Electrochemical and Theoretical Concepts of Microbial Electrolysis Cells

The novel combination of electrochemical and microbiological principles found in microbial electrolysis cells (MECs) provides a sustainable means of transforming energy and wastewater disposal. Microbes function as biocatalysts in these cell types, assisting in the anaerobic oxidation of organic matter by producing electrons that transit through an exterior circuit to the cathode generating hydrogen gas. Microbial electron transfers processes, electrode reactions, and microbial metabolism are all deeply ingrained in the theoretical and electrochemical roots of MECs. The fundamental mechanism of MECs is the utilization of extracellular electron transfer-capable bacteria or other electroactive microorganisms for their metabolic processes. Organic substrates are broken down and electrons are released during microbial oxidation, which takes place at the anode. To reach the cathode, where reduction events take place and hydrogen gas is produced, these electrons travel via an external circuit. In order to forecast and maximize MEC performance, theoretical models are essential. These models take into account several aspects like mass transfer, electrochemical characteristics, and microbial kinetics. This chapter shows how MECs can use microbiology and electrochemistry to recover energy and remediate wastewater, with potential applications in renewable energy production and environmental remediation.