Effect of calcium oxide catalyst in the pyrolysis of polyethene

Abstract

Plastic pollution has become a critical environmental challenge, with polyethylene (PE) constituting nearly 30% of global plastic waste. Conventional plastic waste management methods, such as landfilling and incineration, pose significant ecological and health risks. Mechanical recycling and pyrolysis remains to be environmentally friendly methods, but mechanical recycling limited by material degradation, making pyrolysis one of the few sustainable methods for plastic waste management. This study investigates the effect of calcium oxide (CaO) as an alternative catalyst for converting waste PE into fuel through pyrolysis. Experiments compared non-catalytic and CaO-catalyzed (50%wt.) pyrolysis in a batch reactor at 300–500°C, evaluating fuel yield, kinematic viscosity, and density. Results demonstrated that CaO increased fuel yield by 20.19%, from 47.45%(non-catalyzed) to 68.36%(catalyzed).CaO also improved the quality of the fuel, that is to say, kinematic viscosity decreased from 2.815 to 2.427 mm²/s respectively , and density reduced from 0.824 to 0.806 g/cm³ respectively. These findings highlight CaO’s potential as a cost-effective, eco-friendly catalyst for plastic waste pyrolysis, particularly in developing regions like Uganda, where over 90% of plastic waste is mismanaged. The study addresses sustainable waste to energy solutions, offering a practical pathway to mitigate plastic pollution while contributing to circular economy objectives.