New research may offer a way to keep single-use plastics such as grocery bags, bottles, straws and food containers out of landfills. But instead of transforming these hard-to-recycle products back into useful plastics, the new technique reduces the plastics back down to the petroleum oil used to make them in the first place, reports Molly Taft for Gizmodo. The resulting oil can then find a new life as fuels or lubricants.
Apart from keeping single-use plastics out of landfills, if implemented at a large scale the new method could reduce the world’s oil demands. Per Gizmodo, plastic manufacturing is projected to comprise half of the world’s oil demand by 2050.
Researchers say their process, described in a paper published last week in the journal Science Advances, works best on plastics called polyolefins, which are used to make products we are often told can’t be recycled, such as plastic bags.
The basic concept is to heat the plastics to break their chemical bonds and reduce them down to their constituent parts. What’s new is that the team behind this research has found a way to achieve this at much lower temperatures than ever before, which makes the process more energy efficient and cost effective.
“This is the first technology that’s able to take the most difficult plastics and recycle them into something really useful,” Dionisios Vlachos, a chemical engineer at the University of Delaware and co-author of the paper, tells Jordan Golson of Inverse. “It’s the best way to recycle single-use plastics and packaging like polyethylene and polypropylene.”
Using heat to break down plastics is called pyrolysis, and Vlachos tells Gizmodo that most prior research focuses on processes that require temperatures ranging from 752 to 1,472 degrees Fahrenheit to work. Vlachos says his team’s technique can get the job done at just 437 degrees, and that the end result is “nearly ready-to-use fuels for cars, trucks, or airplanes and lubricants.”
The special sauce in this new method is its catalyst, which is a combination of zeolites (minerals mostly made up of aluminum and silicon) and metal oxides including platinum and tungsten, per the paper.
“Alone these two catalysts do poorly. Together, the combination does magic, melting the plastics down and leaving no plastic behind,” says Vlachos in a statement.
According to Inverse, the method can convert up to 85 percent of the original material into useful oil. Vlachos tells Inverse he estimates around 300 half-liter water bottles could produce enough oil to make a gallon of gasoline, and two pickup truck beds full of plastic bottles might fill a car’s gas tank.
Vlachos and his co-authors have filed a provisional patent on their technique and its catalyst, but he says more work is needed to translate the method to industrial-scale use.
“We need to take action on the plastics problem and develop technologies and policies to eliminate it from the environment,” Vlachos tells Gizmodo. “Research takes 10-plus years before it becomes useful. Investing in this field now is a priority.”