Hydrocracking of surgical face masks over Y zeolites: catalyst development, process design and life cycle assessment

Muhammad Usman Azam, Auguste Fernandes, Ines Graca* (Corresponding Author), Waheed Afzal* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
3 Downloads (Pure)


This study highlights the hydrocracking route for the management of surgical face masks, made of polypropylene, into liquid fuels. Hydrocracking experiments were performed at 325 ℃ and 10 bar cold H2 pressure over Ni-loaded HY and steamed HY zeolites. Ni-loaded steamed Y zeolite demonstrated to be the best catalyst leading to considerably high conversion (100 %) and selectivity to liquids (85.5 wt%). The increase in the external surface area and mesoporous volume that improved the bulk polymer molecules diffusion, combined with the uniformly dispersed Ni particles and the additionally generated Lewis acidity, were at the origin of the observed behaviour. This catalyst also showed reasonable stability and ability to be thermally regenerated. From the environmental perspective, life cycle assessment shows the benefits of hydrocracking over pyrolysis and incineration. Therefore, our results demonstrate that Ni-loaded steamed Y zeolites could be promising catalysts for the upcycling of surgical face masks to gasoline range fuels, with minimum environmental impacts.
Original languageEnglish
Article number128704
Number of pages17
Early online date22 May 2023
Publication statusPublished - 1 Oct 2023

Bibliographical note

This study was funded by The LEVERHULME TRUST (Grant DS-2017-073). Muhammad Usman Azam, a Leverhulme Trust Doctoral Scholar, is part of the 15 PhD scholarships of the “Leverhulme Centre for Doctoral Training in Sustainable Production of Chemicals and Materials” at the University of Aberdeen (Scotland, United Kingdom). Auguste Fernandes thanks Portuguese FCT for funding (CQE - UIDB/00100/2020 and UIDP/00100/2020; IMS-LA/P/0056/2020; contract hiring under DL57/2016 law).


  • Surgical face masks
  • hydrocracking
  • hierarchical steamed zeolites
  • Process simulation
  • life cycle assessment


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