Tailoring Microbial Electrochemical Cells for Production of Hydrogen Peroxide at High Concentrations and Efficiencies

A microbial peroxide producing cell (MPPC) for H2O2 production at the cathode was systematically optimized with minimal energy input. First, the stability of H2O2 was evaluated using different catholytes, membranes, and catalyst materials. On the basis of these results, a flat-plate MPPC fed continuously using 200 mm NaCl catholyte at a 4 h hydraulic retention time was designed and operated, producing H2O2 for 18 days. H2O2 concentration of 3.1 gL(-1) H2O2 with 1.1 Whg(-1) H2O2 power input was achieved in the MPPC. The high H2O2 concentration was a result of the optimum materials selected. The small energy input was largely the result of the 0.5 cm distance between the anode and cathode, which reduced ionic transport losses. However, >50% of operational overpotentials were due to the 4.5-5 pH unit difference between the anode and cathode chambers. The results demonstrate that a MPPC can continuously produce H2O2 at high concentration by selecting compatible materials and appropriate operating conditions.