A trash-to-treasure approach of deriving Cu-doped carbonaceous catalysts from disposable masks motivating peroxymonosulfate decomposition and organics high-efficiency mineralization

The past global pandemic of COVID-19 made people be accustomed to wear disposable face masks to defend against epidemic disease, posing significant challenges in proper disposal of numerous plastic wastes. Herein, a simple immersion and calcination approach was proposed to convert polypropylene-based masks into Cu-doped carbonaceous catalysts (Cu x -DMC) for efficient peroxymonosulfate (PMS) activation and wastewater purification. After immersion in a 0.02 M CuSO 4 solution, the resulting Cu 0.02 -DMC exhibited a larger surface area and highly abundant reactive sites than the undoped sample, indicating excellent catalytic performance. Upon the addition of 1 mM PMS, 100 mL 10 mg/L of seven representative organics were almost completely degraded within 30 min. The resulting mineralization efficiencies ranged from 41 % to 65 %. Additionally, rapid purification of both actual lake water and municipal secondary effluent was obtained. Such high efficiency was attributed to 1 O 2 , O 2 ·- , ·OH and SO 4 ·- produced in PMS activation process, during which the formed [Cu(Ⅱ)OOSO 3 - ] metastable intermediate on Cu 0.02 -DMC surface and the redox cycles between different Cu chemical states played crucial roles. Owing to the high efficiency in PMS activation, anti-interference ability for complex water matrices, and high stability for reuse, Cu x -DMC derived from “trash-to-treasure” approach exhibited potential applications in wastewater treatment.