Upcycling of end-of-life wind turbine blades: Phosphoric acid-activated balsa carbon as a catalyst for the co-pyrolysis of epoxy resin and polyvinyl chloride core into phenolic compounds.

To enhance the resource utilization of end-of-life wind turbine blades (EolWTBs), this study proposes an innovative catalytic co-pyrolysis approach integrating catalyst preparation and synergistic recycling of different blade components. Specifically, this study first utilized H3PO4 as an activator to convert balsa wood from the balsa wood-filled part (EolWTB-1) into an H3PO4-AC catalyst, which was subsequently utilized to catalyze the co-pyrolysis of the glass fiber-reinforced polymer (EolWTB-3) and PVC-filled (EolWTB-4) parts. This strategy realized both waste-derived catalyst production and high-value chemical recovery in a single system. The 2H3PO4-1AC catalyst exhibited superior activity at 600 °C, yielding 61.30 % phenol and 87.81 % total phenolic compounds. Co-pyrolysis at a 0.5:0.5 mass ratio of EolWTB-3/EolWTB-4 achieved enhanced selectivity (65.23 % phenol, 94.65 % total phenolics), surpassing theoretical values and demonstrating strong synergistic effects. Kinetic analysis revealed a significant reduction in activation energy, confirming catalytic efficiency and reaction facilitation. Mechanistic insights indicated that the phosphorus-enriched surface and abundant active sites accelerated aromatization reactions and phenolic formation. This work introduces a sustainable and integrated recycling pathway that transforms composite waste into high-value products, offering a novel strategy for circular utilization of wind turbine blades.