Upcycling waste cartons into an efficient Fenton-like chainmail catalyst CoOx@C: Process, performance, and mechanism

Waste cartons produced by e-commerce and the express delivery industry pose urgent environmental and social challenges, making their recycling a critical issue in recent years. In this study, a novel strategy for upcycling waste cartons into a Fenton-like chainmail catalyst, CoO x @C-P-8 (CoO x confined carbonaceous matrix), through a one-step pyrolysis process using waste cartons adsorbed cobalt nitrate was proposed. The catalytic activity of CoO x @C-P-8 in activating peroxymonosulfate (PMS) for the removal of tetracycline hydrochloride (TCH) was thoroughly evaluated. The results indicated that the combination CoO x @C-P-8 (0.3 g/L) and PMS (1.0 mM) could remove 92 % of TCH within 60 min. Mechanistic studies revealed that both singlet oxygen ( 1 O 2 ) and radicals (i.e. SO 4 •− , O 2 •− and HO • ) contributed to TCH removal, with cobalt-loading, N-doping, and the defective graphitic structure identified as the key governing factors. The unique chainmail structure of CoO x @C-P-8 endowed it with pronounced resistance to interference from ions (Cl − , NO 3 − , HCO 3 − , H 2 PO 4 − , K + , Mg 2+ , and Na + ) and pH variations (pH 3.0–11.0). Furthermore, the high environmental viability of CoO x @C-P-8, evidenced by ease of magnetic separation and simple catalyst regeneration, was demonstrated. This work may offer a feasible strategy for upcycling waste cartons and also contribute substantively to the advancement of wastewater decontamination.