Three-dimensional electrode microbial fuel cell for hydrogen peroxide synthesis coupled to wastewater treatment

Abstract

A three-dimensional electrode bioelectrochemical system for the cathodic production of hydrogen peroxide and the simultaneous treatment of wastewater is investigated. Three types of three-dimensional electrodes – activated carbon particle electrodes (ACPE), carbon black particle electrodes (CBPE) and graphite particle electrodes (GPE) – are made of activated carbon (AC), carbon black (CB) and graphite powders respectively with polytetrafluoroethene (PTFE) as the binder. The MFC using the GPE is shown to perform best for catalyzing H2O2 production, while the MFCs equipped with the CBPE and the ACPE achieve a 17–18% higher power output but a 2.5–4.4% lower H2O2 yield, due to the further cathodic reduction of H2O2. Furthermore, a relatively high current in the system is demonstrated to have a positive impact on both cathodic H2O2 generation and anodic organic degradation for each MFC. At an external resistance of 20 Ω, the MFC using the GPE achieves the H2O2 generation of 196.50 mg L−1 and 84% COD removal in 24 h, with Coulombic efficiency, Faradic efficiency and COD conversion efficiency of 29%, 70%, and 20%, respectively. This study shows that MFC with carbon three-dimensional electrode is a cost-effective energy-saving bioelectrochemical system for the simultaneous production of hydrogen peroxide and removal of COD.