Shift to continuous operation of an air-cathode microbial fuel cell long-running in fed-batch mode boosts power generation

ABSTRACT

Microbial fuel cells (MFCs) which are operated in continuous mode are more suitable for practical applications than fed batch ones. The aim of the present study was to characterize an air-cathode MFC operating in continuous mode and to determine the intrinsic properties for suitable performance and scalability. Air-cathode MFCs were constructed from plexiglass with a total working volume of 220 mL. Zirfon® separator used in this MFC had cross section area of 100 cm². The air cathode MFCs were operated in fed-batch mode and then shifted to the continuous mode. To determine the behavior of anode and cathode in long term operation (274 days), their contribution in MFC performance was evaluated over time. Once the active biofilm was formed, power production and substrate consumption rate were significantly higher. The internal resistance increased with the passage of time. After stabilization of biofilm when the MFC was placed in close circuit by connecting an external resistance, the anode-reference and cathode-reference electrode behavior showed that anode potential is near to the bacterial cell inside potential. The maximum open circuit voltage achieved was 623 mV and the highest power and volumetric power density were 38.03 mW/m² and 1296 mW/m³, respectively.

KEYWORDS:

• Microbial fuel cell
• internal resistance
• bioelectricity
• biofilm formation
• continuous mode
• power generation

Additional information

Funding

This research was supported by a grant from the Environmental and Energy Technology Innovation Platform (MIP2), under the project “Sewage Plus: second life of sewage as a matrix for dilution of organic waste streams.” Surajbhan Sevda gratefully acknowledges a scholarship from the Flemish Government, Department of Higher Education and Scientific Research (Vlaamse Gemeenschap) under the framework of Indo-Belgium fellowship (Academic year 2011–2012).