Purified water is necessary for many different companies, including those in the cosmetics, food and beverage, power, pharmaceutical, and microelectronics sectors, among others. An important factor in achieving consistency in production and equipment performance, is thus the use of purified feed water and process streams.
You may still be unsure of the distinctions between deionized (DI) and EDI water, despite the fact that it is simple to understand. This article provides an overview of the fundamental difference between deionization and electrodeionization, and the advantages of EDI system.
What is de-ionization?
The removal of ions is known as deionization. It may be commonly referred to as "DI Water" or "Demineralization." Ions are positively or negatively charged, and electrically charged atoms or molecules are found in water. These ions are regarded as contaminants and must be eliminated from the water in many applications, where water is used as a rinse or component.
Cations and Anions are the corresponding positive and negative charged ions, respectively. Ion exchange resins are used to convert unfavourable cations and anions into hydrogen and hydroxyl, respectively, in order to produce clean water (H20).
The ions that are typically present in municipal water are listed below:
Cations which are removed by cation resins |
Anions which are removed by anion resins |
Calcium (Ca++) |
Chlorides (Cl-) |
Magnesium (Mg++) |
Sulphates (SO4--) |
Iron (Fe+++) |
Nitrates (NO3-) |
Manganese (Mn++) |
Carbonates (CO3--) |
Sodium (Na+) |
Silica (SiO2-) |
Hydrogen (H+) |
Hydroxyl (OH-) |
What is a deionized water treatment system?
A deionized water treatment system is a configuration of DI tanks and additional parts used to provide ultra-pure water. The DI tanks normally come in a variety of sizes to handle varied feed flow rates and are made of fibreglass. A deionized water treatment system can be as straightforward as a single tank configuration, or as sophisticated as a multi-tank design with auxiliary equipment including reverse osmosis, ultraviolet (UV) disinfection, and elaborate water quality monitoring apparatus. Ion exchange resin is found in DI tanks, which selectively removes ions from water.
For an on-going supply of deionized water, many clients want standby DI tanks on-site. The quantity and quality of incoming water as well as water usage, determines how frequently the DI tank needs to be exchanged. Less gallons of water will be produced by the DI tank as a result of the greater ionic load, in the entering feed water.
RO + DI water treatment system
To reliably create high-quality deionized water, a reverse osmosis system can be utilised in conjunction with DI. 90% to 99% of the dissolved solids will be removed by the RO Plant before the water enters the DI tank, which will then remove any ions that are still present.
You may get a significantly longer run time from your DI tanks and save money by placing a RO before them. When selecting a DI system, one must keep in mind that a RO system necessitates a significantly higher upfront investment, on-going maintenance, and the capacity to release brine waste from the RO unit.
What is electrodeionization?
Ion exchange membranes, electricity, and resin are all used in the electrodeionization (EDI) process, to remove ionised species from water.
What is eliminated from water during electrodeionization?
Ions and other charged species, such as salts and organic acids, are removed from water by EDI.
What happens during electrodeionization? How does EDI operate?
The EDI module is made up of a number of chambers connected by ion-exchange membranes, and containing ion exchange resins. Water enters the module where it is forced to move across the membranes, and through the resins by an applied electrical field that is applied at a right angle to the flow. Instead of being permanently attached to the media, these impurity ions are gathered into concentrate streams that can be sent down the drain or recycled. You can use the deionized product water right away or you can further treat it to make it more pure.
The EDI module functions, in essence, as a continuously electrically recharged ion exchange bed. Ions are converted into H+ and OH- ions as they pass through resins and between cation or anion selective membranes. Under the influence of the externally provided electric field, ions that bind to the ion exchange resins eventually migrate to a different chamber, producing the H+ and OH- ions required to keep the resins in their regenerated condition. Ions in the distinct chamber are disposed of.
What is the difference between the DI and EDI water treatment system?
Deionization (DI) is an important step in obtaining high-purity water quality. The primary method of treating DI has long been ion exchange (IX), which has existed in a variety of configurations since its invention in the 1940s. These configurations include separate anion and cation beds, mixed beds, polishing beds, and packed beds, among others. High-purity water systems have developed over time, with supplementary treatment stages made to operate with IX.
Electrodeionization (EDI), a different DI treatment method, first appeared in the 1980s. Early systems had modest capacity that were useful for purifying water for laboratories, but over time, makers of EDI systems have created machinery that can generate the volumes of purified water, required for a power plant or other industrial end users.
Additionally, in order to assure optimal performance, water system designers have identified the required pretreatment stages, specifically the usage of reverse osmosis before EDI. The fact that EDI does not require chemical regeneration is one of its advantages, which is a desirable quality.
What are the advantages of EDI systems?
Firstly, in contrast to ion exchange beds that are used in batch mode, the ion exchange beds in EDI systems are continually regenerated to prevent exhaustion. The concentrates used to eliminate the impurities prevent them from accumulating and wearing down the resin. It may be many years before an EDI unit needs to be replaced.
Secondly, this method yields products with water resistivity’s of >15 M.cm. The usage of this technology can replace single-use purification cartridges. Avoiding replacing cartridges has several advantages, including reduced downtime and practical benefits.
Finally, compared to single-bed ion-exchange systems, which could liberate weakly bound ions when the media exhausts, EDI can also give more consistent purity. Additionally, the release of organic contaminants is decreased, by the reduced resin quantities in an EDI module as compared to an ion-exchange bed.
High quality water treatment plants from Netsol
Clean water is produced by Netsol Water water treatment systems, which are designed, built, and installed with safety and the environment in mind. Our EDI units can be constructed according to the needs of the customer.
Our systems have been certified. We also encourage our clients to talk to us about the high-quality, pure water they need. Our technical staff is also able to precisely design and build the device, with great quality criteria. Call us at +91 9650608473 or email at enquiry@netsolwater.com for further information.