Semi-industrial scale MFC

After several weeks of construction, our first industrial-scale pilot of MFC has been tested.

Results:

No major technical problems (big thanks to Allec for his technical support)

Some technological lock does not allow us yet to reach high powers. During the first test, the MFC produced continuous current of 50mA with a voltage of 200mV so a power of 10mW.

Several improvements have already been envisaged to improve the performance of this MFC, this will be our work for the coming months. But there is no doubt that this prototype will provide us with a valuable technological tool in the race to alternative energies.

Laboratory scale MFC

Our team has developed a laboratory scale prototype capable of supplying up to 2W/m2 of projected electrode surface with a maximal current density of 10A/m2. This device is constituted by 10 independent MFCs and electricity is generated from the digestion of acetate by marine micro-organisms.

We intend to extend the technology to small units of wastewater treatment that would ensure their own power while increasing speed treatment. These performances are among the best obtained by the many teams who undertake now in that direction, particularly the USA with considerable resources (Universities of Massachusetts, Pennsylvania, Washington…) or Australia with the support of industrial companies (University of Queensland and Forster industry).

Microscopy and 3D Optigrid system

The OptiGrid system from Qioptiq Imaging Solutions is a structured light device that produces confocal quality images in near real time from a standard fluorescence microscope without using laser scanning technology. This cost effective alternative to confocal microscopy is controlled by the Improvision Acquisition Hub and interfaced with Volocity Acquisition. The OptiGrid is fast enough to display a live confocal quality preview as the microscope is focused and will acquire data in 2D or 3D over time.

Here, you can find the 3D structure of an aerobic biofilm developed at the surface of a stainless steel electrode.

N-stat box: interesting tool for tests of comparison

The N'stat box is a potentiostat accessory designed for multi-electrodes cell applications. The most interesting feature of this box is to be configured for cells with several working electrodes, one counter and one reference electrode floating in the same bath. This is a remarkably effective tool to compare different electrodes in a similar environment. For example, here are presented the results obtained with different materials of electrode embedded in sediments.

Experiments led under chronoamperometries

Biofilm colonized electrodes are prepared in electrochemical cells under chronoamperometries (constant potential). Current production increase in function of the time and it is correlated to the development of the biofilm on the working electrode surface. For example, here is presented an electrochemically-active biofilm grown at the surface of a graphite electrode and able to catalyse the oxidation of organic matter present in waste water. The other example shows a cathodic seawater biofilm developed at the surface of a stainless steel coupon with the property to catalyse the oxygen reduction reaction.

Potentiostats and Software from Bio-Logic SA

The LGC – Toulouse is actually equipped with several multi-potentiostats from Bio-Logic SA

- 2 x VSP®: 2 x 4 channels of measurement

- VMP®: 16 channels of measurements

- 4 individual potentiostats with 1 channel

Each potentiostat is piloted by EC-Lab software from Bio-Logic SA

http://www.bio-logic.info/potentiostat/software.html

Biofilm construction under constant polarisation

Electrochemically active biofilms are constructed on working electrodes (graphite, stainless steel, DSA®) under constant polarisation (from -0.5V/ECS to +0.5V/ECS depending of the aim of the study). Experiments are conducted in reactors hermetically closed, with or without gas flow. In reactors, a conventional three-electrode system is implemented with a multi-potentiostat (VMP2 Bio-Logic SA) interfaced with a computer (EC-Lab v.8.3 software, Bio-Logic SA).

New and Emerging Science and Technology (NEST) European project

http://www.ea-biofilms.org/

The European Community granted a financial contribution (NEST) for the implementation of the project Electrochemical control of Biofilm-forming micro-organisms : screening, identification, and design of new knowledge-based technologies. This project began on September 1st, 2004 and finished on August 31st, 2007.

This research allowed scientists to increase their understanding of biofilms, which form naturally on a wide range of surfaces. A multidisciplinary team of researchers from France, Italy, Germany, Belgium and Portugal, has set out, in an EU-funded project, to test a wide range of micro-organisms and identify those which are electrochemically active. Rather than growing new genetically engineered micro-organisms, as other research teams are doing, this team took advantage of natural biodiversity and tested existing microbial fauna. Over a period of two years, they screened a range of media, such as aerobic and anaerobic seawaters. Their aim was to identify the micro-organisms which form EABs through observing their behaviour on different electrodes.

Electrochemically-active biofilms

Recent research has identified the phenomenon of Electrochemically Active Biofilms (EAB). EAB, which can achieve a direct electrochemical connection when they form on a conductive material, may be the basis of a new power source. The EAB phenomenon is gaining great importance through the hope that it can bring a breakthrough in fuel-cell technology. Applications for EAB might include new synthesis routes in biotechnology and food production, new strategies for protecting materials, new biosensors, implanted power sources connected directly to metabolisms, and new therapeutic processes. In short, if the early results can be reproduced widely, the application of EAB could represent a massive take-up of natural power from bacteria in a wide range of fields.

Introduction on Microbial Fuel Cell technology

A microbial fuel cell is a device that converts chemical energy to electrical energy by the catalytic reaction of micro-organisms. A typical microbial fuel cell consists of anode and cathode compartments separated by a cation specific membrane. In the anode compartment, fuel is oxidized by micro-organisms, generating electrons and protons. Electrons are transferred to the cathode compartment through an external electric circuit, and the protons are transferred to the cathode compartment through the membrane. Electrons and protons are consumed in the cathode compartment, combining for example with oxygen to form water. The oxygen reduction reaction might be catalysed on the cathode using mineral catalysts (Pt, Co,…) and biological or microbiological catalysts (Enzyme, Electrochemically-active biofilms).

http://en.wikipedia.org/wiki/Microbial_fuel_cell

About the Chemical Engineering Laboratory

The Chemical Engineering Laboratory (LGC) was created in 1965 and became part of the Centre National de La Recherche Scientifique (CNRS) in 1973. It is also linked to two universities in Toulouse: the Institut National Polytechnique de Toulouse (INPT) and the Paul Sabatier University.

Research is carried out in diverse scientific areas, including reaction engineering, mixing and separation processes, interface and particle interactions, electrochemistry, materials, process systems engineering and industrial engineering. In these areas, more than 200 researchers, engineers and technicians search for solutions and improvements in order to satisfy the needs of the process industries.

http://lgc.inp-toulouse.fr/index.php?lang=en

"MFCs capture energy produced by naturally occurring microbial metabolism and can generate electricity from organic matters such as soil, sediments or different wastes"