Water-Repellent TiO2-Organic Dye-Based Air Filters for Efficient Visible-Light-Activated Photochemical Inactivation against Bioaerosols

Recently, bioaerosols, including the 2019 novel coronavirus, pose a serious threat to global public health. Herein, we introduce a visible-light-activated (VLA) antimicrobial air filter functionalized with titanium dioxide (TiO2)-crystal violet (CV) nanocomposites facilitating abandoned visible light from sunlight or indoor lights. The TiO2-CV based VLA antimicrobial air filters exhibit a potent inactivation rate of similar to 99.98% and filtration efficiency of similar to 99.9% against various bioaerosols. Under visible-light, the CV is involved in overall inactivation by inducing reactive oxygen species production both directly (CV itself) and indirectly (in combination with TiO2). Moreover, the susceptibility of the CV to humidity was significantly improved by forming a hydrophobic molecular layer on the TiO2 surface, highlighting its potential applicability in real environments such as exhaled or humid air. We believe this work can open a new avenue for designing and realizing practical antimicrobial technology using ubiquitous visible- light energy against the threat of infectious bioaerosols.

Automated summary

Bioaerosols, including the 2019 novel coronavirus, are a serious global public health threat. A visible-light-activated antimicrobial air filter with titanium dioxide-crystal violet nanocomposites demonstrates high antimicrobial inactivation and filtration efficiency. Crystal violet plays a role in inducing reactive oxygen species production both directly and indirectly. Improved humidity resistance highlights its potential applicability in real environments.