Microbial Fuel Cell stack performance enhancement through carbon veil anode modification with activated carbon powder

Iwona Gajda,John Greenman,Ioannis Ieropoulos

doi:10.1016/j.apenergy.2019.114475

Iwona Gajda, John Greenman + Show 1 more

Open Access

https://doi.org/10.1016/j.apenergy.2019.114475

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Abstract

The chemical energy contained in urine can be efficiently extracted into direct electricity by Microbial Fuel Cell stacks to reach usable power levels for practical implementation and a decentralised power source in remote locations. Herein, a novel type of the anode electrode was developed using powdered activated carbon (PAC) applied onto the carbon fibre scaffold in the ceramic MFC stack to achieve superior electrochemical performance during 500 days of operation. The stack equipped with modified anodes (MF-CV) produced up to 37.9 mW (21.1 W m−3) in comparison to the control (CV) that reached 21.4 mW (11.9 W m−3) showing 77% increase in power production. The novel combination of highly porous activated carbon particles applied onto the conductive network of carbon fibres promoted simultaneously electrocatalytic activity and increased surface area, resulting in excellent power output from the MFC stack as well as higher treatment rate. Considering the low cost and simplicity of the material preparation, as well as the outstanding electrochemical activity during long term operation, the resulting modification provides a promising anode electrocatalyst for high-performance MFC stacks to enhance urine and waste treatment for the purpose of future scale-up and technology implementation as an applied off-grid energy source.

Highlights

Microbial Fuel Cell is a type of bioelectrochemical device that employs electroactive microorganisms to transform chemical energy into direct electricity by means of a combination of microbial metabolic and electrochemical reactions from a variety of substrates [1] including wastewater [2] and urine [3]
powdered activated carbon (PAC)-based cathodes are widely applied in MFC studies including field trials and prototypes of the membrane-based [8] and membrane-less systems [9] and its properties suggest it would be an excellent candidate to adopt in the biotic anode because of the micronanostructrure of the activated carbon powder particles
This work aims to explore for the first time, simple and inexpensive modification of the anodic carbon veil scaffold with the addition of powdered activated carbon onto the fibres to produce a three-dimensional (3D) structure in order to improve the output of a MFC stack

Summary

Introduction

Microbial Fuel Cell is a type of bioelectrochemical device that employs electroactive microorganisms to transform chemical energy into direct electricity by means of a combination of microbial metabolic and electrochemical reactions from a variety of substrates [1] including wastewater [2] and urine [3]. This work aims to explore for the first time, simple and inexpensive modification of the anodic carbon veil scaffold with the addition of powdered activated carbon onto the fibres to produce a three-dimensional (3D) structure in order to improve the output of a MFC stack It aims to test the MFC performance, as a result of this modification, over a long term period (500 days) under feeding and starvation regimes and discusses scale-up challenges for wider implementation. This is in order to aid the development of an affordable system that is designed for the ease of mass production of future urine-powered systems deployed as decentralised energy sources in a wide range of real world environments. In order for MFCs to be fully realised as off-the-grid power sources, research must focus on producing low cost and easy to manufacture electrode and membrane materials, which have been tested in realistic environments

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