Researchers in US develop new desalination method using shockwave

Researchers at Massachusetts Institute of Technology (MIT) in the US have developed a new desalination method that uses an electrically driven shockwave to separate salt from water.

The shockwave within a stream of flowing water pushes ions in the salty water and fresh water apart and does not separate ions or water molecules with filters unlike traditional desalination systems.

The new method, called shock electrodialysis, allows water to flow through a porous material made of tiny glass particles, called a frit. The porous material is squeezed between membranes or electrodes.

An electric current is applied to the system to divide salty water into regions where the salt concentration is either depleted or enriched.

When the current is further increased, it generates a shockwave between these two zones, sharply dividing the streams and allowing the fresh and salty regions to be separated by a simple physical barrier at the centre of the flow.

MIT chemical engineering and mathematics professor Martin Bazant said that even though the new system can use membranes on each side of the porous material, the water flows across those membranes, not through them which means they are not as vulnerable to fouling or to degradation due to water pressure, as happens with conventional membrane-based desalination, including conventional electrodialysis.

The research was backed by the MIT Energy Initiative, Weatherford International, the USA-Israel Binational Science Foundation, and the SUTD-MIT Graduate Fellows Program.

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Image: Researchers say the new desalination method could be useful for cleaning the contaminated water generated by hydraulic fracturing, or fracking. Photo: courtesy of Massachusetts Institute of Technology.