ELECTRODIALYSIS

Electrodialysis belongs to the group of membrane–based separation processes. By a membrane–based separation process we understand a process of separation of substances or chemical reactions that are caused by different membrane permeability for particular parts of a solution. The main advantage of membrane–based processes is feasibility of a substance separation without phase changes, usually at ambient temperature, and also the chance of automation and continuing of these processes.

Electrodialysis Principle

When the electrodialysis is running, the direct current field affects the flow of dissociated salt components in water solution in such a way that cations moving towards the cathode pass through the cation exchange membranes and cannot go through the anion exchange membranes, while the anions drawn to the anode pass through the anion exchange membrane but stop at the cation exchange membranes. Using the right combination of anion exchange and cation exchange membranes we can separate the ions in the inlet solution and create a desalted flow called diluate, and concentrated flow called concentrate. Electrodialysis takes place in electrodialyzer, i.e. an equipment comprising tightening boards with electrodes and a bundle consisting of ion exchange membranes and spacers.

Scheme of Ion Separation in Membrane Bundle

CM - cation exchange membrane, D - diluate chamber, e1,e2 - electrode chambers,
AM - anion exchange membrane, K - concentrate chamber

Goal of Elektrodialysis

To acquire a product out of one part of the solution (diluate or concentrate) only can be the goal of electrodialysis. But sometimes quality is required of both products, especially when treating waste water, e.g. diluate must comply with the regulations for releasing diluate into water, and concentrate has to be of properties useful for other treatment.

Advantages of Using Electrodialysis

• variability of ED system operation
• easy operation of ED equipment
• demineralization of biological solutions without affecting the quality and quality of proteins and hydrocarbons
• energetically advantageous separation without phase changes and additional chemicals

Examples of Possible ED Utilization

• pharmaceutical industry
  • purification of fermented solution, serums and vaccines
• chemical industry
  • separation of inorganic and organic solutions
  • purification of organic substances, e.g. amino acids
  • waste water treatment, recycling of chemical substances
• food industry
  • demineralization of milk whey
  • wine stabilization
  • desalination of fruit juices
• other uses
  • desalination and conservation of sea and brackish water and industrial waters
  • regeneration and recycling of galvanic baths
  • purification of salty mine waters

In the Field of Electrodialysis MEGA a.s. Offers

• laboratory, pilot plant and industrial ED units with reverse (EDR) or without
• task analysis, solution proposal and laboratory proof tests
• project completion
• pilot tests using our mobile units directly at customerś facility  
• delivery of technologies on "turnkey" basis
• warranty and post-warranty service