Bioanode as a limiting factor to biocathode performance in microbial electrolysis cells

The bioanode is important for a microbial electrolysis cell (MEC) and its robustness to maintain its catalytic activity affects the performance of the whole system. Bioanodes enriched at a potential of +0.2 V (vs. standard hydrogen electrode) were able to sustain their oxidation activity when the anode potential was varied from -0.3 up to +1.0 V. Chronoamperometric test revealed that the bioanode produced peak current density of 0.36 A/m(2) and 0.37 A/m(2) at applied potential 0 and +0.6 V, respectively. Meanwhile hydrogen production at the biocathode was proportional to the applied potential, in the range from -0.5 to -1.0 V. The highest production rate was 7.4 L H-2/(m(2) cathode area)/day at -1.0 V cathode potential. A limited current output at the bioanode could halt the biocathode capability to generate hydrogen. Therefore maximum applied potential that can be applied to the biocathode was calculated as -0.84 V without overloading the bioanode. (C) 2017 The Authors. Published by Elsevier Ltd.