Effect of electrode types on simultaneous anaerobic sulfide and nitrate removal in microbial fuel cell

• Effect of electrodes on simultaneous sulfide and nitrate removal was studied in MFC.
• The MFCs with graphite felt or rod as electrodes were shown to remove substrate.
• Higher steady current densities of MFCs with graphite felt as electrodes were obtained.
• Better catalytic activity of graphite felt was displayed by CV curves.

The effect of electrode types on simultaneous sulfide and nitrate removal were studied in two-chamber microbial fuel cells (MFCs). Graphite rod and graphite felt as electrodes were compared and evaluated in terms of substrate removal and electricity generation. When the influent sulfide concentration elevating from 60 mg L−1 to 780 mg L−1 gradually, the MFCs both showed good capacities to remove substrate, no matter what material used as electrodes. Nitrogen and sulfate were the main end products. The steady current densities of the MFC with graphite felt as electrodes were nearly twice as large as that with graphite rod. It could be explained by the linear relationship between the electrons released by substrates and the accepted by electrodes. The CV curves also showed that the graphite felt has a higher catalytic activity than the graphite rod. The graphite felt was more suitable as electrodes for the MFCs treating sulfide and nitrate simultaneously.