Sequential anode–cathode configuration improves cathodic oxygen reduction and effluent quality of microbial fuel cells

Abstract

a b s t r a c tThe reduction of oxygen at the cathode and the diffusion of protons from the anode to the cathode are currently perceived as two major bottlenecks of microbial fuel cells (MFCs). To address these issues, we have designed an MFC configuration in which the effluent of an acetate-fed anode was used as a feed for an aerated, biocatalysed cathode. The development of a cathodic biofilm achieved a four-fold increase of the current output compared with the non-catalysed graphite cathode, while the pH variation in the cathode compartment was reduced due to the additional transfer of protons via the liquid stream.The sequential anode-cathode configuration also provided for chemical oxygen demand Electron balances at the cathode revealed that the main cathodic process was oxygen reduction to water with no significant Coulombic losses. The maximal power output during polarization was 110 W/m 3 cathode liquid volume. The process could be operated in a stable way during more than 9 months of continuous operation. Excessive organic loading to the cathode should be avoided as it can reduce the long-term performance through the growth of heterotrophic bacteria.

New applications and performance of bioelectrochemical systems

“…A way to prevent this pH gradient is either to take out the membrane Liu and Logan 2004) or to pump the anolyte to the cathode to guarantee mixing (Freguia et al 2008a). Although it has been shown that both methods prevent the pH gradient to develop, it also causes substrate/product crossover giving unwanted side reactions and products.…”

Electricity Generation Coupled with Wastewater Treatment Using a Microbial Fuel Cell Composed of a Modified Cathode with a Ceramic Membrane and Cellulose Acetate Film

“…The electric voltage is proportional to the electron-driving force from anode to cathode, and the electric current is proportional to the reducing power generated by bacterial cells. The solar cells induce the electron-driving force from anode to cathode, by which the oxidation reaction coupled with bacterial catabolism may be activated in the anode and the reduction reaction of oxygen with protons and electrons may be activated in the cathode [10,39].…”

“…The combination of a Mn(IV)-modified anode and a Fe(III)-modified cathode may be ideal for composing an MFC without an electron mediator and oxidant, but not one from which catholyte aeration can be excluded [4,29,32]. In order to compose an MFC without catholyte aeration, the cathode has to function as a catalyst for the electrochemical reaction of protons, electrons, and oxygen [10], and as a redox barrier to conserve the potential difference between the anode and cathode. Graphite felt, to which neutral red (an electron mediator) is immobilized to catalyze electron transfer from bacterial cells to the electrode [30,36], generally has been used as both the anode and cathode, but it is difficult to modify membranes with this material because of its soft and weak structure.…”

A novel electrochemical process for the recovery and recycling of ferric chloride from precipitation sludge

“…The graphite granules have diameters of 1.5-6 mm and a porosity of 45%, leading to a mean nominal surface area of 1,000 cm 2 in each compartment (Freguia et al 2008). …”