Bio-electro-fenton process driven by microbial fuel cell for wastewater treatment

In this study, we proposed a new concept of utilizing the biological electrons produced from a microbial fuel cell (MFC) to power an E-Fenton process to treat wastewater at neutral pH as a bioelectro-Fenton (Bio-E-Fenton) process. This process can be achieved in a dual-chamber MFC from which electrons were generated via the catalyzation of Shewanella decolorationis S12 in its anaerobic anode chamber and transferred to its aerated cathode chamber equipped with a carbon nanotube (CNT)/γ-FeOOH composite cathode. In the cathode chamber, the Fenton's reagents including hydrogen peroxide (H 2O 2) and ferrous irons (Fe 2+) were in situ generated. This Bio-E-Fenton process led to the complete decolorization and mineralization of Orange II at pH 7.0 with the apparent first-order rate constants, k app = 0.212 h -1 and k TOC = 0.0827 h -1, respectively, and simultaneously produced a maximum power output of 230 mW m 2 (normalized to the cathode surface area). The apparent mineralization current efficiency was calculated to be as high as 89%. The cathode composition was an importantfactor in governing system performance. When the ratio of CNT to γ-FeOOH in the composite cathode was 1:1, the system demonstrated the fastest rate of Orange II degradation, corresponding to the highest amount of H 2O 2 formed.Department of Civil and Environmental Engineerin