Chemistry Professor and Student Publish Article on Plastics Recycling

Alumna Ashley Pavia ’21 and Dr. Alessandra Leri, Professor of Chemistry, have published an article on plastics recycling in the Journal of Chemical Education. The paper, “Analysis of Plastic Waste for Sorting in Recycling Plants: An Inquiry-Based FTIR Spectroscopy Experiment for the Organic Chemistry Laboratory,” describes how sophomore-level organic chemistry students can use infrared (IR) spectroscopy to explore the fate of plastic waste.

Problems associated with modern recycling practices have been featured in the news lately, particularly after China’s 2018 ban on importing foreign recyclables, a decision driven largely by unmanageable impurities in recycled waste streams. In Leri and Pavia’s experiment, students use IR spectroscopy to determine the plastic resin types in the various components of waste containers; for example, a bottle, its label, and its lid. The organic chemistry students who perform the experiment at MMC supply their own samples of waste containers and have reported a fascinating array of results, often showing three or more different resin types composing a single container.

Leri and Pavia were inspired to begin this work by a field trip to the SIMS Municipal Recycling Plant in Brooklyn four years ago, when Pavia was a student in Prof. Leri’s first-year seminar on NYC: The Urban Ecosystem. At the recycling facility, the class learned that shrink-wrapped plastic containers (on which the label enshrouds the entire bottle) often cannot be recycled. The labels are frequently made of a different plastic type than the underlying bottle, and this confuses the IR-based sensors in the plant that automate recycling–and make it economically viable. One thing every consumer can do to help is to slice off the full-bottle labels on plastic containers before putting them in the recycling bin—this makes it more likely that the container will be recycled. The labels themselves should be placed in the trash.

Ashley Pavia graduated in May 2021 with a double major in Biology and Urban and Environmental Sustainability. During her undergraduate career at MMC, she conducted research in Prof. Leri’s laboratory for three years. She analyzed dozens of test samples to validate the plastics experiment prior to its implementation in MMC’s Organic Chemistry II lab, CHEM 320. Ashley is now pursuing a Ph.D. in Oceanography at the University of Delaware.