College - Author 1
College of Engineering
Department - Author 1
Materials Engineering Department
Degree Name - Author 1
BS in Materials Engineering
College - Author 2
College of Engineering
Department - Author 2
Materials Engineering Department
Degree - Author 2
BS in Materials Engineering
College - Author 3
College of Engineering
Department - Author 3
Materials Engineering Department
Degree - Author 3
BS in Materials Engineering
Date
6-2025
Primary Advisor
Trevor Harding, College of Engineering, Materials Engineering Department
Additional Advisors
Shanju Zhang, College of Science and Mathematics, Chemistry & Biochemistry Department
Abstract/Summary
The growing accumulation of plastic waste, specifically polyethylene terephthalate (PET), has driven the need for more efficient and scalable chemical recycling methods. This study investigated the methanolysis of PET using zinc oxide (ZnO) nanoparticles as a catalyst and tetrabutylammonium chloride (NBu₄Cl) as an ionic liquid, aiming to reduce methanol consumption while achieving high PET conversion efficiency. ZnO nanoparticles were synthesized via wet chemistry and characterized using Dynamic Light Scattering (DLS), which showed an average particle size of 13.5 nm with a polydispersity index of 0.1556, indicating a moderately-high monodisperse distribution of particles sufficient for reactions. The main conversion product, dimethyl terephthalate (DMT), was confirmed and analyzed for purity using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Hydrogen Nuclear Magnetic Resonance (1 H NMR). PET conversion experiments showed that while a high methanol-to-PET ratio of 30:1 yielded up to 98% conversion without any catalyst, comparable efficiency was achieved using only a 10:1 ratio when 5 wt% ZnO nanoparticles were introduced, with or without the ionic liquid NBu₄Cl. At intermediate ZnO concentrations (3 wt%), the addition of NBu₄Cl improved PET conversion from 66% to 80%, indicating a potential synergistic effect under specific conditions. A cost analysis revealed that the nanoparticlecatalyzed method reduced estimated industrial-scale processing costs by 26%. These findings demonstrated the potential of ZnO nanoparticles as an effective, low-cost, and scalable catalyst for sustainable PET chemical recycling, while highlighting the need for further research into the functional contribution of the ionic liquid NBu₄Cl.
URL: https://digitalcommons.calpoly.edu/matesp/283
Included in
Catalysis and Reaction Engineering Commons, Polymer and Organic Materials Commons, Polymer Science Commons