Tailoring flow straighteners’ architectures through additive manufacturing to enhance power performance and scale-up microbial fuel cell technology

Abstract

In an aim to scale up the microbial fuel cell (MFC), this research is a first attempt to investigate the impact of two lattice structures flow straighteners: gyroid and X lattice to compare with the conventional honeycomb flow straightener, fabricated via additive manufacturing. The study focused on assessing their effect on the degradation of domestic wastewater and power generation in a dual chamber recirculation MFC. Other than the geometry, structures were also tested at flow rates of 20 mL/min, 60 mL/min, and 100 mL/min. Our study found that MFC equipped with a gyroid structure flow straightener produced the highest power density of 2871.89mWm−2, followed by the X lattice flow straightener of 2626.56 mWm−2 and 2096.03 mWm−2 with honeycomb flow straightener. ANSYS simulations revealed that this increased power density is attributed to the enhanced mixing of wastewater. Traditional honeycomb-based flow straighteners showed straight streamlines, causing bacteria to settle and leading to lower output voltage. The novel X lattice and gyroid lattice designs ensured uniform substrate mixing, addressing the issue of substrate settling and consequently boosting the MFC's power performance. An optimized flow rate of 60 mL/min yielded the best output. Overall, this study successfully introduced two novel lattice structures for flow straighteners, demonstrating their potential in enhancing power performance and the scalability of this technology when produced using additive manufacturing.