Study on in situ degradation of antibiotics by bio-electro-fenton driven by electrogenic ecological floating beds and its mechanism

The electrogenic ecological floating bed (EFB), which integrated a traditional ecological floating bed with a microbial electrochemical system (E-EFB), held significant promise for water remediation. However, its efficacy was often constrained by low electron transfer efficiency between microorganisms and electrodes. To overcome this constraint, this study developed an innovative bio-electro-Fenton enhanced E-EFB system employing γ-FeOOH- or CeO₂-modified carbon felt cathodes. The electrochemical properties and catalytic performance of these modified cathodes were systematically evaluated through electrochemical measurements and pollutant degradation experiments. Results indicated that the modified cathodes significantly enhanced electrochemical activity and reduced internal resistance. Before adding SMX in the influent, compared to the conventional E-EFB, the E-EFB/Fe system achieved increases of approximately 12.87 % in COD removal, 15.03 % in TOC removal, and 14.12 % in TP removal. The E-EFB/Ce system also showed improvements, with 6.20 % higher COD, 16.47 % higher TOC, and 1.88 % higher TP removal. After the addition of SMX to the influent, the removal rates decreased in all samples; however, the removal efficiencies of EFB/Fe and E-EFB/Ce remained higher than that of E-EFB. Notably, the E-EFB/Fe configuration achieved a superior SMX removal rate of 45.78 %. Furthermore, power generation performance improved, with output voltage increasing by 23.3–29.24 %. Microbial diversity analysis revealed that the incorporation of γ-FeOOH and CeO₂ catalysts considerably enhanced microbial richness and diversity within the E-EFB. Overall, this study supports the practical application of bio-electro-Fenton systems with different modified cathodes for effective in situ degradation of SMX in wastewater. • Constructed the bio-electro-Fenton system basing on E-EFB. • The SMX removal rates of E-EFB/Fe and E-EFB/Ce were 45.8 % and 43.9 %. • E-EFB/Fe had the better power generation performance.