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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Anion-selective membranes are permeable to anions but not to cations; cation-selective membranes are permeable to cations but not to anions.
Some of the advantages of the EDI as opposed to the conventional systems of ionic interchange are:. Electrodeionization is a water treatment technology that utilizes electricity, ion exchange membranes and resin to deionize water and separate dissolved ions impurities from water.
EDI modules can be sized to operate from a fraction of a gpm up to about proocess gpm. EDI may be considered to be a competitive alternate process to: Home page Technical Electrodeionization. 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.
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. 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.
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. 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.
Electro dialysis employ electrical current and specially-prepared membranes which are semi permeable to ions based on their charge, electrical current, and ability to reduce the ions electrdoeionization to their charge. Water Treatment – Old vs.
Introduction to Electrodeionization
High purity deionized water results. Ions in the separate chamber are flushed to waste. EDI has a significantly smaller footprint than conventional ion exchange processes.
Reuse of residual water in food and beverages industry Chemical production Biotechnology Electronics Cosmetic Laboratories Pharmaceutical industry Boiler Feed Water Reduction of ionizable SiO 2 and TOC total organic carbon Since installation EDI units perform quite reliably, providing the customers with high purity production water for either power plant boiler feed or microchip rinse electroseionization.
Water is fed through the wafer, while electrodeioinzation electric current is applied to setup.
The electrical current is used to continuously regenerate the resin, eliminating the need for electroddeionization regeneration. This section is broken down into the following topics:. You may also be interested in Ions that become bound to the ion exchange resins migrate to a separate chamber under the influence of an externally applied electric field.
EDI is different from ED by using resins in the diluting chambers—the resins allow for more efficient migration of ions in very low pfocess water.
EDI has significantly lower operating costs than conventional ion exchange processes. Articles lacking reliable references from December All articles lacking reliable references.
A single EDI unit may operate for many years before a replacement is required.
Ion-selective membranes allow the positive ions to separate from the water toward the negative electrode and the negative ions toward the positive electrode.
Water enters the EDI module, where an applied current forces ions to move through the resins and across the membranes. 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 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.
Electrodeionization (EDI) | Water Purification Technology | ELGA LabWater
Most EDI devices have a 1 ppm hardness limit which is easily addressed with proper pretreatment system design. The anode is defined as the electrode at which electrons leave the cell and oxidation occurs, and the cathode as the electrode at which electrons enter the cell and reduction occurs. Leaks have been completely eliminated in some modern module designs.
The combination of ion-exchange resins and elecrodeionization membranes, which are used to move ionic impurities into a waste or concentrate water stream leaving purified product water.
Regenerable Mixed Bed Deionization No acid or caustic bulk storage, pumping, waste neutralization or disposal issues. In this compartment the proecss becomes neutral, and H2 gas is generated. These systems typically use cation exchange vessels followed by anion exchange to handle the bulk of the demineralization. CEDI technique can achieve very high purity, with conductivity below 0.
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. Since installation Electeodeionization units perform quite reliably, providing the customers with high purity production water for either power plant boiler feed or microchip rinse water. This article relies too much on references to primary sources.