Long-term operation of bio-catalyzed cathodes within continuous flow membrane-less microbial fuel cells
Journal
Chemosphere
Journal Volume
266
Date Issued
2021
Author(s)
Abstract
Microorganisms were observed to facilitate cathodic oxygen reduction and enhance cathode performance of microbial fuel cells (MFCs). However, the long-term activity and stability of bio-catalyzed cathode needs to be explored. This study evaluated the long-term performance of bio-catalyzed cathode and iron(II) phthalocyanine (FePc)-catalyzed cathode MFCs through effluent water quality, electricity production and electrochemical impedance spectroscopy (EIS) analysis under different scenarios, including conventional wastewater treatment and energy harvesting using a power management system (PMS). During the continuous operation, both systems demonstrated high chemical oxygen demand and ammonium removal, but bio-catalyzed cathode MFCs could achieve significantly better total nitrogen removal than FePc-catalyzed cathode MFCs. The FePc-coated cathode showed constant cathode potential during the entire operation period, but the biocathode showed varied but step-wise increased cathode potential to achieve more than 500 mV versus the standard hydrogen electrode, likely due to the gradual enrichment of biocathode biofilm. EIS analysis revealed that biocathode had higher ohmic resistance than bare carbon felt cathode but the microbial biofilm could largely decrease polarization resistance of cathode material. Microbial community analysis has shown the presence of nitrifying and denitrifying bacteria in the bio-catalyzed cathode biofilm. When connecting PMS, both bio-catalyzed cathode and FePc-catalyzed cathode MFCs successfully charged a capacitor, but the bio-catalyzed cathode MFC voltage significantly dropped to less than 100 mV after charging for 91 h, and gradually recovered when disconnecting PMS. This study has demonstrated the potential application of oxygen reduction bio-catalyzed cathode MFCs for continuous wastewater treatment and energy harvesting for long period of time. © 2020 Elsevier Ltd
Subjects
Biocathode; Impedance; Iron(II) phthalocyanine; Membrane-less microbial fuel cells; Microbial community; Power management system
SDGs
Other Subjects
Bacteria; Biofilms; Catalysis; Cathodes; Chemical oxygen demand; Chemicals removal (water treatment); Denitrification; Effluent treatment; Effluents; Electrochemical impedance spectroscopy; Electrolytic reduction; Energy harvesting; Iron compounds; Iron metallography; Nitrogen removal; Ohmic contacts; Oxygen; Quality control; Wastewater treatment; Water quality; Cathodic oxygen reduction; Continuous wastewater treatment; Electricity production; Microbial community analysis; Microbial fuel cells (MFCs); Polarization resistances; Power management systems; Standard hydrogen electrodes; Microbial fuel cells; ammonia; carbon; iron derivative; nitrogen; oxygen; phthalocyanine derivative; ammonium; biofilm; chemical oxygen demand; effluent; fuel cell; hydrogen; nitrogen; pollutant removal; wastewater treatment; biocatalysis; chemical oxygen demand; denitrifying bacterium; effluent; electric potential; electricity; electrochemical analysis; impedance spectroscopy; microbial community; microbial fuel cell; nitrifying bacterium; nonhuman; polarization; reduction (chemistry); waste water management; water quality; biochemical oxygen demand; bioenergy; catalysis; electrode; Bioelectric Energy Sources; Biological Oxygen Demand Analysis; Catalysis; Electricity; Electrodes
Type
journal article