New research helps eliminate dead zones in desalination technology and beyond

Engineers have discovered a method to get rid of the fluid circulation “dead zones” that plague the forms of electrodes used for battery-based seawater desalination. The brand new method makes use of a physics-based tapered circulation channel design inside electrodes that strikes fluids shortly and effectively, probably requiring much less vitality than reverse osmosis strategies at the moment require.

Technical hurdles have prevented the wide-scale implementation of desalination know-how. Probably the most-used technique, reverse osmosis, pushes water by a membrane that filters out the salt and is dear and energy-intensive. In contrast, the battery technique makes use of electrical energy to attract charged salt ions out of the water. Nonetheless, it additionally requires vitality to assist push the water by electrodes that comprise tiny, nonuniform pore areas.

“Traditional electrodes still require energy to pump fluids through because they do not contain any inherently structured flow channels,” stated College of Illinois Urbana-Champaign mechanical science and engineering professor Kyle Smith, who led the research. “However, by creating channels within the electrodes, the technique could require less energy to push the water through and eventually become more efficient than what is commonly used in the reverse-osmosis process.”

Smith’s battery-based desalination method builds from years of modeling and experiments by his analysis group at Illinois, culminating in a recent study demonstrating the primary use of electrodes containing tiny microchannels known as interdigitated circulation fields.

The group’s new research additionally incorporates IDFFs in electrodes, however this time the channel form is tapered, not straight. Utilizing electrodes with tapered channels improved fluid flow—or permeability —two to a few instances over straight channels. These findings are published within the journal Electrochemistry Acta.

“Our initial work on straight channels in electrodes led us to discover dead zones within the electrodes where we saw pressure drops and nonuniform flow distribution,” stated Illinois graduate pupil Habib Rahman. “To overcome this challenge, we created a library of 28 different straight channels to experiment with and understand conductance and flow variation, and eventually implemented this channel-tapering technique.”

Whereas performing the experiments, Smith and Rahman stated they confronted some manufacturing challenges, significantly with the time it takes to mill the channels into the electrodes, which might be problematic in any scaled-up manufacturing situation. Nevertheless, Smith stated they’re assured this problem may be overcome.

“Beyond its impact toward electrochemical desalination, our channel-tapering theory and associated design principles can be applied directly to any other electrochemical device that uses flowing fluids, including those for energy storage conversion and environmental sustainability like fuel cells, electrolysis cells, flow batteries, carbon capture devices and lithium recovery devices,” Smith stated.

“Unlike prior channel-tapering strategies that used impromptu designs, our approach here provides physics-based design guidelines to create uniform flow and minimize pressure drops simultaneously.”