Inhibiting the growth of microbes on the air-cathode in the microbial fuel cell by using an antimicrobial agent

Abstract

The accumulation of aerobic microorganisms on the air-cathode in a single-chamber-microbial fuel cell can suppress the activity of the catalyst, and result in the reduction of the efficiency of the system. Therefore, a suitable mitigation measure is essential to control the growth of biofouling on the cathode. This study aims to investigate the effectiveness of chloramphenicol as an anti-biofouling agent on Pt-coated cathode. Two microbial fuel cells (MFCs) were used where the first (MFC-1) was a conventional Pt-coated air-cathode as a control, while the other one (MFC-2) with antibiotic mixed Pt-coated air-cathode. Results demonstrate that the maximum generated cell potential of 0.82 V in the control MFC-1 was reduced to 0.62 V after three months of operation due to biofouling development on the Pt-coated air-cathode. Besides, the control system achieved 95% chemical oxygen demand (COD) removal after 5 d of hydraulic retention time (HRT). However, using the newly developed cathode in MFC-2, the system achieved a maximum cell potential of 0.85 V with 95% of COD removal by 10 d HRT. The maximum columbic efficiency (CE) achieved in control MFC-1 and MFC-2 were 8 and 12.5%, respectively. The increment in CE was due to the absence of cathodic aerobic biofilm as well as the removal of COD was solely accomplished by the anodic biofilm. This result shows that the application of the antibiotic coating on the cathode can suppress the growth of cathodic biofouling without interfering with the other bio-electrochemical properties (COD removal, power recovery, pH change) of the system.