Sustainable processes for the conversion of waste plastics into value chemicals

   School of Engineering

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  Dr W Afzal, Dr Ines Graca  Applications accepted all year round  Self-Funded PhD Students Only

About the Project

Plastics are commodity materials of utmost importance since they constitute the group of materials with one of the highest world consumptions. However, 95% of these plastics worth USD 80-120 billion annually are only utilized for a single-use and treated as waste after that 1. A large share of waste plastics is inadequately managed (i.e., mismanaged) and is at a high risk of leakage to the natural environment and oceans via waterways, winds, and tides which cause deaths and injuries of countless marine species 2. Conventional and linear end-of-life waste management options i.e., landfill, and incineration are unable to address this problem in a sustainable way. Similarly, current chemical recycling approaches including gasification and pyrolysis lead to certain industrial problems e.g., the high capital cost to design a high-temperature resistant reactor for gasification and formation of large molecules due to the recombination of olefins during pyrolysis operation 3. Therefore, catalytic hydrocracking of waste plastics may tackle the aforementioned issues as this process has been recognized as a promising way to convert waste plastics into saturated liquid products and other value-added chemicals. Zeolites have been extensively utilized as a source of catalyst. However, microporosity and diffusion limitations significantly reduced their application. Similarly, present modification techniques to enhance the porosity may be responsible to compromise the crystallinity, acidity, and stability of the parent structure. Therefore, this project aims to fabricate bi-functional zeolitic coupled metal and other solid acid catalysts to produce on-demand good quality liquid fuels and value-added chemicals by cracking waste plastics at mild conditions. The key previous publications 4,5 and studies 6 somehow reported the importance and suitability of process; however, they often lack the suitability, stability, and recyclability of the catalyst. The project may have a combination of objectives such as catalysts synthesis, their characterization using various analytical methods to study the physio-chemical properties, and experimental tests under optimized reaction conditions to study the synergistic effect of heterogeneous catalysts with exceptional performance for the hydrocracking of plastics. Moreover, it also includes to study the reaction kinetics, perform kinetic modelling, process simulations and based on this knowledge, conduct tecno-economic and life cycle analysis.

Selection will be made on the basis of academic merit. The successful candidate should have, or expect to obtain, a UK Honours degree at 2.1 or above (or equivalent) in Engineering or applied or industrial chemistry and preferably have an appetite for laboratory work, reaction engineering, catalysis, reaction kinetic modelling, process simulation, life cycle and techno-economic analysis. 


Formal applications can be completed online:

• Apply for Degree of Doctor of Philosophy in Engineering

• State name of the lead supervisor as the Name of Proposed Supervisor

• State ‘Self-funded’ as Intended Source of Funding

• State the exact project title on the application form

When applying please ensure all required documents are attached:

• All degree certificates and transcripts (Undergraduate AND Postgraduate MSc-officially translated into English where necessary)

• Detailed CV, Personal Statement/Motivation Letter and Intended source of funding

Informal inquiries can be made to Dr W Afzal ([Email Address Removed]) with a copy of your curriculum vitae and cover letter. All general enquiries should be directed to the Postgraduate Research School ([Email Address Removed])

Funding Notes

This PhD project has no funding attached and is therefore available to students (UK/International) who are able to seek their own funding or sponsorship. Supervisors will not be able to respond to requests to source funding. Details of the cost of study can be found by visiting


1. Dogu, O. et al., (2021). The chemistry of chemical recycling of solid plastic waste via pyrolysis and gasification: State-of-the-art, challenges, and future directions. Progress in Energy and Combustion Science, 84, p.100901.
2. Plastic Pollution - Our World in Data.
3. Costa, C. S. et al., (2021). H-USY and H-ZSM-5 zeolites as catalysts for HDPE conversion under a hydrogen reductive atmosphere. Sustainable Energy & Fuels, 5(4), pp.1134-1147.
4. Munir, D. et al., (2017). Hydrocracking of a plastic mixture over various micro-mesoporous composite zeolites. Powder Technology, 316, 542-550.
5. Uekert, T. et al., (2021). Solar-driven reforming of solid waste for a sustainable future. Nature Sustainability, 4(5), pp.383-391.
6. Liu, S. et al., (2021). Plastic waste to fuels by hydrocracking at mild conditions. Science Advances, 7(17), eabf8283.
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