Hydrogen peroxide production in a pilot-scale microbial electrolysis cell

A pilot-scale dual-chamber microbial electrolysis cell (MEC) equipped with a carbon gas-diffusion cathode was evaluated for H(2)O(2) production using acetate medium as the electron donor. To assess the effect of cathodic pH on H(2)O(2) yield, the MEC was tested with an anion exchange membrane (AEM) and a cation exchange membrane (CEM), respectively. The maximum current density reached 0.94–0.96 A/m(2) in the MEC at applied voltage of 0.35–1.9 V, regardless of membranes. The highest H(2)O(2) conversion efficiency was only 7.2 ± 0.09% for the CEM-MEC. This low conversion would be due to further H(2)O(2) reduction to H(2)O on the cathode or H(2)O(2) decomposition in bulk liquid. This low H(2)O(2) conversion indicates that large-scale MECs are not ideal for production of concentrated H(2)O(2) but could be useful for a sustainable in-situ oxidation process in wastewater treatment.