Low-cost separators for enhanced power production and field application of microbial fuel cells (MFCs)

New and different separators were investigated as alternatives to well-known ion exchange separators such as Nafion and Cation Exchange membrane (CMI). In polarization tests, the maximum power densities of new separators without functional groups were comparatively higher than those of Nafion and CMI. The non-woven fabric Polypropylene (PP80) exhibited maximum voltage of 0.477 V (with 1000 Omega), which was similar to that of Nafion (0.481 V), and resulted in the highest power density of 121 mW/m(2) (Nafion; 118 mW/m(2)). Polypropylene 80 and 100 exhibited relatively smaller ohmic resistances of 11 Omega and 2 Omega, respectively, compared to others with resistances ranging from 13 to 41 Omega. Concerning oxygen diffusion, all types of size selective separators exhibited high oxygen mass transfer compared to Nafion and CMI. This high oxygen diffusion was likely the reason for the lower columbic efficiencies (CE) of PP80 (44%) and PP100 (42%) compared to Nafion (50%). PP80 exhibited a high proton mass transfer coefficient (K-H = 11 x 10(-5)cm/s) compared to all ion exchange and size selective separators included in this study. These results suggest that low-cost separators could be used for field applications of MFCs for higher cell voltage while minimizing oxygen diffusion. (C) 2014 Elsevier Ltd. All rights reserved.