A new way of thinking about recycling plastics has allowed scientists to recycle PVCs into useful products
Spotted: In 2019, the production volume of PVC, or polyvinyl chloride, in the United States reached 7.2 million metric tonnes. However, although PVC is technically recyclable, it is the least post-consumer recycled plastic in the country. Now, a research team from the University of Michigan, led by Anne McNeil and Danielle Fagnani, has discovered a way to chemically recycle PVC into usable material.
One reason PVC is not recycled is that, while most plastics are recycled by melting and then reforming them, PVC tends to leach plasticiser – one of its primary components – when heated. This plasticiser can then enter other plastics and make them unusable. Hydrochloric acid (HCl) also leaches out of the heated PVC, corroding recycling equipment and injuring workers. So, instead of heat, the researchers turned to electrochemistry.
Introducing a negative charge into the system broke the carbon-chloride bond and resulted in a negatively charged chloride ion, and the formation of hydrochloric acid. But using electrochemistry allows the researcher to control the rate at which electrons are introduced – and how quickly hydrochloric acid is produced. The measured release of HCl reduces the risks associated with recycling PVC. Then, the recovered HCl can be used by industries as a reagent for other chemical reactions. Meanwhile the chloride ions can be used in agricultural and pharmaceutical components
Written By: Lisa Magloff