Carbon veil anode for microbial fuel cells: Comparing the performances of biocatalyst-modified anodes with large-area anodes

Extra cellular electron transfer (EET) taking place between microbes and anodes serve crucial in improving MFC performance. Enhancing both biocompatibility and electron conductivity of anodes is crucial for boosting EET efficiency, and biomass-derived electrocatalysts present a cost-effective solution to achieve these improvements. The micro/mesoporous biocatalyst derived from Mango Seed Hull (MSH), with a surface area of 1018.8 m2/g and a pore volume of 0.49 cm3/g, exhibited graphitic carbon characteristics and pyrrolic nitrogen content, enhancing electron conductivity. The electrode surface was characterized by the presence of hydrophilic functional groups -OH, -COOH, -NC which increased its biocompatibility. The biocatalyst-modified CV electrodes exhibited very good anodic capacitance corresponding to a loading of 2 mg/cm2 with a value of 115.65 mF/cm2 when compared to 26.83 mF/cm2 as in the case of bare CV. The electrode produced a maximum power density of 3.34 W/m3 when used as anode in an MFC which was almost a 17.5-fold increase compared to plain CV anode MFC. Increasing the anode surface area without biocatalyst modification led to a rise in ohmic resistance, reaching a maximum of 17.83 Omega for a 15-fold area increase. The highest power performance, 2.88 W/m3, was achieved with a 10-fold increase in surface area. The study confirmed the superior performance of biocatalyst-modified electrodes compared to the large area anode and proposes the scope of biocatalyst modification of CV anode for MFC scaleup in reducing the reactor footprint.