Sciencemadness Discussion Board

Beware "Deionised" water

YT2095 - 25-10-2007 at 04:34

the stuff you buy at car shops for topping up car batts.
Some of it contains Chlorine!:mad:

I nearly lost 3 days work purifying silver metal for silver Nitrate as a result of this.

I am NOT happy!:mad:

Antwain - 25-10-2007 at 05:46

You should send ugly words to the manufacturer. As far as I know, chloride is a battery killer too :o

UnintentionalChaos - 25-10-2007 at 10:14

Even white distilled vinegar has a fair amount of chloride in it (learned that when making lead acetate). I just buy distilled water by the gallon..around 70 cents US each and no chloride contamination.

JohnWW - 25-10-2007 at 17:00

Would rain-water do for the purpose? I find that it seems to be OK for topping up lead-acid batteries, although it is known to contain dissolved CO2.

chemkid - 25-10-2007 at 17:19

Rain water is often acid (acid deposition), however this would be OK for lead-acid batteries, it would not work for most experiments. Furthermore, there is usually a good bit of suspended solids in rain water as well.

Chemkid

bio2 - 25-10-2007 at 17:36

I once tested some distilled water intended for batteries
and it was 80PPM TDS. Only one state in USA (California)
has standards for distilled water and it is <10PPM which is
still not very good for some purposes.

For my use in making ionic/collodial silver I had to buy RA
grade double distilled water which sometimes still tested at
almost 1PPM.

Buyer beware when purchasing distilled water because the TDS is determined by how often the maker cleans their stills. In my experience some brands are more reliable than others.

Good quality de-ionized water is lower in TDS than distilled.
Now I run regular grade RO water through de-ionizing resin and get better results than with the RA double distilled water.

[Edited on by bio2]

chemrox - 25-10-2007 at 19:16

I've been very fortunate in having spent most of my life in two places that both had(ve) extraordinary water quality; one of them had water with an average TDS around 6 mg/L (PPM is an air parameter- vol/vol). The other is about the same, ranging from 4-10 mg/L. I'm not surprised to find the DI water of commerce is sometimes a rip. The "purified water" or "spring water" is usually tap from someplace that one of the big soft drink companies has a contract with. It's a worldwide scandal; the appropriation of water by Cocal Cola and Pepsi for the purpose of selling bottled water. Municipal water supplies all over Latin America have been sold to these pirates and then sold to you as "Mountain Spring Water." There are regs being promulgated as we 'speak.' However, technically the water can be 'deionized' and still contain chlorine. I don't think there's any kind of standard for DI. Amazingly, my office mate and landlord bought a cheap, mount it on the faucet, water purifier that completely rids the water of chlorine. Even after years of service. The health food store has a machine that runs reverse osmosis on city water and the city water here is never over 10 mg/L TDS and rarely is that high. So chlorine and flouride are the two concerns. So, this was really long winded to get to my recommendation: buy water from a vendor that uses RO or get a purifier and check it with a swimming pool kit from time to time. Or, as has been said, get the distilled water, its usually OK. Can't have hypochlorite clogging up steam irons or the consumers *will* bitch.

[Edited on 25-10-2007 by chemrox]

evil_lurker - 25-10-2007 at 20:44

I have a 5 stage Barracuda RO unit with DI from http://aquariumwaterfilters.com/

Thing works great, it uses quality components, and its relatively cheap to @$230USD.

Includes inline TDS meter, pressure gauge, and storage tank.

Antwain - 26-10-2007 at 08:57

I could always pinch the "milli-Q" water from uni, but that stuff is not cheap and I reckon they wouldn't be happy if several liters disappeared. I usually use "deionised water" from the supermarket. It is only ~$1/L and isnt too bad for most things, but I don't know its actual assay.

