Biological Fenton reaction mediated by N and Fe co-doped carbon dots for ketoprofen degradation

Microbial-driven Fenton reactions are essential sources of reactive oxygen species in the aqueous environment and important pathways for pollutant degradation. However, their rates are usually limited by microbial respiration. Herein, N and Fe co-doped CDs (N, Fe-CDs) were used to construct a biological Fenton system with marine community YEP-1 for ketoprofen (KTP) removal. The addition of N, Fe-CDs significantly increased the aerobic degradation rate of KTP by 60.8 % at 48 h. Further analysis showed that N, Fe-CDs enhanced the microbial electron transfer system activity of YEP-1 to produce more H 2 O 2 . Moreover, the regeneration of Fe(II) in extracellular N, Fe-CDs was achieved under aerobic conditions, which was beneficial to activate the extracellular H 2 O 2 for more ·OH generation. Based on the metagenome analysis, N, Fe-CDs significantly increased the populations of genera Exiguobacterium , Leucobacter and Microbacterium . The enriched genes related to electron transfer and Fe(III) reduction were found to be closely associated with Microbacterium . Furthermore, the relative abundances of genes related to the chemotaxis and degradation of aromatic compounds were also increased. These results indicated that biological enzyme-catalyzed processes and N, Fe-CD-mediated Fenton reaction were jointly involved in KTP degradation. This work further advances our understanding of N, Fe-CDs-mediated microbial Fenton reactions.