Plastic Recycling Gets a Breath of Fresh Air

SEATTLE (Scrap Monster): Harnessing moisture from air, Northwestern University chemists have developed a simple new method for breaking down plastic waste.

The non-toxic, environmentally friendly, solvent-free process first uses an inexpensive catalyst to break apart the bonds in polyethylene terephthalate (PET), the most common plastic in the polyester family. Then, the researchers merely expose the broken pieces to ambient air. Leveraging the trace amounts of moisture in air, the broken-down PET is converted into monomers — the crucial building blocks for plastics. From there, the researchers envision the monomers could be recycled into new PET products or other, more valuable materials.

Safer, cleaner, cheaper and more sustainable than current plastic recycling methods, the new technique, published in the journal Green Chemistry, offers a promising path toward creating a circular economy for plastics.

“The U.S. is the number one plastic polluter per capita, and we only recycle 5% of those plastics,” said Northwestern’s 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.”

“Our study offers a sustainable and efficient solution to one of the world’s most pressing environmental challenges: plastic waste,” said Naveen Malik, the study’s first author. “Unlike traditional recycling methods, which often produce harmful byproducts like waste salts and require significant energy or chemical inputs, our approach uses a solvent-free process that relies on trace moisture from ambient air. This makes it not only environmentally friendly but also highly practical for real-world applications.”

An expert in plastic recycling, Kratish is a research assistant professor of chemistry at Northwestern’s Weinberg College of Arts and Sciences. Kratish co-led the study with Tobin J. Marks, the Charles E. and Emma H. Morrison Professor of Chemistry at Weinberg and a professor of materials science and engineering at Northwestern’s McCormick School of Engineering. At the time of the research, Malik was an postdoctoral fellow in Marks’ laboratory; now he is a research assistant professor at the SRM Institute of Science and Technology in India.

 Courtesy: www.news.northwestern.edu