Photocatalytic Rejuvenation Enabled Self-Sanitizing, Reusable, and Biodegradable Masks Against COVID-19

Personal protective equipment (PPE) has been highly recommended by the U.S. Centers for Disease Control and Prevention (CDC) for self-protection under the disastrous SARS-CoV-2 (COVID-19) pandemic. Nevertheless, the massive utilization of PPE, especially the N95 respirators and sing-use masks, encounters significant challenges in recycling and sterilizing the used masks. To tackle the environmental pollution of currently used masks made of synthetic plastic, in this work, we designed a reusable, biodegradable, and antibacterial mask. The mask was prepared by electrospinning of polyvinyl alcohol (PVA), poly(ethylene oxide) (PEO), and cellulose nanofiber (CNF), and with subsequent esterification and then deposition of nitrogen-doped TiO₂ (N-TiO₂). The fabricated mask containing photocatalytic N-TiO₂ can reach ~100% sterilization under light source (200-2500 nm, 106 Wm^-2) as 0.1 sun simulation for only 10 min. Thus, the used mask can be rejuvenated through light irradiation and reused, which represents one of the handiest technologies for handling used masks. Furthermore, the intermolecular interactions between PVA, PEO and CNF enhanced electrospinnability and the mechanical performance of the resultant mask. The obtained masks possess superior mechanical strength (10-fold elastic modulus and 2-fold tensile strength higher than a commercial single use mask). The comprised electrospun nanofibers with porous structures in between as well as strong electrostatic attraction enabled breathability (83.4 L min^-1 of air flow rate) and superior particle filterability (98.7 %). Therefore, this novel mask could be a great alternative to current masks to addressing the urgent need for sustainable, reusable, environmentally friendly, and efficient personal protection designs under the ongoing COVID-19 contagion.