Radial deionization – RDI™
Radial deionization – RDI™ – is a proprietary form of capacitive deionization (CDI). In radial deionization, an aqueous stream containing salt is passed between two oppositely charged supercapacitors. As the liquid passes through the dielectric spacer separating the capacitors, ions are attracted to the oppositely-charged capacitor layers. The ions leave the water within the dielectric layer, pass through a charge specific membrane coating, and are adsorbed onto the surface area of the carbon supercapacitor. When the capacitors have filled with ions, the polarity is reversed and the ions are discharged back into the dielectric spacer and removed from the system. A 3-way valve is situated at the outlet of the device(s), directing brine away from the cleaned water.
RDI™ differs significantly from previous generations of capacitive deionization in a number of keys areas. First, the supercapacitor design allows for water to flow across 1 – 10 meters of continuous supercapacitor material. The current state-of-the-art CDI only allows for flow across 10 cm of material, or 1/100th of the distance. The long distance allows for greater total dissolved solids (TDS) reduction and for processing of very high TDS streams and flow rates. The RDI™ Desalination System also incorporates proprietary operating techniques that enable fouling resistance, energy conservation, brine concentration, and backwashing. The RDI™ Desalination System’s supercapacitors also incorporate the latest generation materials, allowing for extremely high capacity for salts.