Distilled water compared to RODI water

[aydemir]

I don't have an RODI machine but I have a water distiller which I use to fill up my nano. I was just wondering what the difference is with the two

[JohnniG]

Im not sure, ill stick around for this !

[Twistofer]

IMHO, not a whole lot of difference.

In distillation, water evaporates at 212 degrees F, leaving anything else, like salts and minerals, behind. When the vapor consenses, the "pure" water is then collected in your barrel or tub. However, there are some organic compounds, such as alcohol, which actually combine with water and evaporate together with water at a lower temperature. This is the main principle when making moonshine and other "distilled spirits." Water/Alcohol distills at about 173 degrees F and the collected vapor can reach about 95% (180 proof).

In RODI,essentially, four things happen. First, non-dissolved solids are filtered out (includes bacteria, sediment, etc). These are dependent on the physical size of the filter material (usually between 0.5 and 5 microns). Second, carbon removes certain organic and inorganic molecules by physically attaching to the molecule. Third, water is forced through the membrane, leaving other larger molecules behind and "washed" away with the "rejected" water (hence a "rejection" rating on the membrane). And finally, DI, the deionization process, is where a specific plastic compound removes whatever is left over, electircally charged particles from the remaining solution. Ideally, this leaves only H20, "pure" water which is collected in your tub or barrel.

Technically, RODI water should be purer.

[YoungREEFA]

When ever i would use distilled water it always came in at 0 tds. Besides walmart distilled water, that came in between 3-15

[dkeller_nc]

Originally Posted by aydemir

I don't have an RODI machine but I have a water distiller which I use to fill up my nano. I was just wondering what the difference is with the two

That would depend on what the materials of construction are of your distillation unit. As twistofer points out, in theory vaporized then condensed water will be very pure indeed, presuming the starting material doesn't contain low-boiling organic compounds.

In practice, however, one needs to use a unit that double or triple distills the water and is made of glass to achieve the purity level of a typical RODI system. That's because in a distillation unit that is affordable for the home, there's typically some amount of the boiling liquid that gets carried over to the product, carrying some degree of contaminants with it. And in many designs, the condenser is made of metal, which will add some degree of ions back to the water. It's unlikely, however, that that amount of ions will matter unless the condensing coil is copper.

[HumbleFish]

Should be fine unless you are using copper pipe distilled water (which I think is a thing of the past).

[aydemir]

So, theoretically, if my water distiller machine were 'perfect', it would produce pure H20 like the RODI unit?

[GothBoy]

Yes, but only if the input water was free of any compound with a boiling point near to, or below that of, water.

[aydemir]

ahh ok that makes sense