Multiparameter optimization of microbial fuel cell outputs using linear sweep voltammetry and microfluidics

Abstract

A microbial fuel cell with a mature pure-culture Geobacter sulfurreducens electroactive biofilm was used for performance optimization by making rapid changes to experimental parameters in microchannels while monitoring their effect using linear sweep voltammetry. A systematic investigation of polarization behavior and evaluation of system resistivity provided important figures of merit and mechanistic insights on the effects of flow rates, concentrations, and temperature. After individual parameters were optimized, a synergistic effect was observed by applying optimal parameters together, resulting in improved current and maximum power densities, compared to stable values at unoptimized conditions. Continued acclimation for just 2 days under these conditions resulted in further improvements to anode area-normalized current and power maxima (10.49 ± 0.23 A m−2 and 2.48 ± 0.27 W m−2), which are among the highest reported in the literature for a microfluidic MFC. In keeping with other accepted normalization protocol using the area separating anode and cathode chambers, the output densities were 64 A m−2 and 15 W m−2, which are near the theoretical maximum outputs achievable with an MFC system.