Chemists from Northwestern University have developed a solvent free system based on an inexpensive novel catalyst which can break apart the bonds in polyethylene terephthalate (PET), the most common of the polyester family of plastics.
After breaking apart the bonds, the system then relies on the trace amount of moisture in ambient air to convert the broken down PET into monomers which the team envision could be recycled into new PET products or other valuable materials. The non-toxic and inexpensive system provides a safer more environmentally friendly method for plastic recycling paving the way towards a circular plastics economy.
"The U.S. is the number one plastic polluter per capita, and we only recycle 5% of those plastics," said Yosi Kratish, the study's co-corresponding author. "There is a dire need for better technologies that can process different types of plastic waste. Most of the technologies that we have today melt down plastic bottles and downcycle them into lower-quality products.
"What's particularly exciting about our research is that we harnessed moisture from air to break down the plastics, achieving an exceptionally clean and selective process. By recovering the monomers, which are the basic building blocks of PET, we can recycle or even upcycle them into more valuable materials."
During analysis the system proved effective at breaking down real-world materials such as bottles, shirts, and mixed plastic waste into valuable terephthalic acid (TPA), the highly valuable precursor to polyesters.
The team plan to scale the system up for industrial use, aiming to ensure it can handle large amounts of PET waste.
"Our technology has the potential to significantly reduce plastic pollution, lower the environmental footprint of plastics and contribute to a circular economy where materials are reused rather than discarded," said Naveen Malik, the study's first author. "It's a tangible step toward a cleaner, greener future, and it demonstrates how innovative chemistry can address global challenges in a way that aligns with nature."