Oğuzhan Akin, Qing He, Mohammadhossein Havaei, Fatma Defne Calik, Daniël Withoeck, Robin John Varghese, Parviz Yazdani, Paul Van Steenberge, Kevin M. Van Geem
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引用次数: 0
Abstract
The coexistence of polyethylene terephthalate (PET) and polyolefins in plastic waste poses a significant challenge for pyrolysis-based recycling, as PET decomposition generates oxygenates that reduce product quality. To address this, we developed a two-stage reactor system that catalytically upgrades vapors from PET–LDPE mixtures using Ga- and Zn-impregnated HZSM-5 catalysts. XPS analysis revealed that impregnation with Ga and Zn leads to the formation of GaOx and ZnOH+ species, which introduce new Lewis acid sites. When these sites are located near Brønsted acid sites, synergistic interactions enhance both deoxygenation and aromatization, improving the catalytic performance of HZSM-5. At 600 °C, PET pyrolysis produces significant amounts of CO2, CO, and benzoic acid, resulting in oxygen-rich pyrolysis oil. While unmodified HZSM-5 achieves full deoxygenation, the resulting PyOil yield is modest, ranging from 24 to 34 wt%. In contrast, Ga- and Zn-modified catalysts increase PyOil yield to ∼50 wt% and improve mono-aromatic (BTX) selectivity to 80–89 % by shifting the acid site distribution toward weaker acidity, thereby favoring decarboxylation, decarbonylation, and aromatization. Notably, Zn-HZSM-5 maintained high BTX selectivity even with increasing PET content, outperforming Ga-HZSM-5, which exhibited higher polyaromatic hydrocarbon formation under similar conditions. These results demonstrate the potential of Ga- and Zn-modified HZSM-5 catalysts for the efficient conversion of mixed plastic waste into BTX-rich oils suitable for fuel and chemical applications.
期刊介绍:
Catalysis Today focuses on the rapid publication of original invited papers devoted to currently important topics in catalysis and related subjects. The journal only publishes special issues (Proposing a Catalysis Today Special Issue), each of which is supervised by Guest Editors who recruit individual papers and oversee the peer review process. Catalysis Today offers researchers in the field of catalysis in-depth overviews of topical issues.
Both fundamental and applied aspects of catalysis are covered. Subjects such as catalysis of immobilized organometallic and biocatalytic systems are welcome. Subjects related to catalysis such as experimental techniques, adsorption, process technology, synthesis, in situ characterization, computational, theoretical modeling, imaging and others are included if there is a clear relationship to catalysis.