Pre-treatment of anodic inoculum with nitroethane to improve performance of a microbial fuel cell

Abstract

Abstract Methanogenic substrate loss is reported to be a major bottleneck in microbial fuel cell (MFC), which significantly reduces the power production capacity and coulombic efficiency (CE) of this system. Nitroethane is found to be a potent inhibitor of hydrogenotrophic methanogens in rumen fermentation process. Influence of nitroethane pre-treated sewage sludge inoculum on suppressing the methanogenic activity and enhancing the electrogenesis in MFC was evaluated. MFC inoculated with nitroethane pre-treated anodic inoculum demonstrated a maximum operating voltage of 541 mV, with CE and maximum volumetric power density of 39.85% and 20.5 W/m³, respectively. Linear sweep voltammetry indicated a higher electron discharge on the anode surface due to enhancement of electrogenic activity while suppressing methanogenic activity. A 63% reduction in specific methanogenic activity was observed in anaerobic sludge pre-treated with nitroethane, emphasizing the significance of this pre-treatment for suppressing methanogenesis and its utility for enhancing electricity generation in MFC.

Key findings

• ▸Maximum operating voltage of 541 mV was achieved with nitroethane pre-treated anodic inoculum.
• ▸Coulombic efficiency (CE) and maximum volumetric power density were 39.85% and 20.5 W/m³, respectively.
• ▸Specific methanogenic activity was reduced by 63% in anaerobic sludge pre-treated with nitroethane.

Keywords

Identifiers

DOI

10.2166/wst.2018.206

Journal

Water Science and Technology

Year

2018