De-Ionized Water: Duration, Storage, and Ionization Factors Explained"

[banerjeerupak]

Hi,

How long does de-ionized water remain de-ionized. After what amount of time would it start geting ionized again. I understand that it would greatly depend on the container in which it is kept and the environmental conditions. However, the order of the time would help me.

Thanks.

 

[Bloodthunder]

Deionized water, also known as demineralized water[2] (DI water, DIW or de-ionized water), is water that has had its mineral ions removed, such as cations from sodium, calcium, iron, copper and anions such as chloride and bromide. Deionization is a physical process which uses specially-manufactured ion exchange resins which bind to and filter out the mineral salts from water. Because the majority of water impurities are dissolved salts, deionization produces a high purity water that is generally similar to distilled water, and this process is quick and without scale buildup. However, deionization does not significantly remove uncharged organic molecules, viruses or bacteria, except by incidental trapping in the resin. Specially made strong base anion resins can remove Gram-negative bacteria. Deionization can be done continuously and inexpensively using electrodeionization.

Deionization does not remove the hydroxide or hydronium ions from water. These are the products of the self-ionization of water to equilibrium and therefore are impossible to remove.

http://en.m.wikipedia.org/wiki/Purified_water

So as long as you keep the water sealed and all that, your water is kept clean. No "order of time" or whatever.

 

[Mapes]

So as long as you keep the water sealed and all that, your water is kept clean.

No, the deionized water will immediately begin dissolving the container in which it is sealed. To see how fast this occurs, measure the water's resistivity as it falls from a maximum of about 18 MΩ-cm.

 

[Bloodthunder]

isn't DI water usually kept in glass bottles?

 

[Mapes]

isn't DI water usually kept in glass bottles?

Not in my lab. I don't want all the components of soda-lime glass in my DI water!

 

[banerjeerupak]

Thanks for the insight. The replies have all helped a lot. I understand that it is highly pure form of water. And it is quite corrosive too due to the attraction it shows to ions in whichever container it is kept in. I am keeping my DI water in plastic containers. I was hoping for a time scale such as "it no longer remains essentially DI after about a week". But this question has improved my understanding off the DI water

 

[Bloodthunder]

In mine it's kept in glass bottles (or more appropriately, a gigantic glass vat). And it doesn't dissolve glass anyway. I think. Haven't yet checked, hmm... =P

 

[Borek]

In mine it's kept in glass bottles (or more appropriately, a gigantic glass vat). And it doesn't dissolve glass anyway.

Be sure it does. Keeping water at 18 MΩcm is not an easy task.