Versatile pathways for oxidating organics via peroxymonosulfate activation by different single atom catalysts confining with Fe–N4 or Cu–N4 sites

Herein, we prepared two kinds of single-atom catalysts (SACs) with uniformed coordination structures (M−N4, M = Fe, and Cu) for evaluating the versatile pathways of peroxymonosulfate (PMS) activation by different metal sites. Fe-SAC exhibited a higher catalytic performance than that of Cu-SAC for chloroquine phosphate (CQP) oxidation. Results showed that the high-valent iron-oxo species accounted for 74.5 % for CQP oxidation in Fe-SAC/PMS system, while radicals (SO4•– and HO•) dominated the CQP oxidation (58.3 %) in Cu-SAC/PMS system, which was associated to the different spin-state of the metal sites for PMS adsorption and breakage of OO in PMS as well as the intermediates in versatile pathways. The SACs were then fixed onto the catalytic filter for PMS activation, which showed stable and effective catalytic performance for versatile recalcitrant organics. Overall, this work not only provided the atomic-level knowledge on PMS activation, but also gave the potential applications of Fenton-like for water remediation.