Impact of liquid velocity and stacking modes on the performance of anaerobic fluidized bed microbial fuel cell

Abstract

A stacked anaerobic fluidized bed microbial fuel cell (AFB-MFC) consisting of 10 individual air-cathode MFCs was constructed to measure its power generation performance at different liquid velocities and stacking modes. Open-circuit voltages produced in parallel and series connection modes were observed to reach the peak value of 617.6 mV and 5.3 V, respectively, at the liquid velocity of 7.5 mm/s. In series mode, the stacked AFB-MFC had the highest power density of 3440.1 mW/m2. The chemical oxygen demand removal rate of the stacked AFB-MFC under series connection reached up to 96.87%, slightly higher than that under the parallel condition. The results illustrated that a proper liquid velocity can effectively improve the mass transfer efficiency of the stacked AFB-MFC, while mitigating the internal resistance. By putting the stacked MFCs in series connection mode, voltage losses are evident, indicating that high internal resistances lead to the generation of a parasitic cross current.