Aqua_Fortis_100% - 26-10-2007 at 09:09

I get my 'distilled' water on the upper part of the fridge, as a crust of ice (upper part of the freezer because that is the only part which generally not touch the contents of the frezeer (foods, meat , etc)..and then I let it melt and store it. Is good at least for me..And maybe to most amateur that have an old non auto-de freezing refrigerator. The only drawback is that you have to wait a lot to get some amount.

the good thing is that is just free and easy to get :D

[Edited on 26-10-2007 by Aqua_Fortis_100%]

prole - 26-10-2007 at 09:22

The distilled water you buy in the store isn't pure or clean.

https://sciencemadness.org/talk/viewthread.php?tid=5506&...

YT2095 - 26-10-2007 at 09:31

well I wasn`t after ULTRA PURE, but something with less chlorine than Tap water would have been Nice!

I don`t give a crap about Phthalates and the likes, but the Cl2 is DAMNED annoying! :mad:

Klute - 27-10-2007 at 05:55

Off topic, I know, but ppm can also be used for concentrations: this is the unit we use for atomic and molecular emission spectrometry, and other analysis technics using highly diluted solutions.
It's even used in NMR (Hertz). So I guess the "parts per million" can be applied to anything that can be considered as a "part". Even humans for statistics, no? (that's e bit unlikely, I admit :) )

Sorry for the intrusion :)

12AX7 - 27-10-2007 at 11:41

1 ml == 1g H2O at 4C or so. Therefore, 1mg/L H2O = 1mg/1kg = 1m/1k = ppm.

In NMR, ppm refers to a shift in the resonant frequency of a precessing proton in a magnetic field. At some magnetic field strength, you might have 50.000 000 MHz on your TMS signal, and 50.000 050 MHz on a methyl's hydrogens, for a shift of 1 ppm. Molecular interaction happens to be expressed as a rather small ratio of the precession frequency, so ppm is constant whatever magnetic field you're testing at.

Tim

Klute - 27-10-2007 at 15:39

Yes, this is what enables spectras from different devices to be compared, as the NMR machines often have different ranges. I've always found it strange that proton couplings are still expressed in hertz, however. In that case I suppose the exact coupling value changes from device to device for a same proton.

Totally drifting out of topic though. I will refrend.

Traveller - 30-9-2012 at 09:15

I live in an area with high humidity. I have a small de-humidifier I keep going most of the time to keep the humidity in my house down to a tolerable level. It easily produces two litres of water daily that must be dumped.
Is this water equivalent to distilled water?

bahamuth - 30-9-2012 at 10:06

To get some good clean analytical water one might ask the local university or a local lab or the similar if one could buy or get some liters for free. RO water from a Millipore setup, which all labs have, is dirt cheap and good enough for most purposes.

18 Mohm water (MilliQ) water is also relative cheap by the liter, it is just the setup/instrument that costs a leg and an arm. I'd guess like $1 per L.

Lucky me, I get all my water from the lab, just fill RO water on 2.5 L carboys and put it in my backpack once a week or so:P

MilliQ water is a little more restricted but only because it takes several hours to fill up the tank which is 3 L or so..

Or even better, just make your own still, triple distill it and it is as good as most. And if you plan on storing it, filter it through a 0.2 micrometer filter to get rid of all the bacteria as to avoid growth.


As a side note, Ion Exchanged water is often called DI, or RO water, which in many cases means that just the alkaline earth ions are exhanged with sodium and potassium, also leaving the anions in there.

hissingnoise - 30-9-2012 at 10:19

Not really, it will contain dust specks, CO<sub>2</sub> and anything else in the air that's soluble!

triplepoint - 30-9-2012 at 10:24

Quote: Originally posted by Traveller  
I live in an area with high humidity. I have a small de-humidifier I keep going most of the time to keep the humidity in my house down to a tolerable level. It easily produces two litres of water daily that must be dumped.
Is this water equivalent to distilled water?


Dehumidifiers often develop a significant moldand bacteria buildup. Depending upon your intended use, that could present a problem.

unionised - 30-9-2012 at 12:00

Depending on what the local tap water is like, the water from a dehumidifier might be a good material to feed to a still.