Ames National Laboratory team transforms plastic waste into fuel

When Yi-Yu Wang pictures the future, she hopes for a day when someone can just pop an empty water bottle in their car’s tank when running low on gas in order to deliver the energy it needs to keep driving.

A graduate research assistant in the Ames National Laboratory-led Institute for Cooperative Upcycling of Plastics (iCOUP), Wang and other researchers are studying ways to break down non-recyclable plastic and convert it into chemicals and other materials.

While the team hasn’t quite made that breakthrough yet, the work they’re doing now could provide both a solution to the problem of growing plastic waste and products comparable to diesel, aviation fuel, lubricating oils and more.

“I think it’s very exciting,” Wang said. “You’re thinking you’re doing real life chemistry, not just … something in the lab, but you’re actually changing the world.”

Funded by the U.S. Department of Energy, iCOUP is an Energy Frontier Research Center made up of scientists from the Ames National Laboratory and six other institutions across the U.S.

The Ames team has developed a one-step process that uses a catalyst, or a substance that speeds up a chemical reaction without being consumed in the process, to break down the polymers that make up plastic and convert them into specific chemicals.

Aaron Sadow, an Iowa State University professor and director of iCOUP, said half of the 350-400 million tons of plastic made around the world each year cannot be recycled, and are either put in a landfill or burned. Having the ability to turn items like packaging materials and other single-use plastics into things of value, like fuel and chemicals, would have a large ecological impact while also garnering economic benefits.

“Plastics are just a part of our manufacturing and energy economy,” Sadow said. “They’re an important part and they’re one that keeps getting bigger and bigger, but in the end, we’ve got environmental and energy challenges, and the only way to solve those is with technologies that can be profitable and appealing to people.”

Wang said the plastic polymers are added to a reactor and introduced to the catalyst, where they are heated, then the chemical created by the polymers breaking apart in a certain way is condensed and collected.

Wang said this process allows them to collect the product while the reaction is occurring, making it faster and simpler than other processes that require refining and other steps. The catalysis used by the team is able to derive specific chemicals from the polymers, Sadow said, instead of the polymer breaking into many different parts that must be separated in an expensive process to create what’s needed.

Once products have been made from the waste, the lab will send it off to different locations to be tested and further studied to see how they act and compare to the materials they could serve as substitutes for.

What’s been found so far when comparing the lab-made diesel and lubricants to their traditional counterparts, Sadow said, is that they have advantages. The lubricant they’ve sent to Texas A&M University has been found to be less viscous than synthetic lubricants but it works just as well, and the diesel product is cleaner than traditional diesel.

Conversions are being made at a small scale right now, but the team is working on being able to convert more material with larger reactors and create continuous flow in their reactors. It will take more time and research before it can be commercialized, Sadow said, but eventually they could manufacture things like lubricant themselves or it could be picked up by a company.

Rich Iverson, fleet support manager for the City of Ames, said he’s spoken with the team about eventually utilizing the fuel in the city’s biodiesel program — a pilot program started in 2019 that has equipped some of the city’s snowplow trucks with technology to run almost entirely on biodiesel, cultivated from soybeans and animal fats.

One issue with these biodiesel products is that they start to congeal in colder weather, Iverson said, so the truck has to use traditional diesel to warm up enough for the biodiesel to be usable and switch back to it when needed. Depending on how long the truck is in operation, it will run on around 90% biodiesel.

“If we had a clean diesel fuel from plastic that would have gone to the landfill … for a good price, that would mean the truck is burning renewable fuel all the time,” Iverson said.

In order for the city to start using the new fuel, Iverson said the team would need to show that the fuel is compatible with regular diesel, and the city would need a couple hundred gallons to test in the trucks. Next steps would also include pricing, as it would need to be competitive to be viable.

Sadow said students in the group have started a spin-off company to market these fuels and are working on connecting with venture capital firms and applying for grants to fund the development of a pilot plant in order to expand and commercialize operations. For the many small towns in Iowa that rely on diesel and generate a lot of plastic waste, he said supporting these efforts would be a “no-brainer.”

It’s important for people to realize the enormity of all of the plastic waste that goes into a landfill or incinerator rather than turned into anything useful, Iverson said, and that this avenue of addressing the problem, even at a local level, is worth celebrating.

“Anytime somebody is going to do something, making a positive impact on our environment, on the quality of life in the long term, and if they’re doing it in a way that’s not going to break the bank, then I think that’s good,” Iverson said. “That’s really good — makes me proud to be a graduate of Iowa State.”