Improved microbial electrolysis desalination and chemical-production cell for a high-value product: Hydrogen peroxide

Abstract

A high-value product of microbial electrolysis desalination and chemical-production cell (MEDCC) is a promising method for reducing costs and broadening the cell’s application. This study proposed a modified MEDCC in terms of hydrogen peroxide (H2O2) production, electrochemical performance, desalination, energy consumption by comparing it with conventional MEDCC. At the optimal voltage (1.0 V), the improved system achieved the H2O2 concentration of 1183 ± 32 mg/L, the energy consumption of 8.42 ± 1.39 kWh/kg H2O2, the desalination efficiency of 60.36 ± 9.24% within 12 h. Although the MEDCC-H2O2 system had a lower transfer rate of electrons, the system had analogous performances on current density, desalination, and acid and alkali productions with the conventional system. These results meant that the ideal voltage for achieving bipolar membrane and electrochemically active bacteria (EAB) synergism was 1.0 V in the improved MEDCC. In terms of chemical production in the cathode chamber of the MEDCC, the application of H2O2 production increased the rate of return by four times when compared to conventional alkali production. Only about 55% of total consumption was attributed to bioenergy in the substrate, suggesting the system was energy-saving. Therefore, the revised MEDCC had great potential in the field of energy-efficient and green H2O2 generation and desalination whilst maintaining acid and alkali productions.