Preparation of Microbially Reduced Graphene Oxide and Its Application in Bioelectrochemical Systems
This study focused on the optimal strategy for microbial reduced graphene oxide (MRGO) modified carbon felt electrodes via the green pathway of PCA reduced graphene oxide reducing graphene oxide (GO), and examined its impact on bioelectrochemical systems (BES). It was proved that the optimal preparation strategy for MRGO modified carbon felt was 0.6 mg/mL GO, inoculation of G. sulfurreducens followed prior to GO and three sequential G. sulfurreducens inoculations, resulting in the formation of a G. sulfurreducens -MRGO-G. sulfurreducens sandwich structure. The electrical energy output of MRGO modified microbial fuel cell (MFC) anode was 323.95% higher than that of biologically modified MFC anode, and it had a faster electron transfer rate and stronger charge storage capacity. The electron amount recovered from butyrate by MRGO modified MFC anodes was 4 times higher than that by biologically modified MFC anode. In addition, the butyrate and hexanoate yields of the MRGO modified microbial electrolysis cell (MEC) cathode were 4 and 14.8 times higher than those of the biomodified MEC cathode, respectively. Among the three applied voltage conditions of 0.5 V, 0.7 V, and 0.9 V, 0.7 V was the optimal voltage for the production of high-even carbon volatile fatty acids (VFAs) by the MRGO modified MEC cathode. MRGO modified electrodes increase the relative abundance of electroactive bacteria and acid-producing bacteria in the BES reactor. This study clarifies the preparation method of MRGO modified electrodes, elucidates the potential and mechanism of MRGO modified electrodes to improve BES performance.