Enhancing the power generation in microbial fuel cells with effective utilization of goethite recovered from mining mud as anodic catalyst

• Recovery of goethite from mine mud was confirmed from material characterization.
• Recovered goethite from iron ore mine shows catalytic behavior for anodic reactions.
• MFC with treated goethite coated anode gave fivefold power compared to control MFC.
• Improved capacitance observed in MFC with treated goethite (hematite) coated anode.
• Goethite catalyst accelerates the electron transfer between anode and microbes.

Catalytic effect of goethite recovered from iron-ore mining mud was studied in microbial fuel cells (MFCs). Characterization of material recovered from mining mud confirms the recovery of iron oxide as goethite. Heat treated goethite (550 °C) and untreated raw goethite were coated on stainless-steel anode of MFC-1 and MFC-2, respectively; whereas, unmodified stainless-steel anode was used in MFC-3 (control). Fivefold increment in power was obtained in MFC-1 (17.1 W/m3 at 20 Ω) than MFC-3 (3.5 W/m3). MFC with raw goethite coated anode also showed enhanced power (11 W/m3). Higher Coulombic efficiency (34%) was achieved in MFC-1 than control MFC-3 (13%). Decrease in mass-transport losses and higher redox current during electrochemical analyses support improved electron transfer with the use of goethite on anode. Cheaper goethite coating kinetically accelerates the electron transfer between bacteria and anode, proving to be a novel approach for enhancing the electricity generation along with organic matter removal in MFC.

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