plastic waste packaging

Low-carbon plastic recycling process developed using ‘supercritical’ water

Image credit: University of Birmingham

Researchers have developed a new process for recycling mixed plastic packaging that improves upon current methods by delivering a greater proportion of high-value recycled plastic with less emissions and no solvent residues.

The team from the University of Birmingham used water under incredibly high pressure and temperature called ‘supercritical’, where its properties and operational behaviour are completely different from ambient/hot water.

Supercritical water can be a solvent for all organic materials including plastics. Its gas-like penetration power makes it a superior medium to decompose mixtures of complex waste plastics into value-added materials, which are feedstock for manufacturing new plastics.

The team wants to further develop the process, dubbed CircuPlast, to improve the conversion of non-recyclable end-of-life plastics into high-value chemicals for use as feedstock for the plastics industry.

The process has been licensed to engineering consultants Stopford. The firm’s technology & innovation director Dr Ben Herbert said: “This agreement enables Stopford to fast-track the development of the CircuPlast technology to meet the plastics management and sustainability requirements of multiple industry sectors.”

David Coleman, CEO of University of Birmingham Enterprise, said: “The growth of plastics production has long outstripped the capacity for recycling, with the UK alone producing over two million tonnes of plastic packaging waste each year, of which just over half is recycled. We are delighted the university is working with Stopford to deliver a viable way of recycling much more plastic packaging that will help meet sustainability goals.”

CircuPlast will be an eco-friendly technology using ‘supercritical’ water rather than industrial solvents for the repurposing of waste plastics adopting a circular approach. The technology will provide a sustainable alternative to fossil-oil-derived feedstocks with no CO2 emissions in the production or disposal phases.

Lead researcher Dr Bushra Al-Duri, of the University of Birmingham's School of Chemical Engineering, added: “Supercritical water technology represents the next generation for treatment and recycling of ‘stubborn’, complex, and hazardous waste that is currently treated by incineration or sent to landfill. I am looking forward to working with Stopford on the scientific and operational challenges involved in bringing this technology to market.”

CircuPlast is expected to overcome the substantial limitations of existing recycling processes by enhancing recycling rates, enabling an increase in the recycled content of plastics, maintaining functionality, to a level that is currently unachievable using mechanically recovered materials.

Earlier this week, E&T revealed that a waste exporter contracted by Tesco and Sainsbury’s had been breaching UK export regulations when it shipped waste to five sites in Turkey.

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