A team at the Massachusetts Institute of Technology (MIT) has come up with an innovative approach that, unlike most traditional desalination systems, does not separate ions or water molecules with filters, which can become clogged, or boiling, which consumes great amounts of energy.

Instead, the MIT-developed system uses an electrically driven shockwave within a stream of flowing water, which pushes salty water to one side of the flow and fresh water to the other, allowing easy separation of the two streams.

In the new process, called shock electrodialysis, water flows through a porous material — in this case, made of tiny glass particles, called a frit — with membranes or electrodes sandwiching the porous material on each side. When an electric current flows through the system, the salty water divides into regions where the salt concentration is either depleted or enriched. When that current is increased to a certain point, 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 center of the flow.

Researchers say the new desalination method could be useful for cleaning the contaminated water generated by hydraulic fracturing, or fracking.


Also: Learn about Rotating Reverse-Osmosis for Water Purification.