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How Does a Deionization System Work?

Water deionization is a vital step in the water purification process of multiple industries. Modern technological advancements in production processes require increasing levels of purity. A deionization system assists by removing and replacing sodium ions with hydrogen ions, resulting in ion-free water, fit for use in high-tech production or for the next step in a comprehensive water purification system.

What Is the Purpose of the Process?

Deionized water is used in a number of industries, including food and beverage production, auto body finishing, hospital systems, pharmaceutical production, textile and chemical plants and more. Deionization is normally only one component of a larger water purification process and is considered a polishing technique. It is not designed to trap and extract organic matter, bacteria or other unwanted particles. If it does succeed in purifying these substances, it most likely occurs through an accidental, circumstantial trapping of the materials in the resin exchange material.

Two-Step Deionization Process

For removal of all salt, the water must pass through two different ion exchange materials. The first phase of the process involves the exchange of metallic ions then present in the water, such as calcium and magnesium, for hydrogen ions. This is the basis of a water-softening process as well, but in the first phase of deionization, all metallic ions are removed, rather than only calcium and magnesium. After passing through the first material exchange, the supply loses all sodium ions and they are replaced with hydrogen ions. The resulting fluid is positively charged with a high number of hydrogen ions and is then ready to complete the next stage of the process.

The second exchange material involves displacement of current negative ions, referred to as anions. All anions in the water supply are replaced with hydroxyl anions. Through chemical processes, the negative hydroxyl bonds with the positive hydrogen to create water, eliminating all presence of ions in the water.

Types of Deionization Systems

Bed deionization systems are either separate or mixed. Separate systems direct the water through one resin bed at a time. Mixed-bed systems conduct ion exchanges simultaneously. Both types require a recharging of the resin exchange material after a certain amount of water has been processed.

While both separate and mixed bed deionization systems exist, electrodeionization utilizes an electric field and reverse osmosis to achieve the same results, without needing to replenish the exchange material. The ions are transported through the system and removed, allowing for constant processing with no pause for system maintenance. A continuous electrodeionization system’s life span can extend over five years, depending on the industry and the size of the system. Other options include capacitative electrodeionization systems, in which the supply is processed in batches. 

Contact Innovative Water Treatment ​for the design, production and installation of a specialized water deionization system to fit the needs of your industry.

1 Comment

Don - January 28th, 2016 at 4:22am

Excellent article. Water Deionization helps keep things clean and working well. Although at Waterline Controls our sensors are corrosion free, the rest of most systems are not. Properly maintaining the quality of the water is paramount in preventing buildup and damage to HVAC cooling tower systems.