Impact of the presence of common polymer additives in thermal and catalytic polyethylene decomposition

Chemical recycling of waste plastics has attracted growing global interest in recent years. However, the role that polymer additives play during these depolymerization reactions is still unknown. In this work, we investigate the impact of typical additives on the rate of reaction of pyrolysis and catalytic decomposition over zeolites. Further, we regenerate the spent catalysts after contact with additive-containing polymer and assess modifications to the catalyst structure and activity. All the tested additives were found to hinder the activity of ZSM-5 catalysts. We also unveil that some additives (amines, phenols) can be fully removed from the catalyst via calcination, whereas others (phosphites, metallic stearate) may permanently deposit and modify sites. The deposition of such impurities on zeolites may change their alkane cracking capabilities. After regeneration, zinc deposited on the catalyst (resulting from plastic degradation reactions) was able to increase hexane cracking conversion by over 7-fold when compared to fresh ZSM-5.

» Author: Ana Carolina Jerdy, Tram Pham, Miguel ?ngel Gonz?lez-Borja, Pascale Atallah, David Soules, Ron Abbott, Lance Lobban, Steven Crossley

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