Plasma-Based Plastic Depolymerization

Plastics waste is a growing environmental concern. Because plastics do not naturally decay away, it tends to build up in the environment. Via physical processes such as weathering and sun driven photochemical degradation, macroscopic plastics degrade into smaller particles making the more chemically active and mobile, giving rise to the emission of toxins such as dyes or incorporation into the food chain. It is unknown what are the health effects of the metabolic uptake of microplastics by the human body. Nearly 400 million metric tons of plastics are generated each year with less than 10 percent recycled. Recycling is costly and processes such as pyrolysis are energy and maintenance intensive and can give rise to gaseous waste products that themselves are quite harmful to the environment. Nonthermal plasma treatment offers the possibility of depolymerization of plastics waste and ultimately upcycling resulting monomers into high value products. In this work we present results of a depolymerization study of plasma-treated microplastics in solution tracking the production of products and water chemistry over time. Depolymerization mechanisms are also proposed.