Oak Ridge Lab Converts Polyethylene Waste to Fuel Using Low-Temperature Molten Salts

Key points

• The new process converts polyethylene waste into fuels at temperatures below 200 degrees Celsius, significantly lower than conventional pyrolysis methods that require 450 to 500 degrees Celsius.
• The method utilizes molten salts containing aluminum chloride, which act as both the reaction medium and the catalyst, eliminating the need for precious metal catalysts, organic solvents, or external hydrogen.
• Laboratory experiments achieved a gasoline yield of approximately 60%, with simpler polymer chains producing gasoline-like compounds and more complex chains generating diesel-like products.
• The aluminum sites in the molten salt become strongly acidic, breaking down long carbon chains into smaller hydrocarbon molecules through a mechanism involving positively charged carbon atoms.
• A major drawback is the molten salt's tendency to absorb water, which destabilizes the system; researchers are exploring halogens or carbon-based materials to improve containment and processing stability.

Background

This development follows a trend in 2026 of finding novel uses for plastic waste, including converting PET plastic into edible proteins for space missions and transforming PVC into engine lubricants. The current research builds on decades of molten salt studies at Oak Ridge National Laboratory, originally focused on nuclear reactor applications, now applied to polymer upcycling.

Why it matters

This approach offers a potential pathway to convert abundant, difficult-to-recycle plastic waste into valuable fuel products without relying on costly or scarce materials. If scaled successfully, it could reduce environmental impact and create new economic opportunities from consumer waste streams.

What to watch

Researchers are working to overcome the water sensitivity issue by developing better containment methods using halogens or carbon-based materials. The team has also applied for a patent on the method, aiming to move from laboratory experiments to industrial-scale processing.