Humic Acid and Iron Chelation Modified Anode Improves the Electrochemical Performance of Marine Sediment Microbial Fuel Cell

Marine sediment microbial fuel cell (MSMFCs) can be utilized as a long lasting power source to drive small instruments to work for long time on ocean floor and its higher power has a significant meaning for practical application. Anode modification can greatly improve the performance of MSMFCs. Herein, humic acid (HA) and humic acid-iron ion complex (HA-Fe) were used to modify the anode for constructing a better MSMFCs. The results indicated that HA-Fe modified anode, better than HA modification, significantly improved the MSMFCs cell power output. The maximum power density of HA-Fe modified MSMFCs is 165.3mWm −2 , which are 6.5-folds of blank MSMFCs. The number of microorganisms on anode, redox activity, and relative kinetic activity were 1.8-, 6.1-, and 13.1-folds of blank MSMFCs, respectively. The MSMFCs improvement would be attributed to the electron transfer media of HA and the valence conversion of Fe ions. A synergistic interaction between the naturally occurring HA and Fe ions on the anodic surface in marine sediments would make the modified anodes have ‘renewable’ characteristics, which is beneficial for the MSMFCs to maintain its long-term higher power.