Enhanced Performance of a Microbial Fuel Cell with a Capacitive Bioanode and Removal of Cr (VI) Using the Intermittent Operation.

This study investigated a system which simultaneously produced electricity and stored energy in the MFC integrated MnO2-modified capacitive bioanode. Compared to the noncapacitive anode, the maximum power density of MFC with MnO2-modified bioanode reached 16.47 W m-3, which was 3.5 times higher than that of the bare anode (4.71 W m-3). During the charging-discharging experiment, the MFC with a capacitance bioanode has a higher average peak current density of 5.06 mA cm-2 and 36 times larger than that with the bare bioanode. With the capacitive electrode, it is possible to let the MFC at the same time for production and storage of renewable electricity. Then two different operations (intermittent operation and continuous operation) of the MFC with a capacitive bioanode were studied to degrade Cr (VI) in cathode chamber. Results showed that the Cr (VI) removal rates of intermittent operation are much higher than that of continuous operation under the same time in the closed circuit state. This is due to the good ability of storing and releasing electron of the biological capacitor with MnO2 modified material. And this study showed that MFC with a capacitive bioanode is better adapted to treat heavy metal pollutants by intermittent mode.