Enhanced Performance of Bioelectrochemical Systems Using Natural Source Materials for Methyl Orange Wastewater Treatment
To enhance the electricity generation and decolorization efficiency of bioelectrochemical systems (BES) for azo dye wastewater, this study introduced pomelo peel biochar as anode material and flavonoid-rich Chinese herbal medicines as electron mediators (EMs) into microbial fuel cells (MFCs). The anodes were prepared by chemical activation with KOH, ZnCl2, and H3BO3, followed by polypyrrole (PPy) modification. Among the modified anodes, PPy-PPCH3BO3-CC exhibited the best electrochemical performance. The EMs were derived from aqueous extracts of Scutellaria baicalensis (Huangqin), Ginkgo biloba leaves, and Pueraria lobata (Gegen). The extract from Scutellaria baicalensis showed the highest electron transfer capability. In the MFC system equipped with the optimal anode and Scutellaria baicalensis extract, the maximum output voltage reached (587±10) mV, power density increased to 423.12 mW·m−2, Coulombic efficiency was (57.85±1.06)%, COD removal efficiency was (77.45±0.92)%, charge transfer resistance (Rct) decreased to 7.15 Ω, and methyl orange decolorization rate reached (95.86±1.12)%. These results were significantly superior to the control group, demonstrating that natural source materials can effectively enhance the performance of BES for methyl orange wastewater treatment.