Turning mixed plastic waste into clean hydrogen fuel
TECHNOLOGY
A discarded bottle, shopping bag or a car part can remain in landfill or elsewhere in the environment long after its useful life comes to an end. Recycling it remains a challenge because most systems require different types to be separated first, which is both expensive and labour-intensive. As a result, plastic recycling rates remain low. However, that could all be about to change.
Researchers co-led by the University of California Los Angeles’ Samueli School of Engineering and Ewha Womans University in South Korea have demonstrated a chemical process that converts a mixture of three widely used plastics into high-purity hydrogen fuel. And the process operates at substantially lower temperatures than conventional gasification and stores the carbon as calcium carbonate — a solid mineral — instead of it being released to the atmosphere as pollution.
The findings, published in Proceedings of the National Academy of Sciences, outline an alkaline thermal treatment in which heated sodium hydroxide reacts with organic material to produce hydrogen. In a single reactor, the process treats mixed polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP) without requiring the plastics to be pre-sorted. The resulting hydrogen is better than 90% purity.
Next up is to prove it works commercially, which, say researchers, will require further improving its performance.
“By reducing the sorting costs and process complexity that have been major barriers to commercialisation, this technology has the potential to become a next-generation core technology that supports both the hydrogen economy and the circular economy,” says study co-corresponding author Woo-Jae Kim, a professor of chemical engineering and materials science at Ewha.
ABOVE An illustration of a treatment process that transforms mixed plastic waste into a biomass-like hydrogen source, enabling hydrogen production without atmospheric pollution
PHOTO Younghee Lee/CUBE3D Graphic
This is an exciting development in plastic waste management and clean energy research. Converting mixed plastics into high-purity hydrogen without pre-sorting could help reduce recycling costs, while storing carbon as calcium carbonate offers an interesting environmental benefit. The next important step will be proving that the process can operate efficiently at commercial scale. Innovations like this offer promising possibilities for a more circular economy. Readers interested in other practical resources can explore local business and service information.