An Environmentally Friendly Method for Testing Photocatalytic Inactivation of Cyanobacterial Propagation on a Hybrid Ag-TiO2 Photocatalyst under Solar Illumination

International Journal of Environmental Research and Public Health

Shu-Yu Chang²  Winn-Jung Huang¹  Ben-Ren Lu³  Guor-Cheng Fang¹  Yeah Chen¹  Hsiu-Lin Chen¹  Ming-Chin Chang¹  Cheng-Feng Hsu¹  Nicholas Frederick Gray⁴ 

[1] Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 1018 Sec. 6, Taiwan Boulevard, Shalu District, Taichung 43302, Taiwan;Kuang-Tien General Hospital, No. 117, Satien Road, Shalu District, Taichung 43303, Taiwan;Department of Electronics and Communication Engineering, Peking University, No. 5, Zhuangyuan Road, Binhu District, Wuxi 214125, China;;Kuang-Tien General Hospital, No. 117, Satien Road, Shalu District, Taichung 43303, Taiwan

关键词: photocatalysis;    silver;    titanium dioxide;    cyanobacteria;    extracellular polymeric substances;    disinfection by-products;   

DOI  :  10.3390/ijerph121215023

来源: mdpi

【 摘 要 】

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 (¹⁴CO₃⁻²) 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).

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.