Hydrogen produced from mixed plastic waste

July 16, 2026

Scientists have developed an innovative recycling technology that transforms mixed plastic waste into high-purity hydrogen fuel without the need for complex sorting. The breakthrough process, known as Alkaline Thermal Treatment (ATT), could significantly reduce plastic pollution while supporting the transition to cleaner energy.

The research was conducted by scientists from the UCLA Samueli School of Engineering and Ewha Womans University in South Korea. Their findings demonstrate that mixed plastic waste can be converted into hydrogen using a single-reactor system, eliminating one of the biggest barriers to efficient plastic recycling.

Single-reactor technology handles mixed plastic waste

Traditional recycling systems require plastics to be separated by type before processing, making recycling expensive, slow, and inefficient. The newly developed ATT process bypasses this requirement by treating three of the world's most widely used plastics together:

- Polyethylene terephthalate (PET)
- Polyethylene (PE)
- Polypropylene (PP)

By processing these materials in one reactor, the technology simplifies recycling operations and could improve recovery rates for plastics that currently end up in landfills or incinerators.

According to Ah-Hyung "Alissa" Park, Ronald and Valerie Sugar Dean of UCLA Samueli and professor of chemical and biomolecular engineering, the innovation addresses two critical global challenges simultaneously.

Plastic pollution continues to grow worldwide, while clean hydrogen is becoming increasingly important for decarbonizing transportation, manufacturing, and energy production. The ATT process offers a scalable solution capable of tackling both issues at once.

Solving one of recycling's biggest challenges

Mixed plastic waste has long frustrated recycling systems because different polymers require different treatment methods. As a result, most discarded plastics are never recycled.

Globally, nearly 79% of plastic waste is sent to landfills, around 12% is incinerated, and only 9% is successfully recycled into new products.

The new chemical process changes that equation by converting unsorted plastic mixtures directly into valuable hydrogen fuel while preventing carbon dioxide emissions during the reaction.

How alkaline thermal treatment produces hydrogen

ATT works by heating plastic waste in the presence of sodium hydroxide, triggering chemical reactions that release hydrogen gas.

The technology was originally designed to extract hydrogen from marine biomass such as seaweed. Researchers later adapted the process to handle synthetic polymers after recognizing its potential for plastic recycling.

Early experiments showed that PET plastics degraded efficiently, while PE and PP proved much more resistant because of their stable carbon-hydrogen bonds.

To overcome this limitation, the team introduced a thermal oxidation pretreatment. During this stage, the mixed plastics are briefly heated in air, allowing oxygen to create reactive sites along the polymer chains. These weak points enable the ATT process to break down all three plastic types much more effectively.

High-purity hydrogen without carbon emissions

Following pretreatment, the mixed plastic feedstock is processed inside a single reactor, producing hydrogen with a purity exceeding 90%.

Unlike conventional gasification technologies that require much higher operating temperatures, ATT functions at approximately 400°C (752°F), reducing overall energy consumption.

Another key advantage is its carbon management strategy. Instead of releasing greenhouse gases, the sodium hydroxide captures carbon from the plastics and converts it into sodium carbonate, a stable solid mineral.