Improved decolorization of dye wastewater and enhanced power output in the electrically stacked microbial fuel cells with H₂O₂ modified corncob anodes

Abstract

Abstract The key operational constraints of the microbial fuel cell (MFC) technology in achieving its due potential are the high cost of electrodes and the difficulties in scaling up. To address these issues, carbonized corncob anodes were prepared and modified with the hydrogen peroxide (H 2 O 2 ) to increase the oxygenated functional groups favoring the extracellular electron transfer between the microbes and electrodes. Compared to the MFC with anode without any modification, that is, bare anode, the single chambered MFC with 20% H 2 O 2 modified anode exhibited excellent electro‐catalytic activity and a 91% decrease in the internal resistance (decreased from 35 ± 0.5 to 3.0 ± 0.6 kΩ) along with 89% increase in the maximum power density (increased from 8.8 ± 0.7 to 89.7 ± 0.6 mW/m 2 ). MFCs with 20% H 2 O 2 modified anode resulted in high decolorization efficiency of real dye wastewater (RDW) up to 92% which is 18% higher than that of the MFC with the bare anode. In order to boost the power output, the system was designed and studied by electrically stacking the 24 individual units of the MFC with the modified anode into parallel and series configurations. In parallel stacking and series stacking, the power output was 18.9 and 13.5 times higher than the single MFC unit, respectively. The RDW degradation rate was in the order of parallel stack > series stack > single MFC unit.

Key findings

• ▸MFC with 20% H2O2 modified anode exhibited excellent electro-catalytic activity.
• ▸Internal resistance decreased from 35 ± 0.5 to 3.0 ± 0.6 kΩ.
• ▸Maximum power density increased from 8.8 ± 0.7 to 89.7 ± 0.6 mW/m².

Keywords

Identifiers

DOI

10.1002/ep.13638

Journal

Environmental Progress & Sustainable Energy

Year

2021