Theoretical and experimental evaluation of the potential-current distribution and the recirculation flow rate effect in the performance of a porous electrode microbial electrolysis cell (MEC)

[Display omitted] •A dynamic mathematical model to describe the performance of a MEC reactor is proposed.•A pseudo-homogenous parametric model in porous media was set.•Concentric configuration produces non-uniform current-potential lines.•Model predicts an increment of total faradaic current with the flow rate.•Experimental data were quantitatively predicted at a high flow rate. Microbial electrolysis cells (MECs) are devices employing a biofilm attached on the anode to oxidize organic matter and generate electrons required for thermodynamically unfavorable reactions arising on the cathode. Because of its complexity, factors such as the number of compartments, the presence of the membrane, as well as the position and electrode geometries play an important role in MEC reactor performance. Mathematical modeling is an effective way to describe the phenomenological role of the above-mentioned factors, nevertheless, many models in the literature do not present a complete description of the influence of operational parameters in its general performance. Henceforth, a parametric 2D dynamic mathematical model to describe the current response of a MEC reactor is proposed and experimentally validated in this work. Operational parameters such as the electrode and current collector configurations, flow rate and potential distribution are considered. The results revealed that the flow rate and current collectors hamper the performance when a typical concentric biologic reactor configuration is used. A flow-through configuration is recommended for further tests.