title: Oxygen availability effect on the performance of air-breathing cathode microbial fuel cell.
abstract: The effect of the oxygen availability over the performance of an air-breathing microbial fuel cell (MFC) was studied by limiting the oxygen supply to the cathode. It was found that anodic reaction was the limiting stage in the performance of the MFC while oxygen was fully available at cathode. As the cathode was depleted of oxygen, the current density becomes limited by oxygen transport to the electrode surface. The exerted current density was maintained when oxygen mole fraction was higher than 10% due to the very good performance of the cathodic catalysts. However, the current density drastically falls when working at lower concentrations because of mass transfer limitations. In this sense it must be highlighted that the maximum exerted power, when oxygen mole fraction was higher than 10%, was almost three times higher than that obtained when oxygen mole fraction was 5%. Regarding to the wastewater treatment, a significant decrease in the COD removal was obtained when the MFC performance was reduced due to the limited availability of oxygen, which indicates the significant role of the electrogenic microorganisms in the COD removal in MFC. In addition, the low availability of oxygen at the cathode leads to a lower presence of oxygen at the anode, resulting in an increase in the coulombic efficiency.
authors.affiliation: Dept. of Chemical Engineering, University of Castilla-La Mancha, ITQUIMA, Avenida Camilo José Cela S/N., 13071, Ciudad Real, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Mateo
authors.affiliation: Faculty of Chemical Sciences & Technologies, Chemical Engineering Dept., University of Castilla-La Mancha, Edificio Enrique Costa Novella, Avenida Camilo José Cela S/N., 13071, Ciudad Real, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodrigo
authors.affiliation: IBB-Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, 1049-001, Lisbon, Portugal.
authors.forename: Luis Pina
authors.initials: LP
authors.lastname: Fonseca
authors.affiliation: Chemical Engineering Dept., University of Castilla-La Mancha, Edificio Enrique Costa Novella, Avenida Camilo José Cela S/N., 13071, Ciudad Real, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Cañizares
authors.affiliation: Faculty of Chemical Sciences & Technologies, Chemical Engineering Dept., University of Castilla-La Mancha, ITQUIMA, Avenida Camilo José Cela S/N., 13071, Ciudad Real, Spain.|IBB-Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, 1049-001, Lisbon, Portugal.
authors.forename: Francisco Jesus
authors.initials: FJ
authors.lastname: Fernandez-Morales
mesh_terms: D001674:Bioelectric Energy Sources; D004553:Electric Conductivity; D004566:Electrodes; D004867:Equipment Design; D006863:Hydrogen-Ion Concentration; D008962:Models, Theoretical; D010100:Oxygen / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism
chemical_list: D010100:Oxygen
keywords: cathode; mass transport; microbial fuel cell; oxygen availability