Bio-Electrochemical Sensor for Fast Analysis of Assimilable Organic Carbon in Seawater

Abstract

A Microbial Fuel Cell (MFC) based biosensor for the determination of Assimilable Organic Carbon (AOC) inseawater was developed by establishing an anodophilic marine biofilm on the surface of an electrode poised at +250mV (vs Ag/AgCl) rather than the traditionally used potentials of about -300 mV. A linear correlation (R2>0.99)between electrochemical signals (peak current) and acetate concentration ranging 10 to 55 μM was achieved.Usingthe positive anodic potential enabled the rapid establishment of the electrochemically active anodophilic biomasswithin a period of less than 8 days, a higher sensitivity (0.017 mA/μM acetate added) and a lower detection limit (2.5μM acetate, 0.16 mg O2/L of Biological Oxygen Demand (BOD)) compared to the negative anodic potential. Further,it was shown that this bio-electrochemical AOC sensor could tolerate the presence of low concentrations ofdissolved oxygen. The established potentiostat controlled MFC biosensor could be used for the purpose of onlinewater quality monitoring for seawater desalination plants prone to biofouling of RO membranes.