A groundbreaking technique for recycling polystyrene (PS) was developed by a team of chemical engineers from the University of Bath in the UK and Worcester Polytechnic Institute in Massachusetts, USA. Their method could make recycling PS both economically viable and energy efficient, revolutionizing the way this polymer is handled.
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Research Details
In a recent paper, published in Chemical Engineering Journal, this new process uses pyrolysis to decompose PS into its basic components, which can then be reformed into new products. This approach could significantly boost the recycling rate of polystyrene, since less than 5 % is currently recycled, according to the study.
Challenges with Current Recycling Methods
The challenge with Polystyrene recycling has traditionally been the material’s degradation through repeated treatments, which diminishes its strength and flexibility. Most recycling centers do not accept PS due to the specialized facilities it requires to be recycled and the high transport costs due to its bulk.
The Polystyrene Recycling Process
This study’s pyrolysis method addresses these issues by subjecting PS to temperatures above 450 degrees Celsius in an oxygen-free environment (preventing combustion) and breaking it down into monomers. These monomers can be purified and reformed into new PS. Producing 1 kilogram of new material using this method requires less than 10 megajoules of energy—about the same as powering a microwave for 30 minutes.
With this process, 1 kilogram of used PS can produce 600 grams of 99 % pure monomer-grade styrene for new PS production, thus reducing reliance on fossil fuels.
Policy Implications and Future Outlook
Researchers also highlight the potential for policy measures to incentivize PS recycling, which would further enhance the economic viability of their process. Encouraging consumers to recycle PS or divert it from landfills could provide additional benefits and drive widespread adoption of this innovative recycling technique.
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