Upcycling of end-of-life wind turbine blades: Enhanced phenolic compounds production through catalytic co-pyrolysis of epoxy resin and polyvinylchloride with zinc chloride-balsa activated carbon

Pyrolysis of core materials (balsa wood, polyethylene terephthalate and polyvinylchloride) mixed directly with end-of-life wind turbine blades (EolWTBs) increased by-products and reduced the product quality. To maximize EolWTBs utilization, this study innovatively synthesized zinc chloride–activated carbon (ZnCl 2 –AC) using balsa cores (EolWTB-1) as waste-to-value for catalytic co-pyrolysis of epoxy resins (EolWTB-3) and polyvinylchloride cores (EolWTB-4) to enhance the phenolic compounds production. Fixed-bed experiments showed that 1ZnCl 2 –1AC with ZnCl 2 activator and a Zn/balsa ratio of 1:1 exhibited the optimal performance at 600 °C. A synergistic effect was further observed when EolWTB-3 and EolWTB-4 were co-pyrolyzed at a mixing ratio of 0.75:0.25 with selectivity of 76.27 % and 96.27 % for phenol and phenolic compounds, respectively. The reusability test showed that the decreasing trend of phenol selectivity was slow and much higher than that of the non-catalytic group. Reaction mechanism studies showed that the high specific surface area of the catalyst with abundant Lewis acid sites promoted the aromatization of macromolecular organic compounds and the conversion of oxygen-containing functional groups to phenolic hydroxyl groups. The findings will simultaneously enable the waste-to-value conversion of balsa wood and upgrade the reuse value of EolWTBs, offering an alternative method for recycling EolWTBs. • Synthesis of ZnCl 2 –AC catalyst realised waste-to-value of balsa wood cores in EolWTB. • Catalytic pyrolysis at 600 °C is most favourable for competitive reaction of phenols. • ZnCl 2 –AC had the highest phenol yield at ZnCl 2 activation with a Zn/balsa ratio of 1:1. • A synergistic effect was observed during the co-pyrolysis EolWTB-3 with EolWTB-4. • The reusability of 1ZnCl 2 -1AC for the catalytic production of phenol was verified.