Improved oxygen reduction and simultaneous glyphosate degradation over iron phthalocyanine and reduced graphene oxide‒dispersed activated carbon fiber electrodes in a microbial fuel cell

Abstract

Iron phthalocyanine (FePc) and reduced graphene oxide (rGO)‒dispersed activated carbon fiber (ACF) is used for the first time as electrodes in a microbial fuel cell (MFC) for energy generation and biodegradation of glyphosate in wastewater. The FePc-rGO/ACF is studied through various physicochemical characterization techniques. Electrochemical analysis shows a pseudocapacitive behaviour with consistent redox peaks of FePc-rGO/ACF, and a 4 e ‒ pathway for oxygen reduction reaction at the cathode. High maximum current and power densities (∼8050 mA m ˗2 and 1101 mW m ˗2 , respectively) are measured for the whole MFC, with simultaneous ∼80% degradation of glyphosate (30 mg L ˗1 ) and 79% reduction in chemical oxygen demand at the anode. The improved performance of MFC is attributed to the synergistic effects of FePc and rGO and biocompatibility of the material. The present study has successfully demonstrated the FePc-rGO/ACF electrode‒based MFC to be a green bioelectrochemical device for efficient bioelectricity generation and biodegradation of emerging herbicides in wastewater. • Successful inclusion of FePc in rGO and their effective coating over ACF. • FePc-rGO/ACF supported the formation of a dense and uniform biofilm. • 80% degradation of PMG and 79% COD reduction achieved in MFC. • The MFC based on FePc-rGO/ACF generated a high power density of 1101 mW/m 2 . • 4 e ‒ pathway indicated for ORR at the cathode of the MFC.