Modeling of Multi-population Microbial Fuel and Electrolysis Cells Based on the Bioanode Potential Conditions

Abstract

Microbial fuel cell and microbial electrolysis cell are two major types of microbial electrochemical cells. In the present study, we governed modeling of these systems by concentrating on the simulation of bioelectrochemical reactions in both biofilm and anolyte and considering the effect of pH on the microbial growth. The simulation of microbial fuel and electrolysis cells can be described by shifting the bioanode surface potential boundary conditions. Model validation was performed using experimental results from the MFCs fed with cheese whey wastewater and then it was switched to a supposed microbial electrolysis cell. The effect of applied voltage as well as poising the cathode surface potential on the anode surface potential and microbial population have been acquired. The results show that hydrogen production rate increases at the higher applied voltage and cathode potential, but the influence of cathode potential at the applied voltage of 0.9 V was much more tangible. The MFC was simulated in different pH values to optimize the power generation. The maximum of power output at 100 Ω was obtained in pH 7.5. In addition, the microbial behavior in the biofilm and anolyte was investigated as a strong function of pH. Due to the higher growth rate of electrogens, the optimum pH for the mixed culture of electrogens was the same for the pure culture (pH 7.7), but it is alterd for acetoclstic methanoges.