• Green Synergy Engineering

Pre and Post Filter for Deionized (DI) Water

Deionized water, also known as DI water, or ultrapure water, is a type of purified water in which almost all of it's mineral ions have been removed. This includes cations such as sodium, calcium, iron, copper, and anions like sulfate and chloride. It is even purer than distilled water.


Difference between RO water and DO water

Reverse Osmosis (RO) and DI water is made using different physical reactions.


RO grade water is also known as Type III water, and is created by pushing contaminated or salt water through a semipermeable membrane to create pure water. This typically removes up to 99% of contaminants.


Read more about the difference between tap water and RO water, as well as the application of RO water in hydroponics here.



DI grade water is also known as Type I water. The process uses ion exchange resins to remove ionized salts from water by exchanging hydrogen (H+) and hydroxyl (OH-) ions for dissolved minerals, and then recombine to form water (H2O). Unlike RO, this process doesn't use a physical filter or membrane, so bacteria, viruses, and organics will not be captured. Therefore, the purity of the water before it is processed makes a difference.


Uses of DI water

  • Biotech and Pharmaceutical Industry: DI water is known as a true water blank because it assumes the chemistry of whatever product is added. For example, a chemist who is making saline solution needs to use water that meets the standard of "water for injection". When the saline formula is added to DI water, it creates a replica of the solution they need. Surgical instruments are also cleaned using DI water and disinfectants to ensure absolute sterility.

  • Semiconductor Industry: Since DI water doesn't contain any electrolytes, it is used in large volumes in the production of semiconductors. Read more about ultrapure filtration for semiconductors here.

  • Glass Manufacturer: DI water is used to rinse their completed products. Tap water would result in deposits like calcium, magnesium, or silica on the glass surface.

  • Others: DI water is the water of choice for many manufacturers as it allows them to avoid salt buildup on their machinery. It can be used in the production of cosmetics, F&B, and microelectronics. It can also be used to cool and lubricate machines.


Pre and post filters for DI water

Because the production of DI water begins with the use of unpurified water, DI water manufacturers often face the problem of machinery fouling which result in costly repairs, replacements, or down times. Therefore, using prefilters or post filters have proven to be more cost efficient for DI water manufacturers.


The WaterTEC™ Series Filter Cartridges are constructed of absolute rated, hydrophilic, asymmetric polyethersulfone membrane and polypropylene components, suitable for DI water prefilter and post filter. Download the data sheet here, or contact us for inquiries.


Green Synergy Engineering is the sole distributor of Graver Technology Liquid Process Filters in Malaysia. Contact us to find out more about our products and services.

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