Influence of polyvinyl chloride contaminant on chemical recycling of polyethylene via thermal and catalytic pyrolysis

Abstract Polyethylene (PE) is the most abundant component of plastic waste. Its chemical recycling primarily relies on pyrolysis, which produces pyrolysis oils that can be catalytically upgraded into light olefins. In practice, PE is often recycled alongside polyvinyl chloride (PVC) contaminants, which are difficult to completely separate given their use in multilayer materials. Upon heating, PVC readily releases acidic hydrogen chloride, which can negatively impact chemical recycling. However, most studies have focused on the chemical recycling of pure PE, with limited attention to the effects of PVC contamination. Here, by employing a pyrolyzer–gas chromatography–mass spectrometry/ flame ionization detector/thermal conductivity detector system, we reveal that PVC contamination significantly increases char formation at the expense of pyrolysis oils—the precursors for monomer recovery. Furthermore, rapid deactivation of the ZSM‐5 catalyst is observed, attributed to acidity loss caused by framework aluminum leaching. These deleterious effects are effectively mitigated through an ionic liquid–based dehydrochlorination pretreatment of feedstock, the kinetic model of which is developed.