Biofilm distribution and performance of microfluidic microbial fuel cells with different microchannel geometries

摘要

Laminar-flow controlled microfluidic microbial fuel cells (MMFCs) are presented and investigated by using three different microchannel geometries including the converging channel, the straight channel and the diverging channel. The biofilm distribution along the microchannel is visualized. The effects of microchannel geometry on the start-up process and cell performance are also evaluated. The results show that the MMFC with a diverging channel (MMFC-D) begins to generate current in the shortest time compared with MFCs with a converging channel (MMFC-C) and a straight channel (MMFC-S). Moreover, the maximum power density (2447.7 ± 38.9 mW/cm~2) of MMFC-D is 429% and 24% higher than that of MMFC-C (462.7 ± 17.5 mW/cm~2) and MMFC-S (1980.1± 27.5 mW/cm~2), respectively. The high performance of MMFC-D can be explained by the combined effect of the good and uniform attached biofilm and the low anode resistance, which significantly depends on the microchannel geometry.