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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In this compartment the pH becomes acidic, and O2 gas and a small amount of Cl2 dissolved are generated. High purity deionized water electrodeoinization. Anion-selective membranes are permeable to anions but not to cations; cation-selective membranes are permeable to cations but not to anions. Our high-quality modules continually produce ultrapure water up to EDI is just as sensitive to the chlorine as thin-film reverse osmosis RO processes.
This article relies too much on references to primary sources. Strong ions are scavenged out of the feed stream by the mixed bed resins. May be registered in one or more countries. These systems typically use cation exchange vessels followed by anion exchange to handle the bulk of the demineralization.
Leaks have been completely eliminated in some modern module designs. An anode is setup on the left side of the setup and a cathode is setup on the right side of the setup. Service Mixed Bed Deionization off-site regenerated rental vessels.
Electrodeionization – Wikipedia
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. EDI may be considered to be a competitive alternate process to: State-of-the-art water treatment systems utilize reverse osmosis RO membranes to do the bulk of the demineralization.
Ion-selective membranes operate using the same principle and materials as ionexchange resins, and they are used to transport specific ions away from their counterions. As a substitute for the more traditional ion-exchange process, EDI brings advances in both energy and operating expenses to the high purity water treatment train. Views Read Edit View history.
There are also EDI units that are often referred to as continuous electrodeionization CEDI since the electric current regenerates the resin mass continuously. Aqueous two-phase system Azeotrope Eutectic.
The resins operate in steady state; they act not as an ion reservoir but as an ion conduit. It differs from other water purification technologies in that it is done without the use of chemical treatments and is usually a polishing treatment to reverse osmosis RO.
The ion exchange beds in our EDI systems are regenerated continuously so that they do not exhaust in the same way as ion exchange beds that are operated in batch mode.
Some of the advantages of the EDI as opposed to the conventional systems of ionic interchange are:. Ions in the separate chamber are flushed to waste. Electrodeionization is a water treatment technology that utilizes electricity, ion exchange membranes and resin to deionize water and separate dissolved ions impurities from water. Most EDI devices have a 1 ppm hardness limit which is easily addressed with proper pretreatment system design. Any ionic species formed from the carbon dioxide gas will lower the outlet resistivity of the water produced by EDI.
Duplexing of large EDI systems is not required, because a single EDI module may be taken off line for maintenance or repair while the remaining modules operate at a slight increase in flow rate to maintain the required flow through the system. In this compartment the pH becomes neutral, and H2 gas is generated.
Each cell consists of an electrode and an electrolyte with ions that undergo either oxidation or reduction. When flow enters the resin filled diluiting compartment, several processes are set in motion.
Removal Mechanisms While both ion exchange and EDI use ion exchange resins, the removal mechanisms are quite different.
Electrodeionization (EDI) – Lenntech
RO systems do not require chemical regeneration and also remove many types of electrodeionizaton organic carbon TOC which will pass through ion exchange resins. The management of CO 2 in water is typically handled in one or two ways: Introduction to EDI gives you the basics. No ion exchange process is cost-effective for removal of large amounts of CO electrodionization.
Recently, Argonne National Laboratory developed a process called Resin-Wafer Electrodeionization RW-EDIwhich uses a unique porous resin wafer mold made from immobilized loose ion-exchange resin beads. RW-EDI is a process that targets the desalination of impaired water or water with salt levels of 1, – 10, ppm.
Located in a severely water scarce area in Tarragona, our customer, Gas Natural, needed to convert seawater into ultrapure water for power production. These act as continuous regenerating agents of the ion-exchange resin. The reject stream is usually of better quality than the feed to porcess RO system, enabling the reject stream to be completely re-used by pumping it back to the pretreatment section of the RO system.
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Each electrode may become either the anode or the cathode depending on the voltage applied to the cell. Ion-selective membranes allow the positive ions to separate from the water toward the negative electrode and the negative ions toward the positive electrode. Always run at least 5 litres of purified water to drain after a period of inactivity, e. Water Treatment – Old vs. Sensitivity to hardness Most EDI devices have a 1 ppm hardness limit which is easily addressed with proper pretreatment system design.
An electrolyte is a substance containing free ions that behaves as an electrically conductive medium. Welcome to Introduction to EDI.
EDI is used with reverse osmosis to replace ion exchange resin-mixed beds, which require onsite or offsite chemical regeneration. Retrieved from ” https: We’re here to help. Because they generally consist of ions in solution, electrolytes are also known as ionic solutions, but molten electrolytes and solid electrolytes are also possible.
Water enters the EDI module, where an applied current forces ions to move electrodeionziation the resins and across the membranes.