Chemists have discovered a way to use light and oxygen to upcycle polystyrene into Benzoic acid, a product usually stocked in chemistry labs, and used in food preservatives, fragrances, and other common products.
Common products such as Styrofoam egg cartons, hard plastic compact disc cases, red drinking cups etc. are composed of polystyrene, which makes up a third of landfill waste worldwide. The team at Cornell University, New York led by Erin Stache, assistant professor of chemistry and chemical biology found that the reaction can take place in a sunny window. Stache mentioned that the discovery is mild and climate-friendly which is in line with her lab’s mission to tackle environmental concerns through chemistry.
The process has also proven to be tolerant of additives inherent in a flow of consumer waste, including dirt, dyes, and other types of plastics. This was tested by using three items – a white coffee cup lid, Styrofoam, and a clear lid. A black coffee cup lid was also used however, it degraded less efficiently due to the presence of black dyes with inhibit light penetration. The team also reported that a large-scale setup, would work as efficiently as the small-scale setup in the lab, which proves its efficiency for the possibility of commercialising it to address waste streams.
Their paper, "Chemical Upcycling of Commercial Polystyrene via Catalyst-Controlled Photooxidation" has been published in the Journal of the American Chemical Society.