Enhanced Activation of Peroxymonosulfate for Tetracycline Degradation by Modifying N‐doped Biochar With Magnetite Particles: Performance and Active Site Determination

ABSTRACT Peroxymonosulfate (PMS)‐mediated advanced oxidation processes have attracted increasing attention for the degradation of antibiotics in wastewater due to their high degradation efficiency and relatively low cost. However, the design of efficient catalysts for PMS activation remains a major challenge. In this work, an N‐doped Fe 3 O 4 /CC900 catalyst was prepared via a hydrothermal method to activate PMS for tetracycline degradation. The degradation efficiency in the Fe 3 O 4 /CC900/PMS system reached 96.1% within 60 min, and the reaction rate constant reached 0.125 min −1 , which was about 1.19 times higher than that of the CC900/PMS system and 1.52 times higher than that of the Fe 3 O 4 /PMS system. Quenching experiments demonstrated that SO 4 • − , •OH, and 1 O 2 were the dominant reactive species during the reaction. Further studies revealed that the enhanced catalytic performance could be attributed to the synergistic activation between Fe 3 O 4 nanoparticles and CC900, which increased the number of reactive sites and the specific surface area, and pyridinic N, abundant surface hydroxyl groups, and the redox cycle of iron played critical roles in PMS activation. This study highlights the key role of N in improving the PMS activation, and provides a new insight for the rational design of environmentally friendly and efficient catalysts for wastewater treatment.