A team of researchers from the Iowa State University in Ames, IA has demonstrated a proof-of-concept three-dimensional paper-based microbial fuel cell (MFC) that could take advantage of capillary action to guide the liquids through the MFC system and to eliminate the need for external power. Their report appears in the forthcoming issue of the journal TECHNOLOGY.
The paper-based MFC runs for five days and shows the production of current as a result of biofilm formation on anode. The system produces 1.3 μW of power and 52.25 μA of current yielding a power density of approximately 25 W/m3 for this experiment.
The device allows flow of the streams of Shewanella Oneidensis MR-1 (yellow) and the Potassium Ferricyanide (white) into the chambers. Proton exchange membrane is placed between the two chambers to separate the two liquids as well as allow the positively charged ions released in the biocatalytic breakdown of the anolyte to flow from the anode to the cathode.
These results show that the paper-based microbial fuel cells can create power in an environmentally friendly mode without the use of any outside power. "All power created in this device is useable because no electricity is needed to run the fluids through the device. This is crucial in the advancement of these devices and the expansion of their applications." says Nastaran Hashemi, PhD, Assistant Professor of Mechanical Engineering and the senior author of the paper.
The biofilm formation on the carbon cloth during the test provides further evidence that the current measured was the result of the bio-chemical reaction taking place. This is important because the biofilm plays a vital role in current production of a microbial fuel cell. Increased biofilm size and thickness ultimately leads to increased current production. Individual bacterial cells metabolize electron-rich substances in a complex process involving many enzyme-catalyzed reactions. The electrons are then free to travel to the anode through one of many modes of electron transport.
Electron transport is very complicated, and evidence suggests that it is unique to each type of bacteria. For Shewanella Oneidensis MR-1, the most predominantly known ways of shuttling electrons from the individual bacteria cells to the anode are through direct contact, excreted soluble redox molecules, and biological nanowires.
Of these, it is widely believed that excreted soluble redox molecules serving as extracellular electron shuttles makes up for as much as 70% of electron transfer mechanisms from individual bacterial cells to the electrode. Moreover, it is shown that direct contact between individual S. Oneidensis MR-1 and the electrode has little impact on the current generation, supporting a mediated electron transfer mechanism. Biofilm helps with the adsorption of the redox molecules to the electrode, which makes it important to have in high power density microbial fuel cells.
There are not many studies on power production from paper-based microbial fuel cells running for few days. Without enough time for biofilm to form, the reported current and power data would predominantly be associated with extracellular electron transfer, which represents does not fully represent electrical producing capabilities of microbial fuel cells. This device for the first time demonstrates the longer duration of use and ability to operate individually, a development that could help increase the number of situations where microbial fuel cells can be applied.
The Iowa State University team is currently exploring options to better control the voltage output and create constant current. Controlled environment tests will aid in the regulation of the systems output and yield more stable results. For optimal usability and decrease in cost, the team would also like to explore a device that would not need to use Nafion and Potassium Ferricyanide in its application. Additional co-authors of the paper are Niloofar Hashemi, Joshua Lackore, Farrokh Sharifi, Payton Goodrich, and Megan Winchell.
This work was partially funded by Iowa State University and the William March Scholar fund. We would like to thank Ashley Christopherson, Peter Meis, and Luke Wagner for their assistance with this project.
Philly Lim | EurekAlert!
Researchers use light to remotely control curvature of plastics
23.03.2017 | North Carolina State University
TU Graz researchers show that enzyme function inhibits battery ageing
21.03.2017 | Technische Universität Graz
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy