Download scientific diagram | Electrodeionization process diagram from publication: Study on the influence of applied voltage and feed concentration on the. Introduction to continuous electrodeionization concepts. EDI may be considered to be a competitive alternate process to: Regenerable Mixed Bed. Discover electrodeionization (EDI) solutions from SUEZ which offer superior provide key advantages compared to traditional ion-exchange processes.
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Views Read Edit View history. It will also better prepare you for the content in the Intermediate EDI section.
High purity water production has traditionally used a combination of membrane separation and ion exchange processes. One important aspect in the water treatment application is that some types of EDI needs to have feed water that is free from CO2, as well as other dissolved gasses, since these put unnecessary strain on the EDI unit and will reduce performance.
Argonne National Electrodeionizatiom estimates that Unlike DI resin, EDI does not require shutdowns for replacing resin beds or for resin regeneration using chemicals. Each cell consists of an electrode and an electrolyte with ions that undergo either oxidation or reduction. As the strong ions are removed from the process stream, the conductivity of the stream becomes quite low.
They are ideal for multiple applications including: The deionized wlectrodeionization water can then be used directly or undergo further treatment for enhanced water purity. Converting seawater to high electodeionization water at Spain power plant Located in a severely water scarce area in Tarragona, our customer, Gas Natural, needed to convert seawater into ultrapure water for power eleectrodeionization.
The ion exchange beds in EDI systems are regenerated continuously, so they do not exhaust in the same way as ion exchange beds that are operated in batch mode. Aqueous two-phase system Azeotrope Eutectic.
Electrodeionization (EDI) – Lenntech
It also enables you to see the benefits of EDI, understand how to design an EDI system and watchouts during design and operation to maintain your system. There are also EDI units that are often referred to as continuous electrodeionization CEDI since the electric current regenerates the resin mass continuously. Each electrode may become either the anode or the cathode depending on the voltage applied to the cell.
The resins operate in steady state; they act not as an ion reservoir but as an ion conduit. EDI is different from ED by using resins in the diluting chambers—the resins allow for more efficient migration of ions in very low conductivity water. The reject stream is usually of better quality than the feed to the RO system, enabling the reject stream to be completely re-used by pumping it back to the pretreatment section of the RO system.
The strong, applied electrical potential splits water at the surface of the resin beads, producing hydrogen and hydroxyl ions. The chamber contains a ion exchange resin, packed between a cationic exchange membrane and a anionic exchange membrane. For more information, including technical papers, case studies, and product specs, explore the electrodeionization EDI resource page in the Document Library.
What is Electrodeionisation or EDI
Eliminates the need for a second bank of RO membranes and associated plumbing, pumping and control electrdeionization. An EDI stack has the basic structure of a deionization chamber.
High purity deionized water results. The ion exchange systems are usually supplied in duplicate, to allow one system to provide water while the other one is being regenerated.
Thus, the waste stream expels the unwanted chlorine, oxygen, and hydrogen gas from the electrodes.
While both ion exchange and EDI use ion exchange resins, the removal mechanisms are quite different. Applications EDI is useful for any application that requires constant and economic removal of water lrocess without using dangerous chemical.
orocess Second pass of RO Eliminates the need for a second bank of RO membranes and associated plumbing, pumping and control equipment. Strong ions are scavenged out of the feed stream by the mixed bed resins.
The positively charged ions flow toward the cathode and are rinsed out in the concentrate stream, and the negatively charged ions flow toward the anode and are rinsed out in another concentrate stream. Its development and use in water purification overcame some of the limitations of ion exchange resin beds, particularly the release of ions as the beds exhaust and the associated need to change or regenerate the resins.
Purified water flows out through the opposite side of the compartment. As impurities leave via the concentrate water system, their build-up does not exhaust the resin and therefore prolongs resin lifespan. Please improve this by adding secondary or tertiary sources.
This page was last edited on 10 Octoberat Articles lacking reliable references from December All articles lacking reliable references. Located in a severely water scarce area in Tarragona, our customer, Gas Natural, needed to convert seawater into ultrapure water for power production.
May be registered in one or more countries. How EDI electrodeiomization ionized species from water.
Ions that become bound to the ion exchange resins migrate to a separate chamber under the influence of an externally applied electric field. You may also be interested in An electrolyte is a substance containing free ions that behaves as an electrically conductive medium.
Leaks have been completely eliminated in some modern module designs. Ions in the separate chamber are flushed to waste. How does it work? Home page Technical Electrodeionization.