Every year, the world throws away hundreds of millions of tons of plastic. Only 9% of it gets recycled. The rest ends up in landfills or is burned, releasing carbon dioxide into the air. That could change thanks to a new process developed by researchers at UCLA and Ewha Womans University in South Korea.
The team created a method called Alkaline Thermal Treatment, or ATT for short. It converts a mixture of the three most common plastics directly into hydrogen fuel with purities over 90% — without requiring the plastics to be sorted by type first.
"We are solving two urgent global problems at the same time," said Ah-Hyung "Alissa" Park, a professor of chemical engineering at UCLA and one of the study's lead researchers. "Plastic waste is accumulating at alarming rates, and clean hydrogen is essential for decarbonizing energy. This technology tackles both of these challenges."
Most recycling requires plastics to be separated by type — PET bottles, polyethylene bags, polypropylene containers — a step that is expensive and labor-intensive. The new ATT process skips that entirely. In lab experiments, the researchers mixed all three plastic types together in a single reactor with sodium hydroxide and applied heat. The reaction released hydrogen gas while locking carbon away as a solid mineral instead of releasing it as carbon dioxide. More than 75% of the carbon from the original plastic ended up trapped in solid form. Less than 13% appeared as gas, and almost none escaped into the atmosphere.
The process also works at much lower temperatures than existing methods. Traditional steam gasification requires extremely high heat — ATT operates 300 to 400 degrees Celsius cooler, which means it could require less energy to run.
The researchers adapted ATT from an earlier method they created to turn seaweed into hydrogen. Polyethylene and polypropylene — the plastics used in grocery bags and food containers — were initially harder to break down because they contain only carbon and hydrogen with no oxygen. The team solved this by briefly heating those plastics in air before the main reaction, which creates reactive spots where the alkaline treatment can work.
The hydrogen produced can be used as a clean fuel, while the captured carbon can be converted into calcium carbonate, a mineral used in industries like cement and paper that have traditionally released large amounts of carbon dioxide.
"By reducing the sorting costs and process complexity that have been major barriers to commercialization, this technology has the potential to become a next-generation core technology that supports both the hydrogen economy and the circular economy," said Woo-Jae Kim, a professor at Ewha Womans University and the study's other lead researcher.
The work was published in the journal Proceedings of the National Academy of Sciences. The researchers say they still need to optimize the process and check whether it can work economically on a large scale. But the early results suggest a future where plastic waste might power cars, homes, and factories — instead of piling up in trash dumps.