China Develops Low-Cost Method To Convert Plastic Waste Into Hydrogen Fuel

Overcoming the Sorting Barrier in Plastic Recycling

The global reliance on plastic has created a significant disposal crisis, with 79 percent of plastic waste ending up in landfills and 12 percent being incinerated. A primary hurdle in recycling is the labor-intensive requirement to sort materials by type, which is often more expensive than producing new plastic from fossil resources. According to researchers at Ewha Womans University, discarded plastics are frequently contaminated with food, labels, and dyes, or combined in complex, multilayer packaging that makes traditional recycling inefficient.

To address this, the new Alkaline Thermal Treatment (ATT) process allows for the conversion of mixed plastic streams—specifically polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP)—within a single reactor. This eliminates the need for the rigorous sorting that has historically kept global recycling rates stagnant at approximately 9 percent.

Chemical Mechanics of the ATT Process

The ATT method functions by mixing plastic waste with sodium hydroxide (NaOH) and heating the mixture, which triggers a reaction that releases hydrogen gas. Unlike traditional gasification, which requires extreme temperatures and high pressure, the ATT process operates at lower temperatures—around 400 degrees Celsius, or 752 degrees Fahrenheit—making it significantly less energy-intensive.

While PET breaks down easily, PE and PP are chemically inert due to their stable carbon-hydrogen bonds. To ensure these materials also decompose, the research team introduced a thermal oxidation pretreatment. As reported by Chemistry World, this involves exposing the plastic to mild heat and oxygen for up to 50 hours to create reactive weak spots in the polymer chains.

Environmental Impact and Carbon Sequestration

The process is designed to be cleaner than industrial steam reforming, which currently produces approximately 10kg of carbon dioxide for every 1kg of hydrogen generated. By utilizing sodium hydroxide as a reagent, the ATT method captures carbon within the reaction, preventing it from being vented as greenhouse gas.

The research team highlights the dual benefit of the technology. According to a study involving the Shanghai Advanced Research Institute and Fudan University, the selectivity of the process allows for the production of specific hydrocarbon ranges, potentially creating aviation fuel from polyolefins, which account for over 60 percent of plastic waste.

Scaling Challenges and Future Viability

Despite the successful laboratory results, the technology faces significant hurdles before reaching municipal adoption. Current trials have been conducted on a scale of less than 1 gram, with the team now moving toward 100-gram tests. Experts note that while the approach is a welcome addition to the net-zero transition, the economic viability of scaling the process for industrial recycling plants remains to be tested.

There are also questions regarding the ultimate environmental “greenness” of the fuel produced. Furthermore, the handling of large quantities of sodium carbonate byproduct will require new commercial applications to be sustainable at scale.