Photocatalytic Inactivation of Legionella Pneumophila and an Aerobic Bacteria Consortium in Water over TiO2/SiO2 Fibres in a Continuous Reactor

摘要: A continuous photoreactor, working in a total recycle mode and irradiated by low-pressure Hg lamp, has been used to study the bactericidal effect of photocatalyst, formed TiO2 embedded SiO2 fibres, on Legionella pneumophila consortium common gram-negative aerobic bacteria (Escherichia coli, Klebsiella sp., Pseudomona sp. Proteus sp.) water. The kinetic modeling inactivation process, carried out with measured values viable concentration at outlet evidenced that for each pass inside photoreactor ratio between inlet cell concentrations was order 0.01 L. pneumophila. For other bacteria, which are usually taken as reference photocatalytic studies, this 0.3 first hour illumination, while upon prolonged irradiation (up 9 h) increased 0.7. Several factors inducing latter decrease efficiency possible, e.g. competition attack microorganisms organic compounds released damaged or photoinduced alteration small fraction still making them less interactive photocatalyst. mechanism normally proposed involves an initial photogenerated radicals outer membrane; consequent membrane dispersion allows damage cytoplasmic membrane. higher lethality method observed towards (in comparison bacteria) is explained considering secretion system, adapted high virulence would become activated through adhesion surface. This then be able inactivate without dispersing Apart from this, water flow catalyst fibres can facilitate transport anatase surface, additionally generated shear stress may help adhesion, least some E. contributing further improve photokilling efficiency; both contribute configuration.