title: An Environmentally Friendly Method for Testing Photocatalytic Inactivation of Cyanobacterial Propagation on a Hybrid Ag-TiO₂ Photocatalyst under Solar Illumination.
abstract: Cyanobacteria were inactivated under sunlight using mixed phase silver (Ag) and deposited titanium dioxide (TiO₂) coated on the surface of diatomite (DM) as a hybrid photocatalyst (Ag-TiO₂/DM). The endpoints of dose-response experiments were chlorophyll a, photosynthetic efficiency, and flow cytometry measurements. In vitro experiments revealed that axenic cultures of planktonic cyanobacteria lost their photosynthetic activity following photocatalyzed exposure to sunlight for more than 24 h. Nearly 92% of Microcystis aeruginosa cells lost their photosynthetic activity, and their cell morphology was severely damaged within 24 h of the reaction. Preliminary carbon-14 ((14)CO₃(-2)) results suggest that the complete inactivation of cyanobacteria arises from damage to cell wall components (peroxidation). A small concomitant increase in cell wall disorder and a consequent decrease in cell wall functional groups increase the cell wall fluidity prior to cell lysis. A high dosage of Ag-TiO₂/DM during photocatalysis increased the concentration of extracellular polymeric substances (EPSs) in the Microcystis aeruginosa suspension by up to approximately 260%. However, photocatalytic treatment had a small effect on the disinfection by-product (DBP) precursor, as revealed by only a slight increase in the formation of trihalomethanes (THMs) and haloacetic acids (HAAs).
authors.affiliation: Kuang-Tien General Hospital, No. 117, Satien Road, Shalu District, Taichung 43303, Taiwan. hollyspirit31@yahoo.com.tw.
authors.forename: Shu-Yu
authors.initials: SY
authors.lastname: Chang
authors.affiliation: Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 1018 Sec. 6, Taiwan Boulevard, Shalu District, Taichung 43302, Taiwan. huangwj@sunrise.hk.edu.tw.
authors.forename: Winn-Jung
authors.initials: WJ
authors.lastname: Huang
authors.affiliation: Department of Electronics and Communication Engineering, Peking University, No. 5, Zhuangyuan Road, Binhu District, Wuxi 214125, China. a22462863@yahoo.com.tw.
authors.forename: Ben-Ren
authors.initials: BR
authors.lastname: Lu
authors.affiliation: Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 1018 Sec. 6, Taiwan Boulevard, Shalu District, Taichung 43302, Taiwan. gcfang@sunrise.hk.edu.tw.
authors.forename: Guor-Cheng
authors.initials: GC
authors.lastname: Fang
authors.affiliation: Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 1018 Sec. 6, Taiwan Boulevard, Shalu District, Taichung 43302, Taiwan. bluecrystalprotein@gmail.com.
authors.forename: Yeah
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 1018 Sec. 6, Taiwan Boulevard, Shalu District, Taichung 43302, Taiwan. hsiulin@sunrise.hk.edu.tw.
authors.forename: Hsiu-Lin
authors.initials: HL
authors.lastname: Chen
authors.affiliation: Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 1018 Sec. 6, Taiwan Boulevard, Shalu District, Taichung 43302, Taiwan. chang@sunrise.hk.edu.tw.
authors.forename: Ming-Chin
authors.initials: MC
authors.lastname: Chang
authors.affiliation: Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 1018 Sec. 6, Taiwan Boulevard, Shalu District, Taichung 43302, Taiwan. yetihsu@yahoo.com.tw.
authors.forename: Cheng-Feng
authors.initials: CF
authors.lastname: Hsu
mesh_terms: D049109:Cell Proliferation; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D000458:Cyanobacteria / Q000502:physiology*; D007692:Diatomaceous Earth; D004203:Disinfection / Q000379:methods*; D046931:Microcystis / Q000502:physiology; D010788:Photosynthesis / Q000502:physiology; D012834:Silver; D013472:Sunlight; D014025:Titanium
chemical_list: D002734:Chlorophyll; C009495:titanium dioxide; D012834:Silver; D007692:Diatomaceous Earth; C033787:diatomite; D014025:Titanium; D000077194:Chlorophyll A
keywords: cyanobacteria; disinfection by-products; extracellular polymeric substances; photocatalysis; silver; titanium dioxide