Microbial electrolysis cells designed for BioH2 production: Potential improvements with carbon dioxide and nitrogen

Abstract

The long-term feasibility and efficiency of microbial electrolysis cells (MECs) depend primarily upon several crucial parameters. However, they show promise for sustainably producing biohydrogen (bioH2). This study investigates a newly designed biohydrogen reactor by studying the effects of several variables on the production of bioH2, including applied voltage, electrode material, and gas sparging with CO2 and N2. The study aims to optimize the system for improved efficiency and production performance. The results of this study show that both electrode type and applied voltage affect bioH2 production where choosing the right inoculum has a significant impact on the catalytic efficiency. The aluminum electrodes significantly help produce the most bioH2 production at 2.0 V with 884 mL/L in 11.25 min, while emphasizing the significance of material characteristics. The reduced partial pressure from CO2 sparging, up to a point, improves bioH2 generation. The N2 gas sparging further demonstrates an increased efficiency where the ideal flow rates are dependent on the size of the MEC system. The highest bioH2 production rates for CO2 and N2 sparging are measured as 821 mL/L and 813 mL/L in 4.25 min and 11.50 min at a volume of 400 mL/min and 300 mL/min, respectively. The results of this study further advance our knowledge of and ability to optimize MEC systems for long-term, sustainable bioH2 production.