Performance of Microbial Reverse-Electrodialysis Cells for Power Generation at Different External Resistance

Abstract

In this study, the effect of external resistance on the microbial reverse-electrodialysis cell (MRC) performance using organic-rich wastewater as an electron donor was examined. The optimum of external resistance was determined to be 300 Ω. In such condition, the power density of 1.53 ± 0.198 W/m 2 , substrate removal of 52 ± 2.3%, Coulombic efficiency of 70 ± 2.6%, energy recovery of 3.0 ± 0.4%, and energy efficiency of 53 ± 7.1% were obtained in the MRC. The differences in power density at different external resistances were mainly due to the changes in internal resistance and ion flux efficiency in the MRC. The external resistance affected substrate removal and Coulombic efficiency through the length of batch cycle time, and current density exchanged as well as the Tafel slope. Furthermore, the proper external resistance applied to the reactor created high power production; thus, high energy efficiency and energy recovery were achieved. These results demonstrated that selecting proper external resistance was an essential key for a successful MRC operational.