Researchers from Zhejiang University, in collaboration with Cardiff University and the University of Tokyo, have developed a catalyst free recycling process that converts plastic waste into valuable industrial chemicals using only water and oxygen.
The new method breaks down hard to recycle plastics such as polyethylene (PE) and polypropylene (PP) without using expensive or toxic catalysts. Instead, molten plastic is heated and stirred in water, forming microscopic droplets where naturally generated hydroxyl radicals break long plastic chains into smaller, useful molecules.
The process converts mixed and contaminated plastic waste into organic acids, which are widely used in pharmaceuticals, food additives, and biodegradable materials. In laboratory tests, nearly all polyethylene was converted, with around 69% transformed into valuable short chain diacids.
Unlike many existing recycling technologies, the method can process real world plastic waste including plastic bags, gloves, bottle caps, and even discarded tyre rubber without extensive sorting. It also works with tap water and seawater, making it suitable for a wide range of locations.
Researchers successfully demonstrated the process in a larger 300 gram reactor, indicating strong potential for industrial-scale applications. Because it eliminates catalysts, the technique could reduce recycling costs, simplify operations, and minimise environmental impacts associated with conventional chemical recycling.
The team believes the technology could help shift plastic waste management towards a circular economy by turning discarded plastics into high value chemical feedstocks instead of sending them to landfills or incinerators.