Effect of cathode electron acceptors on simultaneous anaerobic sulfide and nitrate removal in microbial fuel cell

Abstract

The current investigation reports the effect of cathode electron acceptors on simultaneous sulfide and nitrate removal in two-chamber microbial fuel cells (MFCs). Potassium permanganate and potassium ferricyanide were common cathode electron acceptors and evaluated for substrate removal and electricity generation. The abiotic MFCs produced electricity through spontaneous electrochemical oxidation of sulfide. In comparison with abiotic MFC, the biotic MFC showed better ability for simultaneous nitrate and sulfide removal along with electricity generation. Keeping external resistance of 1,000 Ω, both MFCs showed good capacities for substrate removal where nitrogen and sulfate were the main end products. The steady voltage with potassium permanganate electrodes was nearly twice that of with potassium ferricyanide. Cyclic voltammetry curves confirmed that the potassium permanganate had higher catalytic activity than potassium ferricyanide. The potassium permanganate may be a suitable choice as cathode electron acceptor for enhanced electricity generation during simultaneous treatment of sulfide and nitrate in MFCs.