts. This study investigated bacterial inactivation by a magnetic photocatalysts, Fe2O3-AgBr, under the irradiation of a commercially available light emitting diode lamp. The effects of different factors on the inactivation of Escherichia coli were also evaluated, in term of the efficiency in inactivation. The results showed that Fe2O3-AgBr was able to inactivate both Gram negative (E. coli) and Gram positive (Staphylococcus aureus) bacteria. Bacterial inactivation by Fe2O3-AgBr was more favorable under high temperature and alkaline pH. Presence of Ca(2+) promoted the bacterial inactivation while the presence of [Formula: see text] was inhibitory. The mechanisms of photocatalytic bacterial inactivation were systemically studied and the effects of the presence of various specific reactive species scavengers and argon suggest that Fe2O3-AgBr inactivate bacterial cells by the oxidation of H2O2 generated from the photo-generated electron and direct oxidation of photo-generated hole. The detection of different reactive species further supported the proposed mechanisms. The results provide information for the evaluation of bacterial inactivation performance of Fe2O3-AgBr under different conditions. More importantly, bacterial inactivation for five consecutive cycles demonstrated Fe2O3-AgBr exhibited highly stable bactericidal activity and suggest that the magnetic Fe2O3-AgBr has great potential for water disinfection.
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
authors.forename: Tsz Wai
authors.initials: TW
authors.lastname: Ng
authors.affiliation: College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China. Electronic address: lszhang@dhu.edu.cn.
authors.forename: Lisha
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
authors.forename: Jianshe
authors.initials: J
authors.lastname: Liu
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Huang
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China; School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China. Electronic address: pkwong@cuhk.edu.hk.
authors.forename: Po Keung
authors.initials: PK
authors.lastname: Wong
mesh_terms: D001965:Bromides / Q000737:chemistry*; D002384:Catalysis; D004203:Disinfection / Q000379:methods*; D004926:Escherichia coli / Q000254:growth & development / Q000528:radiation effects*; D005290:Ferric Compounds / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D008027:Light; D060328:Magnetic Phenomena; D055668:Photochemical Processes; D018030:Silver Compounds / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000254:growth & development / Q000528:radiation effects; D018508:Water Purification / Q000379:methods
chemical_list: D001965:Bromides; D005290:Ferric Compounds; D018030:Silver Compounds; C000499:ferric oxide; D006861:Hydrogen Peroxide; C047751:silver bromide
keywords: Bacterial inactivation; Inactivation mechanisms; Magnetic photocatalyst