Perhaps one of the most striking lifestyle changes resulting from the COVID-19 pandemic is the mandatory use of face masks in grocery stores, restaurants, and other public places. Wearing a mask, especially when near others, is imperative to slowing the spread of COVID-19. With such a drastic increase in masks’ usage, an enormous amount of plastic pollution is being created, which is already one of the most significant environmental issues facing our society.
Biodegradable masks could be one of the options to reduce such pollution. Sung Yeon Hwang, professor at the Korea Research Institute of Chemical Technology (KRICT), said, “We believe biodegradable masks are the answer to this problem. Contaminated plastic masks are difficult to recycle and must be incinerated or sent to a landfill.” The researchers reported a biodegradable and moisture‐resistant mask filter made from polybutylene succinate (PBS). PBS is a biodegradable plastic resin and it was coated with chitosan nanowhiskers. The filter material is what the team classifies as a “nonwoven” fabric, a sheet or web of structures bonded together by entangling fibers or filaments.
The filter, which on its own would have inadequate performance against small particles, such as SARS-CoV-2 aerosols, is then enhanced with a coating of chitosan nanowhiskers. These nanowhiskers are the positively charged microfibers made from the shells of crustaceans. By soaking the filters in a solution of the nanowhiskers, the biodegradable filters become permanently coated. They have an increased ability to trap tiny particles due to the nanowhisker’s positive charge.
The team’s experiments showed that the biodegradable filter was just as efficient as N95 filters, removing 98.3% of 2.5 µm (PM2.5) particles in a test and decomposing within 4 weeks of composting soil. Such biodegradable masks with comparable performance to conventional non-biodegradable masks offer enormous benefits for the environment.
