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 ( 1 O 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 1 O 2 sensitizer, can be used for heterogeneous gas-phase generation of 1 O 2 . It was confirmed that irradiation of the RB filter under oxygen gas stream produced 1 O 2 , which was measured using furfuryl alcohol trapping method followed by HPLC analysis. It was also observed that the amount of 1 O 2 generated increases as the light intensity increased. Similarly, the sensitizer loading also positively influenced the 1 O 2 generation. The heterogeneous gas-phase generation of 1 O 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. Graphical abstract Unlabelled Image Highlights • Gas-phase singlet oxygen ( 1 O 2 ) generation from Rose Bengal-impregnated filter • A simple experimental set-up for gas phase 1 O 2 estimation from impregnated filter • Sensitizer loading and light intensity were the most important factors. • Potential application of 1 O 2 for indoor bacteria/virus inactivation in air