Sustainable catalytic upcycling of medical face mask wastes into hydrocarbon-rich gases for potential carbonaceous nanomaterial production

Abstract

The increased public health awareness in the post corona virus disease 2019 era and the usage of healthcare and cleanroom facilities have contributed to the escalation of the global face mask waste disposal. This study investigates the catalytic pyrolysis of face mask waste into hydrocarbon-rich gases, which holds significant value as prospective carbonaceous nanomaterial (CNM) precursors. The pyrolysis condition was fixed at 500 °C with a heating rate of 20 °C/min. The catalyst, Ni/ZSM-5 was produced from different metal impregnation strategies with various metal precursors namely nickel (Ni), magnesium (Mg), and calcium (Ca). Unlike conventional pyrolysis which focuses on liquid yield, the innovative multi-zone pyrolysis reactor with Ni/ZSM-5 produced an impressive gas yield of 47.0% (mass fraction), of which 79.1% was hydrocarbon gas that could be useful for promising CNM production. The crystallinity of Ni/ZSM-5 and the composition of gas product were largely maintained even after regeneration. Individual and mixed polymer kinetics studies were done using the model-free Ozawa–Flynn–Wall (OFW) method to obtained the activation energy, which was reduced by 9.4% when the Ni/ZSM-5 catalyst was introduced. These results indicate that the viability of Ni/ZSM-5 in reducing the reaction activation energy while concurrently improving the gas yield and quality for potential CNM production. This study improves the optimization of catalytic pyrolysis processes for producing high-quality non-condensable hydrocarbon gas, particularly in sustainable material synthesis.

Graphical abstract