Mariam Khalil

University of Jordan / Zeolite Catalysis

Advisor: Prof. Fawzi Banat

Mariam Khalil engineers hierarchical ZSM-5 zeolite catalysts with a secondary mesopore network introduced by controlled alkaline desilication, targeting the catalytic cracking of pyrolysis oils derived from mixed post-consumer plastic waste into a propylene- and ethylene-enriched light naphtha cut at the University of Jordan's Chemical Engineering department. The plastic pyrolysis oil problem is significant: simple pyrolysis produces a heavy, contaminated oil unsuitable for direct use, but catalytic upgrading over conventional microporous zeolites suffers from severe pore blockage by bulky polyaromatic coke precursors. Mariam's hierarchical ZSM-5 — characterised by BET surface areas of 380 m²/g (micropore) plus 140 m²/g (mesopore) — retains the Brønsted acid site density needed for cracking selectivity while allowing the heavy molecules to access the active sites before coke deposition deactivates the catalyst. Her microreactor experiments at 550 °C with a polypropylene pyrolysis oil feed show that propylene + ethylene yield increases from 22% over conventional ZSM-5 to 41% over her hierarchical catalyst at equal space velocity, with catalyst lifetime extended 3.4-fold before regeneration is required. Collaboration with the Jordan Petroleum Refinery Company provides industrial feed samples and downstream product valorisation analysis, while a SESAME synchrotron user project enables operando XAS catalyst characterisation.