Scientists report low energy, non-membrane desalination technique

A team of American and German researchers have reported an electrochemical method for desalination of seawater that uses no membranes and which they claim consumes only a small amount of energy.

The system developed by Richard Crooks of the University of Texas at Austin and Professor Ulrich Tallarek of the University of Marburg uses electrolysis to create an ion imbalance between two microchannels that draws other ions through one channel leaving desalinated water in the other channel.
The researchers claim the energy required for the technique is so low that it can operate with a simple battery. Sand and sediment needs to be removed from the seawater but disinfection or pre-treatments are not needed. The researchers anticipate that a parallel arrangement of many microchannels will generate the required water throughput for commercial use.
The channels are about 22 µm wide. An auxiliary channel and a branched working channel, each flow to the outlet and are electrically connected to each other and a power source. The channels and electrode are arranged so that chorine is released from the seawater by electrolysis to create a zone of excess positive ions. The electric field gradient then directs salts and desalinated water along separate channels.
The research was supported by the American Department of Energy.