Researchers develop low-temperature molten-salt method to turn polyethylene waste into fuel

Oak Ridge National Laboratory researchers have demonstrated that aluminum-based molten salts can efficiently upcycle polyethylene, a common plastic, into liquid fuels resembling gasoline and diesel. The salts serve simultaneously as solvent and catalyst, cleaving polymer chains at temperatures under 200 °C, far lower than the 450-500 °C needed for conventional pyrolysis. The process yields roughly 60% gasoline without noble-metal catalysts, organic solvents, external hydrogen, or chemical initiators.

Detailed analyses using neutron scattering, soft X-ray spectroscopy and computational modeling revealed acidic aluminum sites that attack the polymer, with product distribution dependent on polymer chain complexity. The findings, published in the Journal of the American Chemical Society, are backed by a pending patent and could enhance U.S. energy security if scaled up. Researchers note that moisture sensitivity of the salts remains a challenge that will be addressed in future work.