Batteries Could Help Turn Seawater to Fresh Water: Report

"We are developing a device that will use the materials in batteries to take salt out of water with the smallest amount of energy that we can," said one of the researchers Kyle Smith, professor at University of Illinois at Urbana-Champaign in the US.

The study appeared in the Journal of the Electrochemical Society.

Interest in water desalination technology has risen as water needs have grown, particularly in drought-stricken areas. However, technical hurdles and the enormous amounts of energy required have prevented wide-scale implementation.

The most-used method, reverse osmosis, pushes water through a membrane that keeps out the salt, a costly and energy-intensive process. By contrast, the battery method uses electricity to draw charged salt ions out of the water, the study said.

The researchers were inspired by sodium ion batteries, which contain salt water, and they believe that the battery approach holds several advantages over reverse osmosis.

The battery device can be small or large, adapting to different applications, while reverse osmosis plants must be very large to be efficient and cost-effective, Smith said.

The pressure required to pump the water through is much less, since it is simply flowing the water over the electrodes instead of forcing it through a membrane.

This translates to much smaller energy needs, close to the very minimum required by nature, which in turn translates to lower costs.

In addition, the rate of water flowing through it can be adjusted more easily than other types of desalination technologies that require more complex plumbing, the study said.

The researchers conducted a modelling study to see how their device might perform with salt concentrations as high as seawater, and found that it could recover an estimated 80 percent of desalinated water.