Tackling a new litter problem: Single-use face masks

The impacts of the coronavirus pandemic reach into almost every conceivable aspect of life. That includes litter being found around the globe.

Mask mandates have meant that the consumption of disposable face coverings has soared, and with it, the pollution caused by those same coverings being discarded improperly in the environment after use.

Apart from the challenge of dealing with such huge volumes of essential personal health care items in a sustainable way, simply throwing the used masks away for landfill disposal or incineration represents a loss of valuable feedstock for new material.

Fraunhofer Institute Umsicht, Sabic Innovative Polymers and consumer products giant Procter & Gamble Co. are collaborating on a project that will pilot a closed-loop recycling solution for single-use masks.

“Recognizing the challenge, we set out to explore how used face masks could potentially be returned into the value chain of new face mask production,” Peter Dziezok, director of R&D open innovation at Cincinnati-based P&G, said. “But creating a true circular solution from both a sustainable and an economically feasible perspective takes partners.”

The three partners came together from across the value chain. Each has a specific role to play. The pilot used disposable face masks collected by P&G that were worn by employees or given to visitors at the company’s manufacturing and research sites in Germany. Special collection bins were set up to dispose of the masks, which were then  sent to Fraunhofer for further processing in a dedicated research pyrolysis plant.

Mechanical recycling would have not done the job, said Alexander Hofmann, head of the department of recycling management at Fraunhofer Umsicht and head of research  for advanced recycling at Fraunhofer CCPE.

“In our solution, therefore, the masks were first automatically shredded and then thermochemically converted to pyrolysis oil. Pyrolysis breaks the plastic down into molecular fragments under pressure and heat, which will also destroy any residual pollutants or pathogens, such as the coronavirus. In this way it is possible to produce feedstock for new plastics in virgin quality that can also meet the requirements for medical products," Hofmann explained.

The pyrolysis oil was delivered to Sabic to be used as feedstock for the production of new polypropylene resin, in accordance with the mass balance approach.

“The circular material is part of our Trucircle portfolio, aimed at preventing valuable used plastic from becoming waste and at mitigating the depletion of fossil resources,” Mark Vester, global circular economy leader at Sabic, said.

Finally, to close the loop, the PP polymer was supplied to P&G, where it was processed into non-woven fiber material.

“This pilot project has helped us to assess if the close loop approach could work for hygienic and medical-grade plastics," said Hansjörg Reick, P&G senior director of open innovation. He conceded that further work was obviously needed, but noted that, "the results so far have been very encouraging."

The entire project from face mask collection to production, took seven months to develop and implement. The transferability of advanced recycling to other feedstocks and chemical products is being further researched at Fraunhofer CCPE.