Scientists at Northwestern University have discovered a simple, eco-friendly way to break down plastic using just air moisture and a low-cost catalyst.
This new method could revolutionize plastic recycling, making it safer, cheaper, and more sustainable.
Plastic pollution is a major problem worldwide, and the U.S. is one of the biggest contributors. Currently, only about 5% of plastic is recycled.
Most recycling methods involve melting plastic and turning it into lower-quality products. However, these processes require a lot of energy, use harmful chemicals, and produce toxic waste.
Researchers at Northwestern University have found a better way.
Their new method breaks down polyethylene terephthalate (PET)—a common plastic found in bottles and packaging—without the need for harmful solvents or high temperatures.
Instead, they use a simple catalyst and moisture from the air to break the plastic down into its basic building blocks, called monomers. These monomers can then be used to make new plastic or even more valuable materials.
The process starts with a special catalyst made of molybdenum and activated carbon—both inexpensive and non-toxic materials.
When PET plastic is heated with this catalyst, its chemical bonds start to break apart.
Then, when the broken-down plastic is exposed to air, tiny amounts of moisture help complete the reaction, turning it into terephthalic acid (TPA).
TPA is an important ingredient for making new plastic and other useful materials. The only byproduct is acetaldehyde, a harmless and easy-to-remove chemical used in industry.
“The moisture in the air was just the right amount for the process to work perfectly,” said lead researcher Yosi Kratish. “When we added extra water, it stopped working, showing that nature already provides the ideal conditions.”
Traditional recycling methods often require sorting different types of plastic, which can be expensive and time-consuming.
The new method, however, works selectively on polyester plastics, meaning it can break down PET without requiring pre-sorting. This makes it much more practical for large-scale recycling.
In tests, the process successfully broke down 94% of plastic waste in just four hours. It also worked on real-world plastic items like bottles, clothing, and mixed plastic waste. Even colored plastics were broken down into pure, colorless TPA.
The research team hopes to scale up this technology for industrial use. If successful, it could significantly reduce plastic waste and support a circular economy where plastic is continuously reused instead of thrown away.
“This discovery offers a clean and efficient way to recycle plastic,” said researcher Naveen Malik.
“It shows how science can help solve one of the world’s biggest environmental challenges while working in harmony with nature.”
