Bio-electrochemical characterization of air-cathode microbial fuel cells with microporous polyethylene/silica membrane as separator

• Volumetric power densities ranging from 30 to 90 W·m− 3 of RVC foam
• Biofouling on both membranes with 150–300 μM thickness after 8 months of operation
• A total of 77 bacterial 16S rRNA gene sequences recovered on both MFC membranes
• Shannon diversity index of 1.330 for PE membrane and 2.032 for Nafion®

The aim of this work was to study the behavior over time of a separator made of a low-cost and non-selective microporous polyethylene membrane (RhinoHide®) in an air-cathode microbial fuel cell with a reticulated vitreous carbon foam bioanode. Performances of the microporous polyethylene membrane (RhinoHide®) were compared with Nafion®-117 as a cationic exchange membrane. A non-parametric test (Mann–Whitney) done on the different sets of coulombic or energy efficiency data showed no significant difference between the two types of tested membrane (p < 0.05). Volumetric power densities were ranging from 30 to 90 W·m− 3 of RVC foam for both membranes. Similar amounts of biomass were observed on both sides of the polyethylene membrane illustrating bacterial permeability of this type of separator. A monospecific denitrifying population on cathodic side of RhinoHide® membrane has been identified. Electrochemical impedance spectroscopy (EIS) was used at OCV conditions to characterize electrochemical behavior of MFCs by equivalent electrical circuit fitted on both Nyquist and Bode plots. Resistances and pseudo-capacitances from EIS analyses do not differ in such a way that the nature of the membrane could be considered as responsible.