Breathing green: Sustainable approaches for the reuse of FFP2 facemasks

Facemasks are essential components in healthcare environments, but their disposal represents a significant environmental concern. This study proposes an optimized sterilization treatment for the reprocessing of electrostatic filter (EF) and mechanical filter (MF) facemasks using supercritical carbon dioxide (scCO 2 ) and hydrogen peroxide, achieving a Sterility Assurance Level (SAL) of 10 -6 in microbial load. The performance of the facemasks was evaluated after 1, 5, and 10 cycles and compared with those subjected to ethylene oxide and to γ-rays sterilization procedure, in terms of filtration efficiency, breathability, electrostatic charges of the filters, and of mechanical properties of the elastic bands. Structural and chemical changes were characterized using SEM and FTIR. The findings demonstrated that scCO 2 treatment induced electrostatic charges in the MF, improving their filtration efficiency. The supercritical treatment also preserved the chemical and structural integrity of both types of filters. Results underscore the effectiveness of the scCO 2 method as a viable and sustainable alternative to conventional sterilization methods. An innovative sterilization protocol based on CO 2 was developed preserving FFP2 facemask’s structure and inducing new electrostatic charges after treatment. • A new sterilization process based on scCO 2 and H 2 O 2 was established. • Electrostatic and mechanical filters underwent different sterilization treatments. • Electrostatic facemask structure remained intact after 10 cycles of scCO 2 treatment. • Mechanical facemask acquired electrostatic charges after the scCO 2 treatment.