The effect of anode hydrodynamics on the sensitivity of microbial fuel cell based biosensors and the biological mechanism

Fluid dynamics in the anodic chamber of a microbial fuel cell (MFC) is a key factor affecting the distribution of substrates and the efficiency of mass transport. However, the effect of hydrodynamics on MFC based biosensor (MFC-Biosensor) sensitivity has not been established. In this study, the three-dimension anode flow field of a two chamber MFC was visualized, and anodic configuration optimized by a reasonable serpentine flow field and inlet/outlet settings. Through optimization, the proportion of the dead zone in the anodic configuration decreased by 14.1%, and the velocity at the anode surface increased by 334.6% with better homogeneity of distribution. Moreover, electricity production and the sensitivity of MFC-Biosensors was improved by 42.0%, 46.1% and 52.3% for the detection of CTC, AVM and Hg, respectively. Biofilm viability analysis further proved that the enhanced surface velocity was of benefit for the permeation of toxicants into anodic biofilms, thus improving the sensor performance.