Plastic waste is accumulating in the oceans, in the soil and even in our bodies. Despite great efforts to recycle plastic products, the actual use of this colourful mix of materials remains a difficult issue. As a result, much of the plastic collected through recycling programmes ends up in landfills.

Researchers at MIT and other institutes have found a better way: A chemical process that uses a cobalt-based catalyst to break down a variety of plastics such as polyethylene (PET) and polypropylene (PP) into a single product, propane.

Propane can then be used as fuel for stoves, heaters and vehicles, or as a feedstock for the manufacture of a variety of products - including new plastics - allowing at least a partially closed recycling loop.

The researchers tested their system on a real example of mixed recycled plastic and obtained promising results. However, further testing with a wider variety of mixed waste streams is needed to determine how much contamination there is from different impurities in the material and how this affects the long-term stability of the process.