Impact of CO2 Flow Rate and Nutrient Augmentation on the Production of Bioelectricity in a Photosynthetic Microbial Carbon Capture Cell

Abstract

This study investigates the potential of microbial carbon capture cells (MCCs) as a promising solution for energy generation and carbon capture. MCCs comprise two cylinders of plexiglass cells that serve as anode and cathode compartments (both utilize platinum mesh electrodes) and are separated by an ion exchange membrane (AMI-7001). Synechococcus is used as a photosynthetic microorganism in the cathode compartment, which plays a role in carbon dioxide (CO2) sequestration. Various factors, such as CO2 flow rate, nutrient augmentation, and light-dark cycles (16:8) (16 hours of light: 8 hours of darkness), were investigated for their impact on MCC performance. The results demonstrate that the high performance of MCC, presenting in a maximum output voltage, was obtained at a CO2 flow rate of 1.5 L/h as optimal conditions with 539 mV compared to 469 and 407 mV at a flow rate of 3 L/h and 4.5 L/h, respectively. Increasing the CO2 flow rate positively influenced power generation, with the highest power density of 22 mW/m2 achieved at a flow rate of 4.5 L/h. Nutrient augmentation was critical in enhancing power density, leading to an impressive outcome of 43.87 mW/m2. Enough illumination has been discovered as an important component in boosting higher voltage and power output. The study also looked at the development of microalgae growth in MCCs, employing absorbance to determine concentration. It was revealed that the kind of Synechococcus had considerable expansion in growth over time.  This investigation provides helpful information about the factors affecting voltage output and biomass growth within MCCs. Optimizing carbon dioxide (CO2) flow rates, nutrition supplementation, and exposure to light appear to be essential requirements for enhancing power generation performance and permitting a long-term capture of carbon in microbial carbon capture cells.