University of Delaware researchers have developed an innovative method to mitigate environmental contamination from discarded tires, opening a path to safer recycling practices that turn harmful components into valuable products.
Researchers at the University of Delaware have unveiled a groundbreaking method to tackle one of the often-overlooked sources of pollution: old tires. The new study, published in Nature Chemical Engineering, introduces a process that chemically converts harmful tire components into safe, reusable materials.
The research team, led by Dion Vlachos, chair of UD’s Department of Chemical and Biomolecular Engineering, has devised a technique to upgrade 6PPD, a molecule in tires that offers UV protection but converts into a dangerous pollutant, 6PPD-quinone.
This innovation could reshape the way we handle tire disposal by turning leftover tire materials into useful products such as aromatics and carbon black, which are found in everyday items ranging from cosmetics to electronics.
“Tires are responsible for about one-third of the microplastics in the environment,” according to Vlachos, who also heads the Delaware Energy Institute.
Under the exposure to sunlight, 6PPD transforms into 6PPD-quinone, releasing harmful diketone molecules into the atmosphere from tires not only in use but also those abandoned in landfills.
Traditional efforts to break down tire materials, like those involving high-heat pyrolysis, have struggled to address the stubborn 6PPD chemicals.
Thus, the University of Delaware team took a different approach, using chemical extraction. By heating tire crumbs in a microwave reactor and separating the molecules using a solvent, they effectively removed 6PPD. The extracted molecules then underwent a chemical conversion to become safe, marketable chemicals.
The remaining tire material was found suitable for recycling through conventional methods, making it feasible to reuse in applications such as playground surfaces, roads and other commercial products.
This could solve a significant part of the pressing global issue of tire waste. Experts estimate that there could be up to 5 billion tires requiring disposal worldwide by 2030, and the United States saw a 25% decline in scrap tire use between 2013 and 2021.
“I think actual recycling of the tire itself is important, so there are truly circular solutions that are doing upcycling,” Vlachos said in a news release. “We must make things at a large enough scale and at a reasonable cost outside of the laboratory. This has to be demonstrated with pilot-scale facilities. We haven’t done that.”
The study points to the potential for real-world impact but acknowledges the necessity of further engineering efforts and industry collaboration for mass adoption.
“We need to educate the community. We need social sensitivity, awareness. It’s not a problem that will solve itself,” added Vlachos.
As environmental concerns grow, this study offers a hopeful path forward, promising safer, more sustainable recycling practices that benefit both industry and planet.