Improving Bioelectricity Generation of Microbial Fuel Cell (MFC) With Mediators Using Kitchen Waste as Substrate

Abstract

The enhancement of bioelectricity generation in the Microbial Fuel Cell (MFC) necessitated the introduction of exogenous compound (s) (i.e.mediators).The effect of 1ml of various synthetic exogenous mediators including dyes and metallorganics such as Ethylene Diamine Tetra Acid [EDTA], potassium ferricyanide [K 3 Fe(CN) 6 ], methylene blue [MB], neutral red [NR] and potassium permanganate [KMnO 4 ] was investigated in a 21day study during electricity generation in an MFC.The maximum Power Density (PD) obtained without the addition of any mediator was 84.58mW/m 2 , while those MFCs which utilized mediators recorded higher energy yield.The highest power density and percentage energy contribution of 924.79mW/m 2 (993.39%) was obtained using K 3 Fe(CN) 6, while values obtained with EDTA [803.71mW/m 2 (850.24%)];MB [340.45mW/m 2 (302.52%)] and KMnO 4 [192.14mW/m 2 (121.17%)] as mediators were appreciably higher.Further study on the use of these mediators showed inhibitory effects with the % reduction of microbial load in the following trend as MB (4.96%) < EDTA (6.13%) < NR (11.67%) < Ferricyanide (19.16%) < KMnO 4 (21.89%) when compared to the control.Although the application of mediators improved energy production, minimum inhibitory concentration of the mediators should be ascertained to prevent the eradication of electrogens during electricity production.