Catalytic pyrolysis of plastic waste using metal-incorporated activated carbons for monomer recovery and carbon nanotube synthesis

Martínez-Narro, Gerardo; Phan, Ha H.; Hassan, Samaila; Beaumont, Simon K.; Phan, Anh N.

Abstract

As the global plastic waste crisis intensifies, innovative and sustainable solutions are urgently needed. This study evaluated waste-derived metal-incorporated activated carbon (AC) catalysts for the pyrolysis of mixed plastic waste to generate value-added products, focusing on product yield distribution, composition, hydrogen, and carbon nanotube (CNT) formation. Pyrolysis-catalysis experiments were conducted using a two-stage fixed-bed reactor, wherein the temperature was maintained at 500 °C in first stage (pyrolysis) and varied (500, 600, and 700 °C) in the second stage (catalysis). The tested ACs were incorporated with nickel (Ni-AC), iron (Fe-AC), and zinc (Zn-AC) to assess the impact of metal particles distributed on the carbonaceous support in the second stage. The results from the ACs were compared to those obtained using zeolite (H-ZSM-5), Raw-AC, and non-catalytic runs. The Ni-AC and Fe-AC demonstrated superior catalytic activity, with Ni-AC being more efficient in producing hydrogen (4.24wt%) and CNTs (34.5wt%) with diameters of approximately 30nm, and Fe-AC leading to higher gas yields (68.8wt%) and CNTs (12.4wt%) of around 60nm. In contrast, Zn-AC and Raw-AC presented limited effectiveness, although Raw-AC moderately outperformed Zn-AC with enhanced gas yields and reduced oil/wax yields. The zeolite H-ZSM-5 exhibited the highest gas yields (78wt%), converting heavy fractions into lighter molecules, notably the monomers ethylene and propylene. These findings provide valuable insights into catalyst selection and optimization for plastic waste pyrolysis processes, with H-ZSM-5 being the most effective catalyst for monomer recovery, and Ni-AC and Fe-AC demonstrating promising results.

Citation

Martínez-Narro, G., Phan, H. H., Hassan, S., Beaumont, S. K., & Phan, A. N. (2024). Catalytic pyrolysis of plastic waste using metal-incorporated activated carbons for monomer recovery and carbon nanotube synthesis. Journal of Environmental Chemical Engineering, 12(2), Article 112226. https://doi.org/10.1016/j.jece.2024.112226

• Journal Article Type: Article
• Acceptance Date: Feb 15, 2024
• Online Publication Date: Feb 16, 2024
• Publication Date: 2024-04
• Deposit Date: Feb 23, 2024
• Publicly Available Date: Feb 23, 2024
• Journal: Journal of Environmental Chemical Engineering
• Print ISSN: 2213-3437
• Electronic ISSN: 2213-3437
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 12
• Issue: 2
• Article Number: 112226
• DOI: https://doi.org/10.1016/j.jece.2024.112226
• Public URL: https://durham-repository.worktribe.com/output/2273270