Capacitive bio-anodes for electricity production in Microbial Fuel Cells

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Adaptation and adoption of green technologies is necessary to create a sustainable future. The Microbial Fuel Cell (MFC) is such a new technology which gained large momentum the last decade for renewable electricity production. The technology is based on electrochemically active microorganism which converts organic waste streams into electricity. At the same time, clean water is produced.

State of the art technology is the fluidized bed capacitive MFC (Figure 1). It consists of an anodic charging column and discharging cell separated by a membrane. The bacteria grow on the fluidized activated carbon granules while converting organic compounds of the wastewater into electrons, protons and carbon dioxide. Charge is stored as electron inside the granule. Electro-neutrality is obtained by a proton double layer close to the outer side of the granule. Electrons and protons are released in the discharging cell while contacting the current collector. Electricity can be generated via an external circuit to the cathode while the protons pass the membrane to react with oxygen and the previously referenced electrons to produce clean water.