Power Generation and Electrochemical Analysis of Biocathode Microbial Fuel Cell Using Graphite Fibre Brush as Cathode Material

Abstract

To improve cathodic efficiency and sustainability of microbial fuel cell (MFC), graphite fibre brush (GFB) was examined as cathode material for power production in biocatalysed‐cathode MFC. Following 133‐h mixed culturing of electricity‐producing bacteria, the MFC could generate a reproducible voltage of 0.4 V at external resistance (REX) of 100 Ω. Maximum volumetric power density of 68.4 W m–3 was obtained at a current density of 178.6 A m–3. Upon aerobic inoculation of electrochemically active bacteria, charge transfer resistance of the cathode was decreased from 188 to 17 Ω as indicated by electrochemical impedance spectroscopy (EIS) analysis. Comparing investigations of different cathode materials demonstrated that biocatalysed GFB had better performance in terms of half‐cell polarisation, power and Coulombic efficiency (CE) over other tested materials. Additionally, pH deviation of electrolyte in anode and cathode was also observed. This study provides a demonstration of GFB used as biocathode material in MFC for more efficient and sustainable electricity recovery from organic substances.

Cathode materials evaluation in microbial fuel cells: A comparison of carbon, Mn2O3, Fe2O3 and platinum materials

“…Power densities of 24.7 and 68.4 W m −3 were achieved with biocathodes based on graphite fiber brushes [35,39]. Differences in power densities can be attributed to the operation conditions, MFC design and cathode surface area.…”

Microbial Fuel Cells, A Current Review

“…The performance of a wet air cathode inoculated with a consortium of sludge and sediment microbes was increased through the interactions of the microorganisms on the cathode surface [131,139]. The use of a biocathodes has also been reported to reduce charge transfer resistance of the cathode from 188 to 17 ohms [140] and 40.2 to 12 ohms [141]. Microbial community analysis of the biocathode has identified a wide range of organisms present in the anode community including representatives of the divisions: Betaproteobacteria, Bacteroidetes, Alphaproteobacteria, Chlorobi, Deltaproteobacteria, Actinobacteria, and Gammaproteobacteria [141].…”

Microbial Conversion of Biomass: a Review of Microbial Fuel Cells

“…Synthetic membranes include anion exchange membranes, cation exchange membranes and ultra filtration membranes. Studies have shown that anion exchange membranes perform better than cation exchange membranes due to a lower resistance (You et al, 2009) . These types of membranes are generally very expensive, have high minimum orders or incur large freight charges as they are only manufactured overseas.…”

“…The platinum acts as a catalyst and is necessary to enhance the rate of reduction of oxygen at the cathode . As platinum is highly expensive and can be poisoned by components of the substrate solution You et al, 2009) www.intechopen.com it is desirable to eliminate it from MFCs and MECs altogether. Several alternatives have been investigated including chemical catholytes, biocathodes and transitional metals (He & Angenent, 2006).…”