A recyclable and self-supporting spinel anode for electrochemical activation of peroxymonosulfate to sulfamethoxazole degradation

The unavoidable release of persistent antibiotics such as sulfamethoxazole (SMX) poses severe threats to ecosystems and human health. Electro-activated peroxymonosulfate (PMS) represents a promising advanced oxidation process (AOP) for antibiotic removal, but faces challenges due to the high cost, poor stability, and low efficiency of the anode. Herein, an efficient, reusable, economical, and self-supporting LiFeO 2 film encapsulated Fe (Fe@LiFeO 2 ) anode is developed via molten salt anodization. Under the optimized conditions (50 mM SMX, 2 mM PMS, and 10 mA/cm 2 ), the Fe@LiFeO 2 anode facilitates the removal of 97% SMX within 60 min with the assistance of PMS, significantly outperforming the counterparts of only PMS or electro-oxidation systems. The enhanced degradation performance is attributed to the synergistic effect between Fe@LiFeO 2 , current and PMS. It is revealed that the activated PMS (PMS*), direct electron transfer (DET), and oxygen-evolution reactions take place during the degradation process, and the radical species (•OH/SO 4 • - /O 2 • - ) and non-radical ( 1 O 2 /PMS*/DET) together contribute to SMX degradation. Moreover, the electrode maintains high degradation efficiency during continuous tests and can be simply regenerated to the original level even after failure. Besides, owing to the low cost of materials and synthetic routes, the anode shows good economic advantages. This work provides a highly promising anode for the AOPs in the wastewater treatment area.