Waste PET-Derived Porous Carbon for Adsorption-Coupled Nonradical Fenton-Like Degradation of Organic Dyes

Waste polyethylene terephthalate (PET) was upcycled into a bifunctional porous carbon (PET-C-1) through base-catalyzed hydrolysis followed by one-step pyrolysis. The hydrolysis-derived potassium terephthalate precursor suppressed aromatic carbon loss and promoted in situ pore development, yielding PET-C-1 with a BET surface area of 1149 m² g⁻¹, a pore volume of 1.11 cm³ g⁻¹, and partially graphitized framework. The carbonization process also generated H₂- and CO-containing gas products, suggesting the possibility of additional product valorization. The PET-C-1 exhibits rapid adsorption of organic dye malachite green (MG) and acts as a metal-free catalyst for H₂O₂ activation and oxidative degradation of MG. Complete removal of 50 ppm MG from water was achieved within 8 min. Mechanistic studies suggest that the PET-C-1/H₂O₂ system proceeds mainly through a surface-mediated nonradical electron-transfer pathway rather than a conventional ·OH-dominated Fenton process. This work demonstrates a feasible route for converting waste PET into functional carbon catalysts and highlights the potential of plastic-derived carbons for adsorption-coupled oxidative water treatment.