Many modern water purification methods rely on filters and chemicals that require regular replenishing or maintenance. However, with these methods unsuitable for people in areas with limited access to such materials, a promising new plasma-device-based approach has been found.
A new type of plasma generator that pulses voltage signals to ionize gas at atmospheric pressure and produce useful byproducts could be the answer to more cost-effective water purification methods.
Among the byproducts are hydroxyl radicals, which cause a cascade of reactions that lead to purer water samples, say the researchers from the University of Alabama who created the new method.
“We’re finding ways to speed up the purification process,” commented Ryan Gott, a doctoral candidate at UAH, in a statement. “In theory, if this technology can be developed in a real-world, practical system, it would be able to purify water at lower costs than current methods can,” Gott said.
Most plasma-based water purification approaches work through plasma’s ability to generate reactive free radicals, rendering many compounds in the water inert, according to the statement. The plasma and ensuing chemical reactions release energy and chemical species that can kill even tough microcystin bacteria.
Unlike more common, ozone-producing plasma purifiers, the new device relies on the production of hydroxyl radicals – a method designed to avoid some of the hurdles that have hampered ozone-based counterparts, such as high power consumption and challenges keeping excessive heat in check.
Using optical emission spectroscopy, the UAH researchers compared how different factors play a role in producing more hydroxyl radicals from their plasma device. Increasing voltage, appears to have the biggest effect on output, followed by increasing the frequency of the pulses, added the statement.
The device is currently limited to 10 kilovolts, but the researchers are hoping to see what higher voltage could mean in the future.
“The end goal is to develop something that can be mass-produced and distributed to places that need it the most,” concluded Gott.
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