|Home||» Products||» EDI / Electrodeionization Process Plant||» EDI (ELECTRODEIONIZATION) Plant|
What is Electrode ionization (EDI)?
EDI is a process which combines semi-impermeable membranetechnology with ion - exchange media to provide a high efficiencydemoralization process. Electrodialysis employ electrical current and specially - prepared membranes which aresemi permeable to ions based on their charge, electrical current, and abilityto reduce the ions based to their charge.
Electro dialysis an electrical potential transports and segregatescharged aqueous species. The electrical current is used to continuouslyregenerate the resin, eliminating the need for periodical regeneration.
The EDI process produces industrial process water of very highpurity, using less than 95% of the chemical products used in the conventionalion exchange processes.
Why to choose us?
EFPL offersa wide range of sizes, materials of construction and configurations to meet allof your EDI water needs. They can be ordered either as a stand-alone unit orintegrated into the most complex of de-ionized water control systems. EDIbrings advances in both energy and operating expenses to the high purity watertreatment train.
An EDI stack has the basic structure of a deionization chamber.The chamber contains an ion
Exchange resin, packed between a cationic exchange membrane and ananionic exchange membrane.
Only the ions can pass through the membrane, the water is blocked.When flow enters the resin filled diluting compartment, several processes areset in motion. Strong ions are scavenged out of the feed stream by the mixedbed resins. Under the influence of the strong direct current field appliedacross the stack of components, charged ions are pulled off the resin and drawntowards the respective, oppositely - charged electrodes. In this way thesecharged strong -ion species are continuously removed and transferred in to theadjacent concentrating compartments. As the ions go towards the membrane, theycan pass through the concentration chamber (see figure) but they cannot reachthe electrode. They are blocked by the contiguous membrane that contains aresin with the same charge.
As the strong ions are removed from the process stream, theconductivity of the stream becomes quite low. The strong, applied electricalpotential splits water at the surface of the resin beads, producing hydrogenand hydroxyl ions. These act as continuous regenerating agents of the ion -exchange resin. These regenerated resins allow ionization of neutral or weakly- ionized aqueous species such as carbon dioxide or silica. Ionization isfollowed by removal through the direct current and the ion exchange membranes.