Microfluidic membraneless microbial fuel cells: new protocols for record power densities

Abstract

In addition to offering a promising approach for niche applications in environmental sensing and portable power sources, microfluidic microbial fuel cells (MFCs) can also accelerate the development of mainstream energy...

Optimization of Microbial a Fuel Cell with Linear Sweep Voltammetry and Microfluidics

“…The normalized power densities may be significantly higher than reported above. While normalizing by projected electrode area is typical in microfluidic MFCs literature, we have recently shown that not all of the electrode surface area is useful for EAB growth in side-by-side electrodes [5]. Rather, as previous authors have demonstrated, outputs can be limited by bottlenecks in the electrolyte contact area between the anode and cathode chambers [32,33].…”

“…No overshoot was observed at any time, indicating that the EAB was not stressed by oxygen accumulation or from exposure to ferricyanide crossover from the catholyte co-flow stream. We credit this to the improved fluid delivery system, which avoided crossover of the catholyte to the anode chamber [5]. From an analysis of the polarization curves at 50 h in Figure 2a, several indicators showed that performance was improved as the EAB matured.…”

“…The phosphate buffer solution with a pH of 7 was prepared by mixing 2.290 g L -1 of Na2HPO4 and 2.256 g L -1 of NaH2PO4 to obtain a final concentration of 30 mM. Both the anolyte and catholyte inlets were connected to a 4-way valve for easy exchange of syringes without interruption [5].…”

“…We leave this question for future studies, but for now, we note that QT=20 mL h -1 produced electrode areal-normalized outputs that were only slightly improved over those obtained at 3 mL h -1 . Considering the improved fluid management that results in higher acetate conversion at low flow rates [5], 3 mL h -1 is considered an excellent option for optimized operation. We credit the lower sensitivity to flow rate originating from the optimized placement of electrodes away from the channel wall, resulting in a more uniform flow field being applied to the electrode-adhered EAB.…”

“…Additionally, wastewater treatment has been demonstrated using an increasing number of substrate molecules, thus opening the door to implications for a large range of potential industries [3]. Microfluidics is becoming a new option for study and development of MFCs, with results that are transferable to prevailing larger-scale systems [4,5]. Especially important is that they are flow-based and can, thus, maintain concentration conditions due to constant replenishment of nutrient liquids [4,6].…”