Researcher(s)
- Ashley Tolocka, Chemical Engineering, University of Delaware
Faculty Mentor(s)
- Pedro Moura, Center for Plastics Innovation, University of Delaware
Abstract
Several studies have analyzed the decomposition of plastics like ethylene vinyl acetate (EVA),1–2 low-density polyethylene (LDPE),1, 3–4, and other polyolefins (PO)3–4 using hydrogenolysis and hydrocracking of various catalysts to gain selective high-value alkanes products, such as naphtha, diesel or wax/lubricant base-oils. However, such studies primarily concentrate on the pure forms of these plastics, whereas typical single-use packaging materials possess multiple layers of polyolefins. Here, we optimize and investigate the conversion rate of a ruthenium-based hydrogenolysis catalyst supported by titanium dioxide (Ru/TiO2) and hydrocracking using platinum supported on HY zeolite (Pt/HY) for three types of food and biopharmaceutical packaging films.
Inspired by prior literature,1 we tested Pt/HY and different Ru-supported catalysts while varying parameters sensitive to PO hydroconversion (i.e., temperature, H2 pressure, polymer/catalyst ratio, and reaction time).1, 3–4 At optimized conditions of 300 ⁰C, 30 bar H2, 4 h, and 20:1 polymer/catalyst, we obtain the highest yield of desirable liquid products with Ru/TiO2, deconstructing ~75% of a generic-brand freezer bag into ~20% C18-C35 alkanes. The film is a monolayer of an EVA/PE blend, and we find similar results in more complex films (i.e., 5-layer EVA/PE poultry bag film). Pt/HY deconstructs the freezer bag at comparable rates to Ru/TiO2, yielding, on average, ~10% C4 and 20% light naphtha (C5-C6) on average. Our initial findings demonstrate the potential for hydroconversion to deconstruct EVA multilayer films into valuable products in a reasonable amount of time. Future work will investigate EVA biopharmaceutical films, which contain additional polyolefin barrier layers, to evaluate the capability of hydroconversion to deconstruct more complex films.