Goethite supplemented natural clay ceramic as an alternative proton exchange membrane and its application in microbial fuel cell

Microbial fuel cell (MFC) is a bioelectrochemical system, which treats wastewater with simultaneous recovery of bioelectricity. Costly proton exchange membrane, like Nafion-117, brings a serious bottleneck towards the sustainable scaled-up application of this technology. For an appropriate field-scale demonstration of MFC, the fabrication cost needs to be reduced drastically. This can be achieved by using low-cost proton exchange membrane (PEM) in MFCs, which would demonstrate equivalent performance as commercially available expensive PEMs. Such a novel PEM constituting 5% goethite and natural clay as a base material was synthesized, named as G-5, and it was used in MFC as a separator. This G-5 membrane was estimated to be five folds cheaper than the commercially available Nafion-117 membrane, which is popularly used in MFC. Membrane properties, like water and acetate uptake, and proton conductivity of the G-5 membrane, were evaluated and compared with Nafion-117. A power density obtained from the MFC using G-5 as PEM (112.81 ± 8.74 mW/m2) was slightly higher than the MFC with Nafion-117 as PEM (106.95 ± 5.52 mW/m2). Chemical oxygen demand removal and Coulombic efficiency for MFC with G-5 membrane were found to be 22% and 8.6% higher, respectively, in comparison with that of the MFC with Nafion-117 as PEM. Thus, low-cost G-5 membrane demonstrated the potential to be used for scaling-up of MFCs to reduce fabrication cost for successful field-scale implementation of MFCs.