Algal-Mediated Carbon Dioxide Separation in Biological Hydrogen Production

The production of hydrogen via dark fermentation generates carbon dioxide, which needs to be separated and re-utilized to minimize the environmental impact. This research investigates the potential of utilizing algae for carbon dioxide sequestration in hydrogen production via dark fermentation. However, algae alone cannot fully use all the carbon dioxide produced, necessitating the implementation of a multistage separation process. This study proposes a purification approach that integrates membrane separation with a photobioreactor in a multistage design layout. Mathematical models were used to simulate the performance efficiency of multistage design layout using MATLAB 2015b (Version 9.3). A detailed parametric analysis and the key parameters influencing the separation efficiency were conducted for each stage. This study explores how reactor geometry, operational dynamics (such as gas transfer rates and light availability), and algae growth impact both CO2 removal and hydrogen purity. An optimization strategy was used to obtain the set of optimal operating and design parameters. Our results have shown a significant improvement in hydrogen purity, increasing from 55% to 99% using this multistage separation process, while CO2 removal efficiency rose from 35% to 85% over a week. This study highlights the potential of combining membrane technology with photobioreactors to enhance hydrogen purification, offering a more sustainable and efficient solution for hydrogen production.