The effects of different electron donors and electron acceptors on perchlorate reduction and bioelectricity generation in a microbial fuel cell

The effects of different electron donors and electron acceptors on the performance of microbial fuel cell (MFC) were investigated. In the ClO4− system, the optimum electron donor and initial perchlorate (ClO4−) concentration were acetate and 150 mg/L, respectively. In the ClO4−−NO3− and ClO4−−ClO3− systems, the perchlorate reduction rates were retarded and the lag time was increased with increasing concentrations of nitrate and chlorate; the output voltage increased when nitrate was reduced, and the output voltage decreased when chlorate was reduced. In the ClO4−−SO42− systems, the perchlorate reduction rates and output voltages did not dramatically decrease until the sulfate (SO42−) concentration increased to 600 mg/L. Thermodynamic and electrochemical analyses were used to explain the difference in the reduction orders of multiple electron acceptors and responses of the anode activity. The microbial analysis showed that the electron acceptors did not change the composition of the anodic microbial community. The dominant species were responsible for the enhancement of the higher perchlorate reduction rate and the higher output voltage.