More effective peroxymonosulfate activation for tetracycline removal from Co-FeN/@BC assisted by micro--electrolysis: Performance and mechanism

Preparation of N-doped bimetallic (Co/Fe) MOFs and their loading on biochar (Co-FeN/@BC). Micro-electrolytic co-catalyst activated PMS for the efficient degradation of tetracycline (TC). The mechanism was comprehensively investigated by EPR analysis, free radical quenching experiments and electrochemical measurements. The results showed that micro-electrolysis prompted the catalyst to synergize with peroxymonosulfate (PMS) activation to degrade TC, and the pathways of TC degradation included free radical, non-free radical and high-valent metal pathways. Microelectrolysis accelerates electron transfer, Fe/Co activates PMS to become a high-valent metal after electron transfer, and PMS is activated to produce 1O2 and SO·- 4. The main active substances for TC degradation by PMS activation were 1O2, SO·- 4, FeIVO2+ and CoIVO2+. The active substances attacked the TC molecules to form intermediates, which were eventually mineralized into CO2 and H2O.