title: Bacterial disinfection in a sunlight/visible-light-driven photocatalytic reactor by recyclable natural magnetic sphalerite.
abstract: A 5-L reactor was designed and used to enhance the sunlight/visible-light-driven (VLD) photocatalytic disinfection efficiency towards Gram-negative bacterium (Escherichia coli). Natural magnetic sphalerite (NMS) was used as the photocatalyst, which could be easily recycled by applying a magnetic field. Results showed that NMS with irradiation by the blue light emitting diode (LED) lamp could completely inactivate 1.5 × 105cfu/mL of E. coli within 120 min in the first three runs. However, the inactivation efficiency of E. coli started to decrease in the 4th Run, while in the 5th run, the E. coli with the initial concentration of 5 logs was inactivated to 3.3 (blue-light) and 3.5 logs (sunlight), respectively. Moreover, the stability and deactivation mechanism of NMS during subsequent runs were also studied. The results showed that the decline of the photocatalytic activity was possibly attributed to adsorption of the bacterial decomposed compounds on the active sites. In addition, photocatalytic bactericidal mechanism of the NMS in the photocatalytic system was investigated by using multiple scavengers to remove the specific reactive species. Moreover, various Gram-positive bacteria including Staphylococcus aureus, Microbacterium barkeri, and Bacillus subtilis could also be efficiently inactivated in the photocatalytic system.
authors.affiliation: School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR.
authors.forename: Xingxing
authors.initials: X
authors.lastname: Peng
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR.
authors.forename: Tsz Wai
authors.initials: TW
authors.lastname: Ng
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Huang
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR.
authors.forename: Wanjun
authors.initials: W
authors.lastname: Wang
authors.affiliation: Institute of Environmental Health and Pollution Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China. Electronic address: antc99@gdut.edu.cn.
authors.forename: Taicheng
authors.initials: T
authors.lastname: An
authors.affiliation: School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR. Electronic address: pkwong@cuhk.edu.hk.
authors.forename: Po Keung
authors.initials: PK
authors.lastname: Wong
mesh_terms: D002384:Catalysis; D004203:Disinfection / Q000379:methods*; D004926:Escherichia coli / Q000528:radiation effects*; D055668:Photochemical Processes; D013211:Staphylococcus aureus / Q000528:radiation effects*; D013440:Sulfides / Q000737:chemistry*; D013472:Sunlight; D014025:Titanium / Q000737:chemistry; D014871:Water Microbiology; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D013440:Sulfides; D017967:Zinc Compounds; D014025:Titanium; C031238:zinc sulfide
keywords: Bacterial disinfection; Disinfection reactor; Natural magnetic sphalerite; Sunlight/visible-light