Inactivation of Bioaerosols using Vacuum UV Light

Abstract

Recently, due to pandemic viruses such as corona and influenza viruses, many people have become aware of the importance of indoor air disinfection. Therefore, many research has been actively conducted for inactivating bio-aerosols. Among them, ultraviolet (UV) photocatalysis is known as a high-level oxidation treatment technology because it is more efficient than conventional methods, such as filtration & heat treatment, and is easy to maintain and manage. However, using a general UV light with a long wavelength shows low photocatalytic efficiency in a short reaction time. Therefore, this study proposes a technology that can efficiently inactivate bio-aerosols in a very short reaction time. In this study, the inactivation of Pseudomonas fluorescens and MS2 bacteriophage was observed by irradiating 185 nm vacuum ultraviolet (VUV) light onto TiO2 photocatalyst. VUV has stronger photon energies than conventional UV light, so it can destroy most chemical contaminants and generate strong oxides, such as hydroxyl radicals, reactive oxygen species (ROS), and ozone. Ozone, generated by the reaction of VUV light and oxygen in the air, acted as an effective oxidizing agent, but excessive ozone can adversely affect the health. Therefore, in this study, we developed a 2 mm pleated catalyst to inactivate both bio-aerosols and produced ozone, and to enhance the photocatalytic activity, we attached palladium (Pd) with high ozone oxidation power to TiO2 catalyst. When VUV was applied to P. fluorescens and MS2 for 0.009 second, 100% and 90% inactivation efficiency were observed, respectively, and overall ozone degradation efficiency was 75% or more. The system is expected to replace existing UV-based air purifiers in that it can inactivate bio-aerosols in a very short time.