An Evaluation of the Performance and Economics of Membranes and Separators in Single Chamber Microbial Fuel Cells Treating Domestic Wastewater

Abstract

The cost of materials is one of the biggest barriers for wastewater driven microbial fuel cells (MFCs). Many studies use expensive materials with idealistic wastes. Realistically the choice of an ion selective membrane or nonspecific separators must be made in the context of the cost and performance of materials available. Fourteen membranes and separators were characterized for durability, oxygen diffusion and ionic resistance to enable informed membrane selection for reactor tests. Subsequently MFCs were operated in a cost efficient reactor design using Nafion, ethylene tetrafluoroethylene (ETFE) or polyvinylidene fluoride (PVDF) membranes, a nonspecific separator (Rhinohide), and a no-membrane design with a carbon-paper internal gas diffusion cathode. Peak power densities during polarisation, from MFCs using no-membrane, Nafion and ETFE, reached 67, 61 and 59 mWm-2, and coulombic efficiencies of 68±11%, 71±12% and 92±6%, respectively. Under 1000Ω, Nafion and ETFE achieved an average power density of 29 mWm-2 compared to 24 mWm-2 for the membrane-less reactors. Over a hypothetical lifetime of 10 years the generated energy (1 to 2.5 kWhm-2) would not be sufficient to offset the costs of any membrane and separator tested.

Influence of the electrode size on microbial anode performance

“…The model illustrates the drastic effect of the ionic conductivity. For instance, with an ionic conductivity of 0.2 S.m À1 , as encountered when wastewaters are used as the electrolyte [16,48], the 50-cm 2 anode would display a drastic performance loss (dashed line, Fig. 3B).…”

Process intensification technologies for CO2 capture and conversion – a review

“…This technology has been employed for carbon capture [159], in photochemical [160,161], electrochemical [162], and thermochemical [82] CO 2 conversion processes aiming to overcome mass transfer resistance and enhance energy efficiency. With multifunctional units such as these membrane-integrated reactors, combining two functions into one unit should reduce the capital cost of the single unit compared to the individual reactor and membrane separation unit [163]. However, this technology suffers from limitations which include operating under high pressure [58], high membrane cost, cathode flooding, fuel crossover, membrane degradation in electrochemical systems [141].…”

High-performance biodegradable membrane for point of need paper-based micro-scale microbial fuel cell analytical devices

“…In a typical two chamber MFC, a PEM is used to separate the anodic and cathodic compartments, to avoid crossover of different dissolved substances, including gases. PEM membranes allow a selective transport of protons from the anode to the cathode whereas avoid the homogenization of the MFC compartments and prevents the oxygen transport into the anode chamber [11]. Nafion ® is a polymeric material with high mechanical strength, chemical stability, high electrical conductivity and selective permeability that is commonly used as PEM in MFCs [12–15].…”