Electrocatalytic oxidation of bisphenol A using optimized Fe/Cu cathodic catalysts: Biotoxicity and microbial community analysis in bioelectro-Fenton systems

Bioelectro-Fenton (BEF) systems have attracted attention for sustainable pollutant treatment, but the application of Fe/Cu-based cathodic catalysts remains limited by instability, metal leaching, and potential toxic by-products. The treatment of bisphenol A (BPA), a persistent and toxic endocrine disruptor, further challenges wastewater remediation. This study uses the response surface method to optimize the preparation conditions of Fe/Cu cathode catalysts for enhancing the performance of BEF systems by increasing H₂O₂ generation, removing BPA, and decreasing the internal resistance of the cathode. The optimized Fe/Cu bimetallic catalyst applied to the BEF system exhibits 99.76 % removal of 10 mg/L BPA in 11 h, significantly outperforming the BEF with the monometallic catalysts (73.43 % and 58.51 % for Fe and Cu, respectively). The charge transfer resistance of the Fe/Cu catalyst is reduced by 61.79 %–63.09 % compared with that of the Fe and Cu catalysts. The optimized Fe/Cu catalyst is reused up to the eighth cycle with 73.34 % BPA removal efficiency, demonstrating its reuse potential. Microbial community analysis at the anode showed a marked shift, with Pseudomonas abundance increasing from 3.46 % to 51.76 %, suggesting that the optimized Fe/Cu catalyst promoted electroactive microbial enrichment and enhanced system performance.