ELECTRODEIONIZATION PROCESS PDF
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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Each cell consists of an electrode and an electrolyte with ions that undergo either oxidation or reduction. In some cases, the ion exchange resins actually contribute to the TOC content in the water.
Eliminates expensive and hazardous chemicals used in ion-exchange resin regeneration Reduces energy and operating expenses Reduces the facility size requirement Helps plants meet ISO requirements.
The EDI process is a continuous process, utilizes no chemicals for regeneration, does not pollute the environment and requires a fraction of the operator attention necessary for conventional ion exchange systems. A bipolar electrode is an electrode that functions as the anode of one cell and the cathode of another cell.
Aqueous two-phase system Azeotrope Eutectic. 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.
What is Electrodeionisation or EDI
The main applications of EDI technology, such as that supplied by Ionpure, E-cell and SnowPure, are in electronics, pharmaceuticals and power generation. The chamber contains a ion exchange resin, packed prodess a cationic exchange membrane and a anionic exchange membrane.
State-of-the-art water treatment systems utilize reverse osmosis RO membranes to do the bulk of the demineralization. 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. The polishing of the RO elevtrodeionization water is carried out by continuous electrodeionization EDI which is capable of producing water in excess of 18 megohm resistivity.
Because of this, EDI: How does it work?
The combination of ion-exchange resins and ion-exchange membranes, which are used to move ionic impurities into a waste or concentrate water stream leaving purified product water. When fed with low TDS feed e. Simple and continuous operation Chemicals for regeneration completely eliminated Cost effective operation and maintenance Low power consumption Non pollution, safety and reliablility It requires very few automatic valves or complex control sequences that need supervision by an operator It requires little space It produces high pure water in a constant flow It provides complete removal of dissolved inorganic particles In combination with reverse osmosis pre-treatment, it removes more than While both ion exchange and EDI use ion exchange resins, the removal mechanisms are quite different.
RW-EDI process uses a porous ion exchange resin wafer with cm2 cross-section surface area. You may also be interested in These act as continuous regenerating agents of electrodeionizatuon ion-exchange resin. In this compartment the pH becomes acidic, and O2 gas and a electrodeionizahion amount of Cl2 dissolved are generated.
A single EDI unit may operate for many years before a replacement is required. Sensitivity to hardness Most EDI devices have a 1 ppm hardness limit which is easily addressed with proper pretreatment system design. It will also better prepare you for the content in the Intermediate EDI section. The electrolyte stream flows past the anode and cathode sequentially.
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Located in a severely water scarce area in Tarragona, our customer, Gas Natural, needed to convert seawater into ultrapure water for power production. EDI provides a high quality electrodeiojization, low in particles, partiall due to the fact that there is no resin attrition from backwashing or osmotic shock, as would electordeionization the case with conventional ion exchange electrodeionizatipn.
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. Electrldeionization the ions go towards the membrane, they can pass through the concentration chamber see figure but they cannot reach the electrode. EDI is just as sensitive to the chlorine as thin-film reverse osmosis RO processes.
Leaks have been completely eliminated in some modern module designs. Only the ions can pass through the membrane, the water is blocked. Thus, the waste stream expels the unwanted chlorine, oxygen, and hydrogen gas from the electrodes. In this compartment the pH becomes neutral, and H2 gas is generated. With EDI system membranes and electricity replace the million gallons of acid and caustic chemicals that the old processes required daily.
The electrical current is used to continuously regenerate the resin, eliminating the need for periodical regeneration. The resins operate in steady state; they act not as an ion reservoir but as electrpdeionization ion conduit.
Ions in the separate chamber are flushed to waste. EDI utilizes chemical-free regeneration.