title: Characterization and optimization of cathodic conditions for H2O2 synthesis in microbial electrochemical cells.
abstract: Cathode potential and O2 supply methods were investigated to improve H2O2 synthesis in an electrochemical cell, and optimal cathode conditions were applied for microbial electrochemical cells (MECs). Using aqueous O2 for the cathode significantly improved current density, but H2O2 conversion efficiency was negligible at 0.3-12%. Current density decreased for passive O2 diffusion to the cathode, but H2O2 conversion efficiency increased by 65%. An MEC equipped with a gas diffusion cathode was operated with acetate medium and domestic wastewater, which presented relatively high H2O2 conversion efficiency from 36% to 47%, although cathode overpotential was fluctuated. Due to different current densities, the maximum H2O2 production rate was 141 mg H2O2/L-h in the MEC fed with acetate medium, but it became low at 6 mg H2O2/L-h in the MEC fed with the wastewater. Our study clearly indicates that improving anodic current density and mitigating membrane fouling would be key parameters for large-scale H2O2-MECs.
authors.affiliation: Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L3G1, Canada.
authors.forename: Junyoung
authors.initials: J
authors.lastname: Sim
authors.affiliation: Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L3G1, Canada.
authors.forename: Junyeong
authors.initials: J
authors.lastname: An
authors.affiliation: Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L3G1, Canada.
authors.forename: Elsayed
authors.initials: E
authors.lastname: Elbeshbishy
authors.affiliation: National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, USA.
authors.forename: Hodon
authors.initials: H
authors.lastname: Ryu
authors.affiliation: Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L3G1, Canada. Electronic address: hyungsool@uwaterloo.ca.
authors.forename: Hyung-Sool
authors.initials: HS
authors.lastname: Lee
mesh_terms: D000085:Acetates / Q000032:analysis; D001674:Bioelectric Energy Sources; D057919:Biological Oxygen Demand Analysis; D004058:Diffusion; D004563:Electrochemistry; D004566:Electrodes; D005740:Gases / Q000032:analysis; D006108:Graphite / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000378:metabolism*; D010100:Oxygen / Q000032:analysis; D013997:Time Factors; D062065:Wastewater / Q000737:chemistry
chemical_list: D000085:Acetates; D005740:Gases; D006108:Graphite; D006861:Hydrogen Peroxide; D010100:Oxygen; D062065:Wastewater
keywords: Cathode potential; Gas diffusion; Hydrogen peroxide; Microbial electrochemical cell; Microbial fuel cell