GabyResearchers at Northwestern University in the U.S. found a way to break down plastic waste using moisture from the air. The process turns a common type of plastic into a byproduct that can be recycled into higher-value materials.
By applying an inexpensive catalyst to a common type of plastic and leaving it outdoors, the team decomposed 94 percent of the material in just four hours.
The inventors say the process is safer, cheaper, and more environmentally friendly than many other plastic recycling methods.
What makes the method unique?
In search of new ways to break down plastic waste, the team mixed PET (polyethylene terephthalate—the most common polyester plastic) with a molybdenum catalyst and activated carbon. Heating the mixture broke the polymer’s chemical bonds in a short time, Live Science reported.
They then exposed the sample to air. Moisture in the air helped convert the material into terephthalic acid (TPA), which can be processed into more valuable products.
Co-author Yosi Kratish said, “What is particularly interesting is that we used moisture from the air to break down the plastic, achieving an exceptionally clean and selective process.”
The team tested the method on mixed plastic waste and found it selectively targeted polyester materials, so pre-sorting wasn’t necessary. The technology worked on plastic bottles, t-shirts, and colored plastics, breaking them down into TPA.
“When we added more water, the system failed. It turned out that the moisture naturally present in the air was optimal,” Kratish said.
The next step is adapting the process for large-scale industrial use.
Lead author Navin Malik said, “Our technology has the potential to significantly reduce plastic pollution, lessen plastic’s impact on the environment, and promote a circular economy where materials are reused rather than discarded. This demonstrates how innovative chemistry can address global problems in harmony with nature.”
Researchers published their findings in the journal Green Chemistry.
The problem of plastic waste is getting worse. More than half of the plastic in the world was produced after the year 2000. According to the European Environment Agency, annual global plastic production could double by 2050.
To date, only 9 percent of the world’s plastic has been recycled. The remainder creates environmental and health risks: plastic waste washes into the ocean, harms wildlife, and breaks down into microplastics that can enter the human body.
