Single cobalt atoms anchored on Ti 3 C 2 T x with dual reaction sites for efficient adsorption–degradation of antibiotic resistance genes

The assimilation of antibiotic resistance genes (ARGs) by pathogenic bacteria poses a severe threat to public health. Here, we reported a dual-reaction-site-modified Co_SA/Ti₃C₂T_x (single cobalt atoms immobilized on Ti₃C₂T_x MXene) for effectively deactivating extracellular ARGs via peroxymonosulfate (PMS) activation. The enhanced removal of ARGs was attributed to the synergistic effect of adsorption (Ti sites) and degradation (Co-O₃ sites). The Ti sites on Co_SA/Ti₃C₂T_x nanosheets bound with PO₄^3- on the phosphate skeletons of ARGs via Ti-O-P coordination interactions, achieving excellent adsorption capacity (10.21 × 10¹⁰ copies mg^-1) for tetA, and the Co-O₃ sites activated PMS into surface-bond hydroxyl radicals (•OH_surface), which can quickly attack the backbones and bases of the adsorbed ARGs, resulting in the efficient in situ degradation of ARGs into inactive small molecular organics and NO₃. This dual-reaction-site Fenton-like system exhibited ultrahigh extracellular ARG degradation rate (k > 0.9 min^-1) and showed the potential for practical wastewater treatment in a membrane filtration process, which provided insights for extracellular ARG removal via catalysts design.