Project to Enable Plastics to be Recycled Together

Never sure whether you can recycle your milk bottles with your margarine tubs? This problem could be solved in a few years, thanks to a new project led by the University of Bath that will allow a mixture of plastics to be recycled together.

Plastic milk bottles are made from high-density polyethylene (HDPE), whereas margarine tubs are made from polypropylene. These two plastics cannot be recycled together so have to be separated either by householders or at the recycling center, a labor-intensive process that can often mean that plastics ends up in landfill because the batch becomes accidentally contaminated with several types of plastic.

However, the team of scientists and engineers at Bath’s Centre for Sustainable Chemical Technologies and Manchester University, led by Dr. Arthur Garforth at Manchester, is investigating ways of chemically breaking down mixtures of plastics into their constituent molecules which can then be used to manufacture new plastics or other high value products.

Professor Matthew Davidson, Director of the Centre for Sustainable Chemical Technologies (CSCT) at Bath, said: “Currently only about one third of plastic food packaging in the UK is recycled. The UK Government aims to increase that to 75 per cent by 2035.

“Part of this problem is that plastics have to be separated into different types as each type has different properties and they can’t be recycled together.

“Our colleagues in Manchester have already demonstrated a process to recover the chemical value from waste plastics and, together, we aim to develop this further in order to develop new technology for mixed plastics waste.

“This means in the not-too-distant future people will be able to throw all their plastics in the same recycling bin without worrying about separating them.

“This could make a big difference to recycling rates and help us solve the urgent problem of plastic waste.”

This project is one of seven challenges being tackled by a consortium of UK universities and industrial partners led by the University of Bath to develop new catalysts that will enable more sustainable manufacturing and promote a circular economy - where waste materials are reused or recycled into other things instead of simply being thrown away.

The £4.8 million Bath-led consortium is one of three partnerships supported by a £14 million investment into the UK’s Catalysis Hub by the Engineering and Physical Sciences Research Council (EPSRC), which is part of UK Research and Innovation (UKRI).

Other challenges being tackled by the Bath-led consortium include: using the carbon dioxide released by burning fossil fuels to make new fuels or high-value chemicals for the chemical manufacturing industry; making new sustainable plastics from bio-based materials that can be programmed to biodegrade at the end of their useful life; and developing new catalysts from cheap, benign and abundant metals.

Professor Matthew Davidson said: “Most carbon emissions due to human activity are from burning fossil fuels that we’ve dug out of the ground. The carbon dioxide is released into the atmosphere where it stays and contributes to climate change.

“What we want to do is to create a circular economy, where we reduce carbon emissions and capture that which is emitted and incorporate it into new fuels that can be burned again.

“Carbon that can’t be made back into fuel again can be instead be made into other useful products like plastics and pharmaceuticals.

“The Catalysis Hub will design new catalysts to keep these molecules in play for as long as possible, ending the throw-away culture that is currently part of our daily lives.

“We’re really looking forward to leading this multi-disciplinary consortium that brings together the UK’s best scientists and engineers to work on this important global problem.”

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