Does de-ionized water naturally re-ionize?

[ouroborus]

I don't know where I got the idea, but doesn't de-ionized water naturally re-ionize? How do you keep it de-ionized? Is this a rapid process? (What kind of time line are we talking about?) If so, what's the point?

 

[greens]

No. The polar compounds have actually been removed.
Plenty of ions still left in it, there is of course H and OH still.
Any non polar molecules are still there. It shouldn't be thought of as clean, or really, anything other than soft water.

But no, the water will stay soft unless you somehow re-added the nitrates, iron, calcium, and copper that was removed during the ion exchange.

 

[mcnumpty23]

as already said no

assuming its in a sealed glass or plastic bottle

where would it acquire the mineral ions to re-ionise

 

[TJ Hooker]

Not strictly related to your question, but deionized/distilled water exposed to air will naturally cause carbonic acid to form, resulting in weakly acidic water.

Just a little semi-related factoid.

 

[ouroborus]

No. The polar compounds have actually been removed.
Plenty of ions still left in it, there is of course H and OH still.
Any non polar molecules are still there. It shouldn't be thought of as clean, or really, anything other than soft water.

But no, the water will stay soft unless you somehow re-added the nitrates, iron, calcium, and copper that was removed during the ion exchange.

That lead me to these links which helped me understand this.

• 
  ■ Self-ionization of Water
  ■ Purified Water: Deionization

 

[gondo]

DI water will leach minerals from metal to re-ionize as you said. You can look up the use of DI water in Semiconductor manufacturing and other specialty electronic areas. In a sealed container it cannot reionize.

DI water is also very common for aquariums to keep fish happy. People take Reverse Osmosis water, run it through a deionizing filter, to get ultra pure water. Then they manually add minerals and stuff to get the desired water makeup for their species of fish.