Improvement of Microbial Fuel Cell Performance by Selection of Anodic Materials and Enrichment of Inoculum

Abstract

This work aimed at evaluating the effect of four anodic materials and the use of enriched inocula on the microbial fuel cell (MFC) performance. The anodic materials were granular activated carbon (GAC), graphite rod (GR), triangles of graphite (GT) and graphite flakes (GF). When loaded with a sulfate-reducing inoculum (SR-In) the internal resistance (Rint) obtained were 273, 410 and 795 Ω for GF, GT, GR, respectively and higher than 10 000 Ω for GAC, whereas the maximum volumetric power (PV,max) were 1326, 2108 and 3052 mW m-3 for GR, GT and GF, respectively. We observed a decrease of Rint and an increase of PV,max with the increase of the log of A´s of the graphite anodic materials that was consistent with a mathematical model previously reported by our Group. The use of the Fe (III)-reducing inoculum significantly enhanced the MFC performance; PV,max was up to 5000 mW m-3, 40% higher than the power obtained with SR-In whereas the Rint was 140 ohms. Highest PVs of our MFC were close to values of electricity power derived from the anaerobic digestion of municipal wastewaters. In this regard, results of this work point out to a promising approach to further tapping bioelectricity from organic wastes that previously have yielded biohydrogen.

Less is More: A Comprehensive Study on the Effects of the Number of Gas Diffusion Layers on Air–Cathode Microbial Fuel Cells

“…to produce a high current [7] that would lead to high power in addition to wastewater oxidation. Several authors have studied the factors that can increase the power of an MFC such as the microbial inoculum, the internal and external cell resistances, the ionic strength of the culture medium and the electrode materials [8,9] …”