The photocatalytic disinfection of aerosolized Escherichia coli, a pathogenic microorganism was investigated. The air disinfection system is a novel TiO2 thin films/glass reactor filter and ultraviolet (UV) radiation air purification system, operating at a flow rate of 20 L/min. A special glass fiber reactor design allowed the UV lamp to be located in the center of the reactor. The photocatalyst reactor was then filled with TiO2 coated glass fiber substrates to examine the photocatalytic efficiency of the TiO2 filled reactor against aerosolized E. coli in cell concentrations of 105 CFU/mL. A slow sol–gel technique hydrolysis was used in this study to acquire fine and uniform TiO2 nanoparticles of 10–30 nm. The TiO2 thin films were obtained on glass fiber substrates by dipping method followed by thermal treatment. In an attempt to understand the structure and the morphology of TiO2 sol–gel thin films, analyses by X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed. The SEM images showed that uniform anatase TiO2 thin films were coated on fiber surfaces. A neublizer was applied to yield E. coli bioaerosol at a controlled humidity of 72%. Disinfection of E. coli under 254 and 365 nm light illumination was conducted to evaluate the photocatalytic ability of the TiO2 thin films. The nano-TiO2/glass fibers gel catalyst prepared in the laboratory showed good photocatalytic performance with the high degradation efficiency above 95% at both wavelengths. With the UV illumination switched off, the degradation efficiency dropped to below 60%. The improvement of the photocatalytic activity was ascribed to the fibers-based reactor with a screen mechanism which provided a huge surface area of TiO2 thin films. These results will be useful and assist engineers to design photocatalyst reactors for the industrial applications of bioaerosol removal.
關聯:
Surface and Coatings Technology Volume 205, Supplement 1 Pages S341–S344
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