Microbial Fuel Cells (MFCs) represent a promising technology for renewable energy production; their most likely short-term applications being a method of simultaneous wastewater treatment and electricity production. However, at this moment, the most challenging problem MFCs faced by is the low power densities using the existing design. These devises which are capable of converting waste to electricity basically rely on the use of platinum (Pt) as a catalyst in the electrode and a proton exchange membrane (PEM) between the cathode and anode. In most studies so far Nafion~R has been the membrane of choice. However, use of Pt as a catalyst is not feasible at all due to the high cost and future (un)availability and thus there is an urgent need for some low cost sustainable alternatives. Also, the use of Nafion~R might not be feasible owing to its high cost and its permeability to oxygen. We have tried to reduce these severe limitations by using our in-house developed non platinized Teflon coated carbon electrode as air cathode and novel permeable membranes in a dual chamber MFC with acetate as the sole carbon source. The proposed ion permeable membrane, Zirfon~R was tested for its oxygen mass transfer coefficient, K0 which was then compared with Nafion~R. The K0 for Zirfon~R was calculated as 1.92 × 10~(-3) cms-1. Further, when this membrane was used in place of conventional polymer electrolyte membrane, there was no reduction in the performance of the electrodes for oxygen reduction at cathode and acetate oxidation at anode. The above mentioned gas porous electrodes were first tested in an electrochemical half cell configuration for their ability to reduce oxygen and later in a full MFC set up. It was observed that these non platinized air electrodes perform very well in the presence of acetate under MFC conditions (pH 7, room temperature) for oxygen reduction. Current densities of -0.43 mAcm~(-2) for non-platinized graphite electrode and -0.6 mAcm~(-2) for non-platinized activated charcoal electrode at -200 mV vs. Ag/AgCl of applied potential were obtained. Another innovation which is being explored currently is integrating this membrane directly onto the electrode surface thereby reducing the spacing between the electrodes substantially and then using this sandwich type configuration in the MFC. The oxygen diffusion coefficient of this integrated Zirfon~R coated assembly was of similar magnitude as that of single membrane alone. It can be expected that use of these sustainable low cost air cathodes and ion permeable membranes will overcome several of the current limitations in the development of real MFCs, besides the development of an efficient reactor design.
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