What is deionized water?

Deionized water, also known as demineralized water, is water that has had the majority of its dissolved ions removed through a process called ion exchange. This process involves running the water through a resin bed that attracts and binds to the ions in the water. The most common ions removed are positively charged ions such as calcium, magnesium, and potassium, as well as negatively charged ions such as chloride and sulfate.

Deionized water is essentially pure H2O, with a very low level of total dissolved solids (TDS) or conductivity compared to the normal tap water. It can be used in a variety of applications where pure water is required such as in laboratories, industrial processes, and even in car radiators.

It is worth noting that while deionized water is considered to be pure, it may not be completely free of all contaminants, and can still contain small amounts of microorganisms or dissolved gases. Additionally, deionized water can absorb gases from the air and become more conductive over time. This is why deionized water is not recommended for drinking or cooking.

How does the resin in deionizer filters work?

Deionization (DI) filters use ion exchange resin to remove dissolved ions from water. There are two main types of ion exchange resin used in DI filters: cationic and anionic resins.

Cationic resin is a positively charged resin that is used to remove positively charged ions such as calcium and magnesium from the water. Cationic resin can be made from a variety of materials such as polystyrene or acrylics.

Anionic resin is a negatively charged resin that is used to remove negatively charged ions such as chloride and sulfate from the water. Anionic resin is typically made from styrene-divinylbenzene copolymer.

Both types of resins can be used in the same filter, typically arranged in a two-bed configuration: The first resin bed is cationic and the second is anionic to remove both positive and negative ions from the water.

DI filter systems also use a process called “regeneration” which is a process of cleaning the resin by flushing it with a strong acid or base. This process helps to remove the trapped ions and restore the resin's ability to exchange ions.

There are also other types of resin that can be used, such as chelating resin, which is able to remove metals ions and others specialized resin, but they are not as commonly used as cationic and anionic resin in typical Deionization filter.

How expensive is deionized water?

The cost of deionized water can vary depending on several factors such as the source of the water, the level of purification required, and the location. In general, deionized water is more expensive than tap water because of the added cost of the ion exchange resin and the process of deionization.

For small volumes of deionized water, such as what is needed for car washing, you may be able to purchase pre-packaged gallons of deionized water at a retail store. The cost for this can vary, but it can typically range from a few dollars to around $10 or more per gallon, depending on the store and location.

For larger volumes, such as what might be needed for industrial or laboratory use, the cost of deionized water will depend on the volume and frequency of water needed. The cost can range from a few cents to several dollars per gallon. The cost will also be affected by the cost of regenerating the ion exchange resin, labor cost, and the cost of disposing of the used resin.

In industrial scale, a common method to get DI water is to have a Deionization filter system, which is relatively expensive to set up with costs ranging from a few thousand to tens of thousands of dollars depending on the size and flowrate of the system. Additionally, the resin replacement and disposal costs, which need to be considered as well.

It is worth noting that although the cost can be relatively high, the use of deionized water can bring many benefits to some application and may be worth the cost for the end-users.

Why you should use deionized water for car washing:

Deionized water is considered good for car washing because it has many of the dissolved ions that can leave spots on the car removed. When the water evaporates, dissolved minerals are left behind and can cause hard water stains or spotting. Deionized water has a very low level of dissolved minerals, so it is less likely to leave water spots on the car after it dries.

Deionized water is also commonly used in car detailing and professional car washing, the pure nature of deionized water helps to reduce the potential for damage to sensitive electronic equipment in the car, and it can also help to remove dirt and grime more effectively than tap water, which can contain dissolved minerals that can leave behind streaks and stains.

Moreover, since deionized water does not have the mineral content that tap water does, it does not dry out surfaces as much. When you use tap water for car washing, it can dry out rubber and plastic parts, causing them to crack over time. So, it also helps to prolong the life of your car parts by avoiding contact with normal tap water.

It's important to note that while deionized water is good for preventing water spots, it is not a substitute for using a good car shampoo and proper car washing technique. Using a car shampoo specifically designed for washing the car and washing the car correctly is still necessary to remove dirt, grime and other contaminants from the car surface.

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