Bacteria and fungi inactivation by photocatalysis under UVA irradiation: liquid and gas phase

• Published in: Environmental science and pollution research international 2017-03, Vol.24 (7), p.6372-6381
• Main Authors: Rodrigues-Silva, Caio, Miranda, Sandra M., Lopes, Filipe V. S., Silva, Mário, Dezotti, Márcia, Silva, Adrián M. T., Faria, Joaquim L., Boaventura, Rui A. R., Vilar, Vítor J. P., Pinto, Eugénia
• Format: Article
• Language: English
• Subjects: Air Microbiology; Air sampling; AOPs: Recent Advances to Overcome Barriers in the Treatment of Water; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bacteria; Bacteria - isolation & purification; Catalysis; Cellulose - analogs & derivatives; Cellulose - chemistry; Cellulose acetate; E coli; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental risk; Environmental science; Fungi; Fungi - isolation & purification; Gases; Gram-negative bacteria; Gram-positive bacteria; Inactivation; Indoor environments; Irradiation; Laboratories; Legislation; Load distribution; Microbial Viability - radiation effects; Microorganisms; Oxidation; Performance evaluation; Photocatalysis; Photolysis; Slurries; Staphylococcus infections; Studies; Survival; Titanium; Titanium - chemistry; Titanium dioxide; Ultraviolet radiation; Ultraviolet Rays; VOCs; Volatile organic compounds; Waste Water - microbiology; Waste Water Technology; Wastewater and Air; Wastewater treatment plants; Water Management; Water Pollution Control; Water Purification; Water treatment; Water treatment plants; Zinc Oxide - chemistry; Zinc oxides
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-016-7137-8

In the last decade, environmental risks associated with wastewater treatment plants (WWTPs) have become a concern in the scientific community due to the absence of specific legislation governing the occupational exposure limits (OEL) for microorganisms present in indoor air. Thus, it is necessary to develop techniques to effectively inactivate microorganisms present in the air of WWTPs facilities. In the present work, ultraviolet light A radiation was used as inactivation tool. The microbial population was not visibly reduced in the bioaerosol by ultraviolet light A (UVA) photolysis. The UVA photocatalytic process for the inactivation of microorganisms (bacteria and fungi, ATCC strains and isolates from indoor air samples of a WWTP) using titanium dioxide (TiO 2 P25) and zinc oxide (ZnO) was tested in both liquid-phase and airborne conditions. In the slurry conditions at liquid phase, P25 showed a better performance in inactivation. For this reason, gas-phase assays were performed in a tubular photoreactor packed with cellulose acetate monolithic structures coated with P25. The survival rate of microorganisms under study decreased with the catalyst load and the UVA exposure time. Inactivation of fungi was slower than resistant bacteria, followed by Gram-positive bacteria and Gram-negative bacteria. Graphical abstract Inactivation of fungi and bacteria in gas phase by photocatalitic process performed in a tubular photoreactor packed with cellulose acetate monolith structures coated with TiO 2