Iron Oxide-Modified Anode for Enhanced Sunset Yellow FCF Azo Dye Decolorization in Microbial Fuel Cell and Phytotoxicity Assessment

Microbial fuel cell (MFC) technology is emerging as an effective tool for bioelectricity generation and wastewater treatment. This work is aimed at investigating the impact of an Fe2O3-modified carbon felt (CF) anode in a dual-chamber MFC for the treatment of synthetic wastewater containing sunset yellow FCF dye (at different concentrations). The Fe2O3 nanoparticles were synthesized using a hydrothermal approach, characterized, and then used to modify CF as an MFC anode. The MFC experiments were performed using bare and Fe2O3-modified CF anodes to investigate their efficiency in decolorizing sunset yellow FCF dye while simultaneously generating bioelectricity. Furthermore, the phytotoxicity of synthetic wastewater containing the sunset yellow FCF dye on wheat plants (Triticum aestivum) was investigated before and after treatment in MFCs. MFCs 1, 3, and 5 were equipped with bare CF anodes and fed with synthetic wastewater containing sunset yellow FCF dye at 250 mg/L, 200 mg/L, and 150 mg/L, respectively. Whereas MFC-2, -4 and -6 were equipped with Fe2O3-modified CF anodes and fed with sunset yellow FCF dye at concentrations of 250 mg/L, 200 mg/L, and 150 mg/L, respectively. MFC-2, -4 and -6 demonstrated superior MFC operational characteristics regarding dye decolorization with simultaneous power generation. The power densities for MFC-2, -4 and -6 were calculated to be 303.03 mW/m2, 353.45 mW/m2, and 402.15 mW/m2, with dye decolorization efficiencies of 76 ± 3.0%, 80 ± 4.2%, and 93.3 ± 3.0%, respectively. Moreover, phytotoxicity studies revealed that the treated wastewater samples exhibited lower phytotoxicity than the untreated samples. Conclusively, MFCs fabricated with Fe2O3-modified CF displayed better operational performance characteristics compared to those equipped with an unmodified CF anode.