How to Store Deionized Water

Deionized water is ultra-pure water that has had all ions removed from it. It is used in many scientific and industrial applications, where the presence of ions may interfere with results. The removal of the ions from water makes it very corrosive, therefore proper and appropriate storage is required.



When an appropriate storage container has been selected, further precautions are required in order to preserve the ultra-pure status of the deionized water.

Storage

• 1

  Select the type of container to be used for the storage of the quantity of deionized water. Since deionized water is corrosive, only certain substances are suitable as the component of a storage container. If the container to be used is ceramic or made of metal, it will need to be lined with tin. Alternatively, glass is a good material for the storage of deionized water, as are certain plastics--although PVC is not suitable, as some chemicals present in PVC can leach into the water.

• 2

  Protect the deionized water once in a storage container from outside contaminants such as bacteria and microbes, which may enter from the air. This can be done by sealing the container tightly with a substance that will not react with the water. As deionized water is ultra-pure and must remain so for scientific experiments and industrial applications, preventing this contamination is essential.

  Ozonation is one way to prevent this contamination; this involves treating the water with ozone to remove any bacteria or microbes which may be present in it. Following this ozonation, the deionized water container can then be sealed to prevent any further contamination.

• 3

  Stabilize the pH of the deionized water to reduce its level of reactivity and conductivity. This can be done with the addition of a buffer to the water.

  pH changes can occur within deionized water fairly easily; one way that this can happen is that, in protecting the deionized water from the air and the potential microbes within it, the carbon dioxide within the air already present in the container can dissolve in the water. The dissolution of carbon dioxide in water will change the pH of the water. A buffer such as potassium permanganate will prevent this change in pH and the other property changes which may accompany it. Add a few drops of prepared buffer to the deionized water with a dropper.

• 4

  Empty the deionized container completely before refilling with freshly deionized water. This will help to maintain the pureness of the deionized water by preventing contamination by microbes.