Wastewater Treatment by Using PEDOT-Coated Carbon Nanofiber Electrodes

Bioelectrochemical Engineers and Materials Scientists from the Cornell University might have developed what seems to be a new, cost-effective electrode material for eliminating pollutants from wastewater.

Carbon nanofibers coated with PEDOT in a scanning electron microscope image. CREDIT: Juan Guzman and Meryem Pehlivaner/Provided.

The Scientists have developed electro-spun carbon nanofiber electrodes and have used a conductive polymer (i.e. PEDOT) to coat the electrodes to be on par with carbon cloth electrodes accessible in the market. Application of the PEDOT coating leads to the growth of Geobacter sulfurreducens, an electrically active layer of bacteria, thereby producing electricity and transferring electrons to the innovative electrode.

The research notes that a surface conducive to the growth of these bacteria is formed by the conducting nanofibers, where the bacteria degrades pollutants in the wastewater and generate electricity.

Electrodes are expensive to make now, and this material could bring the price of electrodes way down, making it easier to clean up polluted water.

Juan Guzman, Co-lead Author of the Study and a Doctoral Candidate in the field of biological and environmental engineering

When viewed using a microscope, the carbon nanofiber electrode looks similar to a kitchen scrubber. Co-lead author Meryem Pehlivaner, M.S. ’13 and a Doctoral Student at Northeastern University at present, collaborated with Senior Author Margaret Frey, Professor of Fiber Science and an Associate Dean of the College of Human Ecology, to synthesize the electrode. Pehlivaner employed carbonization and electrospinning techniques to create the carbon nanofibers. When the electrospinning process is conducted for a few hours, a thick nanofiber sheet is formed, which can be seen with the naked eye.

For the process of using the carbon nanofiber electrodes to simultaneously treat wastewater as well as generate electricity, Pehlivaner collaborated with Guzman and Senior Author Lars Angenent, Professor of Biological and Environmental Engineering.

The high surface area, high porosity, as well as biocompatibility of the adaptable carbon nanofiber electrode enabled it to be used with the bacteria. The Scientists noted that when PEDOT is coated on the electrode, functioning of the material is enhanced.

According to Guzman, wastewater treatment plants do not yet utilize this technique. When used over a large area, the bacteria in the electrode can arrest and digest pollutants in the wastewater flowing through it. This technique enhances the treatment of wastewater by enabling systems to consume less space and improve the productivity.

According to Angenent, ideas like these occur on campuses in which faculty and students readily communicate and collaborate. “This defines radical collaboration,” he stated. “We have fiber scientists talking to environmental engineers, from two very different Cornell colleges, to create reality from an idea—that was more or less a hunch—that will make cleaning wastewater better and a little more inexpensive.”

The study titled “Performance of Electro-Spun Carbon Nanofiber Electrodes With Conductive Poly (3,4-Ethylenedioxythiophene) Coatings in Bioelectrochemical Systems,” will be reported in the Journal of Power Sources on 15th July 2017. The study was supported by the National Science Foundation through Guzman’s graduate research fellowship. Frey and Angenent are faculty fellows at Cornell’s Atkinson Center for a Sustainable Future, where the faculty focus on cross-campus collaboration.

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