Electro-deionization (EDI) is based on the engineering principle of electrodialysis.  It is an electrochemical separation process in which ions from a low concentration solution pass through a special membrane to a solution of higher concentration.  The activating force is an electric field between cathode and anode.
In this electric field, anions (ex. Cl-) pass through the anion exchange membrane on their way to the anode and the cations (ex. Na+) through the cation exchange membrane on their way to the cathode.  This results in a solution with low salt concentration (diluate) between the two membranes and a solution with high salt concentration (concentrate) outside of the ion exchange membranes.
 
Application:
Production of high purity and ultrapure water for industrial applications (chemical, cosmetic, pharmaceutical industries, semiconductor industry).  Alternative to mixed bed ion exchange plants.
 

Performance
Throughput from a few liters to many cubic meters per hour are possible, depending on the size of the EDI cells and the position of cells in relation to one another.  EDI technology can produce electric conductivities of 0.1 µS/cm and less.  The system works with a pure water yield factor of about 90-95% (the proportion of diluate to feed water).  The resulting concentrate is normally piped back to the pre-desalination stage, which minimizes waste water output.

• continuous process with constant quality standard
• no regenerative chemicals necessary
  low energy costs
• easy operation due to automation
• high product quality
• high product yield

Mr. Vassilios Toulikas
plants.engineering(at)envirochemie.com 
Phone +49 (0) 61 54 / 69 98 – 883