Recycling bio-plastics may not be a mission impossible

The Universities of Birmingham and Bath have developed a faster and more efficient recycling method specifically for bio-plastics.

A group of researchers reports that their chemical recycling method not only speeds up the process, it can also be converted into a new product – a biodegradable solvent. This solvent can serve a wide variety of industries, such as cosmetics and pharmaceuticals.

The process relies on a zinc-based catalyst as well as methanol to break down consumer plastics and produce the ‘green solvent’, called methyl lactate. It takes several months for bio-plastics to degrade, notes lead author Luis Román-Ramírez of the University of Birmingham’s School of Chemical Engineering.

His team tested the new recycling method on three different products; a disposable cup, some 3D printer waste, and a children’s toy. They found the cup was most easily converted to methyl lactate at lower temperatures, but even the bulkier plastic in the children’s toy could be converted using higher temperatures.

‘We were excited to see that it was possible to obtain high quantities of the green solvent regardless of samples’ characteristics due to colorants, additives, sizes and even molecular weight,’ says Román-Ramírez.  

And he adds: ‘Our technique breaks down the plastics into their chemical building blocks before ‘rebuilding’ them into a new product, so we can guarantee that the new product is of sufficiently high quality for use in other products and processes.’

The innovative work has been published in the journal Industrial & Engineering Chemistry Research.