A simple, inexpensive method for gas-phase singlet oxygen generation from sensitizer-impregnated filters: Potential application to bacteria/virus inactivation and pollutant degradation

Airborne infectious diseases such as the new Coronavirus 2019 (COVID-19) pose serious threat to human health. Indoor air pollution is a problem of global environmental concern as well. Singlet oxygen (O-1(2)) is a reactive oxygen species that plays important role in bacteria/virus inactivation and pollutant degradation. In this study, we found that commercially available filters typically deployed in air purifier and air conditioning units, when impregnated with Rose Bengal (RB) as a O-1(2) sensitizer, can be used for heterogeneous gas-phase generation of O-1(2). It was confirmed that irradiation of the RB filter under oxygen gas stream produced O-1(2), which was measured using furfuryl alcohol trapping method followed by HPLC analysis. It was also observed that the amount of O-1(2) generated increases as the light intensity increased. Similarly, the sensitizer loading also positively influenced the O-1(2) generation. The heterogeneous gas-phase generation of O-1(2) can find potential applications in air purifier and air conditioning units for the purpose of bacteria/virus inactivation and/or pollutant degradation thereby improving indoor air quality. (C) 2020 Elsevier B.V. All rights reserved.