물 증류공정에 사용되는 배터리가 기존의 전통적인 RO 담수화와 비교해 더욱 효율적일 뿐만 아니라 여러 장점을 가지고 있다는 연구결과가 발표됐다. 일리노이 공과대학교 Kyle Smith 교수와 대학원생 Rylan Dmello는 『미국전기화학회지(Journal of the Electrochemical Society)』에 이와 같은 연구내용을 실었다.

연구진은 소금물을 포함하는 나트륨 이온 배터리에 영감을 받았다고 전했다. 배터리는 양극과 음극 두 개의 챔버로 구성되어 있다. 배터리가 방전될 때 소금의 두 구성물질인 나트륨과 염화물 이온은 한 챔버로 빼져나가고, 다른 한 쪽에는 담수화 된 물이 남게 되는 원리이다.

 

 

 

A battery inspired water distillation process could be more efficient and hold several advantages compared to traditional reverse osmosis (RO) desalination, researchers have claimed.

 

The University of Illinois mechanical science and engineering professor Kyle Smith and graduate student Rylan Dmello published their work in the Journal of the Electrochemical Society.

 

Researchers were inspired by sodium ion batteries, which contain salt water. Batteries have two chambers, a positive electrode and a negative electrode, with a separator in between that the ions can flow across.

 

When the battery discharges, the sodium and chloride ions - the two elements of salt - are drawn to one chamber, leaving desalinated water in the other.

 

In a normal battery, the ions diffuse back when the current flows the other direction. The Illinois researchers looked to find a way to keep the salt out of the now-pure water.

 

The battery method uses electricity to draw charged salt ions out of the water.

 

According to the researchers, the method could hold several advantages over RO membrane processes.

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's 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.

 

Smith and Dmello conducted a modeling study to see how their device might perform with salt concentrations as high as seawater, and found that it could recover an estimated 80% of desalinated water. Their simulations don't account for other contaminants in the water, however, so they are working toward running experiments with real seawater.

 

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 university said.

 

Smith said: "In a conventional battery, the separator allows salt to diffuse from the positive electrode into the negative electrode. That limits how much salt depletion can occur. We put a membrane that blocks sodium between the two electrodes, so we could keep it out of the side that's desalinated."

 

[출처 = Water World / 2016년 2월 15일]