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Discarded “single use” face masks pose a massive environmental challenge.
Several studies have demonstrated the feasibility of recycling these plastic-rich products into a range of materials, including LEDs and cement additives.
But the extent to which private industries will incorporate sustainable changes remains to be seen.
One of the many fallouts from the COVID-19 pandemic was the sheer volume of plastic medical waste used by both health care professionals and everyday individuals.
In 2021, researchers found that of the 8 million tons of plastic waste created during the pandemic, most ended up in the ocean, with the United States and China being the main perpetrators.
While some conscientious consumers hoped to avoid creating excess waste by donning cloth masks, the Centers for Disease Control and Prevention has since proclaimed these are less effective at stopping the spread of COVID-19 compared with disposable options like N95 or KN95 respirators.
But these alternatives are expensive and can only be used a limited number of times. Cheaper, albeit just as short-lived options, like disposable polypropylene-based masks have thus become ubiquitous.
On an individual level, several companies have taken the initiative to collect and recycle masks discarded in-home. Since masks cannot be recycled with traditional streams of plastic and metal, one organization based out of Trenton, N.J., TerraCycle, sells Zero Waste Boxes to customers who can then send back a full box of used personal protective equipment (PPE).
But legal restrictions preclude the company from collecting PPE from medical facilities, hospitals or doctor’s offices. After 72 hours, TerraCycle sorts the waste based on material and sends it to a third party where nonwoven plastics become plastic pellets and metals are made into bar stock or metal sheeting.
“The polypropylene-dominant mixture from the face mask is densified into a crumb-like raw material that’s used in plastic lumber and composite decking applications,” TerraCycle’s website reads, while “the elastane or rubber band portion is ground into a fine mesh regrind and mixed with recycled plastics as an additive to provide flexibility and malleability to products.”
Additional organizations operate similar systems around the world.
Not only are masks hazardous to animal life, but their plastic makeup means they cannot easily break down in the natural environment and, if littered, eventually become microplastics and pose an additional set of problems.
When disposed of in the garbage, the masks can take up limited landfill space and contribute to greenhouse gas emissions or be incinerated, compounding the release of emissions and negatively impacting human health.
In addition to personal recycling of discarded PPE, large-scale solutions can tackle the hefty ramifications of irresponsible disposal and the high volume of waste created by the health care industry.
In the 2021 report, authors found waste generated by hospitals “dwarfs the contribution from personal protection equipment,” while the industry as a whole has come under fire as it accounts for around 8.5 percent of the country’s total carbon emissions.
In light of these figures, scientists have stepped up to design sustainable ways of upcycling used PPE, particularly masks.
Researchers in Australia met the challenge by assessing the feasibility of transforming masks into roadways, and found the product could be used to create two of the four layers typically used in the construction process.
An additional study published in April 2022 took PPE waste, including masks, and showed the materials could be used to create white LEDs.
Scientists have also assessed the effects of treated face mask chips in granular soil, used most commonly in backfill, railways and construction, and found it to be a suitable ingredient.
Xianming Shi, a professor of civil and environmental engineering at Washington State University, co-authored one of these papers.
“Oftentimes, waste is just misplaced resources,” Shi said in an interview with Changing America, adding that upcycling these materials can help unlock their potential.
In lab experiments, Shi and colleagues pretreated microfibers from face masks in a novel nano-material graphene oxide solution. Treated mask fibers were then added to cement paste constituting a 0.1 vol% for a water/cement ratio of 0.4.
After testing the final product for durability and strength, Shi says the mixture actually benefited the concrete.
The concrete’s resistance to damage was improved by 20 percent after the graphene oxide material was incorporated. In a typical coastal environment like Seattle, ordinary cement used in a pier would last for approximately 30 or 40 years, Shi said.
“But if we add this graphene oxide treated microfiber, based on the lab testing results, you’re bumping that up to 55 years, so that’s a 63 percent increase in service life,” he said. This is due in large part to the synergistic effect between the treatment and mask microfibers.
If this process were to be implemented on a larger scale, masks would first need to be sterilized to kill any microbes or viruses, authors wrote. But one benefit to this solution is that any heavy metals or contaminants present in the masks would be concrete bound or “chemically locked up,” Shi said.
“Concrete is a really good host material. Anything you put in … won’t leach out at any significant rate.”
Concrete also happens to be the second most used material in the world among humans behind water. Each person uses about 3 tons of concrete annually, thanks to roads, buildings, bridges and other infrastructure.
Even though the process is technically feasible, “how to incentivize the private sector to invest in such technologies is beyond our control,” Shi explained.
The passage of President Biden’s Infrastructure Investment and Jobs Act (IIJA), which provides $550 billion in new infrastructure funding, might provide some opportunities. The law specifically calls for increased action ensuring “energy efficiency of the production of paving materials and the ability of paving materials to enhance the environment and promote sustainability.”
Cement is an ingredient of concrete, widely used for road construction and paving. A report from the American Concrete Pavement Association (ACPA) on the Infrastructure Investment and Jobs Act notes “the legislation authorizes $304 billion to the Highway Trust Fund for roads and bridges over five years with approximately $100 billion in new spending for roadways specifically.”
Changing America has reached out to the ACPA to ask if it plans to incorporate any sustainable solutions at a national level in the wake of the legislation’s passage.
For Shi, he hopes the law will spur agencies into action.
“Without sufficient funding, usually there’s plenty of deferred maintenance. There’s no room for innovation,” he said. “But with the increased investment, I think it’s definitely going to inspire both the public sector and the private sector to look for more long term solutions and more sustainable solutions.”
Shi also noted that even though the process used in his team’s lab experiments was innovative, he doesn’t plan to file a patent for it.
“The whole purpose is to demonstrate the beneficial use of masks and inspire people to collect the masks knowing that it could be turned into a valuable resource,” he said.
Even without using the new nano-material, significant improvements in cement tensile strength can be achieved just by grinding down masks into microfiber, he said.