title: Efficient Photocatalytic Disinfection of Escherichia coli O157:H7 using C70-TiO2 Hybrid under Visible Light Irradiation.
abstract: Efficient photocatalytic disinfection of Escherichia coli O157:H7 was achieved by using a C70 modified TiO2 (C70-TiO2) hybrid as a photocatalyst under visible light (λ > 420 nm) irradiation. Disinfection experiments showed that 73% of E. coli O157:H7 died within 2 h with a disinfection rate constant of k = 0.01 min(-1), which is three times that measured for TiO2. The mechanism of cell death was investigated by using several scavengers combined with a partition system. The results revealed that diffusing hydroxyl radicals play an important role in the photocatalytically initiated bacterial death, and direct contact between C70-TiO2 hybrid and bacteria is not indispensable in the photocatalytic disinfection process. Extracellular polymeric substances (EPS) of bacteria have little effect on the disinfection efficiency. Analyses of the inhibitory effect of C70-TiO2 thin films on E. coli O157:H7 showed a decrease of the bacterial concentration from 3 × 10(8) to 38 cfu mL(-1) in the solution with C70-TiO2 thin film in the first 2 h of irradiation and a complete inhibition of the growth of E. coli O157:H7 in the later 24 h irradiation.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Ouyang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Dai
authors.affiliation: Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, USA.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Walker
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Qiaoyun
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Jinan Research Academy of Environmental Sciences, Jinan 250014, China.
authors.forename: Xixiang
authors.initials: X
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Cai
mesh_terms: D002384:Catalysis / Q000187:drug effects / Q000528:radiation effects; D004203:Disinfection / Q000379:methods*; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development / Q000528:radiation effects*; D037741:Fullerenes / Q000737:chemistry / Q000494:pharmacology*; D008027:Light; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects; D008854:Microscopy, Electron; D013997:Time Factors; D014025:Titanium / Q000737:chemistry / Q000494:pharmacology*; D014961:X-Ray Diffraction
chemical_list: D037741:Fullerenes; C069836:fullerene C70; C009495:titanium dioxide; D014025:Titanium