Copper single-atom catalysts for broad-spectrum antibiotic-resistant bacteria (ARBs) antimicrobial: Activation of peroxides and mechanism of ARBs inactivation.

Antibiotic-resistant bacteria (ARBs) have been widely detected in wastewater and become a potential threat to human health. This work found that low-load single-atom copper (0.1 wt%) anchored on g-C ₃ N ₄ (SA-Cu/g-C ₃ N ₄ ) exhibited excellent ability to activate H ₂ O ₂ and inactivate ARBs during the photo-Fenton process. The presence of SA-Cu/g-C ₃ N ₄ (0.4 mg/mL) and H ₂ O ₂ (0.1 mM) effectively inactivated ARBs. More than 99.9999 % (6-log) of methicillin-resistant Staphylococcus aureus (MRSA), and carbapenem-resistant Acinetobacter baumannii (CRAB) could be inactivated within 5 min. Extended-spectrum β-lactamase-producing pathogenic Escherichia coli (ESBL-E) and vancomycin-resistant Enterococcus faecium (VRE) were killed within 10 and 30 min, respectively. In addition, more than 5-log of these ARBs were killed within 60 min in real wastewater. Furthermore, D ₂ O-labeling with Raman spectroscopy revealed that SA-Cu/g-C ₃ N ₄ completely suppressed the viable but nonculturable (VBNC) state and reactivation of bacteria. Electron paramagnetic resonance spectroscopy results demonstrated that g-C ₃ N ₄ mainly produced ¹ O ₂ , while SA-Cu/g-C ₃ N ₄ simultaneously produced both ¹ O ₂ and •OH. The •OH and ¹ O ₂ cause lipid peroxidation damage to the cell membrane, resulting in the death of the bacteria. These findings highlight that the SA-Cu/g-C ₃ N ₄ catalyst is a promising photo-Fenton catalyst for the inactivation of ARBs in wastewater.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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