Electro-Catalytic Electrodes and Ionic Exchange Membranes in Microbial Fuel Cell
Résumé
Microbial Fuel Cell (MFC), an emerging energy device that produces sustainable bio-energy and treats wastewater and industrial effluent. The MFC consists of two compartments separated by an ionic exchange membrane. In the anolyte, the electro-catalytic biofilm formed on the anode, degrades the organic matter into electrons and proton. Whilst in the catholyte, the cathode reduces dissolved oxygen. The carbon based material usually used at the anode because it is biocompatible and chemically stable in the electrolyte. In order to increase its active surface, its modification with conducting polymer can increase the current density produced from MFC. Besides, the materials based on carbon and graphite are widely used as cathodes, but they should be enriched with noble metals necessary for the catalysis of the electrochemical reaction. In MFC, the polymer ionic membrane can affect significantly its performance. In effect, various parameters such as membrane internal resistance, pH splitting, oxygen diffusion, and substrate loss and bio-fouling, have been investigated. In addition, the slow transfer of proton at neutral pH, creates pH gradient at electrodes. Thus, the accumulation of protons at the anode causes acidification slowing oxidation activity. Conversely, the weak proton availability near cathode reduces the rate of cathode reaction. The use of proton membrane can replaced by an anionic membrane. The adjustment of pH in anolyte and cathode compartments, influence the cell voltage. The highest value was obtained with anionic membrane.