I called Prestone a while back about using DI water versus distilled water and the guy kinda did a "HUH"? Heres the dilemma, the people that provide the DI water tell me that the water is so pure that it looks for minerals to absorb into. Now I don't know if that is good or not. Will it help to remove corrision or will it eat at the metals?. I just figured that the DI water is used for making/diluted chemicals in a water treatment lab so it might be ok to dilute Prestone.
Deionized Water
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Kestas
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In its pure form, this is true. When antifreeze is added to it, this effect goes away and makes DI water a good choice for mixing coolant. That's what I use. We have it on tap in our shop.
Originally Posted By: Kestas
In its pure form, this is true. When antifreeze is added to it, this effect goes away and makes DI water a good choice for mixing coolant. That's what I use. We have it on tap in our shop.
Bingo. The second 3 drops of AF are added to DI water this non-problem goes away. Seems like this one has reached mythic proportions in some circles.
In its pure form, this is true. When antifreeze is added to it, this effect goes away and makes DI water a good choice for mixing coolant. That's what I use. We have it on tap in our shop.
Bingo. The second 3 drops of AF are added to DI water this non-problem goes away. Seems like this one has reached mythic proportions in some circles.
How do you de-ionize water? The hydrogen present are H+, free protons, and the hydronium?hydroxyl? are-, 2 extra electons, these are both ions right? ph7 means 10-7 free protons, a few but not zero. Distillation will remove otherwise present minerals, precursors to deposits among other things so that should help. If off-topic appologies, I am trying to reform.
Deionized water is used extensively in labs and is regular water put through reverse osmosis membranes. Chepaer in the long run than distilling.
High quality DI water is basically the same as distilled. A water softener is a form of ion exchange, where cations such as calcium, magnesium, etc are exchanged for sodium, whose salts are much more soluble so produces less scale. The same ion exchange resin used for softeners can be used to exchange hydrogen ions for the cations if it is regenerated with sulfuric acid instead of salt. I was responsible for a large DI unit (600 gpm) at a power plant and it produced water of extremely high quality. After passing through cation units, the water went through a vacuum degasifier to remove CO2, then through an anion unit (regenerated with sodium hydroxide), then though a mixed bed exchanger that removed traces of anions and cations.
Years ago Mercedes Benz used to recommend not using di water for cooling systems over concern for the affinity of di water to pick up oxygen, though I never understood their concern. As Pablo says, antifreeze has corrosion inhibitors and it is a non problem.
jldcol - pH 7 does mean 10-7 protons, but it also means 10-7 hydroxyl ions. H+OH=H2O. When the water goes through the cation units it produces acidic water, but this is neutralized going through the anion units, where sulfates, nitrates, and other anion units are replaced with the hydroxyl ions, so that you have the H+ and OH- combined....
Probably more info than anyone wants to know.
Years ago Mercedes Benz used to recommend not using di water for cooling systems over concern for the affinity of di water to pick up oxygen, though I never understood their concern. As Pablo says, antifreeze has corrosion inhibitors and it is a non problem.
jldcol - pH 7 does mean 10-7 protons, but it also means 10-7 hydroxyl ions. H+OH=H2O. When the water goes through the cation units it produces acidic water, but this is neutralized going through the anion units, where sulfates, nitrates, and other anion units are replaced with the hydroxyl ions, so that you have the H+ and OH- combined....
Probably more info than anyone wants to know.
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Boomer - your definition of deionized water is too limited. RO does not remove all of the ions, though it can remove a high percentage of them,and for high purity needs is usually pre-treated with a softener to prevent scaling of the membranes and then passed through a mixed bed deionizer. They usually require high pressure pumps and can be maintenance intensive. Older plants often put an RO unit in front of their deionizer and then do not have to regenerate their old units nearly as often, and then often reduce the flow rate but that is compensated for by running a much higher percentage of the time. I have been retired for some time so I am sure many of the issues of RO have been improved.
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Wikipedia has a pretty good description of ion exchange, and includes a photo of what they look like, small amber colored spheres.
ion exchange
ion exchange
Uncertain of the description of water generating ions. The pH scale is based on the dissociation of water, and is 10-14, and thus how you get neutral being pH of 7. See this: dissociation of water
JohnK gave a good explaination. It is true that water itself maintains the 10^14 H3O+ and OH- sum. Water can contain large numbers of Ca++, Na+, Cl-, SO4--, CO3--, etc. ions. They can be removed by reverse osmosis or ion exchange. Such water is called deionized even though it still has its H3O+ and OH- ions. Bare protons are rare in water.
We use a heap of de-ionised water in the power stations.
Produced using the process John K described. Clarifier, sand filter, degassifier (I think before the cation), cation exchange, anion exchange, a mixed bed, then through to the plant.
The condensed steam is then passed over another mixed bed (polisher) before going to the boiler. (3uS/m conductivity ?).
This is in a system, where brass is mechanically connected to mild steel, alloy steel, and stainless steel.
Corrosion in the pure water is next to nil.
Ammonia added in tiny quantities before the high pressure stuff brings the pH to 9 and scavenges oxygen.
Produced using the process John K described. Clarifier, sand filter, degassifier (I think before the cation), cation exchange, anion exchange, a mixed bed, then through to the plant.
The condensed steam is then passed over another mixed bed (polisher) before going to the boiler. (3uS/m conductivity ?).
This is in a system, where brass is mechanically connected to mild steel, alloy steel, and stainless steel.
Corrosion in the pure water is next to nil.
Ammonia added in tiny quantities before the high pressure stuff brings the pH to 9 and scavenges oxygen.
I would expect 3 uS/cm conductivity or less if not exposed to air.
Our mixed beds typically put out 0.055 uS/cm. I expect Shannow's comment applies after the addition of the ammonia. In power plants all of these measurements are made in line, or in a side stream where it is not exposed to air.
I personally think RO water is more than fine.
I agree Al & that is what I use at home.
I agree that RO is likely to be fine, but the question in the beginning was is DI water good enough. In some locations tap water is good enough, but in many it is not, as it varies greatly.
DI is fine.
Thanks for all of the answers and Chem lessons
Brian
Brian
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