Thermo-catalytic decomposition of polystyrene waste: Comparative analysis using different kinetic models

Area of Science:

• Polymer Chemistry
• Materials Science
• Chemical Engineering

Background:

• Increasing polymer production leads to substantial municipal solid waste challenges.
• Limited landfill space necessitates effective waste polymer recycling techniques.
• Waste polystyrene presents a significant component of municipal solid waste.

Purpose of the Study:

• To investigate the catalytic effect of synthesized copper oxide on waste polystyrene pyrolysis.
• To determine the kinetic and thermodynamic parameters of the pyrolysis reaction.
• To assess the suitability of copper oxide as a catalyst for lower-temperature polymer decomposition.

Main Methods:

• Pyrolysis of waste polystyrene using a thermogravimetric analyzer under an inert nitrogen atmosphere.
• Experimentation at various heating rates: 5°Cmin⁻¹, 10°Cmin⁻¹, 15°Cmin⁻¹, and 20°Cmin⁻¹.
• Analysis of thermogravimetric data using model-fitting (Coats-Redfern) and model-free (Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose, Friedman) methods.

Main Results:

• Copper oxide demonstrated a catalytic effect, reducing the activation energy for polystyrene degradation.
• Activation energy values ranged from 99.41 to 149.15 kJmol⁻¹ across different models.
• The lowest activation energy observed suggests efficient decomposition at lower temperatures in the presence of the catalyst.

Conclusions:

• Synthesized copper oxide is a suitable catalyst for the decomposition of waste polystyrene.
• The catalytic activity facilitates pyrolysis at reduced temperatures, enhancing recycling efficiency.
• The determined kinetic and thermodynamic parameters are valuable for understanding solid waste reaction mechanisms in practical applications.