A Portable Photocatalytic Oxidation System for Reuse of N95 Filtering Face-Mask Respirators

Covid-19 pandemic is becoming increasingly hazardous to humans, necessitating the use of additional Personal Protective Equipment (PPE) such as N95 Filtering Face-Mask Respirators (FFRs) and face shields to ensure the safety of our frontline personnel. The production of these is becoming an enormous burden, and researchers are attempting to alleviate this stress by designing systems that can make FFRs reuse [1] . Here we present a photocatalytic oxidation sterilization system based on UV-light and synergistically used metal oxide nanoparticles catalyst panels. It is a portable system for fast sterilization of FFRs to suit the growing and urgent requirements. Two indigenous ultraviolet (UV) light sterilization assemblies, having lantern UV-lamps arrangement and peaking at wavelength 254 nm, are fitted within a conventional Class II A2 biosafety cabinet in the developed system to deactivate bacteria and viruses from FFRs, in a portable protective environment. Metal oxide nanoparticle catalysts coated plates are utilized in conjunction with UV lamps in the advanced photocatalytic process. The system is optimized to deliver a UV dose of 1000 mJ/cm 2 for assured decontamination of FFRs in around 5 minutes of treatment time (CDC guidelines for UV dosage for FFR decontamination [2] ). The optimized system is exposed to 10 5 spores (Geobacillus Stearothermophilus) to verify sterilizing efficiency, and we achieved a 5 LOG reduction within 5 minutes of UV-exposure. In addition to bacteria and viruses, it can also remove odors, volatile organic compounds (VOCs), and any other suspended particles from FFRs. One can prepare more than 150 masks for reuse every day using the developed portable system.