Researchers have demonstrated a chemical process that can convert a mixture of common plastics directly into high-purity hydrogen fuel, according to ScienceDaily. The method also keeps much of the carbon from escaping into the air by turning it into a solid mineral form.
The study, co-led by scientists at the UCLA Samueli School of Engineering and Ewha Womans University in South Korea, used a technique called alkaline thermal treatment, or ATT. In lab tests, the process handled mixed polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP) without requiring the plastics to be sorted first.
According to the researchers, the hydrogen produced was more than 90% pure, and the process worked at temperatures 300-400 degrees Celsius below those used in traditional steam gasification. They added a brief thermal oxidation pretreatment to help PE and PP react more efficiently under the alkaline conditions.
The team also found that sodium hydroxide captured carbon released during the reaction and converted it into sodium carbonate. After the process, more than 75% of the carbon in the plastic had ended up in stable carbonate compounds or liquid organic residues, while less than 13% entered the gas phase.
The researchers say the technology is promising but not ready for commercial use yet. More work is needed to improve the process and determine whether it can produce hydrogen economically at scale.
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