Engineering synergistic Mg/C Co-doped sites on ZIF-67-derived cobalt catalysts for enhanced peroxymonosulfate activation toward tetracycline removal

Co-Mg 1.5 @C were successfully prepared to activate PMS for TC degradation. • The degradation mechanism is the synergistic effect of free radicals (SO 4 . •– , •OH, O 2 •– ) and non-free radicals ( 1 O 2 ). • A small amount of Mg doping can greatly reduce the leaching of cobalt ions. • In a continuous flow reactor, the catalyst achieved complete degradation of both TC and MB within 300 min, with the treated effluent exhibiting substantially reduced toxicity. Aquatic antibiotic pollution caused by tetracycline (TC) has posed a severe threat to ecological security and human health, and the development of efficient and stable cobalt-based catalysts for peroxymonosulfate (PMS) activation is the key to solving this problem via advanced oxidation processes. However, the existing cobalt-based catalysts suffer from the defects of active site agglomeration, serious cobalt leaching and poor stability. In this work, a facile synthesis of Mg/C co-doped Co-based catalyst (Co-Mg@C) derived from ZIF-67 for enhanced activation of PMS toward TC degradation. The introduction of Mg not only modulates the electronic structure of Co active sites but also effectively suppresses Co agglomeration. Meanwhile, the carbon matrix derived from fumaric acid (FA) provides a conductive and porous framework, which improves both electron transfer kinetics and the overall dispersibility of the catalyst. The optimized Co-Mg 1.5 @C catalyst exhibited exceptional catalytic activity, achieving nearly complete TC removal within 60 min, while maintaining robust performance over a wide pH range and in the presence of various co-existing ions. Radical quenching and electron paramagnetic resonance (EPR) studies confirmed that TC degradation proceeded via the synergistic action of both radical (SO 4 •– , •OH and O 2 •– ) and non-radical ( 1 O 2 ) species. The Co-Mg 1.5 @C catalyst also displayed excellent reusability with minimal cobalt leaching and broad-spectrum activity towards multiple organic pollutants. Application tests in real water matrices and toxicity assessments further confirmed its environmental compatibility and practical feasibility. This study provides valuable insights into the rational design of cost-effective and stable MOFs-derived catalysts for advanced water treatment applications. Download: Download high-res image (468KB) Download: Download full-size image