Enhanced dye treatment and bioelectricity generation in microbial fuel cells: the role of magnetite-inoculated anode and cosubstrates.

This study investigated the influence of cosubstrate complexity and magnetite-inoculated anodes on microbial fuel cells (MFCs) treating synthetic dyeing wastewater (500 mgCOD/L, 50 mg/L Reactive Black 5). Two MFCs types were constructed: one with magnetite pre-inoculated anodes (MFCM) and another with sludge-only inoculated anodes (MFCS). Both MFCs were operated with either starch or ethanol as the cosubstrate, and in both cases, MFCM consistently outperformed MFCS. For instance, with starch, MFCM achieved 99 % decolorization and a peak voltage of 380.74  mV within 30 hours, compared to 89 % and negligible, unstable voltage in MFCS. A 1500  Ω resistance was optimal for decolorization and electricity generation in MFCM. Microbial analysis revealed that magnetite pre-inoculation enriched electroactive genera, enhanced diversity and extracellular electron transfer, and stabilized microbial networks across cosubstrates. These findings highlight the potential of magnetite pre-inoculated anodes as a novel practical strategy for early anode biofilm control, with significant implications for scalable MFCs applications.