Researchers reveal shockwave desalination technique

BOSTON, Nov. 12 (UPI) -- Researchers at MIT have developed a new desalination technique using an electric shockwave.

The new process does not require the use of membrane filters, which can become clogged and degraded over time. Nor does it require water to be boiled, an energy-intensive process.

Traditional desalination technologies, including reverse osmosis and electrodialysis, require barriers to separate out salt's larger sodium and chlorine atoms. The new technique coaxes water to separate on its own, divided by an electric shockwave.

"The salt doesn't have to push through something," Martin Bazant, professor of chemical engineering and mathematics at MIT, explained in a press release. Instead, the ions "just move to one side."

Bazant is the lead author of a new paper on the process, published this week in the journal Environmental Science & Technology Letters.

The new technology is rather simple. First, the water is guided through a porous material, a "frit" composed of tiny glass particles. The frit is sandwiched by electrodes, or current-carrying membranes. When the current is switched on, the flowing water begins to divide into two columns, one more salty and one less salty.

As the electricity is revved up, a shockwave is generated between the two columns and the salt and non-salt water molecules separate entirely. A simple barrier can be used to divide the two columns from each other.

"It generates a very strong gradient," Bazant said.

Though the technology may eventually be scaled up, as of now, its not ready to compete with larger reverse osmosis and electrodialysis. But the less complex -- downsized and cheaper -- setup make it ideal for emergency use, like in the wake of a water quality-compromising storm, or in remote locations.

It could also be used to clean and desalinize waste water generated by fracking. Right now, fracking operators struggle to find safe and effective places to store wastewater.

"The electric fields are pretty high, so we may be able to kill the bacteria," said graduate student Sven Schlumpberger, one of the paper's co-authors.