Dry aerosol coating of anti-viral particles on commercial air filters using a high-volume flow atomizer

Filtration is a common air cleaning technique used to remove airborne particulates. However, microorganisms can survive and multiply on the filter’s surface in heating, ventilation, and air-conditioning systems. These multiplied microorganisms eventually disperse in the air. The most conventional method of coating pristine air filter media with anti-viral material involves applying a wet coating via solution processing, wherein the filter media needs to be soaked in a solution containing a large amount of dispersed anti-viral material, and then drying the coated filter using a heated air flow. However, the latter step requires additional time and energy and often causes the deformation of the filter material. By contrast, applying an aerosolized coating is a dry process, wherein aerosolized anti-viral material is directly deposited on the filter at atmospheric pressure and room temperature. In this work, we design a laboratory-made atomizer to generate highly concentrated aerosolized particles at a high flow rate (> 200 L min^–1). The generated anti-viral material (SiO₂-Ag nanoparticles), which includes liquid droplets, is dried by a sheath air flow and directly applied to a commercial air filter unit. The coated anti-viral filter is evaluated for filtration efficiency and anti-viral activity against aerosolized MS2 bacteriophage.