Catalytic application of polyvinyl chloride in thermochemical conversion of biomass

Biorefineries are sustainable alternatives to petrochemical-based industrial systems. However, their practical implementation has been constrained by the environmental and economic challenges associated with their reliance on harsh homogeneous catalysts. This study explored the utilization of wasted polyvinyl chloride (PVC) as a potential catalyst in a corncob biorefinery. Thermogravimetric analysis of the PVC and corncob mixture samples revealed thermal degradation profiles distinct from the predicted outcomes, indicating modified reaction pathways. Co-pyrolysis also enhanced H₂ generation by 120 % compared to corncob pyrolysis owing to the reaction between PVC-derived HCl and corncob derivatives. Gas monitoring experiments demonstrated that HCl generated from PVC played a critical role in catalyzing biomass conversion into valuable chemicals such as furfural, levoglucosenone, and 5-hydroxymethylfurfural at temperatures <360 °C. Especially, co-pyrolysis of PVC and corncob at a 1:1 blending ratio increased furfural yield by approximately 1,700 % compared to corncob pyrolysis. Furthermore, CO₂-assisted pyrolysis reduced polyaromatic hydrocarbon formation while enhancing the generation of monoaromatic hydrocarbon and syngas. These findings demonstrate the potential of PVC and CO₂ in corncob pyrolysis to enhance overall biorefinery efficiency and mitigate pollutant generation, offering a promising pathway for sustainable biorefinery development.