Enhanced performance of microbial fuel cells with enriched ferrous iron oxidation microflora at room temperatures

Adding ferric ions (Fe3+) in catholyte can enhance performance of microbial fuel cells (MFCs). This work adopted biocathode with enriched Fe2+ oxidizing microflora to perform in situ Fe2+ oxidization so the MFC could operate with prolonged period with increased cell open circuit voltage (1037 mV) and maximum power density (71.8 Wm(-3) at 154 Am-3) but with minimal needs for iron replenishment. The Fe2+-oxidizing microflora was very effective so the Fe3+/Fe2+ could reach high ratio, which was composed of Acidithiobacillus (73.8%), Acidiphilium (12.1%), Mycobacterium (6.92%), Sulfobacillus (2.66%), Ochrobactrum (1.30%), Alicyclobacillus (0.82%), and other minor species. The membrane transport and cell replication were shown to be their most important metabolic activities. The formation of jarosite and hydronium jarosite by Fe3+ and sulfate led to loss of iron ions, which should be minimized in operation.

Automated summary

The addition of ferric ions in the catholyte can enhance the performance of microbial fuel cells, by utilizing Fe2+ oxidizing microflora in the biocathode. This results in prolonged operation with increased cell open circuit voltage and maximum power density, while minimizing the need for iron replenishment.