Pierpaoli V., Notari B., Zeppilli M., Villano M., 2024, Bioelectrochemical Organic Matter Conversion Into Hydrogen, Comparison of Different Polarization Strategies, Chemical Engineering Transactions, 110, 217-222.
Hydrogen plays a pivotal role in the decarbonization of the fuel industry as both an energy vector and a chemical, however most of the available technologies still heavily rely on fossil fuels and sustainable processes are still unused due to their higher operational costs. MECs are devices based on the utilization of electroactive microorganisms that can interact with polarized electrodes (usually graphite-based), using them as the final electron acceptor for their metabolism. The use of a bioanode capable of oxidizing the organic substances contained in wastewater makes it possible to utilize part of the chemical energy present in the reduced waste compounds for the generation of green hydrogen, reducing the required (theoretical) potential by 85% compared to conventional electrolysis (+1.23 V vs +0.187 V). This study aims to compare two different polarization strategies of a microbial electrolysis cell aimed at hydrogen production coupled with the oxidation of synthetic wastewater. The study clearly showed the advantage of using potentiostatic polarization over galvanostatic polarization due to lower energy consumption during the potentiostatic polarization mode. Indeed, galvanostatic polarization promoted the loss of biological activity due to kinetic limitations in the biological reactions. Consequently, water oxidation on graphite granules occurred in the anodic chamber, increasing the anodic potential up to 0.95 V vs. SHE.
