Degradation of cathode performance over time is one of the major drawbacks in applications of microbial fuel cells (MFCs) for wastewater treatment. Over a two month period the resistance of air cathodes (RCt) with a polyvinylidene fluoride (PVDF) diffusion layer increased of 111% from 70 ± 10 mΩ m2 to 148 ± 32 mΩ m2. Soaking the cathodes in hydrochloric acid (100 mM HCl) restored cathode performance to RCt = 74 ± 17 mΩ m2. Steam, ethanol, or sodium hydroxide treatment produced only a small change in performance, and slightly increased RCt. With a polytetrafluoroethylene (PTFE) diffusion layer on the cathodes, RCt increased from 54 ± 14 mΩ m2 to 342 ± 142 mΩ m2 after two months of operation. The acid concentration was critical for effectiveness in cleaning, as HCl (100 mM) decreased RCt to 28 ± 8 mΩ m2. A lower concentration of HCl (<1 mM) showed no improvement, and vinegar (5% acetic acid) produced 48 ± 4 mΩ m2.
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Renewable Energy, Sustainability and the Environment
- Waste Management and Disposal