Researchers at the University of Waterloo have developed a solar-powered method to convert plastic waste into acetic acid, the main component of vinegar.
The process uses sunlight and a specially engineered catalyst to break down plastics at the molecular level, offering a potential new route for upcycling waste without adding carbon dioxide to the atmosphere.
The team designed a bio-inspired cascade photocatalysis system built around iron single atoms embedded in carbon nitride.
When exposed to sunlight, the material triggers a sequence of chemical reactions that transform common plastic polymers into acetic acid with high selectivity.
Unlike many recycling methods that rely on heat or fossil-fuel-derived energy, this approach runs on solar power and operates in water.
That makes it particularly relevant for addressing microplastics in aquatic environments.
The system was tested on widely used plastics including PVC, PP, PE and PET.
It also remained effective when processing mixed plastic streams, a key requirement for real-world waste treatment.
Solar-driven plastic upcycling
Plastic waste, especially microplastics, has been detected across marine and terrestrial ecosystems.
The accumulation of these materials has raised concerns about impacts on wildlife and human health.
“Our goal was to solve the plastic pollution challenge by converting microplastic waste into high-value products using sunlight,” said Dr. Yimin Wu, a professor of mechanical and mechatronics engineering and the Tang Family Chair in New Energy Materials and Sustainability.
The research was led by Waterloo PhD student Wei Wei under Wu’s guidance.
Early-stage support came from a joint seed fund from the Waterloo Institute for Nanotechnology and the Water Institute.
The catalyst design takes inspiration from natural systems. Certain fungi use enzymes to break down complex organic matter through stepwise reactions.
Similarly, the Waterloo team engineered a cascade reaction pathway that incrementally degrades plastic polymers into acetic acid.
Single-atom catalyst design
At the core of the system are isolated iron atoms dispersed within a carbon nitride framework.
These single-atom sites improve reaction control and efficiency under sunlight, enabling the selective production of acetic acid rather than a mixture of byproducts.
Acetic acid has broad industrial applications, from food production to chemical manufacturing and energy systems. Converting plastic waste into this compound creates a value-added product while reducing pollution.
The researchers also conducted a techno-economic analysis to assess commercial viability.
“Both from a business and societal perspective, the financial and economic benefits associated with this innovation seem promising,” said Roy Brouwer, executive director of the Water Institute and a coauthor of the article supporting the techno-economic analysis.
Wu emphasized the environmental advantage of the approach. “This method allows abundant and free solar energy to break down plastic pollution without adding extra carbon dioxide to the atmosphere,” he said.
Because the reaction occurs in water and breaks plastics down at the chemical level, it may offer a way to address microplastics directly rather than simply filtering them out.
While the system remains at the laboratory stage, the team says it could be further optimized and scaled through materials engineering and manufacturing advances.