Biotic Cathode of Graphite Fibre Brush for Improved Application in Microbial Fuel Cells.

Siti Farah Nadiah Rusli,Mimi Hani Abu Bakar,Kee Shyuan Loh,Mohd Shahbudin Masdar,Siti Mariam Daud

doi:10.3390/molecules27031045

Siti Farah Nadiah Rusli, Mimi Hani Abu Bakar + Show 3 more

Open Access

https://doi.org/10.3390/molecules27031045

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Abstract

The biocathode in a microbial fuel cell (MFC) system is a promising and a cheap alternative method to improve cathode reaction performance. This study aims to identify the effect of the electrode combination between non-chemical modified stainless steel (SS) and graphite fibre brush (GFB) for constructing bio-electrodes in an MFC. In this study, the MFC had two chambers, separated by a cation exchange membrane, and underwent a total of four different treatments with different electrode arrangements (anodeǁcathode)—SSǁSS (control), GFBǁSS, GFBǁGFB and SSǁGFB. Both electrodes were heat-treated to improve surface oxidation. On the 20th day of the operation, the GFBǁGFB arrangement generated the highest power density, up to 3.03 W/m3 (177 A/m3), followed by the SSǁGFB (0.0106 W/m3, 0.412 A/m3), the GFBǁSS (0.0283 W/m3, 17.1 A/m3), and the SSǁSS arrangements (0.0069 W/m−3, 1.64 A/m3). The GFBǁGFB had the lowest internal resistance (0.2 kΩ), corresponding to the highest power output. The other electrode arrangements, SSǁGFB, GFBǁSS, and SSǁSS, showed very high internal resistance (82 kΩ, 2.1 kΩ and 18 kΩ, respectively) due to the low proton and electron movement activity in the MFC systems. The results show that GFB materials can be used as anode and cathode in a fully biotic MFC system.

Highlights

Microbial fuel cells (MFCs) are environmentally friendly devices where carbonaceous materials become the biomass for electricity generation
We reported the observation on the effect of combined materials between the graphite fibre brush (GFB) and the stainless steel (SS) electrodes and the non-chemical surface modification of GFB in MFC application
The measured open circuit voltage (OCV) of the GFB GFB system was recorded at 0.56 V (Figure 1A), which was lower than that of SS SS (0.64 V) and GFB SS (0.58 V) by 13% and 19%, respectively

Summary

Introduction

Microbial fuel cells (MFCs) are environmentally friendly devices where carbonaceous materials become the biomass for electricity generation. Transferring electrons from the anode to the cathode generates electrical power and reduces organic waste. This type of fuel cell shows a double benefit over other devices since energy production and treatment coincide. The use of MFCs for electricity generation with wastewater has already been widely reported in the literature [3,4]. An MFC uses microorganisms as biocatalysts at the anode, while platinum is usually used as the catalyst for the cathode. The application of the platinum catalyst adds a significant limitation to MFC application and economic viability. Zhang et al conducted a comparison study of materials for an MFC biocathode including graphite felt, stainless steel (SS) mesh and carbon paper [8]

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