Chemists from Northwestern University have developed a new process which can drastically reduce, or even completely bypass, the time-consuming process of pre-sorting mixed plastic waste. Thanks to an inexpensive new nickel-based catalyst, the method can even selectively break down single use polyethylenes and polypropylenes which are responsible for almost two-thirds of worldwide plastic consumption.
Published in the journal Nature Chemistry, the method produces plastic oils and waxes by breaking down the polyolefins, resulting in a material which can be upcycled into high value products such as lubricants, fuels, and candles. Additionally, the method can break down plastic which are contaminated with PVC, a notoriously toxic polymer which makes plastics “unrecyclable”.
"One of the biggest hurdles in plastic recycling has always been the necessity of meticulously sorting plastic waste by type," said Tobin Marks, the study's senior author. "Our new catalyst could bypass this costly and labor-intensive step for common polyolefin plastics, making recycling more efficient, practical and economically viable than current strategies."
"When people think of plastic, they likely are thinking about polyolefins," added Northwestern's Yosi Kratish.
"Basically, almost everything in your refrigerator is polyolefin-based squeeze bottles for condiments and salad dressings, milk jugs, plastic wrap, trash bags, disposable utensils, juice cartons and much more. These plastics have a very short lifetime, so they are mostly single-use.
"If we don't have an efficient way to recycle them, then they end up in landfills and in the environment, where they linger for decades before degrading into harmful microplastics."