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 HO production using acetate medium as the electron donor. To assess the effect of cathodic pH on HO 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 in the MEC at applied voltage of 0.35-1.9 V, regardless of membranes. The highest HO conversion efficiency was only 7.2 ± 0.09% for the CEM-MEC. This low conversion would be due to further HO reduction to HO on the cathode or HO decomposition in bulk liquid. This low HO conversion indicates that large-scale MECs are not ideal for production of concentrated HO but could be useful for a sustainable in-situ oxidation process in wastewater treatment.