Microbial Fuel Cells (MFCs) are bio-electrochemical transducers that generate electricity as a direct result of microbial metabolism, when breaking down organic matter for continuous growth and maintenance. On the other hand, Microbial Electrolysis Cells (MECs) consume electricity to drive chemical reactions and recover hydrogen or other high value chemicals, at the cathode half-cell . In MFCs, electric current is generated when for every electron donated to the electrode surface, a proton is transferred from the anode to the cathode. Other cations such as Na+ or K+ may be present in significantly higher concentrations and are more likely to be transferred through a cation exchange membrane . This normally results in electro-osmotically dragged water from the anode to the cathode, and often results in a phenomenon known as cathode flooding, which is a problem for MFCs and other chemical fuel cells.
To this day, bio-electrosynthesis has not been reported for energy-generating MFCs, since it is associated with energy-consuming MECs. The main aim of this work was therefore to investigate the effects on MFC performance of low-cost catalyst-free electrode materials, in conjunction with cation and water transport to the cathode half-cell, in the context of beneficial water accumulation and recovery of valuable resources.