Salinity Effect on the Microbial Fuel Cell Performance

The objective of this study was to investigate the effects of salinity on power generation and microbial community structure in the microbial fuel cell (MFC). Three two-chamber MFCs (MFC-A, MFC-B, MFC-C) were used to conduct experiments. The MFC-A was operated sequentially using solutions of 0, 20, 40, 60, and 70 g/L NaCl in the anode chamber of the cell. The MFC-B was operated with solutions of 0 and 40 g/L NaCl and the MFC-C with solutions of 0 and 70 g/L NaCl. Results showed that the salinity inhibited power generation in all the MFCs. In the MFC-A, the maximum voltage outputs and CEs decreased from 660 to 130 mV and from 67% to 4%, respectively, with the NaCl concentrations from 0 to 70 g/L. However, the NaCl concentrations did not affect the removal efficiency of substrate (glucose) in the MFC, which reached 100% at the end of every cycle. Moreover, voltages could be recovered to the maximum value (630 mV) within 60 h after replacing the salt solutions with water. With the solutions of 40 and 70 g/L NaCl in the MFC-B and MFC-C, respectively, no obvious electricity was generated after two cycle operations.