Where the
world gathers for metal finishing
Q&As since 1989


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De-ionised water

I have to perform a test with either demineralised or distilled water added to fuel. However I have a stock of de-ionised water, could I use this instead? What is the main difference between all 3 types of water?

Kevin Platt
filters - England
2002

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You can use deionized in place of demineralized; they are the same. The difference between deionized and distilled is that if you don't carbon filter in the deionization process you may have organics present.

James Totter, CEF
- Tallahassee, Florida
2002

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De-ionised water has been processed by ion exchange to remove most of the contaminating ions. Demineralised water is the same thing. Distilled water has been boiled and condensed, so it only has water in it and perhaps some dissolved gases; the more times you distill it, the purer it becomes. Reverse osmosis water is water that has been squeezed through a very fine membrane that only allows the water molecules through and leaves the contaminating other ones on the "dirty" side of the membrane.

You need to be careful of all "pure" water, as it is a luxury hotel for bugs, so it is a good idea to have a UV light treatment built into the system

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2002

I bought a 'High Purity Silver Colloid' and listed as specifications it says: "Made from sub-micron filtered, degassed and de-ionised water." I understand de-ionised could mean either water that has been passed through ion-exchange or distilled, but how do you degassed water, at the same time keep the water at a degassed state so that colloidal silver can be made?

Pat Young
- Australia
2003

Could you please explain the difference between demineralised water and distilled water?do distilled water can be used inplace of demineralised water?

Vinesh
alfurat drinking water - UAE
2006

Please can you tell me how to make my own deionised water as I need it for my sons Christmas present.

David Tetley
nil - Northampton, Northants, England
2007