UCLA Researchers Develop Process to Convert Mixed Plastic Waste Into Hydrogen Fuel

Alkaline Thermal Treatment: Bypassing the Sorting Crisis

Global plastic recycling remains trapped in a low-efficiency cycle. According to findings reported by Phys.org, only 9 percent of discarded plastic is successfully recycled. The vast majority—79 percent—is relegated to landfills, while another 12 percent is incinerated, a process that releases carbon dioxide into the atmosphere. The primary barrier to higher recycling rates is the necessity of sorting plastics by type, a labor-intensive and costly requirement that frequently renders the process less economical than producing new plastic from fossil resources.

The new method, known as alkaline thermal treatment (ATT), addresses this bottleneck by processing a mixture of the three most common plastics—polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP)—in a single reactor. As UCLA’s newsroom reported, this approach operates at temperatures far below conventional gasification. By introducing a thermal oxidation pretreatment, researchers can activate chemically inert plastics like PE and PP, allowing them to decompose efficiently alongside PET.

“We are solving two urgent global problems at the same time,” said co-corresponding author Ah-Hyung “Alissa” Park, the Ronald and Valerie Sugar Dean of UCLA Samueli and a professor of chemical and biomolecular engineering. “Plastic waste is accumulating at alarming rates, and clean hydrogen is essential for decarbonizing energy. This technology tackles both of these challenges in a creative and scalable way.”

For more on this story, see This New Process Turns Plastic Trash Into Clean Fuel Instead of Pollution.

Ah-Hyung “Alissa” Park, the Ronald and Valerie Sugar Dean of UCLA Samueli and a professor of chemical and biomolecular engineering

Carbon Capture and Hydrogen Purity

Beyond its ability to handle unsorted waste, the ATT process functions as a carbon-neutral method. During the reaction, sodium hydroxide captures the carbon released from the plastic, converting it into a solid mineral, sodium carbonate.

The resulting hydrogen gas achieves a purity level exceeding 90 percent. Unlike earlier low-temperature approaches that were limited to oxygen-containing plastics like PET, the modified ATT process successfully processes the entire spectrum of common household plastic waste. Gizmodo highlighted that this advancement moves the field away from the energy-intensive demands of high-temperature gasification, which typically requires extreme temperatures and pressures to handle mixed streams.

Future Challenges for Scalability

Despite the success of these laboratory and pilot-scale demonstrations, significant hurdles remain before these technologies can be deployed at a municipal level. The ATT process, while promising, currently requires further optimization to transition from precision laboratory settings to large-scale recycling plants. Experts emphasize that the long-term economic viability of such chemical recycling methods must be rigorously tested against the fluctuating costs of fossil fuel-derived plastics.

As the global demand for hydrogen as a clean energy source grows, researchers continue to look for ways to make these conversion processes more energy-efficient. The core challenge remains the same: transforming a ubiquitous, durable material into a renewable resource without creating new environmental costs in the process.