Plasma Degradation of Contaminated PPE: A New Energy Efficient Method to Treat Contaminated Plastic Waste

Management of contaminated PPE from the healthcare sector has always been a challenge as it must be treated as biohazardous waste and as such must be incinerated. Recently, because of the SARS-CoV-2 (COVID-19) pandemic, the use of PPE has drastically increased. In particular, single use (disposable) surgical face masks have generated a significant amount of waste. Such masks are made from non-biodegradable polymers, and as such take a very long time to degrade in the environment when carelessly discarded. In this work, an alternative low-power plasma method has been used to successfully and efficiently degrade surgical masks. Several analytical techniques [gravimetric analysis, SEM, ATR-IR and XPS, TGA/DSC and wide-angle x-ray scattering (WAXS)] were used to evaluate the effects of plasma irradiation on the individual non-woven layers that make up polypropylene (PP) disposable face masks. After 4 hours of plasma irradiation, an overall mass loss of 63 ± 8% was observed on the non-woven 3-ply surgical mask. This mass loss rate is over 20 times faster than degrading a bulk PP sample. Individual components of the mask also showed different degradation rates; for example, 99% degradation was observed for the middle filter layer while only 9% was observed from the elasticated ear loop. ATR-IR and XPS confirmed the plasma-induced oxidation of the polypropylene structure of the mask layers, while results from TGA/DSC and WAXS suggested that the polymer has been fragmented after plasma irradiation. Air plasma clearly represents a new tool for treating contaminated PPE in an energy-efficient and environmentally friendly approach.