Water Desalination and Purification Using Ion Concentration Polarization Method
Dr. Hamed Salimi Kenari
Water desalination is an important approach for drinking water limitations. Membrane processes (such as reverse osmosis) are widely used for seawater desalination, but require expensive water purification and delivery infrastructures. In addition the membrane is prone to fouling, and heavy metal rejection rates could decrease over time. One of the emerging methods to compensate for these disadvantages is the desalination of water based on the polarity of ion concentration. This study elucidates a noveldesalination/purification process, where a continuous contaminated stream is divided into filtered and concentratedstream by the ion concentration polarization (ICP). The virtual barrier for ion repulsion is formed by applying a voltage across the membrane. The applied voltage cause to accumulate of positive ions behind the membrane comes into the chamber, then lead to form an ion depletion zone. In this way; the salt-containing current flows out of both sides of the membrane and the salt-free current will pass through the membrane. The shape and geometry of the system, the intensity of the incoming water flow are important in the formation of the ion depletion zone.Therefore, an ICP implementation as described,significantly reduces the possibility of membrane fouling and salt accumulation, thusavoiding two problems that plague other membrane filtration methods. The energy and removal efficiency, and low cost manufacturability hold strong promises for portableself-powered water purification/desalination system thatcan have significant impacts on water shortage indeveloping/rural part of the world.